Liquid crystal display device and driving method thereof

• US 7,724,228 B2
• Filed: 06/24/2005
• Issued: 05/25/2010
• Est. Priority Date: 11/29/2004
• Status: Expired due to Fees

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lee, Ju Young, Chum, Jae Bum
• Primary Examiner(s): Nguyen; Chanh
• Assistant Examiner(s): Mistry; Ram A
• Application Number:
  US11/165,045
• Publication Number:
  US 20060114207A1
• Time in Patent Office: 1,796 Days
• Field of Search: 345/54, 345/87, 345 88- 89, 345/96, 345/204, 345/209, 345/212, 345/95, 348/674, 349/42
• US Class Current: 345/96
• CPC Class Codes: G09G 2310/0224 Details of interlacing
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• 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

Abstract

A display device including a liquid crystal display (LCD) device with an improved image quality is provided. The LCD includes a liquid crystal (LC) panel having horizontal lines and vertical lines arranged in a matrix configuration; a gate driver for supplying a scan signal to the horizontal lines; and a data driver inverting a polarity of interlace pixel data by a unit of at least two fields, converting the interlace pixel data every field according to a gamma voltage, and supplying the converted pixel data to the vertical lines.

Claims

1. A liquid crystal display device comprising:

a liquid crystal panel having horizontal lines and vertical lines arranged in a matrix configuration;

a controller for receiving interlace pixel data every frame and generating a control signal including a gate shift pulse signal, each frame including an odd field and an even field, and dummy pixel data being generated from the interlace pixel data at each field;

a polar signal generator for generating a unipolar signal and a bipolar signal in response to the gate shift pulse signal, the unipolar signal having one of a low voltage and a high voltage at each field, and a polarity of the bipolar signal being inverted by a unit of at least two fields;

a gamma voltage generator for changing positive and negative gamma voltages that have different value using the unipolar signal at each field, the positive and negative gamma voltage each increasing as much as a high voltage of the unipolar signal for an odd field and decreasing as much as a low voltage of the unipolar signal for an even field;

a gate driver for supplying a scan signal to the horizontal lines; and

a data driver for inverting polarities of the interlace pixel data and the dummy pixel data by the unit of at least two fields according to the bipolar signal, converting the interlace pixel data and the dummy pixel data into the changed positive gamma voltage or the changed negative gamma voltage from the gamma voltage generator for at least two fields, and supplying the changed gamma voltage to the vertical lines,

wherein the data driver gamma-converts the interlace pixel data according to the gamma voltage increases as much as the high voltage for the odd field and gamma-converts the dummy pixel data according to the gamma voltage decreases as much as the low voltage for the even field,

wherein the gamma voltage generator includes a positive polar gamma voltage generator and a negative polar gamma voltage generator,

wherein the positive gamma voltage generator changes the positive gamma voltage using the unipolar signal at each field, the positive gamma voltage increasing as much as a high voltage when the unipolar signal has the high voltage for the odd field and decreasing as much as a low voltage when the unipolar signal has the low voltage for the even field,

wherein the negative gamma voltage generator changes the negative gamma voltage using the unipolar signal at each field, the negative gamma voltage increasing as much as a high voltage when the unipolar signal has the high voltage for the odd field and decreasing as much as a low voltage when the unipolar signal has the low voltage for the even field.

2. A method of driving a liquid crystal display device comprising:

receiving interlace pixel data every frame, each frame including an odd field and an even field;

generating a control signal including a gate shift pulse signal;

generating dummy pixel data from the interlace pixel data at each field;

generating a unipolar signal and a bipolar signal in response to the gate shift pulse signal, the unipolar signal having one of a low voltage and a high voltage at each field, and a polarity of the bipolar signal being inverted by a unit of at least two fields;

changing positive and negative gamma voltages that have different value using the unipolar signal at each field, the positive and negative gamma voltage each increasing as much as a high voltage of the unipolar signal for an odd field and decreasing as much as a low voltage of the unipolar signal for an even field;

inverting polarities of the interlace pixel data and the dummy pixel data by the unit of at least two fields according to the bipolar signal;

converting the interlace pixel data and the dummy pixel data into the changed positive gamma voltage or the changed negative gamma voltage for at least two fields; and

supplying the changed gamma voltage to a liquid crystal panel,

wherein the gamma voltage increases as much as a high voltage is output for the odd field and the gamma voltage decreases as much as a low voltage is output for the even field,

wherein the positive gamma voltage increases as much as a high voltage when the unipolar signal has the high voltage for said interlace pixel data of the odd field and decreases as much as a low voltage when the unipolar signal has the low voltage for said dummy pixel data of the even field,

wherein the negative gamma voltage increases as much as a high voltage when the unipolar signal has the high voltage for said interlace pixel data of the odd field and decreases as much as a low voltage when the unipolar signal has the low voltage for said dummy pixel data of the even field.

3. The method according to claim 2, wherein the interlace pixel data and the dummy pixel data of the odd field is converted into the gamma voltage increases as much as a high voltage of the unipolar signal and the interlace pixel data and the dummy pixel data of the even field is converted into the gamma voltage decreases as much as a low voltage of the unipolar signal.