Apparatus and method for driving liquid crystal display device

• US 20060007103A1
• Filed: 05/27/2005
• Published: 01/12/2006
• Est. Priority Date: 05/28/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Kim, Hong Chul, Hong, Hee Jung, Oh, Eui Yeol, Park, Hee Jeong
• Granted Patent: US 7,573,447 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 2201/52 RGB geometrical arrangements
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

An apparatus and method for driving a light source of a liquid crystal display device are provided. The apparatus includes a liquid crystal display panel, a backlight unit including a plurality of light emitting diodes (LEDs) to irradiating light to the liquid crystal display panel, and a driver to selectively drive the LEDs and selectively control a brightness of light generated by the LEDs.

Claims

1. An apparatus for driving a liquid crystal display device, the apparatus comprising:

a liquid crystal display panel having at least two division areas;

a light generator including at least one light emitting diode (LED) and irradiating light to each division area of the liquid crystal display panel; and

a driver to control a brightness of the light emitted by the LED, in accordance with a peak value of gray level of each division area.

2. The apparatus according to claim 1, wherein the at least one LED includes:

at least one white LED;

or

red, green, and blue LEDs.

3. The apparatus according to claim 2, wherein the red, green, and blue LEDs include any one of the following:

red-green-blue LEDs, red-green-green-blue LEDs, or red-green-blue-blue LEDs.

4. The apparatus according to claim 2, wherein the red, green and blue LEDs are arranged vertically and horizontally in certain order.

5. The apparatus according to claim 1, wherein the driver:

adjusts a duty ratio of a signal being supplied to the LED in accordance with a reference brightness of the liquid crystal display panel during a scanning period before a picture implementing period of the liquid crystal display panel, and changes an amplitude of the signal to correspond to the reference brightness;

or

adjusts the amplitude of the signal being supplied to the LED in accordance with the reference brightness of the liquid crystal display panel, and changes the duty ratio of the signal to correspond to the reference brightness.

6. The apparatus according to claim 1, further comprising:

a timing controller supplied with the peak value of the gray level of each division area to generate a control signal corresponding to the peak value and to supply the control signal to the driver.

7. The apparatus according to claim 6, wherein the driver includes:

a pulse width modulation (PWM) controller arranged between the timing controller and the LED; and

a switch arranged between the PWM controller and the LED to control on-off of the LED.

8. The apparatus according to claim 7, wherein the PWM controller is connected to a light emitting diode group formed by at least one LED, to adjust a strength of current generated by the timing controller.

9. A liquid crystal display device comprising:

a liquid crystal display panel;

a backlight unit including a plurality of light emitting diodes (LEDs) to irradiating light to the liquid crystal display panel; and

a driver to selectively drive the LEDs and selectively control a brightness of light generated by the LEDs.

10. The device according to claim 9, wherein the LEDs are one of the following:

white LEDs;

or

a combination of red, green, and blue LEDs.

11. The device according to claim 9, wherein the LEDs are arranged in one of the following manners:

a sequence of red LED, green LED, green LED, and blue LED;

or

a sequence of red LED, green LED, blue LED, and blue LED.

12. The device according to claim 9, wherein the driver adjusts a duty ratio and/or an amplitude of a basic pulse signal to control the brightness of the light generated by one or more of the LEDs.

13. The device according to claim 9, wherein the plurality of LEDs are arranged in a matrix configuration.

14. A method for driving a liquid crystal display device including a liquid crystal display panel and a light generator, the method comprising:

dividing the liquid crystal display panel into at least two division areas; and

controlling, in accordance with a peak value of gray level of each division area, the light generator including at least one light emitting diode (LED) to generate and irradiate light to each division area.

15. The method according to claim 14, wherein in the controlling step, the at least one LED includes:

at least one white LED;

or

red, green, and blue LEDs arranged in certain order.

16. The method according to claim 15, wherein the red, green, and blue LEDs include any one of the following:

red-green-blue LEDs, red-green-green-blue LEDs, or red-green-blue-blue LEDs.

17. The method according to claim 14, wherein the controlling step includes:

adjusting a duty ratio of a signal being supplied to the LED in accordance with a reference brightness of the liquid crystal display panel during a scanning period before a picture implementing period of the liquid crystal display panel, and changing an amplitude of the signal to correspond to the reference brightness;

or

adjusting the amplitude of the signal being supplied to the LED in accordance with the reference brightness of the liquid crystal display panel, and changing the duty ratio of the signal to correspond to the reference brightness.

18. The method according to claim 14, wherein the controlling step includes:

calculating the peak value of the gray level of each division area; and

generating a control signal corresponding to the peak value.

19. The method according to claim 18, wherein the controlling step further includes:

Generating a pulse signal according to the control signal; and

selectively controlling the LED using the pulse signal.

20. The method according to claim 14, wherein the at least LED includes a plurality of LEDs arranged in a matrix configuration, and the controlling step includes:

dividing the plurality of LEDs into a plurality of LED groups; and

selectively driving each of the LED groups.