BACKLIGHT MODULE AND DOUBLE-SIDED LIQUID CRYSTAL DISPLAY DEVICE

• US 20190064598A1
• Filed: 05/21/2018
• Published: 02/28/2019
• Est. Priority Date: 08/28/2017
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: DU, Zhihong, LI, Wenbo
• Granted Patent: US 10,642,101 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0063 for extracting light out both the major surfaces of the light guide
• CPC Class Codes: G02F 1/133342 for double-sided displays
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

The present disclosure provides a backlight module and a double-sided liquid crystal display device. The light utilization efficiency of the backlight module is improved. The backlight module includes a light emitting component, the light emitting component includes a first light exit surface and a second light exit surface disposed opposite to each other. A first liquid crystal brightness enhancement film and a first quarter-wave plate are sequentially disposed along a light emitting direction of the first light exit surface. A second liquid crystal brightness enhancement film and a second quarter-wave plate are sequentially disposed along a light emitting direction of the second light exit surface. A rotation structure of the first liquid crystal brightness enhancement film is opposite to a rotation structure of the second liquid crystal brightness enhancement film.

Claims

1. A backlight module, comprising:

a light emitting component comprising a first light exit surface and a second light exit surface disposed opposite to each other;

a first liquid crystal brightness enhancement film and a first quarter-wave plate sequentially disposed along a light emitting direction of the first light exit surface;

a second liquid crystal brightness enhancement film and a second quarter-wave plate sequentially disposed along a light emitting direction of the second light exit surface;

wherein a rotation structure of the first liquid crystal brightness enhancement film is opposite to a rotation structure of the second liquid crystal brightness enhancement film.

2. The backlight module according to claim 1, wherein each liquid crystal brightness enhancement film comprises two diaphragms disposed opposite to each other and a cholesteric liquid crystal layer sandwiched between the two diaphragms.

3. The backlight module according to claim 1, wherein the light emitting component comprises:

a light guide plate and a light source;

the light guide plate comprises two light exit surfaces serving as the first light exit surface and the second light exit surface, respectively, and a lateral surface connecting the two light exit surfaces;

the lateral surface comprises at least a light incident surface;

a light emitting surface of the light source faces the light incident surface of the light guide plate.

4. The backlight module according to claim 3, wherein a plurality of grooves with a longitudinal section of triangular shape are disposed on each light exit surface, and the plurality of grooves on the first light exit surface are interlaced with the plurality of grooves on the second light exit surface;

the plurality of grooves on the first light exit surface are arranged to redirect light emitted by the light source to the second light exit surface, and the plurality of grooves on the second light exit surface are arranged to redirect light emitted by the light source to the first light exit surface.

5. The backlight module according to claim 4, wherein an angle between a reflective surface of the groove and the light exit surface provided with the groove increases in a direction away from the light source that emits light to the reflective surface of the groove.

6. The backlight module according to claim 5, wherein the angle a between the reflective surface of the groove and the light exit surface provided with the groove satisfies:

α

=(90−

A)/2

wherein A represents an angle between light incident on the reflective surface and a plane where the light exit surface is located.

7. The backlight module according to claim 1, wherein the light emitting component comprises:

a first diffusion plate and a second diffusion plate disposed opposite to each other, and a light source located between the first diffusion plate and the second diffusion plate;

a light exit surface of the first diffusion plate serves as the first light exit surface of the light emitting component, and a light exit surface of the second diffusion plate serves as the second light exit surface of the light emitting component.

8. The backlight module according to claim 7, wherein the light source comprises a transparent circuit board;

the transparent circuit board comprises a first surface and a second surface disposed opposite to each other;

the first surface and the second surface are provided with a plurality of light emitting devices respectively.

9. The backlight module according to claim 8, wherein the light emitting devices on the first surface are disposed symmetrical with the light emitting devices on the second surface.

10. The backlight module according to claim 7, wherein the light source comprises a plurality of transparent support bars arranged at intervals and in parallel;

each transparent support bar comprises a first surface and a second surface disposed opposite to each other;

the first surface and the second surface are provided with a plurality of light emitting devices respectively.

11. A double-sided liquid crystal display device, comprising:

a first liquid crystal display panel and a second liquid crystal display panel arranged opposite to each other, and the backlight module according to claim 1;

wherein the backlight module is arranged between the first liquid crystal display panel and the second liquid crystal display panel.

12. The double-sided liquid crystal display device according to claim 11, wherein the first liquid crystal display panel is disposed on a light exit side of the first quarter-wave plate, and a first polarizer is provided on a light incident side of the first liquid crystal display panel;

a polarization direction of light emitted from the first quarter-wave plate is parallel to a direction of a transmission axis of the first polarizer.

13. The double-sided liquid crystal display device according to claim 12, wherein the second liquid crystal display panel is disposed on a light exit side of the second quarter-wave plate, and a second polarizer is provided on a light incident side of the second liquid crystal display panel;

a polarization direction of light emitted from the second quarter-wave plate is parallel to a direction of a transmission axis of the second polarizer;

the direction of the transmission axis of the first polarizer is perpendicular to a direction of a transmission axis of the second polarizer.

14. The double-sided liquid crystal display device according to claim 11, wherein each liquid crystal brightness enhancement film comprises two diaphragms disposed opposite to each other and a cholesteric liquid crystal layer sandwiched between the two diaphragms.

15. The double-sided liquid crystal display device according to claim 11, wherein the light emitting component comprises:

a light guide plate and a light source;

the light guide plate comprises two light exit surfaces serving as the first light exit surface and the second light exit surface, respectively, and a lateral surface connecting the two light exit surfaces;

the lateral surface comprises at least a light incident surface;

a light emitting surface of the light source faces the light incident surface of the light guide plate.

16. The double-sided liquid crystal display device according to claim 15, wherein a plurality of grooves with a longitudinal section of triangular shape are disposed on each light exit surface, and the plurality of grooves on the first light exit surface are interlaced with the plurality of grooves on the second light exit surface;

the plurality of grooves on the first light exit surface are arranged to redirect light emitted by the light source to the second light exit surface, and the plurality of grooves on the second light exit surface are arranged to redirect light emitted by the light source to the first light exit surface.

17. The double-sided liquid crystal display device according to claim 16, wherein an angle between a reflective surface of the groove and the light exit surface provided with the groove increases in a direction away from the light source that emits light to the reflective surface of the groove.

18. The double-sided liquid crystal display device according to claim 17, wherein the angle α

between the reflective surface of the groove and the light exit surface provided with the groove satisfies;

α

=(90−

A)/2

wherein A represents an angle between light incident on the reflective surface and a plane where the light exit surface is located.

19. The double-sided liquid crystal display device according to claim 11, wherein the light emitting component comprises:

a first diffusion plate and a second diffusion plate disposed opposite to each other, and a light source located between the first diffusion plate and the second diffusion plate;

a light exit surface of the first diffusion plate serves as the first light exit surface of the light emitting component, and a light exit surface of the second diffusion plate serves as the second light exit surface of the light emitting component.

20. The double-sided liquid crystal display device according to claim 19, wherein the light source comprises a transparent circuit board;

the transparent circuit board comprises a first surface and a second surface disposed opposite to each other;

the first surface and the second surface are provided with a plurality of light emitting devices respectively.