Dimmable rearview assembly having a glare sensor

The present invention generally relates to an optical radiation sensor device, and more particularly to a sensor device incorporating an optical sensor.

Optical sensors are used in many different applications. In such photosensor applications, some properties of the sensing mechanism need to be within acceptable limits, and in certain photosensing applications, some need to be further characterized. Other characteristics of the sensor may extend the range of applications in which the sensor is suitable and / or provide easier or more economical design applications. The first characteristic, which has significantly different general requirements for each application, is the angular response characteristic of the sensor required for a particular application, that is, the angular response profile. The second characteristic is the optical gain, which is preferably large enough for the system to stably measure the lowest light level that needs to be detected in low light level measurements. A third characteristic is that the device needs to be equipped with a space-efficient aperture that is relatively small and aesthetically pleasing as an inlet for the light to be measured. A fourth property is the ability to separate the aperture from the electronic sensing device at a sufficiently and preferred variable distance. The fifth characteristic utilizes a separate component to sense light and characterize the angular response characteristic, resulting in the use of the sensor in a wide range of applications, further expanding the standardization of light sensing components. To be connected to.

The types of sensor devices used to detect light are composed of various packages. For example, the photoconducting sensor is often mounted on a circuit board and may or may not include a separate lens located in front of the sensor. In some photodiodes, a sensor die is mounted on a lead frame and sealed with a permeable epoxy resin. A portion of the epoxy encapsulating material is molded into the lens so that the incident light is focused on the sensor die. Such lenses have been made into a spherical surface or other surface of revolution that is symmetrical about an axis that is approximately perpendicular to the surface of the active sensing element. Unlike sensor configurations, where separate lenses are placed at intervals from the sensor, the lenses in these types of sensor devices are an integral part of the sensor, eliminating the space that separates the sensor from the lens. .. The main design difference that results from filling the space between the lens and the sensor with plastic is that the rate of light propagation decreases in inverse proportion to the index of refraction of the lens material. This effectively increases the focal length of the lens in proportion to the index of refraction of the material.

Figures 4A and 4B show two common sensor configurations, each with similar angular response characteristics, but with very different optical gains. In the first sensor configuration of FIG. 4A, the sensor is near the aperture and preferably has high optical gain. Placing the sensor near the aperture often adds cost due to the addition of parts and assembly processes, and often impairs the electrical design due to the lengthened electrical connection path to the sensor. In the second sensor configuration of Figure 4b, the sensors are located far away from the aperture and the optical gain is undesirably low. Although the placement of the sensor is convenient and low cost, satisfactory performance may be compromised or hindered because the reduction in optical gain can be severe for the overall design.

The angle between the straight lines 41a and 42a and the angle between the straight lines 41b and 42b are the same in each of the illustrated examples, the nominal angle between the 50 percent response points in the optical angle response profile for each of the sensors. Is shown. The light blocking portions of the housings 44a and 45a are shown in FIG. 4A with a partial view of the opposite sides of the aperture including the lens 43a. If the sensing element 48a is located closer to the case than the point 49a, which is the intersection of the straight lines 41a and 42a indicating the optical aperture, the lens, in some cases in combination with diffusion and / or defocus, the straight line 46a. May help reduce the field aperture from the angle between and 47a to the angle between the design target straight lines 41a and 42a. The lens 43a helps to collect the light incident on the sensor, which increases the optical gain of the sensor. In this way, the desired reduction in the entire field of view is achieved while increasing the optical gain of the system. A general requirement for this to work with thin single lenses in non-optical pipe mode is that the sensor 48a be placed closer to the aperture than the vertices 49a of the conical surface drawn by the straight lines 46a and 47a in Figure 4A. Is. The conical surface can be non-circular, but is used only as a temporary gauge for illustrative or design purposes. If the lens and / or filter is removed, the conical surface is aligned in the required viewing direction and inserted as much as possible into the provided aperture opening. (A region that is generally closer to the aperture than the points 49a or 49b can be referred to as the near-field region of each aperture.)

The light blocking portions of the housings 44b and 45b are shown in the partial view of FIG. 4B on the opposite sides of the aperture, including the diffuser lens and / or the surface 43b. In this case, the sensor 48b is farther from the aperture than the vertex 49b. The characteristics of point 49b are similar to those of 49a. According to another method, this is the point on the sensor side of the aperture that is farthest from the aperture, from which the aperture covers the entire field of view in which the sensor should respond to incident light or a substantial portion thereof. It is explained as a point that can be seen before placing the optical element inside. In this case, the sensor 48b is farther from the aperture than the point 49b, so the angle between the straight lines 46b and 47b is smaller than the angle between the straight lines 41b and 42b. In a three-dimensional representation, the solid angle defined by the aperture at point 48b where the sensor is located is at point 49b where the desired field of view can be seen in response to incident light through the aperture with the lens and / or filter removed. It is smaller than the solid angle defined by the aperture. In this case, an optical element 43b with a diffusing effect can be incorporated into the aperture and diffused enough to allow sufficient light coming in from typical directions 41b and 42b to hit the sensor 48b. If the effect is significant, diffuse from the field of view indicated by the angle between 46b and 47b to the field of view indicated by the angle between 41b and 42b, as required to meet the design objectives. An equilibrium point can be found where the effect expands the effective field of view. The disadvantage is that instead of concentrating the light and adding optical gain as achieved in the first embodiment, it enters through the aperture unobstructed and collides with the sensor before placing the diffuser. The diffuse effect of the diffuser spreads the light rays, which reduces the proportion of light rays that reach the sensor, effectively attenuating the light level. Therefore, a need for a sensor device configuration that can be located at a distance through the housing from the aperture in the housing without sacrificing optical gain.

One use of optical sensors is glare sensors for vehicle rear view assemblies. The rear view assembly can include electrochromic mirror elements and / or display elements. The electrochromic mirror element monitors the light level sensed by the rear facing glare sensor and uses that level to control the reflectance of the electrochromic mirror element, driving excessive glare from the headlights of other vehicles. It can be prevented from being reflected in the eyes of a person. Similarly, the intensity of the display can be changed according to the light level sensed by the glare sensor.

U.S. Pat. No. 6,831,268 discloses a sensor device that can be placed at a distance through the housing from the aperture within the housing of the rear view assembly without sacrificing optical gain. As disclosed in the patent, it can be advantageous to provide a diffuser across the aperture in the housing. In one particular embodiment, the sensor device is utilized as a glare sensor that senses light passing through an aperture formed on the bezel of the rear view mirror assembly, in which case a diffuser can be provided on the aperture.

<patcit num="1"><text>U.S. Pat. No. 6,831,268</text></patcit><patcit num="2"><text>U.S. Pat. No. 6,679,608</text></patcit><patcit num="3"><text>U.S. Pat. No. 6,379,013</text></patcit><patcit num="4"><text>U.S. Pat. No. 6,359,274</text></patcit><patcit num="5"><text>U.S. Pat. No. 5,471,515</text></patcit><patcit num="6"><text>U.S. Pat. No. 6,587,573</text></patcit><patcit num="7"><text>U.S. Pat. No. 6,670,207</text></patcit><patcit num="8"><text>U.S. Pat. No. 6,356,376</text></patcit><patcit num="9"><text>U.S. Pat. No. 6,521,916</text></patcit><patcit num="10"><text>U.S. Pat. No. 4,799,768</text></patcit><patcit num="11"><text>U.S. Pat. No. 5,036,437</text></patcit><patcit num="12"><text>U.S. Pat. No. 4,902,108</text></patcit><patcit num="13"><text>U.S. Pat. No. 5,204,778</text></patcit>

<p> Although the configuration disclosed in the '540 patent application works quite well, some automakers prefer to position the sensor device behind a mirror element or display element to minimize the external size of the bezel. There is. In addition, some automakers may offer a "theater seat arrangement" in which the rear seats are raised relative to the front seats on some of the vehicles. This results in a reduction in the proportion of light from the rear window that can be perceived within the field of view of the glare sensor. As long as the glare sensor perceives an average light level over its field of view, the theater seat seat arrangement reduces the average light level in other cases sensed by the glare sensor. In addition, in vehicles of the same model, the seat may have a light or dark upholstery, which can affect the light level sensed by the glare sensor when the seat is in the field of view of the sensor. Therefore, there is a need for a rear view configuration in which the glare sensor can be positioned behind the mirror or display element and the performance of the glare sensor is improved to take into account such positioning and to take into account changes in the field of view from the rear window.</p>

<p> Accordingly, one aspect of the invention is a housing adapted to be mounted on the vehicle and a reflective surface that is placed on the housing to provide the driver with an image of the rear view of the vehicle and through which a transparent window is formed. The rear view element includes the glare sensor device and a secondary optical element arranged between the glare sensor device and the rear view element, and is mounted behind the window of the rear view element so as to sense light passing through the window of the rear view element. It is to provide a vehicle rear view assembly with a glare sensor subassembly.</p><p> According to another embodiment of the invention, a housing adapted to be mounted on the vehicle, a rear view element located on the housing to provide the driver with an image of rear view from the vehicle, and mounted within the housing. A rear view assembly for a vehicle is provided, which comprises a circuit board and a glare sensor device surface-mounted on one surface of the circuit board to sense light from the rear of the vehicle.</p><p> According to another embodiment of the invention, a housing adapted to be mounted on the vehicle, a rear view element located in the housing to provide the driver with an image of the rear view of the vehicle, and behind the vehicle. A vehicle rear view assembly is provided that includes a glare sensor device that senses the light level of the vehicle and a glare subassembly that includes a secondary optical element configured to function as an anamorphic lens.</p><p> According to another embodiment of the invention, a housing adapted to be mounted on the vehicle and a rear view element and a rear view element arranged in the housing to provide the driver with an image of the rear view from the vehicle. A vehicle rear view assembly is provided with a glare sensor device mounted behind the rear view element to sense the passing light. The glare sensor device is an encapsulating material that encloses a support structure, a sensing circuit mounted on a support substrate to detect light and generate an electric output signal in response to the light, and a sensing circuit on the support structure. The encapsulant includes a lens portion for focusing incident light on the active surface of the sensing circuit and a lens for collecting and reorienting light not incident on the lens portion on the active surface of the sensing circuit. It is configured to define an optical collector portion that surrounds the portion.</p><p> According to another embodiment of the invention, a housing adapted to be mounted on the vehicle and a rear view element and a rear view element arranged in the housing to provide the driver with an image of the rear view from the vehicle. A vehicle rear view assembly is provided with a glare sensor device mounted behind the rear view element to sense the passing light. The glare sensor device is on a support structure that includes a support structure, a sensing circuit mounted on the support substrate to detect light radiation and generate an electrical output signal in response, and an integrated anamorphic lens. Includes an encapsulant that encloses the sensing circuit of.</p><p> These and other features, advantages, and objectives of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and accompanying drawings.</p>

Here, preferred embodiments of the present invention are referred to in detail, an example of which is shown in the accompanying drawings. Whenever possible, use the same reference code for the same or equivalent elements throughout the drawing.

FIG. 1 shows a sensor device 50 configured according to one embodiment of the present invention. FIG. 2 shows a sensor subassembly 10 incorporating the sensor device 50. The sensor device 50 comprises a support structure such as a printed circuit board or lead frame 60 and an integrated sensing circuit 15 having an active sensing region 57 mounted on the supporting substrate to sense light radiation, which is preferably visible light. Includes an encapsulant 62 that encapsulates the sensing circuit on the support structure. Generally, the encapsulant 62 forms a lens structure 20 including an integrated refracting lens portion 61 that preferably has an elliptical refracting surface for focusing incident optical radiation on the active surface 57 of the sensing circuit 15. The lens structure 20 further includes a light radiation collecting unit 53 that surrounds the lens unit 61, collects light radiation that does not enter the lens unit 61, and reorients it on the active surface 57 of the sensing circuit 15. The light radiation collecting unit 53 includes a parabolic reflecting surface 54 that reorients the incident light radiation toward the sensing circuit 15 by total reflection. Further, the light radiation collecting unit includes an annular light radiation light receiving surface 51, and the light receiving surface is on a plane perpendicular to the main axis of the elliptical lens unit 61 and is arranged around the elliptical lens unit 61. .. The encapsulant is preferably made of a permeable polymer.

The sensor subassembly 10 further includes a diffuser / aperture subassembly 30 including an aperture formed in the housing housing 31 and a diffuser arranged in the aperture formed in the housing 31. As shown in FIGS. 26 and 27, the housing housing 31 can be the housing housing of the rear view assembly. As used herein, the term "rear view assembly" refers to a rear view mirror assembly that has mirror elements such as electrochromic mirror elements, and a display for displaying images captured toward the rear of the vehicle by a rear-facing camera. It can be a rear view display assembly with elements, or a rear view mirror / display integrated assembly with both a mirror element and a display element that displays a rear image. Further details regarding the preferred configuration of the rear view assembly will be given after a more detailed description of the preferred sensor device below.

Having schematically described the structure of the sensor assembly of the present invention, the optical properties, functions, and advantages of such structures will be described below.

In the sensor configuration shown in FIG. 4C, it is desirable that the sensors configured as described above be placed at a considerable distance from the aperture to have high optical gain. The features that result in this desirable combination are part of the invention described herein.

In the explanatory diagram of FIG. 4C, the positioning and definition of 49c are the same as those of 49a and 49b (FIGS. 4A and 4B), and the positioning of the small area sensing circuit 15 is the same as that of 48b. A lens structure has been added that preferably encloses and preferably surrounds the sensor circuit 15, except that the lens and / or diffusing element 32 is designed to generally provide the desired profile of angular sensitivity for the entire system. , Other corresponding features are similar. The resulting system provides sufficiently high optical gain that exceeds Figure 4B.

The lens structure 20 functions to project a ray through the aperture into the active region 57 of the sensor circuit 15 and fills a significant portion of the relatively large cone angle, the extremum being a straight line in the exemplary embodiment. It is indicated by 46c and 47c. The lens does not need to maintain image integrity, but in some other respects it is comparable to a low F-number photographic lens. In addition, it is preferable to have an F number even lower than that practical in a normal imaging optical system. In a preferred structure, most of the light beam, represented by 45c, is focused on the sensor by the lens structure 20, emanating from the desired field of view and entering the system through the aperture. Light rays such as 44c that do not enter through the aperture preferably form a very small portion of the light that the lens orients in the active region of the sensing circuit 15. In the above, especially when the angle between 41c and 42c is large, only sampling of these rays is usually oriented to the active sensing region, but most of the rays directed to the active sensing region are at the light level. Preferably come from the direction in which is to be measured. The lens and / or diffusing unit 32 is designed to have a diffusing effect, which is a typical proportion of light rays emitted from within the regions ranged in the directions 41c and 42c in the exemplary embodiments. The lens structure 20 is adjusted to focus on the active region of the sensor circuit 15. Both the distribution and range of the scatter profile of the diffuser preferably have an angle-dependent magnitude and general extremum of the response profile of the optical system to meet the design objectives. The degree of scattering is also preferably reasonably close to the minimum amount required to meet the response profile goals, as the overall optical gain decreases as the scattering increases.

In some embodiments of the invention, the optical subassembly 30 may include a single negative lens element or even a positive lens element. However, it is preferable to have a fine pattern. For example, the pattern is repetitive or random in the diffusion effect, with a diffuser dispersed in the material covering the aperture, with a random or irregular rough surface, or by replicating a fine pattern. The ultrafine structure that can be produced allows it to be manufactured in fine arrays of small lens elements. Fine patterns can be generated by laser interference patterns, and such diffusers also utilize interference patterns generated by the fine features of the optical surface in addition to or in place of the reflection or refraction effect. Therefore, the desired light dispersion effect can be achieved.

