US3586906A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuit for photoflash discharge lamps
Assignee: Nikon Corp
•
Filing: 1969-02-07
•
Granted: 1971-06-22
•
Expires: 1989-02-07
Abstract
Abstract Photoflash discharge lamps are controlled by a circuit which employs a glow tube operable in connection with the terminal voltage of a condenser, which stores energy from a source of voltage. The voltage source is interruptable by an intermittent current due to the flashing of the glow tube. A monitor circuit is provided which is driven by the discharge current of the glow tube to negatively control the terminal voltage of the glow tube and control the ratio of the voltage at the beginning of discharge to the voltage at the termination of discharge. As a result, the terminal voltage of the condenser is maintained substantially constant.
Inventors
- 👤 Keno Okuno
- 👤 Kouichi Takahata
- 👤 Takeshi Suda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:52
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
115 words
Electronic photoflash apparatus comprising a DC voltage source, a condenser connected to the voltage source, the condenser being adapted to have a photoflash discharge lamp connected thereto, and a monitor circuit for controlling the terminal voltage of the condenser including a potentiometer connected in parallel with the main condenser, a glow tube actuated in accordance with the terminal voltage of the condenser through the potentiometer, means for dropping the voltage of the glow tube to near its discharge termination voltage when the glow tube begins its discharge, and switching means actuated by the glow tube for periodically terminating the supply of energy from the voltage source to the condenser while the glow tube is discharging.
Claim 2
Dependent Claim
115 words
Electronic photoflash apparatus comprising a DC voltage source, a condenser connected to the voltage source, the condenser being adapted to have a photoflash discharge lamp connected thereto, and a monitor circuit for controlling the terminal voltage of the condenser including a potentiometer connected in parallel with the main condenser, a glow tube actuated in accordance with the terminal voltage of the condenser through the potentiometer, means for dropping the voltage of the glow tube to near its discharge termination voltage when the glow tube begins its discharge, and switching means actuated by the glow tube for periodically terminating the supply of energy from the voltage source to the condenser while the glow tube is discharging.
Claim 3
Dependent Claim
43 words
Electronic photoflash apparatus according to claim 1, wherein the means for dropping the voltage of the glow tube includes a transistor the base of which is connected to the glow tube, the collector to the potentiometer, and the emitter to the switching device.
Claim 4
Dependent Claim
27 words
Electronic photoflash apparatus according to claim 2, wherein the potentiometer has two adjustable contacts connected to the glow tube and to the collector of the transistor, respectively.
Claim 5
Dependent Claim
41 words
Electronic photoflash apparatus according to claim 2, further comprising a DC-DC converter for raising the voltage of the voltage source; and wherein the switching means acts to periodically terminate the oscillation of the DC-DC converter while the glow tube is discharging.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |