US3626827A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic exposure adjustment device for flash photography
Assignee: Minolta Co Ltd
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Filing: 1968-10-25
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Granted: 1971-12-14
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Expires: 1988-10-25
Abstract
Abstract An automatic exposure adjustment device for flash photography wherein part of the light rays of the flashbulb enter the photoelectric element and thus the flashlight intensity can be measured by the photoelectric element. The exposure adjustment factors, except the exposure time, are made to correspond with the light intensity control part, such as a filter or a stop, which controls the light intensity of the beam on the photoelectric element and also with the variable resistance which adjusts the switching starting voltage of the transistor which is operated by the electric delay circuit. The photoelectric element is the time constant factor and optimal conditions for the subject''s distance, the camera lens stop, the film sensitivity and the flash for flash photography may be automatically established and the exposure time determined.
Inventors
- 👤 Akio Yanagi
- 👤 Shoichiro Kakuta
- 👤 Takeo Iida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:30
CPC Classifications
G; G03; G03B; G03B15/00; G03B15/02; G03B15/03; G03B15/04; G03B7/00; G03B7/16
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
278 words
A control device for automatically adjusting the exposure time of a camera having a photoflash unit, a focus adjusting device and a stop adjustment mechanism comprising; an electric power source, delay means for providing a variable output proportional to the direct light emitted from said photoflash unit, said delay means including a photoconductive element responsive to said direct light and connected to said power source, a capacitor connected to said photoconductive element to be charged by the current therethrough, means for providing a first signal which varies in accordance with the distance of the subject from the camera, said means including a variable resistance connected to said power source and varied in accordance with the square of the setting of said focus adjusting device, means for providing a second signal which varies in accordance with said stop adjustment mechanism, said means including another Variable resistance connected to said power source and varied in accordance with the square of the setting of said stop adjustment mechanism, means for varying the transmission of light from said photoflash unit to said photoconductive element in accordance with the film sensitivity, said means including a light quantity adjusting device interposed between said photoconductive element and said photoflash unit, and means for operating the camera shutter in accordance with said first signal, said second signal and said variable output, said means including a switching circuit having a transistor, the base of said transistor is connected to said capacitor, the emitter of said transistor is connected to said variable resistance and said another variable resistance so that the switching of said transistor is controlled by the variation of said variable and said another variable resistance.
Claim 2
Dependent Claim
278 words
A control device for automatically adjusting the exposure time of a camera having a photoflash unit, a focus adjusting device and a stop adjustment mechanism comprising; an electric power source, delay means for providing a variable output proportional to the direct light emitted from said photoflash unit, said delay means including a photoconductive element responsive to said direct light and connected to said power source, a capacitor connected to said photoconductive element to be charged by the current therethrough, means for providing a first signal which varies in accordance with the distance of the subject from the camera, said means including a variable resistance connected to said power source and varied in accordance with the square of the setting of said focus adjusting device, means for providing a second signal which varies in accordance with said stop adjustment mechanism, said means including another Variable resistance connected to said power source and varied in accordance with the square of the setting of said stop adjustment mechanism, means for varying the transmission of light from said photoflash unit to said photoconductive element in accordance with the film sensitivity, said means including a light quantity adjusting device interposed between said photoconductive element and said photoflash unit, and means for operating the camera shutter in accordance with said first signal, said second signal and said variable output, said means including a switching circuit having a transistor, the base of said transistor is connected to said capacitor, the emitter of said transistor is connected to said variable resistance and said another variable resistance so that the switching of said transistor is controlled by the variation of said variable and said another variable resistance.
Claim 3
Dependent Claim
276 words
A control device for automatically adjusting the exposure time of a camera having a photoflash unit, a focus-adjusting device and a stop adjustment mechanism comprising: an electric power source, delay means for providing a variable output proportional to the direct light emitted from said photoflash unit, said delay means including a photoconductive element responsive to said direct light and connected to said power source, a capacitor connected to said photoconductive element to be charged by the current therethrough, means for providing a first signal which varies in accordance with the distance of the subject from the camera, said means including a variable resistance connected to said power source and varied in accordance with the square of the setting of said focus adjusting device, means for providing a second signal which varies in accordance with the square of the film sensitivity, said means including another variable resistance varied in accordance with the square of the film sensitivity, means for varying the transmission of light from said photoflash unit to said photoconductive element in accordance with the square of the setting of said stop adjustment mechanism, said means including a light quantity adjusting device interposed between said photoconductive element and said photoflash unit, and means for operating the camera shutter in accordance with said first signal, said second signal and said variable output, said means including a switching circuit having a transistor, the base of said transistor is connected to said capacitor, the emitter of said transistor is connected to said variable resistance and said another variable resistance so that the switching of said transistor is controlled by the variation of said variable and said another variable resistance.
Claim 4
Dependent Claim
276 words
A control device for automatically adjusting the exposure time of a camera having a photoflash unit, a focus-adjusting device and a stop adjustment mechanism comprising: an electric power source, delay means for providing a variable output proportional to the direct light emitted from said photoflash unit, said delay means including a photoconductive element responsive to said direct light and connected to said power source, a capacitor connected to said photoconductive element to be charged by the current therethrough, means for providing a first signal which varies in accordance with the distance of the subject from the camera, said means including a variable resistance connected to said power source and varied in accordance with the square of the setting of said focus adjusting device, means for providing a second signal which varies in accordance with the square of the film sensitivity, said means including another variable resistance varied in accordance with the square of the film sensitivity, means for varying the transmission of light from said photoflash unit to said photoconductive element in accordance with the square of the setting of said stop adjustment mechanism, said means including a light quantity adjusting device interposed between said photoconductive element and said photoflash unit, and means for operating the camera shutter in accordance with said first signal, said second signal and said variable output, said means including a switching circuit having a transistor, the base of said transistor is connected to said capacitor, the emitter of said transistor is connected to said variable resistance and said another variable resistance so that the switching of said transistor is controlled by the variation of said variable and said another variable resistance.
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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) | 1974-12-13 | 1975-06-14 | 1975-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-13 | 1979-06-14 | 1979-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-13 | 1983-06-14 | 1983-12-14 | $7700.00 | Window Closed / Lapsed |