CN1749783A - Microstructure of light guide plate - Google Patents

Abstract

The invention discloses a microstructure of a light guide plate, namely a light guide plate of a backlight module for a liquid crystal display, wherein a light source is arranged on the side surface of the light guide plate, the microstructure is arranged on the bottom surface of the light guide plate, is a triangular cone-shaped structure protruding outwards from the bottom surface of the light guide plate and comprises a non-light reflecting surface and two light reflecting surfaces, the non-light reflecting surface is vertical to the bottom surface of the light guide plate and faces the light source and is closer to the light source, the two light reflecting surfaces are inclined to the bottom surface of the light guide plate and face a light outlet surface of the light guide plate and are far away from the light source, and light is rebounded to the upper part by virtue of the light reflecting surfaces to increase the luminance of the.

Description

Microstructure of light guide plate

technical field

The invention relates to a microstructure of a light guide plate.

Background technique

Please refer to FIG. 1, which is a schematic diagram of a microstructure 2 of a conventional light guide plate 1, which produces a microstructure 2 with a rough surface on the bottom surface 12 of a smooth light guide plate 1 by etching, and an incident light 50 enters the surface of the microstructure 2. That is, scattered reflected light rays 51 or refracted light rays 52 are produced. When the angle of incidence of the scattered light 51 incident on the light-emitting surface 11 of the light guide plate 1 is less than the critical angle, it exits the light-emitting surface 11 of the light guide plate 1; inside and pass on.

FIG. 2 explains the coordinates of FIG. 3 a . FIG. 3 a is a radar diagram of light intensity emitted from the light emitting surface 11 of the conventional light guide plate 1 . The abscissa represents the horizontal angle (Harizontal angle, HA), and the movement of the angle is from the normal direction 13 of the light-emitting surface 11 to the direction 14 perpendicular to the light source 4; the ordinate represents the vertical angle (Vertical angle, VA), and the movement of the angle is from the light-emitting The normal direction 13 of the surface 11 turns to a direction 15 parallel to the light source 4 . In Fig. 3a, each closed curve represents a light intensity value, which is defined as the luminous flux per unit solid angle. There are 10 closed curves in this figure, representing 10 levels of light intensity. It can be seen from FIG. 3a that the light intensity distribution of light emitted from the conventional light guide plate 1 is approximately Lambertian distribution, that is, a circular closed curve is formed in FIG. 3a, and the light intensity distribution presents a cosine function. The light intensity is converted into a luminance value, that is, the luminance is equivalent in all directions.

Please refer to FIG. 3 b , which is a perspective view of the light output intensity of the light output surface 11 of the conventional light guide plate 1 . The light intensity distribution is approximately spherical, that is, close to the Lamberson distribution. This figure can be used to observe the changes of the light intensity at various angles or directions.

In addition, the microstructures disclosed in U.S. Patent No. 6746129 and No. 6894740 are all diamond-shaped cones, and the two adjacent slopes before the rhombic cone face the light source, and the incident light is continuously reflected on the two adjacent slopes to emit light. Among them, No. 6746129 The microstructure is arranged on the light guide plate with a point light source, while No. 6894740 is used with a linear light source. This case also discloses the design of adding a point light source at both ends of the line light source.

On the whole, the structure of the rhombic cone is relatively complicated, and in fact, among the four adjacent slopes, the two adjacent slopes close to the light source have little effect.

Contents of the invention

The purpose of the present invention is to provide a microstructure of the light guide plate, which can enhance the emission of light to the light-emitting surface of the light guide plate, so as to increase the luminance of the light guide plate.

In order to achieve the above object, the technical solution of the present invention is: a microstructure of a light guide plate, the light guide plate includes an upper surface and a side surface, the side of the light guide plate is provided with a light source, and the upper surface of the light guide plate is a light-emitting surface, and the opposite surface of the light-emitting surface is the bottom surface; the microstructure is arranged on the bottom surface of the light guide plate, and is in the shape of a triangular pyramid protruding from the bottom surface of the light guide plate. The triangle cone includes a non-light reflection surface and two light reflection surfaces, wherein the non-light reflection surface is perpendicular to The bottom surface of the light plate faces and is closer to the light source, while the light reflection surface is inclined to the bottom surface of the light guide plate, faces the light-emitting surface of the light guide plate, and is farther away from the light source.