As shown in FIG. 2, the light enters through the aperture and diffuser subassembly 30, travels some distance, and then some of the incident rays hit the lens structure 20 of the sensor device 50, where it hits the sensor. A part of the hit light beam is oriented to the light sensing region on the sensing circuit 15. Leads 59a-59d are electrically attached to a sensing circuit 15 and a related electrical control circuit 66 (FIG. 5) that functions to read or respond to the level of light hitting the sensor. The diffuser / aperture subassembly 30 functions to form a profile of the directional or spatial response of the sensor so that the directional sensitivity profile is satisfactory for the application. In some embodiments of the invention, the lens structure 20 of the sensor device 50 orients a sufficiently large portion of the light beam exiting the diffusing element and hitting the sensor on the light sensing region of the chip, which is usually sensed by the sensor. It is designed to provide overall system gain that is equal to or even greater than the optical gain achieved when located near the aperture, i.e. in the near vision region. When the sensor is located in the near-field region, it occupies a relatively large solid angle when the light from the field collides with the active region of the sensor, thereby orienting this light so as to contribute to the overall optical gain. Is often easily possible. The design of FIG. 2 preferably provides a design that maintains moderate, comparable, or better optical efficiency over the entire range of sensing circuit positioning options, which range may in some cases have a short field of view. It can be included, but in other cases it can be extended to distances far from apertures that are larger than the maximum range of near vision. One method of carrying out the present invention provides a lens system that directs light emitted from a diffuser element toward the light sensing element 15, and the effective solid angle of these light rays is similar to that of a similar system in the near field of view. Is almost satisfied. In this description, the active region 57 of the sensor is more sensitive to light rays entering the active surface from one direction or position than other light rays, and the sensor. The net effect on the output of a ray hitting the active region of is equal to the product of the efficiency of the ray entering the sensor surface at a particular angle and position and the intensity of this ray. This can be referred to as the response efficiency in response to light coming from a particular angle to the sensor to a particular point on the sensor. Also, the lens or combination of lens and diffuser can vary in efficiency in directing light rays to a particular angle of incidence and position, which is the specificity on the sensor that comes from a particular angle with respect to the sensor. It can be called the collection efficiency in response to the light to the point. Therefore, for a particular angle and incident point, the light receiving efficiency can be defined as the product of the response efficiency and the collection efficiency. It will be most accurate to integrate the light receiving efficiency over the solid angle at which light enters the active sensing region and, in some cases, use this integrated light receiving angle instead of the solid angle as a reference for comparing optical systems. In short, it is a desirable feature of the present invention that a large solid angle with respect to the sensing circuit 15 is substantially filled with light, and this solid angle generally includes a high-sensitivity region of the sensor with respect to incident light. Since the sensor has the highest response efficiency to vertical light and can have a near cosine response characteristic in which this response approaches zero for light rays that are substantially parallel or specular to the sensing surface, the incident light enters the sensor. It is generally preferable to give priority to the direction perpendicular to the sensing surface of a part of the total solid angle to be oriented. The angle between the straight lines 68 and 68a generally indicates the outer limit of the cone angle at which the rays are collected in the exemplary embodiments. As described below, the ribs that enclose the lead frame connection prevent it from occupying part of the cone ranged by the straight lines 68 and 68a. In combination with the scatter element, the efficiency of orienting the light beam at a particular angle of incidence and position can vary, which is the light coming from a particular angle to the sensor to a particular point on the sensor. It can be called a responsive collection efficiency. Therefore, for a particular angle and incident point, the light receiving efficiency can be defined as the product of the response efficiency and the collection efficiency. It will be most accurate to integrate the light receiving efficiency over the solid angle at which light enters the active sensing region and, in some cases, use this integrated light receiving angle instead of the solid angle as a reference for comparing optical systems. In short, it is a desirable feature of the present invention that a large solid angle with respect to the sensing circuit 15 is substantially filled with light, and this solid angle generally includes a high-sensitivity region of the sensor with respect to incident light. Since the sensor has the highest response efficiency to vertical light and can have a near cosine response characteristic in which this response approaches zero for light rays that are substantially parallel or specular to the sensing surface, the incident light enters the sensor. It is generally preferable to give priority to the direction perpendicular to the sensing surface of a part of the total solid angle to be oriented. The angle between the straight lines 68 and 68a generally indicates the outer limit of the cone angle at which the rays are collected in the exemplary embodiments. As described below, the ribs that enclose the lead frame connection prevent it from occupying part of the cone ranged by the straight lines 68 and 68a. In combination with the scatter element, the efficiency of orienting the light beam at a particular angle of incidence and position can vary, which is the light coming from a particular angle to the sensor to a particular point on the sensor. It can be called a responsive collection efficiency. Therefore, for a particular angle and incident point, the light receiving efficiency can be defined as the product of the response efficiency and the collection efficiency. It will be most accurate to integrate the light receiving efficiency over the solid angle at which light enters the active sensing region and, in some cases, use this integrated light receiving angle instead of the solid angle as a reference for comparing optical systems. In short, it is a desirable feature of the present invention that a large solid angle with respect to the sensing circuit 15 is substantially filled with light, and this solid angle generally includes a high-sensitivity region of the sensor with respect to incident light. Since the sensor has the highest response efficiency to vertical light and can have a near cosine response characteristic in which this response approaches zero for light rays that are substantially parallel or specular to the sensing surface, the incident light enters the sensor. It is generally preferable to give priority to the direction perpendicular to the sensing surface of a part of the total solid angle to be oriented. The angle between the straight lines 68 and 68a generally indicates the outer limit of the cone angle at which the rays are collected in the exemplary embodiments. As described below, the ribs that enclose the lead frame connection prevent it from occupying part of the cone ranged by the straight lines 68 and 68a. It is a desirable feature of the present invention to include a high-sensitivity region of the cell. Since the sensor has the highest response efficiency to vertical light and can have a near cosine response characteristic in which this response approaches zero for light rays that are substantially parallel or specular to the sensing surface, the incident light enters the sensor. It is generally preferable to give priority to the direction perpendicular to the sensing surface of a part of the total solid angle to be oriented. The angle between the straight lines 68 and 68a generally indicates the outer limit of the cone angle at which the rays are collected in the exemplary embodiments. As described below, the ribs that enclose the lead frame connection prevent it from occupying part of the cone ranged by the straight lines 68 and 68a. It is a desirable feature of the present invention to include a high-sensitivity region of the cell. Since the sensor has the highest response efficiency to vertical light and can have a near cosine response characteristic in which this response approaches zero for light rays that are substantially parallel or specular to the sensing surface, the incident light enters the sensor. It is generally preferable to give priority to the direction perpendicular to the sensing surface of a part of the total solid angle to be oriented. The angle between the straight lines 68 and 68a generally indicates the outer limit of the cone angle at which the rays are collected in the exemplary embodiments. As described below, the ribs that enclose the lead frame connection prevent it from occupying part of the cone ranged by the straight lines 68 and 68a.

In the illustrated diffuser and aperture assembly 30, preferably fragment portions 31a and 31b of the opaque housing housing 31 are shown. The surface 35 of the diffuser 32 includes substantially parallel grooves. These grooves have the function of increasing the dispersion of light in a direction substantially parallel to the paper surface. The bottom surface 37 of the diffuser assembly 30 is an irregular surface that functions to diffuse light approximately equally in all directions. The light beam 34 is refracted by the surfaces 35 and 37 and travels through the refracting lens 61 as a light beam 39, which the refracting lens 61 focuses on the active sensing surface 57 as a light ray 63. The ray 16 is also refracted by the lens 61 and focused on the active region 57. The ray 16 is closer to the outer limit 55 of the refracting lens 61 than the ray 39. The light rays 11, 12, and 13 enter the upper surface of the lens structure 20, are reflected by the reflection surface 54 by total reflection, and hit the active sensing region 57. The order of the reflected rays is reversed from the order of the incident rays. The lens 61 is set to a depth at which the outer reflected light beam 67 just deviates from the edge 55. In the lens structure 20, the refracting portion 61 occupies the central portion of the cone of the light beam oriented in the active sensing region 57. The parabolic reflector 54 occupies the outer portion of the cone. The combination of the reflective lens and the refracting lens complement each other so as to occupy almost the region between the straight lines 68 and 68a. The resulting dispersion is greater in the direction parallel to the paper surface due to the combined and additive effects of the unidirectional dispersion of the surface 35 and the multidirectional dispersion of the surface 37. The result is a sensor that has a substantially wider field of view in the direction parallel to the paper surface than in the direction perpendicular to the paper surface.

The integrated sensing circuit 15, part of which is the active sensing region 57, is attached to the lead frame 60. The active sensing region 57 can be as small as 100 microns in diameter, for example. The sensing area is shown as a ridge in the figure simply to make it stand out. The actual part is likely to be coplanar or very slightly recessed. The attachment of the sensor circuit 15 to the lead frame 60 can be achieved by one of the electrical connections using conductive epoxy and the other connection by lead bonding, or lead all of this connection. It can also be formed by bonding. The lead portions 59a to 59d extend from the package and are electrically connected to the printed circuit board, and this portion is attached to the printed circuit board. Preferably, the lead portions 59a to 59d are configured to be surface-mounted on the circuit board. Surface mounting electronic components such as sensor device 50 is preferable to through-hole mounting where leads are inserted through holes in the circuit board and then soldered onto the circuit board on the opposite side of the component. .. On the other hand, surface mounting is performed on only one side of the circuit board.

FIG. 1 is an isometric view of the sensor device 50. A typical ray 112 enters the top surface 51 and is reflected off the surface 54 by total internal reflection to the active sensing area 57 of the sensor circuit 15. Similarly, the light beam 112a is reflected by a similar surface on the back side of the device and also hits the active sensing area. The light beam 113 enters through the recessed refracting lens 61 and is focused on the active sensing region. The rib portion 104 accommodates the lead frame and serves to allow a gap for retracting the mold from this portion. Section 106 is one of two sections of ribs that have been enlarged to support the leads 59a and 59b. Leads 59c and 59d extend from symmetrically arranged expansion sections 106a. Dotted line 111 is included for explanatory purposes to define the extent of regions 110 and 110a. This region is above the ribs 104 and 104a that are joined to the parabolic reflector 54. Light rays entering this region are generally not oriented to the active sensing region. This portion is preferably formed by a two-part mold having a parting line commonly shown by the representative lines 107, 107a, and 107b.

FIG. 3 shows a part of the lead frame subassembly 60 to which the integrated sensor circuit 15 is joined. Only four of the devices are shown. The actual assembly contains as many as 64 devices that fit into one of the transfer molding sections. The lead frame assembly includes holes (represented by 73) used to place and hold the lead frame during the assembly process. Element 74 of the lead frame subassembly comprises two connecting pins 74a and 74b and a pad 74c to which the silicon sensor circuit 15 is mounted. The element 74 also functions as a cross-connecting link to hold the lead frame assembly together before separating this portion. The dotted rectangle represented by 71 represents the area punched out to separate the parts after the molding process is complete. Lead bonding wires 76 and 78 connect the bonding pads on the silicon sensor circuit 15 to connection pins 75 and 79, respectively. When the device is separated, pins 74a and 74b function as leads 59c and 59b, respectively, and pins 75 and 79 function as leads 59d and 59a, respectively. The circular element 20 represents the contour features of the plastic lens formed on this part. After joining the light sensing die to the lead frame to form a connection, the lead frame is placed in the transfer mold and the plastic lesbian assembly shown in FIGS. 1, 2 and 4C is transfer molded onto the lead frame. The lens is a component and has the advantage of serving to enclose the component. The lens can also be molded with a conventional two-part mold. After molding this part, it is separated and deburred to form the individual parts shown in FIG.

In a preferred configuration, the lens system is designed to focus light entering from a narrow beam angle approximately parallel to the axis of the lens system onto the active sensing area. In this system, the reflective section is a parabolic section where the focus is largely on the light sensing area of the receiver. The refracting lens is preferably elliptical and is designed to focus a light beam parallel to the axis of the system to the center of the light sensing area. The main axis coincides with the axis of the lens system, the focal point farthest from the tip of the lens coincides with the center of the light sensing area, and the ratio of outer diameter to inner diameter provides the optimum focus for the color light that optimizes the system. The elliptical lens selected so is a design choice that serves this purpose. The focal length of the parabolic section is the outside of a cone of light designed so that the light beam parallel to the axis of the lens that hits the active portion of the parabolic section at the point closest to the central axis of the lens is focused on the sensor by the optical system. It is selected to be reflected at an angle that occupies the limit. Even if the focal position of the ellipse, the adjustment of the spindle, and the ratio of the outer diameter to the inner diameter are selected as outlined above, the size of the entire ellipse can be freely adjusted. It is preferable to adjust the size of the ellipse so that the outer edge of the elliptical lens is just high enough for the light rays reflected from the outermost limit of the paraboloid to the sensing surface in the lens structure to pass through. As the diameter of the refracting lens increases, the inclination of the outer limit becomes too large. In other words, there is a practical maximum cone angle that can be occupied by a single-sided lens made of a material with a given index of refraction. This is a major factor influencing the choice of balance between the diameter of the refracting lens and the diameter of the parabolic reflector. The overall size of the lens assembly can be adjusted. This size need not be small enough to have an unnecessarily tight tolerance and must be large enough to fit the enclosed sensor assembly under the refracting lens. Also, the parabolic reflector needs to be large enough so that the area taken from the reflector by the ribs that enclose the connecting reeds is not an undesired large portion of the total reflection area. Illustrative dimensions are below It is a street. The semi-outer diameter of the elliptical lens 61 is 1.529 mm, the semi-inner diameter of the elliptical lens 61 is 1.163 mm, the focal length of the parabolic reflector 54 is 0.2887 mm, the radius of the refracting lens 61 is 1.0 mm, and the radius of the parabolic reflector 54. Is 2.2 mm at the upper end, and the refractive index of the plastic encapsulant 62 is 1.54.

The encapsulant 62 can be made of a single material, or the name "SENSOR DEVICE HAVING AN ANAMORPHIC LENS" filed by Jon H. Bechtel et al. On January 10, 2002. Can be made of more than one material as disclosed in US Pat. No. 6,679,608, assigned to the assignee of the invention.

The sensing circuit 15 can include any form of an optical sensor device such as a photodiode, cadmium sulfide CdS cell, and the like. The preferred sensing element was transferred to the transferee of the invention of the name "VEHICLE EQUIPMENT CONTROL WITH SEMICONDUCTOR LIGHT SENSOR" filed by Jon H. Bechtel et al. On January 25, 2000. The photodiode is disclosed in US Pat. No. 6,379,013, and US Pat. No. 6,359,274 under the name "PHOTODIODE LIGHT SENSOR" filed by Robert H. Nixon et al. On May 7, 1999. The structural parts of the processing circuit 66 that interfaces with the sensor device 50 and the sensing circuit 15 will be described below with reference to 5 to 22.

Here, with reference to FIG. 5, the processing circuit 66 and the sensing circuit 15 will be described in more detail. The processing circuit 66 and the sensor circuit 15 are interconnected by a single line 164 that transmits the interconnect signal 186, which signal advantageously comprises both the photosensor sensitivity control signal and the resulting photosensor output signal. Can be done. A microcontroller can be used to implement the processing circuit 66, which is the transistor element Q1 and buffer 192 connected to output pin 188, or other input / output (I / O) connected to signal line 164. ) Includes pin structure. Transistor element Q1 can be implemented using a suitable transistor such as a field effect transistor (FET) connected between signal pin 188 and ground. Transistor Q1 is controlled by a control line 190 connected to the base of transistor Q1. A buffer 192 is also connected to signal pin 188 to insulate the signal line 164 from the signal levels present in the microcontroller.

As described above, the sensor device 50 includes an encapsulant 62 that encapsulates the integrated sensing circuit 15. The encapsulant 62 includes a lens 61 for passing light 176 incident on the exposed light converter 178 through. The encapsulant also houses and holds the power supply pin 180, the ground pin 182, and the signal pin 184, which are preferably part of the lead frame 12. By using only the three pins 180, 182, and 184, the cost of the sensor device 50 and the associated processing circuit 66 is significantly reduced.

The sensing circuit 15 is connected to the processing circuit 66 via a bus 164, and the bus transmits an interconnection signal 186 between the signal pin 184 of the sensing circuit 15 and the signal pin 188 of the processing circuit 66. As described below, signal pins 184, 188 are tri-state ports through which the interconnect signal 186 can supply both an input to the sensing circuit 15 and an output from the sensing circuit 15.

In the sensing circuit 15, there is a transistor Q2 that can be mounted using a suitable transistor such as a FET element. Transistor Q2 is connected between signal pin 184 and ground. Transistor Q2 is controlled by output pulse 194 connected to the gate of Q2. The constant current source 196 is connected to signal pin 184, and if neither transistor Q1 nor transistor Q2 is ON (high logic level), the interconnect signal 186 is pulled to a high logic level. The constant current source 196 provides a nominal approximately 0.5 mA and pulls up the interconnect signal 186. Connect the input of the Schmitt trigger reverser 198 to signal pin 184. Inverters 200 and 202 connected in series follow the Schmitt trigger inverter 198. The output of the inverting device 202 clocks the D flip-flop 204. The output of the multiplexer 206 is connected to the D input of the flip-flop 204. The selective input of the multiplexer 206 is such that the D input of the flip-flop 204 is not asserted when the output pulse 194 is asserted, and the D input of the flip-flop 204 is asserted when the output pulse 194 is not asserted by the output pulse 194. Driven. The output of the NAND gate 208 connects to the low-asserted reset 210 of the flip-flop 204. The output of the flip-flop 204 is the integrated pulse 212. The outputs of the integrated pulse 212 and the reversing device 200 are inputs to the NAND gate 208. The optical-pulse circuit 214 receives the integrated pulse 212 and the output of the exposure transducer 178 to generate an output pulse 194.

The sensor circuit 15 can advantageously include a light-shielding transducer 216 that does not accept light 176. The shading transducer 216 has substantially the same configuration as the exposure transducer 178 and is of the same size and material as the converter 178. The optical-pulse circuit 214 utilizes the output of the light-shielding transducer 216 to reduce the effects of noise on the exposure transducer 178.

Here, with reference to FIG. 6, a timing diagram showing the operation of the circuit configuration of FIG. 5 is shown. First, the low-asserted interconnect signal 186 is high. If the state of the flip-flop 204 is 1, both inputs to the NAND gate 208 will be high, reset 210 will be asserted, and the state of the flip-flop 204 will be forced to zero, so that the flip-flop 204 The state should be zero.

At time 220, control logic 66 asserts control line 190 to turn on transistor Q1. The interconnect signal 186 is then pulled low at time 222. The output of the inverting device 202 transitions from low to high, setting the state of the flip-flop 204 to 1 (ie, high logic level), which asserts the integrated pulse 212 at time 224. The light-pulse circuit 214 starts integrating the light 176 incident on the exposure transducer 178. At time 226, control line 190 goes low and turns off transistor Q1. The difference between the time 226 and the time 220 is the integrated time 228 obtained by the control logic 66. Since both transistors Q1 and Q2 are off, the interconnect signal 186 is pulled high by the current source 196 at time 230. Since both the output of the inverting device 200 and the integrated pulse 212 are high, the reset 210 is asserted to change the state of the flip-flop 204 to zero, and the integrated pulse 212 is deasserted at time 232. It signals the light-pulse circuit 214 to stop integrating the light 176 incident on the exposure transducer 178.

At time 234, the light-pulse circuit 214 asserts the output pulse 194 to start outputting light intensity information. When the output pulse 194 is asserted, the transistor Q2 turns on and pulls the interconnect signal 186 low at time 236. As a result, the reversing device 202 outputs a low-high transition and clock-controls zero as the state of the flip-flop 204. The optical-pulse circuit 214 deasserts the output pulse 194 at time 238. The difference between time 238 and time 234 is the light intensity time period 240, which indicates the amount of light 176 incident on the exposure converter 178 over the integration period 228. Transistor Q2 turns off when the output pulse 194 becomes low at time 238. Since the transistors Q1 and Q2 are both off, the interconnect signal 186 is pulled high at time 242. The buffer 192 of the control logic 66 detects the transition of the interconnection signal 186 at times 236 and 242. The time difference between time 242 and 236 is used by control logic 66 to measure the intensity of light 176 received by sensing circuit 15.

When the light-shielding transducer 216 is included in the sensing circuit 15, the time difference between the deassertion of the integrated pulse 212 at time 232 and the asserting of the output pulse 194 at time 234 is partly due to the thermal noise in the sensing circuit 15. to cause. This difference is expressed as the thermal noise time period 244. The thermal noise time period 244 is utilized by the control logic 66 to measure the temperature of the sensing circuit 15 or more simply identify when the noise level of the sensing circuit 15 is too high for a reliable read. You may use it to do. If the temperature of the sensing circuit 15 exceeds a preset limit, the control logic 66 can disable the automatic control of the vehicle equipment.

FIG. 7 shows a timing diagram of the integrated duration control and sensor output of the optical sensor. The charge accumulation sensing circuit 15 exhibits increased sensitivity and increased dynamic range over a variable integration time period. The total amount of photoinduced charge that can be effectively measured is limited. Therefore, in the presence of bright light, a short integration time is desirable to avoid saturation. However, when using a short integration time in the micro-light state, the charge signal can be lost in the noise inherent in the sensing circuit 15 (ie, the signal-to-noise ratio is so low that the signal level becomes undetectable. ).

The control line 190 includes a series of integration time periods with variable lengths. In the illustrated embodiment, a short integrated pulse 240 with a short integrated time period 242 is generated. Semiconductor light sensors can output short pulses in a completely dark environment due to noise. Therefore, any sensor output pulse 194 whose duration is below the threshold, such as the short signal pulse 244, is ignored by the control logic 66. Next, a medium integration pulse 246 with a medium integration time 248 is generated. The resulting medium signal pulse 250 has a duration indicating the amount of light incident on the sensor circuit 15 during a medium integration time of 248. A long integrated pulse 252 with a long integrated time 254 is generated. If the sensing circuit 15 is bright enough, saturation will occur. Therefore, long signal pulses 256 with a duration above the threshold are also ignored by control logic 66. The signal represented by the control line 190 can be generated outside the sensing circuit 15 by the control logic 66 or the like, or can be generated by the sensor logic inside the sensor circuit 15. Sensitivity is adjusted by changing the integration time. By varying the sensitivity by giving consecutive cumulative time periods of different durations, it is possible to detect the appropriate sensitivity and select in response. A significant advantage of the sensor with the bidirectional interconnect signal 186 is that the control logic 66 controls the sensitivity of the sensor circuit 15 by varying the integration time of the sensor, dynamically compensating for different light conditions. It is a point that can be done.

Figure 8 shows the incident light 176 as C._SLIt is a schematic diagram which shows the light-pulse circuit 214 including the exposure converter which converts the charge stored in the light storage capacitor 304 shown by. The exposure converter 178 is a photogate sensor described in US Pat. No. 5,471,515 of the name "ACTIVE PIXEL SENSOR WITH INTRA-PIXEL CHARGE TRANSFER" given to E. Fossum et al. It can be any device that can convert light 176 into a charge, such as. The optical converter 178 may be a photodiode as described below. Unless otherwise stated, the following description does not depend on the particular type or configuration of exposure transducer 178.

The optical-pulse circuit 214 connected to the converter 178 receives the integrated pulse 212 and outputs an optical comparator signal proportional to the amount of light 178 colliding with the converter 178 during the integrated time pulse 212. The optical-pulse circuit 214 operates under the control of sensor logic 306. The sensor logic 306 is the exposure transducer output 312 and V_DDGenerates a reset signal 308 that controls the switch 310 connected to and from. The sensor logic 306 also generates a sample signal 314 that controls a switch 316 between the output 312 of the exposure transducer and the optical storage capacitor 304. The voltage across the optical storage capacitor 304, i.e. the optical storage capacitor voltage 318, is supplied to one input of the comparator 320. The other input of the comparator 320 is the lamp voltage 322 across the lamp capacitor 324. The lamp capacitor 324 has a current I_RIs parallel to the current source 326 that generates. Sensor logic 306 also has lamp voltages 322 and V_DDGenerates a ramp control signal 328 that controls the switch 330 connected to and from. The comparator 320 produces the output 194 of the comparator based on the relative level of the optical storage capacitor voltage 318 and the lamp voltage 322. The sensor logic 306 can generate the reset signal 308, the sample signal 314, and the lamp control signal 330 based on the internal generation timing or the external generation integrated pulse 212.

Here, referring to FIG. 9, a timing diagram showing the operation of the optical-pulse circuit 214 of FIG. 8 is shown. The measurement cycle begins at time 340 when the sample signal 314 is asserted while the reset signal 308 is asserted. This closes the switch 316 and the voltage level 342 of the optical storage capacitor voltage 318 indicates V._DDCharge the optical storage capacitor 304 up to. Then, at time 344, the reset signal 308 is deasserted, the switch 310 is opened, and the integration time period 346 is started. During the integration time period 346, the light 176 incident on the exposure transducer 178 generates a negative charge, causing a voltage drop 348 of the optical storage capacitor voltage 318. At time 350, the lamp control signal 328 is asserted, the switch 330 is closed, and the lamp voltage 322 is the V at voltage level 352._DDThe lamp capacitor 324 is charged so as to be.

The sample signal 314 is deasserted at time 354 to open switch 316, which ends the integration time period 346. At some time 356 after time 354 and before the next measurement cycle, the reset signal 308 must be asserted to close switch 310. At time 358, the lamp control signal 328 is deasserted to open switch 330. This causes the lamp capacitor 324 to discharge at a constant rate through the current source 326 as indicated by the voltage drop 360 of the lamp voltage 322. As the voltage level 362 indicates, the output 332 of the comparator is in the non-asserted state because the lamp voltage 194 is initially higher than the voltage 318 of the optical storage capacitor. At time 364, the voltage drop 360 of the lamp voltage 322 falls below the voltage 318 of the optical storage capacitor, and the output 194 of the comparator is asserted. At the output 194 of the comparator, the lamp control signal 328 is asserted, the switch 330 is closed, and the lamp voltage 322 is V._DDIt remains asserted until time 366 to pull to. The difference between time 366 and time 364, indicated by pulse duration 368, is inversely proportional to the amount of light 176 received by the exposure converter 178 during the integration time period 346. The integration time period 346 can be set directly by the integration pulse 212 or the signal generated from the integration pulse 212. It is assumed that the integration time period 346 is proportional to the width of the integration pulse 212, and the integration pulse 212 is proportional to the pulse width of the control line signal 190 of the circuit of FIG.

FIG. 10 is a schematic diagram of a modified light-pulse circuit 214a with noise correction. The modified light-pulse circuit 214a improves the light-pulse circuit 214 by incorporating a light-shielding transducer 216 and related electronics. The shading transducer 216 preferably has the same configuration as the exposure transducer 178. However, the shading transducer 216 does not accept light 176. Therefore, the charge generated by the shading transducer 216 is a function of noise only. This noise is effectively primarily due to heat. By providing the light-shielding transducer 216 having the same configuration as the exposure transducer 178, the exposure transducer and the shielding transducer can have the same surface area and material composition and can be deposited on the same die. The noise signal generated by the shading transducer 216 is very close to the noise in the signal generated by the exposure transducer 178. By subtracting the signal generated by the shading converter 216 from the signal generated by the exposure converter 178, the influence of noise in the optical converter 178 can be significantly reduced.

Reset signal 308 is a shielding transducer output 384 and V_DDControls the switch 382 connected to and from. Sample signal 314 is the output of the shielding transducer 384 and C_SNControls the switch 386 connected to the noise storage capacitor 388 shown in. The noise storage capacitor voltage 390, which is the voltage across the noise storage capacitor 388, is one input to the comparator 392. The second input to the comparator 392 is a ramp voltage 322. The output of the comparator 392, i.e. the noise comparator output 394 and the comparator output 194, serve as inputs to the exclusive OR gate 396. The exclusive OR gate 396 produces an exclusive OR output 194 indicating the intensity of light 176.

FIG. 11 is a timing diagram showing the operation of the optical-pulse circuit 214a of FIG. The optical-pulse circuit 214a functions similarly to the optical-pulse circuit 214 with respect to a reset signal 308, a sample signal 314, an optical storage capacitor voltage 318, a lamp voltage 322, a lamp control signal 328, and a comparator output 194. The sample signal 314 is asserted at time 340 while the reset signal 308 is being asserted. Both switches 382 and 386 are closed and the noise storage capacitor voltage 390 voltage level 410 indicates V_DDCharge the noise storage capacitor 388 up to. At time 344, the reset signal is deasserted to open the switch 382, and the charge generated by the noise in the shading transducer 216 causes a voltage drop 412 at the noise storage capacitor voltage 390. At time 354, the sample signal 314 is deasserted and the integration time period 346 for noise collection ends. At time 358, the lamp control signal 328 is deasserted, causing a drop in lamp voltage 322. As the voltage level 414 indicates, the output 394 of the noise comparator is in a non-asserted state because initially the voltage 322 of the lamp is greater than the voltage 390 of the noise storage capacitor. The output 194 from the comparator 396 is also in the non-asserted state, as the output 332 of the comparator is also in the non-asserted state, as the voltage level 416 indicates. At time 418, the lamp voltage 322 drops below the level of the noise storage capacitor voltage 390, asserting the output 394 of the noise comparator. Since the noise comparator output 394 and the comparator output 332 are different, the output 194 from the comparator 396 is asserted. At time 364, the lamp voltage 322 drops below the level of the optical storage capacitor voltage 318, asserting the output 194 of the comparator. Since the noise comparator output 394 and the comparator output 194 are both asserted here, the output 194 from the exclusive OR gate 396 is not asserted. The difference between time 364 and time 418, that is, the output pulse duration 420, is the time proportional to the intensity of the light 176 incident on the exposure converter 178, minus the noise generated by the shading converter 216 over the integrated time period 346. Have a period. The duration between time 418 and time 358, or noise duration 422, is directly proportional to the amount of noise generated by the shading converter 216 over the cumulative time period 346. Since most of this noise is thermal noise, the noise duration 422 indicates the temperature of the shielded optical converter 216. Lamp control signal 328 asserts at time 366

In circuits where very high light levels can be incident on the sensor, it may be preferable to include a comparator (not shown) that terminates the output pulse when the voltage 318 falls below a predetermined threshold. This has the effect of limiting the maximum duration 420 of the output pulse at signal 194.

Next, with reference to FIG. 12, a schematic view of the implementation of the sensor circuit 15 of FIG. 10 using a photodiode as an optical transducer is shown. The optical-pulse circuit 214b is mounted using an exposed photodiode 430 for the exposure transducer 178 and a shielded photodiode 432 for the light-shielding transducer 216. The anode of the exposed photodiode 430 is connected to ground and the cathode is V via transistor Q20._DDConnected to. The base of transistor Q20 is controlled by reset signal 308. Therefore, the transistor Q20 functions as a switch 310. Transistors Q21 and Q22 are V_DDIt is connected in series between and ground to form the buffer indicated by 434 as a whole. The base of transistor Q21 is connected to the collector of exposed photodiode 430. The base of the load transistor Q22 is a fixed voltage V_BConnected to. The output of buffer 434 is connected to the optical storage capacitor 304 via transistor Q23. The base of transistor Q23 is driven by sample signal 314, allowing transistor Q23 to function as switch 316. The anode of the shielded photodiode 432 is connected to ground and the cathode is V via transistor Q24._DDConnected to. The base of transistor Q24 is driven by the reset signal 308, allowing transistor Q24 to function as switch 382. Transistors Q25 and Q26 together form the buffer indicated by 436, insulating the output from the shielded photodiode 432 in the same way that the buffer 434 insulates the exposed photodiode 430. Transistor Q27 connects the output of buffer 436 to the noise storage capacitor 388. The base of transistor Q27 is driven by sample signal 314, allowing transistor Q27 to function as switch 386. Normally, the optical storage capacitor 304 and the noise storage capacitor 388 are 2pF. The lamp capacitor 324 is typically 10pF and is V via transistor Q28._DDWill be charged up to. The base of transistor Q28 is driven by the reset signal 328, allowing transistor Q28 to function as switch 330. The lamp capacitor 324 has an approximate constant current I of 0.01 μA through the current source 326 when transistor Q28 is off._RIs discharged at.

When the lamp voltage 322 falls below a preset voltage, the inclusion of a circuit configuration that suppresses the output improves the power-up response of the sensor and extends the effective dynamic range of the sensor. The optical-pulse circuit 214b sets the lamp voltage 322 to the initial set voltage (V)._INIT) Includes a comparator 438 to compare with 440. The output 42 of the comparator is ANDed with the exclusive OR output 396 by the AND gate 444 to generate the output 446 of the AND gate. During operation, if the ramp voltage 322 drops below the default voltage 440, the output 446 is deasserted (ie, kept at a low logic level). By using the comparator 438 and the AND gate 444, it is guaranteed that the output 446 is not asserted regardless of the state of the optical-pulse circuit 214b following the power-up. In a preferred embodiment, the initial set voltage is 0.45V.

Sensor logic 306 generates control signals 308, 314, 328 based on integrated pulses 212 that can be generated internally or supplied from an external source. Buffer 447 receives the integrated pulse 212 and produces sample control 314. An odd number of consecutively connected inverters, commonly referred to as inversion column 448, receive sample control 314 and generate reset control 308. A second set of odd number of inverting units in continuous connection, generally shown as inverting sequence 449, receives a reset signal 308 and produces a ramp control signal 328. The circuit shown in FIG. 12 has a resolution of at least 8 bits and a sensitivity of approximately 1 V per lux second. The maximum output pulse duration 420 is independent of the integration time duration 346 provided by the duration of the integration pulse 212.

It is assumed that the optical signal 318 over the capacitor 304 and the noise signal 390 over the capacitor 388 of FIG. 12 can be input to the differential operational amplifier 321 (FIG. 12A). The output of the differential amplifier 321 is an analog signal that represents the difference between the optical signal 318 and the noise signal 390. This circuit can be used when the control logic 66 includes an analog-to-digital converter capable of converting these digital signals into analog signals.

Next, with reference to FIGS. 13-16, various embodiments for packaging, output, and control of the optical sensor are shown. Each embodiment can include the light-pulse circuit described above. In FIG. 13, the optical sensor package 450 has a supply voltage V._DD, Ground, sensitivity control signal 452, and output signal 454 accepts four pins. The sensitivity control signal 452 can be an integrated pulse 212 used in the optical-pulse circuits 214, 214a, 216b to generate an output 398, which is sent out as the output signal 454. In Figure 14, the optical sensor package 456 is V_DD, Ground, and only three pins for the combination of sensitivity control and output coupled signal 458 are required. The combined signal 458 can be the interconnect signal 186 as described above. In Figure 15, the optical sensor package 460 has an output signal of 454, ground, and V._DDAnd three pins for the combination of sensitivity control coupling signal 462. As is well known in the art, the combined signal 462 utilizes a filter to supply voltage V._DDAnd the sensitivity control signal 452. For example, a low-pass filter and a high-pass filter can be used to separate these signals. In FIG. 16, the optical sensor package 464 is V._DDIt contains three pins for, ground, and output signal 454. The sensitivity control signal 452 is generated within the optical sensor package 464 as described below.

Next, referring to FIG. 17, a block diagram of the sensor logic for measuring the integrated time period signal in the sensing circuit 15 is shown. The sensor logic 306 can include a self-propelled counter 470 driven by an internal oscillator 472. Counter 470 can have taps, one of which is indicated by 474 and is connected to various counter bits. For example, one tap 474 can connect to the nth bit, the next tap 474 to the n + 2nd bit, the next tap 474 to the n + 4th bit, and so on. This gives each successive tap a pulse for a time period four times longer than the previous tap 474. The sensor control signal generator 476 controls the switch 478 to determine which tap 474 is used to generate the integrated pulse 212. Normally, the sensor control signal generator 476 repeatedly performs each tap 474 in order. The sensor control signal generator 476 then uses the integrated pulse 212 as described above to generate control signals such as the reset signal 308, the sample signal 314, and the lamp control signal 328. If the sensor internally generates an integrated pulse to change the sensor sensitivity, the control logic cannot change the integrated time period, but will receive a short output pulse, a medium output pulse, and a long output pulse from the sensor. It will be appreciated that the light levels measured accordingly can be determined to be bright, medium, and low light levels.

An alternative embodiment of the sensor circuit 15 is then shown with reference to FIG. 18, where optical transducers with different effective areas are used to achieve variable sensitivity. Instead of or in addition to changing the integration time, a pair of exposure transducers 178 and shading transducers 216 with different effective areas can be used. When photodiodes 430, 432 are used as optical converters 178, 216, the effective area is the area of the photodiode collector. A small exposure transducer 490 produces an electric charge, which is converted to voltage by the optical-voltage circuit 492. The optical-voltage circuit 492 can be implemented using switches 310, 316, and an optical storage capacitor 304 as described above. The charge generated by the small shading transducer 494 is converted to voltage by the noise-voltage circuit 496. The noise-voltage circuit 496 can be implemented using switches 382, 386 and noise storage capacitors 388 as described above. The output of the optical-voltage circuit 429 and the output of the noise-voltage circuit 496 are small over the integration time period, which is converted to pulses by the voltage-voltage circuit 498 and subtracted the charge due to the noise integrated by the small shading transducer 494. It has a width based on the charge accumulated by the exposure transducer 490. The voltage-pulse circuit 498 can be implemented using comparators 320, 392, capacitors 324, current sources 326, and gate 396 as described above. The medium exposure transducer 500 has a larger effective area than the effective area of the smaller exposure transducer 490, resulting in increased sensitivity. For example, if the effective area of the medium exposure transducer 500 is four times larger than the effective area of the small exposure transducer, then the medium exposure transducer 500 is four times as large as the small exposure transducer 490 for light 176. It becomes sensitivity. The medium shading transducer 502 has the same effective area as the medium exposure transducer 500. Additional optical-voltage circuit 492, noise-voltage circuit 496, and voltage-pulse circuit 498 are moderate over the integration time period. Generates a noise-corrected output pulse with a width based on the light 176 incident on the exposure transducer 500. Similarly, the large exposure transducer 504 and the large light-shielding transducer 506 provide higher sensitivity than the medium exposure transducer 500 and the medium light-shielding transducer 502 by having a larger effective area.

Switch 508, under the control of sensor logic 306, sets which voltage-pulse circuit 498 output is used for output signal 454. The output signal 454 can be selected based on the signal generated within the sensor logic 306, or it can also be based on a signal provided from outside the sensor logic 306. In particular, the control signal is provided by control logic 66, which controls switch 508 to connect to output 454 to select one of a small converter, a medium optical converter, and a large converter. be able to.

