CN1580900A - Back light assembly - Google Patents

Abstract

A backlight module, which includes at least two LED light sources and a light guide plate, the light guide plate includes at least a light incident surface, a light exit surface and a bottom surface, the bottom surface is perpendicular to the light incident surface and opposite to the light exit surface, the at least Two LED light sources are arranged relative to the at least one light incident surface, and the light exit surface has a plurality of prism structures perpendicular to the light incident surface, and the prism period of the prism structures is constant, wherein, the distribution mode of the prism structures is: two LED light sources The prism width of the prism structure corresponding to the position is equal to the prism period, and the prism width of the prism structure corresponding to the position between the two LED light sources gradually decreases.

Description

Backlight module

【Technical field】

The invention relates to a backlight module.

【Background technique】

Liquid crystal display is a non-self-luminous display device, and its display is mainly realized by controlling the passage or non-passage of the light beam emitted by the external light source, so a corresponding backlight module or front light module is required, and the backlight or front light module can be The light beam emitted by the external light source is guided to the display panel to realize the display function.

Please refer to FIG. 1 , which is a prior art backlight module 1 , which includes two LED light sources 11 , a reflector 12 , a light guide plate 13 , a diffusion plate 14 and a brightness enhancing sheet 15 . The light guide plate 13 is substantially flat and includes a light incident surface 131 , a bottom surface 133 and a light exit surface 132 . Wherein the light source 11 is disposed relative to the light incident surface 131 of the light guide plate 13 , and the reflection plate 12 , the light guide plate 13 , the diffuser plate 14 and the brightness enhancement sheet 15 are stacked in sequence. The light beam emitted by the light source 11 is directed to the brightness enhancement sheet 15 after being acted on by the light guide plate 13, the reflection plate 12 and the diffusion plate 14. The surface of the brightness enhancement sheet 15 is evenly distributed with a plurality of parallel prism structures 151, and the prism structure 151 directs the light beam Gather and guide the display panel (not shown). However, the number of components used in the backlight module 1 is large and each component is discrete, so the loss of light energy is relatively large, the luminance of the backlight module 1 is low, and the price of the brightness enhancing sheet 15 is relatively high, resulting in the backlight Module 1 costs more.

Please refer to FIG. 2 . In order to overcome the above disadvantages, the prior art provides another backlight module 2 , which includes two LED light sources 21 , a reflector 23 and a light guide plate 20 . A plurality of prism structures 222 are distributed on the light emitting surface 202 of the light guide plate 20 , and dot structures 221 are distributed on the bottom surface 203 of the light guide plate 20 . Wherein the light source 21 is arranged relative to the light incident surface 201 of the light guide plate 20 , and the reflection plate 23 and the light guide plate 20 are stacked. The backlight module 2 with this structure can save the cost of the brightening film, but, because the prism structure 222 arranged in parallel is integrally formed with the transparent substrate 22 of the light guide plate 20, the prism structure 222 is evenly distributed on the surface of the light guide plate 20, and the prism structure 222 only has The concentrating effect cannot change the luminance difference between the near end and the far end of the light source, so the uniformity is poor, and it is easy to form a dark band between the two light sources, which affects the visual effect.

【Content of invention】

In order to overcome the problem of poor light emitting uniformity of the backlight module in the prior art, the present invention provides a backlight module with higher light emitting uniformity.

The technical solution adopted by the present invention to solve the problems of the prior art is to provide a backlight module, which includes at least two LED light sources and a light guide plate, the light guide plate includes at least a light incident surface, a light exit surface and a bottom surface, The bottom surface is perpendicular to the light incident surface and opposite to the light exit surface, the at least two LED light sources are arranged opposite to the at least one light incident surface, the light exit surface has a plurality of prism structures perpendicular to the light incident surface, and the prism period of the prism structure is constant , wherein the distribution of the prism structure is as follows: the prism width of the prism structure corresponding to the two LED light source positions is equal to the prism period, and the prism structure corresponding to the middle position of the two LED light source positions from the two LED light source positions The prism width gradually decreases.

Compared with the prior art, the present invention has the following advantages: the light emitting surface of the light guide plate of the backlight module of the present invention has a plurality of prism structures perpendicular to the light incident surface, and the prism period of the prism structure is constant, corresponding to the prism between two LED light sources. As the width becomes smaller, the structure can reduce the dark band region, thereby improving the light emitting uniformity of the light emitting surface, and further improving the light emitting uniformity of the backlight module.

【Description of drawings】

FIG. 1 is an exploded perspective view of a prior art backlight module.

Fig. 2 is a perspective view of another backlight module in the prior art.

Fig. 3 is a polar coordinate distribution diagram of LED light intensity in the prior art.

FIG. 4 is a perspective view of the first embodiment of the backlight module of the present invention.

FIG. 5 is a front view of the backlight module shown in FIG. 4 .

Fig. 6 is a front view of the second embodiment of the backlight module of the present invention.

Fig. 7 is a polar coordinate distribution diagram of LED light intensity according to the present invention.

【Detailed ways】

Please refer to FIG. 4 and FIG. 5 together, which are respectively a perspective view and a front view of the first embodiment of the backlight module of the present invention. The backlight module 3 includes two LED light sources 31 and a light guide plate 30 . Wherein, the light guide plate 30 is used to receive the light beams from the two LED light sources 31 and lead them out. It has a light incident surface 301, a light exit surface 302, and a On the opposite bottom surface 303 , the bottom surface 303 is uniformly provided with a plurality of dots 34 .

Wherein, the light output surface 302 has a plurality of prism structures 33 perpendicular to the light incident surface, the prism period T of the prism structures 33 is constant, and the prism width B changes, and the distribution method is: the prism structures corresponding to the two LED light sources 31 The prism width B is equal to the prism period T, and the prism width gradually decreases from the two LED light sources 31 to the corresponding prism structure in the middle of the two LED light sources, and the minimum prism width is 1/3 of the prism period T.

The two LED light sources 31 are arranged relative to the light incident surface 301. The light incident surface 301 is used to receive the light beams emitted by the two LED light sources 31. Face 302 guides the beam out.

Because the light collection effect of the prism structure 33 is similar to the principle that the ratio of the prism period T to the prism width B is approximately linear, through the correction of the LED beam by the above structure, a schematic diagram of the LED equivalent optical path as shown in Figure 7 can be formed. In the prior art backlight module structure, the light beam is more concentrated (refer to FIG. 3 ), and the brightness of the light beam between the light sources is enhanced. Therefore, the dark band area can be reduced, and the light uniformity of the backlight module can be effectively improved.

Please refer to FIG. 6 , which is a front view of the second embodiment of the backlight module of the present invention. The backlight module 4 includes three LED light sources 41 and a light guide plate 40 . Wherein, the light guide plate 40 is used to receive and guide the light beams from the three LED light sources 41, and has a light incident surface 401, a light exit surface 402, and a light incident surface 401 perpendicular to the light exit surface 402. The bottom surface 403 of the bottom surface 403 is uniformly provided with a plurality of dots 44 .

Wherein, the light emitting surface 402 has a plurality of prism structures 43 perpendicular to the light incident surface 401, the prism period T of the prism structures 43 is constant, and the prism width B changes, and its distribution method is: two adjacent LED light sources 41 correspond to The prism width B of the prism structure is equal to the prism period T, and the prism width B of the corresponding prism structure gradually decreases from the two LED light sources 41 to the middle of the two LED light sources, and the minimum prism width B is 1/3 of the prism period T .

The three LED light sources 41 are arranged relative to the light incident surface 401. The light incident surface 401 is used to receive the light beams emitted by the three LED light sources 41. Face 402 guides the beam out.

Because the light collection effect of the prism structure 43 is similar to the principle that the ratio of the prism period T to the prism width B is approximately linear, through the correction of the LED beam by the above structure, a schematic diagram of the LED equivalent optical path as shown in Figure 7 can be formed. In the prior art backlight module structure, the light beam is more concentrated (refer to FIG. 3 ), and the brightness of the light beam between the light sources is enhanced. Therefore, the dark band area can be reduced, and the light uniformity of the backlight module can be effectively improved.

The material used for the plurality of dots arranged on the bottom surface of the light guide plate of the backlight module of the present invention is a highly divergent light substance, and its shape can be circular, square or rhombus, and its distribution method can also gradually increase its size along the distance from the light incident surface. or density. At the same time, a reflection plate can be arranged opposite to the bottom surface of the light guide plate, and the reflection plate can reflect the light beam leaked from the light guide plate into the light guide plate, so as to improve the luminance of the light-emitting surface of the light guide plate. The reflective plate can also be a reflective film, and the reflective film is pasted on the bottom surface of the light guide plate. Moreover, the bottom surface of the light guide plate may also obliquely intersect with the light incident surface. The number of LED light sources in the backlight module can also be more than three.

Claims (9)

1. A backlight module comprising at least two LED light sources and a light guide plate, the light guide plate comprising at least one light incident surface, a light exit surface and a bottom surface, the bottom surface is perpendicular to the light incident surface and opposite to the light exit surface, The at least two LED light sources are arranged relative to the at least one light incident surface, the light exit surface has a plurality of prism structures perpendicular to the light incident surface, and the prism period of the prism structure is constant, and it is characterized in that: the distribution mode of the prism structures is: The prism widths of the prism structures corresponding to the positions of the two LED light sources are equal to the prism period, and the prism widths of the prism structures corresponding to the intermediate positions of the two LED light sources gradually decrease from the positions of the two LED light sources. 2. The backlight module according to claim 1, wherein the prism structure of the light-emitting surface of the light guide plate corresponding to the middle position of the two LED light sources has a minimum prism width of 1/3 of the prism period. 3. The backlight module as claimed in claim 1, wherein the backlight module further comprises a reflector, and the reflector is disposed adjacent to the bottom surface of the light guide plate. 4. The backlight module according to claim 1, wherein the backlight module further comprises a reflective film, and the reflective film is attached to the bottom surface of the light guide plate. 5. The backlight module as claimed in claim 1, wherein the bottom surface is perpendicular to the light incident surface. 6. The backlight module according to claim 1, wherein a plurality of dots are evenly distributed on the bottom surface. 7. The backlight module according to claim 1, wherein the bottom surface obliquely intersects with the light incident surface. 8 . The backlight module according to claim 1 , wherein a plurality of dots are distributed on the bottom surface, and the distribution of the dots becomes denser along the direction away from the light-incident surface. 9. The backlight module according to claim 1, wherein a plurality of dots are distributed on the bottom surface, and the dots of the plurality of dots gradually become larger along a direction away from the light-incident surface.

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