US3971048A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure value display system for a camera
Assignee: Canon Inc
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Filing: 1974-09-30
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Granted: 1976-07-20
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Expires: 1994-09-30
Abstract
Abstract In a single lens reflex camera equipped with a shutter time preselection-automatic exposure range and a diaphragm aperture preselection-automatic exposure range, the drive circuits of a light-sensor and a digit readout assembly arranged in the view finder are controlled in time-spaced relation to each other by timing signals. These signals in turn are controlled by a train of clock pulses to alternately bring the sensor and the digit readout assembly into sequential operation. In this manner, the light value as sensed by the sensor is not affected by any part of the light from the energized digit readout assembly.
Inventors
- 👤 Tadashi Ito
- 👤 Soichi Nakamoto
- 👤 Youichi Okuno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:25
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/18; G03B17/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
125 words
An exposure value display system for a camera of TTL type comprising in combination: a. a finder optical system, said finder optical system being associated with an objective lens; b. sensor means arranged in said finder optical system to receive light passing through said objective lens; c. first control means for controlling the light-metering operation of said sensor means; d. display means arranged in said finder optical system to display an exposure value; e. second control means for controlling the display operation of said display means; and f. pulse generator means connected to said first and second control means for supplying output pulses which control the operation periods of said first and second control means in time-displaced relation with respect to each other in sequence.
Claim 2
Dependent Claim
125 words
An exposure value display system for a camera of TTL type comprising in combination: a. a finder optical system, said finder optical system being associated with an objective lens; b. sensor means arranged in said finder optical system to receive light passing through said objective lens; c. first control means for controlling the light-metering operation of said sensor means; d. display means arranged in said finder optical system to display an exposure value; e. second control means for controlling the display operation of said display means; and f. pulse generator means connected to said first and second control means for supplying output pulses which control the operation periods of said first and second control means in time-displaced relation with respect to each other in sequence.
Claim 3
Dependent Claim
16 words
An exposure value display system according to claim 1, wherein said sensor means includes a photodiode.
Claim 4
Dependent Claim
16 words
An exposure value display system according to claim 1, wherein said display means includes light-emitting diodes.
Claim 5
Dependent Claim
39 words
An exposure value display system according to claim 1, wherein said sensor means is connected to an exposure control means, said exposure control means deriving said exposure value in correspondence with the light value sensed by said sensor means.
Claim 6
Dependent Claim
19 words
An exposure value display system according to claim 1, wherein said pulse generator means includes a timing pulse generator.
References Cited (Backward Citations)
US3812503A
Cited
US3818495A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-20 | 1980-01-19 | 1980-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-20 | 1984-01-19 | 1984-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-20 | 1988-01-19 | 1988-07-20 | $7700.00 | Window Closed / Lapsed |