Projection type picture display device and projection type picture display element

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a projection type image display device and a projection type image display device, and more particularly to a safety device thereof.

【0002】

[Conventional technology]

Projection-type image display (projector) using a liquid crystal element, DMD (Digital Mirror Device), etc. has been developed. To briefly explain the configuration of this projector with reference to drawings, as shown in FIG. 6, the light from the lamp 101, which is a light source, passes through the liquid crystal element 103 driven by the liquid crystal drive circuit 102, passes through the projection lens 104, and then screens. It is projected on 105. Reference numeral 106 denotes a power supply circuit for the lamp 101.

【0003】

In the past, it was common for this projector to project in a darkened room, but in recent years, there has been a demand for projection on a large screen in a bright room. Therefore, improvements such as a light source have been made in response to the above requirements, and at present, there are many projectors in which the intensity of the light projected from the projection lens is extremely strong. Therefore, if you inadvertently look into the projection lens 104 when you enter between the projection lens 104 and the screen 105 while using the projector, you may feel a great deal of glare and hurt your eyes. ..

【0004】

Therefore, in order to solve the above-mentioned problems, it has been proposed that when an object enters the area between the projection lens and the screen, it is detected by the object detection means and the projected image is immediately dimmed (for example). , Japanese Patent Application Laid-Open No. 2000-19637). However, there are problems that the configuration of the object detection means is complicated and it is difficult to accurately determine the range of the object detection from the relationship with the screen.

【0005】

[Problems to be Solved by the Invention]

The present invention has been made to solve the above-mentioned problems, and it is possible to accurately determine the range of object detection, thereby reliably detecting the case where an object enters the image projection area of the screen and the amount of projected light. It is an object of the present invention to provide a projection type image display device capable of controlling the above and a projection type image display device.

【0006】

[Means for solving problems]

The projection-type image display device according to claim 1 is a projection-type image display device including a projection-type image display that projects light from a projection lens and a screen that projects an image by the projection-type image display. A light projection means provided in the image display to project weak light to a portion outside the image display area of the screen, and a detection provided in a portion outside the image display area of the screen to detect light from the light projection means. It is characterized by comprising means and a control means for controlling the amount of light from the projection lens of the projection type image display when the light cannot be detected by the detection means.

【0007】

The projection type image display device according to claim 2 is the projection type image display device according to claim 1, wherein the projection type image display uses a liquid crystal element or a digital mirror device, and the light projection means. Is characterized in that it is composed of a member that attenuates and transmits light, which is arranged on the outer peripheral portion of the liquid crystal element or the digital mirror device.

【0008】

Further, the projection type image display device according to claim 3 is the projection type image display device according to claim 1, wherein a plurality of the detection means are provided in a portion outside the image display area of the screen, and the control means is the control means. It is characterized in that the amount of light from the projection lens is controlled when at least one of the detecting means cannot detect the light.

【0009】

The projection type image display device according to claim 4 is the projection type image display device according to claim 1, wherein the projection type image display uses a liquid crystal element, and the light projection means projects with the liquid crystal element. It is characterized in that it is composed of a light emitting element arranged at a position symmetrical with a liquid crystal element with respect to a half mirror arranged between the lens and the half mirror.

【0010】

The projection type image display according to claim 5 is a projection type image display that projects light from a projection lens, and projects weak light onto a portion outside the image display area of the screen on which the image by the projection type image display is projected. When the light projection means, the detection means for detecting the light from the light projection means provided in the portion outside the image display area of the screen, and the detection means cannot detect the light from the light projection means. It is characterized by being provided with a control means for controlling the amount of light from the projection lens.

【0011】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the projection type image display device and the projection type image display according to the present invention will be described in detail with reference to drawings.

【0012】

FIG. 1 is a diagram showing an embodiment of a projection type image display device and a projection type image display device according to the present invention. Reference numeral 1 denotes a screen on which an image is projected, and a plurality of light receiving elements 2 are arranged at equal intervals on the outer peripheral portion 1b of the image display area 1a of the screen 1. 3 is a projector which is a projection type image display. The internal configuration of this projector 3 is shown in FIG. 31 is a lamp that is a light source (for example, a high-pressure mercury lamp), 32 is a power source for a light source for the lamp 31, 33 is a liquid crystal element, and 34 is a liquid crystal drive circuit for the liquid crystal element 33. Further, 35 is a projection lens, and 36 is a control circuit that controls the power supply 32 based on the output from the light receiving element 2 arranged on the outer peripheral portion of the screen 1.

【0013】

FIG. 3 is a plan view showing the liquid crystal element 33 of FIG. 2 in detail, and shows a state in which a member 33c that attenuates and transmits light is arranged on the outer peripheral portion 33b of the image display area 33a. That is, the basic configuration of the projector 3 is the same as that of the conventional one, except that a member 33c that attenuates and transmits light is arranged on the outer peripheral portion 33b of the liquid crystal element 33.

