US3772974A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single-lens reflex camera with an automatic aperture control device
Assignee: Nikon Corp
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Filing: 1972-08-22
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Granted: 1973-11-20
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Expires: 1992-08-22
Abstract
Abstract A single-lens reflex camera with an automatic aperture control device comprises a photoelectric element for converting the intensity of light from an object through an objective lens into an electrical signal and disposed so that the light passed thereto through the lens may be intercepted during film exposure. Synchro contacts for flash photography are provided and adapted to close upon shutter release, and aperture control means is provided for varying the aperture opening of the objective lens. A motor for operating the aperture control means is connected with a circuit including the photoelectric element to control the aperture control means in accordance with the electrical signal. Means for stopping the motor is connected with the circuit to cut off a current to the motor upon closing of the synchro contacts, thereby stopping the motor.
Inventors
- 👤 J Shimomura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:50
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/085
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
198 words
An automatic aperture control device for a single-lens reflex camera, comprising: photoelectric conversion means (T1, T2, R1, R2, Rv, Rc) for converting into an electrical signal the intensity of light passed from an object through an objective lens, said photoelectric conversion means including a photoelectric element disposed so that the light passed thereto through said objective lens may be reduced after actuation of a shutter control, driving means (M, 33, 34, 35) for adjusting the size of diaphragm aperture of said objective lens, said driving means being connected to said aperture control means and including one motor, controlling means (T3, T4, R3, R4, T5, T6, 31d, 31c) for controlling said driving means, said controlling means including a first controlling means (T3, T4, R3, R4, T5, T6) for controlling said driving means in response to said electric signal from said photoelectric conversion means and second controlling means (31d, 31c) for stopping said driving means, and synchro contact means for flash photography adapted to be closed at the latest when the shutter of the camera is fully opened, said synchro contact means being connected to said stopping means to stop said driving means after the synchro contact means is closed.
Claim 2
Dependent Claim
198 words
An automatic aperture control device for a single-lens reflex camera, comprising: photoelectric conversion means (T1, T2, R1, R2, Rv, Rc) for converting into an electrical signal the intensity of light passed from an object through an objective lens, said photoelectric conversion means including a photoelectric element disposed so that the light passed thereto through said objective lens may be reduced after actuation of a shutter control, driving means (M, 33, 34, 35) for adjusting the size of diaphragm aperture of said objective lens, said driving means being connected to said aperture control means and including one motor, controlling means (T3, T4, R3, R4, T5, T6, 31d, 31c) for controlling said driving means, said controlling means including a first controlling means (T3, T4, R3, R4, T5, T6) for controlling said driving means in response to said electric signal from said photoelectric conversion means and second controlling means (31d, 31c) for stopping said driving means, and synchro contact means for flash photography adapted to be closed at the latest when the shutter of the camera is fully opened, said synchro contact means being connected to said stopping means to stop said driving means after the synchro contact means is closed.
Claim 3
Dependent Claim
115 words
An automatic aperture control device according to claim 1, wherein said photoelectric conversion means generates a first electric signal in a case of under-exposure and a second electric signal in a case of over-exposure; said second controlling means includes first means (T4, T6) adapted to be actuated by said first signal so that the size of the diaphragm aperture may be enlarged, and second means (T3, T5) adapted to be actuated by said second signal so that the size of the diaphragm aperture may be reduced, said first means being connected to said synchro contact means through said second controlling means so that the closure of said synchro contact means renders said first means non-operative.
Claim 4
Dependent Claim
55 words
An automatic aperture control device according to claim 2, wherein said first means include a transistor the base and emitter terminals of which are connected to said second controlling means, said transistor being conductive when said controlling means is actuated, and nonconductive when said synchro contact means is closed wherefor said driving means is stopped.
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) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |