Multi-particle electrophoretic display having low-flash image updates

Abstract

Electrophoretic displays with multi-particle electrophoretic media, and particularly improved methods for driving such multi-particle electrophoretic media using an active matrix backplane and controller. These driving methods use faster gate updates and differential intervals between a series of gate updates for a given pixel. These methods can be extended to any electrophoretic display using push-pull waveforms and are particularly well-suited for novel multi-particle electrophoretic displays capable of generating more than four colors per pixel. Compared to addressing using conventional constant-frame-spacing updates, electrophoretic displays using such methods appear to be less "flickering".

Claims

1. An electrophoresis display, comprising: One transparent electrode; An active matrix backplane includes a plurality of pixel electrodes, each pixel electrode coupled to a thin-film transistor including a gate line and a source line, and each pixel electrode coupled to a storage capacitor; an electrophoretic medium disposed between the light-transmitting electrode and the active matrix backplane, wherein the electrophoretic medium contains at least three different types of charged pigment particles; a controller coupled to a plurality of gate lines and a plurality of source lines of the plurality of pixel electrodes, the controller being configured to address the pixel electrodes in a column-by-column manner, the controller being further configured to update an image on the electrophoretic display by performing the following steps: addressing a first column of pixel electrodes by providing a first gate voltage at a first time; addressing a second column of pixel electrodes by providing a second gate voltage at a second time; and addressing the first column of pixel electrodes by providing a third gate voltage at a third time. The second column of pixel electrodes is addressed by providing a fourth gate voltage at a fourth time; and the first column of pixel electrodes is addressed by providing a fifth gate voltage at a fifth time, wherein the first time, the second time, the third time, the fourth time, and the fifth time are different, and the elapsed time between the first time and the third time is shorter than the elapsed time between the third time and the fifth time, wherein when the controller updates the image, a portion of the electrophoretic medium above one of the pixel electrodes in the first column of pixel electrodes and a portion of the electrophoretic medium above one of the pixel electrodes in the second column of pixel electrodes undergo the same color transition.

2. The electrophoretic display as claimed in claim 1, wherein the time elapsed between the third time and the fifth time is at least twice the time elapsed between the first time and the third time.

3. The electrophoretic display as requested in claim 1, wherein the time elapsed between the first time and the third time is less than 20 milliseconds, optionally less than 10 milliseconds, optionally about 6 milliseconds or less.

4. The electrophoretic display of claim 1, wherein the controller simultaneously provides a first source voltage to a pixel of the first column of pixel electrodes at a first time and provides a second source voltage to the pixel of the first column of pixel electrodes at a third time, and the polarity of the first source voltage is opposite to the polarity of the second source voltage.

5. The electrophoretic display as claimed in claim 4, wherein the amplitude of the first source voltage is different from the amplitude of the second source voltage.

6. The electrophoretic display as claimed in claim 4, wherein the amplitude of the first source voltage and the amplitude of the second source voltage are between -15V and +15V or between -24V and +24V.

7. The electrophoretic display as claimed in claim 4, wherein the controller simultaneously provides a third source voltage to the pixel of the first column of pixel electrodes at the fifth time.

8. The electrophoretic display as claimed in claim 7, wherein the first source voltage and the third source voltage have the same polarity and amplitude.

9. The electrophoretic display of claim 1, wherein the controller performs the following additional steps: addressing a third column of pixel electrodes by providing a sixth gate voltage at a sixth time; and addressing the third column of pixel electrodes by providing a seventh gate voltage at a seventh time, wherein the first time, the second time, the third time, the fourth time, the fifth time, the sixth time, and the seventh time are different, and the elapsed time between the first time and the third time is the same as the elapsed time between the sixth time and the seventh time.

10. The electrophoretic display of claim 1, wherein the electrophoretic medium comprises a reflective white particle and at least one subtractive color particle or a reflective white particle and at least one reflective color particle.

11. The electrophoretic display of claim 1, wherein the electrophoretic medium comprises a fourth type of electrophoretic particles.

12. An electrophoretic display as claimed in claim 11, wherein two types of particles of such types are negatively charged and two types of particles of such types are positively charged, or wherein one type of particles of such types is negatively charged and three types of particles of such types are positively charged, or wherein three types of particles of such types are negatively charged and one type of particles of such types is positively charged.

13. An electrophoretic display as claimed in any of claims 1 to 12, wherein the electrophoretic medium is encapsulated in microcapsules or microcells.

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