【0014】

Next, the operation of the above device will be described. The normal projected light emitted from the projector 3 is projected onto the image display area 1a of the screen 1, and the weak light is projected onto the outer peripheral portion 1b of the image display area of the screen 1, and is projected onto the light receiving element 2 provided on the outer peripheral portion 1b. To reach.

【0015】

Here, if a human enters between the screen 1 and the projection lens 35, the light to the light receiving element 2 on the outer peripheral portion of the screen 1 is blocked, so that the light does not enter the light receiving element 2. When the control circuit 36 detects that even one of the light receiving elements 2 has not reached the light, the control circuit 36 controls the power supply circuit 32 to dimm the light of the lamp 31 or turn it off. In this case, as long as the light projected from the projection lens 35 has a safe intensity, the liquid crystal element 33 may be controlled to control the light intensity. When the light projected from the projection lens 35 is dimmed, the light that hits humans becomes weak light, so if the intensity of the weak light is attenuated to the extent that there is no problem even if the projection lens 35 is viewed directly. , It is safe even when looking directly at the projection lens 35.

【0016】

In the above embodiment, the distance between the light emitting elements 2 of the screen 1 is set to be sufficiently smaller than the size of a human head. Further, when a reflective element such as a DMD is used, the member arranged on the outer peripheral portion 33b of the liquid crystal element 33 for attenuating and transmitting light can be replaced with a portion having a low reflectance. Further, it is desirable that the attenuated light is invisible light such as infrared light because the invisible light does not interfere with the viewing of the image. In such a case, an infrared filter may be used as a portion for attenuating and transmitting light.

【0017】

According to the above-described embodiment, since the light receiving element 2 is provided on the outer peripheral portion 1b of the screen 1, it is possible to accurately and immediately detect that a human has entered between the projection lens 35 and the screen 1. This can reduce or block the amount of light from the lamp 31, which is the light source. Therefore, even when the projection lens 35 is inadvertently looked into the image display area of the screen 1, it is useful because it does not give extreme glare to the eyes.

【0018】

In the above embodiment, it is also possible to use a DMD (digital mirror device) instead of the liquid crystal element 33.

【0019】

4 and 5 are diagrams showing still another embodiment of the projection type image display device and the projection type image display according to the present invention. The same numbers are assigned to the parts similar to those in FIGS. 2 and 3, and the description thereof will be omitted.

【0020】

In this embodiment, the difference from the embodiment of FIG. 2 is that instead of providing the light receiving element around the liquid crystal element, the light emitting element 37 is arranged in a place different from the liquid crystal element 40 as shown in FIGS. It is a point that is set up. That is, the light emitting element 37 is attached to the substrate 42 placed at a position symmetrical to the liquid crystal element 40 with respect to the half mirror 41 arranged between the liquid crystal element 40 and the projection lens 35. The light emitting element 37 is arranged around the portion corresponding to the image display portion of the liquid crystal element 40. Therefore, the substrate 42 and the liquid crystal element 40 are optically at the same position when viewed from the projection lens 35, and the light emitted from the light emitting element 37 is projected onto the outer peripheral portion 1b of the screen 1.

【0021】

Since the light transmitted through the liquid crystal element 40 is polarized due to its nature, if only one polarized light is transmitted through the half mirror 41 and the other polarized light is reflected, such as a polarizing beam splitter, There is almost no attenuation of the light projected from the projection lens 35.

【0022】

As described above, according to this embodiment, the same effect as that of the previous embodiment can be obtained.

【0023】

By the way, in the above-mentioned two examples, a high-pressure mercury lamp is taken as an example as a light source, but it goes without saying that the present invention is not limited to this and can be applied. Further, in the embodiment, the weak light is projected onto the outer peripheral portion 1b of the screen 1 via the projection lens 35, but it is clear that the configuration may be such that the weak light is projected onto the outer peripheral portion 1b without passing through the projection lens 35. is there. Further, the control circuit 36 may be provided on either the screen 1 side or the projector 3 side.

【0024】

[Effect of the invention]

As described above, according to the present invention, there is provided a projection type image display device and a projection type image display device capable of reliably detecting when an object enters the image projection area of a screen and controlling the amount of projected light. Can be useful.

[Simple explanation of drawings]

[Figure 1]

The perspective view which shows one Example of the projection type image display device which becomes this invention.

[Figure 2]

The figure which shows the structure of the image display device of FIG.

[Fig. 3]

The plan view which shows the liquid crystal element of the image display of FIG. 2 in detail.

[Fig. 4]

The block diagram which shows the other embodiment of the projection type image display device which becomes this invention.

[Fig. 5]

The plan view which shows the arrangement of the light emitting element of the image display device of FIG.

[Fig. 6]

The block diagram which shows an example of the conventional projection type image display apparatus.

[Explanation of symbols]

1: Screen 1b: Screen outer circumference 2: Light receiving element 3: Projection type image display 31: Lamp 32: Power supply circuit for light source 33: Liquid crystal element 33c: Light attenuation and transmission member 34: LCD drive circuit 35: Projection lens 36: Power control circuit