US5818043A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bolometric thermal detector
Assignee: Thales SA
•
Filing: 1997-07-21
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Granted: 1998-10-06
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Expires: 2017-07-21
Abstract
Abstract A thermal imaging detector including a layer of heat-sensitive material which includes a doped ferroelectric material exhibiting a pronounced rise in resistance with temperature in the vicinity of the ferroelectric/paraelectric transition, a multiplexing circuit, a thermally insulating thin-film microstructure, and a matrix segmentation at the level of the material of the heat-sensitive layer, so as to define heat-sensitive picture elements.
Inventors
- 👤 François Buchy
- 👤 Philippe Robin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:16
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/10; G01J5/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
156 words
Thermal imaging system comprising: a layer of heat-sensitive material which comprises a doped ferroelectric material exhibiting a pronounced rise in resistance with temperature in the vicinity of the ferroelectric/paraelectric transition, a substrate, a multiplexing circuit formed on said substrate, a thermally insulating thin-film microstructure formed on said substrate and on which said layer of heat-sensitive material is formed, a matrix segmentation at the level of the layer of heat-sensitive material, so as to define heat-sensitive picture elements coupled to said multiplexing circuit, said microstructure including plural microbridges formed of an insulating material and each microbridge supporting a respective heat-sensitive picture element and insulating said respective heat-sensitive picture element from said substrate; and a constant voltage measurement circuit which applies a constant voltage to each of said heat-sensitive picture elements and which measures a change in resistance of each of said heat-sensitive picture elements as a change in current flowing through each of said heat-sensitive picture elements.
Claim 2
Dependent Claim
156 words
Thermal imaging system comprising: a layer of heat-sensitive material which comprises a doped ferroelectric material exhibiting a pronounced rise in resistance with temperature in the vicinity of the ferroelectric/paraelectric transition, a substrate, a multiplexing circuit formed on said substrate, a thermally insulating thin-film microstructure formed on said substrate and on which said layer of heat-sensitive material is formed, a matrix segmentation at the level of the layer of heat-sensitive material, so as to define heat-sensitive picture elements coupled to said multiplexing circuit, said microstructure including plural microbridges formed of an insulating material and each microbridge supporting a respective heat-sensitive picture element and insulating said respective heat-sensitive picture element from said substrate; and a constant voltage measurement circuit which applies a constant voltage to each of said heat-sensitive picture elements and which measures a change in resistance of each of said heat-sensitive picture elements as a change in current flowing through each of said heat-sensitive picture elements.
Claim 3
Dependent Claim
16 words
Thermal imaging system according to claim 1, wherein the sensitive material is a doped ferroelectric ceramic.
Claim 4
Dependent Claim
15 words
Thermal imaging system according to claim 2, wherein the doped ferroelectric ceramic comprises barium titanate.
Claim 5
Dependent Claim
16 words
Thermal imaging system according to claim 3, wherein the doped ferroelectric ceramic further comprises strontium titanate.
Claim 6
Dependent Claim
22 words
Thermal imaging system according to claim 1, wherein the sensitive material comprises a layer of doped ferroelectric material and a semiconductor layer.
Claim 7
Dependent Claim
29 words
Thermal imaging detector according to claim 1, wherein the doping is provided by a material selected from the group consisting of antimony, yttrium, manganese, and the rare earth materials.
Claim 8
Dependent Claim
19 words
Thermal imaging system according to claim 6, wherein the percentage of dopant is between approximately 0.1% and approximately 1%.
Claim 9
Dependent Claim
14 words
Thermal imaging system according to claim 1, wherein the insulating material is silicon nitride.
Claim 10
Dependent Claim
20 words
Thermal imaging system according to claim 8, wherein said ferroelectric material of said heat sensitive picture element is a ceramic.
Claim 11
Dependent Claim
28 words
Thermal imaging system according to claim 9, further comprising planar electrodes arranged on a lower surface and on an upper surface of said respective heat sensitive picture elements.
Claim 12
Dependent Claim
27 words
Thermal imaging system according to claim 9, further comprising electrodes located on side walls of the sensitive elements and also partially covering upper faces of said elements.
References Cited (Backward Citations)
US3637532A
Cited
US3644864A
Cited
US3996168A
Cited
US4104509A
Cited
US4117328A
Cited
US4575631A
Cited
GB2152750A
Cited
US4853538A
Cited
US5122666A
Cited
US5281845A
Cited
US5297438A
Cited
WO1993009414A1
Cited
US5367282A
Cited
US5512748A
Cited
US5559332A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-10-05 | 2002-04-06 | 2002-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-10-05 | 2006-04-06 | 2006-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-10-05 | 2010-04-06 | 2010-10-06 | $7700.00 | Window Closed / Lapsed |