Windshield moisture sensing control circuit
First Claim
1. A vehicle windshield rain sensor comprising:
- emitter means for periodically emitting light radiation;
first sensor means for detecting a portion of the radiation refracted and reflected by a windshield and producing a first signal indicative thereof;
second detector means for detecting a portion of the radiation from said emitter means and producing a second signal indicative thereof;
signal-processing means for processing the first signal, said signal-processing means including first amplifier means for amplifying the first signal, filter means for removing the noncyclical component from the amplified signal, and second amplifier means for amplifying the filtered signal, whereby the noncyclical portion of said signal due to ambient light impinging on said first sensor means is removed from the first signal and the cyclical portion is amplified; and
control means for processing the first amplified signal from said signal-processing means and the second signal to provide a decision signal indicative of the amount of moisture on the windshield.
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Accused Products
Abstract
The specification discloses a modulated optical moisture sensor control circuit for a vehicle windshield wiper. The control system includes a first detector providing a signal indicative of moisture on the windshield and a second detector providing a reference signal indicative of system variables, such as ambient light. The control system includes improved circuitry for separating the steady-state portion of each detector signal due to ambient light from the modulated infrared IR signal. The system further includes a sensitivity adjustment accessible by the vehicle operator to alter the sensitivity of the circuit to at least one of the two variable detector signals. Additionally, the control system cooperates with a conventional off/intermittent/on wiper switch so that the wiper is responsive to the moisture sensor only when the conventional switch is in the intermittent position and a second manually actuated switch indicates preferred operation in the moisture sensor mode.
285 Citations
17 Claims
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1. A vehicle windshield rain sensor comprising:
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emitter means for periodically emitting light radiation; first sensor means for detecting a portion of the radiation refracted and reflected by a windshield and producing a first signal indicative thereof; second detector means for detecting a portion of the radiation from said emitter means and producing a second signal indicative thereof; signal-processing means for processing the first signal, said signal-processing means including first amplifier means for amplifying the first signal, filter means for removing the noncyclical component from the amplified signal, and second amplifier means for amplifying the filtered signal, whereby the noncyclical portion of said signal due to ambient light impinging on said first sensor means is removed from the first signal and the cyclical portion is amplified; and control means for processing the first amplified signal from said signal-processing means and the second signal to provide a decision signal indicative of the amount of moisture on the windshield. - View Dependent Claims (2)
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3. A moisture-responsive control system comprising:
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a detector means for detecting a signal having a modulated portion indicative of the amount of moisture on a transparent panel and an unmodulated portion unrelated to the amount of moisture on the panel, said detector means emitting a first signal indicative of the combined portions; a signal processor for amplifying and filtering the first signal, said signal processor comprising a pair of amplifier stages and a filtering stage therebetween for removing the unmodulated portion of the signal; a reference detector means for detecting the unmodulated portion only and emitting a reference signal indicative of the unmodulated portion; and control means connected to the outputs of said signal processor and reference detector means and responsive to the outputs of said signal processor and said reference detector means for generating a control signal as a function of the combined signals existing the signal processor and the reference signal. - View Dependent Claims (4)
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5. A windshield wiper control assembly responsive to moisture on a vehicle windshield comprising:
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emitter means for emitting electromagnetic radiation toward the windshield; first detector means for detecting radiation as refracted by said windshield from said emitter means said first detector means also varying as it is influenced by ambient sources of energy, said first detector means producing a first signal responsive thereto; second detector means for detecting radiation impinging directly thereon from said emitter means and also varying as it is influenced by ambient energy sources, said second detector means producing a second signal responsive thereto; and control means responsive to the first and second signals for controlling the operation of a wiper motor, said control means including a manually actuable adjustment device accessible to the vehicle operator for altering the response of said control means to at least one of said first and second signals, whereby the vehicle operator can adjust the sensitivity of said control assembly to various amounts of moisture on the windshield. - View Dependent Claims (6, 7)
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8. A moisture-sensor assembly comprising:
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first means for emitting a first signal indicative of the amount of moisture on a transparent media; said first means being responsive to at least one ambient variable; second means responsive to said ambient variable for emitting a reference signal indicative of how the first signal varies in response to at least said one variable; and control means for producing a control signal as a function of the first signal and reference signal, said control means including manually actuable adjustment means accessible by a human operator for changing the effect of one of the first signal and reference signal, thereby enabling the operator to adjust the sensitivity of said control means to various amounts of moisture on the transparent media. - View Dependent Claims (9, 10)
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11. A moisture sensitive control system for an automotive windshield wiper, said control system comprising:
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a wiper; motive means for driving said wiper; a first manually actuable switch accessible by the vehicle operator and having three states, an off state indicating that said wiper should not be actuated, an intermittent state indicating that said wiper should be intermittently actuated at selected time intervals, and an on state indicating that said wiper should be continuously actuated; moisture sensor means for providing a signal indicative of moisture on the vehicle windshield; a second manually actuable switch accessible by the vehicle operator and having two states, an off state indicating that wiper operation in response to said moisture sensor means is not desired and an on state indicating that said wiper should be operated in response to said moisture sensor means; and control means responsive to said first and second switches and said moisture sensor means for controlling said wiper motive means, said control means; (a) causing said motive means to remain dormant when said first switch is in the off state; (b) operating said motive means continuously when said first switch is in the on state; (c) operating said motive means intermittently at a selectable time interval when said first switch is in the intermittent state and said second switch is in the off state; and (d) operating said motive means in response to said moisture sensor means when said first switch is in the intermittent state and said second switch is in the on state. - View Dependent Claims (12)
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13. A windshield wiper system comprising:
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a wiper motive means; a first switch having three states indicating that said motive means should be turned off, operated intermittently at a time interval, or operated continuously; moisture detector means for outputting a signal indicative of moisture on the vehicle windshield; a second switch having two states indicating that said motive means should or should not be responsive to said detector means; and control means responsive to said first and second switches for controlling said motive means in response to said moisture detector means only when said first switch is in the state indicating intermittent operation and said second switch is in the state indicating that said motive means should be responsive to said detector means. - View Dependent Claims (14)
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15. A windshield wiper moisture-detection system comprising:
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emitter means for emitting electromagnetic radiation; detector means for detecting the electromagnetic radiation emitted by said emitter means and refracted and reflected by a vehicle windshield; control means responsive to said detector means for causing actuating of a vehicle windshield wiper when a preselected amount of moisture is determined to be on the windshield; second detector means for detecting ambient light; and inhibit means responsive to said second detector means for comparing the detected level of ambient light to a preselected level of ambient light and inhibiting actuation of the vehicle wiper when said detected level of ambient light exceeds said preselected level of ambient light, whereby the likelihood that the wiper will be falsely actuated by relatively high ambient light levels alone is reduced. - View Dependent Claims (16, 17)
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Specification