Liquid crystal display device and driving method thereof

• US 7,385,583 B2
• Filed: 09/30/2004
• Issued: 06/10/2008
• Est. Priority Date: 10/21/2003
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Kim, Hyun Seok, Kim, Myung Hoon
• Primary Examiner(s): Dinh; Duc Q
• Application Number:
  US10/954,944
• Publication Number:
  US 20050083294A1
• Time in Patent Office: 1,349 Days
• Field of Search: 345/102, 345/87, 345/204, 345/211, 345/690
• US Class Current: 345/102
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines

Abstract

An apparatus and a method of driving a liquid crystal display device includes generating a first control signal and a second control signal using a vertical synchronization signal and a horizontal synchronization signal, respectively; applying a scan pulse to gate lines depending on the first control signal; applying data to source lines depending on the second control signal; and driving a backlight unit in accordance with a change of state of at least one of the first control signal and the second control signal.

Claims

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

generating a first control signal having a change of state at a time delay with respect to a vertical synchronization signal;

applying a scan pulse to gate lines in response to the change of state of the first control signal;

applying data to source lines in response to a change of state of a second control signal;

controlling a backlight unit having a plurality of lamps depending on the change of state of at least one of the first control signal and the second control signal; and

wherein a turn-on time point of a first lamp of the lamps is synchronized with the change of state of at least one of the first control signal and the second control signal.

2. The driving method of a liquid crystal display device according to claim 1, wherein the act of controlling a backlight unit comprises controlling a backlight unit sequentially depending on the change of state of at least one of the first control signal and the second control signal.

3. The driving method of a liquid crystal display device according to claim 1, wherein the change of state of the first or the second control signal is a rising edge of a pulse.

4. The driving method of a liquid crystal display device according to claim 1, wherein the change of state of the first or the second control signal is a falling edge of a pulse.

5. The driving method of a liquid crystal display device according to claim 1, wherein the scan pulse is sequentially applied to a group of gate lines.

6. The driving method of a liquid crystal display device according to claim 1, wherein the second control signal comprises a horizontal synchronization signal.

7. The driving method of a liquid crystal display device according to claim 1, wherein the second control signal comprises a source start pulse.

8. The driving method of a liquid crystal display device according to claim 1, wherein the change of state of the second control signal is time delayed with respect to the vertical synchronization signal.

9. The driving method of a liquid crystal display device according to claim 1, wherein the time delay is greater than or about equal to about a pixel capacitor charging time.

10. The driving method of a liquid crystal display device according to claim 1, wherein the first lamp is turned on depending on the change of state of at least one of the first control signal and the second control signal.

11. The driving method of a liquid crystal display device according to claim 1, wherein the first lamp is turned on for a predetermined period of time.

12. The method according to claim 1, wherein controlling the backlight unit comprises:

determining a turn-on time point of the first lamp on the basis of the change of state of the first or the second control signal;

lighting the first lamp during a lighting duration; and

lighting a second lamp of the plurality of lamps after the lighting duration of the first lamp.

13. The driving method of a liquid crystal display device according to claim 12, wherein the lighting duration is a predetermined period of time.

14. The driving method of a liquid crystal display device according to claim 12, wherein the lighting duration is a predetermined number of changes of state of the second control signal.

15. The driving method of a liquid crystal display device according to claim 12, wherein the turn-on time is delayed with respect to the vertical synchronization signal by at least approximately a pixel capacitor charging time.

16. The driving method of a liquid crystal display device according to claim 12, where the change of state of the second control signal is delayed with respect to the vertical synchronization signal.

17. A liquid crystal display device comprising:

a LCD panel, including gate and data lines;

a backlight unit disposed behind the LCD panel;

an electronics unit, adapted to receive signals including data and a vertical synchronization signal, the electronics unit outputting a first control signal having a time delay with respect to the vertical synchronization signal, and a second control signal associated with a horizontal synchronization signal;

a gate driver for applying a scan pulse to gate lines depending on a change of state of the first control signal;

a source driver for applying data to source lines depending on a change of state of the second control signal;

a driving unit for driving the backlight unit having a plurality of lamps in accordance with the change of state of the first control signal or the second control signal; and

wherein a turn-on time point of a first lamp of the lamps is synchronized with the change of state of at least one of the first control signal and the second control signal.

18. The liquid crystal display device according to claim 17, wherein the scan pulse is sequentially applied to a group of gate lines.

19. The liquid crystal display device according to claim 17, wherein the backlight unit comprises a plurality of lamps.

20. The liquid crystal display device according to claim 19, wherein each lamp is turned on for a predetermined time.

21. The liquid crystal display device according to claim 20, wherein the plurality of lamps are turned on for a varying predetermined times.

22. The liquid crystal display device according to claim 19, wherein the first lamp of the plurality of lamps is turned on based on the change of state of the first control signal or the second control signal.

23. The liquid crystal display device according to claim 22, wherein a second lamp of the plurality of lamps is turned on after the change of state of the first control signal and a predetermined number of changes of state of the second control signal.

24. The liquid crystal display device according to claim 17, wherein the LCD panel comprises pixels, each pixel having a capacitor, the capacitor having a charging time constant, and wherein the change of state of the first control signal with respect to the vertical synchronization signal by a time at least equal to approximately a pixel capacitor charging time constant.

25. The liquid crystal display device according to claim 24, wherein the LCD panel comprises pixels, each pixel having a capacitor, the capacitor having a charging time constant, and wherein the change of state of the second control signal with respect to the horizontal synchronization signal by a time at least equal to approximately a pixel capacitor charging time constant.

26. The liquid crystal display device according to claim 17, wherein the LCD panel comprises pixels, each pixel having a capacitor, the capacitor having a charging time constant, and wherein the change of state of the second control signal with respect to the horizontal synchronization signal by a time at least equal to approximately a pixel capacitor charging time constant.

27. The liquid crystal display device according to claim 22, wherein the first of the plurality of lamps is disposed behind a first predetermined number of gate lines, and the second of the plurality of lamps is disposed behind a second predetermined number of gate lines, and the first lamp is turned on depending on a change of state o the first control signal or the second control signal applied to a first of the second predetermined number of gate lines.

28. The liquid crystal display device according to claim 22, wherein a second lamp is turned on after a predetermined time.

29. The liquid crystal display device according to claim 17, wherein the change of state of the first or the second control signal is a rising edge of a pulse.

30. The liquid crystal display device according to claim 17, wherein the change of state of the first or the second control signal is a falling edge of a pulse.

31. The liquid crystal display device according to claim 17, wherein the control signal is a first gate start pulse following the start of the vertical synchronization signal.

32. The liquid crystal display device according to claim 17, wherein the first control signal comprises a gate start pulse following the start of the vertical synchronization signal.

33. The liquid crystal display device according to claim 17, wherein the second control signal comprises a source start pulse following the start of the horizontal synchronization signal.