Backlight unit, display apparatus comprising the same and control method thereof

• US 20070030697A1
• Filed: 07/25/2006
• Published: 02/08/2007
• Est. Priority Date: 08/05/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Young-kook
• Granted Patent: US 7,441,935 B2
• Time in Patent Office: Days
• US Class Current: 362/618
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• 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 display apparatus including a liquid crystal display (LCD) panel, a light source unit including a plurality of point light sources to provide light to the LCD panel and divided into a plurality of light source areas, a plurality of light source driving parts to supply electric power to the plurality of light source areas, a brightness sensor to sense a brightness of the light source unit, and a light source controller to control the light source driving part based on the brightness sensed by the brightness sensor so that the light source unit provides light of uniform brightness.

Claims

1. A display apparatus, comprising:

a liquid crystal display panel;

a light source unit comprising a plurality of point light sources to provide light to the liquid crystal display panel and divided into a plurality of light source areas;

a plurality of light source driving parts to supply electric power to corresponding ones of the plurality of light source areas;

a brightness sensor to sense a brightness of the light source unit; and

a light source controller to control the plurality of light source driving parts based on the brightness sensed by the brightness sensor so that the light source unit provides light of uniform brightness.

2. The display apparatus according to claim 1, wherein the brightness sensor senses an actual brightness of each of the plurality of light source areas.

3. The display apparatus according to claim 2, further comprising:

a brightness calculator to calculate an average brightness using each actual brightness of the plurality of light source areas sensed by the brightness sensor, and to calculate a difference between the average brightness and each actual brightness of the light source areas.

4. The display apparatus according to claim 3, wherein the light source controller controls the light source driving part to supply additional electric power to one or more of the plurality of light source areas when the difference between the average brightness and an actual brightness of the one or more of the plurality of the light source areas is out of a predetermined permissible range.

5. The display apparatus according to claim 1, wherein the plurality of point light sources emits a red color, a green color, and a blue color, respectively.

6. The display apparatus according to claim 1, wherein the plurality of light source driving parts supply electric power by emitting colors of the point light source.

7. A backlight unit, comprising:

a light source unit comprising a plurality of point light sources and divided into a plurality of light source areas;

a plurality of light source driving parts to supply electric power to corresponding ones of the plurality of light source areas;

a brightness sensor to sense a brightness of the light source unit; and

a light source controller to control the light source driving part based on the brightness sensed by the brightness sensor so that the light source unit provides light of uniform brightness.

8. The backlight unit according to claim 7, wherein the brightness sensor senses an actual brightness of each of the plurality of light source areas.

9. The backlight unit according to claim 8, further comprising:

a brightness calculator to calculate an average brightness using each actual brightness of the plurality of light source areas sensed by the brightness sensor, and to calculate a difference between the average brightness and each actual brightness of the plurality of light source areas.

10. The backlight unit according to claim 9, wherein the light source controller controls the light source driving part to supply additional electric power to one or more of the plurality of light source areas when the difference between the average brightness and an actual brightness of the one or more of the plurality of light source areas is out of a predetermined permissible range.

11. A control method of a display apparatus, comprising:

providing an LCD panel, a light source unit comprising a plurality of point light sources to provide light to the LCD panel and divided into a plurality of light source areas, a plurality of light source driving parts to supply electric power to corresponding ones of the plurality of light source areas, and a brightness sensor to sense a brightness of the light source unit;

sensing an actual brightness of each of the plurality of light source areas; and

supplying light of uniform brightness based on the sensed brightness.

12. The control method according to claim 11, further comprising:

calculating an average brightness using each actual brightness of the plurality of light source areas; and

calculating a difference between the average brightness and each actual brightness of the plurality of light source areas.

13. The control method according to claim 12, wherein the supplying light supplies additional electric power to one or more of the plurality of light source areas when the difference between the average brightness and an actual brightness of the one or more of the plurality of light source areas is out of a predetermined permissible range.

14. A backlighting unit to transmit light to an image display device, comprising:

a light source unit comprising a plurality of light source areas;

a plurality of brightness sensors located on corresponding ones of the plurality of light source areas to determine an actual brightness of each of the plurality of light source areas; and

a power supply control unit to control an amount of power supplied to each of the light source areas independently based on the determined actual brightness.

15. The backlighting unit according to claim 14, wherein each of the plurality of light source areas comprises:

at least one of the plurality of brightness sensors; and

at least one of the plurality of light sources.

16. The backlighting unit according to claim 14, wherein each of the plurality of light source areas comprises:

a single brightness sensor; and

two or more light sources.

17. The backlighting unit according to claim 14, wherein:

each of the plurality of brightness sensors comprises a converting unit to convert light data corresponding to the actual brightness of each of the plurality of light source areas into an electric signal.

18. The backlighting unit according to claim 14, wherein:

each of the plurality of brightness sensors is located in a middle of corresponding ones of the plurality of light source areas.

19. The backlighting unit according to claim 14, wherein the power supply control unit comprises:

a plurality of driving parts to drive corresponding ones of the plurality of light source areas;

a brightness calculator to determine an average brightness of the light source unit and to calculate differences between the average brightness and each actual brightness of the plurality of light source areas; and

a controller to receive brightness data from the brightness calculator corresponding to the differences and to control the plurality of driving parts based on the brightness data.

20. A method of controlling a backlighting unit comprising a light source unit comprising first and second light source areas, first and second pluralities of light sources respectively located on the first and second light source areas, and first and second brightness sensors respectively located on the first and second light source areas to determine an actual brightness of the first and second light source areas, the method comprising:

determining an average brightness of the light source unit;

calculating a difference between the average brightness and the actual brightness of the first light source area; and

controlling a supply of electric power to the first light source area based on first brightness data corresponding to the difference between the average brightness and the actual brightness of the first light source area.

21. The method according to claim 20, further comprising:

increasing an amount of electric power supplied to the first light source area when the difference between the average brightness and the actual brightness of the first light source area is outside of a predetermined range of values; and

maintaining an amount of electric power supplied to the first light source area when the difference between the average brightness and the actual brightness of the first light source area is within a predetermined range of values, inclusive of end values of the range.

22. The method according to claim 20, further comprising:

calculating a difference between the average brightness and the actual brightness of the second light source area; and

controlling a supply of electric power to the second light source area based on second brightness data corresponding to the difference between the average brightness and the actual brightness of the second light source area.