US3626825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiation-sensitive camera shutter and aperture control systems
Assignee: Texas Instruments Inc
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Filing: 1970-05-28
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Granted: 1971-12-14
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Expires: 1990-05-28
Abstract
Abstract A voltage that varies linearly with light intensity variation is generated by an amplifier having a differential input stage connected to a light-responsive diode. Two high-gain transistors are included in the differential input stage to provide amplification of the signal currents of the light-responsive diode. In a camera shutter and aperture control system, the linearly varying light intensity voltage is amplified to control two threshold detector circuits. An inhibiting circuit prevents one of the threshold detector circuits from responding to the light intensity voltage until the first threshold circuit has completed its desired operation.
Inventors
- 👤 Kenneth E Years
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:57
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/42; G01J1/4209; G01J1/4214; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/087
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
189 words
In a camera shutter and aperture control system, the combination comprising: a light-responsive photosensor generating a current signal that varies with light intensity incident thereon, an amplifier including a differential input section connected to said light-responsive photosensor and having a first feedback loop for relating the amplifier output proportionately to the diode-generated signal and a second feedback loop for relating the amplifier output to the time integral of the photosensor generated signal, switching means for connecting each of the feedback loops separately to said amplifier output, a second amplifier having an output that varies with film speed and the output of said first amplifier, a first threshold detector responsive to the output of said second amplifier when said switching means connects the first feedback loop across said first amplifier for controlling the camera aperture setting, a second threshold detector responsive to the output of said second amplifier when said switching means connects the second feedback loop across said first amplifier for controlling the camera shutter operation, and means for inhibiting the operation of said second threshold detector until said first threshold detector sets the opening of the camera aperture.
Claim 2
Dependent Claim
189 words
In a camera shutter and aperture control system, the combination comprising: a light-responsive photosensor generating a current signal that varies with light intensity incident thereon, an amplifier including a differential input section connected to said light-responsive photosensor and having a first feedback loop for relating the amplifier output proportionately to the diode-generated signal and a second feedback loop for relating the amplifier output to the time integral of the photosensor generated signal, switching means for connecting each of the feedback loops separately to said amplifier output, a second amplifier having an output that varies with film speed and the output of said first amplifier, a first threshold detector responsive to the output of said second amplifier when said switching means connects the first feedback loop across said first amplifier for controlling the camera aperture setting, a second threshold detector responsive to the output of said second amplifier when said switching means connects the second feedback loop across said first amplifier for controlling the camera shutter operation, and means for inhibiting the operation of said second threshold detector until said first threshold detector sets the opening of the camera aperture.
Claim 3
Dependent Claim
47 words
In a camera shutter and aperture control system as set forth in claim 1 including timing means connected between the output of said second amplifier and said first threshold detector for controlling the operation of said first detector in accordance with the output of the second amplifier.
Claim 4
Dependent Claim
40 words
In a camera shutter and aperture control system as set forth in claim 2 including means for biasing the second input to the differential section of the first amplifier and one side of said light-responsive photosensor at a reference level.
Claim 5
Dependent Claim
23 words
In a camera shutter and aperture control system as set forth in claim 3 wherein said light-responsive photosensor is a selenium photovoltaic cell.
Claim 6
Dependent Claim
22 words
In a camera shutter and aperture control system as set forth in claim 3 wherein said light-responsive photosensor is a silicon transistor.
Claim 7
Dependent Claim
24 words
In a camera shutter and aperture control system as set forth in claim 5 including means for shunting the collector-base junction of said transistor.
Claim 8
Dependent Claim
24 words
In a camera shutter and aperture control system as set forth in claim 6 including means for biasing the emitter-base junction of said transistor.
Claim 9
Dependent Claim
32 words
In a camera shutter and aperture control system as set forth in claim 7 including an optical filter to limit the response of said transistor to radiant energy in the visible region.
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) | 1974-12-13 | 1975-06-14 | 1975-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-13 | 1979-06-14 | 1979-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-13 | 1983-06-14 | 1983-12-14 | $7700.00 | Window Closed / Lapsed |