Backlight driving method

• US 7,256,555 B2
• Filed: 06/29/2005
• Issued: 08/14/2007
• Est. Priority Date: 12/28/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Jin, Hyun-Suk, Kim, In-Jue, Lee, Deuk-Su
• Primary Examiner(s): TRAN, THUY V
• Application Number:
  US11/168,370
• Publication Number:
  US 20060139298A1
• Time in Patent Office: 776 Days
• Field of Search: 315/161, 315/291, 315/299, 315/307, 315/312, 315/324, 315/360, 345/87, 345/102
• US Class Current: 315/291
• 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 2320/0633 by amplitude modulation of the brightness of the illumination source
• 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

A method of driving a backlight unit is provided. The backlight includes a plurality of lamps sequentially turned on/off. Each of the plurality of lamps is periodically turned on for a predetermined period. The method includes applying a first lamp current to one of the plurality of lamps for a first time period within the predetermined period so that the one of the plurality of lamps emits light with a first brightness, and applying a second lamp current to the one of the plurality of lamps for a second time period within the predetermined period so that the one of the plurality of lamps emits light with a second brightness.

Claims

1. A method of driving a backlight unit, the backlight unit including a plurality of lamps sequentially turned on/off, each of the plurality of lamps being periodically turned on for a predetermined period, the method comprising:

applying a first lamp current to one of the plurality of lamps for a first time period within the predetermined period so that the one of the plurality of lamps emits light with a first brightness; and

applying a second lamp current to the one of the plurality of lamps for a second time period within the predetermined period so that the one of the plurality of lamps emits light with a second brightness,

wherein the first time period includes a first time segment and a second time segment, and the first time segment and the second time segment are separated by the second time period.

2. The method according to claim 1, wherein the second lamp current is greater than the first lamp current.

3. The method according to claim 1, wherein the second brightness is higher than the first brightness.

4. The method according to claim 1, wherein the second time period is shorter than the first time period.

5. The method according to claim 4, wherein the plurality of lamps include a first lamp and a second lamp adjacent to the first lamp, the predetermined period of the first lamp overlapping with the predetermined period of the second lamp.

6. The method according to claim 1, wherein the first lamp current is less than about 6 milli-amperes (mA) and the second lamp current is more than about 6 milli-amperes (mA).

7. A method of driving a backlight unit of a liquid crystal display device, the liquid crystal display device including the backlight unit, first and second substrates facing each other, and a liquid crystal layer between the first and second substrates, the backlight unit including a plurality of lamps sequentially turned on/off, each of the plurality of lamps being periodically turned on for a predetermined period, the method comprising:

applying a first lamp current to one of the plurality of lamps for a first time period within the predetermined period so that the one of the plurality of lamps emits light with a first brightness; and

applying a second lamp current to the one of the plurality of lamps for a second time period within the predetermined period so that the one of the plurality of lamps emits light with a second brightness,

wherein the first time period includes a first time segment and a second time segment, and the first time segment and the second time segment are separated by the second time period.

8. The method according to claim 7, wherein the second lamp current is greater than the first lamp current.

9. The method according to claim 8, wherein the first lamp current is less than about 6 milli-amperes (mA) and the second lamp current is more than about 6 milli-amperes (mA).

10. The method according to claim 7, wherein the second brightness is higher than the first brightness.

11. The method according to claim 7, wherein the second time period is shorter than the first time period.

12. The method according to claim 11, wherein the plurality of lamps include a first lamp and a second lamp adjacent to the first lamp, the predetermined period of the first lamp overlapping with the predetermined period of the second lamp.

13. The method according to claim 7, wherein the step of applying the second current includes applying the second lamp current when response of the liquid crystal layer is completed.

14. The method according to claim 7, wherein the step of applying the second current includes applying the second lamp current right after response of the liquid crystal layer is completed.

15. A method of driving a backlight unit of a liquid crystal display device, the backlight unit having a plurality of lamps, each of the plurality of lamps being periodically turned on for a predetermined period, the method comprising:

applying a current of a first level to one of the plurality of lamps; and

increasing the current applied to the one of the plurality of lamps from the first level to a second level for a time period within the predetermined period upon completion of a response of a liquid crystal layer of the liquid crystal display device corresponding to the one of the plurality of lamps.

16. The method according to claim 15, further comprising reducing the current to the first level after the time period ends and until the predetermined period ends.

17. The method according to claim 15, wherein a brightness of the one of the plurality of lamps when the current is in the second level is higher than the brightness of the one of the plurality of lamps when the current is in the first level.

18. The method according to claim 15, wherein the plurality of lamps include a first lamp and a second lamp adjacent to the first lamp, the predetermined period of the first lamp overlapping with the predetermined period of the second lamp.