US5146250A
Expired / Lapsed
US
⏱️ 0.0 years remaining
External power source for electronic flash
Assignee: Nikon Corp
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Filing: 1991-02-05
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Granted: 1992-09-08
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Expires: 2011-02-05
Abstract
Abstract An external power source, for an electronic flash unit, includes a battery, a voltage step-up circuit for starting a voltage step-up operation of the battery voltage in response to a start signal and terminating the step-up operation in response to a stop signal, a voltage detecting circuit for detecting that the output voltage of the voltage step-up circuit has reached a predetermined value, and a voltage step-up control circuit for releasing the start signal and the stop signal. The control circuit releases the start signal in response to a synchronization signal from the camera or in response to the detection of flash emission by a flash detecting circuit, and releases the stop signal upon detection by the detecting circuit that the output voltage has reached the predetermined value.
Inventors
- 👤 Hiroshi Sakamoto
- 👤 Nobuyoshi Hagiuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:59
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
163 words
An external power source to be detachably connected to an electronic flash unit which has a main capacitor for storing charge therein and flash means for emitting light on the basis of charge stored in said main capacitor, comprising: a battery; voltage step-up means for elevating voltage from said battery to apply the elevated voltage to said main capacitor; flash detecting means for detecting flash emission of said flash means and producing a flash detection signal; voltage detecting means for detecting that the output voltage of said voltage step-up means has reached a predetermined value and producing a voltage detection signal; and voltage step-up control means for releasing a start signal in response to said flash detection signal, and releasing a stop signal in response to said voltage detection signal, said voltage step-up means starting a voltage step-up operation for elevating the voltage of said battery in response to said start signal and terminating said step-up operation in response to said stop signal.
Claim 2
Dependent Claim
163 words
An external power source to be detachably connected to an electronic flash unit which has a main capacitor for storing charge therein and flash means for emitting light on the basis of charge stored in said main capacitor, comprising: a battery; voltage step-up means for elevating voltage from said battery to apply the elevated voltage to said main capacitor; flash detecting means for detecting flash emission of said flash means and producing a flash detection signal; voltage detecting means for detecting that the output voltage of said voltage step-up means has reached a predetermined value and producing a voltage detection signal; and voltage step-up control means for releasing a start signal in response to said flash detection signal, and releasing a stop signal in response to said voltage detection signal, said voltage step-up means starting a voltage step-up operation for elevating the voltage of said battery in response to said start signal and terminating said step-up operation in response to said stop signal.
Claim 3
Dependent Claim
28 words
An external power source according to claim 1, wherein said flash detecting means detects flash emission of said flash means irrespective of a shutter operation of said camera.
Claim 4
Dependent Claim
58 words
An external power source according to claim 2, wherein said voltage step-up means comprises output terminals for applying the elevated voltage to said main capacitor, and wherein said flash detecting means comprises a detecting capacitor electrically connected to said output terminals and detects that the voltage of said detecting capacitor decreases and thereafter produces said flash detection signal.
Claim 5
Dependent Claim
48 words
An external power source according to claim 3, wherein said flash detecting means comprises a detecting transistor provided with an emitter terminal and a base terminal, said emitter terminal being connected to one of said output terminals, and said base terminal being connected to a power source line.
Claim 6
Dependent Claim
59 words
An external power source according to claim 3, which further comprises timer means for counting time in response to a synchronization signal for flash emission supplied from a camera and producing a timer signal when said timer means has counted a predetermined time, wherein said voltage step-up control means releases said stop signal in response to said timer signal.
Claim 7
Dependent Claim
59 words
An external power source according to claim 1, which further comprises timer means for counting time in response to a synchronization signal for flash emission supplied from a camera and producing a timer signal when said timer means has counted a predetermined time, wherein said voltage step-up control means releases said stop signal in response to said timer signal.
References Cited (Backward Citations)
US4430602A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-08 | 1996-03-09 | 1996-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-08 | 2000-03-09 | 2000-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-08 | 2004-03-09 | 2004-09-08 | $7700.00 | Window Closed / Lapsed |