Back light unit and display device

Patent metadata

Field	Value
Publication number	US-11215745-B1
Application number	US-202117220946-A
Country	US
Kind code	B1
Filing date	Apr 2, 2021
Priority date	Sep 8, 2020
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

A back light unit and a display device are proposed. The back light unit includes a light guide plate and multiple light emitting diodes, wherein the multiple light emitting diodes are disposed on a light entrance surface of a side end of the light guide plate, the light entrance surface of the light guide plate is disposed with at least one groove, and the at least one groove is disposed between at least part of adjacent light emitting diodes.

First claim

What is claimed is:

1. A back light unit, comprising: a light guide plate and a plurality of light emitting diodes, wherein
the plurality of light emitting diodes are disposed on a light entrance surface of a side end of the light guide plate, the light entrance surface of the light guide plate is disposed with at least one groove, and the at least one groove is disposed between at least part of adjacent light emitting diodes,
wherein the back light unit further comprises a mold frame, wherein a first bump and an accommodation recess are disposed on a frame of the mold frame corresponding to the light entrance surface, the first bump is disposed within the groove of the light guide plate, and the light emitting diode is disposed within the accommodation recess, and
wherein the frame is further disposed with a second bump, wherein a position of the second bump corresponds to that of a chamfer structure on the light guide plate, and when the light guide plate is disposed within an accommodation cavity of the mold frame, the second bump is matched with the chamfer structure, and an outer surface of the second bump fits a wedge-shaped surface of the chamfer structure.

2. The back light unit of claim 1 , wherein in a direction parallel to a light exit surface of the light guide plate, a cross-sectional shape of the groove comprises any one or more of the following: an arc, a triangle or a trapezoid.

3. The back light unit of claim 2 , wherein when the cross-sectional shape of the groove is the triangle, two sides of the triangle comprise any one or more of the following: a straight line, a polyline, or an arc line.

4. The back light unit of claim 2 , wherein when the cross-sectional shape of the groove is the trapezoid,
two sides of the trapezoid comprise any one or more of the following: a straight line, a polyline, or an arc line; and
an upper bottom of the trapezoid adjacent to a visible area side of the light guide plate comprises any one or more of the following: a straight line, a polyline, or an arc line.

5. The back light unit of claim 2 , wherein the cross-sectional shape of the groove is the arc, a radius of the arc is 3.5 mm to 4.5 mm, and at a junction between the arc and the light entrance surface, an included angle between a tangent of the arc and the light entrance surface is 40 degrees to 60 degrees.

6. The back light unit of claim 5 , wherein the radius of the arc is 4.11 mm.

7. The back light unit of claim 5 , wherein the included angle between the tangent of the arc and the light entrance surface is 45 degrees.

8. The back light unit of claim 2 , wherein the cross-sectional shape of the groove is the triangle or the trapezoid, and an included angle between a side of the triangle or the trapezoid and the light entrance surface is 40 degrees to 60 degrees.

9. The back light unit of claim 1 , wherein along an extending direction of the light entrance surface of the light guide plate, a width of the groove is 5 mm to 6 mm; along an extending direction of the light entrance surface of the light guide plate toward a visible area of the light guide plate, a depth of the groove is 0.5 mm to 1.5 mm, and a distance between a center line of the groove and a center line of a light emitting diode adjacent to the groove is 3 mm to 6 mm.

10. The back light unit of claim 9 , wherein when a cross-sectional shape of the groove is an arc, the width of the groove is 5.49 mm, the depth of the groove is 1.05 mm, and the distance between the center line of the groove and the center line of the light emitting diode adjacent to the groove is 5 mm.

11. The back light unit of claim 1 , wherein a plurality of microstructures are disposed on a groove wall of the at least one groove, wherein the plurality of microstructures comprise micro grooves recessed toward a visual area of the light guide plate and/or micro protrusions protruding away from the visual area of the light guide plate.

12. The back light unit of claim 11 , wherein in a direction parallel to a light exit surface of the light guide plate, cross-sectional shapes of the micro grooves and/or the micro protrusions comprise any one or more of the following: an arc, a triangle, or a trapezoid, a depth of the micro grooves or a height of the micro protrusions is 10 μm to 100 μm, and an arrangement cycle is 50 μm to 400 μm.

13. The back light unit of claim 1 , wherein a chamfer structure is further disposed between the light entrance surface of the light guide plate and a side end face of the light guide plate adjacent to the light entrance surface, wherein a first end of the chamfer structure is connected with the light entrance surface, and a second end of the chamfer structure is connected with the side end face of the light guide plate adjacent to the light entrance surface, a wedge-shaped surface is formed between the light entrance surface and the side end face.

14. The back light unit of claim 13 , wherein in a direction parallel to the light exit surface of the light guide plate, a cross-sectional shape of the wedge-shaped surface comprises any one or more of the following: a straight line, a polyline, and an arc line.

15. The back light unit of claim 13 , wherein the light guide plate is disposed with at least two chamfer structures, wherein at least one chamfer structure is disposed at a first end of the light entrance surface away from the plurality of light emitting diodes, and at least one chamfer structure is disposed at a second end of the light entrance surface away from the plurality of light emitting diodes.

16. The back light unit of claim 1 , further comprising a back plate and an optical film set, wherein,
the back plate comprises a bottom plate and a side wall positioned at an edge of the bottom plate and perpendicular to the bottom plate, the bottom plate is disposed with a reflective film, and the light guide plate is disposed on the reflective film; and
the optical film set is disposed on light guide plate, and the optical film set comprises a diffusion film disposed on the light guide plate, a lower bright enhancement film disposed on the diffusion film and an upper bright enhancement film disposed on the lower bright enhancement film.

17. The back light unit of claim 1 , wherein an outer surface of the first bump facing a visible area of the light guide plate is a polished surface.

18. A display device, comprising a back light unit, wherein the back light unit comprises a light guide plate and a plurality of light emitting diodes, wherein
the plurality of light emitting diodes are disposed on a light entrance surface of a side end of the light guide plate, the light entrance surface of the light guide plate is disposed with at least one groove, and the at least one groove is disposed between at least part of adjacent light emitting diodes,
wherein the back light unit further comprises a mold frame, wherein a first bump and an accommodation recess are disposed on a frame of the mold frame corresponding to the light entrance surface, the first bump is disposed within the groove of the light guide plate, and the light emitting diode is disposed within the accommodation recess, and
wherein the frame is further disposed with a second bump, wherein a position of the second bump corresponds to that of a chamfer structure on the light guide plate, and when the light guide plate is disposed within an accommodation cavity of the mold frame, the second bump is matched with the chamfer structure, and an outer surface of the second bump fits a wedge-shaped surface of the chamfer structure.

Assignees

• Beijing Boe Optoelectronics Tech Co Ltd
• Boe Technology Group Co Ltd

Inventors

• Du Jingjun
• Liang Fei
• Zhao Chaoyue
• Sun Lingyu
• Chen Xiuyun
• Hou Tingxiu
• Zhong Peng
• Zhao Jian
• Xiao Yongkang

Classifications

• G02B6/0091

  of the light source relative to the light guide (G02B6/0021 takes precedence) · CPC title

• G02B6/0068

  Arrangements of plural sources, e.g. multi-colour light sources · CPC title

• G02B6/002 Primary

  by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces · CPC title

• G02B6/0016

  Grooves, prisms, gratings, scattering particles or rough surfaces · CPC title

• G02B6/0038

  Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide · CPC title