US4603954A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synchronizing device for flash photography
Assignee: Canon Inc
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Filing: 1984-12-19
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Granted: 1986-08-05
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Expires: 2004-12-19
Abstract
Abstract The object distance from a range finder is factored into the guide number of the strobe to obtain an aperture value in binary form by a decoder. As the size of aperture opening of the shutter is increasing from the minimum to the maximum, a counter counts up a corresponding number of pulses in addition to the preset value of film speed. The output of the counter is compared with the output of the decoder by a comparator upon coincidence to produce an actuating signal for the strobe.
Inventors
- 👤 Akira Egawa
- 👤 Takanori Kodaira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:23
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/16; G03B15/00; G03B15/02; G03B15/03; G03B15/05
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
115 words
A flash control device for flash photography, comprising: (a) distance information transfer means for transferring information of distance to an object; (b) film sensitivity information transfer means for transfering film sensitivity information; (c) aperture information transfer means for transferring aperture opening information; (d) flash control means for producing a flash signal for flash photography in response to a predetermined state of an output of said aperture information transfer means relative to an output of said distance information transfer means and an output of said film sensitivity information transfer means; and (e) prevention means for preventing said flash signal from being produced by said flash control means until the aperture opening information reaches a predetermined value.
Claim 2
Dependent Claim
115 words
A flash control device for flash photography, comprising: (a) distance information transfer means for transferring information of distance to an object; (b) film sensitivity information transfer means for transfering film sensitivity information; (c) aperture information transfer means for transferring aperture opening information; (d) flash control means for producing a flash signal for flash photography in response to a predetermined state of an output of said aperture information transfer means relative to an output of said distance information transfer means and an output of said film sensitivity information transfer means; and (e) prevention means for preventing said flash signal from being produced by said flash control means until the aperture opening information reaches a predetermined value.
Claim 3
Dependent Claim
27 words
A flash control device according to claim 1, wherein said aperture information transfer means includes opening position detection means for detecting an opening position of the aperture.
Claim 4
Dependent Claim
18 words
A flash control device according to claim 2, wherein said opening position detecting means includes light detection means.
Claim 5
Dependent Claim
16 words
A flash control device according to claim 3, wherein said light detection means includes a photo-interrupter.
Claim 6
Dependent Claim
58 words
A flash control device according to claim 3, wherein said opening position detection means includes count means for counting rises and descents of the output of said light detection means, and the aperture information transfer means is arranged to detect an amount of opening of the aperture on the basis of the value counted by the count means.
Claim 7
Dependent Claim
30 words
A flash control device according to claim 1, which further comprises compensation means for compensating the output of said flash lighting control means in response to changes in photographic conditions.
Claim 8
Dependent Claim
22 words
A flash control device according to claim 6, wherein said compensation means includes response means for responding to changes in focal distance.
Claim 9
Dependent Claim
26 words
A flash control device according to claim 6, wherein said compensation means includes response means for responding to changes in flash lighting amount of a strobe.
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) | 1989-08-04 | 1990-02-03 | 1990-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-04 | 1994-02-03 | 1994-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-04 | 1998-02-03 | 1998-08-05 | $7700.00 | Window Closed / Lapsed |