US5250977A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic flash unit
Assignee: Panasonic Photo and Lighting Co Ltd
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Filing: 1992-09-11
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Granted: 1993-10-05
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Expires: 2012-09-11
Abstract
Abstract An electronic flash unit being effective in emitting light repeatedly at high speed by boosting an applying voltage between main electrodes of a flash discharge tube twice or more as much as a charged voltage in a main capacitor connected parallel to a high voltage DC power source, wherein the electronic flash device has a plurality of boosting capacitors connected with the flash discharge tube through plural second control switches respectively and a common circuit including an insulated gate bipolar transistor IGBT, the main capacitor and a first control switch for selective excitations, and also connected with a primary winding of a trigger transformer via a trigger capacitor, a diode and so on for charges during being un-excited, and wherein the electronic flash device has a switch control device for selectively turning on one of the plural second switches and for simultaneously turning on the first switch so as to supply a high voltage to the flash discharge tube being combined with the charged voltages of the boosting capacitors and the main capacitor after second et seq light emission operations.
Inventors
- 👤 Kazuo Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:51
CPC Classifications
G; G03; G03B; G03B15/00; G03B15/02; G03B15/03; G03B15/05; H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/34; G03B2215/00; G03B2215/05
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
359 words
An electronic flash unit comprising:. a high voltage DC power source having two terminals; a main capacitor having two terminals connected between the two terminals of said high voltage DC power source and charged by power supply therefrom; a first series member composed of a flash discharge tube and a seriate combination including a first diode having an anode and a cathode and an insulated gate bipolar transistor (IGBT) having a control terminal connected in series to said cathode, said first series member connected between the two terminals of said main capacitor; a second series member composed of a first control switch element having a control terminal and a second diode having an anode and a cathode, said anode being connected to said first control switch element, said second series member connected between two ends of said seriate combination; a parallel member composed of plural series members connected in parallel, each of said series members being composed of a third diode having an anode and a cathode and a second control switch element having a control terminal, said parallel member connected between two ends of said first diode through a fourth diode having an anode connected with the anode of said first diode; a plurality of voltage boosting capacitors each connected between the anode of said second diode and the cathode of each said third diode; charging means for charging said plurality of voltage boosting capacitors through said third diodes and said second diode; switch control means, in response to a supplied light emission starting signal, for operating said first control switch and also selecting one of said plural second control switch elements to operate individually; driving control circuit connected to said control terminal of said IGBT for controlling a turn-on voltage to be supplied to the control terminal of said IGBT so as to control an on/off state of said IGBT; and a trigger circuit having a third series member composed of a trigger capacitor and a primary winding of a trigger transformer, said third series member connected between two ends of said parallel member through said IGBT, said trigger circuit operating to excite said flash discharge tube.
Claim 2
Dependent Claim
359 words
An electronic flash unit comprising:. a high voltage DC power source having two terminals; a main capacitor having two terminals connected between the two terminals of said high voltage DC power source and charged by power supply therefrom; a first series member composed of a flash discharge tube and a seriate combination including a first diode having an anode and a cathode and an insulated gate bipolar transistor (IGBT) having a control terminal connected in series to said cathode, said first series member connected between the two terminals of said main capacitor; a second series member composed of a first control switch element having a control terminal and a second diode having an anode and a cathode, said anode being connected to said first control switch element, said second series member connected between two ends of said seriate combination; a parallel member composed of plural series members connected in parallel, each of said series members being composed of a third diode having an anode and a cathode and a second control switch element having a control terminal, said parallel member connected between two ends of said first diode through a fourth diode having an anode connected with the anode of said first diode; a plurality of voltage boosting capacitors each connected between the anode of said second diode and the cathode of each said third diode; charging means for charging said plurality of voltage boosting capacitors through said third diodes and said second diode; switch control means, in response to a supplied light emission starting signal, for operating said first control switch and also selecting one of said plural second control switch elements to operate individually; driving control circuit connected to said control terminal of said IGBT for controlling a turn-on voltage to be supplied to the control terminal of said IGBT so as to control an on/off state of said IGBT; and a trigger circuit having a third series member composed of a trigger capacitor and a primary winding of a trigger transformer, said third series member connected between two ends of said parallel member through said IGBT, said trigger circuit operating to excite said flash discharge tube.
Claim 3
Dependent Claim
116 words
An electronic flash unit according to claim 1, wherein said switch control means comprises: light emission control means composed of an input terminal for receiving a light emission starting signal, first output terminals for outputting a first output signal for selectively operating said second control switch elements in response to said light emission starting signal, and a second output terminal for outputting a second output signal for operating said first control switch element in response to said light emission starting signal; and a driving circuit having an input terminal receiving a driving voltage, said driving circuit, in response to said second output signal, supplying said driving voltage to said first control switch element to turn on.
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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) | 1996-10-04 | 1997-04-05 | 1997-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-04 | 2001-04-05 | 2001-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-04 | 2005-04-05 | 2005-10-05 | $7700.00 | Window Closed / Lapsed |