Patent US3757654A successfully refreshed from Google Patents.
US3757654A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camera having automatic exposure and automatic flash controls
Assignee: Pentax Corp
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Filing: 1972-04-10
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Granted: 1973-09-11
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Expires: 1992-04-10
Abstract
Abstract A shutter timing circuit automatically determines when flash will be used and its duration. The timing circuit computes proper shutter speed using film sensitivity, diaphragm valve and scene brightness and compares that with a preset shutter speed. When the computed exposure time is longer that the preset time, an enabling circuit allows flash to be triggered when the shutter is opened. The actual speed of the shutter is determined by the timing circuit. If flash is used, the flash is terminated and the shutter closed at the same time by the timing circuit. The diaphragm, film sensitivity and brightness inputs are logarithmically compressed prior to computation of the proper shutter speed and the resultant computed valve is logarithmically expanded prior to timing of the exposure.
Inventors
- 👤 C Mori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:47
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
221 words
In a camera, electrical computing means for computing from electrical factors which respectively correspond to aperture, film speed, and lighting conditions at the object to be photographed, an electrical quantity corresponding to the exposure time required for proper exposure in accordance with said factors, operator-actuated electrical selecting means for selecting an electrical quantity corresponding to an exposure time selected by the operator, electrical comparing means electrically connected with said selecting means and computing means for comparing said quantities and for automatically assuming a given condition when the exposure time corresponding to said computed quantity is greater than the exposure time corresponding to said selected quantity, flash means for providing additional illumination at the object to be photographed, flash-actuating means electrically connected to said comparing means and said flash means for automatically responding to said condition of said comparing means for actuating said flash means to provide said additional illumination when the exposure time corresponding to said computed quantity is greater than the exposure time corresponding to said selected quantity, electrical timing means electrically connected with said computing meaNs for determining a proper exposure time according to all of said factors with or without said additional illumination, and exposure-terminating means electrically connected with said timing means to be actuated thereby for terminating an exposure after an interval determined by said timing means.
Claim 2
Dependent Claim
221 words
In a camera, electrical computing means for computing from electrical factors which respectively correspond to aperture, film speed, and lighting conditions at the object to be photographed, an electrical quantity corresponding to the exposure time required for proper exposure in accordance with said factors, operator-actuated electrical selecting means for selecting an electrical quantity corresponding to an exposure time selected by the operator, electrical comparing means electrically connected with said selecting means and computing means for comparing said quantities and for automatically assuming a given condition when the exposure time corresponding to said computed quantity is greater than the exposure time corresponding to said selected quantity, flash means for providing additional illumination at the object to be photographed, flash-actuating means electrically connected to said comparing means and said flash means for automatically responding to said condition of said comparing means for actuating said flash means to provide said additional illumination when the exposure time corresponding to said computed quantity is greater than the exposure time corresponding to said selected quantity, electrical timing means electrically connected with said computing meaNs for determining a proper exposure time according to all of said factors with or without said additional illumination, and exposure-terminating means electrically connected with said timing means to be actuated thereby for terminating an exposure after an interval determined by said timing means.
Claim 3
Dependent Claim
102 words
The combination of claim 1 and wherein said computing means includes a conductor for conducting an electrical current which forms said computed quantity, said selecting means being in the form of a variable resistor connected in series with said conductor and providing a resistance value which forms said selected quantity, whereby both of said quantities provide at said conductor and resistor a voltage drop whose magnitude corresponds to the magnitudes of said quantities, and said comparing means being electrically connected with said resistor and conductor for responding to said voltage drop to determine whether or not said comparing means assumes said condition.
Claim 4
Dependent Claim
99 words
The combination of claim 1 and wherein said exposure-terminating means is in the form of an electromagnetic means for terminating the exposure, a pair of transistor means connected electrically with said electromagnetic means for controlling the latter, one of said transistor means being electrically connected with said comparing means to respond to operation thereof for controlling said electromagnetic means when said comparing means does not assume said condition and the other of said transistor means being electrically connected with said flash-actuating means to respond to operation thereof for controlling said electromagnetic means when said comparing means assumes said condition.
Claim 5
Dependent Claim
33 words
The combination of claim 3 and wherein a delay means is electrically connected with said other transistor means for adapting the control of said electromagnetic means to the operation of said flash means.
Claim 6
Dependent Claim
112 words
The combination of claim 1 and wherein an external photosensitive means is electrically connected with said computing means for feeding the factor of lighting conditions at the object to be photographed to said computing means prior to and during film exposure with light which is received from the object to be photographed and which is external to an objective of the camera, internal photosensitive means for receiving light from the object after the light has passed through the camera objective, and electrical compensating means electrically connected with said external and internal photosensitive means for compensating the output of said external photosensitive means in accordance with the output of said internal photosensitive means.
Claim 7
Dependent Claim
33 words
The combination of claim 1 and wherein a switch means is electrically connected with said timing means for rendering the latter operative immediately subsequent to comparing of said quantities by said comparing means.
Claim 8
Dependent Claim
70 words
The combination of claim 1 and wherein a flash-terminating means is electrically connected with said flash means for terminating the operation thereof, and SCR means electrically connected with said timing means, said flash-terminating means, and said exposure-terminating means for responding to said timing means to actuate said exposure-terminating means after elapse of said interval and to actuate said flash-terminating means after said interval when said comparing means assumes said condition.
Claim 9
Dependent Claim
53 words
The combination of claim 1 and wherein said comparing means includes a transistor which is in a non-conductive state when said comparing means assumes said condition, said flash-actuating means including a transistor electrically connected with said transistor of said comparing means for assuming a conductive state when said comparing means assumes said condition.
Claim 10
Dependent Claim
111 words
The combination of claim 8 and wherein said exposure-terminating means is in the form of an electromagnetic means, and a pair of parallel-connected transistors connected electrically to said electromagnetic means for controlling the latter to terminate an exposure, one of said pair of transisTors being electrically connected with said transistor of said flash-actuating means to be rendered operative for controlling said electromagnetic means when said transistor of said flash-actuating means is conductive, and the other of said transistors being electrically connected to said transistor of said comparing means for controlling said electromagnetic means when said transistor of said comparing means does not assume said condition and is in a conductive state.
Claim 11
Dependent Claim
160 words
In a camera, electromagnetic means for terminating an exposure, a pair of parallel-connected transistors electrically connected with said electromagnetic means, flash means for providing flash illumination, said flash means being electrically connected to one of said pair of transistors for acting through the latter on said electromagnetic means to control the latter for terminating an exposure made with flash illumination, and additional transistor means for determining whether exposure will be made with or without flash illumination, said additional transistor means being electrically connected with said flash means for rendering the latter operative when a determination is made by said additional transistor means that an exposure with flash illumination will be carried out, said additional transistor means being electrically connected with the other of said pair of parallel-connected transistors for acting through the latter on said electromagnetic means to control the latter for terminating an exposure when said additional transistor means determines that an exposure is being made without flash illumination.
Claim 12
Dependent Claim
160 words
In a camera, electromagnetic means for terminating an exposure, a pair of parallel-connected transistors electrically connected with said electromagnetic means, flash means for providing flash illumination, said flash means being electrically connected to one of said pair of transistors for acting through the latter on said electromagnetic means to control the latter for terminating an exposure made with flash illumination, and additional transistor means for determining whether exposure will be made with or without flash illumination, said additional transistor means being electrically connected with said flash means for rendering the latter operative when a determination is made by said additional transistor means that an exposure with flash illumination will be carried out, said additional transistor means being electrically connected with the other of said pair of parallel-connected transistors for acting through the latter on said electromagnetic means to control the latter for terminating an exposure when said additional transistor means determines that an exposure is being made without flash illumination.
Claim 13
Dependent Claim
26 words
The combination of claim 10 and wherein a delay means is electrically connected between said one of said pair of parallel-connected transistors and said flash means.
Claim 14
Dependent Claim
88 words
The combination of claim 10 and wherein an input means is electrically connected with said additional transistor means for delivering to the latter an input in accordance with the difference between an automatically computed exposure time and an operator-selected exposure time, said additional transistor means rendering said flash means operative when the computed exposure time is greater than the selected exposure time and controlling said electromagnetic means through the other of said pair of parallel-connected transistors when the computed exposure time is less than the selected exposure time.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |