CN101676620A - Liquid crystal display device, backlight module and light-emitting unit - Google Patents

Abstract

A light-emitting unit includes a light-guiding element and at least one light-emitting element. The light-guiding element has a light-entering surface, a light-emitting surface and a receiving space. The light-emitting element is received in the receiving space and is arranged adjacent to the light-entering surface. The invention also discloses a backlight module and a liquid crystal display device including the light-emitting unit.

Description

Liquid crystal display device, backlight module and light emitting unit

technical field

The invention relates to a display device, a backlight module and a light emitting unit, in particular to a liquid crystal display device, a backlight module and a light emitting unit.

Background technique

In the backlight module of a liquid crystal display device, whether the light source is a line light source (such as cold cathode fluorescent lamp, CCFL) or a point light source (such as: light-emitting diode, LED), it needs to be diffused or guided to become a surface light source. . In the process of diffusion or light guiding of point light sources, the uniformity of brightness, the mixing of colors, and the setting and use of the number of light-emitting elements will determine the quality and production cost of the backlight module and the liquid crystal display device.

Referring to FIG. 1 , a conventional backlight module 10 includes a diffuser plate 11 and a plurality of light emitting elements 12 , and the backlight module 10 is a direct type backlight module. The diffuser plate 11 is arranged on the light emitting element 12. The existing light emitting element 12 is a light emitting diode, and most of its high-intensity light is concentrated within a certain range of emission angles to become a point light source. The diffusion plate 11 is a composite structure in which a mother plate is doped with a plurality of diffusion particles, and has a light incident surface 11 a and a light exit surface 11 b. The light emitting element 12 is disposed under the light incident surface 11a. When the light emitted by the light emitting element 12 is incident on the light incident surface 11a, diffused randomly by the diffuser plate 11 and emitted from the light exit surface 11b, a surface light source that is more uniform than the original point light source is formed.

However, the light-emitting elements 12 directly exit the light-emitting surface 11b through the diffuser plate 11, and it is still easy to see dot-like bright lines from the liquid crystal display device. In addition, the emitted light intensity of the light outside a certain angle in the side direction drops sharply, although each light-emitting element 12 The light is diffused through the diffuser plate 11 directly above, and the effect of light mixing and uniformity is still limited. In addition, in the prior art, in order to prevent the relatively dark area at the boundary between the light emitting elements 12 from being too obvious, the distance between the light emitting elements 12 must be kept close to a certain degree and cannot be enlarged. Therefore, not only the number of the existing light-emitting elements 12 cannot be reduced, but also the surface light source with dotted bright lines also causes poor display quality of the liquid crystal display device.

Therefore, how to provide a liquid crystal display device, a backlight module and a light-emitting unit to improve the bright streak phenomenon of the light source, increase the light mixing efficiency, and reduce the number of light-emitting elements used, thereby increasing the display quality of the liquid crystal display device and Reducing production costs has become one of the important issues.

Contents of the invention

In view of the above-mentioned problems, the object of the present invention is to provide a liquid crystal display device, a backlight module and a light-emitting unit. Through the arrangement of light-guiding elements, the light-emitting light source can increase the light mixing efficiency, improve the light uniformity, avoid bright lines and reduce the usage of light-emitting elements. , thereby increasing the display quality of the liquid crystal display device and reducing the production cost.

To achieve the above purpose, a light emitting unit according to the present invention includes a light guide element and at least one light emitting element. The light guide element has a light incident surface, a light exit surface and an accommodating space. The light-emitting element is accommodated in the accommodating space and adjacent to the light-incident surface.

To achieve the above purpose, a backlight module according to the present invention includes a circuit board and a plurality of light emitting units. The light emitting unit is arranged on the circuit board and electrically connected with the circuit board. Each light emitting unit includes a light guide element and at least one light emitting element. The light guide element has a light incident surface, a light exit surface and an accommodating space. The light emitting element is accommodated in the accommodating space and adjacent to the light incident surface.

