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US4107708A
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US
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Shutter control circuit having exposure time display
Assignee: Seiko Koki KK
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Filing: 1976-06-21
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Granted: 1978-08-15
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Expires: 1996-06-21
Abstract
Abstract An electric shutter circuit having an exposure time display disabled in synchronism with the opening of a camera shutter. A brightness-time conversion circuit and a pulse generator together develops a plurality of pulses the number of which is representative of the exposure time and which are stored in a reversible counter. Upon actuation of a shutter release mechanism a display circuit is enabled to display the exposure time by displaying a visual signal determined by the number of pulses stored in the reversible counter. The display circuit is disabled in synchronism with the shutter opening. In one embodiment a Schmidt trigger circuit is triggered by the shutter release mechanism to disable the display circuit.
Inventors
- 👤 Takeo Saito
- 👤 Youichi Seki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:08
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/18; G03B17/20; G03B7/00; G03B7/08; G03B7/091; G03B7/093; G03B9/00; G03B9/58
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
137 words
A shutter control circuit of the type having means for developing a plurality of pulses the number of which is representative of an exposure time; means for counting and storing said plurality of pulses and for reading-out the number of stored pulses in response to command signals, for controlling an exposure time; and means for applying a command signal to said means for counting and for reading-out to initiate reading-out of the stored pulses; wherein the improvement comprises: a display circuit, cooperative with said means for counting and storing, for visually displaying the exposure time represented by the number of pulses counted and stored; said display circuit comprising means, responsive to the command signal for initiating reading-out of the stored pulses, for disabling said display circuit thereby to reduce power consumption by said display circuit during exposure.
Claim 2
Dependent Claim
137 words
A shutter control circuit of the type having means for developing a plurality of pulses the number of which is representative of an exposure time; means for counting and storing said plurality of pulses and for reading-out the number of stored pulses in response to command signals, for controlling an exposure time; and means for applying a command signal to said means for counting and for reading-out to initiate reading-out of the stored pulses; wherein the improvement comprises: a display circuit, cooperative with said means for counting and storing, for visually displaying the exposure time represented by the number of pulses counted and stored; said display circuit comprising means, responsive to the command signal for initiating reading-out of the stored pulses, for disabling said display circuit thereby to reduce power consumption by said display circuit during exposure.
Claim 3
Dependent Claim
140 words
A shutter control circuit according to claim 1, wherein said display circuit is comprised of: a plurality of logic gates cooperative with said means for counting and storing to develop a plurality of output signals each representative of a different exposure time; a plurality of AND gates each receptive of and enabled by a respective one of the logic gate output signals representative of exposure time, and each receptive of and disabled by the command signal; and a plurality of display elements each energized by a respective one of said AND gates; whereby generation of one of the plurality of logic gate output signals is effective to enable a respective display element to display the exposure time represented by the logic gate output signal, and whereby generation of the command signal is effective to de-energize all of the display elements.
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) | 1981-08-14 | 1982-02-13 | 1982-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-08-14 | 1986-02-13 | 1986-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-08-14 | 1990-02-13 | 1990-08-15 | $7700.00 | Window Closed / Lapsed |