Rain sensor with fractal capacitor(s)
First Claim
1. A moisture sensor comprising:
- a sensing circuit comprising at least a first sensing capacitor supported by a window, the first sensing capacitor being sensitive to moisture on an external surface of the window;
the first sensing capacitor having first and second spaced apart capacitor electrodes that are substantially coplanar;
wherein the first and second capacitor electrodes of the first sensing capacitor each have a meandering shape and are substantially parallel to each other; and
means for autocorrelating data relating to and/or from the sensing capacitor to obtain autocorrelated data, and means for determining based at least on said autocorrelated data whether moisture is present on the external surface of the window.
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Accused Products
Abstract
A system and/or method for sensing the presence of moisture (e.g., rain) and/or other material(s) on a window such as a vehicle window (e.g., vehicle windshield, sunroof or backlite). In certain example embodiments of the invention, at least one sensing capacitor is supported by a window such as a vehicle windshield, the capacitor(s) having a field that is affected by moisture (e.g., rain) on a surface of the window. The at least one sensing capacitor may have a fractal geometry in certain example embodiments of this invention. The sensing circuit may output an analog signal that is based on and/or related to the sensing capacitor(s). The analog output of the circuit may be converted to a digital signal, and subjected to processing (e.g., correlation) for determining whether moisture (e.g., rain, dew, fog, etc.) or the like is present on the surface of the window.
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Citations
20 Claims
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1. A moisture sensor comprising:
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a sensing circuit comprising at least a first sensing capacitor supported by a window, the first sensing capacitor being sensitive to moisture on an external surface of the window; the first sensing capacitor having first and second spaced apart capacitor electrodes that are substantially coplanar; wherein the first and second capacitor electrodes of the first sensing capacitor each have a meandering shape and are substantially parallel to each other; and means for autocorrelating data relating to and/or from the sensing capacitor to obtain autocorrelated data, and means for determining based at least on said autocorrelated data whether moisture is present on the external surface of the window. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A moisture sensor comprising:
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a sensing circuit comprising at least a first sensing capacitor supported by a window, the first sensing capacitor being sensitive to moisture on an external surface of the window; the first sensing capacitor having first and second spaced apart capacitor electrodes that are substantially coplanar; wherein the first and second capacitor electrodes of the first sensing capacitor each have a meandering shape and are substantially parallel to each other; and programmable logic circuitry for autocorrelating data relating to and/or from the sensing capacitor to obtain autocorrelated data, and for determining based at least on said autocorrelated data whether moisture is present on the external surface of the window. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A moisture sensor comprising:
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a sensing circuit comprising at least a first sensing capacitor supported by a window, the first sensing capacitor being sensitive to moisture on an external surface of the window; the first sensing capacitor having first and second spaced apart capacitor electrodes that are substantially coplanar; wherein the first and second capacitor electrodes of the first sensing capacitor each have a meandering shape and are substantially parallel to each other; at least one mimicking capacitor that mimics at least charging and/or discharging of the first sensing capacitor, wherein a writing pulse causes at least the first sensing capacitor to be charged and an erasing pulse causes each of the first sensing capacitor and the mimicking capacitor to substantially discharge; wherein presence of moisture on the external surface of the window in a sensing field of the first sensing capacitor causes a voltage at an output electrode of the mimicking capacitor to fluctuate in a manner proportional to fluctuation of voltage at an output electrode of the first sensing capacitor, even though the rain is not present in a field of the mimicking capacitor; and wherein moisture is detected based on an output signal from the output electrode of the mimicking capacitor, wherein the output signal is read at least between an end of the writing pulse and a beginning of the erase pulse.
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Specification