US4158136A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camera system employing pyroelectric effect
Assignee: Thales SA
•
Filing: 1977-10-05
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Granted: 1979-06-12
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Expires: 1997-10-05
Abstract
Abstract A camera system, in particular for the detection of infrared radiation, wherein the detector uses the pyroelectric effect. It permits the viewing of fixed object owing to a time modulation of the radiation coming from such objects. This modulation is achieved by means of a partly transparent grid which moves between the object and the radiation detector.
Inventors
- 👤 Pierre Felix
- 👤 Lucien Guyot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:24
CPC Classifications
H; H01; H01J; H01J31/00; H01J31/08; H01J31/49; H04; H04N; H04N23/00; H04N23/20; H04N23/23
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
74 words
A camera system comprising: a detector of an incident radiation from an object to be viewed, said detector being constituted by a pyroelectric material on which the incident radiation produces a spatial distribution of electric potential representing it; means for scanning said potential distribution; a partly transparent grid which moves between said object and said detector, along an axis perpendicular to said incident radiation, and produces a time continuous modulation of said incident radiation.
Claim 2
Dependent Claim
74 words
A camera system comprising: a detector of an incident radiation from an object to be viewed, said detector being constituted by a pyroelectric material on which the incident radiation produces a spatial distribution of electric potential representing it; means for scanning said potential distribution; a partly transparent grid which moves between said object and said detector, along an axis perpendicular to said incident radiation, and produces a time continuous modulation of said incident radiation.
Claim 3
Dependent Claim
24 words
A system as claimed in claim 1, wherein the grid is moved in a plane substantially perpendicular to said incident radiation at uniform speed.
Claim 4
Dependent Claim
40 words
A system as claimed in claim 1, wherein the spatial frequency of the grid is substantially equal to the maximum spatial frequency of said object to be transmitted, said two frequencies being with respect to the region of the detector.
Claim 5
Dependent Claim
72 words
A system as claimed in claim 3, wherein said scanning means effect a scanning of said detector in lines parallel to the direction of movement of said grid, and said system further comprises means for electrically processing the signal furnished by said detector, comprising a multiplier which multiplies said signal by a sinusoidal auxiliary signal, the phase of which varies with each one of said lines and which comprises an adjustable part.
Claim 6
Dependent Claim
55 words
A system as claimed in claim 4, wherein said auxiliary signal has a frequency which is controlled in such manner that the continuous component of the product of said signal by a second auxiliary signal, furnished by at least a part of the detector illuminated uniformly through said grid, is set to a reference value.
Claim 7
Dependent Claim
41 words
A system as claimed in claim 1, wherein the spatial frequency of the grid is small with respect to the smallest spatial frequency of said object to be transmitted, said two frequencies being with respect to the region of the detector.
Claim 8
Dependent Claim
34 words
A system as claimed in claim 1, wherein said grid comprises a material absorbing said incident radiation, and in which apertures are formed so that the transparency of said grid is equal to 1/2.
Claim 9
Dependent Claim
20 words
A system as claimed in claim 1, wherein said grid is consituted by a material which diffuses said incident radiation.
Claim 10
Dependent Claim
24 words
A system as claimed in claim 1, wherein said grid is constituted by a material which changes the optical path of said incident radiation.
Claim 11
Dependent Claim
19 words
A system as claimed in claim 1, wherein said grid is positioned in the immediate vicinity of said object.
Claim 12
Dependent Claim
26 words
A system as claimed in claim 10, wherein a sinusoidal grid approximation is obtained by moving away said grid from the immediate vicinity of said object.
Claim 13
Dependent Claim
19 words
A system as claimed in claim 1, wherein said grid is placed in the immediate vicinity of said detector.
Claim 14
Dependent Claim
26 words
A system as claimed in claim 12, wherein a sinusoidal grid approximation is obtained by moving away said grid from the immediate vicinity of said detector.
Claim 15
Dependent Claim
31 words
A system as claimed in claim 1, further comprising optical means which form an intermediate image of said object in an intermediate plane, said grid being positioned in said intermediate plane.
Claim 16
Dependent Claim
23 words
A system as claimed in claim 14, wherein a sinusoidal grid approximation is obtained by moving away said grid from said intermediate plane.
References Cited (Backward Citations)
US3291991A
Cited
US3774043A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-06-11 | 1982-12-11 | 1983-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-11 | 1986-12-11 | 1987-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-11 | 1990-12-11 | 1991-06-12 | $7700.00 | Window Closed / Lapsed |