Liquid crystal display capable of adjusting brightness level in each of plural division areas and method of driving the same

• US 8,669,932 B2
• Filed: 06/26/2006
• Issued: 03/11/2014
• Est. Priority Date: 06/29/2005
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Hong Chul
• Primary Examiner(s): HORNER, JONATHAN R
• Application Number:
  US11/474,554
• Publication Number:
  US 20070002003A1
• Time in Patent Office: 2,815 Days
• Field of Search: 345/87, 345/89, 345/102
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A liquid crystal display and a driving method thereof are provided. The liquid crystal display comprises a liquid crystal panel; a gate driver; a data driver; a timing controller supplying a control signal of the gate driver and a control signal of the data driver and supplying a brightness variable signal depending on an average of gray levels of image data; and a backlight unit adjusting a brightness level of the lamp in response to a plurality of brightness variable signals, wherein the timing controller divides the liquid crystal panel into a first division area, which displays image data, equal to or smaller than an average of reference gray levels and dispersion of reference gray levels and a second division area comprising areas other than the first division area by calculating an average and dispersion of gray levels of the image data with a line unit, and supplies a first brightness variable signal adjusting a brightness level of the first division area and a second brightness variable signal adjusting a brightness level of the second division area.

Claims

1. A liquid crystal display that can adjust a brightness level in each of a plurality of division areas, the liquid crystal display comprising:

a liquid crystal panel in which pixels are formed at intersections of a plurality of gate lines and a plurality of data lines, the liquid crystal panel being divided into a first division area and a second division area based on a comparison between image data and an average of reference gray levels and dispersion of the reference gray levels, the first division area being a blank area which displays black color having image data equal to or less than the average of the reference gray levels and dispersion of the reference gray level, the second division area being an area other than the first division area and that displays image data higher than the average of the reference gray levels and the dispersion of the reference gray level;

a gate driver that supplies a scan signal to the plurality of gate lines;

a data driver that converts an input image data into analog pixel signals and that supplies the converted pixel signals to the plurality of data lines;

a timing controller that supplies a first control signal to the gate driver, a second control signal to the data driver, and that supplies a first brightness variable signal to adjust a brightness level of the first division area and a second brightness variable signal to adjust a brightness level of the second division area; and

a backlight unit that adjusts a brightness level of a first lamp irradiating a light to the first division area of the liquid crystal panel in response to the first brightness variable signal, and a brightness level of a second lamp irradiating a light to the second division area of the liquid crystal panel in response to the second brightness variable signal,

wherein the timing controller generates the first brightness variable signal based on an average of brightness level of the first division area and the second brightness variable signal based on an average of brightness level of the second division area,

the brightness levels of the first and second division areas are independently adjusted each other.

2. The liquid crystal display of claim 1, wherein the timing controller adjusts the brightness level of the second division area to be higher than the brightness level of the first division area.

3. The liquid crystal display of claim 1, wherein the backlight unit adjusts an on-time of the first lamp which irradiates light to the first division area in response to the first brightness variable signal and adjusts an on-time of a second lamp which irradiates light to the second division area in response to the second brightness variable signal.

4. A driving method of a liquid crystal display that can adjust a brightness level in each of a plurality of division areas, the method comprising:

calculating an average value and a dispersion value of gray levels of the input image data corresponding to each of data lines;

setting a reference of the average value and a reference of the dispersion value;

dividing a liquid crystal panel into a first division area and a second division area based on a comparison between the input image data and an average of reference gray levels and dispersion of the reference gray levels, wherein the first division area is a blank area which displays black color having image data equal to or less than the average of the reference gray levels and dispersion of the reference gray level, and the second division area is an area other than the first division area and that displays image data higher than the average of the reference gray levels and the dispersion of the reference gray level; and

adjusting a brightness level of the first division area based on an average of brightness level of the first division area and adjusting a brightness level of the second division area based on an average of brightness level of the second division area.

5. The driving method of claim 4, wherein adjusting a brightness level comprises adjusting a brightness level of the second division area to be higher than that of the first division area.

6. The driving method of claim 4, wherein adjusting a brightness level comprises adjusting an on-time of a first lamp which irradiates light to the first division area in response to the first brightness variable signal and adjusting a second on-time of a lamp which irradiates light to the second division area in response to the second brightness variable signal.