Electro-optic displays, and methods for driving same
First Claim
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1. A method of driving an electro-optic display, the electro-optic display comprising:
- a layer of an electro-optic medium;
a plurality of pixel electrodes disposed on one side of the layer of electro-optic medium and arranged in a two-dimensional array of rows and columns, each of the pixel electrodes being capable of applying an electric field to the electro-optic medium;
a plurality of column electrodes, each column electrode being associated with the pixel electrodes in one column of the two-dimensional array; and
a front electrode provided on the opposed side of the layer of electro-optic medium from the pixel electrodes,the method comprising changing the voltage on one column electrode from a first value to a second value different from the first value, thereby causing at least one pixel electrode to cause a change in optical state of the electro-optic medium, wherein the voltage on said one column electrode is first changed from the first value to a third value intermediate the first and second values for a period sufficient to permit charge to flow to or from said one column electrode, and thereafter the voltage on said one column electrode is changed from the third value to the second value.
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Abstract
An electro-optic display includes an electro-optic medium, a pixel electrode for applying an electric field to the medium and a column electrode associated with the pixel electrode. To reduce power consumption, when it is necessary to change the voltage on the column electrode from a first value to a second value to change the optical state of the electro-optic medium, the column electrode voltage is first changed to a third value intermediate the first and second values to permit charge to flow to or from the column electrode, and thereafter the column electrode voltage is changed from the third voltage to the second voltage.
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Citations
24 Claims
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1. A method of driving an electro-optic display, the electro-optic display comprising:
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a layer of an electro-optic medium; a plurality of pixel electrodes disposed on one side of the layer of electro-optic medium and arranged in a two-dimensional array of rows and columns, each of the pixel electrodes being capable of applying an electric field to the electro-optic medium; a plurality of column electrodes, each column electrode being associated with the pixel electrodes in one column of the two-dimensional array; and a front electrode provided on the opposed side of the layer of electro-optic medium from the pixel electrodes, the method comprising changing the voltage on one column electrode from a first value to a second value different from the first value, thereby causing at least one pixel electrode to cause a change in optical state of the electro-optic medium, wherein the voltage on said one column electrode is first changed from the first value to a third value intermediate the first and second values for a period sufficient to permit charge to flow to or from said one column electrode, and thereafter the voltage on said one column electrode is changed from the third value to the second value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for driving an electro-optic display, the electro-optic display comprising:
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a layer of an electro-optic medium; a plurality of pixel electrodes disposed on one side of the layer of electro-optic medium and arranged in a two-dimensional array of rows and columns, each of the pixel electrodes being capable of applying an electric field to the electro-optic medium; a plurality of column electrodes, each column electrode being associated with the pixel electrodes in one column of the two-dimensional array; and a front electrode provided on the opposed side of the layer of electro-optic medium from the pixel electrodes, the apparatus comprising; a column driver capable of applying at least first, second and third voltages to each of the column electrodes, the first and second voltages differing from each other and the third voltage being intermediate the first and second voltages; and logic means arranged to determine, for each of the column electrodes, when the column driver needs to change the voltage applied to a selected column electrode from the first voltage to the second voltage, and, when the need for such a change is detected, to cause the column driver to first apply the third voltage to the selected column electrode for a period sufficient to permit charge to flow to or from the selected column electrode, and thereafter to case the column driver to apply the second voltage to the selected column electrode. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification