Patent US4908552A successfully refreshed from Google Patents.
US4908552A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic flash unit
Assignee: Canon Inc
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Filing: 1988-12-09
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Granted: 1990-03-13
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Expires: 2008-12-09
Abstract
Abstract This invention concerns with an electronic flash unit in which, as two capacitors of large and small capacitances are charged, even when a trigger operation is actuated before the capacitor of large capacitance is fully charged, it is made possible with the help of the charge from the capacitor of small capacitance to fire the flash tube. Particularly in application of the invention to the above-described type of electronic flash unit, as the battery for use in charging the capacitors also serves to drive another load for a time which can fall in coincidence with the period of charging the capacitors, when the driving of the load is started, the charging of the capacitor of large capacitance is inhibited while the charging of the capacitor of small capacitance is permitted to go on, thereby it being made possible to carry out the driving of the load with high reliability so that the correct flash exposure is made while still maintaining the quickness of snap shots.
Inventors
- 👤 Toshiyuki Kumakura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:15
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; G; G03; G03B; G03B15/00; G03B15/02; G03B15/03; G03B15/05; G03B7/00; G03B7/08; G03B7/081; G03B2215/00; G03B2215/05
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
184 words
A flash photographic system using an electronic flash unit having capacitor means to be charged with the output of an electrical power source circuit and a flash tube for emitting flash light by discharging the charge stored on said capacitor means, therethrough comprising: (a) load means to be driven by the output of said electrical power source circuit; (b) first and second capacitors constituting said capacitor means, the capacitance of said first capacitor being set to a small value compared with the capacitance of said second capacitor, and both of said capacitors being charged with the output of said electrical power source circuit; (c) inhibiting means for inhibiting said second capacitor from being charged with the output of said electrical power source circuit under the condition that the charging of said first capacitor with the output of said electrical power source circuit is maintained; and (d) drive means for driving said load means by the output of said electrical power source circuit, said inhibiting means operating to inhibit charging of said second capacitor during the time when said load operates by said drive means.
Claim 2
Dependent Claim
184 words
A flash photographic system using an electronic flash unit having capacitor means to be charged with the output of an electrical power source circuit and a flash tube for emitting flash light by discharging the charge stored on said capacitor means, therethrough comprising: (a) load means to be driven by the output of said electrical power source circuit; (b) first and second capacitors constituting said capacitor means, the capacitance of said first capacitor being set to a small value compared with the capacitance of said second capacitor, and both of said capacitors being charged with the output of said electrical power source circuit; (c) inhibiting means for inhibiting said second capacitor from being charged with the output of said electrical power source circuit under the condition that the charging of said first capacitor with the output of said electrical power source circuit is maintained; and (d) drive means for driving said load means by the output of said electrical power source circuit, said inhibiting means operating to inhibit charging of said second capacitor during the time when said load operates by said drive means.
Claim 3
Dependent Claim
45 words
A system according to claim 1, wherein said inhibiting means includes switching means arranged in a charging path between the output of said electrical power source circuit and said second capacitor, and said switching means turns off during the time when said load is driven.
Claim 4
Dependent Claim
61 words
A system according to claim 1 or 2, wherein said electronic flash unit includes voltage detecting means for detecting the voltage stored on said first capacitor upon attainment of said stored voltage to a prescribed value to produce an output, and charging control means responsive to the output of said voltage detecting means for causing said second capacitor to be charged.
Claim 5
Independent Claim
16 words
A system according to one of claims 2, wherein said load means is an electric motor.
Claim 6
Independent Claim
16 words
A system according to one of claims 2, wherein said load means is light projecting means.
Claim 7
Dependent Claim
147 words
A flash photographic system using an electronic flash unit having capacitor means to be charged with the output of a voltage boosting circuit for boosting the output of a battery and a flash tube for emitting flash light by discharging the stored voltage on said capacitor means therethrough, comprising: (a) load means to be driven by the output of said battery; (b) first and second capacitors constituting said capacitor means, the capacitance of said first capacitor being set to a small value compared with the capacitance of said second capacitor, said first capacitor being connected to said boosting circuit, and said second capacitor being connected through switching means to said boosting circuit; and (c) a drive signal forming circuit for producing a drive signal for driving said load means by the output of said battery, said switching means being turned off in response to said drive signal.
Claim 8
Dependent Claim
147 words
A flash photographic system using an electronic flash unit having capacitor means to be charged with the output of a voltage boosting circuit for boosting the output of a battery and a flash tube for emitting flash light by discharging the stored voltage on said capacitor means therethrough, comprising: (a) load means to be driven by the output of said battery; (b) first and second capacitors constituting said capacitor means, the capacitance of said first capacitor being set to a small value compared with the capacitance of said second capacitor, said first capacitor being connected to said boosting circuit, and said second capacitor being connected through switching means to said boosting circuit; and (c) a drive signal forming circuit for producing a drive signal for driving said load means by the output of said battery, said switching means being turned off in response to said drive signal.
Claim 9
Dependent Claim
100 words
A system according to claim 6, wherein said electronic flash unit includes voltage detecting means for detecting the voltage stored on said first capacitor upon attainment of said stored voltage to a prescribed value to produce an output, and said switching means operates in such a manner that it turns on in response to the output of said voltage detecting means, thereby a charging of said second capacitor is started, and, when said drive signal appears at a time during the charging, it turns off to inhibit the charging of said second capacitor for the time of driving said load.
Claim 10
Dependent Claim
103 words
A flash device comprising: (a) an electrical power source circuit (b) capacitor means including first and second capacitors, the capacitance of said first capacitor being set to a small value compared with the capacitance of said second capacitor, and both of said capacitors being charged with the output of said electrical power source circuit (c) flash tube for emitting flash light by discharging the charge stored on said capacitor means (d) inhibiting means for inhibiting said second capacitor from being charged during the time when load means to be driven by the output of said electrical power source circuit is in driven states.
Claim 11
Dependent Claim
103 words
A flash device comprising: (a) an electrical power source circuit (b) capacitor means including first and second capacitors, the capacitance of said first capacitor being set to a small value compared with the capacitance of said second capacitor, and both of said capacitors being charged with the output of said electrical power source circuit (c) flash tube for emitting flash light by discharging the charge stored on said capacitor means (d) inhibiting means for inhibiting said second capacitor from being charged during the time when load means to be driven by the output of said electrical power source circuit is in driven states.
Claim 12
Dependent Claim
47 words
A flash device according to claim 8, wherein said inhibiting means is formed by switching means, and said first capacitor is connected to an electrical power source without through said switching means while said second capacitor is connected to the electrical power source through said switching means.
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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) | 1993-03-12 | 1993-09-11 | 1994-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-12 | 1997-09-11 | 1998-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-12 | 2001-09-11 | 2002-03-13 | $7700.00 | Window Closed / Lapsed |