CN1627151A - Backlight module group - Google Patents

Abstract

This invention relates to a backlighted module set including a light conducting plate and a light source. Said light conducting plate includes a light exit face, a bottom and a light incident face, among which, the bottom and the exit face are set oppositely, said incident face and exit face are connected with the bottom and the bottom has multiple netpoints with a grating structure on them.

Description

Backlight module

【Technical field】

The invention relates to a backlight module, in particular to a backlight module applied to a liquid crystal display.

【Background technique】

The backlight module in the prior art liquid crystal display includes a light source and a light guide plate. The light source is arranged relative to the light incident surface of the light guide plate. The light source emerges. A plurality of dots are distributed on the bottom surface of the light guide plate to scatter the light transmitted inside the light guide plate, so as to improve the uniformity of the emitted light from the light guide plate. In order to improve the problem of poor light uniformity of the light guide plate, recently, the diffraction grating technology is used in the light guide plate to improve the light uniformity of the light guide plate.

For a backlight module using a diffraction grating, please refer to US Patent No. 5,703,667 issued on December 30, 1997. Please refer to FIG. 1, the backlight module 1 includes a light guide plate 2, a fluorescent lamp 4 arranged adjacent to the light incident surface 21 of the light guide plate 2, a reflector 5 arranged adjacent to the bottom surface 23 of the light guide plate 2, and a light emitting panel arranged on the light guide plate 2. The diffusion plate 6 and the prism plate 7 on the side of the surface 22. The bottom surface 23 of the light guide plate 2 has a grating area 231 arranged in a single direction and parallel to the fluorescent lamp 4, and the ratio of the grating area 231 to the non-grating area 232 within a unit length is changed along the direction away from the fluorescent lamp 4, and the light is diffracted by the diffraction grating structure. The effect improves the light uniformity of the light guide plate 2 .

However, the light diffraction efficiency of the bottom surface 23 of the light guide plate 2 is not enough, that is, the grating area 231 of the bottom surface 23 of the light guide plate 2 is not continuously distributed, and the non-grating area 232 will not diffract the incident light, and the grating area 231 and the grating area 231 that does not diffract will not The distribution of the diffractive non-grating area 232 makes the scattering of the light on the bottom surface 23 uneven, thereby affecting the uniformity of light output from the light output surface 22 of the light guide plate.

【Content of invention】

In order to overcome the defect of uneven light output of the prior art backlight module, the present invention provides a backlight module with higher light output uniformity.

The technical solution of the present invention to solve the technical problem is to provide a backlight module, which includes a light guide plate and at least one light source. Relatively arranged, the light-incident surface is in contact with the light-emitting surface and the bottom surface, and the bottom surface is provided with a plurality of dots, and the dots have a grating structure.

Compared with the prior art, the plurality of dots on the bottom surface of the light guide plate of the present invention has a grating structure, and the grating structure can be designed in different directions, so that incident light in different directions can be diffracted, and the diffraction units are continuously distributed and cover the entire bottom surface, The brightness of each place on the bottom surface of the light guide plate can be made uniform, that is, there is a sufficiently high uniformity of light output.

【Description of drawings】

FIG. 1 is a schematic diagram of a prior art backlight module.

FIG. 2 is a schematic perspective view of the first embodiment of the backlight module of the present invention.

FIG. 3 is a schematic diagram of distribution of dots and grating structures in the first embodiment of the backlight module of the present invention.

FIG. 4 is a schematic plan view of the second embodiment of the backlight module of the present invention.

FIG. 5 is a schematic diagram of distribution of dots and grating structures of the second embodiment of the backlight module of the present invention.

【Detailed ways】

Please refer to FIG. 2 and FIG. 3 , which are respectively a three-dimensional schematic diagram of the first embodiment of the backlight module of the present invention and a schematic diagram of distribution of dots and grating structures. The backlight module 10 includes a line light source 11 , a light guide plate 12 and a reflection sheet 13 . Wherein, the line light source 11 is a cold cathode fluorescent lamp (Cold Cathode Fluorescent Lamp, CCFL), the light guide plate 12 includes a light-emitting surface 123 and a bottom surface 122 which is arranged opposite to the light-emitting surface 123 and has a plurality of dots 124, one and The light-emitting surface 123 is in contact with the light-incident surface 121 with the bottom surface 122 . The line light source 11 is disposed adjacent to the light incident surface 121 of the light guide plate 12 , and the reflection sheet 13 is disposed opposite to the bottom surface 122 of the light guide plate 12 .

The light guide plate 12 is flat and made of transparent materials such as acrylic resin, polycarbonate, polyethylene resin or glass. The size and density of dots 124 on the bottom surface 122 vary according to the distance from the line light source 11. The farther away it is from the light source, the larger and denser it will be. The plurality of dots 124 can be in the shape of microlenses, cylinders and cubes. The dots 124 are formed integrally with the light guide plate 12 by die-casting technology. The dots 124 are provided with a grating structure 125. The patterns on the surface of the mold core corresponding to the dots 125 and the dots 124 are made by electron beam etching, electroforming, etc. A series of semiconductor manufacturing processes are produced.

Please refer to FIG. 3 , which illustrates the arrangement direction of the grating structure 125 of the dots 124 . According to the luminous characteristics of the line light source 11, the light intensity along the length direction (vertical direction) of the line light source 11 is basically the same, so the arrangement direction of each grating structure 125 is parallel to the light incident surface 121, and the longitudinal dots 124 have the same size. Along the transverse direction perpendicular to the line light source 11, the farther away from the line light source 11, the weaker the light intensity is. Since the arrangement of the dots 124 along the transverse direction gradually becomes larger and denser, the area of the grating structure 125 arranged on it also gradually increases, so the light intensity Diffraction ability is enhanced, wherein the period of the grating structure 125 is 2-5 μm.

In the backlight module 10, the light emitted from the line light source 11 enters the light guide plate 12 from the light incident surface 121 of the light guide plate, part of the light is directly emitted from the light exit surface 123 of the light guide plate 12, and the other part of the light is scattered through the dots 124 and The grating structure 125 is further diffracted to form uniform light emitted from the light-emitting surface 123 of the light guide plate 12 , so that the luminance of the light-emitting surface 123 of the light guide plate is consistent everywhere, that is, there is a sufficiently high light uniformity.

Please refer to FIG. 4 and FIG. 5 , which are the second embodiment of the backlight module of the present invention. The backlight module 20 includes a point light source 21 , a light guide plate 22 and a reflector 23 . Wherein the point light source is a light emitting diode (Light Emitting Diode, LED), and the light guide plate 22 includes a light-emitting surface 223, a bottom surface 222 which is arranged opposite to the light-emitting surface 223 and has a plurality of dots 224, and a bottom surface 222 which is connected to the light-emitting surface 223 and the light-emitting surface 223. The bottom surface 222 is in contact with the light incident surface 221 . The point light source 21 is disposed adjacent to the middle of the light incident surface 221 of the light guide plate 22 , and the reflection sheet 23 is disposed opposite to the bottom surface 222 of the light guide plate 22 .

The light guide plate 22 is wedge-shaped, and the size and density of the plurality of dots 224 on the bottom surface 222 vary according to the distance from the light source. The plurality of dots 224 are integrally formed with the light guide plate 22 , and the plurality of dots 224 have a grating structure 225 thereon.

Referring to FIG. 5 , the grating arrangement direction of the grating structure 225 will be described. Since the point light source 21 has a certain dispersion angle, the grating arrangement direction of the grating structure 225 on the dot 224 is set according to the incident direction of the light emitted by the point light source 21 . The gratings of the grating structure 225 are arranged along a direction substantially perpendicular to the incident light, so as to obtain the best diffraction effect. The grating period of the grating structure 225 is 2-5 μm. Of course, the arrangement direction of the gratings in the grating structure 225 can also be designed differently according to the positions and numbers of the point light sources.

In addition, the backlight modules 10, 20 can also have other changes in design, which can change the grating period of each grating structure 125, 255, thereby changing the diffraction efficiency of each grating structure 125, 255 to achieve the purpose of uniform light output, such as changing the grating period The distance from the light source 32 makes it smaller; the dots 124 of the light guide plate 22 can also be evenly distributed on the bottom surface 122 , and the dots 124 can also be the same size.

Claims (8)

1. A backlight module, comprising a light guide plate and at least one light source, the light guide plate comprising a light exit surface, a bottom surface and at least one light incident surface, wherein the bottom surface is opposite to the light exit surface, the light entrance surface and the light exit surface The surface and the bottom surface are connected, and the feature is that: the bottom surface is provided with a plurality of dots, and the dots are provided with a grating structure. 2. The backlight module according to claim 1, wherein the size of the dots increases gradually along the direction away from the light source. 3. The backlight module according to claim 1, wherein the density of the dots increases gradually along the direction away from the light source. 4. The backlight module according to claim 1, wherein the grating period of the grating structure is 2-5 μm. 5. The backlight module according to claim 1, wherein the grating arrangement direction of the grating structure is perpendicular to the incident light. 6. The backlight module according to claim 1, wherein the grating period of the grating structure gradually becomes smaller along the direction away from the light source. 7. The backlight module according to claim 1, wherein the dots are evenly distributed. 8. The backlight module according to claim 1, wherein the dots have the same size.

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