US3683769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic flash circuit
Assignee: Canon Inc
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Filing: 1970-06-16
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Granted: 1972-08-15
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Expires: 1990-06-16
Abstract
Abstract In the automatic camera flash circuit disclosed a start switch actuates a time constant circuit. A first semiconductor circuit, controlled by the time constant circuit, operates an electromagnet. A power source and a second semiconductor circuit actuates a flash device. The flash device is controlled by the time constant circuit through the second semiconductor circuit.
Inventors
- 👤 Takashi Uchiyama
- 👤 Tadashi Ito
- 👤 Mutsuhide Matsuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:53
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/70
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
76 words
An automatic flashing circuit for a camera comprising a time constant circuit, a start switch for said time constant circuit, a first semiconductor circuit for shutter operation controlled by said time constant circuit, an electromagnet controlled by said time constant circuit through said first semiconductor circuit, a flashing device, a power source and a second semiconductor circuit for flash actuation, said flashing device being also controlled by said time constant circuit through said second semiconductor circuit.
Claim 2
Dependent Claim
76 words
An automatic flashing circuit for a camera comprising a time constant circuit, a start switch for said time constant circuit, a first semiconductor circuit for shutter operation controlled by said time constant circuit, an electromagnet controlled by said time constant circuit through said first semiconductor circuit, a flashing device, a power source and a second semiconductor circuit for flash actuation, said flashing device being also controlled by said time constant circuit through said second semiconductor circuit.
Claim 3
Dependent Claim
37 words
An automatic flashing circuit for a camera according to claim 1 in which the time constant circuit comprises a capacitor and a variable resistor for setting photographic information such as film sensitivity, object distance or guide number.
Claim 4
Dependent Claim
29 words
An automatic flashing circuit for a camera according to claim 1 in which the first semiconductor circuit comprises at least one P-N-P type transistor and one N-P-N type transistor.
Claim 5
Dependent Claim
46 words
An automatic flashing circuit for a camera according to claim 2, wherein the time constant circuit further comprises a light receiving element for control of automatic exposure, and a change-over switch for selectively connecting either the variable resistor or the light receiving element to the capacitor.
Claim 6
Dependent Claim
75 words
An automatic flashing circuit for a camera comprising a common time constant circuit, a start switch for said common time constant circuit, a first semiconductor circuit for shutter operation controlled by said common time constant circuit, an electromagnet controlled by said common time constant circuit, a flashing device, a power source for energizing said flashing device, and a second semiconductor circuit controlled by the output of the first semiconductor circuit for actuating said flash device.
Claim 7
Dependent Claim
75 words
An automatic flashing circuit for a camera comprising a common time constant circuit, a start switch for said common time constant circuit, a first semiconductor circuit for shutter operation controlled by said common time constant circuit, an electromagnet controlled by said common time constant circuit, a flashing device, a power source for energizing said flashing device, and a second semiconductor circuit controlled by the output of the first semiconductor circuit for actuating said flash device.
Claim 8
Dependent Claim
20 words
An automatic flashing circuit for a camera according to claim 4 in which the light receiving element is a photoconductor.
Claim 9
Dependent Claim
26 words
An automatic flashing circuit for a camera according to claim 4 in which the change-oVer switch is associated with a change-over member provided in the camera.
Claim 10
Dependent Claim
20 words
An automatic flashing circuit for a camera according to claim 5 in which the second semiconductor is a power transistor.
Claim 11
Dependent Claim
20 words
An automatic flashing circuit for a camera according to claim 5 in which the second semiconductor circuit includes a thyristor.
Claim 12
Dependent Claim
49 words
An automatic flashing circuit for a camera according to claim 5 in which the power source comprises a first power source which is a low voltage battery for actuation of the electromagnet and a second power source which is a high voltage battery for actuation of the flashing device.
Claim 13
Dependent Claim
20 words
An automatic flashing circuit for a camera according to claim 10 in which the flashing device comprises a discharge tube.
Claim 14
Dependent Claim
51 words
An automatic flashing circuit for a camera according to claim 1, wherein the time constant circuit includes a capacitor, said start switch being connected in parallel with said capacitor, said start switch being responsive to shutter opening, said electromagnet being connected to said first semiconductor circuit and associated with shutter closing.
Claim 15
Dependent Claim
19 words
An automatic flashing circuit for a camera according to claim 1, wherein the flashing device comprises a discharge tube.
Claim 16
Dependent Claim
84 words
An automatic flashing circuit for a camera, comprising a common time constant circuit, a start switch for actuating said common time constant circuit, a first semiconductor circuit for shutter operation controlled by said common time constant circuit, an electromagnet controlled by said time constant circuit, a flashing device having a power source, a second semiconductor circuit controlled by said time constant circuit for actuating the flash device, said second semiconductor circuit including a variable element for controlling the actuation time of the flashing device.
Claim 17
Dependent Claim
84 words
An automatic flashing circuit for a camera, comprising a common time constant circuit, a start switch for actuating said common time constant circuit, a first semiconductor circuit for shutter operation controlled by said common time constant circuit, an electromagnet controlled by said time constant circuit, a flashing device having a power source, a second semiconductor circuit controlled by said time constant circuit for actuating the flash device, said second semiconductor circuit including a variable element for controlling the actuation time of the flashing device.
Claim 18
Dependent Claim
33 words
An automatic flashing circuit for a camera according to claim 4, wherein said change-over switch is associated with an activator switch which actuates only when the variable resistor is connected with said capacitor.
References Cited (Backward Citations)
US3418904A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |