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US 7,064,737 B2Granted
Method of driving cholesteric liquid crystal display panel using root-mean-square voltage
AssigneeSamsung SDI Co., Ltd.
InventorsNam-Seok Lee, Woon-Seop Choi, Yeon-Gon Mo, Ki-Suk Seong, Seok-Hong Jeong
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Abstract
A method of driving a cholesteric liquid crystal display (LCD) panel by applying at least first, second, and third voltages to cholesteric liquid crystal cells of the cholesteric LCD panel is provided. The method includes alternately applying the first and second voltages to apply the third voltage, which is given by the root-mean-square value of the first and second voltages, to the cholesteric liquid crystal cells.
Claims19
A method of driving a cholesteric liquid crystal display panel, the method comprising:
- applying in a preparation step a first voltage to all cholesteric liquid crystal cells of said cholesteric liquid crystal display panel accommodating all cholesteric liquid crystal cells changing into a homeotropic state;
- applying in a selection step a second voltage lower than said first voltage to cholesteric liquid crystal cells that are turned on to accommodate the turned on cholesteric liquid crystal cells maintaining said homeotropic state, and a third voltage lower than said second voltage being applied to cholesteric liquid crystal cells that are turned off to accommodate the turned off cholesteric liquid crystal cells changing into a transient-planar state;
- applying in an evolution step a fourth voltage, being lower than said first voltage and higher than said second voltage, to all cholesteric liquid crystal cells to accommodate said cholesteric liquid crystal cells that are turned on maintaining said homeotropic state, and said cholesteric liquid crystal cells that are turned off changing into a focal conic state, said first and second voltages being alternately applied in said evolution step to apply said fourth voltage, being given by a root-mean-square value of said first and second voltages, to all cholesteric liquid crystal cells;
- and
- applying said third voltage in a maintenance step to all cholesteric liquid crystal cells to accommodate said cholesteric liquid crystal cells that are turned on to change into a planar state, and said cholesteric liquid crystal cells that are turned off maintaining said focal conic state.
2 more elements
A method, comprising:
- applying a first voltage to a liquid crystal display to change all of a plurality of liquid crystal cells of said liquid crystal display into a homeotropic state;
- applying a second voltage to said liquid crystal cells that are turned on to accommodate the turned on liquid crystal cells maintaining said homeotropic state, and a third voltage lower than said second voltage being applied to liquid crystal cells that are turned off to accommodate the turned off liquid crystal cells changing into a transient-planar state, said second voltage being lower than said first voltage;
- and
- applying said first and second voltages alternately over a first period of time to all liquid crystal cells to accommodate said cholesteric liquid crystal cells that are turned on maintaining said homeotropic state, and said cholesteric liquid crystal cells that are turned off changing into a focal conic state.
1 more element
Dependencies are inferred from the claim text.