Patent US3727100A successfully refreshed from Google Patents.
US3727100A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic flash apparatus having control means for pre-enabling light responsive circuit means
Assignee: MORRIS 0HOTO IND Co Ltd A CORP OF JAPAN
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Filing: 1971-09-29
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Granted: 1973-04-10
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Expires: 1991-09-29
Abstract
Abstract An electronic flash apparatus including a flash tube for producing light illuminating an object to be photographed by discharge of stored voltage charge in a storage capacitor; and a light responsive integrating circuit adapted to receive light reflected from the object for generating a discharge terminating signal when a quantity of received light reaches a predetermined value, and a switching element or a quench tube for terminating the discharge across the flash tube in response to the discharge terminating signal. A delay circuit is provided for causing the light responsive integrating circuit to be ready to receive the light reflected from the object prior to the production of light by the flash tube in order to measure the light with accuracy from the instant of the production of light.
Inventors
- 👤 S Igarashi
- 👤 K Kuraishi
- 👤 N Yajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:28
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/42; G01J1/44; G01J1/46; H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; H05B41/325
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
215 words
An electronic flash apparatus comprising: a flash tube for producing light illuminating an object to be photographed; trigger circuit means connected to said flash tube for generating a trigger signal to initiate discharge across said flash tube to produce the light; light responsive integrating circuit means adapted to receive light reflected from the object to be photographed for generating a signal to terminate the discharge of said flash tube when the quantity of light reflected from the object reaches a predetermined value; switching means coupled to said flash tube; means coupled to said light responsive integrating circuit means and for controlling said switching means to terminate the discharge of said flash tube in response to said discharge terminating signal generated by said light responsive integrating circuit means; and enabling means for causing said light responsive integrating circuit means to be ready to receive the light produced by said flash tube and reflected from the object to be photographed prior to the actuation of said trigger circuit means to generate said trigger signal, said enabling means including: voltage supply means for supplying a control voltage to said trigger circuit means and a source voltage to said light responsive integrating circuit means; and delay circuit means coupled between said voltage supply means and said trigger circuit means.
Claim 2
Dependent Claim
215 words
An electronic flash apparatus comprising: a flash tube for producing light illuminating an object to be photographed; trigger circuit means connected to said flash tube for generating a trigger signal to initiate discharge across said flash tube to produce the light; light responsive integrating circuit means adapted to receive light reflected from the object to be photographed for generating a signal to terminate the discharge of said flash tube when the quantity of light reflected from the object reaches a predetermined value; switching means coupled to said flash tube; means coupled to said light responsive integrating circuit means and for controlling said switching means to terminate the discharge of said flash tube in response to said discharge terminating signal generated by said light responsive integrating circuit means; and enabling means for causing said light responsive integrating circuit means to be ready to receive the light produced by said flash tube and reflected from the object to be photographed prior to the actuation of said trigger circuit means to generate said trigger signal, said enabling means including: voltage supply means for supplying a control voltage to said trigger circuit means and a source voltage to said light responsive integrating circuit means; and delay circuit means coupled between said voltage supply means and said trigger circuit means.
Claim 3
Dependent Claim
65 words
An electronic flash apparatus according to claim 1 wherein said light responsive integrating circuit means comprises a photoelectric conversion element adapted to receive the light reflected from the object to be photographed for generating photocurrent; and an integrating capacitor connected in series with said photoelectric conversion element for producing an integration voltage proportional to the total quantity of light received by said photoelectric conversion element.
Claim 4
Dependent Claim
40 words
An electronic flash apparatus according to claim 1 wherein said voltage supply means is coupled to said delay circuit means through a normally open switch adapted to be closed by the operation of a shutter button of the associated camera.
Claim 5
Dependent Claim
23 words
An electronic flash apparatus according to claim 1 wherein said switching means includes a switching device coupled in parallel with said flash time.
Claim 6
Dependent Claim
23 words
An electronic flash apparatus according to claim 1 wherein said switching means includes a switching device coupled in series with said flash tube.
Claim 7
Dependent Claim
26 words
An electronic flash apparatus according to claim 3 including a series connection of a capacitor and a resistor coupled in parallel with said normally open switch.
Claim 8
Dependent Claim
45 words
An electronic flash apparatus according to claim 1 wherein said voltage supply means is coupled to said trigger circuit through said delay circuit means and through a normally open switch adapted to be closed by the operation of a shutter button of the associated camera.
Claim 9
Dependent Claim
26 words
An electronic flash apparatus according to claim 7 including a series connection of a capacitor and a resistor coupled in parallel with said normally open switch.
Claim 10
Dependent Claim
16 words
An electronic flash apparatus according to claim 4 wherein said switching device comprises a quench tube.
Claim 11
Dependent Claim
15 words
An electronic flash apparatus according to claim 5 wherein said switching device comprises a thyristor.
Claim 12
Dependent Claim
72 words
An electronic flash apparatus according to claim 5 wherein said switching means further comprises means responsive to said trigger for turning said switching device on so as to enable said flash tube to produce light; a secondary switching means coupled to said light responsive integrating circuit means and to said switching device for turning said switching device off responsive to said discharge terminating signal generated by said light responsive integrating circuit means.
Claim 13
Dependent Claim
16 words
An electronic flash apparatus according to claim 11 wherein said switching device comprises a first thyristor.
Claim 14
Dependent Claim
121 words
An electronic flash apparatus according to claim 12 wherein said secondary switching means includes a second thyristor coupled in series with a capacitor, the series combination of said second thyristor and said capacitor being coupled in parallel with said first thyristor; means coupling the gate electrode of said second thyristor to said light responsive integrating circuit means; and means for charging said capacitor to a predetermined level, such that when said second thyristor is turned on in response to said discharge terminating signal, he voltage across said capacitor is applied to said first thyristor in the reverse direction so as to turn said first thyristor off, thereby interrupting the discharge path for said flash tube to terminate the generation of light.
Claim 15
Dependent Claim
83 words
An electronic flash apparatus according to claim 13 wherein said means for charging said capacitor comprises a first resistance, one terminal of which is connected to the junction between said capacitor and said first thyristor, and another terminal of which is coupled to a terminal of a power source; and a second resistance, one terminal of which is coupled to the junction between said capacitor and said section thyristor, and another terminal of which is coupled to another terminal of a power source.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |