US4458995A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camera flash light control circuitry
Assignee: Minolta Co Ltd
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Filing: 1982-09-30
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Granted: 1984-07-10
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Expires: 2002-09-30
Abstract
Abstract A dedicated electronic flash device capable of being combined with a camera and receiving a flash device identifying signal at a common terminal for establishing automatic aperture size control in a flash light exposure mode, and establishing manual aperture size control in the absence of the identifying signal. A flash light emission terminating signal, having a level greater than the identifying signal, is transmitted from the camera to the dedicated electronic flash device through the common terminal. The camera is capable of changing the automatic exposure time control and the aperture size control modes into respective flash light exposure modes in response to a charge completion signal transmitted from the electronic flash device through another terminal.
Inventors
- 👤 Tokuji Ishida
- 👤 Hiroshi Hosomizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:57
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/16
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
181 words
In a dedicated electronic flash device capable of being combined with a camera adapted to transmit a first signal to the dedicated electronic flash device and to receive a second signal therefrom, the first signal being at a first level to terminate the flash light emission of the dedicated electronic flash device and the second signal being at a second level less than the first level, but greater than a limit sensed by the camera, to communicate that the dedicated electronic flash device is combined with the camera, said dedicated electronic flash device comprising: a common terminal connectable to the camera for receiving said first signal and for transmitting said second signal; means connected to said common terminal for generating said second signal; means connected to said common terminal for detecting that the first signal is received; means for emitting a flash of light; means for initiating the flash light emission of said emitting means; and means responsive to said detecting means for terminating the flash light emission when the receipt of said first signal is detected by said detecting means.
Claim 2
Dependent Claim
181 words
In a dedicated electronic flash device capable of being combined with a camera adapted to transmit a first signal to the dedicated electronic flash device and to receive a second signal therefrom, the first signal being at a first level to terminate the flash light emission of the dedicated electronic flash device and the second signal being at a second level less than the first level, but greater than a limit sensed by the camera, to communicate that the dedicated electronic flash device is combined with the camera, said dedicated electronic flash device comprising: a common terminal connectable to the camera for receiving said first signal and for transmitting said second signal; means connected to said common terminal for generating said second signal; means connected to said common terminal for detecting that the first signal is received; means for emitting a flash of light; means for initiating the flash light emission of said emitting means; and means responsive to said detecting means for terminating the flash light emission when the receipt of said first signal is detected by said detecting means.
Claim 3
Dependent Claim
32 words
The dedicated electronic flash device as in claim 1, wherein said detecting means includes a level detector having level sensitivity greater than said second level to only respond to said first signal.
Claim 4
Dependent Claim
70 words
The dedicated electronic flash device as in claim 2, wherein said level detector includes means for providing a reference level greater than said second level, and a level comparator having a first input terminal connected to said reference level providing means, a second input terminal connected to said common terminal and an output terminal for producing an output with the level at said common terminal greater than said reference level.
Claim 5
Dependent Claim
70 words
The dedicated electronic flash device as in claim 3, wherein said reference level providing means includes a voltage divider network and a constant current source for causing a constant current through said voltage divider network, and said voltage divider network includes means for providing the reference level to said first input terminal, and wherein said generating means includes means for taking out the second signal from said voltage divider network.
Claim 6
Dependent Claim
36 words
The dedicated electronic flash device as in claim 4, wherein said taking out means includes a buffer for preventing said reference level from being influenced by a change in the voltage level at said common terminal.
Claim 7
Dependent Claim
36 words
The dedicated electronic flash device as in claim 1 further comprising a second terminal connectable to the camera, wherein said initiating means is responsive to a synchro signal received from the camera through said second terminal.
Claim 8
Dependent Claim
32 words
The dedicated electronic flash device as in claim 6 further comprising a third terminal connectable to the camera, and means connected to said third terminal for producing a flash light preparation signal.
Claim 9
Dependent Claim
33 words
The dedicated electronic flash device as in claim 7 further comprising means for preventing operation of said preparation signal producing means in response to appearance of the synchro signal at said second terminal.
Claim 10
Dependent Claim
28 words
The dedicated electronic flash device as in claim 8 further comprising means for disabling said terminating means with the absence of the synchro signal at said second terminal.
Claim 11
Dependent Claim
29 words
The dedicated electronic flash device as in claim 9 further comprising a fourth terminal connectable to the camera for interconnecting the camera and the dedicated electronic flash device grounds.
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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) | 1987-07-10 | 1988-01-09 | 1988-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-10 | 1992-01-09 | 1992-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-10 | 1996-01-09 | 1996-07-10 | $7700.00 | Window Closed / Lapsed |