Methods for driving bistable electro-optic displays, and apparatus for use therein

• US 8,558,785 B2
• Filed: 05/18/2010
• Issued: 10/15/2013
• Est. Priority Date: 04/30/1999
• Status: Expired due to Fees

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink Holdings Incorporated
• Inventors: Zehner, Robert W., Gates, Holly G., Amundson, Karl R., Au, Joanna F., Knaian, Ara N., Arango, Alexi C., Zalesky, Jonathan L.
• Primary Examiner(s): Awad, Amr
• Assistant Examiner(s): WILLIS, RANDAL L
• Application Number:
  US12/782,344
• Publication Number:
  US 20100220122A1
• Time in Patent Office: 1,246 Days
• Field of Search: 345/105, 345/107, 345/95
• US Class Current: 345/107
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2310/02 Addressing, scanning or driving the display screen or processing steps related thereto
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2310/063 Waveforms for resetting the whole screen at once
• CPC Class Codes: G09G 2310/068 Application of pulses of alternating polarity prior to the drive pulse in electrophoretic displays
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• 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 3/2011 : by amplitude modulation
• CPC Class Codes: G09G 3/2018 : by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2081 : with combination of amplitude modulation and time modulation space and time error diffusion G09G3/2066
• 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 5/10 : Intensity circuits
• CPC Class Codes: G09G 5/18 : Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12

Abstract

A bistable electro-optic display has a plurality of pixels, each of which is capable of displaying at least three gray levels. The display is driven by a method comprising: storing a look-up table containing data representing the impulses necessary to convert an initial gray level to a final gray level; storing data representing at least an initial state of each pixel of the display; receiving an input signal representing a desired final state of at least one pixel of the display; and generating an output signal representing the impulse necessary to convert the initial state of said one pixel to the desired final state thereof, as determined from said look-up table. The invention also provides a method for reducing the remnant voltage of an electro-optic display.

Claims

1. A method of driving a bistable electro-optic display having a plurality of pixels, the method comprising:

storing data representing at least an initial state of each pixel of the display;

storing first and second look-up tables;

receiving an input signal representing a desired final state of at least one pixel of the display; and

generating an output signal representing the impulse necessary to convert the initial state of said one pixel to the desired final state thereof, as determined from said look-up tables,

wherein said second look-up table stores a plurality of standard waveforms, each of said plurality of standard waveforms having at least one parameter, and said first look-up table stores, for each combination of initial state and final state of a pixel, a pointer denoting which of the standard waveforms in the second look-up table is to be used for the transition from the initial state to the final state, and the value or values of the at least one parameter to be used in this standard waveform.

2. A method according to claim 1 further comprising storing data representing at least one prior state of each pixel prior to said initial state thereof, and wherein said output signal is generated dependent upon the data representing the at least one prior state of the relevant pixel.

3. A method according to claim 1 further comprising receiving a temperature signal representing the temperature of at least one pixel of the display, and wherein said output signal is generated dependent upon said temperature signal.

4. A method according to claim 1 further comprising receiving a humidity signal representing ambient humidity, and wherein said output signal is generated dependent upon said humidity signal.

5. A method according to claim 1 further comprising receiving a lifetime signal representing the operating lifetime of at least one pixel, and wherein said output signal for said at least one pixel is generated dependent upon said lifetime signal.

6. A method according to claim 1 wherein there is applied to each pixel in succession a pre-pulse which drives said pixel to one of its extreme optical states, and an addressing pulse which drives said pixel from said one extreme optical state to the desired final state.

7. A method according to claim 1 wherein there is applied to each pixel in succession a first pre-pulse which drives said pixel to one of its extreme optical states, a second pre-pulse which drives said pixel from said one extreme optical state to the opposed extreme optical state, and an addressing pulse which drives said pixel from said opposed extreme optical state to the desired final state.

8. A method according to claim 1 wherein the display is an electrophoretic display.

9. A method according to claim 8 wherein the display is an encapsulated electrophoretic display.

10. A method according to claim 8 wherein the display is a microcell display comprising charged particles and a suspending fluid retained within a plurality of cavities formed in a carrier medium.

11. A method according to claim 1 wherein the display is a passive matrix display.

12. A device controller for controlling a bistable electro-optic display having a plurality of pixels, said controller comprising:

storage means arranged to store data representing at least an initial state of each pixel of the display, said storage means also being arranged to store first and second look-up tables, said second look-up table storing a plurality of standard waveforms, each of said plurality of standard waveforms having at least one parameter, and said first look-up table storing, for each combination of initial state and final state of a pixel, a pointer denoting which of the standard waveforms in the second look-up table is to be used for the transition from the initial state to the final state, and the value or values of the at least one parameter to be used in this standard waveform;

input means for receiving an input signal representing a desired final state of at least one pixel of the display;

calculation means for determining, from the input signal, the stored data representing the initial and desired final states of said pixel, and the first and second look-up tables, the impulse required to change the initial state of said one pixel to the desired final state; and

output means for generating an output signal representative of said impulse.

13. A device controller according to claim 12 wherein said storage means is arranged to store data representing at least one prior state of each pixel prior to said initial state thereof, and said output means is arranged to generate said output signal dependent upon the data representing the at least one prior state of the relevant pixel.

14. A device controller according to claim 12 wherein said input means is arranged to receive a temperature signal representing the temperature of at least one pixel of the display, and said output means is arranged to generate said output signal dependent upon said temperature signal.

15. A device controller according to claim 12 wherein said input means is arranged to receive a humidity signal representing ambient humidity, and said output means is arranged to generate said output signal dependent upon said humidity signal.

16. A device controller according to claim 12 wherein said input means is arranged to receive a lifetime signal representing the operating lifetime of at least one pixel of the display, and said output means is arranged to generate said output signal for said at least one pixel dependent upon said lifetime signal.

17. A device controller according to claim 12 wherein said output means is arranged to generate in succession a pre-pulse which drives said pixel to one of its extreme optical states, and an addressing pulse which drives said pixel from said one extreme optical state to the desired final state.

18. A device controller according to claim 12 wherein said output means is arranged to generate in succession a pre-pulse which drives one pixel of its associated display to one of its extreme optical states, a second pre-pulse which drives said one pixel from said one extreme optical state to the opposed extreme optical state, and an addressing pulse which drives said one pixel from said one extreme optical state to the desired final state.

19. A bistable electro-optic display having a plurality of pixels, each of which is capable of displaying at least three gray levels, and a controller according to claim 12 arranged to control the electro-optic display.