Liquid crystal display having common voltage regenerator and driving method thereof

• US 8,310,427 B2
• Filed: 07/14/2008
• Issued: 11/13/2012
• Est. Priority Date: 07/13/2007
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: Chi Mei Innolux Corporation (InnoLux Corporation)
• Inventors: Sheu, Yi-Zhong
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): RABINDRANATH, ROY P
• Application Number:
  US12/218,362
• Publication Number:
  US 20090015528A1
• Time in Patent Office: 1,583 Days
• Field of Search: 345/92
• US Class Current: 345/92
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

An exemplary liquid crystal display includes a liquid crystal panel, a common voltage generator, and a common voltage regenerator. The liquid crystal panel includes liquid crystal capacitors and storage capacitors. Each liquid crystal capacitor includes a common electrode. Each storage capacitor includes a storage electrode. The common voltage generator is configured to provide a common voltage to the storage electrode. The common voltage regenerator is configured to receive a common feedback voltage from the storage electrode, generate a common regenerative voltage according to the common feedback voltage, and provide the common regenerative voltage to the common electrode.

Claims

1. A liquid crystal display comprising:

a liquid crystal panel comprising;

a first substrate including a common electrode layer formed thereon;

a second substrate opposite to the first substrate; and

a liquid crystal layer sandwiched between the first and second substrates;

a plurality of data lines and a plurality of gate lines provided on the second substrate and crossing each other to define a plurality of pixel units, each pixel unit comprising a liquid crystal capacitor, and a storage capacitor, each liquid crystal capacitor comprising a pixel electrode for receiving gradation voltages applied by a corresponding one of the data lines, the common electrode layer opposite to the pixel electrode and the liquid crystal layer sandwiched therebetween; and

each storage capacitor comprising the pixel electrode, a storage electrode opposite to the pixel electrode and an insulating material sandwiched therebetween; and

a first common voltage line and a second common voltage line formed at two opposite sides of the second substrate for sandwiching the plurality of pixel units, both of the first and second common voltage lines connected to each storage electrode;

a common voltage generator configured to provide a common voltage to the storage electrode via the first common voltage line;

a common voltage regenerator configured to receive a voltage on the second common voltage line as a common feedback voltage, generate a common regenerative voltage via a common line according to the common feedback voltage, and provide the common regenerative voltage to the common electrode layer; and

the common line located on the second substrate and electrically connected to the common electrode layer via silver paste, the common regenerative voltage being applied to the common electrode layer via the common line and the silver paste in sequence;

wherein the common line is located between a first edge of the second substrate and the first common voltage line, and between a second edge of the second substrate and the second common voltage line.

2. The liquid crystal display of claim 1, wherein the common voltage regenerator comprises a common feedback voltage input, a common voltage input, and a common regenerative voltage output, the common feedback voltage input being electrically connected to the storage electrode via the second common voltage line, the common voltage input being electrically connected to the common voltage generator, and the common regenerative voltage output being electrically connected to the common line.

3. The liquid crystal display of claim 2, wherein the common voltage regenerator further comprises an operational amplifier, a capacitor, a first resistor, and a second resistor, the common feedback voltage input being electrically connected to an inverting input of the operational amplifier via the capacitor and the first resistor, an output of the operational amplifier being electrically connected to the common regenerative voltage output, the common regenerative voltage output being also electrically connected to the inverting input of the operational amplifier via the second resistor, and the common voltage input being electrically connected to a non-inverting input of the operative amplifier.

4. The liquid crystal display of claim 1, wherein the common feedback voltage received by the common voltage regenerator comprises a plurality of ripples.

5. The liquid crystal display of claim 4, wherein the common regenerative voltage generated by the common voltage regenerator comprises a plurality of ripples of phase opposite to ripples of the common feedback voltage.

6. The liquid crystal display of claim 5, wherein the ripples of the common regenerative voltage have the same amplitude as the ripples of the common feedback voltage.

7. The liquid crystal display of claim 1, wherein the common voltage provided by the common voltage generator is a 5v direct current voltage.

8. The liquid crystal display of claim 1, wherein the common line is formed along four sides of the second substrate of the liquid crystal panel.

