Apparatus and methods for pulsing the electrodes of an electrophoretic display for achieving faster display operation
First Claim
1. Apparatus for driving an electrophoretic display in a write mode, which display is of the type having a plurality of grid lines insulated from a plurality of cathode lines with said grid and cathode lines positioned perpendicular to one another to provide an X-Y matrix, and said display having an anode electrode, said display enabling a picture to be displayed on said cathode by selectively accessing intersecting grid and cathode lines each indicative of a pixel and varying the bias between said lines to cause said particles to migrate to said anode for each selected intersection, the improvement in connection therewith comprising:
- means coupled to said grid line to provide a grid pulse on said line of a given duration and of a given polarity and amplitude indicative of a write bias for said grid line;
means coupled to a selected intersecting cathode line associated with said grid line and selected according to a pixel to be written and to provide a cathode pulse to said cathode line of an opposite polarity to said grid pulse and commencing at the start of said grid pulse but having a longer duration than said given duration whereby said cathode pulse is present when said grid pulse terminates.
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Accused Products
Abstract
There is described a method and apparatus for driving an electrophoretic display during a writing mode. During this mode the cathodes that are not being written into are pulsed in regard to the pulsing of a grid that is being written into. The grid that is being written into is associated with a cathode line which line is caused to assume a writing mode for a longer duration than the pulse applied to the writing grid. At the same time cathode lines which are not being written into are pulsed for a time duration equivalent to the time duration of the writing grid pulse. By pulsing the electrodes in the manner described above, one increases the writing speed of the electrophoretic display while maintaining a bright uniform background for the display.
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Citations
20 Claims
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1. Apparatus for driving an electrophoretic display in a write mode, which display is of the type having a plurality of grid lines insulated from a plurality of cathode lines with said grid and cathode lines positioned perpendicular to one another to provide an X-Y matrix, and said display having an anode electrode, said display enabling a picture to be displayed on said cathode by selectively accessing intersecting grid and cathode lines each indicative of a pixel and varying the bias between said lines to cause said particles to migrate to said anode for each selected intersection, the improvement in connection therewith comprising:
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means coupled to said grid line to provide a grid pulse on said line of a given duration and of a given polarity and amplitude indicative of a write bias for said grid line; means coupled to a selected intersecting cathode line associated with said grid line and selected according to a pixel to be written and to provide a cathode pulse to said cathode line of an opposite polarity to said grid pulse and commencing at the start of said grid pulse but having a longer duration than said given duration whereby said cathode pulse is present when said grid pulse terminates. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of applying writing potentials to an electrophoretic display of the type having a plurality of cathode lines intersecting with and insulated from a plurality of transverse grid lines to form an X-Y matrix with an anode electrode positioned with respect to said matrix to receive electrophoretic particles which are caused to migrate to said anode according to biases placed on said matrix by selecting intersections of a grid and cathode line indicative of a pixel during a writing operation, comprising the step of:
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placing a pulse of a given duration and a first polarity on a selected grid line indicative of one address of said pixel; placing a pulse of a greater duration and an opposite polarity on a selected cathode line indicative of the second address of said pixel, whereby said pulse on said selected cathode line is present when said pulse on said selected grid line terminates to cause said grid line to assume a given polarity when writing of that pixel as selected is complete. - View Dependent Claims (11, 12, 13, 14)
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15. A method for applying writing potentials to the electrodes of an electrophoretic display of the type having a plurality of cathode lines intersecting with and insulated from a plurality of transverse grid lines to form an X-Y matrix, with an anode electrode positioned with respect to said matrix to receive electrophoretic particles according to biases placed on said matrix, where each X-Y intersection of said matrix is indicative of a pixel which is selected by a grid line address and a cathode line address, comprising the steps of:
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placing a pulse of a given duration on a selected grid line indicative of one address of said pixel, placing a pulse of a greater duration on a selected cathode line indicative of a second address of said pixel; and placing pulses of said given duration on all other cathode lines intersecting said grid line and not indicative of said selected pixel, with each of said pulses starting at the same time. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification