Methods for reducing edge effects in electro-optic displays
AssigneeE Ink Corporation
InventorsRobert W. Zehner, Karl R. Amundson
Life of this patent
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Abstract
Edge effects in electro-optic displays are reduced by (a) ensuring that during rewriting of the display, the last period of non-zero voltage applied all pixels terminates at substantially the same time; and (b) scanning the display at a scan rate of at least 50 Hz.
Claims31
A method of driving an electro-optic display having a plurality of pixels each of which is capable of displaying at least three gray levels, the method comprising:
- displaying a first image on the display;
- and
- rewriting the display to display a second image thereon by applying to each pixel a waveform effective to cause the pixel to change from an initial gray level to a final gray level,
- wherein, for all pixels undergoing non-zero transitions, the waveforms applied to the pixels have their last period of non-zero voltage terminating at substantially the same time;
- and
- wherein at least one pixel undergoes a zero transition during which there is applied to that pixel at least one period of non-zero voltage, and wherein the last period of non-zero voltage applied to the pixel undergoing the zero transition terminates at substantially the same time as the last period of non-zero voltage applied to the pixels undergoing a non-zero transition.
An electro-optic display having a plurality of pixels, each of which is capable of displaying at least three gray levels, at least one pixel electrode being associated with each pixel and capable of applying an electric field thereto, and drive means for applying waveforms to the pixel electrodes, the drive means being arranged so that, for all pixels undergoing non-zero transitions, the waveforms applied to the pixels have their last period of non-zero voltage terminating at substantially the same time;
- and wherein for all pixels undergoing zero transitions during which there is applied to that pixel at least one period of non-zero voltage, the last period of non-zero voltage applied to the pixel undergoing the zero transition terminates at substantially the same time as the last period of non-zero voltage applied to the pixels undergoing a non-zero transition.
A method of driving an electro-optic display having a plurality of pixels each of which is capable of displaying at least three gray levels, the method comprising:
- displaying a first image on the display;
- and
- rewriting the display to display a second image thereon by applying to each pixel a waveform effective to cause the pixel to change from an initial gray level to a final gray level,
- wherein, for all pixels undergoing non-zero transitions, the waveforms applied to the pixels have their last period of non-zero voltage beginning at substantially the same time;
- and
- wherein at least one pixel undergoes a zero transition during which there is applied to that pixel at least one period of non-zero voltage, and wherein the last period of non-zero voltage applied to the pixel undergoing the zero transition terminates at substantially the same time as the last period of non-zero voltage applied to the pixels undergoing a non-zero transition.
A method of driving an electro-optic display having a plurality of pixels each of which is capable of displaying at least three gray levels, the method comprising:
- displaying a first image on the display;
- and
- rewriting the display to display a second image thereon by applying to each pixel a waveform effective to cause the pixel to change from an initial gray level to a final gray level,
- wherein, for all pixels undergoing non-zero transitions, the waveforms applied to the pixels have at least one voltage transition occurring at substantially the same time in each waveform, the waveforms for all pixels undergoing non-zero transitions being of the form −x/ΔIP/x, where ΔIP denotes a difference in impulse potential between the final and initial states of the waveform, while −x and x represent a DC balanced pair of pulses.
Dependencies are inferred from the claim text.