IP Library Granted Patent US 8,638,287
Granted Patent B2
US 8,638,287 · App. 12/003,489 · Granted Jan 28, 2014

Liquid crystal display device and method for driving the same

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Quick Facts
Patent No.
US 8,638,287
App. No.
12/003,489
Granted
Jan 28, 2014
Kind
B2
Abstract

Provided is a liquid crystal display device that can improve the image quality of a moving image. The liquid crystal display device includes a driver, a backlight unit, a first lamp driver, a second lamp driver, and a lamp driving controller. The liquid crystal panel divided is into at least three regions, and has a plurality of lamps arranged to correspond to each of the divided regions. Lamps of the lamps arranged in upper and lower regions of the liquid crystal panel are connected to each other. The first lamp driver controls on/off times of the lamps in the upper and lower regions of the liquid crystal panel. The second lamp driver controls on/off times of the lamps in the region excluding the upper and lower regions of the liquid crystal panel. The lamp driving controller controls the first and second lamp drivers using signals supplied from the driver.

Claims (39)

1. A liquid crystal display device comprising:

a driver for driving a liquid crystal panel;

a backlight unit including a plurality of lamps dividing the liquid crystal panel into three regions including a center region, an upper region and a lower region, and having lamps of the plurality of lamps arranged to correspond to each of the three regions, the lamps of the plurality of lamps corresponding to the upper and lower regions of the liquid crystal panel being connected to each other;

a first lamp driver for controlling on and off times of the lamps arranged in the upper and lower regions of the liquid crystal panel;

a second lamp driver for controlling on and off times of the lamps arranged in the center region of the three regions excluding the upper and lower regions of the liquid crystal panel; and

a lamp driving controller for controlling the first and second lamp drivers using signals supplied from the driver,

wherein the lamps in the center region of the liquid crystal panel are simultaneously driven,

wherein the lamps in the center region are turned on prior to turning on the lamps arranged in the upper and lower regions,

wherein the lamps in the upper and lower regions are simultaneously driven by the first lamp driver,

wherein the lamps arranged in the upper and lower regions are simultaneously turned on, and

wherein the lamps arranged in the center region are simultaneously turned on.

2. The liquid crystal display device according to claim 1 , wherein the lamp driving controller comprises:

a counter for receiving and counting a gate shift pulse signal to calculate a count value;

a first comparator for comparing the count value from the counter with a first reference value to generate a first comparison signal as a result of the comparison;

a second comparator for comparing the count value from the counter with a second reference value to generate a second comparison signal as a result of the comparison;

a first operator for performing logical operation on the first and second comparison signals to generate a first control signal; and

a second operator for performing logical operation on the first and second comparison signals to generate a second control signal, the second control signal having an inverse logic state from the first control signal.

3. The liquid crystal display device according to claim 2 , wherein the counter is initialized by a gate start pulse signal.

4. The liquid crystal display device according to claim 2 , wherein the counter counts a horizontal synchronization signal.

5. The liquid crystal display device according to claim 3 , wherein the counter is initialized by a vertical synchronization signal.

6. A method for driving a liquid crystal display device including: a driver for driving a liquid crystal panel; and a backlight unit having a plurality of lamps dividing the liquid crystal panel into three regions including an upper region, a center region and a lower region, lamps of plurality of lamps arranged to correspond to each of the three regions, the lamps of the lamps corresponding to the upper and lower regions of the liquid crystal panel being connected to each other, the method comprising:

generating a control signal for controlling on and off times of the lamps arranged in the upper and lower regions of the liquid crystal panel using a signal supplied from the driver, and a control signal for controlling on and off times of the lamps arranged in the center region of the three regions excluding the upper and lower regions of the liquid crystal panel;

turning on the lamps arranged in the center region excluding the upper and lower regions of the liquid crystal panel;

turning on the lamps arranged in the upper and lower regions of the liquid crystal panel; and

displaying an image on the liquid crystal panel as the plurality of lamps are turned on,

wherein the lamps in the center region of the liquid crystal panel are simultaneously driven,

wherein the lamps in the center region are turned on prior to turning on the lamps arranged in the upper and lower regions,

wherein the lamps in the upper and lower regions are simultaneously driven by the first lamp driver,

wherein the lamps arranged in the upper and lower regions are simultaneously turned on, and

wherein the lamps arranged in the center region are simultaneously turned on.

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

counting a received gate shift pulse signal to calculate the count value;

comparing the count value with a first reference value to generate a first comparison signal as a result of the comparison result;

comparing the count value with a second reference value to generate a second comparison signal as a result of the comparison result;

performing a logical operation on the first and second comparison signals to generate a first control signal; and

performing a logical operation on the first and second comparison signals to generate a second control signal having a logic state that is the inverse of a logic state of the first control signal.

8. The method according to claim 7 , wherein a counter for counting the gate shift pulse signal is initialized by a gate start pulse signal.

9. The method according to claim 7 , wherein the calculating of the count value comprises counting a horizontal synchronization signal.

10. The method according to claim 7 , wherein a counter for counting the gate shift pulse signal is initialized by a vertical synchronization signal.

Assignments (2)
CHANGE OF NAME Recorded Oct 17, 2008
From: LG. PHILIPS LCD CO., LTD.
To: LG DISPLAY CO., LTD.
Reel/Frame 021773/0029 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 26, 2007
From: KIM, KI DUK
To: LG.PHILIPS LCD CO., LTD.
Reel/Frame 020338/0732 →