In an alternative embodiment, only one shading transducer 216 is used. The output of the shading transducer 216 is adjusted in proportion to the various effective areas of the exposure transducer 178 before the noise-voltage circuit 496. The embodiment shown in FIG. 18 has three pairs of exposure transducers 178 and shading transducers 216, but those skilled in the art will appreciate that any number of pairs may be used.

Next, with reference to FIG. 19, a block diagram illustrating an increase in dynamic range using optical transducers with different apertures is shown. Instead of or in addition to specifying the integration time period, the exposure transducer 178 having the same effective area can each have a different aperture incoming area through which the light 176 passes. Various apertures can be generated using a partial shield 520 that prevents the light 176 from reaching a portion of the exposure transducer 178. Each exposure transducer 178 produces a charge that is converted to voltage by the corresponding light-voltage circuit 492. Switch 522 under the control of sensor logic 306 selects which optical-voltage circuit 492 output is connected to voltage-pulse circuit 498. The voltage-pulse circuit 498 produces a noise-corrected output signal 454 sensed by the shading transducer 216 and processed by the noise-voltage circuit 496. The sensor logic 306 can select the output of the optical-voltage circuit 492 based on the internally generated control signal or the control signal received from the control logic 66.

In an embodiment using a plurality of converters 178, 490, 500, 504, the sensing circuit 15 detects incident light within a target spatial distribution. Each transducer 178, 490, 500, 504 observes the same target spatial distribution. Therefore, the control logic 66 generates at least one device control signal 166 based on the optical signal 164 without mapping the optical signal 164 to a region within the target spatial distribution.

Then, with reference to FIG. 20, a transducer that can be used to obtain various sensitivities is shown. The photodiode represented by 530 as a whole is formed by an n-type diffuser 532 in a p-type substrate 534. The light 176 incident on the photodiode 530 produces a charge 536, which can be stored in the photodiode well 538 under the n-type diffuser 532. The photodiode 530 has a unique photodiode capacitance C._PDHave. Further, the floating diffusion portion 540 is formed by diffusing the n-type material on the substrate 534. The floating diffuser 540 has a reset voltage V via the transistor Q20._RESETConnected to. The gate of transistor Q20 is connected to the reset signal 308 under the control of sensor logic 306. The floating diffuser 540 is also connected to the input of buffer 542. The output of buffer 542 is the output V of the converter._OUTWill be. The floating diffuser 540 forms a diffuser well 544 formed in the region of the substrate 534 when the reset signal 308 is asserted. The floating diffuser 540 has a unique floating diffuser capacitance C._FDHave. The transmission gate 546 is positioned between the diffuser 532 and the floating diffuser 540. The transmission gate 546 has a voltage V to form a transmission well 548 underneath._TGIs held in. The transmission well 548 has a shallower depth than the photodiode well 538 and the diffuser well 544. Transmission gate 546 has a unique transmission gate capacitance C_TGHave.

When the reset signal 308 is asserted, the floating diffuser 540 is V._RESETAnd the charge is removed at the diffuser well 544. Further, when the charge is reset at the diffuser well 544, any charge 536 of the photodiode well 538 that exceeds the depth of the transmission well 548 flows through the transmission well 548 and through the floating diffuser 540 and is removed. .. During the optical integration time period, the reset signal 308 is non-assertive and floats the voltage of the floating diffuser 540 based on the amount of charge in the diffuser well 544. When the light 176 hits the diffuser 532, an electric charge 536 is generated. The charge 536 of the photodiode well 538 up to the level of the transmission well 548 was not removed by the charge reset, so the additional charge 536 generated by the incident light 176 would pass from the photodiode well 538 through the transmission well 548. It flows into the diffuser well 544. At charge level 550 below transmission well 548, only diffuse well 544 is filled with charge 536. Therefore, the voltage of the floating diffuser 540 is the capacitance C of the floating gate._FDIs inversely proportional to. If sufficient charge 536 is generated and exceeds the level of transmission well 548, such as level 552, to fill diffuse well 544, then diffuse well 544, transmission well 548, and photodiode well 538 are all charged 536. It is filled. Therefore, the voltage of the floating diffuser 540 is the capacitance C of the floating diffuser._FD, Transmission gate capacitance C_TG, And photodiode capacitance C_PDIs inversely proportional to the sum of. As a result, the optical sensor will have a sensitivity determined by the magnitude of the resulting optical signal.

Next, referring to FIG. 21, a graph of the output potential is shown as a function of the incident light stored in the transducer of FIG. The curve shown by 554 as a whole is the converter output V as a function of the light 176 incident on the diffuser 532 and, in some cases, the floating diffuser 540 over the integration time period._OUTIs shown. During the steep slope portion 556, the charge 536 accumulates only in the diffuser well 544. The conversion gain is the capacitance C of the floating diffuser._FDThe photodiode 530 appears to have high sensitivity to incident light 176, as it is based solely on. During the shallow portion 558, charge 536 is stored in diffuser wells 544, transmission wells 548, and photodiode wells 538. The conversion gain here is the capacitance C_FD, C_TG, And C_PDThe photodiode 530 seems to be less sensitive to the incident light 176 because it is determined by the parallel combination of. Voltage V_RESETAnd V_TGBy adjusting, the refraction point 559 between the steep slope portion 556 and the shallow portion 558 can be shifted to change the dynamic range. For example, the maximum voltage amplitude of the floating diffuser 540 is 1 volt, C._FDAgainst C_FD, C_TG, And C_PDWhen the ratio to the sum of is set to 1: 100 and the refraction point 559 is set to 0.5 volt, the dynamic range of the photodiode 530 increases to about 50 times the dynamic range of a similar photodiode without dual capacitance.

Next, with reference to FIG. 22, a schematic diagram showing a photodiode converter incorporating an anti-blooming gate is shown. Anti-blooming gate 560 has diffuser 532 and V_DDIt is formed between the source voltage spreader 562 and the connected source voltage spreader 562. The anti-blooming gate 560 has an anti-blooming voltage V_ABIt is connected to. The anti-blooming gate 560 forms an anti-blooming well 564 between the photodiode well 538 of the substrate 534 and the source diffuser well 566. Anti-blooming voltage V_ABIs the transmission gate voltage V_TGSmaller than well 564 and shallower than transmission well 548 for anti-blooming well 564. When the charge buildup generated by the photodiode 530 exceeds the charge level 568, which corresponds to the depth of the anti-blooming well 564, the excess charge passes under the anti-blooming gate 560 and is removed by flowing to the source voltage spreader 562. Will be done. Anti-blooming gate 560 has an output voltage of V_OUTPrevents the light-pulse circuits 214, 214a, 214b from dropping below the level detectable by the comparator 320.

Further details regarding the operation of the processing circuit 66, the sensing circuit 15, and the optical-pulse circuits 214, 214a, 214b are disclosed in US Pat. Nos. 6,379,013 and 6,359,274 referred to above, and these disclosures. The whole is incorporated herein by reference.

Although specific preferred embodiments of sensing circuits have been disclosed above, the term "sensing circuit" as used herein is not limited to any of these structures, but any form of optical sensor. Can also be included. Similarly, although the "support structure" has been described above as a lead frame or part thereof, the support structure may be any structure capable of supporting and encapsulating the sensing circuit.

The sensor device of the present invention can be used in many applications in which a conventional sensor device is used. U.S. Pat. No. 6,379,013, assigned to the assignee of the invention, discloses various automotive uses of such sensors, the entire disclosure of which patent is incorporated herein by reference.

Figures 23A-23D, 24 and 25 show some of these automotive applications. Specifically, the rear view mirror assembly 1500 is shown in FIGS. 23A-23D, which includes ambient light sensed by a front facing ambient sensor 50a (FIG. 23B) and a rear facing glare sensor 50b (FIG. 23A). As a function of the level of, an electrochromic rear view mirror 1502 with reflectance controlled by processing circuits 66 (FIGS. 5 and 24) is incorporated. One or both of the sensors 50a and 50b can have any of the configurations shown in FIGS. By utilizing a sensor having the configuration shown in any of FIGS. 1 to 4, the horizontal field of view can be expanded or contracted with respect to the vertical field of view as desired for a particular sensor.

As shown in FIGS. 23B-23D, the rear view mirror can further include a skysensor 50c directed to the sky. Such skysensors serve a headlamp control system that detects the tunnel, which ensures that the headlamps are turned on when the vehicle enters the tunnel and turned off when the vehicle exits the tunnel. Further, it may be advantageous for the sky sensor 50c to use the configuration shown in FIG. 1 and described above. Skysensor 50c is coupled to processing circuit 66 (FIGS. 5 and 24), which in turn is coupled to headlamp control unit 1512 for ambient light levels and skylight sensed by sensors 50a and 50b. Vehicle headlamps can be turned on and off according to the level. The headlamp control system further includes an image sensor 1515 that controls the brightness of the high beam headlamps and / or senses an image in front of the vehicle to activate or aim the headlamps or other external lights 1516. The beam pattern generated by the external light can be modified based on the light source detected by the image sensor 1515. An example of such a head lamp control system is the present invention of the name "SYSTEM FOR CONTROLLING EXTERIOR VEHICLE LIGHTS" filed by Joseph S. Stam et al. On March 5, 2001. It is disclosed in US Pat. No. 6,587,573 transferred to the transferee, the entire disclosure of which is incorporated herein by reference. It also uses the outputs of sensors 50a, 50b, and / or 50c to control other vehicle lights, such as the vehicle interior lights 1518, and more specifically in various displays of instrument panels and other vehicle accessories. The brightness of the indicator light can be controlled.

Similarly, as shown in FIGS. 23B-23D, two or more additional sensors 50d and 50e can be utilized to detect the sunshine load. The sunshine load sensors 50d and 50e are directed above the vehicle and further slightly to different sides of the vehicle to detect if the sunshine load on one side of the vehicle is greater than on the other side of the vehicle. To do. The processing circuit 66 (FIGS. 5 and 24) is coupled to the sunshine load sensors 50d and 50e and further to the vehicle air conditioning system 1530 for fan speed and fan speed and based on the light level detected by the sunshine load sensors 50d and 50e. / Or adjust the temperature settings on each side of the vehicle. The sunshine load sensors 50d and 50e can also be configured as described above and shown in FIGS. The light level sensed by any one of the sensors described above can be used to control some aspect of the operation of the air conditioning system 1530. For example, a skysensor 50c and a perimeter sensor 50a can be used to detect the approach of a tunnel, which turns on the headlamps and puts the air conditioning into recirculation mode.

FIG. 25 shows yet another automotive application for utilizing the sensor structure of the present invention. Specifically, FIG. 25 shows a moisture sensing system that detects moisture on the windshield of a vehicle (ie, rain, cloudiness, fog, frost, and snow). The system includes a light source such as LED 1540 and a sensor 50f. The light emission emitted from the LED 1540 (ie, visible light, or infrared, or ultraviolet light) enters the windshield 1550, where it is internally reflected and exits, incident on the sensor 50f. When moisture is on the windshield, the light from the LED 1540 does not reach the sensor 50f and the processing circuit 66 (FIGS. 5 and 24) controls the vehicle windshield wiper 1545 and / or vehicle air conditioning via the wiper control unit 1546. Activate the windshield wiper of system 1530.

The above embodiments of automotive applications have been described as being placed in a rear view assembly, but some of the above applications, in whole or in part, are vehicles such as vehicle instrument panels, windshields, sun visors, etc. It should be appreciated that it can be mounted elsewhere in the vehicle or in vehicle accessories, or in an overhead console located on or near the headliner or windshield. Moreover, the sensors of the present invention can be used in any other non-automotive application, and the broadly defined invention is not limited to any of such applications.

Preferred configurations of the rear view assembly 1600 and the glare sensor subassembly 1650 of the present invention are shown in FIGS. 26-39 and are further described below.

As shown in FIGS. 26 and 27, the rear view assembly 1600 illustrated as an electrochromic rear view mirror assembly includes a housing 1610 having a rear casing 1612 and a bezel 1614, the rear casing 1612 and the bezel 1614 being fixed together. It houses the electrochromic mirror element 1620 and the circuit board 1630 on which the glare sensor subassembly 1650 and the ambient light sensor 1670 (FIGS. 28B, 28C, and 28D) are mounted. The support plate 1680 can optionally be provided to support the circuit board 1630 and / or the electrochromic mirror element 1620 within the housing 1610. The electrochromic mirror element 1620 can be secured to the support plate 1680 using double-sided tape or a layer of adhesive, or as in the illustrated embodiment, the support plate 1680 is located on the opposite edge of the mirror element 1620. Can be snap-fitted around.

In the embodiments shown in FIGS. 26 and 27, a switch support 1690 supporting a pushbutton switch 1692 located along the bottom of the housing 1610 is included in the mirror assembly. A mounting socket 1695 (or mounting ball (not shown)) for engaging a ball (or socket) of a mirror mount (not shown) can also be incorporated within the housing 1610, with the housing 1610 relative to the mirror mount. To be pivoted in two dimensions.

The housing 1610 can accommodate many other components well known in the art. In the embodiments shown in FIGS. 26 and 27, a large aperture 1615 for mounting the map light assembly 1684 is provided on the rear casing 1612. Such a map light assembly can include an LED subassembly (not shown), a heat sink / mounting plate 1685, a reflector 1687, and a lens 1689. Examples of such maplight assemblies are disclosed in US Pat. No. 6,670,207, the entire disclosure of which is incorporated herein by reference. There is also a smaller aperture 1617 that opens behind the rear casing 1612 (and in front of the vehicle), preferably configured by the method described above, and illuminates the ambient light sensor 1670 surface-mounted on the back surface 1631 of the circuit board 1630. Can pass through. Secondary optics (not shown) may be provided over a small aperture 1617 to act as a diffuser and / or lens.

Figures 28A-28E show various diagrams of the structure in which the circuit board 1630 and the support plate 1680 are combined. As shown, the support plate 1680 can include elastic tabs that allow the circuit board 1630 to snap fit into place and be secured by the support plate 1680. As shown, the sensors 1652 and 1670, as well as the secondary optics 1660, can all be secured to the circuit board 1630 before being mounted within the housing 1610. By configuring these elements to be pre-mounted on the circuit board, they can be tested on the circuit board prior to assembly within the mirror assembly. This reduces disposal costs when the sensor or circuit configuration does not operate at the desired performance level.

Figures 29-39 show the glare sensor subassembly 1650 in more detail. As shown in FIGS. 29-39, the glare sensor subassembly 1650 includes a sensor device 1652 mounted on circuit board 1630 and a secondary optical element 1660. The circuit board 1630 includes a first hole 1632 through which the sensor device 1652 extends so that the sensor device can be surface mounted on the back surface 1631 of the circuit board 1630 to further detect light coming from the rear of the vehicle. become. This makes it possible to surface mount both the ambient light sensor 1670 and the glare sensor device 1652 on the same surface (1631) of the circuit board 1630. The circuit board 1630 further includes a pair of holes 1634 through which the corresponding pair of elastic legs 1662 of the secondary optics 1660 extend. Hole 1634 allows the secondary optical element 1660 to snap fit to the circuit board 1630 so as to extend forward of the glare sensor device 1652, as shown in FIG. FIG. 30 shows the arrangement of the glare sensor device 1652 with the secondary optical element 1660 removed from the circuit board 1630.

Returning to FIG. 27, it can be seen that the glare sensor subassembly 1650 is mounted on the circuit board 1630 so as to be optically aligned with the region 1622 of the mirror element 1620. Region 1622 can be a region in which the reflective layer of the mirror element has been partially or completely removed so that light can travel through the mirror element to the secondary optics 1660 and then to the glare sensor device 1652. .. U.S. Pat. No. 6,356,376 discloses an electrochromic mirror element in which a glare sensor device is mounted behind an area where part of the reflective layer has been removed. The entire disclosure of this patent is incorporated herein by reference. Alternatively, the region 1622 can be a region of a reflective layer that is partially reflective and partially transparent (ie, "semi-transparent"). For this, the entire reflective layer may be semi-transparent. Examples of semi-transmissive electrochromic mirrors are disclosed in US Pat. No. 6,356,376, the entire disclosure of which is incorporated herein by reference. This region 1622 can be formed by masking the back surface of the substrate while the reflective layer is deposited. A layer of a noble metal such as indium tin oxide or ruthenium can be applied over the region 1622 to provide conductivity throughout the region 1622, allowing the electrochromic medium to uniformly darken the entire mirror element.

Secondary optics 1660 are shown in detail in FIGS. 32-39. The secondary optical element 1660 is so called because its optical system is an auxiliary of the optical system incorporated in the sensor device 1652. The secondary optics 1660 can simply be a diffuser, or can act as an alternative or additional lens. In the preferred embodiment shown in FIGS. 32-39, the secondary optics 1669 functions as a lens, but can be textured on one or both sides, or a diffuser is added to the material used to make up the element 1660. It will be appreciated that it can be incorporated to diffuse the light passing through it.

Secondary optics 1660 includes a relatively flat substrate 1664 with a front surface 1665 and a back surface 1666. A pair of elastic leg portions 1662 extend rearward from the two sides of the substrate 1664. Apron 1667 extends rearward from another side of substrate 1664. The apron 1667 does not extend as far back as the leg 1662, thereby limiting the insertion depth of the circuit board 1630 into the hole and maintaining the distance between its back surface 1666 and the front surface of the glare sensor device 1654. ..

