CN1609681A - Backlight module - Google Patents

Abstract

The back light module includes at least one point light source and one light guiding board. The light guiding board includes at least one light incoming plane and one light outgoing plane. The point light source is set corresponding to the light incoming plane, the light outgoing plane has several notches in the place near the light incoming plane, and the interval between two notches near the point light source is greater that between two notches far from the point light source.

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】

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 disclosed in U.S. Patent No. 6,072,551. The backlight module 1 includes at least one point light source 11, a reflector 12, and a light guide plate 13. The light emitting surface 132 of the light guide plate has a plurality of equally spaced grooves 135 near the point light source 11 , and the grooves 135 are used to gather the incident light entering the light guide plate 11 to make the light emitted from the emitting surface 132 more concentrated.

Please refer to FIG. 2 , which is a polar coordinate distribution diagram of the light intensity of the point light source 11 . The light intensity in the middle part of the emitted light from the point light source 11 is the highest, and the light intensity gradually decreases from the middle to the two sides, so the emitted light energy of the point light source 11 presents a conical distribution. Please refer to FIG. 3 , which is a schematic diagram of the energy distribution of the light emitted by the two point light sources 11 on the spatial plane 200 of the light guide plate 13 . When the outgoing light of the point light source 11 is incident on a spatial plane 200, there will be regions 261, 262 and 263 in the spatial plane 200 that the outgoing light cannot reach. These regions 261, 262 and 263 are generally called dark band regions. Therefore, in FIG. 1 , although the light-emitting surface 132 of the light guide plate 13 has a plurality of grooves 135, the grooves 135 can converge light beams but cannot eliminate the dark band area, and the non-directly irradiated part of the light guide plate 13 near the point light source 11 will be There is a dark band area (not shown in the figure), which leads to a dark band area on the light-emitting surface of the light guide plate corresponding to the dark band area, thereby affecting the uniformity of light output of the backlight module 1 .

【Content of invention】

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

The technical solution adopted by the present invention to solve the existing problems is: the backlight module of the present invention includes at least one point of light source and a light guide plate, the light guide plate includes at least one light incident surface and one light exit surface, and the at least one point of light source is respectively opposite to the at least one light source. A light incident surface is provided, and the light exit surface has a plurality of grooves near the light incident surface, wherein the distance between the grooves close to the point light source is larger than the distance between the grooves far away from the point light source.

Compared with the prior art, since the light emitting surface of the light guide plate of the backlight module of the present invention has a plurality of grooves perpendicular to the light incident surface, and the distances between the grooves and the point light source are different, the arrangement thereof is also different. The distance between the grooves at the light source is wider, and the distance between the grooves away from the point light source is narrower. This design can make the light beam near the point light source more concentrated than the light beam far away from the point light source. Therefore, the structure The dark band of the light guide plate can be weakened to further reduce the difference between light and dark, thereby improving the light uniformity of the backlight module.

【Description of drawings】

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

Figure 2 is a polar coordinate distribution diagram of the light intensity of a point light source.

FIG. 3 is a schematic diagram of the optical path of the backlight module in FIG. 1 .

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

Fig. 5 is a side view of the first embodiment of the backlight module of the present invention.

FIG. 6 is a perspective view of the second embodiment of the backlight module of the present invention.

【Detailed ways】

Please refer to FIG. 4 and FIG. 5 , which are respectively a perspective view and a side view of the first embodiment of the backlight module of the present invention. The backlight module 3 includes point light sources 31 and a light guide plate 33 . Wherein, the light guide plate 33 is used to receive the light beam emitted from the point light source 31 and lead it out, it has a light incident surface 331, a light exit surface 332 and a bottom surface perpendicular to the light incident surface 331 and opposite to the light exit surface 332 333 , the bottom surface 333 is uniformly provided with a plurality of grid dots 3331 , the purpose of the multiple grid dots 3331 is to scatter the light incident on the bottom surface 333 , so that the light from the exit surface 332 can be emitted uniformly. Wherein, the light-emitting surface 332 has a plurality of grooves 3321 near the light-incident surface, and the distance L between the grooves 3321 near the point light source 31 (that is, the bright band area) is greater than that far away from the point light source 31 (that is, the dark band area). The distance between the grooves is H. The groove 3321 can be a straight groove or an arc groove, and its cross section can be V-shaped or U-shaped. Among them, the best design is to use an arc groove with a length of 3 mm. The depth is 30m, the width is 60μm, the corresponding radius of the arc groove is 10cm, the distance between the arc grooves in the bright band area is 120 μm, and the distance between each other in the dark band area is 70 μm. This design is to reduce the difference between light and dark. The density of the grooves in the dark area is higher than that in the bright area. The greater the density of the grooves, the stronger the light-collecting effect, so that the light-collecting effect of the dark area is greater than that of the bright area. The problem of the brightness difference between light and dark is compensated by the light collecting effect, so as to suppress the dark band and improve the light uniformity of the backlight module 3 . The arrangement of the grooves 3321 on the light-emitting surface of the present invention can also be such that the distance between the grooves gradually decreases from a place close to the point light source to a place far away from the point light source.

Please refer to FIG. 6 , which is a perspective view of the second embodiment of the backlight module of the present invention. The backlight module 4 includes a light guide plate 43 and a plurality of point light sources 41 respectively located on two sides of the light guide plate 43 . Wherein, the light guide plate 43 is used to receive the light beam from the point light source 41 and lead it out, it has two light incident surfaces 431 and a light exit surface 432, and the bottom surface 433 is uniformly provided with a plurality of dots (not shown in the figure) . The point light source 41 is arranged relative to the light incident surface 431. The two light incident surfaces 431 are used to receive the light beam emitted by the point light source 41. The bottom surface 433 scatters and reflects the light beam to the light exit surface 432. The beam is exported. Wherein, the light emitting surface 432 has a plurality of grooves 4321 near the light incident surface, and the plurality of grooves 4321 can be straight grooves or arc grooves, but the best design is to use arc grooves with a length of 3mm, the depth is 30μm, the width is 60μm, the corresponding radius of the arc groove is 10cm, the distance between the arc grooves in the bright zone area is 120μm, and the distance between the arc grooves in the dark zone area is 70μm. Compared with the backlight module in the prior art, the backlight module of the present invention can reduce the luminance difference between the dark band and the bright band, thereby improving the light uniformity of the backlight module.

The length of the grooves 3321, 4321 can expand or reduce the length, width and depth of the line segment according to the size of the light guide plate and the range of the dark area. Due to the distance between the dark band, the bright band and the light source, there is also a bright spot between the dark bands. Therefore, on the basis that the width of the dark band area is smaller than that of the bright band area, the distance between the line segments can be appropriately narrowed in the darker area of the dark band area, and the brightness difference between the bright band areas The space between the line segments in the brighter area of the belt area can be appropriately widened, thereby reducing the luminance difference between the brighter area and the darker area, thereby improving the light uniformity of the backlight module.

The material used for the dots on the bottom surface of the light guide plate of the present invention is a highly divergent light substance, and its shape can be circular, square or rhombus, and its distribution can also be such that its size or density increases gradually away from the light incident surface. At the same time, a reflection plate (not shown) can be arranged opposite to the bottom surface of the light guide plate, and the reflector plate reflects the light beam leaked from the light guide plate into the light guide plate to increase 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. In addition, the bottom surface of the light guide plate can also obliquely intersect with the light incident surface. The number of point light sources of the backlight module can be increased or decreased according to the size of the light guide plate. The point light source adopted in the present invention is a light emitting diode (Light Emitting Diode, LED).

Claims (10)

1. module backlight, it comprises an at least one pointolite and a light guide plate, this light guide plate comprises an at least one incidence surface and an exiting surface, this at least one incidence surface setting relatively respectively of this at least one pointolite, the close incidence surface place of this exiting surface has a plurality of grooves, it is characterized in that: spacing is greater than spacing between the groove at point of distance light source place between the close groove at pointolite place.

2. module backlight as claimed in claim 1 is characterized in that: this is 120 μ m near width between the groove at pointolite place, and width is 70 μ m between the groove at point of distance light source place.

3. module backlight as claimed in claim 1 is characterized in that: this groove is an arc groove.

4. as the 3rd described module backlight of claim, wherein this camber line flute length is 3mm, and the degree of depth is 30 μ m, and width is 60 μ m, and the arc groove respective radius is 10cm.

5. module backlight as claimed in claim 1 is characterized in that: this bottom surface is distributed with a plurality of sites.

6. module backlight as claimed in claim 5 is characterized in that: the shape of this site is along becoming big gradually away from the incidence surface direction.

7. module backlight as claimed in claim 1 is characterized in that: this module backlight further comprises a reflecting plate, and the bottom surface of the contiguous light guide plate of this reflecting plate is provided with.

8. module backlight as claimed in claim 1 is characterized in that: this module backlight further comprises a reflectance coating, and this reflectance coating is covered on the bottom surface of light guide plate.

9. module backlight as claimed in claim 1 is characterized in that: this pointolite is a light emitting diode.

10. module backlight as claimed in claim 1 is characterized in that: spacing is from reducing gradually to point of distance light source place near pointolite between this groove.

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