Method of compensating for pixel data and liquid crystal display

• US 9,378,684 B2
• Filed: 10/14/2014
• Issued: 06/28/2016
• Est. Priority Date: 11/23/2009
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Dongwoo, Hong, Heejung, Kwon, Kyungjoon, Ahn, Heewon, Cho, Daeho
• Primary Examiner(s): SHERMAN, STEPHEN G
• Application Number:
  US14/514,133
• Publication Number:
  US 20150029084A1
• Time in Patent Office: 623 Days
• Field of Search: 345 87-104, 345204-213, 345690-699
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A method of compensating for pixel data includes extending a side portion and a corner portion of a real screen to set an virtual screen, setting dimming values of the virtual screen using dimming values of the real screen, calculating an amount of light of each of pixels on the real screen using the dimming values of the virtual screen mapped to a predetermined analysis area, and multiplying the amount of light of each pixel by a gain of each pixel to modulate pixel data.

Claims

1. A method of compensating for pixel data comprising:

calculating an amount of light of each of pixels using dimming values of a predetermined analysis area;

setting a first gain value of a side portion and a corner portion of a liquid crystal display panel to be greater than a second gain value of a middle portion of the liquid crystal display panel, wherein the side and corner portions define a perimeter of the display panel; and

multiplying the amount of light of each of first pixels existing in the side portion and the corner portion of the liquid crystal display panel by the first gain value to modulate data of the first pixels and multiplying an amount of light of each of second pixels existing in the middle portion of the liquid crystal display panel by the second gain value to modulate data of the second pixels.

2. The method of claim 1, further comprising:

analyzing an input image;

calculating a representative value of the predetermined analysis area; and

obtaining the dimming values of the predetermined analysis area using the representative value.

3. The method of claim 2, wherein the representative value is calculated by an average value of maximum values among R, G, and B values of pixels in the predetermined analysis area.

4. The method of claim 2, wherein the representative value is calculated by an average value of luminance values of pixels in the predetermined analysis area.

5. The method of claim 2, wherein the obtaining step maps the representative value to a previously set dimming curve.

6. A liquid crystal display comprising:

a liquid crystal display panel;

a backlight unit configured to provide light to the liquid crystal display panel;

a light source driver configured to drive light sources of the backlight unit;

a local dimming controller configured to divide the liquid crystal display panel into a plurality of blocks, calculate a dimming value of each block, control the light source driver using the dimming value of each block, and modulate pixel data of the liquid crystal display panel,

wherein the local dimming controller calculates an amount of light of each of pixels using dimming values of a predetermined analysis area, sets a first gain value of a side portion and a corner portion of a liquid crystal display panel to be greater than a second gain value of a middle portion of the liquid crystal display panel, multiplies the amount of light of each of first pixels existing in the side portion and the corner portion of the liquid crystal display panel by the first gain value to modulate data of the first pixels, and multiplies the amount of light of each of second pixels existing in the middle portion of the liquid crystal display panel by the second gain value to modulate data of the second pixels,

wherein the side and corner portions define a perimeter of the display panel.

7. The liquid crystal display of claim 6, wherein the local dimming controller comprises:

a representative value calculating unit configured to analyze an input image and calculate a representative value of the predetermined analysis area; and

a dimming value selecting unit configured to select the dimming values of the predetermined analysis area using the representative value.

8. The liquid crystal display of claim 7, wherein the representative value calculating unit calculates the representative value by an average value of maximum values among R, G, and B values of pixels in the predetermined analysis area.

9. The liquid crystal display of claim 7, wherein the representative value calculating unit calculates the representative value by an average value of luminance values of pixels in the predetermined analysis area.

10. The liquid crystal display of claim 7, wherein the dimming value selecting unit maps the representative value to a previously set dimming curve and selects the diming values.

11. The liquid crystal display of claim 7, wherein the local dimming controller further comprises a light source controller configured to code the dimming values received from the dimming value selecting unit to data of a SPI format, and supply the coded data to a light source drive.