Backlight assembly and liquid crystal display device having improved luminance uniformity

Patent metadata

Field	Value
Publication number	US-10268074-B2
Application number	US-201514931809-A
Country	US
Kind code	B2
Filing date	Nov 3, 2015
Priority date	Feb 2, 2015
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

Disclosed herein are a backlight assembly and a liquid crystal display device including the same, which is capable of producing more uniform luminance. The liquid crystal display device includes: a backlight assembly, and a liquid crystal display panel positioned above the backlight assembly. The backlight assembly includes: reflecting sheets having a first surface roughness and a second surface roughness that are different from each other; and light source disposed adjacent to the reflecting sheets.

First claim

What is claimed is:

1. A backlight assembly comprising:
a first reflecting sheet having a first surface roughness;
a second reflecting sheet having a second surface roughness that is different from the first surface roughness and positioned above the first reflecting sheet; and
a light source emitting light,
wherein the second reflecting sheet has a plurality of holes formed therein, and
the plurality of holes of the second reflecting sheet each overlaps the first reflecting sheet at a portion of the first reflecting sheet that does not comprise any part of any hole of the first reflecting sheet, and
wherein, in areas where the holes are formed a first light emitted from the plurality of light sources is reaching to and reflected by the first reflecting sheet with a first path, and in areas where the holes are not formed a second light is reflected by the second reflecting sheet with a second path,
wherein the second reflecting sheet is integrally formed.

2. The backlight assembly of claim 1 , wherein:
the first surface roughness is larger than the second surface roughness.

3. The backlight assembly of claim 2 , wherein:
an arithmetic average roughness of the first reflecting sheet is about 1.0 μm or more.

4. The backlight assembly of claim 2 , wherein:
a maximum height roughness of the first reflecting sheet is about 10 μm or more.

5. The backlight assembly of claim 2 , wherein:
an arithmetic average roughness of the second reflecting sheet is about 0.1 μm or less.

6. The backlight assembly of claim 2 , wherein:
a maximum height roughness of the second reflecting sheet is about 1.5 μm or more.

7. The backlight assembly of claim 1 , wherein:
an areal density of the holes decreases with distance from the light source.

8. The backlight assembly of claim 1 , wherein:
an areal density of the holes increases with distance from the light source.

9. The backlight assembly of claim 1 , wherein:
the holes are arranged in groups around the light source.

10. The backlight assembly of claim 1 , wherein:
the holes have at least one of a circular shape, an oval shape, a triangular shape, a quadrangular shape, and a polygonal shape.

11. The backlight assembly of claim 1 , wherein:
the first surface roughness is smaller than the second surface roughness.

12. The backlight assembly of claim 11 , wherein:
an areal density of the holes decreases with distance from the light source.

13. The backlight assembly of claim 11 , wherein:
an areal density of the holes increases with distance from the light source.

14. The backlight assembly of claim 1 , further comprising:
a lens positioned above and enclosing the light source.

15. The backlight assembly of claim 14 , wherein:
the light source is configured to direct light in a vertical direction at least approximately perpendicular to an upper surface of the reflecting sheets, and the lens is configured to emit the light supplied from the light source through sides thereof.

16. The backlight assembly of claim 14 , wherein:
the lens is configured to emit light supplied from the light source through an upper surface thereof.

17. A liquid crystal display device comprising:
a backlight assembly; and
a liquid crystal display panel positioned above the backlight assembly;
wherein the backlight assembly includes:
a first reflecting sheet having a first surface roughness;
a second reflecting sheet having a second surface roughness that is different from the first surface roughness and positioned above the first reflecting sheet; and
a light source emitting light,
wherein the second reflecting sheet has a plurality of holes formed therein,
the plurality of holes of the second reflecting sheet each overlaps the first reflecting sheet at a portion of the first reflecting sheet that does not comprise any part of any hole of the first reflecting sheet, and
wherein, in areas where the holes are formed a first light emitted from the plurality of light sources is reaching to and reflected by the first reflecting sheet with a first path, and in areas where the holes are not formed a second light is reflected by the second reflecting sheet with a second path
wherein the second reflecting sheet is integrally formed.

18. The liquid crystal display device of claim 17 , wherein:
the first surface roughness is larger than the second surface roughness.

19. The liquid crystal display device of claim 18 , wherein:
an areal density of the holes decreases with distance from the light source.

20. The liquid crystal display device of claim 18 , wherein:
an areal density of the holes increases with distance from the light source.

21. The liquid crystal display device of claim 17 , wherein:
the first surface roughness is smaller than the second surface roughness.

22. The liquid crystal display device of claim 21 , wherein:
an areal density of the holes decreases with distance from the light source.

23. The liquid crystal display device of claim 21 , wherein:
an areal density of the holes increases with distance from the light source.

24. The liquid crystal display device of claim 17 , wherein:
the backlight assembly further includes a lens positioned above and enclosing the light source.

25. The liquid crystal display device of claim 24 , wherein:
the light source is configured to direct light in a vertical direction at least approximately perpendicular to an upper surface of the reflecting sheets, and the lens is configured to emit the light supplied from the light source through sides thereof.

26. The liquid crystal display device of claim 24 , wherein:
the lens is configured to emit light supplied from the light source through an upper surface thereof.

27. The backlight assembly of claim 1 , wherein:
the holes are positioned so that successive holes extend radially outward from the light source.

28. The backlight assembly of claim 17 , wherein:
the holes are positioned so that successive holes extend radially outward from the light source.

29. The backlight assembly of claim 1 , wherein each of the plurality of holes are separate from each other, are circular, have a same size as each other, and do not surround any area of the second reflecting sheet where holes are not formed.

30. The backlight assembly of claim 1 , wherein the light source is disposed on the second reflecting sheet.

Assignees

• Samsung Display Co Ltd

Inventors

• Ha Ju Hwa

Classifications

• G02F1/133606

  including a specially adapted diffusing, scattering or light controlling members · CPC title

• G02F1/133605 Primary

  including specially adapted reflectors · CPC title

• G02B19/0028

  refractive and reflective surfaces, e.g. non-imaging catadioptric systems · CPC title

• G02F1/133603

  with LEDs · CPC title

• G02B5/0221

  the surface having an irregular structure (G02B5/0226 takes precedence) · CPC title