Methods for driving electro-optic displays

• US 9,412,314 B2
• Filed: 03/26/2009
• Issued: 08/09/2016
• Est. Priority Date: 11/20/2001
• Status: Active Grant

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Inventors: Amundson, Karl R., Zehner, Robert W., Knaian, Ara N., Zion, Benjamin
• Primary Examiner(s): SHERMAN, STEPHEN G
• Application Number:
  US12/411,643
• Publication Number:
  US 20090179923A1
• Time in Patent Office: 2,693 Days
• Field of Search: 345/107, 345/96, 345/204, 345/690
• US Class Current: 1/1
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1681 having two or more microcells partitioned by walls, e.g. of microcup type
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• 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

Abstract

An electro-optic display, having at least one pixel capable of achieving any one of at least four different gray levels including two extreme optical states, is driven by displaying a first image on the display, and rewriting the display to display a second image thereon, wherein, during the rewriting of the display, any pixel which has undergone a number of transitions exceeding a predetermined value without touching an extreme optical state, is driven to at least one extreme optical state before driving that pixel to its final optical state in the second image.

Claims

1. A method for driving an electro-optic display having at least one pixel capable of achieving any one of at least four different gray levels including two extreme optical states, the method comprising:

displaying a first image on the display; and

rewriting the display to display a second image thereon,

the method permitting any pixel to undergo at least two transitions without touching an extreme optical state, but being such that during the rewriting of the display any pixel which has undergone a number of transitions exceeding a predetermined value, the predetermined value being at least two, without touching an extreme optical state, is driven to at least one extreme optical state before driving that pixel to its final optical state in the second image, wherein the rewriting of the display is effected such that, once a pixel has been driven from one extreme optical state to a gray level, which is not one of the two extreme optical states, in the direction of the other extreme optical state by a pulse of one polarity, the pixel does not receive a pulse of the opposed polarity until it has reached the opposed extreme optical state.

2. A method for driving an electro-optic display having at least one pixel capable of achieving any one of at least four different gray levels including two extreme optical states, the method comprising:

displaying a first image on the display; and

rewriting the display to display a second image thereon,

the method permitting any pixel to undergo at least two transitions without touching an extreme optical state, but being such that during the rewriting of the display any pixel which has undergone a number of transitions exceeding a predetermined value, the predetermined value being at least two, without touching an extreme optical state, is driven to at least one extreme optical state before driving that pixel to its final optical state in the second image, wherein said predetermined value is not greater than N/2, where N is the total number of gray levels capable of being displayed by a pixel.

3. A method according to claim 2 wherein the rewriting of the display is effected by applying to the or each pixel any one or more of voltages −

V, 0 and +V.

4. A method according to claim 2 wherein the rewriting of the display is effected such that, for any series of transitions undergone by a pixel, the integral of the applied voltage with time is bounded.

5. A method according to claim 2 wherein the rewriting of the display is effected such that the impulse applied to a pixel during a transition depends only upon the initial and final gray levels of that transition.