To achieve the above purpose, a liquid crystal display device according to the present invention includes a liquid crystal display panel and a backlight module. The backlight module is arranged corresponding to the liquid crystal display panel, and has a circuit board and a plurality of light emitting units. The light emitting unit is arranged on the circuit board and electrically connected with the circuit board. Each light emitting unit includes a light guide element and at least one light emitting element. The light guide element has a light incident surface, a light exit surface and an accommodating space. The light emitting element is accommodated in the accommodating space and adjacent to the light incident surface.

Based on the above, according to a liquid crystal display device, a backlight module, and a light emitting unit of the present invention, the light from the light source increases in positive direction by setting a guide angle, a semi-transmissive and semi-reflective film, a scattering structure, an arc or a cone structure on the light guide element. And the effect of lateral uniform diffusion. Compared with the prior art, the invention can increase the light mixing efficiency of the light source, improve the uniformity of light, avoid the generation of bright lines and reduce the usage of light emitting elements, thereby increasing the display quality of the liquid crystal display device and reducing the production cost.

Description of drawings

FIG. 1 is a schematic diagram of a backlight module of an existing LED light source;

2A and 2B are schematic diagrams of a backlight module according to a first embodiment of the present invention;

3 is a schematic diagram of a backlight module according to a second embodiment of the present invention;

4 is a schematic diagram of a backlight module according to a third embodiment of the present invention;

5A and 5B are schematic diagrams of a backlight module according to a fourth embodiment of the present invention;

6 is a schematic diagram of a backlight module according to a fifth embodiment of the present invention; and

FIG. 7 is a schematic diagram of a liquid crystal display device incorporating a preferred embodiment of the present invention.

Detailed ways

A liquid crystal display device, a backlight module and a light emitting unit according to preferred embodiments of the present invention will be described below with reference to related drawings, wherein the same elements will be described with the same reference symbols.

first embodiment

Referring to FIG. 2A and FIG. 2B , a backlight module 20 according to the first embodiment of the present invention includes a circuit board 22 and a plurality of light emitting units 21 (only one is shown in the figure). The backlight module 20 can be a direct type backlight module or an edge type backlight module. In this embodiment, the backlight module 20 is described by taking a direct type backlight module as an example. The light emitting unit 21 is disposed on the circuit board 22 and is electrically connected to the circuit board 22 . Each light emitting unit 21 includes a light guide element 211 and at least one light emitting element 212 . The light emitting element 212 is, for example but not limited to, a light emitting diode or an organic light emitting diode (OLED) light emitting element. The light guide element 211 is a lens structure, and has a light incident surface 211a, a light exit surface 211b and an accommodating space 211c. The light emitting element 212 is accommodated in the accommodating space 211c and adjacent to the light incident surface 211a. The shape of the light-incident surface 211 a matches the shape of the light-emitting element 212 , or the shape of the light-incident surface 211 a matches the shape of the package of the light-emitting element 212 . The light incident surface 211a is, for example but not limited to, an upward convex surface or an upward concave surface. In this embodiment, the light incident surface 211a is a ㄇ-shaped tapered surface protruding upward. In addition, there is a transparent optical glue G between the light-emitting element 212 and the light-incident surface 211a, and its refractive index is between the refractive index of the light-emitting element 212 and the refractive index of the light-guiding element 211, so that the loss during light transmission is reduced. to a minimum. In this embodiment, at least one chamfer 214 is disposed on the light emitting surface 211 b above the light emitting element 212 . In addition, a plurality of dots 213 or microstructures such as V-cuts (not shown) are provided on the opposite side of the light-emitting surface 211b.

It should be noted that the light-emitting element 212 of the present invention can be directly accommodated in the accommodating space 211c by a package containing a light-emitting diode chip, or can be accommodated in the accommodating space 211c with a bare light-emitting diode chip, or can be exposed through a light-emitting diode. The chip is directly packaged with the light guide element 211 and electrically connected to the circuit board 22 by flip-chip bonding or wire bonding.

