US3769887A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical shutter-control systems for cameras
Assignee: Pentax Corp
•
Filing: 1972-05-19
•
Granted: 1973-11-06
•
Expires: 1992-05-19
Abstract
Abstract An electrical shutter-control system to be used in a camera. The system includes a solenoid which responds to a signal for initiating shutter-closing operations. A signal-transmitting circuit transmits the signal to the solenoid and receives one of a plurality of timing signals from a timing circuit which is automatically operated to select a timing signal which will provide the best exposure. A signal-altering circuit detects when the conditions require a change in the selected timing signal for improving the exposure, and this signal-altering circuit measures the extent to which the selected timing signal should be changed and alters the timing signal accordingly so that the altered timing signal is transmitted to the solenoid for improving the exposure. The alteration in the timing signal is determined in accordance with a fractional interval of time between the time increments corresponding to the timing signals, so as to achieve a continuous exposure time adjustment, or according to non-linear film characteristics to compensate for the latter characteristics, or in accordance with both of these factors.
Inventors
- 👤 T Nobusawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:46
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083; G03B9/00; G03B9/58
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
239 words
For use in a camera, an electrical shutter-control system comprising electrical means for responding to a signal for initiating shutter-closing operations, signal-transmitting means electrically connected with said electrical means for transmitting said signal thereto, timing circuit means electrically connected with said signal-transmitting means for delivering to the latter, to form at least part of the signal transmitted thereby to said electrical means, one of a plurality of timing signals which differ from each other by increments corresponding to different time intervals, electrical selecting means electrically connected with said timing circuit means for selecting from the latter, to be delivered to said signaltransmitting means, that one of said plurality of timing signals which will provide the best exposure, electrical operating means electrically connected with said selecting means for operating the latter to select said one timing signal, and electrical signal-altering means for automatically detecting when the photographing conditions require a change in said one timing signal to improve the exposure and for determining the extent to which said one timing signal should be changed to improve the exposure, said signal-altering means being electrically connected with said signal-transmitting means for altering said one timing signal received thereby to the extent determined by said signalaltering means before a signal is transmitted by said signaltransmitting means to said electrical means for initiating shutter-closing operations, whereby the latter electrical means will receive a timing signal which, if necessary, is altered to improve the exposure.
Claim 2
Dependent Claim
239 words
For use in a camera, an electrical shutter-control system comprising electrical means for responding to a signal for initiating shutter-closing operations, signal-transmitting means electrically connected with said electrical means for transmitting said signal thereto, timing circuit means electrically connected with said signal-transmitting means for delivering to the latter, to form at least part of the signal transmitted thereby to said electrical means, one of a plurality of timing signals which differ from each other by increments corresponding to different time intervals, electrical selecting means electrically connected with said timing circuit means for selecting from the latter, to be delivered to said signaltransmitting means, that one of said plurality of timing signals which will provide the best exposure, electrical operating means electrically connected with said selecting means for operating the latter to select said one timing signal, and electrical signal-altering means for automatically detecting when the photographing conditions require a change in said one timing signal to improve the exposure and for determining the extent to which said one timing signal should be changed to improve the exposure, said signal-altering means being electrically connected with said signal-transmitting means for altering said one timing signal received thereby to the extent determined by said signalaltering means before a signal is transmitted by said signaltransmitting means to said electrical means for initiating shutter-closing operations, whereby the latter electrical means will receive a timing signal which, if necessary, is altered to improve the exposure.
Claim 3
Dependent Claim
56 words
The combination of claim 1 and wherein said signal-altering means automatically detects when said timing signal should be altered to correspond to a time interval between the intervals corresponding to said increments to cooperate with said timing circuit means for achieving a continuously adjustable exposure time signal for said electrical means which initiates the shutter-closing operations.
Claim 4
Dependent Claim
32 words
The combination of claim 1 and wherein said signal-altering means automatically detects when the timing signal should be altered to confrom more closely to the characteristics of the film which is exposed.
Claim 5
Dependent Claim
84 words
The combination of claim 1 and wherein said signal-altering means detects on the one hand when said one timing signal should be altered to provide a signal corresponding to a time interval between those corresponding to said increments, to achieve a continuous exposure-time control, and on the other hand to detect when said one timing signal should be altered in accordance with the characteristics of the film which is exposed, for altering said one timing signal in accordance with both of the latter factors.
Claim 6
Dependent Claim
39 words
The combination of claim 1 and wherein said signal-transmitting means includes a pair of electrical components one of which is a transistor and the other of which is a capacitor, said signal-altering means being electrically connected with said transistor.
Claim 7
Dependent Claim
38 words
The combination of claim 1 and wherein said signal-transmitting means includes a pair of components one of which is a transistor and the other of which is a capacitor, said signal-altering means being electrically connected with said capacitor.
Claim 8
Dependent Claim
115 words
The combination of claim 1 and wherein said operating means includes a light-responsive circuit electrically connected with said selecting means for operat-ing the latter in response to lighting conditions, said signal-altering means being electrically connected with said selecting means to be operated thereby also for selecting one of a plurality of signals, said signal-altering means including a light-responsive means for altering the signal of said signal-altering means selected by said selecting means, and said signal-altering means further including a capacitor means to be charged with a charge correspondIng to the required alteration of said one timing signal, said capacitor means being electrically connected to said signal-transmitting means for altering said one timing signal, if necessary.
Claim 9
Dependent Claim
71 words
The combination of claim 7 and wherein said signal-altering means includes a plurality of parallel-connected circuits one of which is selected by said selecting means, said circuits respectively corresponding to different ranges of light intensity and respectively including resistors which in light ranges where the film in the camera does not respond linearly to change in light intensity provide resistance values which will automatically compensate for the characteristics of the film.
Claim 10
Dependent Claim
106 words
The combination of claim 1 and wherein said operating means includes an oscillating circuit means electrically connected with said selecting means for cyclically delivering operating pulses thereto, said signal-altering means including a memory circuit means for cyclically storing electrical quantities corresponding to fractions of said time intervals occurring between said operating pulses, and light-responsive circuit means electrically connected with said operating means for determining the duration of operation thereof, said light-responsive circuit means also being connected with said signal-altering means for actuating the latter to transmit to said signal-transmitting means any quantity stored by said signal-altering means when the operation of said operating means is terminated.
Claim 11
Dependent Claim
60 words
The combination of claim 9 and wherein a second light-responsive circuit means is electrically connected with said signal-transmitting means for responding to a range of light intensity at which film in the camera does not have a linear characteristic with respect to the change in light intensity, said second light-responsive means altering the signal in accordance with the film characteristics.
Claim 12
Dependent Claim
71 words
The combination of claim 9 and wherein a second light-responsive circuit means is electrically connected with said signal-altering means for automatically responding to a range of light intensity at which the film in the camera does not have a linear relationship with respect to the light intensity, for altering the quantity stored by said signal-altering means to compensate for the non-linear characteristic of the film at said range of light intensity.
Claim 13
Dependent Claim
136 words
The combination of claim 1 and wherein said operating means includes an oscillating circuit means electrically connected with said selecting means for delivering operating pulses thereto, said signal-altering means being electrically connected with said oscillating circuit means to be operated thereby for storing electrical quantities cyclically between said operating pulses and having magnitudes which gradually increase from one pulse to the next, so that when said operating means stops operating at an instant between pulses the stored electrical quantity of said signal-altering means will form an altering signal to be delivered to said signal-transmitting means, light-responsive circuit means forming part of said operating means for determining the operation thereof in accordance with the lighting conditions, and time-limiting circuit means electrically connected with said operating circuit means for limiting the operation thereof to a predetermined time interval.
Claim 14
Dependent Claim
82 words
The combination of claim 6 and wherein said signal-altering means includes a light-responsive component electrically connected with said capacitor for altering the charge thereof, an adjustable diaphragm coacting with said light-responsive component for adjusting the amount of light received thereby so as to adjust the extent to which the charge on the capacitor is altered by said light-responsive component, and said signal-altering means including a diaphragm-adjusting means operatively connected with said diaphragm for adjusting the latter to alter said one timing signal.
Claim 15
Dependent Claim
23 words
The combination of claim 6 and wherein said signal-altering means includes a transistor electrically cOnnected with said capacitor for altering the charge thereof.
Claim 16
Dependent Claim
15 words
The combination of claim 9 and wherein said oscillating circuit means includes a unijunction transistor.
Claim 17
Dependent Claim
38 words
The combination of claim 9 and wherein said oscillating circuit means includes a rotary variable resistor and a motor operatively connected thereto for continuously operating the same during said duration of operation determined by said light-responsive circuit means.
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) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |