Backlight module using laser emitters as light source

• US 8,979,344 B2
• Filed: 04/29/2013
• Issued: 03/17/2015
• Est. Priority Date: 12/24/2012
• Status: Active Grant

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: Chen, Po-Chou
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): ZIMMERMAN, GLENN D
• Application Number:
  US13/873,142
• Publication Number:
  US 20140177273A1
• Time in Patent Office: 687 Days
• Field of Search: 362/609, 362/633, 362/602, 362/97.1, 362/97.2, 362/97.3, 362/623, 362/624, 349/65
• US Class Current: 362/609
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type

Abstract

A backlight module includes a laser light source and a light guide plate. The light source locates beside a side surface of the light guide plate. The light guide plate comprises a plurality of transflective films arranged along a direction in alignment the laser light source. When the light from the laser light source emits to the transflective films, a part of the light passes through the transflective films and transmits along a same direction, and another part of the light is reflected by the transflective films and emits into a light diffusion plate. The light beams reflected by the transflective films and into the light diffusion plate have the same intensity.

Claims

1. A backlight module, comprising:

a laser light source for generating light; and

a light guide plate, the laser light source being located beside a side surface of the light guide plate, the light guide plate comprising a light diffusion plate and a plurality of transflective films arranged along a direction in alignment with the laser light source, when the light from the laser light source emits to the transflective films, a part of the light passing through the transflective films and transmitting along a same direction, another part of the light being reflected by the transflective films to reach the light diffusion plate, except the one of the transflective films which is located most distant from the laser light source, the most distant transflective film only reflecting the part of the light incident thereon to direct the part of the light incident thereon to totally reach the light diffusion plate;

the light guide plate comprises a frame, the frame comprises a bottom plate, a cover and a side plate connected between the bottom plate and the cover, the transflective films are positioned between the bottom plate and the cover, the side plate defines a light incident hole in a position corresponding to the laser light source, and the cover defines a plurality of light emitting holes directly over the transflective films, respectively.

2. The backlight module of claim 1, wherein a reflectivity R_i, and a transmissivity T_i, of an i-th transflective film can be calculated as following equation:

R_i=1/(N−

i+1);

T_i=(N−

i+1)

wherein N represents a number of the transflective films, the i-th transflective film means that there are (i-1) transflective films located between the i-th transflective film and the laser light source, the i and N are positive integer numbers, and i is less than or equal to N.

3. The backlight module of claim 1, wherein the transflective films are paralleled to each other.

4. The backlight module of claim 3, wherein an included angle between the transflective film and a light emitting direction of the laser light source is about 45 degrees.

5. The backlight module of claim 1, wherein the laser light source comprises laser emitters.

6. The backlight module of claim 5, wherein the laser light source comprises a first laser emitter, a second laser emitter, a third laser emitter and a light combination device, the first laser emitter emits a red light beam, the second laser emitter emits a green light beam, and the third emitter emits a blue light beam, the light beams from the first laser emitter, the second laser emitter and the third laser emitter are mixed in the light combination device to become a white light beam.

7. The backlight module of claim 6, wherein the light combination device is an X-prism.

8. The backlight module of claim 1, wherein the light guide plate further comprises light diffusing elements, and each of the light diffusion elements is located directly above a corresponding one of the transflective films.

9. The backlight module of claim 8, wherein each of the light diffusion elements comprises a light incident surface and a light emitting surface, the part of the light reflected by the corresponding one of the transflective films emits into the light diffusion element through the light incident surface, and emits out of the light diffusion element through the light emitting surface.

10. The backlight module of claim 9, wherein a plurality of diffusing particles are doped in each of the light diffusion elements, and the diffusing particles are located between the light incident surface and the light emitting surface.

11. The backlight module of claim 10, wherein the light emitting surface of the light diffusion element is a rough surface.

12. The backlight module of claim 1, wherein the part of the light reflected from each transflective film and reaching the light diffusion plate has a same light intensity.

13. The backlight module of claim 1, wherein the light guide plate comprises a first clamp portion and a second clamp portion, the first clamp portion and the second clamp portion are made of transparent materials, the first clamp portion has a first side surface, the second clamp portion has a second side surface facing towards the first side surface, and each of the transflective films is located between the first side surface and the second side surface.