The edge where the two light reflecting surfaces intersect is the direction on the light guide plate, and the above-mentioned directions are all parallel to the direction in which the light source emits light.

The edge where the two light reflecting surfaces intersect is the direction on the light guide plate, and the above-mentioned directions are not completely parallel to the direction of the light emitted by the light source, but tend to be parallel to the direction of the light emitted by the light source.

The arrangement of the microstructures on the light guide plate can be a regular arrangement or a random number arrangement.

After adopting the above solution, due to the microstructure of the bottom surface of the light guide plate of the present invention, its shape is a triangular pyramid structure protruding outward from the bottom surface of the light guide plate, which bounces the light upwards by means of the light reflection surface, which can effectively improve the light to the light output surface of the light guide plate Injection increases the luminance of the light guide plate, thereby changing the arrangement of microstructures to improve the uniformity of the luminance of the light guide plate; and its structure is simple and the light guide direction is clear, easy to simulate and design layout in advance, and easier to control cost and quality.

Description of drawings

1 is a schematic diagram of a conventional microstructure of a light guide plate;

FIG. 2 is a schematic diagram of light emitting from the light emitting surface of a conventional light guide plate (also illustrating the coordinate axes in FIG. 3 );

Fig. 3a is a radar diagram of the light output intensity of the light output surface of the conventional light guide plate;

Fig. 3b is a three-dimensional view of the light output intensity of the light output surface of the conventional light guide plate;

Figure 4a is a side view of the application of the microstructure of the example of the present invention to a light guide plate;

Fig. 4b is a bottom view of the microstructure applied to the light guide plate of the example of the present invention (also the first embodiment of the microstructure of the example of the present invention distributed on the light guide plate);

Figure 5a is a schematic top view of the microstructure of the example of the present invention;

Figure 5b is a schematic bottom view of the microstructure of the example of the present invention;

Figure 5c is a schematic top view of the microstructure of the example of the present invention;

Figure 5d is a schematic side view of the microstructure of the example of the present invention;

Fig. 6a is a three-dimensional schematic diagram of the transmission behavior of light in the microstructure of the example of the present invention;

Fig. 6b is a top view schematic diagram of the transmission behavior of light in the microstructure of the example of the present invention;

Fig. 6c is a schematic side view of the transmission behavior of light in the microstructure of the example of the present invention;

Figure 7 is a radar diagram of the light intensity distribution after the light enters the microstructure of the example of the present invention with angles β and θ as parameters;

Fig. 8 is a three-dimensional view of the light output intensity after the light enters the microstructure of the example of the present invention with β=50 degrees and θ=30 degrees as parameters;

Fig. 9 is a three-dimensional view of the light output intensity after the light enters the microstructure of the example of the present invention with β=40 degrees and θ=10 degrees as parameters;

Fig. 10 is a three-dimensional view of the light output intensity after the light enters the microstructure of the example of the present invention with β=60 degrees and θ=20 degrees as parameters;

Fig. 11 is a diagram of the second embodiment of the microstructure distributed in the light guide plate of the present invention;

Fig. 12 is a diagram of a third embodiment of the microstructure distributed in the light guide plate of the present invention;

FIG. 13 is a diagram of a fourth embodiment of the present invention in which microstructures are distributed on a light guide plate.

Explanation of main component symbols

1, 1A, 1B, 1C, 1D light guide plate 11, 11A light exit surface

12, 12A Bottom surface 13 Normal direction of light-emitting surface

14 Direction perpendicular to light source 15 Direction parallel to light source

2 Microstructure 3 Reflector

4 Linear light source 5 Light

50 Incident Rays 51 Reflected Rays

52 Refracted Light 6 Microstructure

601 Non-light reflective surface 602, 603 Light reflective surface

611, 612 bottom edge 613 edge

β The angle between the light reflecting surface and the bottom edge

θ The angle between the edge of the light reflecting surface and the bottom surface

7 points to

Detailed ways

The light guide plate of the invention can be used in a backlight module of a liquid crystal display. The side is provided with a light source, the upper surface is a light emitting surface, and the opposite surface of the light emitting surface is a bottom surface.

Please refer to FIG. 4 a , which is a schematic diagram of applying the microstructure 6 of the example of the present invention to the light guide plate 1A. The light guide plate 1A includes a plurality of microstructures 6 arranged on the bottom surface 12A of the light guide plate 1A, and its shape is a triangular pyramid structure protruding outward from the bottom surface 12A of the light guide plate 1A. When the light emitting surface 11A is used, the luminance of the light guide plate 1A can be improved.

4b is a diagram of the first embodiment of the microstructures 6 distributed in the light guide plate 1A according to the example of the present invention. The arrangement of the microstructures 6 is regular, and the directions 7 of all the microstructures 6 are completely parallel to the light emitted by the linear light source 4. The light emitted by the linear light source 4 enters the light guide plate 1A to generate surface-shaped light with high uniform brightness.

Please refer to FIGS. 5 a - 5 d , which are schematic diagrams of the structure of the microstructure 6 of the example of the present invention, and are respectively a top view, a bottom view, a top view and a side view. The microstructure 6 is a triangular pyramid structure, including a non-light reflective surface 601 and two light reflective surfaces 602, 603, the non-light reflective surface 601 is perpendicular to the bottom surface 12A of the light guide plate 1A, and it faces and is closer to the light source 4 The two light reflecting surfaces 602 and 603 are inclined to the bottom surface 12A of the light guide plate 1A, and face the light emitting surface 11A of the light guide plate 1A and are far away from the light source 4 . Since the light reflecting surfaces 602 and 603 have the ability to change the light traveling in the light guide plate 1A, when the light enters the microstructure 6, the light reflecting surfaces 602 and 603 reflect the light upwards, thereby increasing the brightness of the light guide plate 1A.

Please refer to Fig. 5c, 5d, wherein the angle between the bottom edges 611, 612 between the two light reflecting surfaces 602, 603 and the bottom surface 12A of the light guide plate 1A is β, and the edge 613 between the two light reflecting surfaces 602, 603 is connected to The angle formed by the bottom surface 12A of the light guide plate 1A is θ. These two angles β and θ can change the inclinations of the light reflecting surfaces 602 and 603 , and most affect the intensity distribution of light directed upward.

Wherein, the edge 613 connecting the two light reflecting surfaces 602 and 603 is the direction 7 of the microstructure 6 (see FIG. 4b ).

Please refer to each figure in FIG. 6 , which is a schematic view of the light transmission when the light 5 enters the microstructure 6 . After the light 5 enters the light reflecting surface 602, it is reflected to another light reflecting surface 603, and is reflected by the light reflecting surface 603 to be emitted upward. Similarly, after the light 5 enters the light reflecting surface 603 , it passes through the light reflecting surface 602 to the top. The angle θ affects the inclination of the up-down direction (Z-axis direction) of the light reflecting surfaces 602, 603, and affects the change of light intensity on the HA; the angle β affects the inclination of the left-right direction (Y-axis direction) of the light reflection surfaces 602, 603, and affects the light intensity. Changes in VA.