In the illustrated embodiment, the first lenticular lens 1668 can be provided on the front surface 1665 of the substrate 1664 and the second lenticular lens can be provided on the back surface 1666. The first lenticular lens 1668 includes a plurality of parallel elongated first small lenses 1668a, and the second lenticular lens 1669 includes a plurality of parallel elongated second small lenses 1669a. The first small lens 1668a extends perpendicular to the second small lens 1669a to allow different focal lengths in the horizontal and vertical planes. By forming different focal lengths in these different planes, the field of view of the glare sensor can be different in the vertical and horizontal directions. As a result, the field of view is made to attempt to limit the field of view to the view seen through the rear window, especially without including other parts of the cabin such as the rear seats that should be present when the vehicle is adopting theater seats. It can be scaled up and down. As used herein, the term "anamorphic lens element" refers to a lens element that has different focal lengths in different planes and provides an aspheric or aspherical field of view. Although the two vertical lenticular lenses have been described above, other forms of anamorphic or spherical lenses can also be used. Such lenses can be plano-convex, biconvex, cylindrical, spherical, parabolic, elliptical, or biradial, in the form of microgroove lenses such as single lenses, lenticular lenses, or Fresnel lenses. be able to. The particular form of the lens used (if any) will depend on the particular application. By including such a lens in the secondary optics, the same glare sensor device 1652 can be used regardless of the vehicle being incorporated, but the secondary optics 1660 is selected and incorporated for a particular type / model of vehicle. be able to.

Although the configuration of the glare sensor device 1652 and the ambient light sensor 1670 has been described so as to include the integrated lens structure 20 shown in FIGS. It will be understood that you can. For example, the encapsulant can be shaped to define a spherical lens or an anamorphic lens such as a cylindrical lens or biradial lens shown in FIGS. 40-45 and described below.

A sensor device 1750 configured according to a second embodiment of the present invention is shown in FIG. The sensor device 1750 includes a support structure such as a printed circuit board or a lead frame 1712, a sensing circuit 15 mounted on the support substrate to sense light radiation, which is preferably visible light, and sensing on the support structure. Includes an encapsulant 1762 that encapsulates circuit 15. Generally, the encapsulant 1762 includes an integral lens 1720 with an anamorphic surface 1722 that provides different lateral fields of view. According to the first embodiment, the anamorphic surface 1722 is biradial. For example, the design can have a field of view with a nominal 90 degree angle of view in direction 1725 and a nominal 45 degree angle of view in direction 1726. For example, a toroidal lens surface 1722 with a radius of 1.5 mm in the direction indicated by 1732 and a radius greater than that indicated by 1731 can be generated by sweeping the center of the curve 1732 around an arc with a radius of 1 mm. .. A lens formed by a toroidal surface 1722 has a focal length of approximately 4.5 mm in a plane that traverses the lens along the smaller radius of the lens and a focal length of approximately 7.5 mm in a plane that traverses the lens along the largest radius. Have a distance. The active sensing area 57 of the sensing circuit 15 is small (ie 1mm).²It has a surface area of less than) and is located in the center of the upper surface of the sensing circuit 15. Preferably, the active sensing region 57 has a diameter of, for example, 100 microns and a diameter of about 0.03 mm.²Has an area of. The surface 22 can be in many forms and does not have to be toroidal. For example, curve 1732 can optionally be any aspherical shape optimized for some aspect of lens performance. Thus, the shape 1732 can optionally rotate in the same manner as the toroidal surface 1722 to form a surface of revolution in the opposite direction, or can be swept along other curves. In the more general case, the surface profile does not even need to be circular in either direction. Surfaces that serve the purposes of the specification of the present invention are those that perform the desired function and generally have a larger radius of curvature as measured at the intersection of planes approximately parallel to the direction of the widest field of view. As described below in connection with the second embodiment of the present invention, the integral lens can have a cylindrical surface.

For lenses with surface profiles with different radii on different reference planes, leifangs projected onto the lens from within these different planes are approximately in focus at various distances from the lens surface. The position of the sensing area 57 with respect to the various focal lengths of the lens strongly influences the shape obtained as a result of the sensitivity profile of the sensor response. In general, it is preferable to position the active sensing surface 57 closer to the lens than the closest distance to the point where the strong focusing property is present. In the above embodiment, this would be closer than the nominal focal length of 4.5mm resulting from a lens radius of 1.5mm. Placing the sensor plane in front of the focal length has the defocusing effect of expanding the response profile of the reference plane to which a particular focus is applied. As the ratio of the distance from the lens to the active surface of the sensor to the focal length of a particular focal length decreases, the optical gain in the corresponding direction generally decreases and the width of the response profile in the corresponding direction increases. The radius of curvature and the focal length obtained in a plane parallel to direction 1725 is longer than the focal length corresponding to direction 1726, so the ratio of the distance from the lens to the sensor to the longer focal length is smaller and the corresponding response profile is higher. Wider, but the contribution of the sensor to the overall optical gain is significant but smaller. This is consistent with the desire to have a broader response profile in the direction indicated by 1725.

To illustrate the effect of positioning the active sensing region 57 of the sensing circuit 15 closer to the lens than the focal point, light beam tracing of two different photosensor configurations is shown in FIGS. 41A and 41B. In both devices shown in FIGS. 41A and 41B, the integrated lens / encapsulant has a length along the 4 mm optical axis and the active sensing area 57 of the sensing circuit 15 is located 3 mm behind the front of the integrated lens. doing. The first photosensor device shown in FIG. 41A has an integrated lens, is a plane on which a cross section is taken, and has a radius of 1.25 mm. On-axis and off-axis light sources of +10 and -10 degrees were used to orient light with a wavelength of 550 nm into the lens. The optical sensor device shown in FIG. 41B is similar to that shown in FIG. 41A, except that the radius of the integrated lens is 1.45 mm and therefore the focal length of the lens is increased. However, the sensing circuit of the second photosensor device is maintained at 3 mm from the lens. Comparing the two devices, it is clear that in the first photosensor shown in FIG. 41A, only the light from the light source position on the axis is incident on the active sensing region of the sensing circuit 15. In this configuration, the first photosensor device shown in FIG. 41A is essentially invisible to off-axis light. However, in the active sensing region of the sensing circuit 15 of the second photosensor device shown in FIG. 41B, there is light from both +10 and -10 degrees off-axis positions. Therefore, the second photosensor device shown in FIG. 41B is more sensitive to off-axis light than the photosensor device shown in FIG. 41A.

In order to further expand the response profile in almost all directions, the diffusing agent can be added to the lens material in proportions experimentally determined to produce the desired effect, or surface treatments such as texturing. It can be applied to the lens surface. The texturing of the lens surface is preferably provided by duplication of the mold surface, but can also be produced by a secondary step such as coating or bombarding with sandblasting or some other grinding agent. In transfer molding techniques, textured surfaces are often preferred, but in encup molding techniques, textured surfaces may have mold release problems. Therefore, when selecting a technique for adding diffusion, it is necessary to consider compatibility with the manufacturing process. In a process called the encup process, the fluid plastic lens material is dispensed into a flexible mold cup and the finished lead frame assembly is lowered into the filling material. To complete the assembly, the material is cured, the finished parts are removed from the mold and the individual parts are separated from each other. Thus, for example, by adding a diffusing agent to the encapsulants of the photosensors shown in FIGS. 41A and 41B, the angular response profile is increased so that off-axis light is spaced away from the active sensing region of the sensing circuit. Can deal with the burning effect.

As will be appreciated by those skilled in the art, the second optical sensor shown in FIG. 41B is shown in FIG. 41A, based on the fact that the sensing circuit is located at a distance from the lens that is shorter than the focal length of the lens. It is necessary to add less diffusing agent than the optical sensor. Furthermore, it will be understood that the optimum amount of diffusing agent and the optimum positioning of the sensing circuit within the encapsulant will depend on the particular application in which the optical sensor is adopted. In general, an appropriate distance between the lens surface and the active sensing area of the sensing circuit provides a near-desired field of view for the light sensing device, resulting in the addition of a diffusing agent to the encapsulant to reduce shadowing caused by lens defects. It should be selected so that the field of view can be expanded to the desired value.

Many balances between offset effects can be maintained throughout the design. In this one balance, the sensor is placed farther from the lens, closer to the focal point, the profile can be narrowed in approximately both directions, and a controlled amount of diffuser or surface treatment agent is added to diffuse. It can be increased and the profile expanded to the desired degree. This is especially advantageous when defects must be tolerated on the lens surface of the sensor. When the lens is used at its focal point, the light from the light source at the distal point can be oriented from most of the lens surface to the sensing surface. In such a case, even a relatively large scratch on the lens may have a minor effect on the resulting device performance. In contrast, if the lens surface is flat rather than curved, then nearly parallel rays from the light source at the distal point that hits the sensor will pass through a surface area that is about the same size as the active sensing area itself. Become. On an active sensing surface with a diameter of only 100 microns, dirt or scratches on a plane of similarly small size block or scatter almost all of the light from a point source, creating virtually blind spots in the sensor's field of view. there is a possibility. On the bi-radial surface, when using strong defocus, the situation can be much closer to a plane than in the focused lens embodiment. In such cases, very small defects can block or scatter light from a small area of light source, sometimes creating what is effectively a blind spot in the field of view of the sensor. Moving the sensor closer to focus increases the surface area of the lens that focuses light from a small distal area on the sensor, and the diffuser reduces the shadow cast by the scratch. Both of these effects serve to mitigate the "blind spot" problem, thus allowing the use of such small sensing circuits.

The lens portion 1720 of the encapsulant 1762 is fused to a nearly cylindrical portion 1713 that encloses a portion and top of the lead frame 1712. Lip 1714 can be used for component alignment in applications. The lead frame 1712 has legs 1780, 1782, and 1784 that support the components and serve to make electrical connections. The sensor chip 15 is joined to the leg portion 1782 with conductive epoxy, and the lead wires 1723 and 1724 are electrically connected to the leg portions 1780 and 1784, respectively. In applications, the three leads connect the component to the associated electrical circuit.

FIG. 42 shows a sensor device 1750 that is surface-mounted on the front-facing surface of the circuit board 1630 and acts as a glare sensor. As described above, it is preferable to surface mount the sensor device rather than using through-hole mounting technology. Further, it is desirable that the glare sensor and the surrounding sensor are mounted on the same surface of the circuit board. As shown in FIG. 42, the sensor device 1750 can be mounted in a hole in the circuit board 1630 to receive light from the rear of the vehicle through the mirror element 1620. This particular sensor offers an advantage in that the integrated lens 1720 is anamorphic, so it may not be beneficial with separate secondary optics.

FIGS. 43 and 44 show a sensor device 1750 configured according to a third embodiment of the present invention. As is clear from the comparison of each figure, the third embodiment differs from the second embodiment in that the integral lens 1720 of the encapsulant 1762 has a cylindrical surface 1752 instead of a biradial surface. Lens 1720 can have any desired radius and length, eg, a radius r of 1.25 mm (FIG. 44) and a length L of 5 mm. When mounted on a vehicle with the vertical axis of the cylindrical lens 1720 approximately perpendicular to the horizontal axis, horizontal compression without the corresponding vertical compression is achieved. This allows observation of large areas of the sky without sensing the corresponding large areas of the ground, vehicle roof, or vehicle hood when the sensor is used for skysensors. Conversely, when mounted horizontally, a wide horizontal field of view input can be obtained. This feature can be advantageously utilized to implement a glare sensor, as described in more detail below.

FIG. 45 shows a sensor device 1800 configured according to a fourth embodiment. The sensor device 1800 is first and second in that the encapsulant is formed from two or more different functional zones 1802 and 1804 and has a transition region 1806 between the zones 1802 and 1804. Different from the embodiment. Different parts of the encapsulant can perform different functions than the other parts of the encapsulant, so that the first zone 1802 has at least one different feature from the second zone 1804 and is identified. Two separate functional zones 1802 and 1804 are provided based on the recognition that the performance of the functions performed by these zones is optimized. For example, the first zone 1802 needs to at least partially transmit the wavelength of radiation that will be sensed by the sensing circuit 15, while the second zone 1804 does not need to transmit such a wavelength. This allows the sensor device of the present invention to take advantage of the special advantages of encapsulating high performance power semiconductors and transfer molding compounds in the second zone. These characteristics include relatively low coefficient of thermal expansion, relatively high thermal conductivity, relatively high Tg, relatively high specific heat, relatively low permeability to oxygen, gas or water vapor, and relatively high physical strength characteristics. And can be included. The compounds used to package or pot many high power non-optical electrical devices are significantly superior to those previously used for conventional sensors in many of these categories. One of the main reasons for this disparity is that the high performance material described is an opaque mixture that does not transmit the radiation flux normally sensed by the sensor device. The impermeability of these functionally attractive materials is inherently associated with their favorable properties (eg, by additives of minerals, metals, and metal oxides that enhance performance), and therefore these. The material has never been considered for use in sensor components due to its impermeable properties. However, the use of such materials needs to be permeable.

The first zone 1802 of the encapsulant 1762 is preferably a substantially transmissive material in order to maintain optical performance. Optionally, the first zone 1802 can be partially diffused. The first zone 1802 may be formed of any conventional transmissive encapsulant commonly used for sensors or LEDs. The first zone 1802 of the encapsulant 1762 covers, wraps, protects, and supports the sensing circuit 15, die adhesive (if any), and any wire bond 1723 and 1724 connected to the sensing circuit 15. It is preferable to do so.

The first zone 1802 of the encapsulant 1762 can consist of two or more portions, the innermost of which is pre-applied to the sensing circuit 15 prior to the first step of molding the encapsulant of the present invention. Silicone or silastic glob top (not shown). This innermost portion of the first zone 1802 may be an alternative a high performance epoxy, silicone, urethane, or other polymeric material containing a semi-transparent or permeable additive or diffuser, in some cases. be able to.

The first zone 1802 of the encapsulant 1762 is preferably formed of a composition comprising an optical epoxy mixture that is substantially permeable to the radiation sensed by the sensing circuit 15. However, other permeable materials can also be used, which need not be permeable in the band outside the main zone of sensitivity of the sensing circuit 15.

The second zone 1804 of the encapsulant 1762 is preferably formed of a material that optimizes the function of that region of the encapsulant 1762. As mentioned above, the second zone 1804 does not have to be transparent. However, a specialized function of Zone 1804 is to minimize sudden failures, stresses, and accumulated fatigue from mechanical stresses that generally propagate to conductive reeds 1780, 1782, and 1784. More suitable materials for this purpose can be selected taking into account that they do not need to be permeable, but also higher strength including higher tension and compressive strength, adhesiveness, and / or cohesiveness. Can have properties.

Another function provided by the second zone 1804 of encapsulant 1762 is otherwise through the boundary between the second zone 1804 or encapsulant 1762 and the leads 1780, 1782, and 1784. It acts as a barrier to oxygen, molecular water vapor, or other reactants that may propagate upwards within the device. Therefore, the second zone 1804 contains oxygen, molecular water vapor, sensing circuits 15, die adhesives (if any), wire bonds 1723 and 1724, encapsulations of the lead frame surface coating, and other internal equipment components. , And other reactants should be effectively protected. The second zone 1804 of the encapsulant 1762 does not have to be permeable, so the second zone 104 shall consist of improved barrier properties compared to those present in conventional permeable encapsulants. Can be done.

The second zone 1804 can also have better thermal properties than the first zone 1802. To lower the thermal resistance of the device, the second zone 1804 is at least in the critical region of the device surrounding the conductors 1780, 1782, and 1784, and to some of the leads supporting the sensing circuit 15. It preferably has a high thermal conductivity in the bond. To maintain relatively high thermal resistance protection from soldering, the bottom of the second zone 1804 of encapsulant 1762 should be against the solderable part or the ends of the conductive leads 1780, 1782, and 1784. In the absence of isolation insulators (if any) or isolation insulators, they do not extend closer than the equivalence points on the leads that remain virtually out of contact with the molten solder during the process.

By forming the second zone 1804 of the encapsulant 1762 to have a high heat capacity, the second zone 104 helps to suppress transient temperature spikes during processing or operation. Also, by configuring the second zone 1804 to have a low coefficient of thermal expansion, sudden obstacles, stresses, and accumulated fatigue resulting from thermal expansion and contraction within the device are minimized.

The two zones can have different physical properties in order to achieve different functional properties for the first and second zones 1802 and 1804 of the encapsulant 1762. Such physical properties can be structural or compositional. Such different structural properties can be obtained by using the same general composition for both the first and second zones 1802 and 1804, but by varying the particle size or microstructural orientation within the two zones. Such structural properties can be modified during the molding process by differently treating this zone with annealing, radiation curing, or other radiation treatments. Further, the microstructural orientation can be changed by applying a magnetic field to one or more of the zones forming the encapsulant 1762.

When two different compositions are used to form the first and second zones 1802 and 1804, as described further below with reference to the treatment of the invention forming the preferred embodiments of the invention. The composition of the material is preferably suitable for molding in the same mold. By integrally molding the first and second zones 1802 and 1804, a cohesive bond can be formed at the transition portion 106 between the zone 1802 and the zone 1804. Such cohesive bonding improves the strength of the encapsulant as a whole, allowing oxygen, water vapor, or other reactants that may otherwise be present through the interface between Zone 1804 and Zone 1806. Desirable to prevent reaching the sensing circuit 15. In addition, such coagulation joins provide outer surface continuity. The compositions used in the first and second zones 1802 and 1804 should be partially intermixed at transition 1806. The transition portion 1806 can have a fairly narrow cross section of the encapsulant 1762, or be wider and larger if a composition gradient is formed using the compositions of the first and second zones 1802 and 1804. Can be done.

Another advantage of making the second zone 1804 of the encapsulant 1762 opaque is that all backscatter from any light emitting element mounted on the same housing or circuit board can reach the sensing circuit 15. It is low. Such backscattering can be a problem when the light emitting element is mounted in the same housing as the sensing circuit 15, and when such a sensor device is mounted in an automotive electrochromic rearview mirror assembly. apply. The opaque second zone 1804 also functions to enter the encapsulant of the sensor device, pass through the sensing circuit, and absorb the light traveling toward the circuit board on which the sensor device is mounted. This can be important when other sensors are utilized in the same housing or on the same circuit board.

The substrate epoxy used to form the second zone 1804 of the encapsulant 1762 is not only distinguishable in composition from the epoxy of the transparent lens used to form the first zone 1802, but in addition to this. Or, as an alternative, one or more physical properties (spectral transmission at the wavelength of interest, diffuse scattering properties at one or more wavelengths of interest, fine crystal structure, strength, thermal conductivity, CT_E, Tg, etc.). The transition zone 1806 between the first zone 1802 and the second zone 1804 can also occur in the transition boundary zone, which can be narrow (causing abrupt transitions due to characteristics) or wide (gradual depending on the characteristics). It may result in a transition or gradient). As mentioned above, the difference between lens epoxies and substrate epoxies is compositional and can be achieved by using a mixture of two different materials in the manufacturing process. As a result, the narrow transition boundary between Zone 1802 and Zone 1804 Zone 1806 is only slightly added by ensuring two formulations that are essentially immiscible, or before adding one material to the other. It can be obtained by pre-curing to or completely. The wide boundary zone 1806 ensures that the first material is not completely pre-cured prior to the addition of the second material, and that the formulation of the two materials allows some mixing at these boundaries. Can be obtained by doing.

If the distinction sought between the lens epoxy and the substrate epoxy is primarily a physical distinction rather than a compositional distinction, and if the above measures are inadequate, another means to achieve this. Can be used. For example, enhancement of material properties for a compositionally identical substrate epoxy moiety can be obtained by post-treating the substrate epoxy moiety after dispensing into a mold. The post-treatment in this case can be selective overheating (by setting a temperature gradient in the mold, or by using a layered oven or a layered heating air stream, etc.). Pretreatment in this case, additionally or as an alternative, is selective irradiation with zoned IR, UV, visible light, microwaves, X-rays, or other electromagnetic radiation sources, or E-beams or other particle beams. Can be. Similarly, by exposing all or part of the equipment material to an electric field, magnetic field, centrifugal / centripetal force, or gravity before, during, or after dispensing, some microstructural effects (particle migration, lamination, Orientation, size, agglomeration, etc.) can be given.

One material suitable for the first zone 1802 of encapsulant 17 is HYSOL® OS4000 permeable epoxy available from the Dexter Electronic Materials Division. A suitable material for the first zone 1802 of the encapsulant 1762 is HYSOL® EO0123 casting compound, also available from Dexter. Further details on the process of making such multi-zone encapsulants can be found in the name "RADIATION EMITTER DEVICE HAVING AN ENCAPSULANT WITH DIFFERENT ZONES OF THERMAL CONDUCTIVITY" filed by John K. Roberts et al. On April 13, 2001. It is disclosed in U.S. Pat. No. 6,521,916, which was assigned to the assignee of the invention of "Luminometer device with encapsulant with different zones", which discloses a similar encapsulant apart from its use with LEDs. doing. The entire disclosure of this patent is incorporated herein by reference.

Further details regarding the sensor device shown in FIGS. 40-45 are disclosed in US Pat. No. 6,679,608, the entire disclosure of which is incorporated herein by reference.

FIG. 46 shows a drawing illustrating an optical sensor device 1950 configured according to a fifth embodiment of the present invention. The photosensor device 1950 includes a housing 172 having a window 174 for receiving the light indicated by 570 for one light beam. The housing 172 can accommodate the power pin 180, the ground pin 182, and the signal pin 184. The semiconductor die 572 housed in the housing 172 incorporates the optical transducers 178 and 216 and related electronic devices as described above. Pins 180, 182, 184 can be wire-bonded to die 572, as shown by wire 574 to power pin 180 and wire 576 to signal pin 184, or as shown for ground pin 182. It may be joined directly to the die 572.

The housing 172 can be the same type of encapsulant used to form a three-terminal light emitting diode (LED). The preferred model is usually referred to as the T-1 · (3/4) or 5mm package. Encapsulating electronic devices in such packages is well known in the optoelectronics manufacturing industry.

The lens shown by 578 as a whole is preferably used to focus the light on the exposure transducer 178. The lens 578 can be provided by a separate and independent lens located between the sensing circuit 15 and the ray 570 source, or may be integrated with the encapsulant 172 as shown in FIGS. 40-46. In either case, the lens 578 defines the field of view of the sensing circuit 15 and provides improved sensitivity via optical gain. The lens can define the field of view of the sensor so that it has a narrow or wide angle.

Next, referring to FIG. 47, a graph showing the field of view of the optical sensor is shown as a function of the distance of the photodetector from the lens. The field of view of the exposure transducer 178 in the sensing circuit 15 is defined as the viewing angle θ formed by the ambient rays 570 with respect to the optical axis 580 passing through the exposure transducer 178. The half-width field of view of the spherical lens 578 is expressed by Equation 1. θ = 90-arccos {r / R} + n₂/ n₁* sin {arcos {r / R} -arctan {(d- (R- (R-)²-r²)^1/2)) / r}} Where r is the aperture radius of the lens, R is the radius of curvature of the lens 578, n₂Is the index of refraction of the material in the housing 172, n₁Is the refractive index outside the housing 172, d is the distance from the center of the lens 578 to the exposure transducer 178, and θ is measured in degrees. Normally, the T-1 (3/4) housing 172 is filled with epoxy, and the sensor circuit 15 is n.₁To n₂Operates in air with a ratio of approximately 1.5. Curve 590 plots a half-width field of view θ as a function of the distance d of the T-1 · (3/4) housing with a spherical lens 578 with radius R of 5.0 mm. The field of view diminishes as the light transducer 178 moves farther from the lens 578.

Next, referring to FIG. 48, a graph showing the optical gain of the optical sensor as a function of the distance of the photodetector from the lens is shown. Assuming a paraxial approximation of the ray 570, the optical gain of the lens 578 is that of the additional light energy collected by the light converter 178 with the lens 578 and the light energy collected by the light converter 178 without the lens 578. It can be estimated by considering the ratio. This can be calculated by considering a cone of light with a bottom surface on the surface of the lens 578 and a tip at the focal point of the lens 578. As a result, the optical gain G can be expressed as a function of the ratio of the cross section of the cone to the area of the optical converter 178, which is in the form of Equation 2. G = f²/ (fd)²

Curve 600 shows the optical gain G as a function of the distance d of the T-1 · (3/4) housing with a spherical lens 578 with a radius R of 5.0 mm and a focal length f of 15.0 mm. As the light transducer 178 moves away from the lens 578, the optical gain increases.

For use in auto-dimming rear view mirrors, the distance d between the lens 578 and the photodetector 178 should be adjusted to optimal performance for use as a front facing ambient light sensor and a rear facing glare sensor 62. Can be done. As further described below, the anterior ambient light sensor should have a wide field of view, but not as sensitive as the glare sensor. The glare sensor should have a narrower field of view, but must be more sensitive and therefore benefit from higher optical gain. In the above lenses, a distance d between 2 mm and 3 mm is suitable for the front ambient light sensor 58, and a distance d between 6 mm and 7 mm is suitable for the glare sensor. In addition to modifying lens parameters, other lens types such as aspherical, cylindrical, and similar are also available within the spirit and scope of the present invention.

Next, referring to FIG. 49, a graph showing the frequency response of the human eye is shown. Curve 610 represents the relative photopic vision or daylight frequency response of the human eye. Curve 612 represents the relative scotopic vision or nocturnal frequency response of the human eye. In addition to being more sensitive to luminosity, the scotopic response 612 is shifted more ultraviolet than the photopic response 610.

Next, referring to FIG. 50, a graph showing the frequency response of a typical optical transducer is shown. The relative frequency response of a typical photoderode optical transducer 178 is shown as curve 620. Compared to the photopic response curve 610 or the scotopic response curve 612, the frequency response of the exposure transducer 178 contains a fairly high infrared sensitivity. Depending on the application, a filter may be placed in front of or built into the sensor device to make the output of the exposure transducer 178 more similar to the desired frequency response. The type of filtering required for the optical sensor device will be determined by the application in which the sensor is used.

Next, with reference to FIG. 51, an optical sensor package 1950 in which the housing incorporates a filter is shown. The window 174 of the housing 172 includes a filter 630 that can operate to attenuate some components of the light beam 570 that hit the exposure transducer 178. For example, the filter 630 can be an infrared filter such as a hot mirror commercially available from Optical Coating Laboratories, Inc. in Santa Rosa, California. A lens (not shown) can be placed in front of the infrared filter 630 to control the image focused on the transducer. Other examples of the filter are described in US Pat. No. 4,799,768 granted to Gahan and US Pat. No. 5,036,437 granted to Macks.

It is envisioned that the filter 630 can be provided for sensor devices that use other configurations. For example, a separate filter (not shown) can be mounted in front of the optical sensor device in a common housing with the sensor device. For example, a thin glass bandpass filter such as a BG28 filter or a BG18 filter commercially available from Schott Glass Technologies, Inc. of Duryea, PA can be used. These filters reduce the infrared sensitivity of the sensing circuit 15. In yet another embodiment, the sensing circuit is by depositing a filter directly on a thin appliqué or semiconductor die 572 mounted on the surface of the sensor encapsulant using a material embedded in the housing 172 or an adhesive. Fifteen spectral characteristics can be modified.

The light-shielding transducer 216 described above with respect to FIG. 10 can be shielded over the entire optical spectrum with an opaque shield, or can be shielded over a portion of the optical spectrum using a filter. The shield or filter can also be incorporated into the sensor package. When using a filter, use a filter that separates the IR line from the visible line by blocking all IR lines that may otherwise be exposed to the shielding transducer, or by passing only the IR line. Can be desirable. If a filter that blocks IR lines is used, the output of the shielding transducer can be used as a more accurate measure of the light level at which the driver's eyes will react. If a filter that passes only IR lines is used, the output of the shading converter 216 can be subtracted from the other optical converters 178 to provide a more consistent output for the reaction characteristics of the human eye. The latter method is more cost effective because the filter that passes the IR line has a lower configuration cost than the filter that blocks the IR line.

Here, a method in which the interference filter can be directly deposited on the semiconductor sensing circuit 15 will be described with reference to FIGS. 52A to 52D. In the first step, the photoresist is deposited over the entire wafer. The photoresist may be any suitable commercially available photoresist material. The photoresist is then patterned so as to cover only the area of the surface of the wafer that needs to be protected from the deposition of optical coatings such as bonding pads, as shown in FIG. 52B. Next, an optical film coating 579 is applied to the surface of the die 572 as shown in FIG. 52C. The thin film 579 forms multiple layers and is deposited directly on the optical sensor. The first layer of the interference filter can be a silicon layer with a thickness of 50 to 80 nm, preferably 65 nm. The second layer of the interference filter is a layer of silicon dioxide with a thickness of 100 to 200 nm, preferably 145 nm. The third layer of the interference filter is a silicon layer with a thickness of 50-80 nm, preferably 60 nm. The fourth layer of the interference filter is a layer of silicon dioxide with a thickness of 100 to 200 nm, preferably 140 nm. The fifth layer of the interference filter is a thick layer of silicon dioxide for protection, which can be 200 to 500 nm thick. After depositing all five layers, the photoresist is lifted off using a conventional lift-off process, leaving the deposited film over the photosensitive area and no film over the bonding pad, as shown in FIG. 52D. The resulting die can be encapsulated to provide conventional packages such as the T1-3 / 4 packages of FIGS. 40-46. The interference filter described above filters light above 650 nm. Other materials can be applied in a similar manner to give other filter properties.

Next, with reference to FIG. 53, a graph of the frequency response of the window film that can be applied to the filter of the optical sensor is shown. A film with the desired frequency response, such as the XIR-70 provided by Southwall Technologies of Palo Alto, California, can be placed in the window of an optical sensor device. The spectrum of such a film is shown by curve 640. For example, apply an adhesive to the film, such as the 9500 PC provided by 3M Corporation, Minnesota. The adhesive film can then be attached to the surface of the sensing circuit 15. Referring here to FIG. 54, curve 650 shows the response of the sensing circuit 15 with the adhesive film having the frequency response shown in curve 640 of FIG. 53.

Having described the details of the sensor device and the various physical configurations for mounting the sensor in the rear view assembly, then the electrical system of the electrochromic mirror system using the sensor device will be further enhanced through some specific embodiments. This will be described in detail. First, with reference to FIG. 55, automatic dimming rear view mirrors 2024, 2026 using an optical sensor are shown. The dimming element represented by 2050 as a whole includes the variable transmittance element 2052 and the reflecting surface 2054. The dimming element 2050 is configured so that the reflective surface 2054 is visible through the variable transmittance element 2052. The dimming element 2050 exhibits a variable light reflectance in response to the dimming element control signal 2056. The front ambient light sensor 50a is generally positioned to receive the front ambient light 2032 from the front of the vehicle. The front ambient light sensor 50a generates a discrete ambient light signal 2060 indicating the amount of front ambient light 2023 incident on the front ambient light sensor 50a over a period of time during which the ambient light is integrated. Ambient light can be measured using the various periodic integration time periods shown in FIG. The glare sensor 50b is generally positioned to detect the glare 2034 from the rear of the vehicle and can optionally be arranged to see the glare 2034 through the variable transmittance element 2052. The glare sensor 50b produces a discrete glare signal 2064 indicating the amount of glare 2034 incident on the glare sensor 2062 over the glare integration time period. The control logic 66 receives the ambient light signal 2060 and obtains the ambient light level. The control logic 66 finds the glare integration time period based on the level of the forward ambient light 2032. The control logic 66 receives the glare signal 2064 and obtains the level of the glare 2034. The control logic 66 outputs the dimming element control signal 2056 and sets the reflectance of the dimming element 2050 so as to reduce the influence of the glare 2034 perceived by the vehicle driver.

One or preferably both of the glare sensor 50b and the anterior ambient light sensor 50a are mounted using a semiconductor light sensor with variable sensitivity. Such a sensor includes an optical converter that converts incident light into an electric charge as described herein. This charge produces a potential that has been collected over an integration time period, which is converted to a discrete digital output by sensors 50a, 50b, which output is analog-digital before being digitally processed in control logic 66. No conversion required. Eliminating ADC conversion reduces the cost of the microprocessor. As can be seen from FIG. 11, there is a delay in the optical-pulse converter. This delay is the time difference between the sample time period and the start of the measurement time period 420. This delay can be avoided by using the analog circuit of Figure 12A. However, the use of analog circuits results in an increase in two respects. First, the first wire is used for the input signal during the integration time period, and the second wire is used as the analog output signal from the differential amplifier 321 so that the number of wires on bus 164 is doubled. There is a possibility of becoming. Second, the control logic requires an ADC to convert this analog signal into a digital signal that can be used in the digital control logic. As mentioned above, one problem with silicon-based sensors, whether digital or analog signals are generated, is the difference in spectral sensitivity between silicon and the human eye. Therefore, the optical filter 2068 can be placed in front of or incorporated within the ambient light sensor 50a. Similarly, the glare filter 2070 can be placed in front of or built into the glare sensor 50b.

Filters 2068, 2070 attenuate some parts of the spectrum that can contain visible, infrared, and ultraviolet light, and the light that hits the sensors 50a, 50b, coupled with the frequency response of the optical converter in the sensors 50a, 50b, It is closer to the reaction of the human eye and corrects the coloring of vehicle windows such as the windshield. For auto-dimming rearview mirrors, an important goal is to reduce glare on the vehicle driver in low light conditions. In detail, in order to protect the scotopic vision that rapidly declines when exposed to bright light within the range of the scotopic curve 612, the exposure converters 50a, 50b are otherwise the vehicle driver's scotopic vision. It is necessary to have a frequency response similar to that of the scotopic curve 612 so that the mirror attenuates the light that would adversely affect the. If this filter is not used, the exposure transducers 50a, 50b need to at least attenuate the infrared response. This is becoming more and more important as high-intensity discharge (HID) headlamps, which emit more bluish light than incandescent and halogen lamps, become more widespread. Therefore, the filters 2068 and 2070 preferably provide the same filter characteristics as the scotopic curve 612.

As mentioned above, the variable transmittance element 2052 can be implemented using various devices. Dimming can be achieved mechanically using a liquid crystal cell, a suspended particle device, or preferably using an electrochromic cell that changes the transmittance depending on the applied control voltage. As will be appreciated by those skilled in the art, the present invention is independent of the type or configuration of the dimming element 2050. When the dimming element 2050 includes an electrochromic element as the variable transmittance element 2052, the reflective surface 2054 can be incorporated inside or outside the variable transmittance element 2052. Alternatively, the variable transmittance element 2052 can be a display having variable brightness.

Each of the internal rear view mirror 2024 and the external rear view mirror 2026 must include a dimming element 2050 for automatic dimming. Preferably, the internal rear view mirror 2024 also includes control logic 66, optical sensors 50a, 50b, and filters 2068 and 2070 if used.

Next, with reference to FIG. 56, a block diagram of a rear view mirror system with internal and external rear view mirrors according to an embodiment of the present invention is shown. The dimming element 2050 of the internal rear view mirror 2024 operates as described above. Each external rear view mirror 2026 includes an external dimming element 2080 with an external variable transmittance element 2082 that can operate to attenuate light from the rear view both before and after it is reflected from the external reflecting surface 2084. The external dimming element 2080 provides variable reflectance based on the external dimming element control signal 2086. The external dimming element 2080 can operate in any manner described with respect to the dimming element 2050, preferably an electrochromic mirror. The external mirror control unit 2088 generates an external dimming element control signal 2086. The external mirror control unit 2088 can be a part of the external rear view mirror 2026 or the internal rear view mirror 2024, or can be positioned outside the mirrors 2024 and 2026. Various embodiments that control the external dimming element 2080 depend on the amount of sensing and control contained within the external rear view mirror 2026.

In one embodiment, the control logic 66 of the internal rear view mirror 2024 determines the external dimming element control signal 2086 based on the outputs from the front ambient light sensor 50a and the glare sensor 50b. The external dimming element control signal 2086 can be generated directly by the control logic 66 or is based on the reflectance level calculated by the control logic 66 and transmitted to the external mirror control unit 2088 via the inter-mirror signal 2090. The external mirror control unit 2088 can generate the external dimming element control signal 2086.

In another embodiment, the external rear view mirror 2026 comprises an external glare sensor 50'positioned to receive glare 2034 from the rear view, which is of glare 2034 incident on the glare sensor 50' for a period of glare integration time. It can operate to output an external glare signal 2094 based on the quantity. The control logic 66 uses the external glare signal 2094 and the ambient light signal 2060 to determine the reflectance level of the external dimming element 2080. Similarly, in this case, the external dimming element control signal 2086 can be directly generated by the control logic 66, or can be generated by the external mirror control unit 2088 based on the reflectance level included in the inter-mirror signal 2090. it can. The external glare filter 2096, like the glare filter 2070, can be placed in front of the external glare sensor 50b'or built into the external glare sensor 2092 to give the external glare sensor 50b' a response close to that of the human eye. The inter-mirror signal 2090 and the external glare signal 2094 can be in the form of pulse width modulated signals, pulse density signals, serial data streams, or digitized and communicated via an automotive bus such as a CAN bus.

