Lighting apparatus having a uniform luminance profile

• US 20060083025A1
• Filed: 09/30/2005
• Published: 04/20/2006
• Est. Priority Date: 10/15/2004
• Status: Active Grant

• Current Assignee: Beihai HKC Optoelectronics Technology Company Limited
• Original Assignee: NEC LCD Technologies Limited (Tianma Microelectronics Company Limited)
• Inventors: Ono, Shin-ichirou
• Granted Patent: US 7,354,173 B2
• Time in Patent Office: Days
• US Class Current: 362/613
• 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

A direct-emission backlight unit for use in an LCD device includes a plurality of elongate lamps at the rear of a light diffusion plate and a plurality of reflecting members arranged in a matrix on a rear reflecting plate. The reflecting members are disposed in the gap between adjacent lamps, and reflect light emitted by the lamps toward the diffusion plate for achieving a uniform luminance profile of the emission surface of the backlight unit.

Claims

1. A lighting apparatus comprising a light diffusion plate, a plurality of luminescent members extending parallel to one another in an operative relationship with said light diffusion plate, and a reflecting member having at least one reflecting surface, at least a portion of said reflecting surface being disposed between adjacent luminescent members and extending in a direction crossing an extending direction of said luminescent members.

2. The lighting apparatus according to claim 1, wherein said at least one reflecting surface include a pair of reflecting surfaces directed to opposite directions.

3. The lighting apparatus according to claim 2, wherein said reflecting member is formed by folding a stripe sheet having a first surface having a specific reflectance and a second surface having thereon an adhesive layer so that said second surface is sandwiched between portions of said first surface.

4. The lighting apparatus according to claim 3, wherein said reflecting member has a thickness of 1 mm or less.

5. The lighting apparatus according to claim 1, further comprising a rear reflection plate disposed opposite to said light diffusion plate to sandwich therebetween said luminescent members and said reflecting member, wherein said reflecting member is fixed onto said rear reflection plate.

6. The lighting apparatus according to claim 2, wherein said reflecting surface has a symmetry with respect to a plane passing through a central line of a gap between said adjacent lamps, and has a depression having a largest depth at said central line.

7. The lighting apparatus according to claim 6, wherein said reflecting surface has two planes crossing each other at said central line.

8. The lighting apparatus according to claim 6, wherein said reflecting surface is a curved surface.

9. The lighting apparatus according to claim 2, wherein said reflecting member is of an isosceles triangle as viewed from side edges thereof.

10. The lighting apparatus according to claim 2, wherein said reflecting surfaces extend parallel to each other in a central portion thereof, and cross each other at an acute angle in vicinities of side edges of said reflecting member.

11. The lighting apparatus according to claim 10, wherein said reflecting member has a thickness larger at a base portion thereof than at a top portion thereof in said vicinities of said side edges.

12. The lighting apparatus according to claim 1, wherein said reflecting surface has a light scattering property.

13. The lighting apparatus according to claim 1, wherein a plurality of said reflecting member are disposed alternately with said luminescent members.

14. The lighting apparatus according to claim 13, wherein a plurality of said reflecting member are arranged in a columnar direction parallel to said extending direction of said luminescent members.

15. The lighting apparatus according to claim 14, wherein adjacent reflecting members in adjacent columns are deviated from each other in said columnar direction.

16. The lighting apparatus according to claim 1, wherein said reflecting member crosses said luminescent member in a direction normal to said extending direction of said luminescent members.

17. The lighting apparatus according to claim 1, wherein said reflecting surface has a reflectance of 97% or higher.

18. The lighting apparatus according to claim 1, wherein a single said light diffusion plate is disposed in front of said luminescent members and said reflecting member.

19. The lighting apparatus according to claim 1, wherein a pair of said light diffusion plate are disposed to sandwich therebetween said luminescent members and said reflecting member.

20. A liquid crystal display (LCD) device comprising a liquid crystal (LC) panel and the lighting apparatus according to claim 1 as a backlight unit for said LC panel.

21. A lighting apparatus comprising a light diffusion plate, a plurality of luminescent members aligned in an extending direction of said luminescent members in an operative relationship with said light diffusion plate, and a reflecting member having at least one reflecting surface in a vicinity of adjacent ends of two of said luminescent members.

22. A liquid crystal display (LCD) device comprising a liquid crystal (LC) panel and the lighting apparatus according to claim 21 as a backlight unit for said LC panel.

23. A lighting apparatus comprising a light diffusion plate, a plurality of elongate lamps extending parallel to one another in an operative relationship with said light diffusion plate, and a reflecting member having at least one reflecting surface and disposed between adjacent two of said lamps apart therefrom, said reflecting surface being substantially normal to an extending direction of said elongate lamps.