US3797941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoelectric exposure control device
Assignee: Agfa Gevaert NV
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Filing: 1972-01-18
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Granted: 1974-03-19
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Expires: 1992-01-18
Abstract
Abstract A method and apparatus for photographically recording colour subjects onto recording material which is spectrally sensitive in different regions of the visible light spectrum. The luminance of the colour subject is measured in at least two of the different regions wherein the recording material is sensitive, the exposure of the recording material is predetermined in taking the measured luminance of the subject in the region of greatest luminance more into acount than the measured luminance(s) of the region(s) of smaller luminance, and the recording material is exposed to the colour subject to an extent which is in accordance with said predetermined exposure.
Inventors
- 👤 K Staes
- 👤 L Natens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:57
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/42
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
181 words
A photoelectric exposure control device for determining the extent of the photographic exposure to a multicolored subject of a recording material which is spectrally sensitive to at least two different regions of the visible light spectrum, comprising: a. photoelectric cell means for separately measuring the luminance of the colored subject in said at least two different regions wherein the recording material is sensitive and furnishing separate output signals according to such measurements, said photoelectric cell means being arranged for measuring said luminances in substantially the same image area of said subject, b. discrete amplification means for amplifying the corresponding output signals of said photoelectric cell means, and an interconnection circuit for interconnecting the outputs of said discrete amplification means so that the amplified output signal corresponding to the region of the greatest luminance of such regions is selected from said amplifier output signals, and c. means responsive to said interconnection circuit for indicating the extent of photographic exposure for said recording material in all such spectral regions, said eXtent generally corresponding to the amplified output signal selected by said interconnection circuit.
Claim 2
Dependent Claim
181 words
A photoelectric exposure control device for determining the extent of the photographic exposure to a multicolored subject of a recording material which is spectrally sensitive to at least two different regions of the visible light spectrum, comprising: a. photoelectric cell means for separately measuring the luminance of the colored subject in said at least two different regions wherein the recording material is sensitive and furnishing separate output signals according to such measurements, said photoelectric cell means being arranged for measuring said luminances in substantially the same image area of said subject, b. discrete amplification means for amplifying the corresponding output signals of said photoelectric cell means, and an interconnection circuit for interconnecting the outputs of said discrete amplification means so that the amplified output signal corresponding to the region of the greatest luminance of such regions is selected from said amplifier output signals, and c. means responsive to said interconnection circuit for indicating the extent of photographic exposure for said recording material in all such spectral regions, said eXtent generally corresponding to the amplified output signal selected by said interconnection circuit.
Claim 3
Dependent Claim
35 words
A photoelectric exposure control device according to claim 1 including, in addition to said interconnection circuit for interconnecting the outputs of said discrete amplification means, electrical resistance through which the discrete amplification means are interconnected.
Claim 4
Dependent Claim
36 words
A photoelectric exposure control device according to claim 1 comprising three photoelectric cell means for measuring the luminances of the subject in the blue, the green, and the red regions respectively, of the visible light spectrum.
Claim 5
Dependent Claim
24 words
A photoelectric exposure control device according to claim 1 comprising a further amplification means for amplifying the output signal selected by said interconnection circuit.
Claim 6
Dependent Claim
53 words
A photoelectric exposure control device according to claim 1 wherein said means for comparing and selecting are formed by three diodes which are connected with the same electrode each to the output of the mentioned three amplifiers, and which are connected with the other electrodes together to the input of said further amplifier.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |