TWI407208B - Backlight module and liquid crystal display device - Google Patents

Abstract

The backlight module of the present invention includes at least one light guide plate, at least one light emitting unit and a circuit board. The light guide plate has a main body and at least one extension portion extending from the main body. The light emitting unit is arranged adjacent to the extension portion. The circuit board is electrically connected to the light emitting unit. In addition, the present invention also provides a liquid crystal display apparatus including the above-mentioned backlight module.

Description

Backlight module and liquid crystal display device

The present invention relates to a planar light source, and more particularly to a backlight module applied to a liquid crystal display device.

The backlight module converts the light generated by the linear or point light source into a uniform planar light by the light guide plate, thereby serving as a planar light source required for the liquid crystal display. Compared with the cold cathode fluorescent lamp used in the early backlight module, the light emitting diode has obvious energy saving characteristics and has sufficient brightness. Therefore, backlight modules using light-emitting diodes as light sources are also increasing.

As shown in the first figure, a conventional backlight module 100 has a light-emitting diode 12 disposed between two light guide plates 11. The light emitting diode 12 injects light into the light guide plate 11 laterally, and the light guide plate 11 is spaced apart from the diffusion sheet 13 above the predetermined distance to form a light mixing space 14 therebetween for uniformizing the light. Use. Therefore, after the light emitted from the light-emitting diode 12 enters the light guide plate 11 and is emitted upward through the light guide plate 11, the light can be uniformly mixed in the light mixing space 14 and then enter the diffusion sheet 13 so that the diffusion sheet 13 can be evenly distributed. The ground shines upwards.

However, the presence of the light mixing space 14 causes the diffusion sheet 13 to be closer to the light guide plate 11 , resulting in an increase in the thickness of the backlight module and affecting the thickness of the liquid crystal display. . Moreover, as the maximum luminance of the light-emitting diodes is continuously increased, high-brightness light-emitting diodes are used in the backlight module of the same size, which can effectively reduce the required number of light-emitting diodes, thereby reducing manufacturing costs. And simplify the manufacturing steps. However, when the light-emitting diode 12 in the first figure uses a light-emitting diode of higher brightness, the gap 15 between the light-emitting diode 12 and the light guide plate 11 is caused, and the light-guide plate 11 is adjacent to the light-emitting diode. A portion of the region 12 has a higher light density, and thus the brightness of the diffusion sheet 13 in the region above the LED 12 is significantly higher than in other regions, and the uniform illumination cannot be achieved.

Therefore, the object of the present invention is to provide a backlight module, which can effectively solve the above problems, can not only achieve the requirement of uniform illumination, and can effectively reduce the thickness of the backlight module.

Furthermore, it is an object of the present invention to provide a liquid crystal display device having the above backlight module.

To achieve the above objective, the backlight module of the present invention comprises at least one light guide plate, at least one light emitting unit, and a circuit board. The light guide plate has a main body, and at least one extension protruding outward from a side of the main body. The lighting unit is adjacent to the extension. The circuit board is electrically connected to the light emitting unit.

In addition, the present invention further provides another backlight module, which comprises a plurality of light guide plates, a plurality of light emitting units, and a circuit board. The light guide plates are disposed at a distance from each other, and each of the light guide plates has a main body and at least one extending portion protruding outward from the main body. The light emitting units are disposed between the light guide plates and adjacent to the light guide plates. And an extension portion, the circuit board is electrically connected to the light emitting units.

In addition, the liquid crystal display device of the present invention comprises a backlight module as described above, and a liquid crystal panel disposed above the backlight module.

The invention guides and homogenizes the light by extending the laterally outwardly extending portion of the main body, and then allows the light to enter the main body, so that the main body can receive uniform brightness. Moreover, by providing a bead above the light emitting diode to fix the light emitting diode between the corresponding two light guide plates, and because the bead is disposed above the light emitting diode, the light is not directly projected onto the optical film. Bright spots or bright lines are formed to achieve uniform illumination, and the distance between the optical film and the light guide plate can be greatly shortened to reduce the thickness of the backlight module.