In yet another embodiment, the external glare sensor 50b'generates an external glare signal 2098 that is sent directly to the external mirror control unit 2088. The external mirror control unit 2088 is based on the external glare signal 2098 and the level of the front ambient light 2032 measured by the control logic 66 and sent to the external mirror control unit 2088 via the inter-mirror signal 2090. Determine the control signal 2086.

In yet another embodiment, the external rear-view mirror 2026 determines the reflectance of the external dimming element 2080, independent of the glare 2034 or front ambient light 2032 sensed by the internal rear-view mirror 2024. In this embodiment, the external rear view mirror 2026 operates relative to the internal rear view mirror 2024 as described above.

Next, with reference to FIG. 57, a schematic diagram showing an embodiment of the control logic of the automatic dimming internal rear view mirror is shown. This circuit represents an efficient and even cheaper implementation of the automatic dimming internal rear view mirror 2024. Similar logic can be used to implement automatic dimming external mirror control, headlamp control, moisture detection and moisture removal control, power window control, heating and cooling control, and the like. Control Logic 66 is a Microchip from Chandler, Arizona. Utilize a small, low-cost microcontroller represented by U1 such as PIC16C620A provided by Technology. The forward ambient light sensor 50a communicates with the microcontroller U1 via the interconnect signal 186 connected to the microcontroller input RB0. Similarly, the glare sensor 50b communicates with the microcontroller U1 via a separate interconnect signal 186a connected to the microcontroller input RB2. As described above, each interconnect signal 186 transmits an integrated time period 158 from the microcontroller U1 to the optical sensors 50a and 50b, and a light intensity time period 240 from the optical sensors 50a and 50b to the microcontroller U1. V_DDThe resistor R29 and the capacitor C4 connected between the ground and the ground supply the filtered power supply for the optical sensors 50a and 50b.

Parallel resistor R15 and diode D5, V_DDIs connected to node 708. Capacitor C12 is connected between node 708 and ground. Resistor R6 connects the common node 708 to the input / MCLR of microcontroller U1. The components D5, R15, R6, and C12 together form the power-on reset circuit indicated by 710. Power is supplied to the control logic 66 through the ignition line 712. The diode D1 protects against reverse polarity on the ignition line 712, and the diode D2 clamps the voltage generated by the ignition line 712 to approximately 5 volts. The capacitors C2, C7, and C11, the resistor R3, and the ferrite element E1 together form the power supply adjustment circuit shown by 714. Capacitor C10 and resistors R8, R9, and R27 together form the reverse signal conditioning circuit shown in 718. The reverse signal adjustment circuit 718 applies a low-pass filter to the reverse filter 716 to provide electrostatic discharge protection to the digital input pin RB6 on the microcontroller U1. The microcontroller U1 uses the signal on the reverse line 716 to clear the variable transmission element 2052 whenever the vehicle is in reverse. Microcontroller U1 has OSC1 pin and V_DDThe clock is controlled by the RC oscillator formed by the resistor R2 connected between the OSC1 and the capacitor C1 connected between the OSC1 pin and ground. V_DDThe resistors R30 and LED D3 connected in series between the and the open drain output RA4 of the microcontroller U1 can be mounted on the internal rear view mirror 2024 to alert the driver of the vehicle of the operating status of the control logic 66. Form an indicator lamp. The switches S1 and S2 are connected to the digital inputs RB1 and RB3 of the microcontroller U1, respectively, to allow selection of control options.

Next, with reference to FIG. 58, a schematic diagram showing the operation of the electrochromic dimming device control is shown. Part of the control logic 66 has been redrawn to better understand the control of the electrochromic variable transmittance element 2052. The electrochromic variable transmittance element 2052 may be implemented using any suitable variable reflectance device, for example, "SINGLE-COMPARTMENT, SELF-ERASING, SOLUTION-PHASE ELECTROCHROMIC DEVICES," given to Byker. SOLUTIONS FOR USE THEREIN, Can include the electrochromic device described in US Pat. No. 4,902,108 entitled "AND USES THEREOF (single-compartment self-erasing liquid phase electrochromic device, solution used in the device, and method of use thereof)". .. The electrochromic variable transmittance element 2052 darkens in response to the control voltage applied to the input node 720. When the applied control voltage is removed, the electrochromic variable transmittance element 2052 self-discharges, increasing the amount of light passing through. The electrochromic variable transmittance element 2052 can be cleared rapidly by shorting the input node 720 to ground.

The resistor R17 connects the input node 720 at node 722 with the emitter of Darlington pair Q10. The collector of Q10 is connected to the power supply through the current limiting resistor R5, which can have an impedance of, for example, 27Ω. The base of the Darlington pair Q10 is connected to the digital output RB4 of the microcontroller U1 through resistors R1 and R7. Also, the base of Q10 is connected to ground through resistor R4 and through resistor R7 and capacitor C16. Digital output pin RB4 is driven by pulse output 724 in response to pulse control 726 generated by software running on microcontroller U1. The pulse output 724 can generate a pulse signal such as a pulse width modulated signal. Preferably, the pulse output 724 acts as a switch, setting the output pin RB4 to either high voltage or low voltage during each transition time period as described below. Capacitors C16 and resistors R1, R4, and R7 together form the low-pass filter indicated by 728, smoothing the signal appearing on the digital output RB4. As a result of this smoothing, a substantially constant applied control voltage is generated at the input node 720 to obtain the desired fixed control level. Further, in Q10, the base-emitter diode voltage drop and the voltage divider formed between the resistors R4 and the sum of the resistors R1 and R7 set the operating voltage for the electrochromic variable transmittance element 2052. Typical values for components are 1 kΩ for R1 and R4, 100 Ω for R7, and 100 μF for C16. The input node 720 is approximately 1.2 volts with respect to the nominal current draw by the 5 volt digital output RB4 and the electrochromic variable transmission element 2052.

The performance of the control logic 66 can be improved by feeding back the control voltage applied to the electrochromic variable transmittance element 2052 received at the input node 720. The microcontroller U1 includes comparison logic that causes the pulse output 724 to supply a low voltage if the applied control voltage is greater than the desired control level and a high voltage otherwise. High voltage is usually V_DDClose to, low voltage close to ground. This comparison can be made by comparing a digital number representing the desired control level with a digitized applied control voltage obtained using an analog-to-digital converter (ADC). DAC730 and comparator 732 are used alternately. The DAC 730 produces the desired voltage level at the analog output AN2 depending on the desired control level for the DAC control 734 supplied by the software running on the microcontroller U1. The resistor R31 is connected between the analog output AN2 and the node 736, and the resistor R26 is connected between the node 736 and the ground. One input of the comparator 732 is connected to node 736 by analog input AN3. The other input of the comparator is connected to input node 720 with analog input AN0. The output of the comparator 732 indicates whether the desired voltage level is greater than the applied control voltage. The values of resistors R31 and R26 are chosen so that the voltage at node 736 is within the range of applied control voltage expected at input node 720 over the entire range of desired control voltage outputs from DAC730. Typical values for R31 and R2 are 390 kΩ and 200 kΩ, respectively.

Positive feedback is obtained by connecting resistor R24 between node 736 and node 722. The resistor R17 is used to detect the drive current through the electrochromic variable transmittance element 2052 and is therefore typically a low value such as 10Ω. The resistor R24 is typically a high value, such as 1.3 MΩ. As the drive current through resistor R17 increases, the voltage across resistor R17 increases, pulling up the voltage at node 736. Such an increase in voltage on the positive input terminal of the comparator 732 has the regenerative effect of increasing the duty cycle from the pulse output 724. This regenerative effect provides a better system response at high temperatures where the electrochromic variable transmission element 2052 increases current draw as the maximum operating voltage increases. Positive feedback also offsets the effect of internal resistance within the electrochromic variable transmittance element 2052.

Next, referring to FIG. 59, a timing diagram showing the electrochromic element transmittance control is shown. During the automatic dimming operation, the software running on the microcontroller U1 starts at a transition point delimited by a fixed transition period 742 (one of which is indicated by 740). The desired control level 744 indicates the desired level of transmittance of the electrochromic variable transmittance element 2052. The desired control level 744 can be an analog value, or is preferably a digital number determined by the microcontroller U1. The desired control level 744 is compared with the applied control voltage 746 by the comparison logic. Comparator 732 receives the applied control voltage 746 and the desired control voltage appearing at node 736. The output 738 of the comparator produces a difference signal 748, which is asserted when the desired voltage level representing the desired control level 744 is greater than the applied control voltage 746. The output 738 of the comparator is used to generate the control signal 750 on the output RB4. If the desired control level 744 is greater than the applied control voltage 746, the digital output RB4 is switched to high. If the desired control level 744 is less than the applied control voltage 746, the digital output RB4 is switched to low. Preferably, the lowpass filter 728 filters the control signal 750 to generate an applied control voltage 764.

The duration of the transition period 742 is set to suppress flicker of the electrochromic element 2052, which may be noticed by the vehicle driver, for example. The transition period 742 can preferably be between 2 seconds and 2 microseconds. In the system described above, 5 ms may be used for the transition period 742.

Next, referring to FIG. 60, a graph showing the reflectance of the dimmer is shown as a function of the applied control voltage. Curve 754 plots the percent reflectance of the dimming element 2050, including the electrochromic variable transmittance element 2052, as a function of the applied control voltage 756. Curve 754 shows that the reflectance decreases from about 86% to about 8% as the applied control voltage increases from about 0.2 volts to about 0.9 volts. FIG. 60 also includes a curve 756 showing current draw as a function of the applied control voltage 756 for a typical electrochromic variable transmission element 2052.

Referring again to FIG. 57, an additional circuit configuration is provided to rapidly clear the variable transmittance electrochromic element 2050. Transistor Q11 is connected to the variable transmittance electrochromic element 2050 with the collector at node 720 and the emitter at ground. The base of transistor Q11 is connected to digital output RB7 through resistor R23. When the digital output RB7 is asserted, the transistor Q11 turns on and acts as a switch to rapidly discharge the electrochromic variable transmittance element 2052. The capacitor C6 is connected between the collector and the base of the transistor Q11 to reduce the electromagnetic interference noise generated when the transistor Q11 is switched. Transistor Q12 is connected between the base and ground of transistor Q10 and is controlled by the digital output RB7. Transistor Q11 turns on with transistor Q12 to turn off transistor Q10, thereby preventing the electrochromic variable transmittance element 2052 from attempting to darken and clear at the same time. The resistor R7 is located between the capacitor C16 and the collector of the transistor Q12 to limit the discharge current from the capacitor C16 through the transistor Q12.

Next, referring to FIG. 61, a flow diagram showing the operation of the control logic 66 for the rear view mirrors 2024 and 2026 is shown. As will be appreciated by those skilled in the art, the actions shown in FIG. 61 and other flow diagrams are not necessarily continuous actions. Further, these operations are preferably implemented by software running on the microcontroller U1, but can also be performed by software, hardware, or a combination of both. The present invention transcends any particular implementation and is shown in the form of continuous flow diagrams for simplification of description.

At block 760, the ambient light reading is acquired and the average ambient light is initialized. When the automatic dimming system is first started, it initializes the average ambient light level by making the first reading of the front ambient light 2032 using the front ambient light sensor 50a. The collection of ambient light readings and the average ambient light level are described below in relation to blocks 762 and 770, respectively.

In block 762, the ambient light is read and the logarithm of the reading value of the ambient light is obtained. Using the semiconductor forward ambient light sensor 50a for integrated charge collection produces an ambient light signal 2060 with good resolution over a wide range of ambient light levels 2032. As mentioned above, this is achieved by obtaining various readings of the forward ambient light 2032 using different integration time periods 242,248,254 (FIG. 7). In one embodiment, four separate integration time periods are used, for example 600 μs, 2.4 ms, 9.6 ms, and 38.4 ms. Each of these cumulative time periods is four times different from the adjacent time period. Therefore, for example, the integration time period of 2.4 ms makes the sensitivity of the front ambient light sensor 50a to the front ambient light 2032 four times as sensitive as the integration in the integration time period of 600 μs. Typically, the shortest integrated pulse 242 is first utilized by the forward ambient light sensor 50a to produce the short signal pulse 244. The width of the short signal pulse 244 is measured by control logic 66. A forward ambient light sensor 50a in complete darkness can also produce short signal pulses 244 with a width less than 100 μs, so short signal pulses 244 when accurately reflecting the level of forward ambient light 2032. Set a minimum threshold to receive. Generally, this threshold can be 300 μs. If the short signal pulse 244 does not exceed the threshold, then the next longest integration time period is used by the forward ambient light sensor 50a. If the longest integration time period does not produce a reasonably long signal pulse, the forward ambient light 2032 is at very low levels and the mirrors 2024, 2026 can operate with maximum sensitivity to glare 2034.

The use of the logarithm of the ambient light signal 2060 makes it possible to use an inexpensive microcontroller such as the U1 which has only an 8-bit internal register and can be free of multiplication instructions. Since the microcontroller is a binary device, a logarithm with a base of 2 requires fewer instructions than a logarithm with a base of 10 or a natural logarithm. Here, an algorithm for obtaining an 8-bit binary logarithm having the most significant 4 bits representing an integer part and the least significant 4 bits representing a fractional part will be described. The 8-bit ambient light signal 60 obtained from an appropriate integration time period is examined bit by bit starting from the most significant bit until the first binary number 1 is found. The bit position containing the first binary number 1 is the integer part of the logarithm. The four most significant bits following the bit portion containing the first binary 1 are the fractional parts of the logarithm. Increment this value by a factor of 16 to better approximate the logarithm. Here, an example of binary logarithmic approximation is provided. Suppose the ambient light signal 2060 was measured to be 44 (00101101 at base 2). The most significant asserted bit is bit 5, so the integer portion of the resulting value is binary 0101. The next four bits following bit 5 are 0110, the fractional part of the resulting value is 0110, and the total value is 0101.0110. After incrementing, this binary logarithmic approximation is 0101.0111.

Next, referring to FIG. 62, a graph is shown explaining the binary logarithmic approximation according to the above algorithm. We are plotting the binary logarithm for a value N from 1 to 255. Curve 790 shows the actual binary logarithm. Curve 792 shows the approximate binary logarithm.

The ambient light signal 2060 needs to be scaled to compensate for various possible integration time periods. This can be done by adding a scaling factor to the binary logarithm of the ambient light signal 2060. For example, when measuring the forward ambient light 2032 using the longest integration time (38.4 ms), add a scaling factor of 0. If you want to use the next longer integration time (9.6ms), add a scaling factor of 2. If you want to use the next longer integration time (2.4ms), add 4. Add 6 to use the shortest integration time (600 μs). Since the maximum value resulting from the binary logarithmic approximation is 8 (1000.0000), there is no overflow due to the addition of the scaling factor.

Referring again to FIG. 61, the logarithm of the ambient light level is compared to the daylight detection level at block 764. The daylight detection level is a calibration value stored in a microcontroller 66, read-only memory, electronically erasable read-only memory, or the like during manufacturing. The daylight detection level is to prevent dimming of the dimming element 2050 during a rapid transition from dark to light, such as when a vehicle exits a tunnel into daylight, or clears the dimming element more rapidly. Used for. When the logarithm of the forward ambient light 2032 exceeds the preset daylight detection level, the variable transmittance element 2052 is cleared and the light element 2050 is set to the maximum reflectance in the block 766. Then, in block 768, the processing is delayed. The time period between entering the standby loop and reading the ambient light after a sufficiently long time is equal to the delay of the constant ambient light loop. This time period can be, for example, 400 ms. Following the wait for block 768, another reading of forward ambient light 2032 is taken at block 762. If the logarithm of the forward ambient light 2032 does not exceed the daylight detection level, the average value is acquired in block 770.

In block 770, the average value of the logarithmic value of the ambient light level is calculated. By first averaging the readings converted to the logarithm of the front ambient light 2032, the effect of temporary bright light in front of the vehicle by significantly distorting the average readings of the other dark front ambient light 2032 is reduced. Will be done. The logarithmic moving average of the ambient light signal 2050 can be obtained from a digital low-pass filter as represented by Equation 3. y (n) = x (n) / 64 + 63 y (n-1) / 64 Where x (n) is the binary logarithm approximation of the ambient light signal 2060 obtained just before being accurately scaled for the integration time period, y (n-1) is the previous filter output, y (n). ) Is the current filter output. The use of average logarithm in analog optical signals is described in US Pat. No. 5,204,778 entitled "CONTROL SYSTEM FOR AUTOMOTIVE REARVIEW MIRRORS" given to Jon H. Bechtel. ..

At block 772, the logarithmic mean of the ambient light level is compared to the threshold. The daylight detection level can be a calibration value stored in a microcontroller 66, read-only memory, electronically erasable read-only memory, or the like during manufacturing. If the front ambient light 2032 is bright enough, the vehicle driver will not be blinded by any modest amount of glare 2034 and the mirrors 2024, 2026 can be set to maximum reflectance. Therefore, when the logarithmic mean of the ambient light signal 2060 is not smaller than the threshold value, the dimming element 2050 is cleared in the block 766, and the standby of the block 768 is executed. If the logarithmic mean of the ambient light signal 2050 is less than the threshold, glare processing is started in block 774. Typically, the threshold used for comparison in block 772 is less than the daylight detection level used for comparison in block 764.

In block 774, find the glare accumulation time period. The integration time period of the glare sensor 50b is determined based on the ambient light signal 2060. The glare integration time period is inversely proportional to the logarithmic mean logarithm of the ambient light signal 2060, as described in Equation 4. T_G(n) = antilog₂(K₁-y (n)) -K₂Where T_G(n) is the integration time period of the glare sensor 50b with respect to the filter output at the sample time n, K.₁Is a multiplication constant, K₂Is an addition constant. Constant K₁And K₂Is empirically required. If the logarithmic mean of the ambient light signal 2060 is below a certain level, the maximum glare sensitivity integration time period is used.

