CN101737725B - Backlight module and liquid crystal display - Google Patents

Abstract

The invention relates to a backlight module and a liquid crystal display. The backlight module comprises at least one point light source and a light guide plate. The light guide plate comprises a light emitting surface, a bottom surface, a light incident surface, a first side surface, a second side surface, a first microstructure and a second microstructure. The bottom surface is opposite to the light-out surface, the light-in surface is connected with the light-out surface and the bottom surface, the point light source is arranged at a position adjacent to the light-in surface, and the first microstructure is formed on the light-in surface. The first side face is opposite to the light incident face and is connected with the light emergent face and the bottom face. The second side surface is connected with the light-emitting surface, the bottom surface, the light-entering surface and the first side surface. The second microstructure is formed on the second side surface and used for reflecting the light beam incident on the second microstructure.

Description

Backlight module and liquid crystal display

technical field

The invention relates to a backlight module and a liquid crystal display including the backlight module.

Background technique

FIG. 1 is a schematic diagram of a conventional backlight module 100 using point light sources as side light sources. As shown in FIG. 1, when a point light source 102 (such as a light emitting diode) is used as a side light source, based on the light output characteristics of the point light source 102, the front end of the light guide plate 104 will generate alternately distributed bright areas (hot spot) HS and dark areas ( dark spot) DS, so it is necessary to reserve a large area of mixed light to spread the light energy uniformly, resulting in a significant reduction in the effective uniform light output area of the light guide plate 104. In order to solve this problem, as shown in FIG. 2, in another existing backlight module 200 design, a microstructure 106 can be arranged on the light-incident side of the light guide plate 104, because the light beam passing through the microstructure 106 will enlarge the incident light beam. Therefore, the bright area HS can be formed in the area of the light guide plate 104 closer to the light incident side, thereby effectively reducing the area of the light mixing area. However, as shown in FIG. 1, the lateral light beam I would originally be reflected by the side edge 104a of the light guide plate and return to the light guide plate 104. When the angle is increased, part of the side beam I' will be refracted out of the light guide plate 104, which will not only reduce the light utilization efficiency, but also when the part of the side beam I' refracted out of the light guide plate 104 encounters an external component, such as a foggy surface When the plastic frame 108 of reflective material is used, part of the side light beam I′ will be reflected by the surface of the plastic frame 108 to form an obvious side bright spot 112 .

Contents of the invention

The invention provides a backlight module and a liquid crystal display, which can effectively avoid the generation of bright spots on the side of the backlight module and have good light utilization efficiency.

An embodiment of the invention provides a backlight module including at least one point light source and a light guide plate. The light guide plate includes a light emitting surface, a bottom surface, a light incident surface, a first side, a second side, a first microstructure and a second microstructure. The bottom surface is opposite to the light-emitting surface, the light-incident surface connects the light-emitting surface and the bottom surface, the point light source is arranged at a position adjacent to the light-incident surface, and the first microstructure is formed on the light-incidence surface. The first side is opposite to the light incident surface, and connects the light exit surface and the bottom surface. The second side is connected with the light emitting surface, the bottom surface, the light incident surface and the first side. The second microstructure is formed on the second side, and is used to reflect the light beam incident on the second microstructure back into the light guide plate, wherein the second microstructure includes a plurality of pillars protruding from the second side, and wherein Each of the cylinders has a first slope and a second slope connected to the first slope, the first slope is closer to the light incident surface than the second slope, and the length of the first slope is greater than The length of the second slope, wherein the angle between the first slope and the second side is greater than or equal to 10 degrees and less than or equal to 30 degrees.

To achieve one or part or all of the above objectives or other objectives, an embodiment of the present invention provides a liquid crystal display, including a liquid crystal display panel and the above-mentioned backlight module. The backlight module is arranged on one side of the liquid crystal display panel for providing the surface light source required by the liquid crystal display panel, and the light emitting surface of the light guide plate of the backlight module faces the liquid crystal display panel.

Based on the design of each of the above embodiments, when the side beam with a large angle deflected by the microstructure on the light incident surface is incident on the side of the light guide plate, the side beam encounters the microstructure formed on the second side to meet total reflection Conditions are reflected back into the light guide plate, which can effectively avoid the situation that the side beams are refracted out of the light guide plate to form side bright spots, and the light utilization efficiency can be improved because the side beams are reflected back into the light guide plate.

Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention. In order to make the above and other objects, features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail with accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram of an existing backlight module with a point light source as a side light source;

FIG. 2 is a schematic diagram of another existing backlight module using a point light source as a side light source;

3 is a schematic side view of a liquid crystal display according to an embodiment of the present invention;

FIG. 4 is a schematic top view of some components of the backlight module in FIG. 3;

5 is a partially enlarged schematic view of a light guide plate according to an embodiment of the present invention;

6 and 7 are schematic diagrams illustrating the effect of setting microstructures on the side of the light guide plate;

8 is a schematic top view of a backlight module according to another embodiment of the present invention; and

FIG. 9 is a schematic top view of a backlight module according to another embodiment of the present invention.

