US4087687A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature control device
Assignee: United States Department of the Army
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Filing: 1977-01-28
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Granted: 1978-05-02
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Expires: 1997-01-28
Abstract
Abstract The invention is a temperature stabilizing device employing a liquid crys wherein the crystal is itself stabilized to provide a thermal viewing element.
Inventors
- 👤 Gerald T. Bean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:30
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/132; G01; G01K; G01K11/00; G01K11/12; G01K11/16; G01K11/165; G05; G05D; G05D23/00; G05D23/19; G05D23/27
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
178 words
A thermal viewing system comprising: a layer of liquid crystal having first and second mutually exclusive portions which reflect a characteristic color of light for each of a plurality of temperature increments within a given temperature range; a heat sink; a heat transfer plate attached to said layer; a reversible heat transfer means connected between said sink and said plate to change the temperature of said plate in response to an input electrical signal; infrared focussing means coupled with said layer to project an infrared image only on said first portion thereof; a source of visible light coupled with and illuminating said first portion and said second portion whereby said infrared image is rendered visible when said transfer plate is maintained at fixed temperature within said given temperature range; and a first optical detector means electrically coupled to said heat transfer means to detect color changes only in said second portion of said crystal layer and to generate said electrical input signal in inverse proportion thereto whereby equal and opposite temperature changes are induced in said transfer plate.
Claim 2
Dependent Claim
178 words
A thermal viewing system comprising: a layer of liquid crystal having first and second mutually exclusive portions which reflect a characteristic color of light for each of a plurality of temperature increments within a given temperature range; a heat sink; a heat transfer plate attached to said layer; a reversible heat transfer means connected between said sink and said plate to change the temperature of said plate in response to an input electrical signal; infrared focussing means coupled with said layer to project an infrared image only on said first portion thereof; a source of visible light coupled with and illuminating said first portion and said second portion whereby said infrared image is rendered visible when said transfer plate is maintained at fixed temperature within said given temperature range; and a first optical detector means electrically coupled to said heat transfer means to detect color changes only in said second portion of said crystal layer and to generate said electrical input signal in inverse proportion thereto whereby equal and opposite temperature changes are induced in said transfer plate.
Claim 3
Dependent Claim
33 words
A thermal viewer according to claim 1 wherein said source of visible light comprises: a first light source illuminating said first portion only; and a second light source illuminating said second portion only.
Claim 4
Dependent Claim
49 words
A thermal viewer according to claim 1 further comprising: monitor circuit means coupled with said crystal layer to detect and compare changes in temperature of said first portion with the small oscillations produced by said heat transfer means and to operate an alarm when comparatively large changes are detected.
Claim 5
Dependent Claim
35 words
A thermal viewer according to claim 3 wherein: said monitor is electrically connected between said first optical detector and said heat transfer means to detect temperature changes as a function of said input electrical signal.
Claim 6
Dependent Claim
57 words
A thermal viewer according to claim 4 wherein: said monitor means includes a second optical detector coupled to said first portion of said crystal layer, said second detector being sensitive only to a specific range of colored light reflected by said layer said range lying outside the normal range of oscillations produced by said heat transfer means.
Claim 7
Dependent Claim
30 words
A thermal viewer according to claim 5 wherein: said second optical detector is coupled to said crystal layer to receive light from a smaller portion only of said first portion.
Claim 8
Dependent Claim
40 words
A thermal viewer according to claim 6 wherein: said monitor means includes a plurality of said additional detectors, each additional detector coupled to the light reflected from a different smaller portion only of said first portion of said crystal layer.
Claim 9
Dependent Claim
41 words
A thermal viewer according to claim 6 wherein: said monitor means includes a plurality of additional detectors coupled to the light reflected from a same smaller portion of said first portion, each additional detector being sensitive to different color of light.
Claim 10
Independent Claim
77 words
The method of operating an infrared viewer wherein a liquid crystal layer is mounted on a plate which maintained at constant temperature while an infrared image and a uniform flux of visible light are projected on said layer simultaneously comprising the steps of: detecting the color of light samples reflected by said crystal over an area independent of said infrared image; and adjusting the temperature of said plate to keep the color of said samples substantially constant.
Claim 11
Independent Claim
77 words
The method of operating an infrared viewer wherein a liquid crystal layer is mounted on a plate which maintained at constant temperature while an infrared image and a uniform flux of visible light are projected on said layer simultaneously comprising the steps of: detecting the color of light samples reflected by said crystal over an area independent of said infrared image; and adjusting the temperature of said plate to keep the color of said samples substantially constant.
References Cited (Backward Citations)
US3770961A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-01 | 1981-10-31 | 1982-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-01 | 1985-10-31 | 1986-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-01 | 1989-10-31 | 1990-05-02 | $7700.00 | Window Closed / Lapsed |