Multi-line addressing methods and apparatus

• US 8,237,635 B2
• Filed: 10/10/2011
• Issued: 08/07/2012
• Est. Priority Date: 09/30/2004
• Status: Expired due to Fees

• Current Assignee: Cambridge Display Technology Limited (Sumitomo Chemical Company Limited)
• Original Assignee: Cambridge Display Technology Limited (Sumitomo Chemical Company Limited)
• Inventors: Smith, Euan Christopher, Routley, Paul Richard, Halls, Jonathan James Michael
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): STONE, ROBERT M
• Application Number:
  US13/269,986
• Publication Number:
  US 20120081416A1
• Time in Patent Office: 302 Days
• Field of Search: 345/76, 345/82, 345/83
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2310/0208 using active addressing
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

This invention relates to methods and apparatus for driving emissive, in particular organic light emitting diodes (OLED), displays using multi-line addressing (MLA) techniques. Embodiments of the invention are particularly suitable for use with so-called passive matrix OLED displays. A method of driving an emissive display, the display comprising a plurality of pixels each addressable by a row electrode and a column electrode, the method comprising: driving a plurality of column electrodes with a first set of column drive signals; and driving two or more row electrodes with a first set of forward bias row drive signals at the same time as the column electrode driving with the column drive signals; then driving the plurality of column electrodes with a second and subsequent sets of column drive signals; and driving the two or more row electrodes with a second and subsequent sets of forward bias row drive signals at the same time as the column electrode driving with the second column drive signals.

Claims

1. An emissive display comprising:

a plurality of pixels each addressable by a row electrode and a column electrode; and

a display driver, said display driver comprising;

means for driving a plurality of said column electrodes with a first set of column drive signals;

means for driving a first group of two or more of said row electrodes with a first set of forward bias row drive signals at the same time as said column electrode driving with said first column drive signals, wherein said first set of forward bias row drive signals is to cause a plurality of pixels in each of two or more rows of the display to emit light at the same time;

means for driving said plurality of column electrodes with a second set of column drive signals;

means for driving a second group of two or more row electrodes with a second set of forward bias row drive signals at the same time as said column electrode driving with said second column drive signals, wherein said second set of forward bias row drive signals is to cause pixels in two or more rows of the display to emit light at the same time; and

means for selecting row electrodes of said first group of two or more row electrodes based on correlation or expected correlation between rows of image data and for selecting row electrodes of said second group of row electrodes based on correlation or expected correlation between rows of image data,

wherein the means for selecting is for selection of said first and second column drive signals and said row electrodes of said first and second groups such that a desired luminescence of said OLED pixels driven by said row and column electrodes is obtained by a substantially linear sum of luminances determined by said first row and column drive signals and luminances determined by said second row and column drive signals and to thereby build up a luminescence profile of a said row over a plurality of row scan periods.

2. The emissive display of claim 1, wherein the display driver comprises an emissive display driver circuit for driving said emissive display, said emissive display driver circuit comprising:

one or more column drivers to simultaneously drive a plurality of said column electrodes; and

one or more row drivers to simultaneously drive a plurality of said row electrodes corresponding to said column electrodes at the same time as said column electrode driving, such that a drive for a said column electrode is shared between a plurality of said row drivers.

3. The emissive display of claim 1, wherein said row and column drivers comprise circuits to provide a controllable substantially constant current.

4. The emissive display of claim 1, wherein said emissive display is an OLED display.

5. The emissive display of claim 1, wherein said display driver comprises an integrated circuit die chip comprising a plurality of drivers configured to drive a plurality of electrodes of said emissive display simultaneously, and display drive processing circuitry configured to determine drive signals for said plurality of electrodes;

and wherein said die has an aspect ratio of greater than 10 to 1 length to breadth.

6. The emissive display of claim 1, wherein said row and column drivers comprise circuits to provide a controllable substantially constant current.

7. The emissive display of claim 1, wherein said two or more row electrodes drive adjacent rows of said pixels.

8. The emissive display of claim 1, wherein said two or more row electrodes drive separated or alternate rows of said pixels.

9. The emissive display of claim 1, wherein each said pixel comprises at least two subpixels of at least two different colours, each subpixel being addressable by a said row and column electrode.

10. The emissive display of claim 9, wherein said means for driving a first group of two or more row electrodes and/or said means for driving a second group of two or more row electrodes comprises means for driving row electrodes of said two or more subpixels of a common pixel.

11. The emissive display of claim 9, wherein said means for driving a first group of two or more row electrodes and/or said means for driving a second group of two or more row electrodes comprises means for driving row electrodes of subpixels of the same colour.