Please refer to FIG. 7 , which is a radar diagram of light intensity distribution after light enters the microstructure 6 with angles β and θ as parameters. The inventors used the example of the present invention as a design model to find out the most appropriate angles β and θ to obtain a high light intensity distribution on the light-emitting surface 11A of the light guide plate 1A. Among the design parameters, the angle β is 30 degrees, 40 degrees, 50 degrees, and 60 degrees respectively, and the angle θ is 10 degrees, 20 degrees, 30 degrees, and 40 degrees respectively. The inventor simulates the above parameters with ASAP optical software, and obtains the angle When β is 50 degrees and 60 degrees, and the angle θ is 30 degrees, there is a high light intensity distribution, as can be seen in Figure 8. The light is concentrated and emitted on the normal direction 13, that is, on the normal direction 13 (VA=0 degree, HA = 0 degrees) the light intensity value is the highest. When the angle θ=10 degrees, the light is concentrated at VA=60 degrees, as shown in FIG. 9 . When the angle θ=20 degrees, the light is concentrated in the area of VA=60 degrees, HA=±30-40 degrees, and the distribution of the light intensity has a bifurcation, as shown in Figure 10. It can be seen from this that the change of the angles β and θ affects the light intensity distribution of the light-emitting surface 11A of the light guide plate 1A.

As for the arrangement of the microstructures 6 in the light guide plate 1A of the example of the present invention, please refer to FIG. The direction 7 of the structure 6 is parallel to the light emitted by the linear light source 4 . The light emitted by the linear light source 4 enters the light guide plate 1A to produce a surface light source with high uniformity and brightness.

Please refer to FIG. 11 , which is a second embodiment of the microstructure 6 distributed in the light guide plate 1B of the present invention. The microstructures 6 are arranged regularly, and the points 7 of all the microstructures 6 are not completely parallel to the light emitted by the linear light source 4 , but overall, the points 7 of the microstructures 6 tend to be parallel to the light. The light emitted by the linear light source 4 enters the light guide plate 1B to generate a surface light source with high uniformity and brightness.

Please refer to FIG. 12 , which is a third embodiment of the microstructures 6 distributed in the light guide plate 1C according to the present invention. The microstructures 6 are arranged in random numbers, and the direction 7 of the microstructures 6 is parallel to the light emitted by the linear light source 4 . The light emitted by the linear light source 4 enters the light guide plate 1C to generate a surface light source with high uniformity and brightness.

Please refer to FIG. 13 , which is a fourth embodiment of the microstructures 6 distributed in the light guide plate 1D according to the present invention. The microstructures 6 are arranged in a random number arrangement, and the points 7 of all the microstructures 6 are not completely parallel to the light emitted by the linear light source 4 , but overall, the points 7 of the microstructures 6 tend to be parallel to the light. The light emitted by the linear light source 4 enters the light guide plate 1D to generate a surface light source with high uniformity and brightness.

Except that the above four embodiments use linear light sources, such as cold cathode tubes, as light sources, multiple point light sources such as light emitting diodes can also be used as light sources, and their microstructure arrangement and orientation are roughly the same as those of the foregoing embodiments.

Claims (5)

1. A microstructure of a light guide plate, the light guide plate includes a top and a side, the side of the light guide plate is provided with a light source, and the top of the light guide plate is a light-emitting surface, and the opposite surface of the light-emitting surface is a bottom surface, it is characterized in that: the microstructure is designed On the bottom surface of the light guide plate, and protruding outward from the bottom surface of the light guide plate, the triangular cone includes a non-light reflective surface and two light reflective surfaces, wherein the non-light reflective surface is perpendicular to the bottom surface of the light guide plate, and faces and It is closer to the light source, and the light reflection surface is inclined to the bottom surface of the light guide plate, faces the light emitting surface of the light guide plate, and is farther away from the light source. 2. The microstructure of the light guide plate according to claim 1, wherein the edge where the two light reflecting surfaces intersect is the direction on the light guide plate, and the above directions are all parallel to the direction of the light emitted by the light source. 3. The microstructure of the light guide plate according to claim 1, characterized in that: the edge where the two light reflecting surfaces intersect is the direction on the light guide plate, and none of the aforementioned directions is completely parallel to the direction in which the light source emits light. But it tends to be parallel to the direction of light emitted by the light source. 4. The microstructure of the light guide plate according to claim 1, characterized in that: the arrangement of the microstructures on the light guide plate is a regular arrangement. 5. The microstructure of the light guide plate according to claim 1, characterized in that: the arrangement of the microstructures on the light guide plate is a random number arrangement.

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