[Description of main component symbols]

10 LCD display

20 LCD display panel

30 backlight module

32 Light guide plate

321 incident surface

322 light emitting surface

323 Bottom

324, 325, 326 sides

34 point light sources

36 reflector

38 optical diaphragm group

42, 44, 44a, 44b microstructure

100 backlight modules

102 point light sources

104 Light guide plate

104a Side of light guide plate

106 Microstructure

108 plastic frame

112 side highlights

200 backlight module

d Orthographic length

I, I’, R, T side beam

P column

S1 first slope

S2 second slope

S3 curved surface

θ angle

IN spacing

DS Dark Zone

HS bright area

Detailed ways

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of the embodiments with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or back, etc., are only referring to the directions of the drawings. Accordingly, the directional terms are used to illustrate and not to limit the invention.

FIG. 3 is a schematic side view of a liquid crystal display according to an embodiment of the present invention, and FIG. 4 is a schematic top view of some components of the backlight module in FIG. 3 . Referring to FIG. 3 and FIG. 4 , the liquid crystal display 10 includes a liquid crystal display panel 20 and a backlight module 30 . The backlight module 30 is, for example, a side type backlight module (side type backlight module), which is configured on one side of the liquid crystal display panel 20 to provide the surface light source required by the liquid crystal display panel 20, and includes a light guide plate 32 and at least one point light source 34 . In this embodiment, the light guide plate 32 is a wedge-shaped light guide plate, but it is not limited thereto. For example, it can also be a flat light guide plate. Furthermore, the point light source 34 can be, for example, a light emitting diode (LED).

The light guide plate 32 has a light incident surface 321 , a light exit surface 322 , a bottom surface 323 , a side surface 324 opposite to the light incident surface 321 , and two opposite side surfaces 325 , 326 . The light emitting surface 322 faces the liquid crystal display panel 20 , and the bottom surface 323 is opposite to the light emitting surface 322 . The light incident surface 321 connects the light exit surface 322 and the bottom surface 323 , and the point light source 34 is disposed adjacent to the light incident surface 321 . The side surface 324 is connected to the light-emitting surface 322 and the bottom surface 323 , and the two opposite sides 325 and 326 are connected to the light-incoming surface 321 , the light-emitting surface 322 , the bottom surface 323 and the side surface 324 . The microstructure 42 is formed on the light incident surface 321 to reduce the area of the light mixing area by providing a light diffusing effect. The shape or configuration form of the microstructure 42 is not limited, it only needs to be able to provide a light-diffusing effect. In addition, the microstructures 44a and 44b are respectively formed on two opposite sides 325 and 326 , and the shape and design effect of the microstructures 44 (including 44a and 44b ) will be described in detail below. FIG. 5 is an enlarged view of area M of the light guide plate in FIG. 4 . As shown in FIG. 5 , in this embodiment, the microstructure 44 b includes a plurality of pillars P protruding from the side surface 326 . Each column P has a first slope S1 and a second slope S2 connected to the first slope S1, the first slope S1 is closer to the light incident surface 321 than the second slope S2, and the second slope S2 is closer to the first slope S1. It is away from the light incident surface 321 , and the length of the first slope S1 is greater than the length of the second slope S2 . In this embodiment, the range of the angle θ between the first slope S1 and the side surface 326 can be greater than or equal to 10 degrees and less than or equal to 30 degrees, and the length d of each column P projected on the side surface 326 can be is greater than or equal to 100 microns and less than or equal to 400 microns.

6 and 7 are schematic diagrams illustrating the effect of disposing the microstructure 44 on the side surfaces 325 and 326 . As shown in FIG. 6, the side beam R passing through the microstructure 42 of the light incident surface 321 has a relatively large deflection angle. When the side beam R with a large angle enters the side of the light guide plate, it is easy to refract out of the light guide plate and Create side highlights. However, as shown in FIG. 7, the side surfaces 325, 326 of the light guide plate have microstructures 44. When the side beam T with a large angle deflected by the microstructure 42 is incident on the side of the light guide plate, the side beam T encounters the microstructures. The first inclined surface S1 of the structure 44 will meet the total reflection condition and be reflected back into the light guide plate, which can effectively avoid the situation that the side beam T is refracted out of the light guide plate to form a side bright spot, and can reflect the side beam T back into the light guide plate. The light guide plate can improve the light utilization efficiency.

Although the column P in the above embodiment is a prism and the reflective surface S1 is an inclined plane, it is not limited thereto. As shown in FIG. 8, the reflective surface of the column P can be an arc surface S3 protruding from the side surfaces 325, 326. When the light beam encounters the curved surface S3, it will satisfy the total reflection condition and be reflected back into the light guide plate. Moreover, the arrangement form of the microstructures 44 on the side surfaces 325, 326 is not limited, for example, the pillars P may be arranged continuously on the side surfaces 325, 326 (FIG. 4), or arranged every two phases on the side surfaces 325, 326. Adjacent pillars P may not be connected but have an interval IN (FIG. 9). In addition, the columns P constituting the microstructure 44 can be formed by directly cutting the side of the light guide plate by cutting.

