Rain sensor with selectively reconfigurable fractal based sensors/capacitors

[0001] The present invention relates to a system for detecting the presence of rain and / or disturbance or the presence of other substances on a glass sheet (s) such as a windshield, rear window or sunroof of a vehicle. In some non-limiting examples of the invention, a plurality of sensor capacitors are held by a window such as a vehicle windshield, each capacitor having a different area. The sensor circuit sends an analog signal that is based on and / or relates to the capacitance of the sensor capacitors. In some embodiments, a switching circuit is provided to selectively switch between different sensing capacitors or different combinations thereof, to change the sensing area being analyzed and / or to change the sought feature. For example, in some embodiments, the switching circuit may selectively switch between: (a) a sensor (s) for detecting rain on the outer surface of the window, and (b) a sensor (s) for detecting one or more positions among: ice on the outer window surface, fog on the external surface of the window and / or moisture on the internal surface of the window.

BACKGROUND OF THE INVENTION AND SUMMARY OF EXAMPLES OF IMPLEMENTATION OF THE INVENTION [0002] The presence of moisture (e.g. rain or condensation) and / or other substances or residues on the front and / or rear windows of vehicles, if not removed immediately, may create dangerous driving conditions for drivers, passengers as well as pedestrians. Wiper blades are well known, which are a common way

53 / 59P29195EN00 removing such substances and reducing the risk of driving in hazardous conditions. Rain sensors have been developed to detect the presence of moisture (e.g. rain or other condensation) on the windshield of the vehicle and to turn on and off the wipers, if necessary, for automatic rain detection, and the like, and to take, for example, detecting the presence of snow moisture with rain, fog proper action of wiper blades at the appropriate speed - potentially reduces the amount of distractions to the driver, allowing him to focus his attention better on the road ahead. However, incorrectly activating / deactivating the wipers or not activating the wipers in the presence of moisture may also pose a risk to driving safety. In addition, these types of systems are also susceptible to interfering pollutants, which, if present on the glass, can cause false readings / wiping.

[0003] Some traditional rain sensors are based on an electro-optical principle of operation. In some such techniques, raindrops are detected only by measuring the change in total internal reflection of the light beam at the glass - air border. Other electro-optical techniques try to analyze the brightness of the "image" of the glass to detect rain droplets or fog on the glass. However, these types of optical techniques have limited detection ranges, are quite expensive, and can cause erroneous indications as a result of using optical imaging as the only detection method.

Document EP-A 1306276 presents the preamble of claim 1 and claim 11.

[0004] It should therefore be mentioned that there is a need in the art for a moisture sensor (e.g. rain) that will have effective operation and / or detection.

[0005] In certain example embodiments of this invention, a plurality of sensor capacitors are supported by a window such as a vehicle windshield, each capacitor having a different area. The sensor circuit provides an analog signal that is based on and / or relates to the capacitance of the sensor capacitors. In some embodiments, a switching circuit is provided to selectively switch between different sensing capacitors or different combinations (or even possibly antennas and / or bands) to change the sensing area being analyzed and / or changing the sought feature. For example, in some embodiments, the switching circuit may selectively switch between: (a) a sensor (s) for detecting rain on the outer surface of the window, and (b) a sensor (s) for detecting one or more positions among: ice on the outer window surface, fog on the external surface of the window and / or moisture on the internal surface of the window. Such embodiments may or may not be used in combination with any other embodiment (embodiments) of the present invention.

[0006] In some embodiments of the present invention, a rain sensor is provided comprising: a sensing circuit comprising a plurality of sensing capacitors supported by a vehicle window, one or more moisture-sensing sensing capacitors on the outer surface of the window and comprising first and second capacitor electrodes separated from each other which are substantially coplanar; and a switching circuit for selectively connecting multiple sensor capacitors to a rain sensor reading circuit.

[0007] In other embodiments of the present invention, an electronic device (e.g., rain sensor, antenna system or the like) is provided comprising: a circuit

A sensor surface, a sensor surface comprising a plurality of different fractal structures, and a switching circuit for selectively combining different fractal structures or a combination thereof with a reading circuit. Fractal structures can be capacitive sensors, antennas with different bandwidths, or the like in various example cases.

[0008] In some embodiments of the present invention, there is provided a rain sensor comprising: a sensing circuit comprising at least one condenser that is sensitive to moisture on the outer pane; an adder receiving, directly or indirectly, an analog output signal from the sensor system and determining the difference between the analog output signal from the sensor system and the feedback signal; a quantizer comprising a comparator positioned after the adder that sends a bit stream or level based at least on the received signal higher or lower than a predetermined threshold; a lowpass digital filter located downstream of the quantizer for lowpass bitstream filtering to send a filtered digital signal; and a correlation engine that performs correlation on the filtered digital signal to determine if rain is present on the outer surface of the glass. In certain example cases, it can be said that this system uses sigma-delta modulation in the analog-to-digital transformation of the signal.

embodiments of the present method is a method of determining whether moisture is present on the exterior surface of a vehicle window, the method comprising: receiving a signal relating to at least one sensing capacitor and processing the signal to obtain footprint characteristics and comparing the type characteristics with one or more of [0009] In the present invention, some signal is provided;

signal footprint 'advance set

The footprint characteristics of the signals stored in the memory in an external substance.

[0010] In the invention, to determine whether the detected substance on the vehicle surface is moisture, or other certain embodiments of the present invention, there is provided a rain sensor comprising: at least one sensing capacitor held by the window, the sensing capacitor being sensitive to rain, wherein a capacitor for making the outer pane surface; sensor has fractal geometry.

[0011] In certain examples of the invention, there is provided a rain sensor comprising: at least one sensing capacitor that is sensitive to moisture on the outer surface of the window; and a first sensing capacitor comprising first and second capacitor electrodes, each having a meandering shape, and wherein the first and second capacitor electrodes are substantially parallel to each other.

[0012] In certain example embodiments of this invention, there is provided a rain sensor comprising: a sensing circuit comprising at least a first and a second which are moisture sensitive to the windows; the sensing circuit includes at least one mimicking capacitor that mimics at least charging and / or discharging at least one of the first and second sensing capacitors; wherein the write pulse causes the charging of at least the first sensing capacitor, and the erase pulse substantially discharges each of the outer capacitors furthermore the sensing surface of the first mimicking surface;

sensing capacitor which the presence of the glass surface of the sensing capacitor area causes rain on the sensing fluctuation of the external voltage capacitor on the output electrode of the first imitating capacitor in

A method proportional to the voltage fluctuation at the output electrode of the first sensing capacitor, even if rain is not present in the imitation capacitor area; and wherein the rain is detected based on the output signal from the output electrode of the mimicking capacitor, wherein the output signal is read at least between the end of the write pulse and the start of the erase pulse.

[0013] In other embodiments of the present invention, a method for detecting rain on a surface of a window is provided, the method comprising: providing separate first and second recording pulses that cause the sensing capacitor of the circuit to charge the first sensing capacitor of the first and second sensing capacitors, in which it charges when the second sensing capacitor is substantially discharged, and the second sensing capacitor charges when the first sensing capacitor is substantially discharged, so the first and second sensing capacitors are charged at different times; each of the first and second sensing capacitors being sensitive to moisture on the surface of the window; providing a first erase pulse between the first and second write pulse periods, the first erase pulse substantially discharging the first sensing capacitor, and providing a second erase pulse after the second write pulse, the second erase pulse substantially discharging the second sensing capacitor; wherein the presence of rain on the glass surface affects the value of the output signal of the sensor circuit; and converting the analog output signal of the sensing circuit to a digital signal based on a digital signal determining whether rain is present on the surface of the glass.

[0014] In certain example embodiments of this invention, there is provided a rain sensor comprising: at least one sensing capacitor that is sensitive to moisture on the outer surface of the window, the sensing capacitor comprising a first capacitor electrode that receives the charging signal and a second a capacitor electrode separated from the first capacitor electrode; and in which the second capacitor electrode has an unsteady voltage, so the sensing capacitor is isolated from ground. It has been noticed that the transient voltage characteristics are beneficial in that they allow to reduce or prevent false readings resulting from electromagnetic interference or caused by external objects (e.g. human hand).

[0015] In certain example embodiments of this invention, a method is provided for detecting the presence of moisture (e.g. rain, dew, fog or the like) on the vehicle window, the method comprising: receiving data regarding at least two capacitors held by the window of the vehicle; autocorrelating data on each capacitor to obtain autocorrelation data; and determining, based on said autocorrelation data, whether moisture is present on the outer window of the vehicle. In some embodiments, data regarding at least two capacitors is received from an electrical circuitry that receives and / or reads capacity data from the at least two capacitors. In some embodiments, data regarding at least two capacitors is an output from an electrical circuitry that: (a) receives and / or reads data and / or signals from at least two capacitors, and / or (b) includes a capacitor (capacitors) ) or other circuit element (s) that mimic or substantially mimic the charging and / or discharging of at least two capacitors. In some embodiments, autocorrelation can be used as an initial step in

To determine if water may be present on the glass. However, it is possible that other substances may also detect the presence of (e.g. dust or dirt) on the glass, because the correlation signatures of these substances may be different.

[0016] In certain example embodiments of this invention, a moisture sensor (e.g. a rain sensor) to detect the presence of moisture on the vehicle window, the moisture sensor comprising: one, two or more capacitors; means for autocorrelating three or more or to obtain data data from one, two, all autocorrelation capacitors; and means based on determining in said autocorrelation data whether moisture is present on the vehicle window.

[0017] In certain example embodiments of this invention, cross-correlating data of the at least two capacitors may be performed to correlate data from different capacitors to obtain cross-correlation data. Then, based on at least the cross-correlation data, the type and / or amount of moisture can be determined. Cross-correlation data can also or instead be used to determine if a substance detected by autocorrelation is a substance other than moisture, such as dust or dirt, and if so, the wipers are not activated. In certain embodiments, cross-correlation may be performed after autocorrelation has been performed when certain conditions are met. As an example, cross-correlation can be made to determine if the moisture on the glass is a small rain, heavy downpour, fog, snow with rain, snow or ice (type of moisture).

[0018] In certain example embodiments of this invention, the autocorrelation data from the capacitor (s) can be checked for negative values. When the data

If the autocorrelation contains a negative value (s), then the system or method may indicate that it is not raining and / or may not operate the windshield wipers.

[0019] Furthermore, in some embodiments of the present invention, the system or method may calculate whether the autocorrelation curve gradient associated with the autocorrelation data is greater than one or another predetermined value; and if not, then the system or method may indicate that it is not raining, lower the wipers if they have moved, and / or not operate the vehicle wipers.

[0020] In certain example embodiments of this invention, the system or method may determine whether the shape of the autocorrelation curve or signal footprint characteristics associated with the autocorrelation data is different from the predetermined autocorrelation curve or signal footprint characteristics associated with normalized undistorted autocorrelation data. If it is not different or substantially different, then it may be indicated that it is not raining, the wipers may be lowered if they have been moving, and / or the wipers may not be activated. Although footprint characteristics are based on autocorrelation data in some embodiments of the present invention, in some cases other types of footprint characteristics may be used instead.

[0021] In some embodiments of the present invention, the conditions checked in the autocorrelation function include (i) a gradient of the normalized autocorrelation function (e.g., when no disturbance occurs, the absolute value of the gradient is one and changes with the disturbance), (ii) the sign of the autocorrelation function ( for example. when the CB radio is on or when the human hand touches the windshield, the values ​​oscillate between positive and negative), and (iii) the shape of the autocorrelation function as a function of time delays can also be used as a signature or type characteristic

"Footprint" to distinguish rain from other disturbances, and said shape can also be used to distinguish different types of rain or water content. Thus, in certain example cases, cross-correlation of data from at least two capacitors is performed only when one, two or all of the following conditions are met: (a) the autocorrelation data does not have negative values; (b) the autocorrelation curve gradient associated with said autocorrelation data is greater than one; and (c) the shape of the autocorrelation curve associated with the autocorrelation data (e.g.

the signal's footprint) is different from the shape of the predetermined autocorrelation curve associated with the normalized undisturbed autocorrelation data (e.g., the predetermined footprint).