<Prior technology>

100‧‧‧Backlight module

11‧‧‧Light guide

12‧‧‧Lighting diode

13‧‧‧Diffuser

14‧‧‧Hybrid space

15‧‧‧ gap

<Embodiment>

200‧‧‧Backlight module

21‧‧‧Metal backplane

22, 30‧‧‧ circuit board

23‧‧‧reflector

24‧‧‧Light guide

240‧‧‧Main body

241‧‧‧Extension

242‧‧‧ side

26‧‧‧Lighting diode

27‧‧‧Lamination

270‧‧‧ strip body

271‧‧‧stop

272‧‧‧through holes

28‧‧‧Support column

29‧‧‧Optical diaphragm

300‧‧‧LCD panel

400‧‧‧Liquid crystal display device

The first figure is a schematic view of a conventional backlight module; the second figure is a cross-sectional view of a preferred embodiment of the backlight module of the present invention; the third figure is a partial cross-sectional view of the backlight module of the present invention; FIG. 5 is a partial top view of the backlight module of the present invention; FIG. 6 is a cross-sectional view of the bead of the backlight module of the present invention; and FIG. 7 is another preferred embodiment of the backlight module of the present invention. A cross-sectional view; and an eighth diagram is a schematic view of a liquid crystal display device of the present invention.

The technical content, detailed description, and efficacy of the present invention are described below with reference to the following figures:

2 and 3 are respectively a cross-sectional view and a partial cross-sectional view of a backlight module 200 according to a preferred embodiment of the present invention. The backlight module 200 includes a metal bottom plate 21, a circuit board 22 disposed on the metal base plate 21, a reflective plate 23 disposed on the circuit board 22 (see FIG. 3), and disposed on the reflective plate 23 and including a light guide plate group of the plurality of light guide plates 24, a light emitting diode 26 disposed between the light guide plates 24, a bead 27 bridging the light guide plates 24 and covering the light emitting diodes 26, and being disposed on the bead 27 The support post 28 and the plurality of optical films 29 supported by the support post 28 above the light guide plate 24. The optical film 29 may include a diffusion sheet, a brightness enhancement sheet, and the like, and is not limited thereto.

As shown in the third figure, the circuit board 22 is electrically connected to the light emitting diode 26. The light guide plates 24 are respectively disposed on opposite sides of the light emitting diode 26, so that the light emitting diodes 26 directly illuminate the light into the light guide plate 24. The reflector 23 is configured to reflect the downwardly diffused light of the light guide plate 24 back into the light guide plate 24 to improve the light usage rate. A bead 27 is disposed above the LED 26 to fix the LED between the corresponding two light guide plates. The material of the bead may be translucent or opaque to prevent the light from being directly projected onto the optical film 29. Causes bright spots or bright lines.

As shown in the fourth figure, in order to increase the ratio of the light emitted from the LED 26 into the light guide plate 24 to reduce light leakage and form a buffer to avoid bright spots, the light guide plate 24 includes a main body 240 and includes The plurality of extensions 241 protruding from the main body 240 toward the LEDs 26 are guided by the extension portion 241 to guide the light into the main body 240. Preferably, the extension 241 is perpendicular to the main body. The length in the direction is between 0.3 and 1 mm. As shown in FIG. 5, since the light-emitting diodes 26 are correspondingly disposed on the extending portion 241, the extending portion 241 can diffuse the received higher-density light as a buffer of light, thereby extending the light. Department 241 indirectly enters the motherboard The light density of the body 240 can be substantially the same as the light density of the light emitting diode 26 obliquely directed toward the side 242 of the main body 240, so that the main body 240 can receive uniform brightness at any position. In addition, the bead 27 is connected to the main body 240 of the light guide plate 24 and covers the extending portions 241 on both sides of the LED 26 to fix the LED between the corresponding two light guide plates. The bead covering the extension portion 241 also prevents light from leaking upward from the extension portion 241.

Moreover, as shown in the fourth and sixth figures, the bead 27 includes, in addition to the strip-shaped main body 270, a plurality of strips extending from the strip-shaped main body 270 and being offset from the LED 26. The blocking portion 271 and the two sides of the stopping portion 271 respectively abut against the main body 240 of the light guide plate 24, thereby stabilizing the relative position of the light guide plate 24 and the light emitting diode 26. The stopping portion 271 can prevent the light emitted by the adjacent light-emitting diodes 26 from interfering with each other, in particular, in an application in which the adjacent light-emitting diodes 26 emit different colors of light and must be lit at different times. quality. In addition, the bead 27 is formed with a plurality of through holes 272 corresponding to the LEDs 26 and offset from the stoppers 271. By controlling the size and density of the through holes 272, the uniformity of the light received by the optical film 29 can be optimized.

FIG. 7 is a cross-sectional view of a backlight module 200 according to another preferred embodiment of the present invention, which is substantially the same as the above-described preferred embodiment, except that the embodiment replaces the bead into a circuit board 30, and saves In the above preferred embodiment, the circuit board is disposed under the light emitting diode. The circuit board 30 is provided with the light-emitting diode 26 and is electrically connected to the light-emitting diode 26, and the use thereof is also the same as that of the bead, and will not be repeated.

Figure 8 is a cross-sectional view showing a liquid crystal display device 400 in accordance with a preferred embodiment of the present invention. The liquid crystal display device 400 includes the backlight module 200 of the present invention described above, and A liquid crystal panel 300 disposed above the backlight module 200 provides a uniform planar light source of the liquid crystal panel 300 by the backlight module 200.

In summary, the main body 240 can be received by the extension portion 241 protruding outwardly from the main body 240 to guide and homogenize the light, and then enter the main body 240. Brightness. In addition, a bead is disposed above the LED 26 to fix the LED 26 between the corresponding two light guide plates 24, and the bead 27 or the circuit board 30 is disposed above the LED 26. The light is not directly projected upward onto the optical film 29 to cause bright spots or bright lines. Therefore, even if a high-brightness light-emitting diode is used, the brightness of the optical film 29 in the region above the light-emitting diode 12 is not significantly higher than that in other regions, and uniform light emission can be achieved, and since Bright spots or bright lines are formed on the optical film 29, and the required light mixing space is greatly reduced, and the distance between the optical film 29 and the light guide plate 24 can be greatly shortened, thereby effectively reducing the thickness of the backlight module.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Equivalent changes and modifications made by the scope of the present invention remain within the scope of the present invention.

21‧‧‧Metal backplane

22‧‧‧ Circuit board

23‧‧‧reflector

24‧‧‧Light guide

26‧‧‧Lighting diode

27‧‧‧Lamination

272‧‧‧through holes

28‧‧‧Support column

29‧‧‧Optical diaphragm

Claims (8)

A backlight module includes: a circuit board; a plurality of light guide plates are spliced on the circuit board; a plurality of light emitting diodes are electrically connected to the circuit board, and are disposed in the splicing gaps of the light guide plates, The light guides are laterally directed toward the light guide plates; and the plurality of press strips are spanned on any of the adjacent light guide plates to prevent the light emitting diodes located under the plurality of strips from directly projecting upwards, thereby causing a bright spot or a bright line; wherein each of the light guide plates has a main body and a plurality of extending portions protruding from the main body toward the light emitting diodes, the extensions for guiding the light The light entering the side of the diode enters the main body. The backlight module of claim 1, wherein the bead is formed with a downwardly projecting stop portion that is offset from the light emitting diode and the extension portion and is offset by one side thereof The main body of the light guide plate. The backlight module of claim 2, wherein the bead is further formed with a through hole corresponding to the light emitting diode. The backlight module of claim 1, wherein the length of the extension portion in a direction perpendicular to the main body is between 0.3 and 1 mm. A backlight module comprising: a plurality of light guide plates spliced into a large-sized planar light-emitting plate body; a plurality of strip-shaped circuit boards spanning on any of the two adjacent light guide plates; and a plurality of light-emitting diodes Body, electrically connecting the strip circuit boards, and disposed on the light guides The splicing gap of the board is used for illuminating the light guide plates laterally; wherein each of the light guide plates has a main body and a plurality of extensions protruding from the main body toward the illuminating diodes The extensions are used to guide the lateral light rays of the light-emitting diodes into the main body. The backlight module of claim 5, wherein the strip-shaped circuit board is formed with a downwardly projecting stop portion, the stop portion is offset from the light-emitting diode and the extension portion and is on one side thereof The top plate is opposite to the main body of the light guide plate. The backlight module of claim 6, wherein the strip circuit board further forms a through hole corresponding to the light emitting diode. The backlight module of claim 5, wherein the length of the extension portion in a direction perpendicular to the main body is between 0.3 and 1 mm.