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US4734585A
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Passive infra-red sensor
Assignee: KGS Fire & Security UK Ltd
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Filing: 1986-07-16
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Granted: 1988-03-29
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Expires: 2006-07-16
Abstract
Abstract A passive infra-red sensor includes a window in a housing which also houses an infra-red detector. The window defines a plurality of infra-red transmitting strips which are separated by Fresnel lens segments or infra-red opaque strips. The infra-red transmitting strips provide short range sensitivity. The Fresnel lens segments where provided give longer range sensitivity.
Inventors
- 👤 Ian A. Owers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:17
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/189; G08B13/19; Y; Y10; Y10S; Y10S250/00; Y10S250/01
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
55 words
A passive infra-red sensor including a housing a window defined in said housing, and an infra-red detector mounted within said housing behind said window, said window defining an alternating sequence of infra-red transmitting strips which allow infra-red radiation to pass unfocused onto the detector, and lens segments positioned for focusing infra-red radiation onto said detector.
Claim 2
Dependent Claim
55 words
A passive infra-red sensor including a housing a window defined in said housing, and an infra-red detector mounted within said housing behind said window, said window defining an alternating sequence of infra-red transmitting strips which allow infra-red radiation to pass unfocused onto the detector, and lens segments positioned for focusing infra-red radiation onto said detector.
Claim 3
Dependent Claim
22 words
A sensor according to claim 1, in which the housing defines slots which provide continuations of at least some of said strips.
Claim 4
Dependent Claim
32 words
A sensor according to claim 2, in which at least some of said slots extend into a portion of the housing which faces downwardly when the sensor is in a mounted position.
Claim 5
Dependent Claim
15 words
A sensor according to claim 1, in which the lens segments are Fresnel lens segments.
Claim 6
Dependent Claim
15 words
A sensor according to claim 1, in which said window is bowed in transverse cross-section.
Claim 7
Dependent Claim
32 words
A sensor according to claim 1, in which said window further defines at least one row of adjacent Fresnel lens segments above said alternating sequence of infra-red transmitting strips and lens segments.
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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) | 1991-03-29 | 1991-09-28 | 1992-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-29 | 1995-09-28 | 1996-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-29 | 1999-09-28 | 2000-03-29 | $7700.00 | Window Closed / Lapsed |