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EP0488516A2
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Method and apparatus for displaying gray-scale levels
Assignee: International Business Machines Corp
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Filing: 1991-10-22
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Granted: —
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Expires: 2011-10-22
Abstract
Abstract A liquid crystal matrix display has plural picture elements (PELs) arranged in an X-Y matrix. Each PEL includes a thin film transistor (TFT) and a display electrode. Data lines are formed in the X direction and gate lines in the Y direction. To display one of eight gray-scale levels for each PEL, one of eight voltage levels is selectively applied to the data line. The voltage levels are applied through a combination of switches which operate under the control of a selector which translates a three bit address into the selection of one or more switches. By this means the number of voltage sources and switches to operate a cell is less than the number of gray-scale values.
Inventors
- 👤 Terazawa Sadahiro
- 👤 Yamaguchi Hidefumi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 20:59
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/2007; G09G3/2011; G09G3/34; G09G3/36; G09G3/3611; G09G3/3685; G09G3/3688; G09G2310/00; G09G2310/02; G09G2310/0264; G09G2310/027
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
115 words
A method for operating a matrix display device having cells which display a range of gray-scale levels, plural voltage sources and plural switches for selecting said voltage sources to apply drive voltages to the cells in accordance with the gray-scale levels, the method comprising applying the drive voltages through switches which are selected by a selector which translates each gray-scale selection into a selection of one or a combination of the switches, each selection of one or more switches, presenting a drive voltage different from that presented by every other selection whereby the number of voltage sources and switches to operate a cell is less than the number of gray scale values for the cell.
Claim 2
Dependent Claim
107 words
A matrix display device having cells which display a range of gray-scale levels, plural voltage sources and plural switches for selecting said voltage sources to apply drive voltages to the cells in accordance with the gray-scale levels, the display device incorporating a selector to translate each gray-scale selection for a cell into a selection of one or a combination of the switches, each selection of one or more switches presenting a drive voltage different from that presented by every other selection of the switches whereby the number of voltage sources and switches to operate a cell is less than the number of gray-scale values for the cell.
Claim 3
Independent Claim
42 words
A device for displaying gray-scale levels according to claim (2), wherein the number of said plural gray-scale levels is K (where K is an integer greater than or equal to 2) and the number of said plural voltage is K/2 + 1.
Claim 4
Independent Claim
29 words
A device for displaying gray-scale levels according the claim (2) or (3) wherein the number of said plural switches is the same as the number of said voltage sources.
Claim 5
Independent Claim
18 words
A device for displaying gray-scale levels according to claim (3) or (4) wherein said switches are analog switches.
Claim 6
Independent Claim
27 words
A device for displaying gray-scale levels according to claim (2), (3), (4) or (5) wherein each drive voltage is applied to a data line of each cell.
Claim 7
Independent Claim
39 words
A device for displaying gray-scale levels according to any one of claims (2) to (6) wherein two switches can be selected to be turned on simultaneously, in accordance with a predetermined value of low-order bits of said input data.
Claim 8
Independent Claim
24 words
A device for displaying gray-scale levels according to any one of claims (2) to (7) wherein said display device is a liquid crystal device.
References Cited (Backward Citations)
No citation records indexed.
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