Driving methods and waveforms for electrophoretic displays

Abstract

This application is directed to driving methods for electrophoretic displays. The driving methods and waveforms have the advantage that they provide a clean and smooth transition from one image to another image, without flashing or other undesired visual interruptions. The methods also provide faster image transitions. In an embodiment, a method drives a display device from a first image to a second image wherein images of a first color are displayed with a background of a second color, which method comprises driving pixels of the first color directly to the second color before driving pixels of the second color directly to the first color.

1 . A method for driving an electrophoretic display comprising pixels from a first image to a second image, wherein:
 both the first and second images comprise dark pixel and light pixels;   a first group of pixels are dark in the first image and light in the second image;   a second group of pixels are dark in both the first and second images;   a third group of pixels are light in the first image and dark in the second image and   a fourth group of pixels are light in both the first and second images;   the method comprising:   (a) driving the first group of pixels from the dark state to the light state while maintaining the second group of pixels in the dark state; and   (b) after completing step (a), driving the third group of pixels from the light state to the dark state while maintaining the fourth group of pixels in the light state.   
     
     
         2 . The method of  claim 1 , wherein the dark pixels are black and the light pixels are white. 
     
     
         3 . The method of  claim 1 , wherein the electrophoretic display comprises a thin film transistor back plane. 
     
     
         4 . The method of  claim 1 , wherein the electrophoretic display comprises an electrophoretic medium comprising oppositely charged dark and light particles. 
     
     
         5 . The method of  claim 1 , wherein the first image comprises a first text character and the second image comprises a second text character. 
     
     
         6 . A display controller comprising circuit logic for executing the method of  claim 5 . 
     
     
         7 . A method for transitioning an electrophoretic display comprising pixels between a first image and a second image, wherein
 both the first and second images comprise dark pixel and light pixels;   a first group of pixels are dark in the first image and light in the second image;   a second group of pixels are dark in both the first and second images;   a third group of pixels are light in the first image and dark in the second image and   a fourth group of pixels are light in both the first and second images;
 the method comprising: 
 (a) driving the third group of pixels from the light state to the dark state while maintaining the fourth group of pixels in the light state; and 
 (b) after completing step (a), driving the first group of pixels from the dark state to the light state while maintaining the second group of pixels in the dark state. 
   
     
     
         8 . The method of  claim 7 , wherein the dark pixels are black and the light pixels are white. 
     
     
         9 . The method of  claim 7 , wherein the electrophoretic display comprises a thin film transistor back plane. 
     
     
         10 . The method of  claim 7 , wherein the electrophoretic display comprises an electrophoretic medium comprising oppositely charged dark and light particles. 
     
     
         11 . The method of  claim 7 , wherein the first image comprises a first text character and the second image comprises a second text character. 
     
     
         12 . A display controller comprising circuit logic for executing the method of  claim 11 .