US4096496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure control circuit for camera
Assignee: Fujinon Corp
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Filing: 1977-05-24
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Granted: 1978-06-20
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Expires: 1997-05-24
Abstract
Abstract In an exposure control circuit for a camera including a digital control circuit, a crystal oscillator is used as a pulse generator. Between the crystal oscillator and the power source is connected a small current supply circuit for constantly supplying a small current to the crystal oscillator for constantly maintaining the oscillator in a stable condition.
Inventors
- 👤 Saburo Numata
- 👤 Shinichiro Okazaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:32
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/091
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
An exposure control circuit for a camera comprising a power source, a crystal oscillator having an input and an output, a small current supply circuit connected between said power source and the input of said crystal oscillator for constantly supplying a small current to the crystal oscillator, a digital control circuit connected with the output of said crystal oscillator for controlling an exposure factor, a normally opened switch connected between the power source and the digital control circuit and also between the power source and the input of the crystal oscillator, said normally open switch being closed upon the first stage of depression of a shutter release button of the camera.
Claim 2
Dependent Claim
111 words
An exposure control circuit for a camera comprising a power source, a crystal oscillator having an input and an output, a small current supply circuit connected between said power source and the input of said crystal oscillator for constantly supplying a small current to the crystal oscillator, a digital control circuit connected with the output of said crystal oscillator for controlling an exposure factor, a normally opened switch connected between the power source and the digital control circuit and also between the power source and the input of the crystal oscillator, said normally open switch being closed upon the first stage of depression of a shutter release button of the camera.
Claim 3
Dependent Claim
29 words
An exposure control circuit for a camera as defined in claim 1 wherein a constant voltage circuit is connected between said normally open switch and said digital control circuit.
Claim 4
Dependent Claim
28 words
An exposure control circuit for a camera as defined in claim 2 wherein said constant voltage circuit is connected between said normally open switch and said crystal oscillator.
Claim 5
Dependent Claim
28 words
An exposure control circuit for a camera as defined in claim 1 wherein a constant voltage circuit is connected between said normally open switch and said crystal oscillator.
Claim 6
Dependent Claim
22 words
An exposure control circuit for a camera as defined in claim 1 wherein said small current supply circuit is a constant-current circuit.
Claim 7
Dependent Claim
20 words
An exposure control circuit for a camera as defined in claim 5 wherein said constant-current circuit comprises a constant-current diode.
Claim 8
Dependent Claim
21 words
An exposure control circuit for a camera as defined in claim 5 wherein said constant-current circuit comprises a field effect transistor.
Claim 9
Dependent Claim
23 words
An exposure control circuit for a camera as defined in claim 1 wherein said small current supply circuit is a series of diodes.
Claim 10
Dependent Claim
22 words
An exposure control circuit for a camera as defined in claim 1 wherein said small current supply circuit is a high resistor.
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) | 1981-06-19 | 1981-12-19 | 1982-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-19 | 1985-12-19 | 1986-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-19 | 1989-12-19 | 1990-06-20 | $7700.00 | Window Closed / Lapsed |