Alternatively, (c) can be replaced by (c ') the shape of the autocorrelation curve associated with the autocorrelation data (e.g.

signal footprint characteristics) corresponds or essentially corresponds to the shape of a predetermined autocorrelation curve (e.g. predetermined signal footprint) associated with a known moisture pattern. In some embodiments of the present invention, the level of symmetry of the cross-correlation curve associated with the cross-correlation data may be determined.

[0022] In certain example embodiments of this invention, it is possible to compare autocorrelation between different capacitors. In certain example embodiments of this invention, such a comparison can be used to notify the system of whether to initiate wiping if water is present on the windshield when the sensor system is turned on.

[0023] In some embodiments, the sensor capacitor array may comprise at least n sensor capacitors, wherein n may be two, four, ten, or may be any other suitable

53/59 P29195PL00 number. The matrix may be any type of matrix, such as a linear matrix, any of the matrices shown in the figures, or any other type of matrix. Autocorrelation of data from capacitors and / or associated with all or fewer sensor capacitors can be performed to obtain autocorrelation data.

[0024] In certain example embodiments of this invention, capacitors are formed based on a fractal pattern. For example and without limitation, one or more capacitors may be formed based on a fractal pattern, such as a Hilbert fractal pattern. Can be used including in the mentioned.

also other capacitive fractal patterns are a set of Cantor, but not limited to These fractal structures maximize or enlarge the periphery as a result provide high capacity The use of two-dimensional for a given sensor may not necessarily be

In addition, in iterations) the property of the physical surface of the invention.

surface areas. Fractal design also makes the sensor take up less physical space on the glass, while being electrically larger than its physical size.

The concentration of the transverse flux in fractal geometry allow the sensor to detect rain / water dispersed over some examples of its higher iteration (their higher fractal capacitor (s) are such that they form their own Faraday cage or Faraday cage). Also, in some embodiments , the rain sensor can be electrically connected to the vehicle's LIN (Local Interconnection Bus).

[0025] In certain example embodiments of this invention, a method of detecting the presence of moisture on a vehicle window, such as a windshield, rear window or sunroof, is provided, the method comprising: receiving data from at least two capacitors held by the window

Listed on the vehicle; correlating data from one or more capacitors to obtain correlated data; determining, based on at least correlated data, (a) whether moisture is the exterior surface of the vehicle window, and / or (b) the type and / or amount of the substance present on the exterior surface of the vehicle window. For example and without limitation, the correlation may be autocorrelation and / or cross-correlation.

[0026] In certain example embodiments of this invention, there is provided a method of operating a windshield wiper (s) in response to a detected rain, the method comprising reading data from a capacitive matrix having at least two capacitors;

performing autocorrelation of each capacitor data individually, determining autocorrelation data whether it rains data rain; performing capacitor correlation; determining the type and / or amount of rain from the cross-correlation data; operating the wipers if rain is detected; and, stopping or not starting the wipers if one or both of the determination steps indicate that it is not raining. In some embodiments, the symmetry level of the cross-correlation curve may be determined, and the wiper speed relative to the symmetry level may be selected. The wiper speed can be selected from a number of predetermined wiper speeds in certain example cases. In some embodiments, only a single wiper is initiated for the boundary conditions detected in one or both determination steps.

[0027] In certain example embodiments of this invention, there is provided a method of operating a vehicle's windshield wipers in response to a detected rain, the method comprising reading capacitive data having at least two mathematically comparing data from each of the matrix capacitors;

capacitor

Determining from capacitors individually (e.g., autocorrelation); determining from the mathematically compared data of an individual capacitor whether it is raining; mathematical comparison of data from different capacitors (e.g. performing cross-correlation); mathematically compared data of different types and / or amounts of rain; operating the wipers if rain is detected; and, stopping or not starting the wipers if one or both of the determination steps indicate that it is not raining.

[0028] In some embodiments, a Sigmadelta modulator or other suitable circuit or software may be used to perform analog-to-digital (A / C) conversion of data from the capacitive matrix.

in embodiments, the comparator software may perform at least a check of the autocorrelation data under values, calculating whether the autocorrelation data gradient is greater than one, and / or attempting to match or substantially match the shape of the autocorrelation data with the shape of the data stored in the database. In some cases, the correlating engine calculates cross-correlations when all the conditions tested by the comparator are met.

In addition, in some or another kind of one of the following: relative to the negative [0029] In certain embodiments of the present invention, there is provided a system or method for activating a vehicle's windshield wipers in response to a detected rain, the system (or method) comprising a capacitive matrix having at least two capacitors; circuitry that reads capacity data from a capacitive matrix; a correlating engine or correlator that autocorrelates data from an electrical circuit assembly to determine the presence of rain, and performs cross-correlation of data from an electrical circuit assembly to determine the type and / or amount of rain, if it is determined that there is rain; and a wiper motor that

53 / 59P29195EN00 is capable of receiving a signal to direct whether the wipers should move or stop. In some embodiments, the symmetry level of the cross-correlation curve is calculated, and the wiper motor can select a wiper speed related to the symmetry level.

[0030] In some embodiments, the rain sensor includes at least two sensing devices (e.g.

sensor capacitors or the like) which are affected by rain on the windscreen surface; an assembly of electrical circuits that provides an output signal relating to sensor devices; and at least one correlating engine that (a) autocorrelates information from said electrical circuit assembly to determine if rain is present, and / or (b) cross-correlates information from said electrical circuit assembly to determine how fast it should operate at least one vehicle wiper and / or amount of rain.

[0031] In some embodiments, a system or method of activating a windshield wiper (s) in response to a detected rain is provided and includes a capacitive matrix having at least two capacitors; circuitry that reads capacity data from a capacitive matrix; an algorithm that mathematically determines the presence of rain on the glass based on data from the electrical circuit assembly, and mathematically determines the type and / or amount of rain if it is determined that there is rain; and a wiper motor that is capable of receiving a signal (s) to guide whether the wiper (wipers) should move or stop.

BRIEF DESCRIPTION OF THE DRAWINGS [0032] These and other properties and advantages will become better and more clearly understood with reference to the attached

53 / 59P29195EN00 detailed description of the embodiments, together with the drawings in which:

[0033] Fig. 1 (a) is a block diagram of components of an exemplary rain sensor according to an embodiment of the present invention.

[0034] Fig. 1 (b) is a cross-sectional view of a rain sensor according to an embodiment of the present invention that can use the features of Fig. 1 (a) and / or one or more of Figs. 2-12.

[0035] Fig. 1 (c) is a cross-sectional view of a rain sensor according to another embodiment of the present invention that can use the properties of Fig. 1 (a) and / or one or more figures

2-12.

[0036] Fig. 1 (d) a transverse sensor of the embodiment of Fig. 1 (a) shows a cross-sectional view of a rain according to another example of the invention which can use and / or one or more figures

2-12.

[0037] Fig. 1 (e) transverse sensor of the embodiment of the present feature of fig. 1 (a) is a cross-sectional view of a rain according to another example of the invention which may use and / or one or more figures

2-12.

[0038] Fig. 1 (f) of the transverse sensor of the embodiment of Fig. 1 (a) shows a cross-sectional view of a rain according to another example of the invention which may use and / or one or more figures

2-12.

[0039] Fig. 2A shows an example of an optimized pattern for a quarter of a capacitive matrix based on Hilbert fractals, such capacitors may be present on the window in the form of a sensor matrix in one or more

53 / 59P29195EN00 by the number of embodiments in the figures, for example 1 (a) 1 (f) and 4 - 12.

[0040] Fig. 2B shows another example of an optimized pattern for a quarter of a capacitive matrix, such capacitors may be present on the glass as a sensor matrix with one or more embodiments in the figures, for example 1 (a) - 1 (f ) and 4-12. [0041] In fig. 3 there is an enlarged image of yet another quarter of the capacitive matrix, where such capacitors may be present on the glass in the form of a sensor matrix in one or more embodiments in the figures, for example 1 (a) - 1 (f) and 4 - 12.

[0042] Fig. 4 is an exemplary circuit diagram including an exemplary circuitry used for a clock clock write in the readout electronics, for use, for example, in one or more embodiments in the figures, for example 1 (a) - 1 ( f) and 5-12.

[0043] Fig. 5 is an exemplary circuit diagram including an exemplary electrical circuit assembly used for an erase clock pulse in readout electronics, for use in one or more embodiments in the figures, for example 1 (a) - 1 (f), 4 and 6 - 12.

[0044] Fig. 6 is an exemplary time diagram obtained from the reading circuitry of Fig. 4

- 5.

[0045] Fig. 7 is an exemplary flowchart or state diagram showing how autocorrelation and cross-correlation data can be used to control wipers, according to an embodiment of the present invention that can be used in conjunction with one or more Figures 1-6 and 8-12.

[0046] Fig. 8 is an exemplary flowchart showing how autocorrelation and cross-correlation data can be used to control wipers, according to an embodiment of the present invention that can be used in conjunction with one or more of Figures 1 7 and 9 - 12.

[0047] Fig. 9 is an exemplary stylized view illustrating how a raindrop may move on the windshield.

[0048] Fig. 10 is a graph illustrating exemplary experimentally obtained maximum values ​​of non-normalized autocorrelation for various disorders.

[0049] Fig. 11A is an example of an experimentally obtained autocorrelation snapshot indicative of heavy rain.

[0050] Fig. 11B is an example of an experimentally obtained autocorrelation snapshot indicative of a light fog.

[0051] Fig. 11C is an example of an experimentally obtained autocorrelation snapshot indicative of interference with CB radio.

[0052] Fig. 11D is an example of an experimentally obtained autocorrelation snapshot indicating a live grounded element.

[0053] Fig. 12A is an example correlation matrix indicating light rain.

[0054] Fig. 12B is an example correlation matrix indicating heavy rain.

[0055] Fig. 13 is an example of autocorrelation according to an embodiment of the invention.

[0056] Fig. 14 is a graph showing exemplary cross-correlation data derived from capacitors C1, C2, according to some embodiments of the present invention.

[0057] Fig. 15 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain), according to an example of the present invention, using some of the signals of Fig. 14.

[0058] Fig. 16 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0059] Fig. 17 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0060] Fig. 18 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0061] Fig. 19 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0062] Fig. 20 is a cross-correlation chart illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0063] Fig. 21 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in

Time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0064] Fig. 22 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0065] Fig. 23 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0066] Fig. 24 is a cross-correlation graph illustrating cross-correlation values ​​as a function of time delays (time delays are expressed in microseconds in the time domain) according to an example of the present invention, using some of the signals of Fig. 14.

[0067] Fig. 25 is a block diagram illustrating an electrical circuit assembly and / or signal processing according to an embodiment of the present invention where a sensing capacitor (e.g. C1) is present, including sigma-delta modulation.

[0068] Fig. 26 is a block diagram illustrating an electrical circuit assembly and / or signal processing according to an embodiment of the present invention where multiple capacitors (e.g. C1-C4) are present, including sigma-delta modulation.

[0069] Fig. 27 is a block diagram illustrating sigma-delta modulation according to an embodiment of the present invention, wherein the processing is performed in an electrical circuit assembly, firmware and / or computer program.

[0070] Figs. 28 (a) and 28 (b) are block diagrams illustrating the advantages of using floating electrodes for

Sensor capacitors (e.g., C1-C4) in accordance with some embodiments of the present invention.

[0071] Fig. 29 is a block diagram illustrating sigma-delta modulation according to another embodiment of the present invention, wherein this processing is performed in an electrical circuit assembly, firmware and / or computer program.

[0072] Fig. 30 is a block diagram illustrating sigma-delta modulation according to yet another embodiment of the present invention, wherein this processing is performed in an electrical circuit assembly, firmware and / or computer program.

[0073] Fig. 31 shows a switching circuit that can be used in conjunction with any of the other examples of the use of the present invention to selectively switch between different sensing capacitors to change the sensing area analyzed and / or change the sought after feature.

DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION [0074] Referring now in greater detail to the accompanying drawings, in which the same reference signs indicate the same elements in several views.

[0075] In certain example embodiments of this invention, the system and / or method of operating a moisture sensor (e.g. rain) includes sensing based on capacitance that translates a physical input signal (for example, the presence of a drop of water on the windshield or the like) into a digital electric voltage signal that is received and interpreted by software (software) or a circuit (circuits), which decides whether the wipers should be activated and if so, at what speed. So capacitive coupling is used

53 / 59P29195EN00 is for detecting water and / or other substance on the outer surface of the windshield, e.g. a car windshield, sunroof and / or rear windshield. It should be noted that computational methods can be performed by computer hardware or a combination of computer hardware and software in various embodiments of the present invention. In certain example embodiments of this invention, no capacitance or reference capacitor is needed (i.e., no compensation capacitor is needed).

[0076] In certain example embodiments of this invention, a plurality of sensor capacitors are supported by a window such as a vehicle windshield, each capacitor having a different analog signal area, which is the capacitance of sensor capacitors, embodiments, a switching circuit is provided to selectively switch between different sensing capacitors or their various combinations (or even possibly antennas and / or bands), to change the sensing area being analyzed and / or to change the feature sought (e.g. see figures 4, 5, 26 and 31). For example, in some embodiments, the switching circuit may selectively switch between: (a) a sensor (s) for detecting rain on the outer surface of the window, and (b) a sensor (s) for detecting one or more positions among: ice on the outer window surface, fog on the external surface of the window and / or moisture on the internal surface of the window. Such embodiments may or may not be used in combination with any other embodiment (embodiments) of the present invention. [0077] Some embodiments of the present invention may use an electric permeability equation that gives a physical quantity that describes how an electric field affects a given medium and this medium affects the field

The sensor circuit provides based on and / or applicable to some

Electric. An example of a basic equation of electrical permeability is:

D = εοΕ + P, where D is an electric flux, ε0 is a vacuum dielectric constant, E is an electric field (for example, the voltage between plates or electrodes divided by distance or V / m), and P is polarization. P polarization can also be described mathematically as:

P = ε_Γε₀Ε, where it means relative electric permeability (for example, the dielectric constant of water, ice, dirt, anything else that may be on the outside of a window, such as a windshield). In general, a high ε · value will correspond to a high polarity. The permeability of glass is approximately 8, and the permeability of water about 85. By substitution and factorization, the equation of electric permittivity can be rewritten as:

whether

D = ε₀ (s_r 1) E.

In this form, it can be seen that D is the response to E stimulation.

[0078] Capacity C is given as C = Q / V, where Q is the load and V is the potential expressed in volts. In addition, C = Φ / ν, where Φ is the electric flux associated with the Q charge. From Gauss's law:

Where dA is the surface area of ​​the differential square on the closed surface S. By substitution it becomes clear that the capacity is related to the potential difference:

C = JDdA / V.

[0079] These equations form the basis of an exemplary technique for measuring the interaction of water on glass using a sensor with a capacitive matrix for sampling above a window (e.g., glass). In particular, data from a sensor containing at least one or two or more capacitors (e.g. C1, C2, C3 etc.) can be used to determine whether moisture is present on the outer surface of the window, e.g. the windshield or rear window of the vehicle (e.g. example rain or the like). The above equations show that the presence of water on the window surface can affect the capacity of a properly located sensor capacitor.

[0080] Fig. 1 (a) is a block diagram of exemplary moisture sensor (e.g., rain) components in accordance with one embodiment of the present invention. Power supply 10 is connected to the electronic reading system 12, which may include one or more hardware, firmware and / or software. As will be described in more detail below, the sensor includes one or more capacitors forming a capacitive sensor in some embodiments. Although different types of capacitors may be used, each of the capacitors having a pair of approximately coplanar electrodes arranged in a fractal pattern can be used in the sensor in certain example embodiments of this invention. In some embodiments, the fractal pattern may be divided into a capacitive matrix. Data from and / or related to

The capacitor / sensor capacitors of the capacitive sensor 5 are received and read by the electronic reading system 12, which may consist of one or more hardware, firmware and / or software. The electronic reading circuit 12 collects electrical noise and converts it into digital signal / signals. This digital signal (s) is fed into the calculation module 14 (which may consist of one or more hardware, firmware and / or software) which determines the action that the wipers should take. For example, wipers can perform a single wipe, low-speed wiping, high-speed wiping and the like based on the data being analyzed from and / or associated with a capacitive sensor. The wipers can also be turned off, slow down / accelerate wiping movements and the like, based on the analyzed data originating and / or related to the capacitive sensor. The wiper control motor 16 receives instructions from the compute module 14 and instructs the wipers 18 to take appropriate action.

[0081] In some embodiments, the capacitive sensor 5 connects to the vehicle's LIN (Local Interconnect Bus). The LIN bus (not shown) is usually a serial bus to which slaves are connected to the vehicle. The LIN bus usually performs the reconciliation procedure (s) with the slave devices to ensure that they are connected and functioning, for example. In addition, the LIN bus can provide other information to slaves, such as the current time.

[0082] In some embodiments of the present invention, the capacitive sensor 5 comprises a plurality of capacitors in the form of a suitable matrix.

[0083] Fig. 1 (b) is a cross-sectional view of a vehicle window comprising a moisture sensor according to

Embodiment of the present invention. The vehicle windshield contains an inner glass substrate 1 and an outer glass substrate 2 that are laminated together via a polymer intermediate layer 3 of a material such as poly (vinyl butyral) (PVB) or others. An optional low-emission coating 4 may be present on the inner surface of the outer glass substrate 2 (or even on the surface of the substrate 1) in certain example embodiments of this invention. The low-emission coating 4 usually comprises at least one thin infrared reflecting layer of material such as silver, gold or the like, sandwiched between at least the first and second dielectric layers of material such as silicon nitride, tin oxide, zinc oxide or the like. Examples of low-emission coatings 4, for example and without limitation, are described in US Patent Nos. 6,686,050, 6,723,211, 6,782,718, 6,749,941, 6,730,352, 6,802,943, 4,782,216, 3,682,528, 6,936,347, the descriptions of which are incorporated herein by reference.

[0084] Fig. 1 (b) shows an example of a capacitive sensor capacitor. Although the capacitive sensor of Fig. 1 (a) typically contains many capacitors in the matrix, Fig. 1 (b) shows, for simplicity, only one capacitor. The remaining capacitors are similar in cross-section to the capacitor shown in Fig. 1 (b) in certain example embodiments of this invention. An example of the capacitor (C1, C2, C3, C4) of the capacitive sensor in Fig. 1 (b) comprises a pair of spaced apart coplanar electrodes 7 or substantially coplanar 8 and 8. The electrodes 7 and 8 are made of conductive material that can be printed or otherwise formed on the glass. For example, the capacitor electrodes 7 and 8 of the sensing capacitor can be made of or contain silver, ITO (indium zinc oxide) or other suitable

Conductive material. In some embodiments, the capacitor shown in Fig. 1 (b) is subjected to the action of a rain droplet on the outer surface of the glass, because the electric field ES of the capacitor extends to or outside the outer surface of the glass as shown in Fig. 1 (b) and can with a drop of rain or other material on the outside of the glass surface. The signals received from and / or associated with the sensing capacitor (sensing capacitors) and their analysis are described later in this document. [0085] In the embodiment of Fig. 1 (b), an opaque insulating layer 9 (e.g., black frit or enamel or other) present on the windshield above electrodes 7 and 8 is shown to cover the electrodes 7, 8 from the passenger (passengers). sitting inside the vehicle. It should be mentioned that the opaque layer 9 is only present on a small part of the glass, including the area where the capacitive matrix of the rain sensor capacitors is located. In some example cases, the capacitive matrix of the rain sensor and thus the opaque layer 9 may be located on the windshield of the vehicle in an area close to the rearview mirror mounting bracket. In some embodiments, the opaque layer 9 (e.g., from black frit or enamel) may be in direct contact with the fractal pattern of the capacitor electrodes 7, 8, since the layer 9 is not conductive. However, even if black frit layer 9 were conductive (which is possible), its dielectric constant is close to the value for water, so that it will not adversely interfere with the collection of data originating from and / or associated with C1 - C4 capacitors, as well as related analysis.

[0086] Fig. 2a is a top view illustrating an exemplary capacitive sensor matrix comprising four capacitors C1, C2, C3, C4. Each of these capacitors C1, C2, C3, C4 contains coplanar distant from each other

The first and second capacitor electrodes, 7 and 8, as shown in Fig. 1 (b) (or any of Figs. 1 (c) - 1 (f)). The capacitor electrodes 7 and 8 of each of the capacitors C1 - C4 may be made of conductive silver frit or similar material as shown in Fig. 2A. In addition, in some embodiments, a gap 22 of from about 0.2 to 1.5 mm, more preferably from about 0.3 to about 1.0 mm (e.g. 0.6 mm), between coplanar may be present

<td>with capacitor electrodes 7</td><td>and 8</td><td>capacitor</td><td>(C1,</td><td>C2,</td><td>C3</td>

<td>and / or C4), in accordance with</td><td>how</td><td>shown on</td><td>FIG.</td><td>2A.</td><td>IN</td>

<td>the embodiment in fig.</td><td>2A</td><td>capacitors</td><td>C1 -</td><td>C4</td><td>are</td>

covered with the insulating layer 9 of the black frit, which is the same as the opaque layer 9 discussed above with reference to Fig. 1 (b). In Fig. 2A, a contact field matrix is ​​present in the center of the sensor matrix that includes four contact fields electrically connected to the respective electrodes of 7 capacitors C1 - C4, as well as four contact fields electrically connected to the respective electrodes of 8 capacitors C1 - C4. An example contact field is indicated by reference number 28 in Fig. 2A. The four white contact fields 28 in Fig. 2A are electrically connected to the respective capacitor electrodes 7 of the C1 C4 capacitors, and the dark gray contact fields 28 in Fig. 2A are electrically connected to the respective capacitor electrodes 8 of the C1 - C4 capacitors. All C1 - C4 sensing capacitors are sensitive to moisture, e.g. rain, on the outer surface of the glass.

[0087] In the embodiment of Fig. 2A, each of the capacitors C1-C4 of the capacitive sensor is formed using fractal geometry. In particular, each of the coplanar electrodes 7 and 8 of each of the capacitors C1 - C4 is shaped in fractal geometry. Fractal patterns allow, for example, to realize high capacity in a small field

The surface and therefore are desirable to other geometries in some examples of rain sensor applications. Fractal geometry can be grouped into (a) random fractals, which may be called chaotic or Brown fractals, and contain a random noise component, and (b) deterministic or complete fractals. in the geometry of deterministic fractals, the self-similar structure results from the repetition of a structure or motif (or "generator") (i.e. self-similarity and structure at all scales). In deterministic or complete self-similarity, fractal capacitors can be formed by recursive or iterative means. In other words, fractals usually consist of or contain many copies of their own at various scales.

[0088] In the embodiment of Fig. 2A, it can be seen that the coplanar electrodes 7 and 8 of each capacitor (where electrodes 7 and 8 are shown but not labeled in Fig. 2A due to the black color of the frits 9, but are separated by slits 22) they have fractal geometries and are arranged substantially parallel to each other along the meander length of each capacitor. In other words, each electrode 7, 8 of a given capacitor (e.g., C1, C2, C3, C4) has a meandering shape in fractal geometry, but remains substantially parallel to the second electrode (the second of 7, 8) of the capacitor along the length of the capacitor's meander. The total length of each capacitor (e.g. C1) over the length of the fractal meander is from about 25 to 200 mm in some embodiments of the present invention, more preferably from about 30 to 90 mm, for example about 50 mm.

[0089] The fractal pattern of Fig. 2A is a Hilbert fractal pattern. The electrodes 7, 8 of the capacitors C1 - C4 in the embodiment of Fig. 2A form a Hilbert fractal pattern, by way of example only and without limitation. In particular, the capacitors shown in Fig. 2A are shaped in the form of third order Hilbert fractals. Hilbert fractals are

Continuous, space-filling fractals with a fractal dimension of two. This means that higher order fractals will be more square. The Hilbert fractal can be created by using the following L system:

Hilbert {

90 angle

Axiom X

X = -YF + XFX + FYY = + XF-YFY-FX +}

where "Angle 90" sets the following rotations to 90 degrees, X and Y are defined functions, "F" means "draw forward" "" + "means" rotate counterclockwise "and" - "means" turn clockwise. " Although in certain embodiments, Hilbert fractal geometries can be used to form C1-C4 capacitors, the present invention is not so limited, and other types of fractals can be used to form capacitor shapes. For example, the electrodes of 7.8 C1-C4 capacitors in any of the embodiments shown herein may be formed using any of the fractal structures depicted in any of US Patent Nos. 6,552,690, 6,104,349, 6,140,975, 6,127,977, 6,084,285, 6,975,277. of this description by reference. In certain example embodiments of this invention, as shown in Fig. 2A, 2B and 3, all sensor capacitors from the sensor matrix may have identical or substantially identical shapes.

