LCD and backlight module driving device and method thereof

• US 8,519,939 B2
• Filed: 06/09/2008
• Issued: 08/27/2013
• Est. Priority Date: 04/22/2008
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Li, Yueh-Han, Hsu, Po-Tang, Ko, Chien-Ming, Yu, Ching-Chou
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): SEYOUM, TSEGAYE H
• Application Number:
  US12/135,222
• Publication Number:
  US 20090262064A1
• Time in Patent Office: 1,905 Days
• Field of Search: 345/102
• 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 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2330/06 Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation
• 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 LCD and a backlight module driving device and a method thereof are provided. The method is adapted to drive at least one backlight unit in a backlight module. The backlight unit is used for supplying a surface light source to an N^th area pixel of the LCD panel, where N is a positive integer. The method includes the following steps of first calculating a time of the N^th area pixel under a stable state in a frame period and then providing a control signal to drive the backlight unit when the N^th area pixel is under the stable state in the frame period.

Claims

1. A backlight module driving method, adapted to drive at least one backlight unit in a backlight module, wherein the backlight unit provides a surface light source to an N^th area pixel of a liquid crystal display (LCD) panel of an LCD, where N is a positive integer, the backlight module driving method comprising:

calculating a total time of the N^th area pixel under a stable state in a frame period; and

providing a control signal to drive the backlight unit within the total time of the N^th area pixel under the stable state in the frame period, so as to make the backlight unit provide the surface light source to the N^th area pixel,

wherein a center position of a turn-on time of the control signal aligns with a center position of the total time of the N^th area pixel under the stable state in the frame period, and the turn-on time of the control signal substantially does not extend into a transition state of the N^th area pixel and an (N+1)^th area pixel of the LCD panel,

wherein the (N+1)^th area pixel is close to the N^th area pixel.

2. The backlight module driving method according to claim 1, wherein the backlight unit comprises a plurality of sub backlight units, and the backlight module driving method further comprising:

providing a plurality of sub control signals to respectively drive the sub backlight units according to the center position of the total time of the N^th area pixel under the stable state in the frame period, wherein an i^th sub backlight unit is used to provide a surface light source to an i^th area pixel in the N^th area pixel, where i is a positive integer.

3. The backlight module driving method according to claim 2, wherein center positions of turn-on times of the sub control signals align with the center position of the total time of the N^th area pixel under the stable state in the frame period, and the turn-on times of the sub control signals substantially do not extend into a transition state of the N^th area pixel and an (N+1)^th area pixel of the LCD panel.

4. The backlight module driving method according to claim 2, wherein the sub control signals have different turn-on times.

5. The backlight module driving method according to claim 1, wherein a frequency of the control signal is the same as a frame rate of the LCD.

6. The backlight module driving method according to claim 1, wherein a turn-on time of the control signal is shorter than the total time of the N^th area pixel under the stable state in the frame period.

7. The backlight module driving method according to claim 1, wherein a time period between an ending time point of the N^th area pixel under a transition state in a current frame period and a turn-on time point of the control signal is equal to a time period between a turn-off time point of the control signal and an starting time point of the N^th area pixel under a transition state in a next frame period.

8. A backlight module driving device, adapted to drive at least one backlight unit in a backlight module, wherein the backlight unit provides a surface light source to an N^th area pixel of an LCD panel of an LCD, where N is a positive integer, the backlight module driving device comprising:

a calculation unit, used for calculating a total time of the N^th area pixel under a stable state in a frame period; and

a driving unit, coupled to the calculation unit and the backlight module, for providing a control signal to drive the backlight unit within the total time of the N^th area pixel under the stable state in the frame period, so as to make the backlight unit provide the surface light source to the N^th area pixel,

wherein a center position of a turn-on time of the control signal aligns with a center position of the total time of the N^th area pixel under the stable state in the frame period, and the turn-on time of the control signal substantially does not extend into a transition state of the N^th area pixel and an (N+1)^th area pixel of the LCD panel, wherein the (N+1)^th area pixel is close to the N^th area pixel.

9. The backlight module driving device according to claim 8, wherein the backlight unit comprises a plurality of sub backlight units, and an i^th sub backlight unit is used to provide a surface light source to an i^th area pixel in the N^th area pixel, where i is a positive integer.

