Backlight unit

• US 20070058390A1
• Filed: 09/07/2006
• Published: 03/15/2007
• Est. Priority Date: 09/15/2005
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Original Assignee: NEC LCD Technologies Limited (Tianma Microelectronics Company Limited)
• Inventors: Sugawara, Hideaki, Ishida, Hiroshi
• Granted Patent: US 7,641,373 B2
• Time in Patent Office: Days
• US Class Current: 362/560
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity

Abstract

Disclosed is a backlight unit which illuminates a display panel from a rear surface thereof, including at least: tubular lamps arranged in parallel to the panel; and a reflecting member which reflects light from the lamps toward the panel, wherein the reflecting member is divided into a first region opposed to an area near an electrode provided in an end portion of the lamp and a second region nearer to a middle area than the first region, the first region having a higher reflectance than the second region. In another backlight unit, a reflecting member is divided, with respect to the arrangement direction of the lamps, into an end lamp near region which is opposed to a lamp arranged in end portion and a middle region which is nearer to a middle area than the end lamp region, the end lamp region having a higher reflectance than the middle region.

Claims

1. A backlight unit which illuminates a display panel from a rear surface thereof, comprising at least:

tubular lamps arranged in parallel to the display, panel; and

a reflecting member which reflects light from the lamps, toward the display panel,

wherein the reflecting member is divided into a first region opposed to an area near an electrode provided in an end portion of the lamp and a second region nearer to a middle area than the first region,

the first region having a higher reflectance than the second region.

2. The backlight unit according to claim 1,

wherein the reflecting member includes:

a first reflector which is disposed in the first region and the second region; and

a second reflector disposed in the first region.

3. The backlight unit according to claim 1,

wherein the reflecting member includes:

a first reflector disposed in the second region; and

a second reflector which is disposed in the first region and has a higher reflectance than the first reflector.

4. The backlight unit according to claim 1,

wherein the reflecting member includes:

a reflector disposed in the first region and the second region; and

an absorber which is disposed in the second region and has a prescribed absorptivity.

5. The backlight unit according to claim 1,

wherein the reflecting member includes:

a reflector disposed in the first region and the second region; and

a reflecting film having a prescribed reflectance which is formed in the first region of the reflector.

6. The backlight unit according to claim 1,

wherein the reflecting member includes:

a reflector disposed in the first region and the second region; and

an absorbing film having a prescribed absorptivity which is formed in the second region of the reflector.

7. The backlight unit according to claim 1,

wherein each of the lamps is a U-shaped lamp.

8. The backlight unit according to claim 1,

wherein the reflecting member further comprises a third region between the first region and the second region,

the third region having a reflectance which is lower than the reflectance of the first region and higher than the reflectance of the second region.

9. The backlight unit according to claim 1,

wherein the first region further includes a region opposed to an area near a lamp arranged in an end portion with respect to the arrangement direction of the lamps.

10. The backlight unit according to claim 9,

wherein the first region has a shape which surrounds the second region.

11. The backlight unit according to claim 9,

wherein the reflecting member includes:

a first reflector disposed in the first region and the second region; and

a second reflector disposed in the first region.

12. The backlight unit according to claim 9,

wherein the reflecting member includes:

a first reflector disposed in the second region; and

a second reflector which is disposed in the first region and has a higher reflectance than the first reflector.

13. The backlight unit according to claim 9,

wherein the reflecting member includes:

a reflector disposed in the first region and the second region; and

an absorber which is disposed in the second region and has a prescribed absorptivity.

14. The backlight unit according to claim 9,

wherein the reflecting member includes:

a reflector disposed in the first region and the second region; and

a reflecting film having a prescribed reflectance which is formed in the first region of the reflector.

15. The backlight unit according to claim 9,

wherein the reflecting member includes:

a reflector disposed in the first region and the second region; and

an absorbing film having a prescribed absorptivity which is formed in the second region of the reflector.

16. The backlight unit according to claim 9,

wherein each of the lamps is a U-shaped lamp.

17. The backlight unit according to claim 16,

wherein the first region further includes a region opposed to an area near a bent portion of the U-shaped lamp.

18. The backlight unit according to claim 1,

wherein the second region is further divided, with respect to the arrangement direction of the lamps, into an end lamp near region which is opposed to an area near a lamp arranged in an end portion and a middle region which is nearer to a middle area than the end lamp near region,

the end lamp near region having a higher reflectance than the middle region.

19. A backlight unit which illuminates a display panel from a rear surface thereof, comprising at least:

tubular lamps arranged in parallel to the display panel; and

a reflecting member which reflects light from the lamps toward the display panel,

wherein the reflecting member is divided, with respect to the arrangement direction of the lamps, into at least an end lamp near region which is opposed to an area near a lamp arranged in an end portion and a middle region which is nearer. to a middle area than the end lamp near region,

the end lamp near region having a higher reflectance than the middle region.