SUBPIXEL LAYOUTS FOR HIGH BRIGHTNESS DISPLAYS AND SYSTEMS

• US 20080049048A1
• Filed: 04/12/2007
• Published: 02/28/2008
• Est. Priority Date: 08/28/2006
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Clairvoyante, Inc. (Samsung Electronics Co. Ltd.)
• Inventors: Credelle, Thomas Lloyd, Brown Elliott, Candice Hellen, Botzas, Anthony
• Granted Patent: US 8,018,476 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• 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 3/2074 using sub-pixels

Abstract

A display device comprises a display panel comprising high brightness subpixel repeating groups—for example, RGBW display panels. Displays comprise subpixel repeating groups that include first and second primary color stripes and third and fourth primary color subpixels that are disposed on a checkerboard pattern. A subpixel rendering operation includes, or is followed by, a white subpixel adjustment operation that adjusts the brightness of the white subpixels in the areas of the displayed image that contain high spatial frequency features such as lines and text, in order to improve image quality such as image contrast.

Claims

1. A display device comprising:

a display panel substantially comprising a plurality of a subpixel repeating group;

said subpixel repeating group comprising subpixels of first, second, third and fourth primary colors arranged in first and second rows, wherein one of said first, second, third and fourth primary colors is white and remaining primary colors are saturated;

said subpixel repeating group further comprising a column of said first, primary color subpixels and a column of said second primary color subpixels each forming a stripe;

said subpixel repeating group further comprising a column of third and fourth primary color subpixels disposed in an alternating pattern in the column;

an input image data unit configured to receive source image data; and

a subpixel rendering unit configured to subpixel render said input image data for rendering on said display panel;

said subpixel rendering unit performing a white subpixel adjustment operation for adjusting a brightness level of said white subpixels using white data values of said source image data.

2. The display device of claim 1 wherein said source image data is specified in said three saturated primary colors of the subpixels;

and wherein said display device further comprises a gamut mapping unit for mapping said source image data from a color gamut specified in said three saturated primary colors to a color gamut in said first, second, third and fourth primary colors.

3. The display device of claim 1 wherein said white subpixel adjustment operation adjusts the brightness level of a white subpixel using a difference between white data values in adjacent source image data pixels.

4. The display device of claim 1 wherein said white subpixel adjustment operation adjusts the brightness level of a white subpixel using a maximum absolute value of a difference between white data values in adjacent source image data pixels.

5. The display device of claim 1 wherein said white subpixel adjustment operation adjusts the brightness level of a white subpixel using an absolute value of a difference between white data values in adjacent source image data pixels.

6. The display device of claim 1 wherein said white subpixel adjustment operation adjusts the brightness level of a white subpixel using a scaling factor.

7. The display device of claim 1 wherein said subpixel rendering unit performs area resampling of said source image data to produce luminance values for each of the subpixels of the display panel.

8. The display device of claim 1 wherein said source image data is specified in said three saturated primary colors of the subpixels;

wherein said display device further comprises a gamut mapping unit for mapping said source image data from a color gamut specified in said three saturated primary colors to a color gamut in said first, second, third and fourth primary colors such that each source image data pixel comprises a white data value; and

wherein said white subpixel adjustment operation adjusts the brightness level of a white subpixel by

calculating an average of white data values for two adjacent source image pixels to produce white subpixel value, W;

calculating a difference in luminance, Δ

L, between said white data values for two adjacent source image pixels;

multiplying an absolute value of Δ

L by a scaling factor, S1, to produce white adjustment quantity, W-adjust, and

subtracting W-adjust from W.