Methods for driving electro-optic displays

• US 9,495,918 B2
• Filed: 02/28/2014
• Issued: 11/15/2016
• Est. Priority Date: 03/01/2013
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Harrington, Demetrious Mark, Crounse, Kenneth R., Amundson, Karl Raymond, Aprea, Matthew J., Sjodin, Theodore A.
• Primary Examiner(s): Watko, Julie Anne
• Application Number:
  US14/193,081
• Publication Number:
  US 20140292830A1
• Time in Patent Office: 991 Days
• Field of Search: 345/690
• US Class Current: 1/1
• CPC Class Codes: G02B 26/005 based on electrowetting
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor
• CPC Class Codes: G02F 1/1681 having two or more microcells partitioned by walls, e.g. of microcup type
• CPC Class Codes: G09G 2230/00 Details of flat display driving waveforms
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2310/062 Waveforms for resetting a plurality of scan lines at a time
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• CPC Class Codes: G09G 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 2380/14 Electronic books and readers
• CPC Class Codes: G09G 3/2007 Display of intermediate tones
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/2048 with addition of random noise to an image signal or to a gradation threshold
• CPC Class Codes: G09G 3/2051 with use of a spatial dither pattern
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167
• CPC Class Codes: G09G 3/38 : using electrochromic devices

Abstract

A method is provided for driving electro-optic displays, especially bistable displays, to avoid edge effects when driving a limited area of the display. Pixels in an edge elimination region, at least one pixel wide and substantially surrounding the limited area, are driven from their original gray level to an intermediate gray level, and then back to their original gray level.

Claims

1. A method of driving an electro-optic display having a plurality of pixels, the method comprising applying a local drive scheme to change the optical state of at least one limited area of the display and driving pixels in an edge elimination region, at least one pixel wide and substantially surrounding the at least one limited area, from their original gray level to an intermediate gray level, and then back to their original gray level.

2. A method according to claim 1 wherein the edge elimination region comprises pixels which share only a common corner with the at least one limited area.

3. A method according to claim 1 wherein the edge elimination region comprises pixels within the at least one limited area.

4. A method according to claim 1 wherein the edge elimination region is more than one pixel wide, and the pixels in the edge elimination region are driven to differing intermediate gray levels depending upon the distance of the pixels from the boundary of the at least one limited area.

5. A display controller adapted to carry out the method of claim 1, the display controller being capable of driving an electro-optic display having a plurality of pixels and comprising edge detection means for detecting the edges of limited areas of the display undergoing a transition, and for determining an edge elimination region at least one pixel wide and substantially surrounding the at least one limited area, the display controller being arranged to drive the pixels in the edge elimination region from their original gray level to an intermediate gray level, and then back to their original gray level.