Liquid crystal display device and driving method thereof

• US 7,728,804 B2
• Filed: 05/30/2003
• Issued: 06/01/2010
• Est. Priority Date: 12/30/2002
• Status: Expired due to Fees

• Current Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Do Sung, Park, Sung Chul
• Primary Examiner(s): Tran; Henry N
• Application Number:
  US10/448,130
• Publication Number:
  US 20040125066A1
• Time in Patent Office: 2,559 Days
• Field of Search: 345/92, 345/93, 345/87, 345/90, 345/94, 345/96, 345 98-100, 345/209, 345/211, 345/88, 345/89, 345/206, 349/123, 349/124, 349/128, 349/134, 349/139, 349/155, 349/136, 349/177, 349/179
• US Class Current: 345/90
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• 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 liquid crystal display device includes a thin film transistor arranged at crossings of gate lines and data lines; a pixel electrode connected to each thin film transistor; a common electrode arranged on a second substrate; a layer of liquid crystal material provided between the first and second substrates; a protrusion arranged on the common electrode for controlling an orientation of the liquid crystal molecules within the layer of liquid crystal material; and a common voltage generator applying an AC common voltage to the common electrode, wherein a polarity of the common voltage is inverted every predetermined period.

Claims

1. A liquid crystal display device, comprising:

a first substrate;

a plurality of gate lines on the first substrate;

a plurality of data lines on the first substrate, crossing the plurality of gate lines;

thin film transistors arranged at crossings of the plurality of gate and data lines;

pixel electrodes connected to the thin film transistors;

a second substrate;

a common electrode on the second substrate;

a layer of liquid crystal material between the first and second substrates;

a protrusion on the common electrode for controlling an orientation direction of the liquid crystal layer so as to form different orientation directions in the liquid crystal layer;

a common voltage generator applying a common voltage to the common electrode, wherein the common voltage is an AC voltage having a predetermined period;

a data driver that applies a pixel voltage signal to the plurality of data lines;

a gate driver for driving the plurality of gate lines; and

a timing controller for controlling the gate and data drivers and for applying a pixel data signal to the data driver;

wherein a potential difference between the common voltage and the pixel voltage signal is set to a predetermined value to control the orientation of liquid crystal molecules arranged proximately to a projected area of the common electrode, wherein a polarity of the pixel voltage signal is inverted every horizontal period and frame period, and a polarity of the common voltage is inverted every horizontal period and frame period,

wherein the layer of liquid crystal material is driven according to a two-domain twist nematic mode, and

wherein a potential difference between the common voltage and a positive pixel voltage signal is about 10 V and a potential difference between the common voltage and a negative pixel voltage signal is about 10 V,

wherein a left/right viewing angle of the liquid crystal display device is 80°

/80°

while a top/bottom viewing angle is 80°

/80°

,

wherein the thin film transistors (TFTs) is formed of polycrystalline silicon.

2. The device according to claim 1, wherein the portions of the layer of liquid crystal material are aligned in different directions within domain.

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

providing a first substrate;

providing a plurality of gate lines on the first substrate;

providing a plurality of data lines on the first substrate and crossing the plurality of gate lines;

forming thin film transistors at crossings of the plurality of gate and data lines;

forming pixel electrodes connected to the thin film transistors;

providing a second substrate;

forming a common electrode on the second substrate;

forming a protrusion on the common electrode;

forming a liquid crystal layer between the first and second substrates, wherein the protrusion is capable of controlling an orientation direction of the liquid crystal layer so as to form different orientation directions in the liquid crystal layer;

applying a pixel voltage signal to the pixel electrodes, wherein a polarity of the pixel voltage signal is periodically inverted; and

applying a common voltage to the common electrode, wherein the common voltage has a predetermined potential difference from the pixel voltage signal to control the orientation of liquid crystal molecules arranged proximately to a projected area of the common electrode, wherein a polarity of the pixel voltage signal is inverted every horizontal period and frame period, and a polarity of the common voltage is inverted every horizontal period and frame period,

wherein the layer of liquid crystal material is driven according to a two-domain twist nematic mode, and

wherein a potential difference between the common voltage and a positive pixel voltage signal is about 10 V and a potential difference between the common voltage and a negative pixel voltage signal is about 10 V,

wherein a left/right viewing angle of the liquid crystal display device is 80°

/80°

while a top/bottom viewing angle is 80°

/80°

,

wherein the thin film transistors (TFTs) is formed of polycrystalline silicon.

4. The method according to claim 3, wherein portions of the layer of liquid crystal material are aligned in different directions within each domain.

5. A liquid crystal display device, comprising:

a liquid crystal display panel, the liquid crystal display panel including a plurality of data lines and a common electrode, wherein the liquid crystal display panel has a liquid crystal layer having different orientation directions;

thin film transistors arranged at crossings the data lines and a plurality of gate lines, an active semiconductor layer of the thin film transistors including polycrystalline silicon material;

a data driver for applying a pixel voltage signal to the plurality of data lines according to a predetermined driving scheme; and

a common voltage generator for applying a common voltage to the common electrode, wherein a polarity of the common voltage is inverted corresponding to the polarity of the pixel voltage signal based on the predetermined driving scheme to control the orientation of liquid crystal molecules arranged proximately to a projected area of the common electrode, wherein the predetermined driving scheme includes a line inversion scheme and a frame inversion scheme,

wherein the liquid crystal layer is driven according to a two-domain twist nematic mode,

wherein a potential difference between the common voltage and a positive pixel voltage signal is about 10 V and a potential difference between the common voltage and a negative pixel voltage signal is about 10 V,

wherein a left/right viewing angle of the liquid crystal display device is 80°

/80°

while a top/bottom viewing angle is 80°

/80°

,

wherein the thin film transistors (TFTs) is formed of polycrystalline silicon.