Backlight module and display device

Patent metadata

Field	Value
Publication number	US-10908454-B2
Application number	US-201715628490-A
Country	US
Kind code	B2
Filing date	Jun 20, 2017
Priority date	Dec 29, 2016
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

A backlight module and a display device include a light guide plate and a point light source. The light guide plate includes a first part and a second part. The first part includes a first light incidence surface and a first light-emitting surface intersecting with the first light incidence surface. The second part includes a second light incidence surface and a second light-emitting surface intersecting with the second light incidence surface. The first light incidence surface intersects with the second light-emitting surface, the first light-emitting surface and the second light incidence surface are arranged oppositely, and both the first light-emitting surface and the second light-emitting surface include grating structures.

First claim

What is claimed is:

1. A backlight module, comprising:
a light guide plate and a point light source;
wherein the light guide plate comprises:
a first part comprising a first light incidence surface and a first light-emitting surface intersecting with the first light incidence surface; and
a second part comprising a second light incidence surface and a second light-emitting surface intersecting with the second light incidence surface;
wherein a plane where the first light incidence surface is located intersects with a plane where the second light-emitting surface is located, wherein the first light-emitting surface and the second light incidence surface are arranged opposite to each other, wherein both the first light-emitting surface and the second light-emitting surface comprise grating structures;
wherein the point light source is arranged at the first light incidence surface of the light guide plate, wherein a light ray emitted by the point light source enters at a first preset angle into the first part, undergoes multiple total reflections in the first part, exits the first light-emitting surface, enters the second light incidence surface, undergoes multiple total reflections in the second part and finally emits from the second light-emitting surface;
wherein an included angle between the first light-emitting surface and the second light-emitting surface is less than 90 degrees and greater than 0 degree;
wherein the first part further comprises a side surface intersecting with the first light incidence surface and the first light-emitting surface, wherein the side surface and the second light-emitting surface are in the same plane;
wherein the second part emits a light ray along a direction perpendicular to the second light-emitting surface; and
wherein the light ray emitted from the second light-emitting surface has a same polarization state as the light ray incident at the first light incidence surface of the first part.

2. The backlight module according to claim 1 , wherein the first light-emitting surface seamlessly fits to the second light incidence surface.

3. The backlight module according to claim 1 , wherein the grating structures of the first light-emitting surface and the second light-emitting surface are fabricated by slotting, imprinting, holographic or bonding periodic metal patch processes.

4. The backlight module according to claim 1 , wherein there is a second preset angle between the first light-emitting surface and the second light-emitting surface.

5. The backlight module according to claim 1 , wherein all surfaces in the first part are reflecting surfaces except for the first light incidence surface and the first light-emitting surface.

6. The backlight module according to claim 5 , wherein the first part is a column having a parallelogram cross section, wherein the first light incidence surface is a bottom surface of the first part, and wherein the first light-emitting surface is a side surface of the first part.

7. The backlight module according to claim 1 , wherein all surfaces in the second part are reflecting surfaces except for the second light incidence surface and the second light-emitting surface.

8. The backlight module according to claim 7 , wherein the second part is a column having a cross section of a right-angled trapezoid, and wherein the second light incidence surface is one side surface of the second part, and the second light-emitting surface is another side surface of the second part.

9. The backlight module according to claim 1 , wherein the light guide plate further comprises a third part, positioned at a side of the first part opposite to the second part, and wherein the first part, the second part and the third part are pieced together to form a cuboid structure.

10. The backlight module according to claim 9 , wherein a refractive index of the first part is greater than that of the third part.

11. The backlight module according to claim 10 , wherein a refractive index of the second part is equal to that of the third part.

12. The backlight module according to claim 1 , wherein the point light source comprises an optical fiber laser light source, a laser diode, or a light-emitting diode having high degree of coherence.

13. A display device, comprising a backlight module, wherein the backlight module comprises a light guide plate and a point light source,
wherein the light guide plate comprises:
a first part comprising a first light incidence surface and a first light-emitting surface intersecting with the first light incidence surface; and
a second part comprising a second light incidence surface and a second light-emitting surface intersecting with the second light incidence surface;
wherein a plane where the first light incidence surface is located intersects with a plane where the second light-emitting surface is located, wherein the first light-emitting surface and the second light incidence surface are arranged opposite to each other, wherein both the first light-emitting surface and the second light-emitting surface comprise grating structures;
wherein the point light source is arranged at the first light incidence surface of the light guide plate, wherein a light ray emitted by the point light source enters at a first preset angle into the first part, undergoes multiple total reflections in the first part, exits the first light-emitting surface, enters the second light incidence surface, undergoes multiple total reflections in the second part and finally emits from the second light-emitting surface;
wherein an included angle between the first light-emitting surface and the second light-emitting surface is less than 90 degrees and greater than 0 degree;
wherein the first part further comprises a side surface intersecting with the first light incidence surface and the first light-emitting surface, wherein the side surface and the second light-emitting surface are in the same plane;
wherein the second part emits a light ray along a direction perpendicular to the second light-emitting surface; and
wherein the light ray emitted from the second light-emitting surface has a same polarization state as the light ray incident at the first light incidence surface of the first part.

14. The display device according to claim 13 , wherein the first light-emitting surface seamlessly fits to the second light incidence surface.

15. The display device according to claim 13 , wherein a refractive index of the first part is greater than that of the second part.

16. The display device according to claim 13 , wherein the first light-emitting surface and the second light-emitting surface comprise grating structures made from slotting, imprinting, holographic or bonding periodic metal patch processes.

17. The display device according to claim 13 , wherein there is a second preset angle between the first light-emitting surface and the second light-emitting surface.

18. The display device according to claim 13 , wherein all surfaces in the first part are reflecting surfaces except for the first light incidence surface and the first light-emitting surface.

19. The display device according to claim 18 , wherein the first part is a column having a cross section of a parallelogram, the first light incidence surface is a bottom surface of the first part, and the first light-emitting surface is a side surface of the first part.

Assignees

• Shanghai Tianma Micro Elect Co
• Tianma Micro Electronics Co Ltd

Inventors

• Liu Yaoyang
• Niu Lei
• Li Jialing
• Ding Yuan
• Ma Jun

Classifications

• G02B6/002 Primary

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

• G02F1/133602 Primary

  Direct backlight · CPC title

• G02B6/0073

  Light emitting diode [LED] · CPC title

• G03H1/22

  Processes or apparatus for obtaining an optical image from holograms (G03H1/26 - G03H1/34 take precedence) · 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