In block 776, set up a gray account. The glare account indicates the number of glare reads performed during ambient light readings. The product of the glare account and the glare loop delay must be equal to the time between obtaining ambient light readings. For example, the glare account can be 3 and the time between glare readings can be 133ms.

At block 778, read glare. The pulse width returned from the glare sensor 62 as the glare signal 2064 is measured during the glare integration time period obtained by block 774. Optionally, a predetermined and extremely short integration time period similar to the integration time period derived from the pulse 240 used for the forward light sensor before making the measurement using the glare integration time determined in step 774. The glare reading can be measured in advance using, and it is assumed that the integration time period can be as short as 30 to 40 μs. If this short pre-measurement of glare is greater than the threshold level, the glare sensor is determined to be susceptible to extremely high levels of light indicating that the rear sensor is saturated. The mirror can be sufficiently dimmed in response to this condition. If this pre-measurement does not exceed the threshold level, processing is continued with the time period of the glare signal determined in block 774.

In block 780, set the value of the dimming element. The glare signal 2064 is used to determine the desired control level 744 that sets the reflectance of the dimming element 2050. This can be done, for example, by looking up tables that associate lower reflectance with the time duration of longer glare signals. The exact relationship between the level of the glare 2034 and the setting of the variable transmittance element 2052 depends on factors including the structure of the mirrors 2024, 2026, the vehicle configuration, and the priority setting by the vehicle driver. As mentioned above, the variable transmittance element 2052 can be controlled using the desired control level 744. For example, a manually activated mechanism can be provided in the mirror to allow the user to adjust the relationship between the glare level and the transmittance of element 2052.

At block 782, check the gray account. If the gray account is zero, the next ambient light reading is performed at block 762. If the gray account is non-zero, decrement the gray account in block 784. It then enters a wait loop at block 786. The glare loop delay time period is set to read glare at regular, predetermined intervals.

Automatic control of electrochromic mirrors by using a cylindrical lens or biradial lens 1720 (FIGS. 40, 43, and 44) in the optical sensor device to mount a glare sensor 50b whose vertical axis is horizontally oriented. Brings significant benefits to. The lens radius r of this sensor (Fig. 44) can be, for example, 1.25 mm to generate a focal length f of 2.5 mm, the distance between the exposed surface of the photodetector and the tip of the encapsulant of the optical sensor. d can be 2.15 mm. The encapsulant of the glare sensor 50b can be permeable and there is no diffusing agent in it. Specifically, the glare sensor is positioned within the housing of the rear view mirror so that the vertical axis of the cylindrical lens is oriented horizontally to obtain a wide viewing angle in the horizontal direction.

Particularly advantageous is the off-axis light sensitivity distribution of the lens 1720 shown in FIG. In FIG. 63, the central axis coincides with the center of the transducer region 532. As can be seen from the figure, the cylindrical lens has high off-axis sensitivity along its vertical axis. This is better illustrated by the Cartesian coordinates of the sensitivity curve shown in FIG. The peak of off-axis sensitivity occurs at an angle of approximately 50 °. This property can be utilized to improve the detection of light from passing vehicles, which is especially important when the internal mirror controls the external mirror. Specifically, the headlights of passing vehicles are off-axis from the glare sensor located inside the internal rear-view mirror 2024, even though they illuminate the external rear-view mirror 2026. A conventional glare sensor located on the internal rear view mirror will detect the attenuated light from the passing vehicle and therefore the mirror's when the light from the passing vehicle no longer illuminates directly through the rear window. Reflectance increases. The improved glare sensor device is more sensitive to off-axis light and therefore more sensitive to light within viewing angle β. In this way, the reduced reflectance of the mirror 2026 is maintained until the headlights of the passing vehicle are invisible to the vehicle driver through the mirror 2026. The off-axis distribution of the optical sensor can be significantly reduced by adding a diffusing agent or diffusing injection to the encapsulant, which is done when mounting the ambient sensor 50a using a cylindrical lens. Those skilled in the art will understand the advantages.

Control the headlamps 1516 (Figure 24) separately and automatically dimming the mirrors 2024, 2026 to remove moisture from windows such as wipers 1545, air conditioning control 1530 (including defogger and defroster), and similar. In addition to the various means of removal, the benefits can be obtained by combining the optical sensors 50a-50f with the control logic 66 from various applications. For example, the control logic 66 can control the state of the headlamp 1516 based on the level of light detected by at least one ambient light sensor 50c. The control logic 66 can also control the dimming of at least one rear view mirror 2024, 2026 based on the level of light detected by the front ambient light sensor 50a and the glare light sensor 50b. The control logic 66 can also turn on the headlamps 1516 when the level of light detected by the front ambient light sensor 58 is below the threshold level. This is bright enough that the light from directly above is detected by the ambient light sensor 50c and turns off the headlamps 1516, but the front area of the vehicle is a relatively dim light in a tunnel or wide overpass. In such a situation, the headlamp 1516 will light up.

In another embodiment, the control logic 66 measures the amount of moisture in a cleared area of a vehicle window, such as a windshield or rear window, based on the output from at least one moisture sensor 50f. The control logic 66 controls the means for removing water based on the measured amount of water (collectively the windshield wiper 1545 and the defroster and defogger of the air conditioning control 1530). Further, the control logic 66 controls the dimming of the rear view mirrors 2024 and 2026 based on the amount of water and the light level detected by the front ambient light sensor 50a and the glare light sensor 50b. This allows the control logic 66 to mirror if the window through which the light received by the forward ambient light sensor 50a or glare light sensor 50b passes is covered with moisture such as frost, snow, fog, and the like. It is possible to prevent 2024 and 2026 from dimming. Similarly, for windows cleaned by the wiper 1545, read from the front ambient light sensor 50a or glare light sensor 50b during the time interval when one of the wipers 1545 passes in front of the light sensors 50a, 50b. It can be ignored.

In yet another embodiment where the control logic 66 measures the amount of moisture on the cleaning area of the vehicle window and controls the means of removing the moisture 1545, 1530, the control of the headlamp 1516 is the detected moisture as well as 1 It can be based on the level of light detected by one or more ambient light sensors 50c. Again, if the window through which the light received by the forward aerial light sensor 50c passes is covered with moisture, the control logic 66 can set the headlamp 1516 to a predetermined state. Also, for windows cleaned by the wiper 1545, reading from the upper ambient light sensor 50c or glare light sensor 50b can be ignored during the time interval when one of the wipers 1545 passes in front of the light sensor 50c.

The present invention facilitates the automatic dimming of headlamps 1545, mirrors 2024, 2026, and other or in addition to the various means of removing moisture from windows 1545, 1530, to control other equipment of the vehicle. Can be adapted. For example, power windows, sunroofs, moon roofs, convertible tops, and the like can be closed automatically when they detect moisture such as rain. Also, in addition to the headlamps 1516, various lights such as running lights, parking lights, paddle lights, courtesy lights, dashboard lights, and the like, ambient lighting conditions, moisture detection, vehicle running conditions, and the like. It can be automatically controlled based on one or more of the things. The state of the indoor heating and cooling system, including air conditioning, heaters, ventilation openings, windows, and similar, is one of ambient lighting, moisture detection, vehicle running, inside temperature, outside temperature, and similar. It can be controlled automatically based on one or more.

The control logic 66, which receives optical signals 164 from a plurality of optical sensors 50 and generates control signals for vehicle equipment, can be in one housing or distributed throughout the vehicle. The elements of control logic 66 can also be included within the optical sensor 50. The elements of control logic 66 can be interconnected via a variety of means, including individual wiring, buses, fiber optics, radio, infrared, and the like. The control logic 66 can include many collaborative processors, or single multitasking processors. The operation can be implemented with software , firmware, custom hardware, discrete logic, or any combination. The present invention is independent of the method or means of implementing control logic 66.

External fog of the type that requires the activation of front and / or rear fog lights can be automatically detected using a reflected light detection system that is substantially similar to that provided for moisture detectors. Is assumed. In order to detect such external fog, the light source and the sensor are arranged at a certain distance so that the light from the emitter detected by the sensor is reflected from a point several meters from the vehicle. In an environment where the detected reflected light level is substantially constant, greater than the threshold level, and continuously detected over a considerable period of time, the front and / or rear vehicle fog lights can be turned on automatically.

Therefore, it is understandable that an improved device control system has been disclosed. This system is easier to manufacture because it can compensate for fluctuations in the performance of the optical sensor with a microcontroller. Mirrors can be easily manufactured by automatic means. Further, since this system can utilize low-cost control logic, it can be provided at a lower cost. The system reliably detects light over a wide range of light while significantly reducing temperature dependence.

The above description is considered only for preferred embodiments. Those skilled in the art and those who manufacture or utilize the present invention will recall modified forms of the present invention. Accordingly, the embodiments shown in the drawings and described above are for illustration purposes only and limit the scope of the invention as defined in the appended claims to be construed in accordance with the principles of patent law, including the doctrine of equivalents. It is not something to do.

<figref num="1">It is a perspective view of the sensor device configured according to this invention.</figref><figref num="2">It is a side sectional view of the sensor device shown in FIG. 1, which first shows the tracking of various light rays passing through a diffuser.</figref><figref num="3">It is a top view of the lead frame used for constructing some sensor apparatus according to this invention.</figref><figref num="4A">It is a side view of the sensor device arranged near the aperture which arranges a lens.</figref><figref num="4B">It is a side view of the sensor device arranged far from the aperture which arranges a diffuser.</figref><figref num="4C">It is a side view of the sensor device according to the present invention arranged at a considerable distance from the aperture in which the diffuser is arranged.</figref><figref num="5">Blocks and schematics showing circuit configurations that enable processing and sensing circuits that can be used in the sensor device structures of the invention interconnected by a single line transmitting both sensitivity control and sensor output. It is an electric circuit diagram.</figref><figref num="6">It is a timing diagram which shows the operation of the circuit structure of FIG.</figref><figref num="7">It is a timing diagram which shows the integrated duration control and sensor output of an optical sensor.</figref><figref num="8">It is the schematic of the light-pulse circuit used for the sensing circuit shown in FIG.</figref><figref num="9">It is a timing diagram which shows the operation of the optical-pulse circuit of FIG.</figref><figref num="10">FIG. 5 is a schematic diagram of an optional optical-pulse circuit with noise correction used in the sensing circuit shown in FIG.</figref><figref num="11">It is a timing diagram which shows the operation of the optical-pulse circuit of FIG.</figref><figref num="12">It is the schematic which shows the implementation of the optical sensor of FIG. 14 which uses a photodiode as an optical converter.</figref><figref num="12A">It is a circuit diagram of the alternative circuit which converts the LIGHT signal and NOISE signal of FIG. 12 into an output signal.</figref><figref num="13">It is a block diagram which shows the embodiment of the packaging, output, and control of an optical sensor.</figref><figref num="14">It is a block diagram which shows the embodiment of the packaging, output, and control of an optical sensor.</figref><figref num="15">It is a block diagram which shows the embodiment of the packaging, output, and control of an optical sensor.</figref><figref num="16">It is a block diagram which shows the embodiment of the packaging, output, and control of an optical sensor.</figref><figref num="17">It is a block diagram which shows the sensor logic which internally determines the integration time period signal.</figref><figref num="18">FIG. 3 is a block diagram showing the use of optical transducers with different effective areas to achieve different sensitivities.</figref><figref num="19">FIG. 6 is a block diagram showing the use of optical transducers with different apertures to increase the dynamic range.</figref><figref num="20">It is a schematic diagram which shows the capacitance of different transducers for different light induction charge amounts to realize variable sensitivity.</figref><figref num="21">It is a graph of the output potential as a function of the accumulated incident light of the converter of FIG.</figref><figref num="22">It is the schematic which shows the photodiode converter which incorporated the anti-blooming gate.</figref><figref num="23A">It is an elevation view of the front surface of the rear view mirror assembly which incorporated the sensor device of this invention.</figref><figref num="23B">It is an elevation view of the back of the rear view mirror assembly which incorporated the sensor device of this invention.</figref><figref num="23C">It is the top view of the back of the rear view mirror assembly which incorporated the sensor device of this invention.</figref><figref num="23D">It is an elevation view of the side surface of the rear view mirror assembly which incorporated the sensor device of this invention.</figref><figref num="24">It is a block type electric circuit diagram which shows the vehicle equipment control system which uses the sensor device of this invention.</figref><figref num="25">It is a side view of the moisture detection system using the sensor device of this invention.</figref><figref num="26">It is an exploded perspective view of the rear view mirror assembly constructed according to this invention.</figref><figref num="27">It is another exploded perspective view of the rear view mirror assembly shown in FIG.</figref><figref num="28A">It is a perspective view of the surface facing the rear of the support / circuit board subassembly of the rear view mirror assembly shown in FIGS. 26 and 27.</figref><figref num="28B">FIG. 28 is a perspective view of the front-facing surface of the support / circuit board subassembly shown in FIG. 28A.</figref><figref num="28C">It is an elevation view of the front surface of the support / circuit board subassembly shown in FIGS. 28A and 28B.</figref><figref num="28D">It is an elevation view of the side surface of the support / circuit board subassembly shown in FIGS. 28A-28C.</figref><figref num="28E">It is an elevation view of the surface facing the rear of the support / circuit board subassembly shown in FIGS. 28A to 28D.</figref><figref num="29">It is an enlarged perspective view of the surface facing the rear of the secondary optical element mounted on the circuit board with respect to the glare sensor inside the rear view mirror assembly shown in FIGS. 26 to 28E.</figref><figref num="30">It is an enlarged perspective view of the glare sensor mounted on the circuit board with the secondary optical element removed shown in FIG. 29.</figref><figref num="31">FIG. 5 is an enlarged perspective view of the opposite side of the circuit board showing the mechanical connection of the glare sensor and the secondary optical element to the circuit board.</figref><figref num="32">It is a top view of the secondary optical element used for the assembly shown in FIGS. 26 to 31.</figref><figref num="33">It is a side view of the secondary optical element shown in FIG. 32.</figref><figref num="34">It is a side view of the secondary optical element shown in FIGS. 32 and 33 viewed from the side surface different from that shown in FIG. 33.</figref><figref num="35">It is the bottom view of the secondary optical element shown in FIGS. 32 to 34.</figref><figref num="36">It is a cross-sectional view of the secondary optical element seen along the line XXXVI-XXXVI of FIG.</figref><figref num="37">FIG. 6 is an enlarged partial view of the region of the secondary optical element identified by XXXVII in FIG.</figref><figref num="38">It is a cross-sectional view of the secondary optical element seen along the line XXXVI-XXXVI of FIG.</figref><figref num="39">It is an enlarged partial view of the region of the secondary optical element identified by XXXVII of FIG. 38.</figref><figref num="40">It is a perspective view of the sensor apparatus configured according to the 2nd Embodiment of this invention.</figref><figref num="41A">FIG. 5 shows tracking of light rays incident on an optical sensor based on light emitted from an on-axis light source and two off-axis light sources of +10 and -10 degrees.</figref><figref num="41B">FIG. 5 shows tracking of light rays incident on different photosensors with different lens radii, based on light emitted from an on-axis light source and two off-axis light sources of +10 and -10 degrees.</figref><figref num="42">It is a side view of the sensor device shown in FIG. 40 used in a particular implementation as a glare sensor in a rear view assembly.</figref><figref num="43">It is a perspective view of the sensor apparatus configured according to the 3rd Embodiment of this invention.</figref><figref num="44">It is an elevation view of the sensor device shown in FIG. 43.</figref><figref num="45">It is a perspective view of the sensor apparatus configured according to 4th Embodiment of this invention.</figref><figref num="46">It is a figure which shows the housing of an optical sensor.</figref><figref num="47">It is a figure which shows the field of view of an optical sensor as a function of the distance from a lens of an optical converter.</figref><figref num="48">It is a figure which shows the optical gain of an optical sensor as a function of the distance from a lens of an optical converter.</figref><figref num="49">It is a graph which shows the frequency response of a human eye.</figref><figref num="50">It is a graph which shows the frequency response of a typical optical converter.</figref><figref num="51">It is a figure of the housing which incorporated the infrared filter.</figref><figref num="52A">It is a side view of an optical sensor die in one step while depositing a film directly on a sensor transducer.</figref><figref num="52B">It is a side view of an optical sensor die in one step while depositing a film directly on a sensor transducer.</figref><figref num="52C">It is a side view of an optical sensor die in one step while depositing a film directly on a sensor transducer.</figref><figref num="52D">It is a side view of an optical sensor die in one step while depositing a film directly on a sensor transducer.</figref><figref num="53">It is a graph of the frequency response of a window film that can be used to mount an optical sensor filter.</figref><figref num="54">FIG. 5 is a graph of the frequency response of an optical sensor incorporating a window film having the frequency response shown in FIG. 53.</figref><figref num="55">It is a block diagram which shows the circuit structure of the automatic dimming rear view mirror.</figref><figref num="56">It is a block diagram which shows the rear view mirror system which includes an internal rear view mirror and an external rear view mirror.</figref><figref num="57">It is the schematic which shows one Embodiment of the control logic of the automatic dimming internal rear view mirror.</figref><figref num="58">It is the schematic which shows the operation of the electrochromic element transmittance control.</figref><figref num="59">It is a timing diagram which shows the electrochromic element transmittance control.</figref><figref num="60">It is a graph which shows the dimming reflectance as a function of the load cycle of a dimming control signal.</figref><figref num="61">It is a flow chart which shows the operation of the automatic dimming rear view mirror control logic.</figref><figref num="62">It is a graph which shows the binary logarithm approximation implemented in one embodiment of the control logic of an automatic dimming rear view mirror.</figref><figref num="63">It is an isoluminous plot of polar coordinates of an optical sensor according to FIGS. 43 and 44 with a cylindrical lens.</figref><figref num="64">It is an isoluminous plot of the orthogonal coordinates according to FIG. 63 viewed orthogonal to the vertical axis of the cylindrical lens.</figref>

Code description

20 lens structure 50 Sensor device 61 Refractive lens 112, 113 rays