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US3778673A
Expired / Lapsed
US
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Low power display driver having brightness control
Assignee: Unisys Corp
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Filing: 1971-06-21
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Granted: 1973-12-11
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Expires: 1991-06-21
Abstract
Abstract Low power drive apparatus connected for operating display devices including a plurality of gas-filled cells and gas communication channels extending between adjacent columns of cells for scanning of them by glow transfer from column to column. The driving apparatus includes series-connected drive circuits for the display control anodes of the devices, operated in the current-controlling mode of the input data signals. The display anode drivers are connected as controllable current sources which do not saturate when activated. A variable voltage device is connected to the current drivers for controlling the brightness of the display by regulating the amount of current conducted to the display cells when activated.
Inventors
- 👤 M Eisenberg
- 👤 G Holz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:58
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/12; H04N3/125; G; G09; G09G; G09G3/00; G09G3/20; G09G3/22; G09G3/28; G09G3/282; G09G3/285; H01; H01J; H01J17/00; H01J17/38; H01J17/48; H01J17/49; H01J17/492; H01J17/494
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
114 words
Low power drive apparatus for display devices having an array of gas-filled display cells interconnected in groups and a plurality of energizing electrodes and a plurality of display control electrodes disposed in contact with the gas in different groups of the cells and extending out of the cells, said apparatus comprising a plurality of unidirectional constant current drivers coupled to a common potential terminal, each including a resistance connected in series with one of the display control electrodes to control ionization in the cells selectively at a predetermined current in the cells and each having a control terminal to activate the driver upon receiving input signals for data to be displayed by the device.
Claim 2
Dependent Claim
114 words
Low power drive apparatus for display devices having an array of gas-filled display cells interconnected in groups and a plurality of energizing electrodes and a plurality of display control electrodes disposed in contact with the gas in different groups of the cells and extending out of the cells, said apparatus comprising a plurality of unidirectional constant current drivers coupled to a common potential terminal, each including a resistance connected in series with one of the display control electrodes to control ionization in the cells selectively at a predetermined current in the cells and each having a control terminal to activate the driver upon receiving input signals for data to be displayed by the device.
Claim 3
Dependent Claim
47 words
The low power drive apparatus for display devices of claim 1 wherein the constant current drivers comprise a plurality of common-emitter connected transistors coupled between the common potential terminal and the corresponding display control electrodes, with their base electrodes being connected as the control terminals for them.
Claim 4
Dependent Claim
54 words
The low power drive apparatus for display devices of claim 2 further comprising a variable voltage gate having a control terminal and being connected to the common potential terminal for determining the amount of current that the current drivers conduct when activated by the input data signals to control the brightness of the display.
Claim 5
Dependent Claim
50 words
The low power drive apparatus for display devices of claim 1 wherein the constant current drivers comprise a plurality of common-base coNnected transistors having their base electrodes coupled to the common potential terminal, their collectors coupled to the corresponding display control electrodes and their emitters connected as the control terminals.
Claim 6
Dependent Claim
54 words
The low power drive apparatus for display devices of claim 11 further comprising a variable voltage gate having a control terminal and being connected to the common potential terminal for determining the amount of current that the current drivers conduct when activated by the input data signals to control the brightness of the display.
Claim 7
Dependent Claim
47 words
The drive apparatus for display devices of claim 5 wherein the variable voltage gate comprises a transistor operated in the active region and having its base-emitter circuit connected between a variable voltage device and the common potential terminal and its collector connected to a reference potential terminal.
Claim 8
Dependent Claim
42 words
The drive apparatus for display devices of claim 6 wherein the base-emitter circuit of the variable voltage gate transistor further comprises means for receiving blanking control signals for control of the display current drivers and the variable voltage device comprises a potentiometer.
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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |