Patent US3754162A successfully refreshed from Google Patents.
US3754162A
Expired / Lapsed
US
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Photoflash network
Assignee: Sunpak KK
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Filing: 1971-03-03
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Granted: 1973-08-21
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Expires: 1991-03-03
Abstract
Abstract A variable duration photoflash network includes a gas discharge flash tube connected through an SCR to a charge capacitor and a transformer simultaneously applies a triggering signal to the SCR gate and the flash tube trigger electrode. A timing network includes an RC circuit whose resistor is a photoconductor and is initiated and energized with the ignition of the flash tube by the voltage developed across an inductor in series with the flashtube, which voltage charges a capacitor through a rectifier. The RC timing capacitor after the timed interval effects the triggering of an SCR which connects a voltage source across the first SCR in series opposition with the charge capacitor to open the first SCR and extinguish the flash tube.
Inventors
- 👤 M Katayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:16
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; H05B41/325
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
168 words
An electronic flash network comprising a gas discharge flash tube including a triggering electrode, a first current source, first means for connecting said gas discharge tube to said first current source and including a gated electronic first switch having output electrodes connected between said discharge tube and said first current source and a gate electrode, a timing network, second means for substantially simultaneously actuating said timing network and applying triggering signals to said gate and triggering electrode to fire said photoflash tube, and third means responsive to said timing network for applying a reverse voltage cut-off signal between said switch output electrodes to open said switch and extinguish said photoflash tube discharge and characterized in that said second means comprises a second current source, a transformer including a primary winding and a first secondary winding connected to said switch gate electrode and a second secondary winding connected to said flash tube triggering electrode, and means including a switch for connecting said primary winding to said second current source.
Claim 2
Dependent Claim
168 words
An electronic flash network comprising a gas discharge flash tube including a triggering electrode, a first current source, first means for connecting said gas discharge tube to said first current source and including a gated electronic first switch having output electrodes connected between said discharge tube and said first current source and a gate electrode, a timing network, second means for substantially simultaneously actuating said timing network and applying triggering signals to said gate and triggering electrode to fire said photoflash tube, and third means responsive to said timing network for applying a reverse voltage cut-off signal between said switch output electrodes to open said switch and extinguish said photoflash tube discharge and characterized in that said second means comprises a second current source, a transformer including a primary winding and a first secondary winding connected to said switch gate electrode and a second secondary winding connected to said flash tube triggering electrode, and means including a switch for connecting said primary winding to said second current source.
Claim 3
Dependent Claim
23 words
The electronic flash network of claim 1 wherein said timing network comprises an RC timing circuit including a resistance element and a capacitor.
Claim 4
Dependent Claim
23 words
The electronic flash network of claim 2 wherein said RC resistance element is adjustable to vary the time constant of said RC circuit.
Claim 5
Dependent Claim
34 words
The electronic flash network of claim 2 wherein said RC resistance element comprises a photosensitive device whose resistance varies with the light incident thereon whereby to vary the time constant of said RC circuit.
Claim 6
Dependent Claim
43 words
The flash network of claim 1 wherein said electronic switch comprises a gated solid state switch, said cut-off signal being a pulse signal applied across said device output electrode in a direction opposite to that of the direction of the conduction current therein.
Claim 7
Dependent Claim
62 words
The network of claim 1 wherein said third means comprises a third current source, a solid state second switch including a control electrode, means series connecting said first and third current sources, in opposition, and said second switch across said first switch output electrodes, and means responsive to said timing network for applying a triggering signal to said second switch control electrode.
Claim 8
Dependent Claim
49 words
The network of claim 6 wherein said first, second and third current sources comprise first, second and third capacitors respectively and comprising means including a resistor for connecting said first capacitor across said first capacitor and means including a diode for connecting said third capacitor across said first capacitor.
Claim 9
Dependent Claim
150 words
An electronic flash network comprising a gas discharge flash tube including a triggering electrode, a first current source, first means for connecting said gas discharge tube to said first current source and including a gated electronic first switch having output electrodes connected between said discharge tube and said first current source and a gate electrode, a timing network, second means for substantially simultaneously actuating said timing network and applying triggering signals to said gate and triggering electrode to fire said photoflash tube, and third means responsive to said timing network for applying a reverse voltage cut-off signal between said switch output electrodes to open said switch and extinguish said photoflash tuBe discharge, said second means comprising an inductor connected in series between said flash tube and said first current source, and means for energizing said timing network including a capacitor and a rectifying device connecting said capacitor across said inductor.
Claim 10
Dependent Claim
150 words
An electronic flash network comprising a gas discharge flash tube including a triggering electrode, a first current source, first means for connecting said gas discharge tube to said first current source and including a gated electronic first switch having output electrodes connected between said discharge tube and said first current source and a gate electrode, a timing network, second means for substantially simultaneously actuating said timing network and applying triggering signals to said gate and triggering electrode to fire said photoflash tube, and third means responsive to said timing network for applying a reverse voltage cut-off signal between said switch output electrodes to open said switch and extinguish said photoflash tuBe discharge, said second means comprising an inductor connected in series between said flash tube and said first current source, and means for energizing said timing network including a capacitor and a rectifying device connecting said capacitor across said inductor.
Claim 11
Dependent Claim
172 words
An electronic flash network comprising a gas discharge flash tube including a triggering electrode, a first current source, first means for connecting said gas discharge tube to said first current source and including a gated electronic first switch having output electrodes connected between said discharge tube and said first current source and a gate electrode, a timing network, second means for substantially simultaneously actuating said timing network and applying triggering signals to said gate and triggering electrode to fire said photoflash tube, and third means responsive to said timing network for applying a reverse voltage cut-off signal between said switch output electrodes to open said switch and extinguish said photoflash tube discharge and characterized in that said third means comprises a third current source, a solid state second switch including a control electrode, means series connecting said first and third current sources, in opposition, and said second switch across said first switch output electrodes, and means responsive to said timing network for applying a triggering signal to said second switch control electrode.
Claim 12
Dependent Claim
172 words
An electronic flash network comprising a gas discharge flash tube including a triggering electrode, a first current source, first means for connecting said gas discharge tube to said first current source and including a gated electronic first switch having output electrodes connected between said discharge tube and said first current source and a gate electrode, a timing network, second means for substantially simultaneously actuating said timing network and applying triggering signals to said gate and triggering electrode to fire said photoflash tube, and third means responsive to said timing network for applying a reverse voltage cut-off signal between said switch output electrodes to open said switch and extinguish said photoflash tube discharge and characterized in that said third means comprises a third current source, a solid state second switch including a control electrode, means series connecting said first and third current sources, in opposition, and said second switch across said first switch output electrodes, and means responsive to said timing network for applying a triggering signal to said second switch control electrode.
Claim 13
Dependent Claim
49 words
The network of claim 9 wherein said first, second and third current sources comprise first, second and third capacitors respectively and comprising means including a resistor for connecting said first capacitor across said first capacitor and means including a diode for connecting said third capacitor across said first capacitor.
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) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |