Patent US5408250A successfully refreshed from Google Patents.
Patent US4143955A successfully refreshed from Google Patents.
US4143955A
Expired / Lapsed
US
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Flash synchronization controlling means for program type electric shutters
Assignee: Nidec Precision Corp
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Filing: 1977-05-19
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Granted: 1979-03-13
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Expires: 1997-05-19
Abstract
Abstract A flash synchronization controlling circuit for program type electric shutters. A first switching circuit is utilized for controlling the shutter closing and a second switching circuit is connected to the first switching circuit and utilized for controlling the flash actuation in order that the flash synchronization controlling circuit may be simplified and to provide a very positive and stable flash synchronizing operation. The flash synchronization controlling circuit is arranged so that the switching operation of the second switching circuit can be effected earlier by a predetermined time interval than that of the first switching circuit.
Inventors
- 👤 Kunio Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:39
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/70; G03B15/00; G03B15/02; G03B15/03; G03B15/05; G03B7/00; G03B7/08; G03B7/081; G03B7/083; G03B2215/00; G03B2215/05
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
215 words
A flash synchronization control system for program type electric shutters comprising: at least one set of shutter blades; governor means for upon actuation releasably opening said shutter blades at a low speed; electromagnetic means, responsive to control signals applied thereto, for controllably effecting release of said shutter blades by said governor means to rapidly close said shutter blades; a first switching circuit, responsive to application of a first predetermined voltage to an input terminal, for generating said control signal to said electromagnetic means to effect said release of said shutter blades by said governor means; a second switching circuit, responsive to application of a second predetermined voltage, to an output terminal for generating an activation signal to said flash; means for generating a signal indicative of the brightness of the object to be photographed; and means, responsive to the actuation of said governor means and said brightness signal, for applying said second predetermined voltage to said second switching circuit input terminal and applying said first predetermined voltage to said first switching circuit input terminal a predetermined time interval thereafter, whereby said flash is activated at a time in accordance with the brightness of an object to be photographed after the actuation of said governor means and said shutter blades are closed said predetermined time thereafter.
Claim 2
Dependent Claim
215 words
A flash synchronization control system for program type electric shutters comprising: at least one set of shutter blades; governor means for upon actuation releasably opening said shutter blades at a low speed; electromagnetic means, responsive to control signals applied thereto, for controllably effecting release of said shutter blades by said governor means to rapidly close said shutter blades; a first switching circuit, responsive to application of a first predetermined voltage to an input terminal, for generating said control signal to said electromagnetic means to effect said release of said shutter blades by said governor means; a second switching circuit, responsive to application of a second predetermined voltage, to an output terminal for generating an activation signal to said flash; means for generating a signal indicative of the brightness of the object to be photographed; and means, responsive to the actuation of said governor means and said brightness signal, for applying said second predetermined voltage to said second switching circuit input terminal and applying said first predetermined voltage to said first switching circuit input terminal a predetermined time interval thereafter, whereby said flash is activated at a time in accordance with the brightness of an object to be photographed after the actuation of said governor means and said shutter blades are closed said predetermined time thereafter.
Claim 3
Dependent Claim
200 words
The system of claim 1 wherein: said means for generating said brightness signal comprises photoelectric means for generating a constant current of an amplitude in accordance with the brightness of said object to be photographed; and wherein further said first and second means for applying said predetermined voltages comprises: a resistance, connected between said first switching circuit input terminal and said second switching circuit input terminal, and receptive of said constant current at the connection to said second switching circuit input terminal; a capacitance connected between said first switching circuit input terminal and a ground potential, and further switch means, cooperating with said governor means and coupled across said capacitance for initially applying said constant current to said capacitance in accordance with actuation of said governor means; whereby the respective voltages at said first switching circuit input terminal and said second switching circuit input terminal thereafter increase a substantially linear rate in accordance with the amplitude of said constant current, the instantaneous voltage at said second switching circuit input terminal being equal to the sum of the instantaneous voltage at said first switching circuit input terminal and a constant proportional to the product of said resistance and said current amplitude.
Claim 4
Dependent Claim
20 words
The system of claim 2 wherein said resistance is a variable resistor whereby said predetermined time interval can be varied.
Claim 5
Dependent Claim
53 words
The system of claim 2 wherein said first and second predetermined voltages are determined by voltages at respective second input terminals of said first and second switching circuits, and said respective second input terminals are connected at respective points in a voltage divider network to at least partially establish said predetermined time interval.
Claim 6
Dependent Claim
14 words
The system of claim 4 wherein said voltage divider network includes a variable resistance.
Claim 7
Dependent Claim
13 words
The system of claim 5 wherein said voltage divider further includes a diode.
Claim 8
Dependent Claim
53 words
The system of claim 1 wherein said first and second predetermined voltages are determined by voltages at respective second input terminals of said first and second switching circuits, and said respective second input terminals are connected at respective points in a voltage divider network to at least partially establish said predetermined time interval.
Claim 9
Dependent Claim
14 words
The system of claim 7 wherein said voltage divider network includes a variable resistance.
Claim 10
Dependent Claim
13 words
The system of claim 8 wherein said voltage divider further includes a diode.
Claim 11
Dependent Claim
80 words
The system of claim 2 wherein said first and second predetermined voltages are determined by voltages at respective second input terminals of said first and second switching circuits, and wherein said system further includes: a memory capacitor; means for charging said memory capacitor to a potential in accordance with the opening size of said shutter; and means for coupling said memory capacitor to said first and second switching circuit second terminals, to establish thereby said first and second predetermined voltages.
Claim 12
Dependent Claim
20 words
The system of claim 10 wherein said first and second switching circuits each comprises a pair of emitter coupled transistors.
Claim 13
Dependent Claim
17 words
The system of claim 10 wherein said first and second switching circuits each comprises a differential amplifier.
Claim 14
Dependent Claim
20 words
The system of claim 2 wherein said first and second switching circuits each comprises a pair of emitter coupled transistors.
Claim 15
Dependent Claim
17 words
The system of claim 2 wherein said first and second switching circuits each comprises a differential amplifier.
Claim 16
Dependent Claim
20 words
The system of claim 1 wherein said first and second switching circuits each comprises a pair of emitter coupled transistors.
Claim 17
Dependent Claim
17 words
The system of claim 1 wherein said first and second switching circuits each comprises a differential amplifier.
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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) | 1982-03-12 | 1982-09-11 | 1983-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-12 | 1986-09-11 | 1987-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-12 | 1990-09-11 | 1991-03-13 | $7700.00 | Window Closed / Lapsed |