Rain detector
First Claim
1. An improved rain detector which includes a sensor for a windshield, the sensor emitting a signal having a level, and first means for comparing the level of the signal emitted by the sensor with a threshold, with the first means emitting a switching signal to a windshield wiper unit based on a result of the comparison of the level of the signal and the threshold, wherein the improvement comprises:
- a second means for comparing the level of the signal emitted by the sensor which corresponds to a clean windshield with a reference signal, and for adjusting the signal emitted by the sensor to a predetermined resting level.
1 Assignment
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Accused Products
Abstract
A rain detector in which the level of a sensor signal (15) which is emitted by a sensor (14) or the level of a sensor signal (17) which is processed by a signal processing unit (16) is set at a predetermined resting level (44) by a control unit (19, 30). This use of a predetermined reference level makes possible an automatic calibration of the rain detector which takes into consideration all tolerances for electrical and optical components, their age-related drift, and tolerances during the installation of the rain detector.
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Citations
19 Claims
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1. An improved rain detector which includes a sensor for a windshield, the sensor emitting a signal having a level, and first means for comparing the level of the signal emitted by the sensor with a threshold, with the first means emitting a switching signal to a windshield wiper unit based on a result of the comparison of the level of the signal and the threshold, wherein the improvement comprises:
- a second means for comparing the level of the signal emitted by the sensor which corresponds to a clean windshield with a reference signal, and for adjusting the signal emitted by the sensor to a predetermined resting level.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A rain detector for use with a vehicle having a windshield and a windshield wiper unit, comprising:
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first means for emitting a first signal to the windshield; second means, including a sensor for sensing the first signal, for generating a second signal which provides information about how the state of the windshield has influenced the first signal, the second signal being based on the first signal sensed by the sensor; third means for adjusting the second signal so that the second signal has a predetermined resting value when the information provided by the second signal indicates that the windshield is in a predetermined state; and fourth means for comparing the second signal and a threshold signal to generate a switching signal for the windshield wiper unit. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification