CN104121517A - Backlight module - Google Patents

Abstract

The invention relates to a backlight module. The backlight module comprises a light guide plate, a light source and an inverse prismatic lens, wherein the light guide plate is provided with an incident surface and an emergent surface, the light source is arranged on the incident surface, the inverse prismatic lens is opposite to the emergent surface and is provided with a first surface opposite to the emergent surface, a prism microstructure is formed on the first surface, and the prism microstructure is composed of multiple triangular prism protrusions which are parallel to one another and connected with one another.

Description

Backlight module

technical field

The invention relates to a backlight module, in particular to a backlight module with a relatively large lateral diffusion angle.

Background technique

Recently, liquid crystal displays have become more and more popular, and the backlight module is one of the key components of the LCD panel. Since the liquid crystal itself does not emit light, the function of the backlight module is to supply sufficient brightness and evenly distributed light source , so that it can display the image normally. At present, the backlight module has gradually changed from cold cathode ray tube (Cold Cathode Fluorescent Lamp, CCFL) to light emitting diode (Light Emitting Diode, LED). Using light emitting diode as a backlight source has the advantages of high brightness, low power consumption, and high color purity. .

At present, in the application of the LED element as the backlight module, it is mainly divided into the light-guiding type backlight type directly below the light guide plate and the light-emitting type directly below the light guide plate and the side light-emitting type. Among them, the light-incoming type directly under the light guide plate is directly under the light-emitting surface of the display panel, and the backlight is installed directly under the light-emitting surface of the display panel. Since the LED element itself is a point light source, the direct-light-emitting type backlight module is likely to produce bright spots and discoloration on the display screen. Spots or uneven light and dark areas and will increase the overall thickness of the module. In order to solve the above problems, a side light guide type backlight with side light input has been developed, that is, the LED element is placed on the side of the display area, and the point light source emitted by the LED is converted into a form by using the microstructure on the side of the light guide plate. The line light source enters the inside of the light guide plate, and the line light source transmitted inside the light guide plate converts the line light source in the horizontal direction (parallel glass) into a surface light source in the vertical direction (vertical glass) through the optical layout at the bottom of the light guide plate. The diffuser diffuses and atomizes the surface light source uniformly.

However, when multiple people watch a display device together, due to space constraints, everyone needs to watch around the display device. Since the distribution of the existing backlight modules in the horizontal direction is relatively concentrated, the display seen by the viewers located in the periphery The brightness is small, which affects the viewing effect.

Contents of the invention

In view of this, it is necessary to provide a backlight module capable of having a larger divergence angle in the lateral direction.

A backlight module, which includes a light guide plate, a light source and a reverse prism sheet, the light guide plate has a light incident surface and a light exit surface, the light source is arranged on the light incident surface, the reverse prism sheet and the light exit surface In contrast, the reverse prism sheet has a first surface opposite to the light-emitting surface, and the first surface is formed with a prism microstructure, and the prism microstructure is a plurality of triangular prism-shaped protrusions parallel to each other and connected to each other. rise.

Compared with the prior art, when the light emitted by the light source of the backlight module of this technical solution is deflected to the vertical direction through the light guide plate, since the reverse prism sheet is provided, the light is incident on the reverse prism structure, and after being emitted and refracted, it passes through the reverse prism. The second surface of the prism sheet is emitted, so that the outgoing angle of the light is shifted toward the central direction, so that the vertical divergence angle of the light source module is concentrated in the normal viewing angle, so that the display device using the backlight module has a large horizontal range. brightness.

Description of drawings

FIG. 1 is a three-dimensional schematic diagram of a backlight module of the present technical solution.

FIG. 2 is a schematic cross-sectional view of the backlight module in FIG. 1 .

FIG. 3 is a distribution diagram of the light output angles of the backlight module without the reverse prism sheet according to the technical solution.

FIG. 4 is a distribution diagram of the light output angles of the backlight module with the reverse prism sheet according to the technical solution.

Description of main component symbols

Backlight module 100 light guide plate 10 light source 20 Inverse prism sheet 30 Light incident surface 11 light emitting surface 12 groove 131 first surface 31 second surface 32 Prism Microstructure 311 Triangular prism convex 312 first side 3121 second side 3122

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

Detailed ways

Referring to FIG. 1 and FIG. 2 , the backlight module 100 provided by the first embodiment of the present invention includes a light guide plate 10 , a plurality of light sources 20 and a reverse prism sheet 30 .

The light guide plate 10 is roughly plate-shaped, and has a light incident surface 11 and a light exit surface 12 perpendicular to each other. The light incident surface 11 is opposite to the light source 20 .

The light guide plate 10 is made of a light-transmitting material, and the material of the light guide plate 10 can be polycarbonate (PC), polymethyl methacrylate (PMMA), methyl methacrylate, styrene copolymer ( MS), polyethylene terephthalate (PETG), polystyrene (PS) or a mixture of two or more of the above materials.

The light emitting surface 12 of the light guide plate 10 is formed with a diffuse microstructure. The diffusion microstructure is a plurality of hemispherical grooves 131 formed inside the light guide plate 10 from the light exit surface 12 . A plurality of grooves 131 are arranged in an array on the light emitting surface 12 of the light guide plate 10 . The diameter of the opening of each groove 131 on the light emitting surface 12 is 1 micron to 100 microns, and the distance between two adjacent grooves 131 is 1 micron to 100 microns.

It can be understood that the shape of the groove 131 is not limited to the hemispherical shape in this embodiment, and its shape can be set according to the needs of optical design, such as a semi-ellipsoid, etc., to achieve a better effect of light divergence.

The light incident surface 11 is a side surface of the plate-shaped light guide plate 10 . The plurality of light sources 20 are disposed opposite to the light emitting surface 12 . The plurality of light sources 20 are arranged at equal intervals. The light source 20 may be a light emitting diode.

It can be understood that the light incident surface 11 of the light guide plate 10 can also be provided with microstructures, such as semicircular protrusions or grooves, so as to facilitate the divergence of light incident on the light guide plate 10, so as to facilitate The light intensity in the light panel 10 is uniform. In addition, each side of the light guide plate 10 can also be used as a light incident surface, so that a light source is provided on each side, so as to increase the light output intensity of the backlight module.

The inverse prism sheet 30 is roughly plate-shaped, and is disposed on the side of the light-emitting surface 12 of the light guide plate 10 , and is disposed parallel to the light guide plate 10 . The reverse prism sheet 30 has a first surface 31 and a second surface 32 opposite to each other. The first surface 31 is opposite to the light guide plate 10 . Prism microstructures 311 are formed on the first surface 31 . The prism microstructure 311 is a plurality of triangular prism-shaped protrusions 312 parallel to each other and connected to each other, and the length direction of each triangular prism-shaped protrusion 312 is parallel to the horizontal direction. The triangular prism-shaped protrusion 312 has a first side 3121 and a second side 3122 connected to each other. The longitudinal section of each triangular prism-shaped protrusion 312 is an isosceles triangle. The first side 3121 and the second side 3122 The included angle θ between them is 60 degrees to 70 degrees, the intersection line of the first side 3121 and the second side 3122 is parallel to the first surface 31, and the intersection line of the first side 3121 and the second side 3122 is parallel to the first surface 3122. The distance H of a surface 31 is 1.3 microns to 5.5 microns.

That is to say, each triangular prism-shaped projection 312 is that one of the three sides of the triangular prism coincides with the first surface 31, and the other two sides of the triangular prism are the first side 3121 and the second side respectively. Two sides 3122. The longitudinal section of the triangular prism-shaped protrusion 312 is an isosceles triangle. The corner away from the first surface 31 is the apex of the isosceles triangle. The angle θ of the apex angle is 60 degrees to 70 degrees. The distance H between the apex of the isosceles triangle away from the first surface 31 and the first surface is 1.3 microns to 5.5 microns.

The second surface 32 of the inverse prism sheet 30 is a plane. It can be understood that, in order to achieve better optical effects, microstructures can also be fabricated on the second surface 32 as required.

Please refer to FIG. 2 , when the light emitted by the light source 20 is deflected to the vertical direction through the light guide plate 10, due to the inverse prism sheet 30, the light is incident on the prism microstructure 131, and after being refracted, the light from the inverse prism sheet 30 The second surface 32 emits light so that the outgoing angle of the light shifts toward the central direction, so that the vertical divergence angle of the light source module is concentrated in the front viewing angle, so that the display device using the backlight module has brightness in a large horizontal range.

Please refer to FIG. 3 . When the reverse prism sheet 30 is not provided, when the backlight module 100 only includes the light guide plate 10 and the light source 20 , the distribution angle of the emitted light is shown in FIG. 3 . That is, the light emitted from the backlight module 100 has a relatively large distribution angle in the forward direction of the light. Please refer to FIG. 4, when the backlight module 100 is provided with the reverse prism sheet 30, the light output angle of the backlight module 100 is in the horizontal direction, that is, parallel to the length direction of the triangular prism-shaped protrusion 312, and has a larger divergence angle, Therefore, the display device adopting the backlight module can have brightness in a relatively large range in the lateral direction.

It can be understood that those skilled in the art can also make other changes within the spirit of the present invention, which should be included within the scope of the present invention.

Claims (7)

1. a backlight module, it comprises LGP, light source and inverse edge eyeglass, described LGP has incidence surface and exiting surface, described light source is arranged at described incidence surface, described inverse edge eyeglass is relative with described exiting surface, described inverse edge eyeglass has the first surface relative with described exiting surface, and described first surface is formed with prism microstructure, and described prism microstructure is a plurality of being parallel to each other and interconnective a plurality of triangular prism shaped projection.

2. backlight module as claimed in claim 1, is characterized in that, the length direction of described each triangular prism shaped projection is parallel to horizontal direction.

3. backlight module as claimed in claim 1, it is characterized in that, described triangular prism shaped projection has interconnective the first side and the second side, and the longitudinal section of each triangular prism shaped projection is isosceles triangle, and the angle theta between described the first side and the second side is 60 degree to 70 degree.

4. backlight module as claimed in claim 3, is characterized in that, the intersection of described the first side and the second side is parallel with first surface, and described the first side and the intersection of the second side and the distance of first surface are 1.3 microns to 5.5 microns.

5. backlight module as claimed in claim 1, is characterized in that, the exiting surface of described LGP is formed with diffusion micro-structural, and described diffusion micro-structural is the groove of the formation to LGP inside from exiting surface.

6. backlight module as claimed in claim 5, is characterized in that, described groove be shaped as semicircle or half elliptic.

7. backlight module as claimed in claim 1, is characterized in that, described inverse edge eyeglass also has the second surface relative with first surface, and described second surface is plane.