When the light L from the light-emitting unit 21 is transmitted to the light-emitting surface 211b, due to the setting of the chamfer 214, the light L emitted from the light-emitting element 212 can be concentrated and totally reflected by the chamfer 214 through proper angle design using the law of refraction. reflected to the dot 213 in a way, through the dot 213, the ability to continue total reflection and conduction to the side is destroyed, and the light L is led out from the light-emitting surface 211b, so as to avoid the high-intensity light from directly above the light-emitting element 212 and generate a dot light streaks.

second embodiment

Referring to FIG. 3, a backlight module 30 of the second embodiment of the present invention includes a circuit board 32 and a plurality of light emitting units 31. Most of its basic structure is the same as that of the backlight module 20 of the first embodiment. Let me repeat. The difference between the backlight module 30 and the backlight module 20 is that the light-emitting unit 31 can only be provided with a semi-transmissive and semi-reflective film 315 in a local area directly above the light-emitting element 312 without setting a chamfer, and the material of the semi-transmissive and semi-reflective film 315 can be Multilayer film with both light transmission and reflection properties.

As shown in Figure 3, when the light L of each light-emitting unit 31 is transmitted to the light-emitting surface 311b, a semi-transmissive and semi-reflective film 315 is provided so that the light-emitting element 312 directly emits the light L directly above and near directly above, wherein the light-emitting element Part of most of the light L emitted by 312 is directly transmitted through the light-emitting surface 311b, and the other part is reflected around the light-guiding element 311, and then passes through the network point 313 to continue the total reflection of the light L to the side and destroy the transmission ability, so that the light L is emitted from the light-emitting surface. 311b, so that too much high-intensity light can be directly emitted directly above and near the light-emitting element 312 to cause bright lines, and it will not cause the lack of directly transmitted light L directly above the light-emitting element 312, resulting in local dark zone. In this way, the lighting effect of the backlight module 30 can be made more uniform.

third embodiment

Referring to FIG. 4 , the basic structure of a backlight module 40 according to the third embodiment of the present invention has been described in detail in the backlight module 20 of the first embodiment above, so it will not be repeated here. Except that the light emitting unit 41 is the same as the light emitting unit 21 of the first embodiment, the light emitting unit 41 still has a plurality of chamfers 414 located on the light emitting element 412 and on the sides of the light guiding element 411 . The light L passing through the guide angle 414 on the side of the light guide element 411 destroys the ability of the light L to continue total reflection and conduction, so that it is emitted from the surface of the guide angle 414, which not only enhances the color mixing effect between the light emitting units 41, but also can The gap between each light emitting unit 41 is increased, and the number of light emitting elements 412 is reduced.

Fourth embodiment

Referring to FIG. 5A and FIG. 5B , it is a backlight module 50 according to the fourth embodiment of the present invention. The basic structure of the light emitting units 51 a and 51 b is the same as that of the light emitting unit 41 of the above third embodiment.

As shown in FIG. 5A, the light emitting unit 51a differs from the light emitting unit 41 in that: the light incident surface 511a is a circular arc surface, so that not only the light emitting element 512 is easier to emit light, but also the light from the light emitting element 512 can be reduced (not shown in the figure) The loss when entering the light guide element 511, and the light incident surface 511a of the light guide element 511 is easier to shape.

As shown in FIG. 5B , on the light incident surface 511 a ′, a scattering structure 516 , such as a plurality of diffusing particles, can also be added to make the light L scattered at a larger angle, and the output of the light L is more uniform.

fifth embodiment

Referring to FIG. 6 , a backlight module 60 according to the fifth embodiment of the present invention includes a circuit board 62 and a light emitting unit 61 . Among them, the light guide element 611 of the light emitting unit 61 is different from the above-mentioned embodiments in that: the light incident surface 611a has a semi-transmissive and semi-reflective tapered surface, and its apex is directly facing the light-emitting element 612, which is designed to replace the above-mentioned embodiments. The chamfer design of the example can still avoid bright lines.