[0090] In preferred embodiments, the capacitors C1

C4 in the sensor matrix can each be electrically floating (this may be called in some)

In such cases, the virtual mass), so as not to have a fixed common mass, for example, constant zero volts and / or spatially separated or similar, which may be useful in relation to the correlation function. In addition, the lack of common mass means that the capacitive matrix will not be subject to adverse effects from interference, for example electromagnetic interference, thereby reducing the potential for false wipes, false detection and the like.

[0091] The fractal structure of capacitors C1 - C4 can be used on any of the embodiments of Fig. 1 (a) 1 (f).

[0092] Fig. 1 (c) is a cross-sectional view of another embodiment of the present invention that can use the system of Fig. 1 (a) and one or more of the embodiments of Figs. 2-12. In the embodiment of Fig. 1 (c), the vehicle window (e.g. rear window) is made of only one glass sheet and the capacitor electrodes 7, 8 are formed directly or indirectly on the inner main surface of the glass sheet

Ten. The capacitor (e.g. capacitor C1) shown in Fig. 1 (c) is constructed so that it is affected by a droplet of rain (or other substance) on the outer surface of the glass, because the electric field ES of the capacitor extends into or out of the outer surface of the glass, such as shown in Fig. 1 (c) and can therefore interact with a droplet of rain or other substance present on the outer surface of the glass. Each of the C1 - C4 capacitors is formed in a similar manner. It should be noted that the use of the word "na" here means positioning both directly and indirectly on, and is not limited to mere physical contact or touching, unless explicitly stated. Opaque layer 9, similar to the layer shown in the embodiment of

Fig. 1 (b) may also be present in the embodiment of Fig. 1 (c) if desired.

[0093] Fig. 1 (d) is a cross-sectional view of another embodiment of the present invention that can use the system of Fig. 1 (a) and one or more of the embodiments of Figs. 2-12. In an embodiment in Fig. 1 (d) the vehicle window (e.g., laminated windshield) comprises glass sheets 1 and 2 laminated together via the polymer intermediate layer 3, and optionally includes a low-emission coating 4 either on substrate 1 or substrate 2. The embodiment of figure 1 (d) differs from the embodiment of figure 1 (b) in that the capacitor electrodes 7, 8 are present on the main surface of the glass substrate 1 which is furthest from the interior of the vehicle. In this embodiment, the capacitor electrodes 7, 8, in some cases, may contact the polymer intermediate layer 3. The capacitor (e.g., C1, C2, C3 or C4) shown in Fig. 1 (d) is designed such that a droplet of rain (or other substance) located on the outer surface of the glass pane affects it because the electric field ES of the capacitor extends to or outside the outer surface of the glass as shown in Fig. 1 (d) in therefore it may interact with a droplet of rain or other substance on the outer surface of the glass. Each of the sensor matrix C1 - C4 capacitors is formed in a manner similar to that shown for the capacitor of Fig. 1 (d). In the embodiment of Fig. 1 (d), an opaque layer 9 may also be provided, if desired, on a portion of the glass so as to cover the capacitor electrodes from the eyes of passengers. In the embodiment shown in Fig. 1 (d), the electrodes 7, 8 can be formed of a conductive silver frit or ITO printed or made directly onto and in contact with the surface of the substrate 1. However, the present invention is not limited to that only and the electrodes 7 and 8

Instead, one or more sensor capacitors may be formed and made of a metallic conductive infrared reflecting layer (e.g., a silver-based layer) of the low-emission coating 4 that is on the glass.

<td>on</td><td>FIG.</td><td>1 (e)</td>

<td>(B)</td><td>the</td><td>that</td>

<td>C2,</td><td>C3</td><td>C4)</td>

[0094] Fig. 1 (e) is a cross-sectional view of another embodiment of the present invention that can use the system of Fig. 1 (a) and one or more of the embodiments of Figs. 2-12. In the embodiment of FIG. 1 (e) the vehicle window (e.g., laminated windshield), comprises glass sheets 1 and 2 laminated together via the polymer intermediate layer 3, and optionally includes a low-emission coating 4 either on substrate 1 or substrate 2. The embodiments in Fig. 1 (e is different from the embodiment in Fig.

the electrodes 7, 8 of the capacitor (e.g. C1, C2, C3) are located on the main surface of the external glass substrate 2 that is closest to the interior of the vehicle.

Capacitor electrodes 7, 8 may contact the polymer intermediate layer 3 in this embodiment, in certain example cases. Capacitor (e.g. C1, C2,

C3, C4) shown in Fig. 1 (e) is designed so that a droplet of rain (or other substance) present on the outer surface of the glass acts on it because the electric field ES of the capacitor penetrates into or out of the outer surface of the glass as shown in Fig. 1 (e) hence it may interact with a droplet of rain or other substance on the outer surface of the glass. Each of the sensor matrix capacitors C1 - C4 is formed in a manner similar to that shown for the capacitor in Fig. 1 (e). May also be present in the embodiment in Fig. 1 (e), an opaque layer 9, if desired, on a portion of the windshield so as to cover the electrodes from the view of the passenger (s) of the vehicle.

[0095] Fig. 1 (f) is a cross-sectional view of another embodiment of the present invention that can use the system of Fig. 1 (a) and one or more of the embodiments of Figs. 2-12. the embodiment in fig. 1 (f) the vehicle windshield (e.g. laminated windshield) comprises glass sheets 1 and 2 laminated together via the polymer intermediate layer 3 and optionally includes a low-emission coating 4 on substrate 1 or substrate 2. The embodiment in Fig. 1 (f) differs from the embodiment in fig. 1 (b) in that the electrodes 7, 8 of the capacitor (e.g. C1, C2, C3, C4) are located on the main surface of the inner glass substrate 1, which is located closest to the interior of the vehicle, via a support element 12. The support element 12 is arranged between the glass substrate 1 and the electrodes 7, 8 can be made of glass, silicone or similar material. The capacitor (e.g. C1, C2, C3, C4) shown in Fig. 1 (e) is designed in such a way that it is affected by a droplet of rain (or other substance) on the outer surface of the glass, because the electric field ES of the capacitor extends to or outside the outer surface of the glass, as shown in Figure 1 (f) in connection with what can interact with this droplet of rain or other substance on the outer surface of the glass. Each of the sensor matrix C1 - C4 capacitors is formed similarly to the one shown for the capacitor of Fig. 1 (f). An opaque layer 9 may also be present, in the embodiment in Fig. 1 (f), if desired, on a portion of the glass so as to cover the electrodes 7, 8 from the eyes of the passengers of the vehicle.

[0096] Fig. 2B is a top view of an exemplary pattern of a quarter of a capacitive matrix of the fractal shape of capacitors C1-C4 for a capacitive sensor according to another embodiment of the present invention. The four capacitors shown in Fig. 2B are similar to

53 / 59P29195EN00 the capacitors of Fig. 2A, except for their precise shapes. The capacitors in Fig. 2B can be used in any of the embodiments in Figs. 1 (a) - (f). Superimposed dashed lines show capacitors C1 - C4. Divided into four distinct certain embodiments, the width of the outer line may be about 2 mm and the inner line about 1 mm.

[0097] Fig. 3 is an enlarged image of another example quadrant of a capacitive array of the fractal shape of capacitors C1-C4 for a capacitive sensor according to another embodiment of the present invention. The four capacitors shown in Fig. 3 are similar to the capacitors of Figs. 2A and 2B except for their precise shapes. The fractal capacitors of Fig. 3 can be used in any of the embodiments in Figs. 1 (a) - (f). The superimposed lines show an exemplary division between the capacitors C1 - C4 in Fig. 3. It should be noted that some embodiments may contain capacitive matrices with only two capacitors. However, in some embodiments it is preferred that they contain at least four capacitors to capture and determine the nuances of the disorder.

[0098] The use of fractal geometry for C1-C4 sensing capacitors may be beneficial in reducing false readings resulting from electromagnetic interference in certain example embodiments of this invention. In particular, high-iteration fractals help reduce the effect of this electromagnetic interference, because a high-iteration cage or quasi-Faraday fractal reduces the coupling of electromagnetic interference, thus reducing the adverse effects of electromagnetic interference. Fractals with a high number of iterations form quad Faraday cages.

[0099] In certain example embodiments of this invention, the readout electronics monitor the effects of rain and / or other disturbances on the windshield. In certain example embodiments of this invention, this process may be accomplished by sequential charging of capacitors, reading their condition, quantizing data, and / or deleting charges.

[0100] Fig. 4 is a schematic diagram of a sensor or readout circuit according to an embodiment of the present invention. The sensor circuit of Fig. 4 can be made of the electronic unit 12 and the capacitive sensor matrix 5 of Fig. 1. As capacitors C1 - C4 of the system of Fig. 4, any of the capacitors of Fig. 1 (b) - 1 ( f), 2A, 2B and / or 3. In certain example embodiments of this invention, the electrical circuit assembly of FIG. 4 it is used for the recording clock pulse in the reading electronics. Transistors Q1, Q2 and Q7 are panel-type MOSFETs, with transistors Q1 and Q2 mainly responsible for the write phase. Transistors Q5 and Q6 are n-channel MOSFETs.

[0101] Referring to Fig. 4, during the write phase of the transistor Q7, a write pulse ClkWr is applied, which transistor works as a resistor or switch, charging one or more capacitors C1 - C4 with sensor capacity Cs. Fig. 6 shows some of the signals used in the arrangement of Fig. 4 in the recording cycle. In the write cycle, the Q1 transistor works in saturation mode, because its gate and drain are shorted, thanks to which the Q1 transistor is turned on. In write mode, transistors Q4, Q5 and Q6 are off, while transistor Q2 is on. Transistors Q3 and Q4 are optional. When the transistor Q7 is turned on by the write pulse, we get a write cycle and Vcc appears on the capacitance Cs via the A line and charges one or more capacitors C1 - C4 of the sensor capacitance Cs. In some embodiments

The Vet voltage may be a DC voltage, for example, 5 V. At the same time, one or more C1 - C4 capacitors may be charged during the write cycle. However, in certain example embodiments of this invention, this system charges and reads the capacitors C1, C2, C3, C4 individually (see, for example, Figure 6). Accordingly, in some embodiments of the present invention, only one capacitor of the C1, C2, C3, C4 capacitors is charged in one write cycle.

[0102] The above process described for the left side of the sensor system of Fig. 4 is substantially reflected on the opposite or right side of the system of Fig. 4. As the current flows through the left branch, the current also flows through line B through the right branch and changes in capacity Cs are imitated or essentially imitated in the internal imitating capacity of Cint. When the transistor Q7 is turned on, the current also flows through the transistor Q2 (which is turned on) and charges the capacity Cint with the voltage Vcc. The charging of one of the C1 - C4 capacitors is therefore imitated by charging the Cint capacitor. In other words, the Cint capacitor is charged to the same degree or substantially the same as the capacitor (e.g. C1) charged on the other side of the system of Fig. 4. The output voltage of the system of Fig. 4, Vout (or Vo) depends on the capacity of Cint and is measured on or near the electrode of the Cint capacitor, as shown in Figure 4. An exemplary expression for Vout or Vo voltage is shown at the bottom of Figure 4. It should be noted that the output voltage Vout (or Vo) from the circuit of Figures 4-5 is associated and based on the capacitors C1 - C4 of the sensor Cs. In particular, the output Vout voltage of the system of Figs. 4-5 is related to and indicates the condition of the C1-C4 capacitors and the effect of the moisture present on the outer surface of the glass on these capacitors, although the voltage Vout is not measured directly on the C1-C4 capacitors. In particular, the voltage Vout (or Vo) is read in

During the write cycle as a result of the write pulse of Fig. 4 (see also Fig. 6). In the expression at the bottom of Figure 4 for the voltage Vout, W1 refers to Q1, W2 to Q2, L1 to Q1, L2 to Q2, where W is the transistor channel width and L is the transistor channel length. VT is the threshold voltage for each of the MOSFETs. It should be noted that in alternative embodiments of the present invention, the output voltage Vout of the system can be measured directly (instead of indirectly via Cint capacity) from the sensor capacitors C1 - C4.

[0103] Transistors Q3 and Q4 are optional. In certain example embodiments of this invention, these transistors may have low voltages (e.g., off) during the write phase, and may be on during the erase phase.

Fig. 5 sigma-delta that may digital-analog (DAC) [0104] In certain example embodiments of this invention, the output signal Vout (or Vo) of the sensor circuit of Fig. 4 (and is subjected to sigma-delta modulation. Modulators may be used in a sigma-delta converter, they can provide some degree of shaping or filtration of the quantization noise that may be present. Examples of sigma-delta modulators that can be used are described in US Patent Nos. 6,975,257, 6,972,704, 6,967,608 and 6,980,144, the content of which is incorporated herein by reference. In some embodiments of the sigma-delta conversion, oversampling, noise shaping, and / or decimation filtering may be performed. Examples of advantages of sigma-delta modulation include one or more of the following: (i) the requirements for an analogue anti-aliasing filter are complex so that they can be cheaper than some types of nyquist based systems; (ii) sampling and holding circuitry can be used due to high input sampling frequency and low precision

A / C conversion; (iii) due to the fact that the degree (s) of digital filtration may be behind the A / C conversion, the noise introduced during the conversion process, e.g. power ripple, reference voltage noise and the noise of the A / C converter itself, can be controlled ; (iv) since the sigma-delta transducer may be substantially linear, it may not be subject to significant non-linearity, and / or the level (levels) of background noise may be independent of the level of the input signal. Improved signal / noise (S / N) ratios can be realized.

[0105] Figures 4-5 show switches for selectively connecting different C1-C4 capacitors to the rest of the circuit. The circuit can read signals from all C1-C4 capacitors at the same time, or alternatively it can read signals only from one capacitor at a time, selected from among C1-C4 capacitors, or as an additional alternative, it can read signals from a combination of some, but not all C1-C4 capacitors at a given point in time. An example of a non-limiting switching circuit for selectively combining readout electronics with one or more C1-C4 capacitors depending on needs or requirements is discussed below with reference to Figure 31.

[0106] Fig. 25 is a simplified version of the sigma-delta modulator system, according to an embodiment of the present invention, intended to modulate and / or convert the output signal Vout (or Vo) of the circuit of Fig. 4 (and Fig. 5). In Fig. 25, the write pulse (see pulse at the bottom of Fig. 25) is used to charge the sensor capacitor (C1, C2, C3, C4) as discussed above with reference to Fig. 5. Rectangular excitation is used (e.g. for write and / or delete cycles) on the sensing capacitor to charge and discharge it. This process is reflected or emulated for Cint capacity as described. Output Vout (or Vo) signal

The system of Fig. 4 is subjected to sigma-delta modulation by a 60 sigma-delta modulator. In various embodiments of the present invention, Modulator 60 may be in the form of an electrical circuit assembly, firmware and / or software. Clock pulses 62 from the clock are introduced into the modulator 60 and trigger the latch of the modulator 60 quantizer. After performing sigma-delta modulation of the output Vout (or Vo) signal in modulator 60, the modulated signals 64 are fed to an optional digital filter 66 (e.g. low-pass filter or similar). Digital filter 66 processes the digital output signal 64 of the sigma-delta modulator, which is a stream of ones and zeros. These data are then scaled accordingly using the calibration factor (s). The filtered data 68 is then read via a serial interface 69 or similar and sent to a computer that performs correlation calculations for fragments of data packets. Data from interface 69 is then correlated (e.g., autocorrelated and / or cross-correlated) as explained here. Figure 26 is similar to Figure 25, except that in Figure 26 the matrix of sensor capacitors C1 - C4 is illustrated, which are multiplexed via a multiplexer. The multiplexer shown in Figure 26 can be used to selectively connect various C1-C4 capacitors to the rest of the circuit containing modulator 60. The circuit can read signals from all C1-C4 capacitors simultaneously through the multiplexer, or alternatively it can read signals from only one capacitor at a time, selected from among C1-C4 capacitors, or as an additional alternative, it can read signals from a combination of some, but not all, capacitors C1C4 at a given point in time. An example of a non-limiting switching circuit for use in the position of the multiplexer shown in Figure 26 for selective use

The connection of the readout electronics to one or more C1-C4 capacitors according to needs or requirements is discussed below with reference to Figure 31.

[0107] Fig. 27 is a block diagram illustrating an example of sigma-delta modulation that can be performed in the modulator 60 of Figs. 25-26. Again, in various embodiments of the present invention, this modulation can be performed in an electrical circuit assembly, firmware and / or software. The analog output signal Vout (or Vo) of the system of Fig. 4 (and Fig. 5) is received by the combiner 70 of the 60 sigma-delta modulator. The combiner 70 receives the analog Vout (or Vo) signal as well as the feedback signal from the feedback loop 71 of the modulator 60. The signal from the output of the combiner 70 is received by the integrator 72, whose output signal is in turn received by the quantizer 74, e.g. a quantizer single bit. Digital output 64 is then filtered 66, as explained above, and a little further. Sigma-delta modulation is advantageous in that it provides oversampling and allows the processing of noise, such as electromagnetic interference type and reduction of its adverse effects. In particular, the noise is distributed by sigma-delta modulation on the frequency band so that the signal / noise (S / N) ratio can be improved.

[0108] Fig. 29 is another example of sigma-delta modulation according to an example of the present invention. The sigma-delta modulator of Fig. 29 receives an analog input signal from the sensor circuit of Figs. 4, 5, which reaches the combiner 70. The combiner 70 determines the difference between the feedback signal and the input signal, and its output signal is transmitted to the integrator 72. The output signal from the integrator 72 is sent to the comparator 73. Comparator 73 decides whether its input signal is larger or smaller than a predetermined threshold value and based on it can send a signal

At least the input, single bit, bit stream, to the latch 75 (it should be noted that the quantizer 74 in Fig. 27 can include both a comparator 73 and a latch 75). The comparator output signal is received by a latch 75 for sampling. A way to reduce noise is to increase the clock cycle frequency from clock 62; for example. The sampling rate being twice the maximum frequency when increasing further is called the oversampling frequency. The digital bit stream sent from the latch is received by the digital low-pass filter 66. The low-pass filter is used because it is sometimes desirable to obtain an average signal level from the bit stream. The digital output signal may be a single-bit serial signal with a bit rate much higher than the data rate, and its average level may represent the average level of the input signal. The feedback loop, such as the loop in Fig. 27, includes an analog-to-digital converter 77 (DAC), which may be of the one-bit type or any other suitable type. The filtered data 68 is read via a serial interface 69 or the like and sent to a computer that performs correlation calculations for fragments of data packets. [0109] Fig. 30 is another example of sigma-delta modulation according to an embodiment of the present invention. The sigma-delta modulator of Fig. 30 receives the analog input signal of the sensor circuit of Figs. 4, 5, which reaches the first adder 70. The sigma-delta modulator diagram of Fig. thirty is the same as the diagram of Fig. 29 discussed above, except that in the modulator of the embodiment of Fig. 30 a second combiner 70 'and a second integrator 72' are provided.

[0110] Referring again to Fig. 4, in some embodiments of the present invention, each capacitor (C1, C2, C3, C4) is discharged before charging

53 / 59P29195EN00 next. The discharge process of each capacitor is described with reference to the reset pulse, with reference to Figs. 5-6.

[0111] Fig. 5 is a schematic diagram of the sensor circuit of Fig. 4 with respect to the erase cycle. During the erase cycle, the previously charged capacitor (C1, C2, C3 and / or C4) is discharged before the next write cycle. Figure 6 contains examples of signals used during the erase cycle (s). In some example cases, no read is performed during the erase phase. During the cycle or erase phase, the transistor Q7 is turned off (the ClkWr write pulse is absent), and the transistors Q5 and Q6 are turned on via the ClkEr erase pulse (see also Fig. 6). Thus, the capacitor (C1, C2, C3 and / or C4) discharges to the mass level (e.g. V = 0) or virtual mass (VG), similar to Cint. Again, the Cint capacity mimics the capacity of the Cs sensor. After connecting the capacities Cs and Cint with the mass and discharge, the impulse and the delete cycle are completed. Then another capacitor (C1, C2, C3 or C4) can be prepared, charged and read.

[0112] Referring to Fig. 4 It should be noted that, according to some embodiments of the present invention, the rain sensor comprises: a sensing circuit comprising at least a first and a second sensing capacitor (e.g. C1 and C2) that are sensitive to moisture present on the outer and also at least one capacitor which mimics at least the glass surface processes, mimic (Cint), charge and / or discharge of at least one sensing capacitor, first second; wherein the recording pulse (ClkWr) charges at least the first sensing capacitor (e.g. C1), and the erasing pulse (ClkEr) substantially discharges each of the first sensing capacitor (e.g. C1) and the mimicking capacitor (Cint); with the presence of rain

On the outer surface of the glass in the sensing field of the first sensing capacitor (e.g. C1) causes voltage fluctuations (see Vo or Vout) on the output electrode of the mimicking capacitor (Cint) in proportion to the voltage fluctuation on the output electrode (8) of the first sensing capacitor (on example C1), even though there is no rain in the field of the mimic capacitor (Cint), and rain is also detected on the basis of the output signal (Vo or Vout) from the output electrode of the mimic capacitor (Cint), the output signal being read at least between the end of the recording pulse (ClkWr) and the beginning of the erasing pulse (ClkEr) (see "reading area "In Fig. 6). [0113] Still referring to Fig. 5, in some embodiments of the present invention, during the erase cycle, the erase pulse ClkEr discharges the capacitor (C1, C2, C3 and / or C4) and thus also the Cint mimetic capacitor, to ground (e.g. a fixed potential of V = 0) (see traditional mass symbol in Fig. 5). However, in other embodiments of the present invention, it has been noted that the set mass can lead to some problems. Thus, in these other embodiments of the present invention, during the erase cycle, the ClkEr pulse discharges the capacitor (C1, C2, C3 and / or C4) and thus also the Cint-imitating capacitor to the level of the virtual mass VG that is floating (see VG and the mass symbol in Fig. 5). In other words, the electrode of each of the C1 - C4 capacitors is floating. It may be at floating potential / voltage or reference potential / voltage. In some embodiments of the present invention, it has been noted that a floating or virtual mass can be very beneficial (e.g., a floating mass and / or a capacitor electrode (s) can lead to a significant reduction in problems associated with electromagnetic interference). For example, this type of floating or virtual mass can help reduce risk

In this case, the contact value of the sensor system is mislead by electromagnetic interference. In this regard, reference is made to Figures 28 (a) and 28 (b) (together with Figure 5).

[0114] In Figs. 28 (a) - (b), reference numbers 7 and 8 designate capacitor electrodes (for example C1, C2, C3, C4). In these figures, the symbol "q" refers to charge, and φ refers to potential (φ1 is different from φ2). In Fig. 28 (a), the capacitor (e.g. C1) is grounded at a fixed potential, e.g. zero volt (the charge at grounded electrode 7 is set at + q). In this regard, when the charge of the grounded electrode 7 is set to + q, when an external EB object approaches the sensing capacitor area (e.g. a human finger with a higher dielectric constant) (e.g. touching the front surface of the glass above the capacitor), then this external object induces a charge change ^ q, and the state of the second electrode 8, which is not fixed, changes from the charge -q to the charge q + Δq, trying to balance the charge. So if the capacitor is grounded at a fixed potential, for example zero volt, then when reading the output voltage from the capacitor, the change caused by the change in charge Δq will be read, which is unnecessary and can lead to false readings. By comparing Figures 28 (a) and 28 (b), in Fig. 28 (b) illustrates the benefit of making the sensing capacitor 7 electrode (e.g., any of the C1-C4 capacitors) floating (e.g., floating or virtual ground). In Fig. 28 (b), the charge q at the electrode 7 is not fixed. For example, the charge at electrode 7 varies from + q 'to + q' 'when the external object enters the windshield in the sensing capacitor area, thus indicating the floating nature of the electrode. In fig. 28 (b), when an external object (e.g. a human finger) is applied to the glass in the sensor area of ​​the capacitor, the free charges on both

53 / 59P29195EN00 electrodes 7 and 8 of this capacitor. Thus, the adverse effect of the charge change Δq is eliminated or reduced by the use of a floating or virtual mass (electrode 7 is floating). In particular, when the electrode 7 is floating, as in Fig. 28 (b), the external object (EB) does not adversely affect the charge summation, since the addition of charges (+ q "and -q") of the electrodes 7 and 8 in the presence of this an external object gives zero or essentially zero. Also, false readings due to electromagnetic interference can be reduced by using this floating mass. The floating nature of the electrodes may therefore, in certain example embodiments of this invention, allow the absolute values ​​of the charges q on the capacitor electrodes 7 and 8 to be the same or substantially the same, even if an external object is present because the electrode 7 is floating and is not fixed on mass potential. This is one example of why it can be beneficial to make electrodes 7 of capacitors C1 - C4 fluid or set them on the virtual mass VG, as shown in Fig. 5. Referring to Figs. 5 and 28, sensor capacitors C1 - C4 are floating and both of their electrodes are isolated from ground. As said, according to some embodiments of the present invention, the rain sensor comprises at least one sensing capacitor (C1, C2, C3 and / or C4) which is sensitive to moisture on the outer surface of the pane, the sensing capacitor comprising a first a capacitor electrode (8) that receives a charging signal and a second capacitor electrode (7), distant from the first capacitor electrode (8); the second capacitor electrode (7) of the capacitor is floating, so that the sensing capacitor is isolated from ground.

[0115] Fig. 6 is an exemplary time chart of signals applied or read from the system of Figs. 4-5 during write / delete modes / cycles. As noted

53 / 59P29195EN00 above, capacitors (C1 - C4) are sequentially charged, read, quantized and erased. Fig. 6 shows the clock pulses for recording (ClkWr) and erasing (ClkEr) for each capacitor C1-C4 in sequence. Then the voltages are quantized and output. Variable output voltage Vo1 - Vo4 corresponds to the capacitors C1 - C4, and therefore Cint. It should be noted that the Vo1-Vo4 output signals in Fig. 6 are taken at the Vout (or Vo) level in Figs. 4-5. In addition, in Fig. 6, the output Vo signals are read or analyzed (e.g., for autocorrelation and / or cross-correlation) in the peak read areas (see "Read" in Fig. 6) of the output signals, where the output signals are substantially saturated.

stabilized and / or capacitor, in particular the output signal Vout (or Vo) in Fig. 6 for a specific capacitor (C1) is read in the "reading area" after the write pulse (ClkWr) for this capacitor has ended and before and / or until the start of the pulse reset (ClkEr) for this capacitor.

[0116]

Still referring to Fig. 6, for example, a rain drop on the outer surface of the windshield will affect the size of the output signal (s) Vout (or Vo). For example, a drop of water in the area of ​​a given capacitor (for example C1) will cause the level of output signal (s) Vout (or Vo) for this capacitor in the area of ​​"reading" the signal will be higher compared to the situation of the absence of this drop of water. The exact size or level depends on the size of this drop of water. With increasing amounts of water, the signal size in the "reading" area increases because the dielectric constant of water is higher than that of glass and / or air, which increases the capacity. Similarly, if there is no water droplet on the windshield above the area of ​​a given capacitor (for example C1), then this will cause a decrease in the output level of the signal (s) Vout (or Vo) for this capacitor in the area

53 / 59P29195EN00 "read" compared to if such a drop were present.

[0117] Signals (e.g., from a capacitor (s)) can be converted from analog to digital via a sigma-delta modulation scheme or the like that can be implemented at the program level or in any other suitable manner, e.g. in hardware . The principle behind the sigma-delta architecture is to make rough estimates of the signal, measure the error, integrate it, and then compensate for that error. Data can be oversampled at a given frequency, for example, at least 32 kHz, more preferably 64 kHz, however it should be noted that other sampling frequencies can be used. The quantization run can be reproduced using a sigma-delta modulation scheme to produce a simple binary output 0 or 1 corresponding to the on and off state, respectively. The sigma-delta modulation scheme can therefore be used to reduce noise (e.g. in the tail of a signal) and produce a digital output stream (e.g. ones and zeros).

[0118] Before discussing in detail the work and mathematical model on which the algorithm of an exemplary sensor is based, an overview of the states in which the sensor and / or wipers may be located with reference to Fig. 7 is provided, which is an exemplary state diagram showing how it can be use data related to autocorrelation and cross-correlation to control vehicle wipers. The system starts operating in the S702 Start / Initialization state. In this state, all buffers are cleared, in some example cases. Based on the inputs of the capacitors C1, C2, Cn, analog-to-digital conversion of signals from the respective inputs is performed via sigma-delta modulation. Data are read for many channels in a certain period of time T. Status S704 Mode Selection works as a serving switch

Capacitive matrix autocorrelation. Thirdly, the moisture on the windshield rain indications are such that you can choose between manual or automatic wiper mode. If the status of the S704 Mode Selection indicates that the manual mode is selected, then in the S706 state of the Manual Mode, the automatic mode can be turned off and the pre-existing manual mode activated. Then the system returns to the S702 Start / Initialization state. However, if the Mode S704 of the Mode Selection indicates that the automatic mode is selected, then the automatic mode is turned on in the state S708 of the Automatic Mode.

[0119] At least three calculations are performed in state S710 of the Auto Correlation Engine. First, the normalized autocorrelation is calculated for each signal input. Second, the gradient is calculated, the difference between the signal input and the undisturbed reference signal (Δ1) can be calculated. This information is transmitted to the state S712 Is it raining ?, in which at least three conditions are checked to see if it is possible that it is raining, occurring and the like. It is likely that the autocorrelation gradient is greater than 1, all autocorrelation values ​​are positive and / or the Δ1 value is greater than some predetermined threshold t1. If these conditions are not met, the system goes to the S714 Park Wipers / Stop state

The engine in which the wipers are parked (if they are just moving) or not starting, and the engine is stopped (if it is just running) and the system returns to the S702 Start / Initialization state.

[0120] On the other hand, if all the conditions are met (for example, it is likely that there is water, moisture or other disturbance on the glass, etc.), the system goes into the S716 Smallest Speed ​​state in which the wiper motor is started with the smallest possible available speed. In condition S718 Engine

53 / 59P29195PL00

Cross-correlation is calculated cross-correlation between input signals from capacitors. The shape of the cross-correlation curve is determined and the symmetry of both sides of the cross-correlation curve is checked. As will be described below, these checks help, for example, to determine the type of disturbance (e.g. light rain, heavy rain, fog, snow and the like) encountering a windshield (e.g. windshield) standing

S720

Estimate for example

Precipitation intensity is determined by "intense, light" precipitation level and the like). Based on this determination, the S722 Speed ​​Selection state starts the engine at the appropriate speed. Eventually the system returns to the S702 Start / Initialization state to determine if there have been any changes in the conditions outside the car.

[0121] The steps performed by the rain sensor will be described in more detail with reference to Fig. 8, which is an exemplary flow chart showing how autocorrelation and cross-correlation data can be used to control the wipers in certain example embodiments of this invention. In Fig. 8, the buffers are cleaned in step S800 and the data generated in the system of Fig. 4-5 (for example from Cint or from C1 to C4 capacitors) are subjected to Sigmadelt modulation and are read in step S802.

[0122] An algorithm for determining whether wipers should be turned on and, if so, at what speed, is started by autocorrelating the data in step S804 subjected to sigma-delta modulation. Auto-correlation can be used to analyze a function or series of values, for example signals in the time domain. Autocorrelation is a cross-correlation of a signal with itself. Autocorrelation is used to find repetitive or substantially repetitive patterns in a signal, such as, for example, determining the presence of a periodic signal hidden in noise, identifying

A fundamental frequency signal that actually does not contain this frequency component, but is suggested by the content of multiple harmonic frequencies, and the like. Cross correlation is a measure of the similarity of two signals and is used to find properties in an unknown signal by comparing it with a known signal; in other words, in some cases it can be used to perform signal discovery of similar fingerprint characteristics. Cross-correlation is a function of the relative time between signals. In certain example embodiments of this invention, digital signals from any two capacitors (e.g., C1 and C2) are cross-correlated in close spatial proximity, and the system looks for any degree of correlation with non-zero time delays. This type of space-time cross-correlation allows the system to extract patterns like electrically, falling rain, projecting itself onto the sensor matrix. For example, this system may take the case of raindrops moving over one capacitor C1 at the time t0 and the same droplet "hitting" another capacitor C4 (spaced at a distance L from the capacitor C1). If this drop moves at an average speed of Vi, time (t0 + T), where T = L / Vi, the cross-correlation function will have another extreme or bend. The normalized amplitude for this extreme value may allow the system to determine the degree of intensity of rain falling on the sensor.

[0123] Each capacitor C1 - C4 has an autocorrelation function associated with the digitized voltage Vout resulting from its reading (or the corresponding Cint reading). In an embodiment, the autocorrelation function depends on the time difference rather than the actual time. Calculation of autocorrelation is advantageous because it allows, for example, to deduce the basic frequency regardless of phase.

53 / 59P29195PL00

Auto-correlations have an advantage over other methods, such as Fourier transforms (which can also be used in some embodiments of the present invention) that only provide information about harmonic content. The use of autocorrelation for readings from C1 - C4 capacitors (which, as explained above, includes appropriate readings from a Cint mimetic capacitor) can be used to detect and distinguish between water, dirt, dust, droplets, droppings and the like.

[0124] It should be noted that in this document, the data from the Cint capacitor is considered to be data from the C1 - C4 capacitors, since the capacitance Cint mimics or substantially mimics the capacities of C1 - C4, as explained above. So, when we talk about receiving data from capacitors (for example C1 - C4) this refers to and includes receiving data from Cint capacity. In other words, for the output of the system from Fig. 4 - output from C1 - C4 capacitors is considered to be even if this signal is not taken directly from them.

[0125] Rain as a function of time can be represented by the following formula:

the rain casts electrically ₀ otherwise

Basically b takes a binary value indicating whether it is raining (1) or not (0). It should be noted that b contains at least two bits and that 24 bits can be used for sigma-delta modulation, in some embodiments. It should also be noted that a scale can be introduced, potentially to capture more voltage related data on capacitors C1 - C4 (or Cint).

[0126] At the end of the sampling cycle L, for example, the output of the system of Figs. 4-5, for example from a matrix of four b (r, Z) = &lt;

The capacitors C1 - C4 (or via Cint) are in the range of 0000 to 1111, in some embodiments, using digital binary data. In some example cases, a single enabled bit may initiate wiper operation. In the event that all bits are turned off (0000) or all bits are turned on (1111), the wipers cannot be initiated, in some example cases, because there is probably nothing on the windshield, the car is completely covered with water and the like, because all capacitors in the matrix read the same, which does not correspond to rainfall on the glass. So the most likely events where wipers will be needed are those in the range from 0001 to 1110 (that is, when the outputs of all capacitors in the matrix are not the same). When the data have a value in this range or are not even in this range, correlation functions (autocorrelation and / or cross-correlation) can be performed using the following integral. It should be noted that the integral below may be written in a different form, for example in the form of a sum. Correlations between two drops over a long period of time can be calculated according to the following formula:

₁L ^Rb ((vol ^t2 ) = 7 J ^t1 + ^tt2 + ^t)^dt^L₀^Rb (( ^{t; t}2 )= ^Rb ( ^Δ) where Rb is the correlation of the binary event, given as a function of resistance ri in given time moments ti; and L is the long sampling period during which the data sequence is captured. In some embodiments, the sampling period L may be from about 10 to 100 ms, and more preferably from about 20-30 ms, which corresponds to approximately the average frequency that can be distinguished by the human eye. rb

53 / 59P29195EN00 is also equal to the function of correlation of changes in resistances on Ar capacitors and time change. When Ar = 0, the autocorrelation value is determined because data from the same capacitor is analyzed, and if Ar A 0, then cross-correlations are calculated on data from different capacitors.

[0127] These functions are subject to several examples of limitations and assumptions. First:

Ar = Vi Δt

This limitation generally means that a drop of water or similar disorder travels over a given time scale. Secondly:

b (r + Vi At, t + At) = b (r, t).

