US3689770A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure control circuit for an electrically shuttered image tube
Assignee: Government of the United States of America
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Filing: 1971-07-28
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Granted: 1972-09-05
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Expires: 1991-07-28
Abstract
Abstract In order to maintain an optimum image under varying light conditions for an electrically shuttered image tube, it is necessary to control the time that the electronic shutter is open. This is done in the instant disclosure by detecting the amount of photocathode current that flows after the shutter is opened, and closing the shutter when a predetermined amount of current has flowed.
Inventors
- 👤 Donald F Dion
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:54
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/70; H04N23/73
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
67 words
A system for electronically shuttering an image tube, wherein said tube includes a photocathode for providing a current related to light level when said photocathode is energized including: voltage means; relay means for connecting said voltage means to said photocathode; current sensing means connected to said photocathode; a trigger having an input connected to said current sensing means and having an output connected to said relay means.
Claim 2
Independent Claim
67 words
A system for electronically shuttering an image tube, wherein said tube includes a photocathode for providing a current related to light level when said photocathode is energized including: voltage means; relay means for connecting said voltage means to said photocathode; current sensing means connected to said photocathode; a trigger having an input connected to said current sensing means and having an output connected to said relay means.
Claim 3
Dependent Claim
77 words
The system as defined in claim 1 wherein said current sensing means includes a commutator having an output, and having an input connected to said photocathode; an a-c amplifier having an output, and having an input connected to said output of said commutator; an integrator having an input and having an output connected to said input of said trigger; and a fullwave rectifier connected between said output of said a-c amplifier and aid input of said integrator.
References Cited (Backward Citations)
US2976758A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-05 | 1976-03-06 | 1976-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-05 | 1980-03-06 | 1980-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-05 | 1984-03-06 | 1984-09-05 | $7700.00 | Window Closed / Lapsed |