Referring to FIG. 7 , a liquid crystal display device 7 according to a preferred embodiment of the present invention includes a liquid crystal display panel 70 and a backlight module 80 . The backlight module 80 is disposed corresponding to the liquid crystal display panel 70 . The composition of the backlight module 80, except that the LED light source module 81 composed of the light emitting unit and the circuit board of the above-mentioned embodiments can be applied (a plurality of circular pie-shaped elements shown in FIG. 7 are a plurality of light emitting units), the backlight module 80 also includes an optical film set 82 adjacent to the light emitting surface of the light emitting unit. The optical film set 82 is composed of, for example, an upper diffusion film 821 , a brightness enhancement film 822 and a lower diffusion film 823 to provide a uniform light source without bright streaks for the liquid crystal display device 7 .

In summary, according to the liquid crystal display device, backlight module and light-emitting unit of the present invention, the light from the light source increases positively by setting guide angles, semi-transmissive and semi-reflective films, scattering structures, arcs or cone structures on the light guide elements. The effect of uniform diffusion in the direction and side. Compared with the prior art, the invention can increase the light mixing efficiency of the light source, improve the uniformity of light, avoid the generation of bright lines and reduce the usage of light emitting elements, thereby increasing the display quality of the liquid crystal display device and reducing the production cost.

The foregoing descriptions are illustrative only, not limiting. Any equivalent modifications or changes made without departing from the spirit and scope of the present invention shall be included in the appended claims.

Claims (20)

1. A light emitting unit, comprising: The light guide element has a light incident surface, a light exit surface and an accommodating space; and At least one light emitting element is accommodated in the accommodating space and adjacent to the light incident surface. 2. The light emitting unit according to claim 1, wherein the light guide element has at least one guide angle disposed on the light emitting surface. 3. The light emitting unit according to claim 2, wherein the guide corner is located above the light emitting element and/or at a side of the light guiding element. 4. The light emitting unit according to claim 1, wherein the light emitting surface and/or the light incident surface above the light emitting element is provided with a semi-transmissive and semi-reflective film. 5. The light emitting unit according to claim 1, wherein the light incident surface is an upwardly convex surface or an upwardly concave surface. 6. The light emitting unit according to claim 5, wherein the light incident surface is an arcuate surface or a tapered surface. 7. The light emitting unit according to claim 1, wherein the light incident surface has a scattering structure. 8. The light emitting unit according to claim 1, wherein the light guide element has a plurality of dots or microstructures disposed on the opposite side of the light emitting surface. 9. The light emitting unit according to claim 1, wherein the light emitting element is a bare chip or a light emitting package. 10. The light emitting unit according to claim 1, which is disposed on a circuit board and electrically connected to the circuit board. 11. A backlight module, comprising: circuit boards; and A plurality of light-emitting units are arranged on the circuit board and electrically connected to the circuit board. Each of the light-emitting units includes a light-guiding element and at least one light-emitting element. The light-guiding element has a light-incoming surface, a light-emitting surface, and a light-emitting element an accommodating space, the light-emitting element is accommodated in the accommodating space and adjacent to the light-incident surface. 12. The backlight module according to claim 11, wherein the light guide element has at least one guide angle disposed on the light emitting surface. 13. The backlight module according to claim 12, wherein the guide corner is located above the light-emitting element and/or at the side of the light-guiding element. 14. The backlight module according to claim 11, wherein the light-emitting surface and/or the light-incoming surface above the light-emitting element are provided with a semi-transmissive and semi-reflective film. 15. The backlight module according to claim 11, wherein the light incident surface is an upward convex surface or an upward concave surface. 16. The backlight module according to claim 15, wherein the light incident surface is an arc-shaped surface or a tapered surface. 17. The backlight module as claimed in claim 11, wherein the light incident surface has a scattering structure. 18. The backlight module according to claim 11, wherein the light guide element has a plurality of dots or microstructures disposed on the opposite side of the light emitting surface. 19. The backlight module according to claim 11, wherein the light emitting element is a bare chip or a light emitting package. 20. The backlight module of claim 11, further comprising: The optical film group is adjacent to the light emitting surface of the light emitting unit.

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