9. The liquid crystal display of claim 8, wherein the common line is divided into four sections corresponding to the four sides of the second substrate of the liquid crystal panel, and the liquid crystal display further comprises three common voltage regenerators, which, together with the original common voltage regenerator, are configured to provide common regenerative voltages to the four sections of the common line.

10. The liquid crystal display of claim 9, wherein the common regenerative voltages provided by the four common voltage regenerators are different from each other.

11. The liquid crystal display of claim 1, wherein the first and second common voltage lines are parallel to the data lines.

12. A method for driving a liquid crystal display, the liquid crystal display comprising a liquid crystal panel, a common voltage generator, and a common voltage regenerator, the liquid crystal panel comprising a first substrate including a common electrode layer formed thereon, a second substrate opposite to the first substrate, and a liquid crystal layer sandwiched between the first and second substrates, a plurality of data lines and a plurality of gate lines provided on the second substrate and crossing each other to define a plurality of pixel units, each pixel unit comprising a liquid crystal capacitor and a storage capacitor, each liquid crystal capacitor comprising a pixel electrode for receiving gradation voltages applied by a corresponding one of the data lines, the common electrode layer opposite to the pixel electrode, and the liquid crystal layer sandwiched therebetween, and each storage capacitor comprising the pixel electrode, a storage electrode opposite to the pixel electrode, and an insulating material sandwiched therebetween, wherein the liquid crystal panel further comprises a first common voltage line and a second common voltage line formed at two opposite sides of the second substrate for sandwiching the plurality of pixel units, both of the first and second common voltage lines connected to each storage electrode, the method comprising:

the common voltage generator providing a common voltage to the storage electrode via the first common line;

the common voltage regenerator receiving a voltage on the second common line as a common feedback voltage;

the common voltage regenerator generating a common regenerative voltage via a common line according to the common feedback voltage, and providing the common regenerative voltage to the common electrode layer; and

the common line via which the common voltage regenerator provides the common regenerative voltage to the common electrode layer is connected electrically to the common electrode layer via silver paste, the common regenerative voltage comprising ripples;

wherein the common line is located between a first edge of the second substrate and the first common voltage line, and between a second edge of the second substrate and the second common voltage line.

13. The method of claim 12, wherein the common feedback voltage-comprises ripples.

14. The method of claim 12, wherein the ripples of the common regenerative voltage have a phase opposite to, and amplitude the same as, ripples of the common feedback voltage.

15. A liquid crystal display comprising:

a liquid crystal panel comprising;

a first substrate;

a second substrate opposite to the first substrate;

a liquid crystal layer sandwiched between the first and second substrates;

a plurality of data lines parallel to each other along a first direction;

a plurality of gate lines parallel to each other along a second direction perpendicular to the first direction, thereby defines an array including a plurality of rows and a plurality of columns;

a plurality of conductive lines parallel to the gate lines;

a plurality of common electrodes and a plurality of storage electrodes, the storage electrodes at each row rows connected to a same conductive line; and

a first common voltage line and a second common voltage line formed at two opposite sides of the second substrate for sandwiching the array, the first common voltage line connected to one end of the plurality of conductive lines, and the second common voltage line connected to the other end of the plurality of connective lines;

a common voltage generator configured to provide a common voltage to the storage electrode via the first common voltage line and the conductive lines;

a common voltage regenerator connected to the second common voltage line and configured to receive a voltage on the second common voltage line as a common feedback voltage, generate a common regenerative voltage via a common line according to the common feedback voltage, and provide the common regenerative voltage to the common electrode; and

the common line via which the common voltage generator is connected electrically to the common electrode is connected electrically to the common electrode layer via silver paste;

wherein the common line is located between a first edge of the second substrate and the first common voltage line, and between a second edge of the second substrate and the second common voltage line.

16. The liquid crystal display of claim 15, wherein the common feedback voltage and the common regenerative voltage each have ripples, the ripples of the common regenerative voltage having a phase opposite to the ripples of the common feedback voltage, and amplitude the same as the ripples of the common feedback voltage.