Referring to FIG. 3 again, the backlight module 30 may further include a reflective sheet (reflective sheet) 36 and an optical film set (optical film set) 38 . The reflection sheet 36 is disposed on the bottom surface 323 of the light guide plate, and the optical film group 38 is disposed on the light emitting surface 322 of the light guide plate, and is located between the liquid crystal display panel 20 and the light guide plate 32 . The optical film set 38 includes at least one of a diffusion plate, a prism plate or a brightness enhanced film (BEF). The reflection sheet 36 is used to reflect the light beam exiting the light guide plate 32 back to the light guide plate 32 so that the light beam exits from the light exit surface 322 and forms a surface light source required by the liquid crystal display panel 20 . The optical film set 38 is used to homogenize the surface light source emitted from the light-emitting surface 322 , and can be used to improve the brightness of the surface light source.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be determined by the scope of the appended claims. In addition, any embodiment or claim of the present invention need not achieve all the objects or advantages or features disclosed in the present invention. In addition, the abstract part and the title are only used to assist patent document search, and are not used to limit the scope of rights of the present invention.

Claims (13)

1. A backlight module, comprising: at least one point light source; and Light guide plate, including: light-emitting surface; a bottom surface, relative to the light-emitting surface; a light incident surface, connecting the light exit surface and the bottom surface, wherein the point light source is arranged at a position adjacent to the light incident surface; a first microstructure formed on the light incident surface; a first side, opposite to the light incident surface, and connected to the light exit surface and the bottom surface; a second side, connecting the light-emitting surface, the bottom surface, the light-incident surface and the first side; and The second microstructure is formed on the second side surface, and is used to reflect the light beam incident on the second microstructure back into the light guide plate, Wherein the second microstructure comprises a plurality of pillars protruding from the second side, and wherein each of the pillars has a first slope and a second slope connecting the first slope, the first slope closer to the light incident surface than the second slope, and the length of the first slope is greater than the length of the second slope, Wherein the angle between the first slope and the second side is greater than or equal to 10 degrees and less than or equal to 30 degrees. 2 . The backlight module according to claim 1 , wherein the length of the orthographic projection of each of the cylinders on the second side surface is greater than or equal to 100 micrometers and less than or equal to 400 micrometers. 3. The backlight module according to claim 1, wherein each of the cylinders has an arc surface, and the arc surface is used to reflect the light beam incident on the arc surface back into the light guide plate. 4. The backlight module according to claim 1, wherein the plurality of pillars are arranged continuously on the second side. 5. The backlight module according to claim 1, wherein there is an interval between every two adjacent columns. 6. The backlight module according to claim 1, wherein the point light sources are light emitting diodes. 7. A liquid crystal display, comprising: liquid crystal display panel; and A backlight module, configured on one side of the liquid crystal display panel, is used to provide the surface light source required by the liquid crystal display panel, wherein the backlight module includes: at least one point light source; and Light guide plate, including: light-emitting surface; a bottom surface, relative to the light-emitting surface; a light incident surface, connecting the light exit surface and the bottom surface, wherein the point light source is arranged at a position adjacent to the light incident surface; a first microstructure formed on the light incident surface; a first side, opposite to the light incident surface, and connected to the light exit surface and the bottom surface; a second side, connecting the light-emitting surface, the bottom surface, the light-incident surface and the first side; and The second microstructure is formed on the second side surface, and is used to reflect the light beam incident on the second microstructure back into the light guide plate, Wherein the second microstructure comprises a plurality of pillars protruding from the second side, and wherein each of the pillars has a first slope and a second slope connecting the first slope, the first slope closer to the light incident surface than the second slope, and the length of the first slope is greater than the length of the second slope, Wherein the angle between the first slope and the second side is greater than or equal to 10 degrees and less than or equal to 30 degrees. 8 . The liquid crystal display according to claim 7 , wherein the length of the orthographic projection of each column on the second side is greater than or equal to 100 micrometers and less than or equal to 400 micrometers. 9. The liquid crystal display according to claim 7, wherein each of the pillars has an arc surface, and the arc surface is used to reflect the light beam incident on the arc surface back into the light guide plate. 10. The liquid crystal display according to claim 7, wherein the plurality of pillars are arranged continuously on the second side. 11. The liquid crystal display according to claim 7, wherein there is an interval between every two adjacent columns. 12. The liquid crystal display of claim 7, wherein the point light sources are light emitting diodes. 13. The liquid crystal display according to claim 7, wherein the light guide plate is a wedge-shaped light guide plate or a flat plate type light guide plate.

Images