Drivers providing DC-balanced refresh sequences for color electrophoretic displays
AssigneeE Ink Corporation
InventorsStephen J. Telfer, Christopher L. Hoogeboom, Kenneth R. Crounse
Life of this patent
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Abstract
A method for driving an electro-optic display having a front electrode, a backplane, and a display medium including at least three differently-colored particles, wherein the medium is positioned between the front electrode and the backplane. The method includes applying a reset phase and a color transition phase to the display such that the sum of all impulses results in an offset that maintains a DC-balance across the display medium. The invention additionally includes controllers for executing the method.
Claims11
A method for driving an electrophoretic display having a front electrode, a backplane, and a display medium positioned between the front electrode and the backplane, the display medium comprising three sets of differently-colored particles, the method comprising:
- applying a reset phase and a color transition phase to the display, the reset phase comprising:
- applying a first signal having a first polarity, a first amplitude as a function of time, and a first duration on the front electrode;
- applying a second signal having a second polarity opposite the first polarity, a second amplitude as a function of time, during the first duration on the backplane;
- applying a third signal having the second polarity opposite the first polarity, a third amplitude as a function of time, during a second duration on the front electrode;
- applying a fourth signal having the first polarity and the first amplitude as a function of time plus an impulse offset proportional to a kickback voltage experienced by the display medium, during the second duration on the backplane;
- the color transition phase comprising:
- applying a fifth signal having the second polarity, a fourth amplitude as a function of time, and a third duration preceded by the first and second durations on the front electrode;
- applying a sixth signal having the first polarity, a fifth amplitude as a function of time, and a fourth duration preceded by the first and second durations on the backplane;
- wherein the sum of the first and second amplitudes as a function of time integrated over the first duration, and the sum of the first, second, and third amplitudes as a function of time integrated over the second duration, and the fourth amplitude as a function of time integrated over the third duration, and the fifth amplitude as a function of time integrated over the fourth duration produces the impulse offset proportional to a kickback voltage experienced by the display medium and designed to maintain a DC-balance on the display medium over the reset phase and the color transition phase.
A controller for an electrophoretic display comprising a front electrode, a backplane, and a display medium positioned between the front electrode and the backplane, the display medium comprising three sets of differently-colored particles, the controller being operatively coupled to the front electrode and the backplane, and configured to apply a reset phase and a color transition phase to the display,
- the reset phase comprising:
- applying a first signal having a first polarity, a first amplitude as a function of time, and a first duration on the front electrode;
- applying a second signal having a second polarity opposite the first polarity, a second amplitude as a function of time, during the first duration on the backplane;
- applying a third signal having the second polarity opposite the first polarity, a third amplitude as a function of time, during a second duration on the front electrode;
- applying a fourth signal having the first polarity and the first amplitude as a function of time plus an impulse offset proportional to a kickback voltage experienced by the display medium, during the second duration on the backplane;
- the color transition phase comprising:
- applying a fifth signal having the second polarity, a fourth amplitude as a function of time, and a third duration preceded by the first and second durations on the front electrode;
- applying a sixth signal having the first polarity, a fifth amplitude as a function of time, and a fourth duration preceded by the first and second durations on the backplane;
- wherein the sum of the first and second amplitudes as a function of time integrated over the first duration, and the sum of the first, second, and third amplitudes as a function of time integrated over the second duration, and the fourth amplitude as a function of time integrated over the third duration, and the fifth amplitude as a function of time integrated over the fourth duration produces an impulse offset proportional to a kickback voltage experienced by the display medium and designed to maintain a DC-balance on the display medium over the reset phase and the color transition phase.
Dependencies are inferred from the claim text.