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US 6,611,246 B1Granted
Liquid crystal element drive method, drive circuit, and display apparatus
AssigneeSeiko Epson Corporation
InventorsAkihiko Ito, Shoichi Iino
Life of this patent
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Abstract
A multiplex driving method and driving apparatus are provided for a liquid crystal display device having a liquid crystal layer disposed between a pair of substrates, a plurality of row electrodes arranged on one of the substrates and a plurality of column electrodes arranged on the other substrate, the plurality of row electrodes being arranged in plural groups. A portion of the row electrodes are simultaneously selected a within a selection period in which the selection period is divided into a plurality of intervals. A weighted voltage is applied in accordance with desired display data in each of the plurality of intervals to achieve a gray scale display.
Claims39
A drive method for a liquid crystal display having an array of rows and columns of pixel cells, each row of pixel cells being responsive to a corresponding row-select scanning electrode and each column of pixel cells being responsive to a corresponding column-select image data electrode, the intersection of a row-select scanning electrode and a column-select image data electrode defining the location of a corresponding pixel cell, each of said pixel cells having an adjustable gray-scale defined by a multi-bit data word, said drive method comprising:
- applying a scanning pulse-train sequence to a target row-select scanning electrode, said scanning pulse-train sequence comprising a series of logic high scanning pulses and logic low scanning pulses, dividing each scanning pulse in said scanning pulse-train sequence into k time segments where k is the number of bits in said multi-bit data word, assigning each of said k time segments a one-to-one correspondence with a data bit in said multi-bit data word;
- calculating an image data signal for each of said k time segments in each scanning pulse based on the current logic value of each time segment's corresponding scanning pulse and corresponding data bit;
- grouping the calculated image data signals of said k time segments within each scanning pulse into a corresponding composite mini-pulse-train of duration equal to said scanning pulse, whereby each composite mini-pulse-train is made to comprise k image data signals and is made to have a one-to-one correspondence with a specific scanning pulse within said scanning pulse-train sequence;
- applying to a target column-select image data electrode, the composite mini-pulse-train corresponding to each scanning pulse of said scanning pulse-train sequence currently applied to said target row-select scanning electrode.
1 more element
A drive method for a liquid crystal device comprising the steps of:
- (a) applying a scanning signal to each of a plurality of scanning electrodes comprising a selection signal during a selection period and a non-selection signal during a non-selection period;
- and
- (b) applying a data signal to each of a plurality of signal electrodes based on display data representing each pixel cell of an image having a gray scale to be displayed by the liquid crystal device, said display data comprising a plurality of bits per pixel cell;
- wherein step (a) further comprises the step of:
- (1) grouping the plurality of scanning electrodes into p groups, wherein p is an integer of at least two;
- (2) applying the selection signal substantially simultaneously to the plurality of the scanning electrodes in one of the p groups and applying the non-selection signal substantially simultaneously to the plurality of scanning electrodes in one of the p groups immediately after applying the selection signal thereto and selecting a level of the selection signal based on an orthogonal function, wherein the selection signal is sequentially applied to succeeding groups of the scanning electrodes, wherein the non-selection signal is sequentially applied to succeeding groups of the scanning electrode groups immediately after applying the selection signal thereto, and wherein the orthogonal function has information for determining a level of the selection signal;
- and
- (c) applying a weighted voltage in accordance with the display data in each of the selection periods.
5 more elements
A drive method for a liquid crystal device comprising the steps of:
- (a) applying a scanning signal to each of a plurality of scanning electrodes comprising a selection signal during a selection period and a non-selection signal during a non-selection period;
- and
- (b) applying a data signal to each of a plurality of signal electrodes based on display data representing an image having a gray scale to be displayed by the liquid crystal device, said display data comprising a plurality of bits;
- wherein step (a) further comprises the step of:
- (1) grouping the plurality of scanning electrodes into p groups, wherein p is an integer of at least two;
- (2) applying the selection signal substantially simultaneously to the plurality of the scanning electrodes in one of the p groups and applying the non-selection signal substantially simultaneously to the plurality of scanning electrodes in one of the p groups immediately after applying the selection signal thereto and selecting a level of the selection signal based on an orthogonal function, wherein the selection signal is sequentially applied to succeeding groups of the scanning electrodes, wherein the non-selection signal is sequentially applied to succeeding groups of the scanning electrode groups immediately after applying the selection signal thereto, wherein the orthogonal function has information for determining a level of the selection signal, and
- wherein the display data comprises q bits, q being a positive integer, each of the selection periods is divided into unequal k intervals in accordance with the q bits, and each of the k intervals is allocated to a corresponding one of said q bits of the display data.
4 more elements
A drive method for a liquid crystal device comprising the steps of:
- (a) applying a scanning signal to each of a plurality of scanning electrodes comprising a selection signal during a selection period and a non-selection signal during a non-selection period;
- and
- (b) applying a data signal to each of a plurality of signal electrodes based on data representing an image having a gray scale to be displayed by the liquid crystal device;
- wherein step (a) further comprises t he step of:
- (1) grouping the plurality of scanning electrodes into p groups, wherein p is an integer of at least two;
- (2) applying the selection signal substantially simultaneously to the plurality of the scanning electrodes in one of the p groups and applying the non-selection signal substantially simultaneously to the plurality of scanning electrodes in one of the p groups immediately after applying the selection signal thereto and selecting a level of the selection signal based on an orthogonal function, wherein the selection signal is sequentially applied to succeeding groups of the scanning electrodes, wherein the non-selection signal is sequentially applied to succeeding groups of the scanning electrode groups immediately after applying the selection signal thereto, wherein the orthogonal function has information for determining a level of the selection signal, wherein a single frame period is defined as a period during which all of combined selection signals to be applied to all of groups of scanning electrodes are applied, wherein a voltage applied to the signal electrodes is modulated during an interval of plural frame periods to display the image having the gray scale;
- and
- (c) applying a voltage in accordance with the display data in each of the selection periods.
5 more elements
Dependencies are inferred from the claim text.