This limitation mimics or essentially mimics what happens when water droplets or the like move from one capacitor to another. Therefore, correlation functions can be considered as discrete stages p in space and T in time. This property can be mathematically represented by the following equation:

R_b (mp, nT) ξ R (Vi At, At)

Basically, the left side of this equation establishes a theoretical grid in space and time over which a drop of water travels. For example, Fig. 9 is an exemplary stylized view of how a rain droplet may move. Fig. 9 shows a rain drop moving on the windshield in the XZ plane during the initial period of time (t = 0) and at some later period of time (t = T). The assumption that the distribution of drops is homogeneous in space and time allows the creation of a binary field created by rain, which is broadly stationary. This system also assumes that the time correlation between preferred pixels in the same neighborhood is high in the direction of rain. Finally, the degree of autocorrelation and cross-correlation over time quantizes rainfall and other disorders.

[0129] It should be noted that in some embodiments, computation time can be saved due to the nature of the correlation matrix and the nature of rainfall. For example, correlation matrices may be symmetrical in some example cases. In addition, as another example, due to the fact that the rain tends to fall from the sky and move up the windshield, it may be sufficient to compare only capacitors that are arranged vertically with respect to each other in cross-correlation, while ignoring adjacent capacitors level.

[0129] It should be noted that although binary data is used in some embodiments of the present invention, grayscale data can also be used in the present invention in certain example cases with respect to the outputs of the system of Figs. 4-5 or the like, or other appropriate system (s).

[0130] After performing autocorrelation at step S804 (for example, using the equations discussed above or other useful correlation equations), one or more checks may be performed to increase the system accuracy. Examples of this type of check (e.g., if the Rxx autocorrelation data has negative values, if the gradient is greater than one and / or the shape of the Rxx curve is different or substantially different from the non-disturbed normalized autocorrelation data stored in memory) are listed at the bottom of the frame of step S804 on Figure 8. One, two or all three of these checks can be performed.

[0131] For example, one check of autocorrelation data in step S806 may aim to determine whether autocorrelated data from one or more capacitors (C1, C2, C3 and / or C4; or via a Cint mimetic capacitor) contain negative values. For example, when autocorrelated data contain negative values, then the system or method may indicate that there is no rainfall, park

Wipers and / or do not operate the wipers (see step S808). This test is intended to determine, for example, whether the detected disorder is actually rainfall. To this end, Fig. 10 is a graph of sample experimental data for maximum values ​​of non-normalized autocorrelation for various disorders. In fig. 10 it has been shown that the water signals are greater than the positive signals and they are positive, and that external interference such as electromagnetic waves from the CB radio and human touching the windshield are usually below undisturbed levels and can be negative. Thus, in order to eliminate or reduce false detections due to external disturbances, such as human touch glass, radio signal interference and the like, any signal with negative autocorrelation values ​​is considered a "no rain" event. It should be noted that negative autocorrelation values ​​may be considered in some embodiments. In other embodiments, other measures may be taken to eliminate or reduce false detections due to external interference by, for example, comparing gradients (for example, any curve lower or smaller than the undisturbed curve / graph of Figure 10, may be considered a "no rainfall "), capacitor sheathing and other activities.

[0132] A second example test of autocorrelation data is to check if the autocorrelation curve gradient associated with autocorrelated data is greater than one, and if this is not the case, then the system or method may indicate that there is no rainfall, park the wipers and / or do not start vehicle wipers (see step S808). For this test, the normalized autocorrelation gradient of the disorder is checked. The gradient of the normalized autocorrelation of the undisturbed signal is close to one. Gradient measurement is beneficial because it is not affected by temperature change. The rain sensor can therefore be basically

It is resistant to false readings resulting from temperature changes in certain example embodiments of this invention. In some example instances, gradients with a value less than 1 (or some other predetermined value) can be considered as non-rainy events.

[0133] A third example test of autocorrelation data is whether there is a match or substantial match between the autocorrelation curve (e.g. signal footprint) associated with the autocorrelated data and one or more predetermined autocorrelation curves (e.g. specific signal footprint) present in the database and / or memory. When the shape of the autocorrelation curve associated with the autocorrelation data of the system of Fig. 4 - 5 is different or substantially different from the autocorrelation curve associated with normalized undisturbed autocorrelation data, this can be considered a non-rain event and it can be indicated that there is no rainfall, the wipers may be parked and / or the wipers may not be activated (see step S808). However, when there is a match or substantial match between the autocorrelation curve associated with the autocorrelation data of the system of Fig. 4 - a predetermined autocorrelation curve related to the presence of moisture, for example rain, then it can be said that it is actually raining, the wipers can be activated or kept in motion.

[0134] In this regard, the shape of the autocorrelation curve can be used to reduce false wipes and / or false detections. In particular, normalized autocorrelation of a non-disturbed signal is used as a reference. Then, the normalized autocorrelation of each signal measured in the circuit of Figs. 4-5 is compared with a reference to identify the closest fingerprint in some example cases. Basically, the more water there is in the area

The greater the difference between the reference signal and the observed signal is the measurement. This allows you to compare correlation snapshots with reference snapshots of well-known events, such as the presence of rain, dirt, no disturbance, ice and so on. In general, correlation snapshots can be normalized, although the invention is not limited to this. In certain example embodiments of this invention, the correlation snapshots preferably plot r values ​​as a function of time quanta over a discrete time interval.

[0135] In some embodiments, when there is a match or substantial match between the autocorrelation curve associated with the autocorrelated data derived from the Fig. 4-5 system and the predetermined autocorrelation curve associated with the non-moisture substance such as dirt, then this can be considered a non-rainy event and it can be concluded that there is no rainfall, the wipers can be parked and / or not activated (see step S808).

[0136] It should therefore be noted that the shape of the autocorrelation curve resulting from data derived from the circuit of Figs. 4-5 (from capacitors C1-C4 or via Cint) can be used to reduce false wipes as a third condition. For example, a normalized autocorrelation curve of a non-disturbed signal can be used as a reference. Then normalized autocorrelation of each signal taken from the circuit of Fig. 4 - 5, is compared with a reference to identify the closest fingerprint type. Generally, the more water is present in the sensor area, the greater the difference between the reference signal and the observed / measured signal. This allows correlation snapshots to be compared with reference snapshots of well-known events. In general, correlation snapshots are preferably normalized, however, the invention is not this way

Limited. Correlation snapshots favorably plot r values ​​as a function of time quanta over a discrete time interval. [0137] A potential problem with capacitive rain sensors is that rapid temperature changes (for example, due to the use of a black-absorbing frit used to cover the sensor pattern cosmetically) cause a change in the "constant" dielectric (permittivity) of the glass. This is then recorded as a change in capacity and may be misinterpreted as a rain signal. However, according to some embodiments of the present invention, the normalized autocorrelation function is unchanged or substantially unchanged at different temperatures even though there may be differences for non-normalized autocorrelation functions at different temperatures. Thus, in certain example embodiments of this invention, the sensor system is unaffected or substantially unaffected by temperature changes.

[0138] In addition, extremely small water accumulation, such as ultra fine mist, for example, can slowly rise to a level that will turn on sensors based on Nyquist frequency converters. During observation, which is associated with human vision (e.g., 30-60 Hz), the autocorrelation function is able, in some embodiments of the present invention, to distinguish between ultra slow mist or condensation accumulation and normal fog and rain.

[0139] Figures 11A-11D illustrate example experimentally obtained correlation snapshots. These correlation snapshots or event fingerprint / footprint characteristics can be stored as footprints / fingerprint reference characteristics or correlation curves. Observed / measured correlation snapshots (for example, autocorrelation curves) can be compared to these "footprint" or "fingerprint" characteristics to determine the type

The occurring event. For example, Fig. 11A is an experimental autocorrelation snapshot indicating heavy rain. Fig. 11B shows an experimentally obtained autocorrelation snapshot indicative of a light fog. Fig. 11C is an experimental autocorrelation snapshot indicating interference with a CB radio signal. Figure 11D shows an experimentally obtained autocorrelation snapshot indicating a grounded object with voltage. The data patterns in Figures 11A-11D may be named in some cases with predetermined footprints or fingerprints, and it should be noted that other types and shapes of predetermined footprints may also be used in other examples embodiments of the present invention. It should be noted that these "footprints" / "fingerprints" characteristics are given as non-limiting examples and reflect experimental data. Actual events can differ in many ways. Thus, in some embodiments of the present invention, if it is determined that there is a match or substantial match between the autocorrelation curve associated with the autocorrelation data from the perimeter of Figs. 4-5 and the predetermined non-moisture related autocorrelation curve, such as Fig. 11C or fig 11D, then it can be considered a non-rain event and it can be concluded that there is no rainfall, the wipers can be parked and / or not activated (see step S808). However, in some embodiments of the invention, if it is found that there is or a substantial match between the autocorrelation curve associated with the autocorrelated data from the circumference of Figs. 4-5 and the predetermined autocorrelation curve associated with the presence of moisture, such as Fig. 11A or FIG. 11B, then it can be considered a rainy event and it is raining, the wipers can be turned on and / or kept in motion. In addition to the predetermined curves of this fit

The autocorrelation of Figures 11A-11D may store other fingerprint characteristics and / or compare them with observed correlation snapshots in other example embodiments of this invention.

[0140] Returning to Fig. 8, it is determined in step S808 that each of the three conditions shown at the bottom of frame S804 are met. In particular, it is ascertained at step S806 that each of the following conditions is met: (a) the autocorrelated data does not contain negative values; (b) the autocorrelation curve gradient associated with these autocorrelated data is greater than a predetermined value, for example one; and (c) whether the shape of the autocorrelation curve associated with the autocorrelated data of the perimeter of FIG. 4 - 5 is different from the predetermined autocorrelation cams associated with undisturbed autocorrelation data. If all of these conditions are not met, then this suggests a non-rain event and the process proceeds to step S808, in which the vehicle wipers are parked (if they were moving) or kept off and the S800 initialization begins again. However, if all these requirements are met at step S806, then the process proceeds to step S810 and the wipers of the vehicle (e.g., windshield wiper) are operated at the lowest speed.

[0141] For the purpose of example only and for understanding, Fig. 13 shows an example of autocorrelation. In Fig. 13, the values ​​from (or associated with) the sensor capacitor C1 occurring at subsequent moments -t2, -t1, t0, t1, t2, and t3 have the values ​​0, 0, 1, 1, 0, and 0. Autocorrelation for the moment 0 (aco) is determined by multiplying the values ​​associated with the capacitor C1 without offset, and then adding or adding up the results. In fig. 13 it can be seen that aco is 2 in this case. Accordingly, in the autocorrelation chart at the bottom of Fig. 13, the entry for time 0

In a similar 13, it performs the next one by means of an autocorrelation value of 2. It should be noted that the autocorrelation plot at the bottom of Fig. 13 is similar but simpler than the autocorrelation plot in Fig. 10 and the autocorrelation values ​​can be obtained for Fig.

way. Then, still referring to fig.

autocorrelation using the capacitance values ​​associated with the C1 capacitor for the next point in time to obtain the ac1 autocorrelation value. This autocorrelation value (ac1) is obtained by shifting the value sequence for capacitor C1 from the bottom row relative to the top row as shown in Fig. 13, and then multiplying the values ​​in those lines that were in one line and adding up the results. In fig. 13 it has been shown that the value of ac1, for the moment 1, is 1. Therefore, this autocorrelation value of 1 for the moment t1 can be entered on the graph at the bottom of Fig. 13 and a line can be drawn between the two entered data points to illustrate an example and understanding . Then, for the next time value (or time delay), the bottom row is again shifted by another segment relative to the top row and this process is repeated and so on. It can be seen that the autocorrelation plots in Fig. 10 can be obtained in a similar manner. In Fig. 13, it can be seen that cross-correlation can be performed by replacing the values ​​associated with the C1 capacitor in the bottom row with values ​​derived from or associated with another capacitor, for example C2 (or C3 or C4).

[0142] Autocorrelation and / or cross-correlation testing can also help distinguish between, for example, light rain and heavy rain. For example, if only the autocorrelation in time is high (while the cross-correlation is low), then there is probably only light rain. Fig. 12A is an example correlation matrix showing light rain. In Fig. 12A, it is important that the correlations between

53 / 59P29195PL00

C1 and C1, C2 and C2, C3 and C3 and C4 and C4 (these are autocorrelation) in a given cross period) are correlations (hypothesis correlations and are large, and the rest are small. As a result of confirmed experimental data, this type of matrix will show a light rain.

