US3868704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system for a single lens reflex camera
Assignee: Minolta Co Ltd
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Filing: 1972-08-28
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Granted: 1975-02-25
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Expires: 1992-08-28
Abstract
Abstract Digital data relating to the scene illumination is stored in a storage circuit and optionally together with digital film sensitivity and/or diaphragm aperture data. The data storing is performed by counting pulses supplied from a time base unit through a control circuit, which is selectively connected, depending on the film sensitivity and/or the diaphragm aperture data, to a first output terminal of the time base unit generating a basic pulse frequency and submultiple pulse frequencies thereof, and which has a gate circuit responsive to a light detecting circuit including a photosensitive element. Another series of pulses from a second output terminal of the time base unit selected in accordance with the exposure multiple are counted by a pulse counter up to a number corresponding to the number of pulses in the storage circuit to generate a signal for releasing the shutter.
Inventors
- 👤 Seiji Yamada
- 👤 Kotaro Yata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:31
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/091; G03B7/093
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
385 words
An exposure control system for a single lens reflex camera having a shutter mechanism comprising: a time base unit for generating a plurality of pulse trains at respective submultiple frequencies of a basic frequency and having a plurality of first output terminals for respectively providing a pulse train at said basic frequency and each of said submultiple frequencies; a detecting circuit for generating an electrical signal in response to operation of a shutter release member with a delay determined in accordance with scene light; a first switching means for selecting one of said first output terminals; a second switching means for selecting one of said first output terminals; a storage circuit for storing pulses from said output terminal selected by said first switching means, said storage circuit including a plurality of first flip-flop circuits connected in series said storage circuit having an input terminal, and a plurality of second and third output terminals each respectively connected to corresponding outputs of each of said first flip-flop circuits; a pulse counter circuit for counting pulses from said output terminal selected by said second switching means; a control circuit including a gate circuit closed in response to the operation of a shutter release member for initiating storage of pulses within said storage circuit and opened in response to said electrical signal for terminating storage of said pulses and means for initiating operation of said pulse counter in conjunction with opening of the shutter mechanism for initiating an exposure; means for generating a signal to close the shutter mechanism to terminate exposure in response to the coincidence between the number of pulses in said storage circuit and said pulse counter circuit; means for manually setting the exposure time; a third switching means for selecting one of said second output terminals in conjunction with the operation of said means for manually setting the exposure; and a feedback circuit connected between said third switching means and said gate circuit for feeding the change of output from said manually selected second output terminal connected to the output of a corresponding one of said first flip-flop circuits to said gate circuit to open said gate circuit for terminating said storage of pulses within said storage circuit when the change of the output of said corresponding flip-flop occurs because of said storage of pulses.
Claim 2
Dependent Claim
385 words
An exposure control system for a single lens reflex camera having a shutter mechanism comprising: a time base unit for generating a plurality of pulse trains at respective submultiple frequencies of a basic frequency and having a plurality of first output terminals for respectively providing a pulse train at said basic frequency and each of said submultiple frequencies; a detecting circuit for generating an electrical signal in response to operation of a shutter release member with a delay determined in accordance with scene light; a first switching means for selecting one of said first output terminals; a second switching means for selecting one of said first output terminals; a storage circuit for storing pulses from said output terminal selected by said first switching means, said storage circuit including a plurality of first flip-flop circuits connected in series said storage circuit having an input terminal, and a plurality of second and third output terminals each respectively connected to corresponding outputs of each of said first flip-flop circuits; a pulse counter circuit for counting pulses from said output terminal selected by said second switching means; a control circuit including a gate circuit closed in response to the operation of a shutter release member for initiating storage of pulses within said storage circuit and opened in response to said electrical signal for terminating storage of said pulses and means for initiating operation of said pulse counter in conjunction with opening of the shutter mechanism for initiating an exposure; means for generating a signal to close the shutter mechanism to terminate exposure in response to the coincidence between the number of pulses in said storage circuit and said pulse counter circuit; means for manually setting the exposure time; a third switching means for selecting one of said second output terminals in conjunction with the operation of said means for manually setting the exposure; and a feedback circuit connected between said third switching means and said gate circuit for feeding the change of output from said manually selected second output terminal connected to the output of a corresponding one of said first flip-flop circuits to said gate circuit to open said gate circuit for terminating said storage of pulses within said storage circuit when the change of the output of said corresponding flip-flop occurs because of said storage of pulses.
Claim 3
Dependent Claim
37 words
An exposure control system as in claim 1 further comprising a fourth switching means for preventing said detecting circuit from opening said gate circuit in conjunction with the operation of said means for manually setting the exposure.
Claim 4
Dependent Claim
22 words
An exposure control system as in claim 2 wherein said fourth switching means prevents said detecting circuit from generating said electrical signal.
Claim 5
Dependent Claim
173 words
An exposure control system as in claim 1 wherein said pulse counter circuit comprises a plurality of second flip-flop circuits connected in series, said pulse counter circuit having an input terminal, said second flip-flop circuits being equal in number to said first flip-flop circuits, each of said second flip-flop circuits having fourth and fifth output terminals; and wherein said means for generating a signal includes a pluralIty of first AND circuits respectively connected at their respective input terminals to said second output terminals and to said fourth output terminals, a plurality of second AND circuits respectively connected at their respective input terminals to said third output terminals and to said fifth output terminals, a plurality of OR circuits respectively connected with the outputs of a respective one of said first and second AND circuits connected to said second, third, fourth and fifth output terminals of a corresponding one of said first and second flip-flop circuits, and a third AND circuit having input terminals connected with the output from said plurality of OR circuits.
Claim 6
Dependent Claim
123 words
An exposure control system as in claim 1 further comprising an indicator circuit including a plurality of fourth AND circuits each connected at one input terminal thereof to successive ones of said second output terminals and at the other input terminal thereof to said successive ones of said third output terminals, a plurality of fifth AND circuits each connected at one input terminal thereof to the output terminal of a corresponding one of said fourth AND circuits and at the other input terminal to successive ones of said third output terminals, a plurality of indicating means respectively connected to the output terminals of said fifth AND circuits whereby the exposure time is indicated in accordance with the pulses stored in said storage circuit.
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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) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |