Backlight unit and display device having backlight unit

• US 10,030,845 B2
• Filed: 11/02/2015
• Issued: 07/24/2018
• Est. Priority Date: 10/31/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Oh, Sewon, Kim, Eunseok
• Primary Examiner(s): Kryukova, Erin
• Application Number:
  US14/929,828
• Publication Number:
  US 20160138779A1
• Time in Patent Office: 995 Days
• Field of Search: 362 971- 974
• CPC Class Codes: F21V 7/0066 specially adapted to cooperate with point like light sources; specially adapted to cooperate with light sources the shape of which is unspecified F21V7/16 - F21V7/30 take precedence
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity

Abstract

A backlight unit is discussed, which includes a frame including a bottom and a sidewall extending from the bottom; at least one substrate located on the frame, and a plurality of light sources mount on the at least one substrate; and a reflecting sheet located on the at least one substrate, wherein the reflecting sheet includes: a first sheet part located on the bottom, the first sheet part including a plurality of holes corresponding to the plurality of the light sources; a second sheet part extended from the first sheet; and a third sheet part extended from the second sheet part and located on the sidewall; wherein the second sheet part comprises a plurality of dot areas positioned sequentially in a direction from the first sheet part to the third sheet part and the plurality of dot areas include a first dot area and a second dot area, the first dot area including a plurality of dots having the same size and the second dot area including a plurality of dots having the same size, and wherein a size of the plurality of dots in the first dot area is different from a size of the plurality of dots in the second dot area.

Claims

1. A backlight unit comprising:

a frame including a bottom and a sidewall extending from the bottom;

at least one substrate located on the frame, and a plurality of light sources mounted on the at least one substrate; and

a reflecting sheet located on the at least one substrate,

wherein the reflecting sheet comprises;

a first sheet part located on the bottom, the first sheet part including a plurality of holes corresponding to the plurality of the light sources; and

a second sheet part extending from the first sheet part, the second sheet part including a horizontal dot area located along a long side of the reflecting sheet and a vertical dot area located along a short side of the reflecting sheet, and at least one of the horizontal dot area and the vertical dot area comprising first and second areas,

wherein the first areas are respectively located corresponding to outermost holes among the plurality of holes disposed along at least one of the long side or short side of the reflecting sheet,

wherein the second areas are located between the first areas,

wherein the first areas and the second areas each have a plurality of subdot areas,

wherein each of the subdot areas includes a plurality of dots with a same size,

wherein the first and second areas each include a first subdot area of the plurality of subdot areas located nearest to an imaginary line connecting the outermost holes,

wherein the first subdot area of the first areas is closer to the imaginary line than the first subdot area of the second areas, and

wherein the first subdot area of the first areas is aligned with a perpendicular line with respect to the imaginary line.

2. The backlight unit of claim 1, further comprising at least one of a diffusion plate and an optical sheet located on the reflecting sheet.

3. The backlight unit of claim 1, further comprising a plurality of lenses located on the plurality of light sources.

4. The backlight unit of claim 1, further comprising a plurality of pins fixing the reflecting sheet to the frame.

5. The backlight unit of claim 1, wherein, in a corner of the reflecting sheet, a shape of the horizontal dot area and a shape of the vertical dot area are asymmetric.

6. The backlight unit of claim 1, further comprising a cut line on a corner of the reflecting sheet,

wherein a distance between a specific point on the cut line and a dot nearest to the cut line in a direction parallel to a first side of the reflecting sheet is different from a distance between the specific point and a dot nearest to the cut line in a direction parallel to a second side of the reflecting sheet.

7. The backlight unit of claim 1, wherein a distance between the horizontal dot area and a horizontal line connecting the outermost holes along the long side of the reflecting sheet is greater than a distance between the vertical dot area and a vertical line connecting the outermost holes along the short side of the reflecting sheet.

8. The backlight unit of claim 1, wherein the reflecting sheet comprises a third sheet part extending from the second sheet part and positioned on the sidewall, and wherein a distance between a nearest boundary to the third sheet part in the horizontal dot area and a horizontal line connecting the outermost holes along the long side of the reflecting sheet is greater than a distance between a nearest boundary to the third sheet part in the vertical dot area and a vertical line connecting the outermost holes along the short side of the reflecting sheet.

9. The backlight unit of claim 1, wherein a size of dots included in one of the first areas is different from a size of dots included in another of the first areas.

10. The backlight unit of claim 1, wherein a size of dots included in one of the second areas is different from a size of dots included in another of the second areas.

11. The backlight unit of claim 1, wherein a size of dots included in one of the first areas is smaller than a size of dots included in another of the first areas, the one of the first areas being close to the imaginary line than the another of the first areas.

12. The backlight unit of claim 1, wherein a size of dots included in one of the second areas is smaller than a size of dots included in another of the second areas, the one of the second areas being closer to the imaginary line than the another of the second areas.

13. The backlight unit of claim 1, wherein a distance between horizontal holes located along the horizontal dot area is smaller than a distance between vertical holes located along the vertical dot area.

14. The backlight unit of claim 1, wherein the second sheet part is inclined from the first sheet part.

15. The backlight unit of claim 1, wherein the reflecting sheet comprises a third sheet part extending from the second sheet part and positioned on the sidewall, and

wherein the third sheet part is inclined from the second sheet part.

16. The backlight unit of claim 1, wherein the first dot area of the first areas protrudes toward a corresponding light source.

17. A display device comprising:

a display panel;

a backlight unit positioned on a rear of the display panel; and

a back cover positioned on a rear of the backlight unit,

wherein the backlight unit comprises;

a frame including a bottom and a sidewall extending from the bottom;

at least one substrate located on the frame, and a plurality of light sources mounted on the at least one substrate; and

a reflecting sheet located on the at least one substrate,

wherein the reflecting sheet comprises;

a first sheet part located on the bottom, the first sheet part including a plurality of holes corresponding to the plurality of the light sources; and

a second sheet part extending from the first sheet part, the second sheet part including a horizontal dot area located along a long side of the reflecting sheet and a vertical dot area located along a short side of the reflecting sheet, and at least one of the horizontal dot area and the vertical dot area comprising first and second areas,

wherein the first areas are respectively located corresponding to outermost holes among the plurality of holes disposed along at least one of the long side or short side of the reflecting sheet,

wherein the second areas are located between the first areas,

wherein the first areas and the second areas each have a plurality of subdot areas,

wherein each of the subdot areas includes a plurality of dots with a same size,

wherein the first and second areas each include a first subdot area of the plurality of subdot areas located nearest to an imaginary line connecting the outermost holes,

wherein the first subdot area of the first areas is closer to the line than the first subdot area of the second areas, and

wherein the first subdot area of the first areas is aligned with a perpendicular line with respect to the imaginary line.

18. The display device of claim 17, further comprising at least one of a diffusion plate and an optical sheet located on the reflecting sheet.

19. The display device of claim 17, further comprising a plurality of lenses located on the plurality of light sources.

20. The display device of claim 17, further comprising a plurality of pins fixing the reflecting sheet to the frame.

21. The display device of claim 17, wherein, in a corner of the reflecting sheet, a shape of the horizontal dot area and a shape of vertical dot area are asymmetric.

22. The display device of claim 17, further comprising a cut line on a corner of the reflecting sheet,

wherein a distance between a specific point on the cut line and a dot nearest to the cut line in a direction parallel to a first side of the reflecting sheet is different from a distance between the specific point and a dot nearest to the cut line in a direction parallel to a second side of the reflecting sheet.

23. The display device of claim 17, wherein a distance between the horizontal dot area and a horizontal line connecting the outermost holes along the long side of the reflecting sheet is greater than a distance between the vertical dot area and a vertical line connecting the outermost holes along the short side of the reflecting sheet.

24. The display device of claim 17, wherein the reflecting sheet comprises a third sheet part extending from the second sheet part and positioned on the sidewall, and

wherein a distance between a nearest boundary to the third sheet part in the horizontal dot area and a horizontal line connecting the outermost holes along the long side of the reflecting sheet is greater than a distance between a nearest boundary to the third sheet part in the vertical dot area and a vertical line connecting the outermost holes along the short side of the reflecting sheet.

25. The display device of claim 17, wherein a size of dots included in one of the first areas is different from a size of dots included in another of the first areas.

26. The display device of claim 17, wherein a size of dots included in one of the second areas is different from a size of dots included in another of the second areas.

27. The display device of claim 17, wherein a size of dots included in one of the first areas is smaller than a size of dots included in another of the first areas, the one of the first areas being close to the imaginary line than the another of the first areas.

28. The display device of claim 17, wherein a size of dots included in one of the second areas is smaller than a size of dots included in another of the second areas, the one of the second areas being closer to the imaginary line than the another of the second areas.

29. The display device of claim 17, wherein a distance between horizontal holes located along the horizontal dot area is smaller than a distance between vertical holes located along the vertical dot area.

30. The display device of claim 17, wherein the second sheet part is inclined from the first sheet part.

31. The display device of claim 17, wherein the reflecting sheet comprises a third sheet part extending from the second sheet part and positioned on the sidewall, and wherein the third sheet part is inclined from the second sheet part.

32. The display device of claim 17, wherein the first dot area of the first areas protrudes toward a corresponding light source.