[0143] On the other hand, if both the autocorrelation and cross-correlation in time between the capacitor signals are high, there is probably heavy rain. Fig. 12B is an example correlation matrix showing heavy rain. In fig. 12B not only are the autocorrelation of individual capacitors high (i.e., autocorrelation are correlations between capacitors C1 and C1, C2 and C2, C3 and C3 and C4 and C4), but also the correlations between different capacitors are high (correlations of Fig.

located on the diagonal from the upper left lower right corner are autocorrelations, while the remaining rain intensities. including various

12B to are cross-correlations). As a result of hypothesis and confirmation with experimental data, this type of matrix will indicate heavy rain. The degree of cross-correlation can be quantized to determine the relative. These data can in turn be used for wiper speeds appropriate to the intensity of the rain. For example, the more cross-correlations that are large, the higher the wiper speed used.

[0144] More systematically, at step S812, cross-correlations (correlations between data associated with different capacitors) are calculated, and both sides of the cross-correlation curve are used to determine the level of symmetry L. If the level of symmetry is below a predetermined threshold tmin , step S814 directs the system to step S816, where the wipers are run at the lowest speed and the system returns to initialization at step S800. If the level of symmetry is greater than tmin, but less than arbitrary

In t values, step S818 directs the system to step S820, where the wipers are operated at a higher or medium speed and the system returns to the initialization step S800. Note that many arbitrary ti values can be specified , and a symmetry level between ti and ti + 1 will run the appropriate wiper speed and then return the system to the S800 initialization stage. Finally in step S822, if the symmetry level is greater than the predetermined value tmax, step S822 directs the system to step S824, where the wipers are operated at the highest speed and the system returns to the initialization stage S800. Correlations of the output data of the circuit of Figs. 4-5 can therefore be used to adjust the wiper speed. In some embodiments, the more high cross-correlations there are, the higher the wiper speed used because of the greater the likelihood of heavy rain. [0145] For example and for understanding, Figs. 14-24 are examples of cross-correlation performed in accordance with some embodiments of the present invention. Fig. 14 shows the data subjected to cross-correlation in some example cases, while Fig. 15 24 is a cross-correlation graph of some of the data in Fig. 14 where rain is detected. In Figs. 15-24, each interval on the horizontal axis is one microsecond (1 μβ) for the purposes of the example, and sampling was performed every one microsecond. As explained above with reference to Fig. 13, in Figs. 15-24 at a time = 0 (delay 0) there is no time offset of correlated values ​​from different capacitors. In fig. 14 it was illustrated that when rain was present (see signals S1 - S5 and W1 - W5), the delta signals regarding autocorrelation were large. Fig. 24 24 are cross-correlation plots associated with these signals. It is helpful to find symmetry between the graphs on the left and right of each of Figs. 15 (one side of zero is compared to the other side of zero). Generally speaking, if there is symmetry around the zero delay axis, there is not much cross-correlation, indicating that the detected rain is not very intense. However, if there is asymmetry around the zero delay axis, this means more cross-correlation and indicates the presence of heavy or more intense rain. For example, you can see the asymmetry in Figs. 18, 19 and 23 around the zero axis as a result of humps or valleys on one or both sides. More cross-correlation indicates that raindrops are moving from the sensing area of ​​one capacitor to the sensing area of ​​another capacitor. In this respect, each interaction of a raindrop and windshield surface has its own time-domain correlation signature. A high cross-correlation value indicates that the same droplet is detected by different capacitors at different times (for example, see also Figure 9). It should be noted that the lower case letter "t" in Fig. 9 is the same as the delay axis in Figs. 15-24.

[0146] It should be mentioned that in some embodiments of the present invention there is provided a moisture sensor (e.g. a rain sensor) that can detect rain or other substance on the vehicle window or other type of window or sheet / surface without the need for a reference capacitor. Spatial-time correlation can be used. All capacitors or multiple capacitors in a sensor matrix may be identical or substantially identical in shape in some embodiments. For example purposes, at a given point in time (e.g. t1), the system may compare the values ​​associated with the C1 capacitor with the values ​​associated with the C2 capacitor and / or the values ​​associated with another capacitor. At the moment t1, the system can also compare values ​​related to the C1 capacitor with itself (autocorrelation) and can also compare autocorrelation

53 / 59P29195EN00 for a C1 capacitor with autocorrelation for a C2 capacitor and / or other sensor capacitor).

[0147] In the figures of the sensor other capacitors

4-5 show switches to selectively connect various C1-C4 capacitors to the rest of the circuit, and the context to read in Figure 26 shows the multiplexer including

The circuit shown in Figures 4-5 and / or 26 can signals from all C1-C4 capacitors simultaneously, or alternatively can read signals from only one capacitor at a time, selected from among C1-C4 capacitors, or as an additional alternative, can read signals from a combination some, but not all C1C4 capacitors at a given point in time. An example of a non-limiting switching circuit for selectively connecting the reading electronics to one or more C1-C4 capacitors depending on needs or requirements is discussed below with reference to Figure 31. The switching circuit shown in Figure 31 or the like may, but it need not be used instead of the switches shown in figures 4-5 and / or the multiplexer shown in figure 26.

[0148] Figure 31 shows an exemplary switching circuit, for selectively connecting or switching between different C1-C4 sensing capacitors or other combinations thereof, for sensing and / or changing the analyzed area of ​​the searched feature. Thus, the switching circuit depicted in Figure 31 allows the sensing area (s) and / or the system to be selectively reconfigurable in certain example embodiments of this invention. For example, in some embodiments, the switching circuit may selectively switch between: (a) a sensor (s) (e.g. C1) for detecting rain on the outer surface of the window, and (b) a sensor (s) (e.g. one or more) number C2, C3 and / or C4) for detecting one or more positions

Of: ice on the outer surface of the window, fog on the outer surface of the window and / or moisture on the inner surface of the window. The readout circuit (readout circuits) can read signals from all C1-C4 capacitors simultaneously, or alternatively it can read signals from only one capacitor at a time, selected from among C1-C4 capacitors, or as an additional alternative, it can read signals from a combination of some, but not all C1C4 capacitors at a given point in time; The switching circuit depicted in the figure and these capabilities allows each of the selective calls to be implemented, depending on the requirements. Thus, the switching circuit depicted in figure 31 may be advantageous in that it can allow the system to be selectively adapted, via a sensor area, to focus on different types of elements (e.g. rain, ice, fog, etc.) in different points in time. The C1-C4 capacitors may or may not have the same fractal pattern or geometry, and may or may not have different shapes and / or sizes in different cases.

[0149] The switching circuit shown in figure 31 includes a power source connection at an RFC point, control connections at a CTRL1 point

CTRL2, inverters IV1

IV2, logical product gate G and switches SW1, SW2, SW3,

Sw1-SW8 switches can be (MEM) in which

MEM causes that

SW4, SW5, SW6, SW7 and SW8 with microelectromechanical switches applying voltage to the switch, the switch is activated, or another type of suitable example with it two switch in different cases. performance, each capacitor has associated switches. For example, the sensor capacitor C1 (and / or band 1, if the sensor device is an antenna instead of a capacitor) has associated switches SW1 and SW2, the sensor capacitor C2 (and / or band 4, if the sensor device is an antenna instead of a capacitor) has instead capacitor)

53 / 59P29195EN00 associated switches SW3 and SW4, sensor capacitor C3 (and / or band 4, if the sensor device is an antenna instead of capacitor) has switches SW5 and SW6 associated with it, and sensor capacitor C4 (and / or band 4, if the sensor device is an antenna instead of a capacitor) has switches SW7 and SW8 associated with it. In figure 31, for the purposes of example, switches SW2, SW4, SW6 and SW7 are illustrated in a closed position, while switches SW1, SW3, SW5 and SW8 are illustrated in an open position.

[0150] Sw2, SW4, SW6 and SW8 switches are provided for the selective combination of capacitors C1-C4 (and / or Bands 1-4) with GND ground. In some embodiments, when the capacitor in question is connected to the read circuit (e.g., the capacitor C4 is connected to the read circuit in Figure 31 because the SW7 switch is closed), this capacitor is disconnected from the GND ground by opening its ground switch (e.g. ., the ground switch SW8 is open in figure 31). However, when a given capacitor (capacitors) is not connected to the reading circuit, (e.g., the capacitors C1, C2 and C3 are not connected to the reading circuit in Fig. 31, because the associated reading switches SW1, SW3 and SW5 are open), then this capacitor is grounded by closing its grounding switch (e.g., the ground switches SW2, SW4 and SW6 are closed to ground the capacitors C1, C2 and C3, respectively, in figure 31). Grounding capacitors not read at the moment is beneficial in this interference with the switching read circuit by noise and / or other problematic signals. [0151] Referring still to Figure 31, for the purpose of example and without limitation, an example situation in which the capacitor C1 is designed (e.g. shaped) and located to the outer surface of the window (e.g.

respect that prevents or the entire rain detection circuit on the windshield of the vehicle),

The C2 capacitor is designed and located for detecting ice on the outer surface of the window, the C3 condenser is designed and located for detecting fog on the outer surface of the window, located for the window surface, and the C4 capacitor is designed and detecting steam / moisture on the inner (e.g. . if the capacitor C4 detects such vapor and / or moisture on the inner surface, then the defroster can be switched on automatically or in another case for preventive purposes).

In exemplary cases, each of the capacitive C1-C4 may have a different fractal pattern and / or shape, and / or a different orientation / direction. The switching circuit, in order to focus the reading circuit on detecting rain outside the window surface, can connect

In some such fractal sensors, the capacitor C1 isolate the capacitors with a reading circuit

C2-C4 from the reading circuit; this can be done by sending control signals CTRL1

CTRL2, which close the switches SW1, SW4, SW6 and SW8 and open the switches SW2, SW3, SW5 and SW7. In another example, the switching circuit, in order to focus the read circuit on detecting steam and / or moisture on the inner surface of the window, can connect the C4 capacitor to the read circuit and isolate the C1-C3 capacitors from the read circuit; this can be done by sending control signals CTRL1 and CTRL2 that close the switches SW2, SW4, SW6 and SW7 and open the switches SW1, SW3, SW5 and SW8, as shown in figure 31. In another example, the switching circuit, in order to focus the read circuit on detecting fog on the outer surface of the window, can connect the C3 capacitor to the read circuit and isolate the capacitors C1, C2 and C4 from the read circuit; this can be done by sending control signals CTRL1 and CTRL2, which close the switches SW2, SW4, SW5 and SW8 and open the switches SW1, SW3, SW6 and SW7. In yet another example, the circuit

In order to focus the reading circuit on detecting both ice and rain on the outer surface of the window, it can connect the C1-C2 capacitors to the reading circuit and isolate the C3-C4 capacitors from the reading circuit; this can be done by sending control signals CTRL1 and CTRL2 that close the switches SW1, SW3, SW6 and SW8 and open the switches SW2, SW4, SW5 and SW7. It is also possible in some example cases to connect all C1-C4 capacitors with the reading circuit, in which case the switches SW1, SW3, SW5 and SW7 would be closed and the switches SW2, SW4, SW6 and SW8 would be open.

[0152] It should be noted that the switching circuit of Figure 31 may or may not be used in combination with any other embodiment discussed herein.

[0153] Furthermore, it is possible but not claimed that the C1-C4 capacitors in combination with the embodiment of figure 31 can be replaced by antennas, such as fractal based antennas having respective bands (see bands 1-4 in figure 31) . Thus, in this situation, the circuit of Figure 31 will be able to selectively reconfigure fractal-based antennas with different bands to selectively change the band (s) read by the readout circuit. In such exemplary cases, the read circuit may be used to detect and / or process incoming waves such as AM, FM, Bluetooth, GPS, VHF, and / or UHF signals.

[0154] It should be noted that the use of the word "fractal" in this document is not limited to an ideal fractal pattern, but also includes quasi-fractals, such as polygonal elements and geometric patterns having self-similarity, as discussed in, for example, US Patent Nos. 6,809,692 , 6,937,191, and / or 7,015,868.

[0155] It should be noted that although C1-Cn capacitors (where n is two, four, ten or other suitable number) are preferred as sensor devices in some embodiments of the present invention, it is possible to use other types of sensor devices instead or in addition to capacitors in some example cases. [0156] Although the invention has been described in connection with the most practical and preferred embodiment contemplated, it should be understood that the invention is not limited to the embodiment shown, but on the contrary is intended to include various modifications and equivalent arrangements within the scope of attached reservations.