US6078056A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Moisture sensor with autobalance control
Assignee: Pilkington North America Inc
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Filing: 1998-12-30
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Granted: 2000-06-20
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Expires: 2018-12-30
Abstract
Abstract An autobalance control circuit for use in a moisture sensor which senses moisture on the surface of a transparent material. The moisture sensor includes detectors for receiving emitter signals which are influenced by moisture on the transparent material. The moisture sensor further includes a pre-demodulation circuit for attenuating unwanted signal components in the detector output signal while amplifying the useful signal components for further processing by a microcomputer. An autobalance circuit is provided for receiving the pre-demodulation circuit signal and providing an autobalance signal to the pre-demodulation circuit input. The autobalance signal at least partially cancels the detector output signal to prevent saturation of the pre-demodulation amplifier when undesirable detector output signal amplitudes are encountered. By preventing saturation of the moisture sensor circuitry, the autobalance circuit allows the sensor to continue to operate in the presence of large drops of moisture while having sufficient gain for detecting small droplets of moisture.
Inventors
- 👤 Rein S. Teder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:53
CPC Classifications
B; B60; B60S; B60S1/00; B60S1/02; B60S1/04; B60S1/06; B60S1/08; B60S1/0818; B60S1/0822; B60S1/0833; B60S1/0837; G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/43
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
163 words
A moisture sensor for detecting the presence of moisture on the surface of a transparent material and controlling the actuation of a moisture removal system accordingly, said moisture sensor comprising: an emitter for generating an emitter signal which is influenced by the presence of moisture on the surface of a transparent material; a detector for receiving said emitter signal and contributing to the production of a detector output signal; a pre-demodulation circuit connected to said detector and including an input for receiving said detector output signal and an output for providing a pre-demodulation signal, said pre-demodulation circuit further including a filter connected to said input for filtering unwanted signal components from said detector output signal, and an amplifier connected to said filter for providing gain to said pre-demodulation signal; and an autobalance circuit connected to said pre-demodulation circuit output for receiving said pre-demodulation signal and providing an autobalance signal to said pre-demodulation circuit input for at least partially canceling said detector output signal.
Claim 2
Dependent Claim
163 words
A moisture sensor for detecting the presence of moisture on the surface of a transparent material and controlling the actuation of a moisture removal system accordingly, said moisture sensor comprising: an emitter for generating an emitter signal which is influenced by the presence of moisture on the surface of a transparent material; a detector for receiving said emitter signal and contributing to the production of a detector output signal; a pre-demodulation circuit connected to said detector and including an input for receiving said detector output signal and an output for providing a pre-demodulation signal, said pre-demodulation circuit further including a filter connected to said input for filtering unwanted signal components from said detector output signal, and an amplifier connected to said filter for providing gain to said pre-demodulation signal; and an autobalance circuit connected to said pre-demodulation circuit output for receiving said pre-demodulation signal and providing an autobalance signal to said pre-demodulation circuit input for at least partially canceling said detector output signal.
Claim 3
Dependent Claim
33 words
The moisture sensor defined in claim 1 wherein said autobalance circuit includes an averaging circuit for receiving said pre-demodulation signal and providing an average of said pre-demodulation signal to said pre-demodulation circuit input.
Claim 4
Dependent Claim
21 words
The moisture sensor defined in claim 2 wherein said averaging circuit includes a low pass filter for averaging said pre-demodulation signal.
Claim 5
Dependent Claim
35 words
The moisture sensor defined in claim 2 wherein said emitter signals and said detector output signal are pulsatile signals, said detector output signal including a regularly repeating signal interval having a moisture sensing signal portion.
Claim 6
Dependent Claim
49 words
The moisture sensor defined in claim 4 wherein said autobalance circuit includes a first switching element connected between said averaging circuit and said pre-demodulation circuit output, whereby said first switching element is closed to pass said pre-demodulation signal during said moisture sensing signal portion of said detector output signal.
Claim 7
Dependent Claim
52 words
The moisture sensor defined in claim 5 wherein said autobalance circuit includes a second switching element connected between said averaging circuit and said pre-demodulation circuit input, whereby said second switching element is closed to pass said average of said pre-demodulation signal during said moisture sensing signal portion of said detector output signal.
Claim 8
Dependent Claim
29 words
The moisture sensor defined in claim 6 wherein said detector output signal and said autobalance signals are pulsatile current signals and said pre-demodulation signal is a pulsatile voltage signal.
Claim 9
Dependent Claim
42 words
The moisture sensor defined in claim 7 wherein said autobalance circuit includes a resistor connected between said second switching element and said pre-demodulation circuit input for providing a current signal to said pre-demodulation circuit representing the average of said pre-demodulation signal voltage.
Claim 10
Dependent Claim
168 words
An autobalance circuit for a moisture sensor, wherein said moisture sensor includes an emitter for generating an emitter signal which is influenced by the presence of moisture on the surface of a transparent material, a detector for receiving said emitter signal and contributing to the production of a detector output signal, and a pre-demodulation circuit connected to said detector and including an input for receiving said detector output signal and an output for providing a pre-demodulation signal, said pre-demodulation circuit further including a filter connected to said input for filtering unwanted signal components from said detector output signal, and an amplifier connected to said filter for providing gain to said pre-demodulation signal, said autobalance circuit comprising: an averaging circuit connected to said pre-demodulation circuit output for receiving said pre-demodulation signal and providing an autobalance signal to said pre-demodulation circuit input for at least partially cancelling said detector output signal for preventing said pre-demodulation circuit from clipping as a result of variations in amplitude of said detector output signal.
Claim 11
Dependent Claim
168 words
An autobalance circuit for a moisture sensor, wherein said moisture sensor includes an emitter for generating an emitter signal which is influenced by the presence of moisture on the surface of a transparent material, a detector for receiving said emitter signal and contributing to the production of a detector output signal, and a pre-demodulation circuit connected to said detector and including an input for receiving said detector output signal and an output for providing a pre-demodulation signal, said pre-demodulation circuit further including a filter connected to said input for filtering unwanted signal components from said detector output signal, and an amplifier connected to said filter for providing gain to said pre-demodulation signal, said autobalance circuit comprising: an averaging circuit connected to said pre-demodulation circuit output for receiving said pre-demodulation signal and providing an autobalance signal to said pre-demodulation circuit input for at least partially cancelling said detector output signal for preventing said pre-demodulation circuit from clipping as a result of variations in amplitude of said detector output signal.
Claim 12
Dependent Claim
23 words
The autobalance circuit defined in claim 9 wherein said averaging circuit provides an average of said pre-demodulation signal to said pre-demodulation circuit input.
Claim 13
Dependent Claim
21 words
The autobalance circuit defined in claim 10 wherein said averaging circuit includes a low pass filter for averaging said pre-demodulation signal.
Claim 14
Dependent Claim
36 words
The autobalance circuit defined in claim 10 wherein said emitter signals and said detector output signal are pulsatile signals, wherein said detector output signal includes a regularly repeating signal interval having a moisture sensing signal portion.
Claim 15
Dependent Claim
49 words
The autobalance circuit defined in claim 12 wherein said autobalance circuit includes a first switching element connected between said averaging circuit and said pre-demodulation circuit output, whereby said first switching element is closed to pass said pre-demodulation signal during said moisture sensing signal portion of said detector output signal.
Claim 16
Dependent Claim
52 words
The autobalance circuit defined in claim 13 wherein said autobalance circuit includes a second switching element connected between said averaging circuit and said pre-demodulation circuit input, whereby said second switching element is closed to pass said average of said pre-demodulation signal during said moisture sensing signal portion of said detector output signal.
Claim 17
Dependent Claim
29 words
The autobalance circuit defined in claim 14 wherein said detector output signal and said autobalance signals are pulsatile current signals and said pre-demodulation signal is a pulsatile voltage signal.
Claim 18
Dependent Claim
42 words
The autobalance circuit defined in claim 15 wherein said autobalance circuit includes a resistor connected between said second switching element and said pre-demodulation circuit input for providing a current signal to said pre-demodulation circuit representing the average of said pre-demodulation signal voltage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-06-20 | 2003-12-20 | 2004-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-06-20 | 2007-12-20 | 2008-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-06-20 | 2011-12-20 | 2012-06-20 | $7700.00 | Window Closed / Lapsed |