10. The backlight module driving device according to claim 9, wherein the driving unit further provides a plurality of sub control signals to respectively drive the sub backlight units according to the center position of the total time of the N^th area pixel under the stable state in the frame period.

11. The backlight module driving device according to claim 10, wherein center positions of turn-on times of the sub control signals align with the center position of the total time of the N^th area pixel under the stable state in the frame period, and the turn-on times of the sub control signals substantially do not extend into a transition state of the N^th area pixel and an (N+1)^th area pixel of the LCD panel.

12. The backlight module driving device according to claim 11, wherein the sub control signals have different turn-on times.

13. The backlight module driving device according to claim 8, wherein a frequency of the control signal is the same as a frame rate of the LCD.

14. The backlight module driving device according to claim 8, wherein a turn-on time of the control signal is shorter than the total time of the N^th area pixel under the stable state in the frame period.

15. The backlight module driving device according to claim 8, wherein a time period between an ending time point of the N^th area pixel under a transition state in a current frame period and a turn-on time point of the control signal is equal to a time period between a turn-off time point of the control signal and an starting time point of the N^th area pixel under a transition state in a next frame period.

16. An LCD, comprising:

an LCD panel;

a backlight module, comprising at least one backlight unit which provides a surface light source to an N^th area pixel of the LCD panel, where N is a positive integer; and

a backlight module driving device, coupled to the backlight module, for calculating a total time of the N^th area pixel under a stable state in a frame period, and thus providing a control signal to drive the backlight unit within the total time of the N^th area pixel under the stable state in the frame period, so as to make the backlight unit provide the surface light source to the N^th area pixel,

wherein a center position of a turn-on time of the control signal aligns with a center position of the total time of the N^th area pixel under the stable state in the frame period, and the turn on time of the control signal substantially does not extend into a transition state of the N^th area pixel and an (N+1)^th area pixel of the LCD panel,

wherein the (N+1)^th area pixel is close to the N^th area pixel.

17. The LCD according to claim 16, wherein the backlight module driving device comprises:

a calculation unit, used to calculate the total time of the N^th area pixel under the stable state in the frame period; and

a driving unit, coupled to the calculation unit and the backlight module, for providing the control signal to drive the backlight unit within the total time of the N^th area pixel under the stable state in the frame period.

18. The LCD according to claim 17, wherein the backlight unit comprises a plurality of sub backlight units and an i^th sub backlight unit is used to provide a surface light source to an i^th area pixel in the N^th area pixel, where i is a positive integer.

19. The LCD according to claim 18, wherein the driving unit further provides a plurality of sub control signals to respectively drive the sub backlight units according to the center position of the total time of the N^th area pixel under the stable state in the frame period.

20. The LCD according to claim 19, wherein center positions of turn-on times of the sub control signals align with the center position of the total time of the N^th area pixel under the stable state in the frame period, and the turn-on times of the sub control signals substantially do not extend into a transition state of the N^th area pixel and an (N+1)^th area pixel of the LCD panel.

21. The LCD according to claim 20, wherein the sub control signals have different turn-on times.

22. The LCD according to claim 16, wherein a frequency of the control signal is the same as a frame rate of the LCD.

23. The LCD according to claim 16, wherein a turn-on time of the control signal is shorter than the total time of the N^th area pixel under the stable state in the frame period.

24. The LCD according to claim 16, wherein a time period between an ending time point of the N^th area pixel under a transition state in a current frame period and a turn-on time point of the control signal is equal to a time period between a turn-off time point of the control signal and an starting time point of the N^th area pixel under a transition state in a next frame period.

25. A backlight module driving method, adapted to drive at least one backlight unit in a backlight module, wherein the backlight unit provides a surface light source to an N^th area pixel of an LCD panel of an LCD, where N is a positive integer, the backlight module driving method comprising:

calculating a total time of the N^th area pixel under a stable state in a frame period; and

providing a control signal to drive the backlight unit when the N^th area pixel is under the stable state in the frame period,

wherein a frequency of the control signal is the same as a frame rate of the LCD,

wherein a center position of a turn-on time of the control signal aligns with a center position of the total time of the N^th area pixel under the stable state in the frame period, and the turn-on time of the control signal substantially does not extend into a transition state of the N^th area pixel and an (N+1)^th area pixel of the LCD panel,

where the (N+1)^th atrea pixel is close to the N^th area pixel.