US3585442A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flashlamp circuit having automatic light termination means
Assignee: Rollei Werke Franke und Heidecke GmbH and Co KG
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Filing: 1969-01-27
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Granted: 1971-06-15
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Expires: 1989-01-27
Abstract
Abstract A flash tube has its flash extinguished by operation of a quench tube or switch tube which, when operated, short circuits the flash tube. The quench tube is set into operation (to stop the flash of the flash tube) by photoelectric measuring means responsive to the light reflected from the subject being photographed, when such reflected light reaches a threshold value. To avoid undesired short circuiting by operation of the quench tube as a result of light originating at some other flash apparatus located nearby, rather than the flash apparatus which the photographer desires to use, the circuit for igniting the quench tube is interconnected to the circuit of the flash tube so that the quench tube cannot be ignited except while the flash tube is flashing. This avoids undesired short circuiting discharge of the capacitor which powers the flash of the flash tube.
Inventors
- 👤 Achim Krusch
- 👤 Horst Rohman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:53
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; H05B41/325
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
196 words
Flashlamp apparatus comprising flash tube, a storage capacitor for storing energy to sustain a flash in said flash tube, means for initiating a flash in said flash tube, short circuiting means operatively connected in parallel with said flash tube and serving, when actuated, to discharge said capacitor and terminate any flash then in progress in said flash tube, light measuring means responsive to light received from a subject for generating a measuring impulse when the received light reaches an adjustable threshold value, said impulse when reaching said short circuiting means serving to actuate said short circuiting means, and switching circuit means effective to convey said measuring impulse to said short circuiting means substantially only during the time that a flash in said flash tube is in progress and to block said measuring impulse from reaching said short circuiting means at other times, said switching circuit means being normally effective to block said measuring impulse from reaching said short circuiting means and being rendered effective to convey said measuring impulse to said short circuiting means by a starting pulse when a flash is initiated in said flash tube, independently of light falling upon said switching circuit means.
Claim 2
Dependent Claim
196 words
Flashlamp apparatus comprising flash tube, a storage capacitor for storing energy to sustain a flash in said flash tube, means for initiating a flash in said flash tube, short circuiting means operatively connected in parallel with said flash tube and serving, when actuated, to discharge said capacitor and terminate any flash then in progress in said flash tube, light measuring means responsive to light received from a subject for generating a measuring impulse when the received light reaches an adjustable threshold value, said impulse when reaching said short circuiting means serving to actuate said short circuiting means, and switching circuit means effective to convey said measuring impulse to said short circuiting means substantially only during the time that a flash in said flash tube is in progress and to block said measuring impulse from reaching said short circuiting means at other times, said switching circuit means being normally effective to block said measuring impulse from reaching said short circuiting means and being rendered effective to convey said measuring impulse to said short circuiting means by a starting pulse when a flash is initiated in said flash tube, independently of light falling upon said switching circuit means.
Claim 3
Dependent Claim
58 words
A construction as defined in claim 1, wherein said short circuiting means includes a quench tube connected in parallel with said flash tube and having lower impedance than said flash tube, and quench tube firing means operated by an incoming measuring impulse to fire the quench tube to short circuit the flash tube and discharge said storage capacitor.
Claim 4
Dependent Claim
31 words
A construction as defined in claim 1, further including transformer means for initiating a flash in said flash tube, said switching circuit means being responsive to operation of said transformer means.
Claim 5
Dependent Claim
24 words
A construction as defined in claim 1, wherein said switching circuit means includes a transistor (17 or 26) controlled by a flip-flop (15, 16).
Claim 6
Dependent Claim
18 words
A construction as defined in claim 1, wherein said switching circuit means is controlled by said storage capacitor.
Claim 7
Dependent Claim
50 words
Apparatus as defined in claim 1, wherein said means for initiating a flash includes a transformer having a low voltage circuit and a high voltage circuit, and Wherein said switching circuit means is connected to and the starting pulse thereof is derived from the high voltage circuit of said transformer.
Claim 8
Dependent Claim
21 words
Apparatus as defined in claim 1, wherein the starting pulse of said switching circuit means is derived from said storage capacitor.
Claim 9
Dependent Claim
138 words
Flashlamp apparatus comprising a flash tube having a high voltage firing circuit for initiating a flash in said flash tube, a storage capacitor for storing energy to sustain a flash in said flash tube, pulse producing means responsive to incoming light for producing a pulse when the quantity of incoming light exceeds a threshold value, means responsive to a pulse for extinguishing a flash in said flash tube, a conductor for conveying a pulse from said pulse producing means to said pulse responsive means, and switching means controlled by said high voltage firing circuit for permitting a pulse to be conveyed through said conductor when said high voltage firing circuit is actuated to initiate a flash and to be conveyed a short time thereafter, and for preventing a pulse from being conveyed through said conductor at other times.
Claim 10
Dependent Claim
138 words
Flashlamp apparatus comprising a flash tube having a high voltage firing circuit for initiating a flash in said flash tube, a storage capacitor for storing energy to sustain a flash in said flash tube, pulse producing means responsive to incoming light for producing a pulse when the quantity of incoming light exceeds a threshold value, means responsive to a pulse for extinguishing a flash in said flash tube, a conductor for conveying a pulse from said pulse producing means to said pulse responsive means, and switching means controlled by said high voltage firing circuit for permitting a pulse to be conveyed through said conductor when said high voltage firing circuit is actuated to initiate a flash and to be conveyed a short time thereafter, and for preventing a pulse from being conveyed through said conductor at other times.
Claim 11
Dependent Claim
33 words
Apparatus as defined in claim 8, wherein said means for extinguishing a flash in said flash tube includes means for discharging energy remaining in said storage capacitor, otherwise than through said flash tube.
References Cited (Backward Citations)
US2892966A
Cited
US3340426A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |