High impedance driver for bi-stable and multi-stable displays and method to drive same
AssigneeNew Vision Display, Inc.
InventorsQuanshui Shi, Steve Beldon
Life of this patent
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Abstract
A method to drive bi-stable liquid crystal displays and related drivers and displays using same are disclosed. The method and driver use additional high impedance states of the outputs to save power while addressing bi-stable and multi-stable liquid crystal displays. The invention implements high impedance states at the driver outputs, allowing non-addressed sections of the display to electrically “float” and by doing so reduces the required power to drive the display. Other advantages include improved visual effect of an update, such as reduced flash during the update, simpler operation, and better yields due to a larger operating window.
Claims22
A method of addressing a passive matrix liquid crystal display comprising:
- providing a plurality of pixels, wherein the plurality of pixels is arranged into a plurality of rows and a plurality of columns to form an array, and wherein each pixel in the plurality of pixels comprises a plurality of liquid crystal molecules, and wherein an electric signal applied to one of the plurality of rows and one of the plurality of columns creates an electric field across plurality of liquid crystal molecules of each pixel in the plurality of pixels at an intersection of the one of the plurality of rows and the one of the plurality of columns;
- providing a row driver comprising a plurality of row outputs;
- providing a column driver comprising a plurality of column outputs;
- outputting a row signal on at least one of the plurality of row outputs;
- outputting a column signal on at least one of the plurality of column outputs;
- driving a target image using the row signal and the column signal;
- setting at least one of the plurality of row outputs or at least one of the plurality of column outputs to a high impedance state wherein when the at least one of the plurality of row outputs is in the high impedance state, the at least one of the plurality of row outputs is isolated from the row driver and when the at least one of the plurality of column outputs is in the high impedance state, the at least one of the plurality of column outputs is isolated from the column driver;
- and
- addressing the passive matrix liquid crystal display by applying a voltage to at least one of the plurality of pixels within the array.
A low power passive matrix liquid crystal display comprising:
- a plurality of pixels, wherein:
- the plurality of pixels is arranged into a plurality of rows and a plurality of columns to form an array;
- each pixel in the plurality of pixels comprises a plurality of liquid crystal molecules, and
- an electric signal applied to one of the plurality of rows and one of the plurality of columns creates an electric field across plurality of liquid crystal molecules of each pixel in the plurality of pixels at an intersection of the one of the plurality of rows and the one of the plurality of columns;
- a row driver comprising a plurality of row outputs, wherein the row driver outputs a row signal on at least one of the plurality of row outputs;
- a column driver comprising a plurality of column outputs, wherein the column driver outputs a column signal on at least one of the plurality of column outputs;
- wherein at least one of the plurality of row outputs or one of the plurality of column outputs assumes a high impedance state while applying a voltage to at least one of the plurality of pixels within the array to address the low power passive matrix liquid crystal display;
- and
- wherein when the at least one of the plurality of row outputs is in the high impedance state, the at least one of the plurality of row outputs is isolated from the row driver and when the at least one of the plurality of column outputs is in the high impedance state, the at least one of the plurality of column outputs is isolated from the column driver.
A liquid crystal display driver for a passive matrix liquid crystal display comprising:
- a row driver comprising a plurality of row outputs;
- a column driver comprising a plurality of column outputs;
- wherein at least one of the plurality of row outputs or one of the plurality of column outputs assumes a high impedance state while addressing a low power passive matrix liquid crystal display;
- and
- wherein when the at least one of the plurality of row outputs is in the high impedance state, the at least one of the plurality of row outputs is isolated from the row driver and when the at least one of the plurality of column outputs is in the high impedance state, the at least one of the plurality of column outputs is isolated from the column driver.
Dependencies are inferred from the claim text.