US4257693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cine camera
Assignee: Canon Inc
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Filing: 1979-02-08
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Granted: 1981-03-24
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Expires: 1999-02-08
Abstract
Abstract The present invention is to provide a cine camera in which the exposure time is accurately maintained by detecting the time during which the film is actually exposed and, upon occurrence of a difference of this detected value from the set value, by varying the shutter open angle to compensate the exposure time.
Inventors
- 👤 Noritsugu Hirata
- 👤 Hiroyuki Takimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:14
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083; G03B9/00; G03B9/08; G03B9/10; G03B9/12; G03B9/58
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
100 words
A cine camera comprising a rotary shutter having a plurality of shutter blades, a shutter open angle varying device, means for setting an exposure time, time signal forming means for producing a reference time signal corresponding to the time set by said exposure means, means for producing a signal corresponding to the opening and closing of the shutter, a detecting circuit receptive of said time signal and said shutter opening and closing signal for detecting the exposure time of the shutter, and driving means responsive to the output of said detecting circuit for driving said shutter open angle varying device.
Claim 2
Dependent Claim
100 words
A cine camera comprising a rotary shutter having a plurality of shutter blades, a shutter open angle varying device, means for setting an exposure time, time signal forming means for producing a reference time signal corresponding to the time set by said exposure means, means for producing a signal corresponding to the opening and closing of the shutter, a detecting circuit receptive of said time signal and said shutter opening and closing signal for detecting the exposure time of the shutter, and driving means responsive to the output of said detecting circuit for driving said shutter open angle varying device.
Claim 3
Dependent Claim
46 words
A cine camera according to claim 1, wherein said means for producing a signal corresponding to the said shutter opening and closing includes a light-emitting element and a photo-electric transducer for receiving light from said light-emitting element when the shutter blades opens the aperture for exposure.
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) | 1984-03-23 | 1984-09-22 | 1985-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-23 | 1988-09-22 | 1989-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-23 | 1992-09-22 | 1993-03-24 | $7700.00 | Window Closed / Lapsed |