Patent US3949412A successfully refreshed from Google Patents.
US3949412A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camera with an exposure indicating and control device
Assignee: Canon Inc
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Filing: 1974-12-04
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Granted: 1976-04-06
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Expires: 1994-12-04
Abstract
Abstract A camera is provided, in which the light sensitive element for the electronic exposure meter can be commonly used as the light sensitive element for the exposure control circuit.
Inventors
- 👤 Tetsuya Taguchi
- 👤 Mutsunobu Yazaki
- 👤 Noriaki Sanada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:52
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
117 words
A camera including an exposure control apparatus having a light sensitive means for generating a control signal comprising, in combination, a first transistor connected to said light sensitive means for compressing the output signal of said light sensitive means by means of a diode connection, said first transistor having a base electrode; a regenerating circuit comprising a second transistor with a base electrode connected with the base electrode of said first transistor for enlarging the output signal of said first transistor, said second transistor including an output terminal; and an indicating means connected to the output terminal of said second transistor and operable to indicate the exposure quantity in accordance with the output of said second transistor.
Claim 2
Dependent Claim
117 words
A camera including an exposure control apparatus having a light sensitive means for generating a control signal comprising, in combination, a first transistor connected to said light sensitive means for compressing the output signal of said light sensitive means by means of a diode connection, said first transistor having a base electrode; a regenerating circuit comprising a second transistor with a base electrode connected with the base electrode of said first transistor for enlarging the output signal of said first transistor, said second transistor including an output terminal; and an indicating means connected to the output terminal of said second transistor and operable to indicate the exposure quantity in accordance with the output of said second transistor.
Claim 3
Dependent Claim
14 words
A camera according to claim 1, wherein said first transistor is a pnp-type transistor.
Claim 4
Dependent Claim
14 words
A camera according to claim 1, wherein said second transistor is a pnp-type transistor.
Claim 5
Dependent Claim
32 words
A camera according to claim 1, wherein said regenerating circuit comprises a bleeder resistor connected with said output terminal of said second transistor for applying the input voltage to said indicating means.
Claim 6
Dependent Claim
13 words
A camera according to claim 4, wherein said resistor is a variable resistor.
Claim 7
Dependent Claim
23 words
A camera according to claim 1, wherein said indicating means comprises a detecting means for detecting the output voltage of said regenerating circuit.
Claim 8
Dependent Claim
34 words
A camera according to claim 6, wherein said indicating means further comprises a luminous diode connected to the output terminal of said detecting means for indicating whether or not the exposure quantity is sufficient.
Claim 9
Dependent Claim
178 words
A camera including an exposure control apparatus having a light sensitive means for generating a control signal comprising, in combination, a first transistor connected to said light sensitive means and operable to compress the output signal of said light sensitive means by a diode connection, said first transistor having a base electrode; a regenerating circuit comprising a second transistor having a base electrode connected with the base electrode of said first transistor for enlarging the output signal of said first transistor, said second transistor having an output terminal; and indicating means connected to the output terminal of said second transistor for indicating the exposure quantity in accordance with the output of said second transistor; and a timing circuit including said light sensitive means, a shutter driving means, switching means for generating a shutter driving signal for activating said shutter driving means when the output voltage of said timing circuit attains a certain predetermined level, said switching means having an input terminal, and a feedback loop connected between the output terminal of said switching means and said indicating means.
Claim 10
Dependent Claim
178 words
A camera including an exposure control apparatus having a light sensitive means for generating a control signal comprising, in combination, a first transistor connected to said light sensitive means and operable to compress the output signal of said light sensitive means by a diode connection, said first transistor having a base electrode; a regenerating circuit comprising a second transistor having a base electrode connected with the base electrode of said first transistor for enlarging the output signal of said first transistor, said second transistor having an output terminal; and indicating means connected to the output terminal of said second transistor for indicating the exposure quantity in accordance with the output of said second transistor; and a timing circuit including said light sensitive means, a shutter driving means, switching means for generating a shutter driving signal for activating said shutter driving means when the output voltage of said timing circuit attains a certain predetermined level, said switching means having an input terminal, and a feedback loop connected between the output terminal of said switching means and said indicating means.
Claim 11
Dependent Claim
26 words
A camera according to claim 8, wherein said feed back loop comprises a diode for allowing the exciting current to flow along a certain predetermined direction.
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) | 1979-04-06 | 1979-10-06 | 1980-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-06 | 1983-10-06 | 1984-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-06 | 1987-10-06 | 1988-04-06 | $7700.00 | Window Closed / Lapsed |