US3882359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for stabilizing the brilliancy of an oscilloscope
Assignee: LANNIONNAIS ELECTRONIQUE
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Filing: 1973-06-11
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Granted: 1975-05-06
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Expires: 1993-06-11
Abstract
Abstract A device for stabilizing the brightness of an oscilloscope including a differential circuit with two photo-transistors, only one of which is positioned to receive illumination from the screen of the oscilloscope. In this way a contrast may be obtained which remains identical for a period of time having any desired duration.
Inventors
- 👤 Fernand Secher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:34
CPC Classifications
G; G01; G01R; G01R13/00; G01R13/20; G01R13/22; G01R13/26
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
233 words
A device for the stabilization of the brightness of a display device, including a cathode ray tube having a brightness control input and a screen, a time base means for controlling the timing of operation of said cathode ray tube, comprising a first differential amplifier having two inputs, a first photo-transistor disposed before the screen of said cathode ray tube so as to receive illumination therefrom and being connected to one input of said first differential amplifier, a second photo-transistor disposed at a position isolated from the illumination of the screen of said cathode ray tube and being connected to a second input of said first differential amplifier, a second differential amplifier having two inputs, one input being connected to the output of said first differential amplifier anD the other input being connected to a source of reference potential, control voltage generating means responsive to the output of said second differential amplifier for generating a control voltage which increases in a step-wise manner until the output of said first differential amplifier reaches the level of said reference potential as indicated by the output of said second differential amplifier, and an adder amplifier having one input connected to the output of said control voltage generating means and another input connected to a source of video signals, the output of said adder amplifier being connected to said brightness control input of said cathode ray tube.
Claim 2
Independent Claim
233 words
A device for the stabilization of the brightness of a display device, including a cathode ray tube having a brightness control input and a screen, a time base means for controlling the timing of operation of said cathode ray tube, comprising a first differential amplifier having two inputs, a first photo-transistor disposed before the screen of said cathode ray tube so as to receive illumination therefrom and being connected to one input of said first differential amplifier, a second photo-transistor disposed at a position isolated from the illumination of the screen of said cathode ray tube and being connected to a second input of said first differential amplifier, a second differential amplifier having two inputs, one input being connected to the output of said first differential amplifier anD the other input being connected to a source of reference potential, control voltage generating means responsive to the output of said second differential amplifier for generating a control voltage which increases in a step-wise manner until the output of said first differential amplifier reaches the level of said reference potential as indicated by the output of said second differential amplifier, and an adder amplifier having one input connected to the output of said control voltage generating means and another input connected to a source of video signals, the output of said adder amplifier being connected to said brightness control input of said cathode ray tube.
Claim 3
Dependent Claim
58 words
A device as defined in claim 1, wherein said one input of said second differential amplifier is connected to the output of said first differential amplifier by way of a resistance network and the other input of said second differential amplifier is also connected to the output of said first differential amplifier through a low pass filter network.
Claim 4
Dependent Claim
120 words
A device according to claim 2, wherein said control voltage generating means comprises a bistable memory device connected to be reset to zero by the output of said second differential amplifier, a clock pulse generator, a pulse counter, a monostable multivibrator, and an associated numerical-analog converter whose output is connected to said one input of said adder amplifier, a first AND gate having one input connected to the output of said pulse generator, a second input connected to the output of said bistable memory device and a third input connected to the output of said monostable multivibrator, differentiating circuit means connected to the output of said monostable multivibrator for setting said bistable memory device and resetting said counter to zero.
Claim 5
Dependent Claim
45 words
A device according to claim 3, wherein said bistable memory device is reset to zero by the state of full capacity of said pulse counter by means of a second AND gate connected between the output of said pulse counter and said bistable memory device.
Claim 6
Dependent Claim
80 words
A device according to claim 2, wherein said control voltage generating means comprises a charge capacitor, a current source, a bistable memory device connected to be reset to zero by the output of said second differential amplifier, analog gate means connected to said current source and said capacitor for passing or interrupting the charging current to the capacitor according to the state of said bistable memory device, and means for discharging said capacitor at the begining of a regulating period.
Claim 7
Dependent Claim
31 words
A device according to claim 2, further including means for disconnecting said time base from said cathode ray tube and the video signal from said adder amplifier during the regulating period.
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) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |