US3748978A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure time controls for cameras operating with flash illumination
Assignee: Yashica Co Ltd
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Filing: 1971-11-03
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Granted: 1973-07-31
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Expires: 1991-11-03
Abstract
Abstract A camera which can provide flash illumination, particularly for reducing the exposure time. The camera shutter is automatically closed when the charge of a timing capacitor increases to a given extent. Simultaneously with the creation of the flash illumination, a suitable circuit generates an electrical signal which is used to charge the capacitor so as to coact therewith for achieving a predetermined exposure time. The capacitor is also charged by a photosensitive element which responds to the light created during flash illumination, so that the predetermined exposure time will be reduced to the extent that the capacitor is charged by the photosensitive element.
Inventors
- 👤 H Yoshimura
- 👤 S Nishimura
- 👤 H Takahata
- 👤 A Furuhata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:08
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083; G03B7/16; G03B7/30
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
255 words
In a camera, shutter-opening means for opening a shutter to start an exposure, shutter-closing means for closing the shutter to terminate an exposure, timing circuit means electrically connected with said shutter-closing means for actuating the latter to close the shutter, said timing circuit means including a capacitor means which actuates said shutter-closing means to terminate an exposure when the terminal voltage of said capacitor means rises to a given extent, said timing circuit means also including a photosensitive means for responding to light and electrically connected with said capacitor means for charging the latter in response to light received by said photosensitive means, flash circuit means for creating flash illumination to which said photosensitive means responds when a source of flash illumination is electrically connected with said flash circuit means, signal-generating circuit means electrically connected with said flash circuit means for rendering the latter operative in synchronism with opening of the shutter and for generating an electrical signal simultaneously with the creation of flash illumination by said flash circuit means, and charging means electrically connected with said capacitor means and with said signal-generating circuit means for receiving the electrical signal generated by the latter and for charging said capacitor means to a given extent when said signal is received by said charging means from said signal-generating circuit means, said charging means and capacitor means providing a predetermined exposure time which is diminished by the extent to which the capacitor means is charged by said photosensitive means in response to light received thereby during flash illumination.
Claim 2
Dependent Claim
255 words
In a camera, shutter-opening means for opening a shutter to start an exposure, shutter-closing means for closing the shutter to terminate an exposure, timing circuit means electrically connected with said shutter-closing means for actuating the latter to close the shutter, said timing circuit means including a capacitor means which actuates said shutter-closing means to terminate an exposure when the terminal voltage of said capacitor means rises to a given extent, said timing circuit means also including a photosensitive means for responding to light and electrically connected with said capacitor means for charging the latter in response to light received by said photosensitive means, flash circuit means for creating flash illumination to which said photosensitive means responds when a source of flash illumination is electrically connected with said flash circuit means, signal-generating circuit means electrically connected with said flash circuit means for rendering the latter operative in synchronism with opening of the shutter and for generating an electrical signal simultaneously with the creation of flash illumination by said flash circuit means, and charging means electrically connected with said capacitor means and with said signal-generating circuit means for receiving the electrical signal generated by the latter and for charging said capacitor means to a given extent when said signal is received by said charging means from said signal-generating circuit means, said charging means and capacitor means providing a predetermined exposure time which is diminished by the extent to which the capacitor means is charged by said photosensitive means in response to light received thereby during flash illumination.
Claim 3
Dependent Claim
14 words
The combination of claim 1 and wherein said photosensitive means is a solar battery.
Claim 4
Dependent Claim
26 words
The combination of claim 1 and wherein an electrical connEcting means is provided for removably connecting said flash circuit means electrically with said impulse-generating circuit means.
Claim 5
Dependent Claim
78 words
The combination of claim 3 and wherein said flash circuit means coacts with a source of flash illumination for removably receiving the latter and said source of flash illumination rendering said flash circuit means operative only when said source of flash illumination is connected into said flash circuit means, so that even if the latter remains connected with said signal-generating circuit means said flash circuit means will not operate unless a source of flash illumination is connected therewith.
Claim 6
Dependent Claim
95 words
The combination of claim 1 and wherein said signal-generating circuit means includes a coil for generating said electrical signal when said signal-generating circuit means renders said flash circuit means operative to create a flash, said charging means including an SCR electrically connected with said coil to be rendered conductive by the singal generated thereby, and said charging means including a transistor electrically connected with said capacitor means and with said SCR to be rendered conductive when said SCR is rendered conductive by said electrical signal for then charging said capacitor means to said given extent.
Claim 7
Dependent Claim
35 words
The combination of claim 1 and wherein said charging means includes a monostable multivibrator for receiving said electrical signal from said signal-generating circuit means and for then charging said capacitor means to said given extent.
Claim 8
Dependent Claim
42 words
The combination of claim 6 and wherein said signal-generating circuit means includes a booster transformer electrically connected with said monostable multivibrator and creating said electrical signal when said signal-generating circuit means renders said flash circuit means operative to create the flash illumination.
Claim 9
Dependent Claim
30 words
The combination of claim 1 and wherein said signal-generating circuit means includes only a single switch for rendering said flash circuit means operative in synchronism with opening of the shutter.
Claim 10
Dependent Claim
45 words
The combination of claim 1 and wherein said timing circuit means inclues only a single switch, said switch being a normally closed trigger switch bridging said capacitor means and adapted to be opened when the shutter opens to start the charging of said capacitor means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |