Liquid crystal display and driving method thereof

• US 20090310077A1
• Filed: 12/15/2008
• Published: 12/17/2009
• Est. Priority Date: 06/12/2008
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Jinsung, Jang, Suhyuk
• Granted Patent: US 8,319,717 B2
• Time in Patent Office: Days
• US Class Current: 349/151
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• 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 2320/0219 Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0613 The adjustment depending on the type of the information to be displayed
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/023 using energy recovery or conservation
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

The exemplary embodiment relates to a liquid crystal display device and a driving method thereof for reducing heat and electric consumption power of the data driving circuit. The exemplary embodiment includes: a liquid crystal display panel including a plurality of data lines crossing a plurality of gate lines and liquid crystal cells arranged in a matrix e; a timing controller generating a polarity control signal, deciding if a predetermined weak pattern data is input, and shifting a phase of the polarity control signal in a next frame period following a frame showing the weak pattern data when the weak pattern data is input; a data driving circuit reversing the polarity of the data voltage in response to the polarity control signal and supplying to the data lines; and a gate driving circuit supplying a gate pulse to the gate lines sequentially.

Claims

1. A liquid crystal display device comprising:

a liquid crystal display panel including a plurality of data lines crossing a plurality of gate lines and liquid crystal cells arranged in a matrix;

a timing controller generating a polarity control signal, deciding if a predetermined weak pattern data is input, and shifting a phase of the polarity control signal in a next frame period following a frame showing the weak pattern data when the weak pattern data is input;

a data driving circuit reversing the polarity of the data voltage in response to the polarity control signal and supplying to the data lines; and

a gate driving circuit supplying a gate pulse to the gate lines sequentially.

2. The device according to the claim 1, wherein the timing controller comprises:

a data analyzer deciding each gray-scale level of the input digital video data based on most significant bits of the input digital video data, deciding a representative gray-scale level of each line based on each gray-scale level to detect the weak pattern data, and generating a selection signal within a blank period between the previous frame period and the next frame period when the weak pattern data is inputted; and

a phase controller generating a first polarity control signal and a second polarity control signal having different phase from the first polarity control signal, and selecting any one of the first and the second polarity control signals in response to the selection signal.

3. The device according to the claim 2, wherein a logic reversing period of the second polarity control signal is substantially same with a logic reversing period of the first polarity control signal.

4. A liquid crystal display device comprising:

a liquid crystal display panel including a plurality of data lines crossing a plurality of gate lines and liquid crystal cells arranged in a matrix;

a timing controller generating a polarity control signal, deciding if a predetermined weak pattern data and a DC image sticking data are input, and shifting a phase of the polarity control signal in a next frame period following a frame showing the weak pattern data when the weak pattern data and the DC image sticking data are input;

a data driving circuit reversing the polarity of the data voltage in response to the polarity control signal, expanding a horizontal polarity inversion period of the data voltages in response to the dot inversion control signal, and supplying to the data lines; and

a gate driving circuit supplying a gate pulse to the gate lines sequentially.

5. The device according to the claim 4, wherein the timing controller shifts a phase of the polarity control signal with one frame period, and reverses the dot inversion control signal in one frame period frequency when the DC image sticking data is input.

6. A method for driving a liquid crystal display device including a plurality of data lines crossing a plurality of gate lines and liquid crystal cells arranged in a matrix comprising:

generating a polarity control signal;

deciding if a predetermined weak pattern data is input, and shifting the polarity control signal within a next frame period showing the weak pattern data when the weak pattern data is input;

reversing the polarity of data voltages by controlling a data driving circuit with the polarity control signal, and supplying the reversed data voltages to the data lines; and

supplying a gate pulse to the gate line sequentially by controlling a gate driving circuit.

7. The method according to the claim 6, wherein the shifting the phase of the polarity control signal comprises:

deciding each gray-scale level of the input digital video data based on most significant bits of the input digital video data, deciding a representative gray-scale level of each line based on each gray-scale level to detect the weak pattern data, and generating a selection signal within a blank period between the previous frame period and the next frame period when the weak pattern data is inputted;

generating a first polarity control signal and a second polarity control signal having different phase from the first polarity control signal; and

selecting any one of the first and the second polarity control signals in response to the selection signal.

8. The method according to the claim 7, wherein a logic reversing period of the second polarity control signal is substantially same with a logic reversing period of the first polarity control signal.