TWI426329B - Light guide plate, the manufacturing method thereof, and the planar illumination device comprising the light guide plate - Google Patents

Description

Light guide plate and manufacturing method thereof, and planar light source device including light guide plate

The invention relates to a planar light source device, in particular to a light guide plate used in the planar light source device and a method for manufacturing the light guide plate.

Backlight module is widely used in the field of flat panel display. Since the liquid crystal itself does not emit light, it is necessary to provide a light source with a uniform brightness and uniformity through the backlight module to display the liquid crystal, thus becoming an indispensable key component of the flat panel display. . In general, the backlight module is divided into two types: Edge Lighting and Bottom Lighting. The direct-lit backlight module places a light source such as a cold cathode fluorescent tube directly under the module, and is suitable for LCD monitors and LCD TVs that are less demanding for portability and space requirements. The edge-lit backlight module is provided with the light source on the side of the light guide plate, and is generally used for a small and medium-sized backlight module of less than 18 inches, and the light source of the side incident light source has a light weight, a thin shape, a narrow frame, and a low consumption. The characteristics of electricity. The main optical components of the edge-lit backlight module include optical elements such as a light source reflector, a light guide plate, a cymbal sheet, a reflector, and a diffusion sheet located above the cymbal. Among them, the light guide plate is a key component of the edge-lit backlight module, and its main function is to direct the light from the edge to the line of sight direction, hence the name. In order to achieve high brightness and uniform brightness, the optical design of the light guide plate is particularly important. The purpose is to use the optical design method to evenly guide the light concentrated on the edge to the entire line of sight through the light guide plate. At the office.

With the increasing demand for the screen area of the liquid crystal product and the need for thinning, how to combine the thin design that the edge-lit backlight module can achieve, and the direct-lit backlight module for the light source distribution of the large screen. It has become an important issue, and the design of the light guide plate is the key to solving this problem. The goal can be summarized in the following two points: 1) Producing a good leveling effect on a large screen without the problem of uneven brightness; 2) Producing sufficient brightness.

Therefore, actively seeking the light guide plate of the novel backlight module in the liquid crystal display can be applied to a large liquid crystal screen, and can solve the problem of uneven brightness and dark band of the screen, and generate sufficient brightness at the same time, which is an urgent solution for the industry. issue.

The present invention provides a planar light source device comprising at least a light guide plate and a light-emitting device; the light guide plate adhesively bonds the edges of the plurality of coplanar optical films to the seamless shape through the bonding process ( Seamless) One body. The above adhesive comprises a material of polymethyl methacrylate (PMMA), and the difference in refractive index between the adhesive and the optical film is less than ten percent.

The main object of the present invention is to provide a planar light source device, wherein the light guide plate is bonded by a plurality of optical films, and the optical film is bonded by a liquid glue having a refractive index similar to that of the optical film. In the subsequent development, there will be no obvious bright bands.

A secondary object of the present invention is to provide a planar light source device. Since the light guide plate is bonded by a plurality of optical films, the light is refracted and reflected from different interfaces, which results in better optical gain and uniform light. effect.

The present invention further provides a light guide plate for use in a planar light source device, wherein the light guide plate adheres the edges of the plurality of coplanar optical films to a seamless body by an adhesive process, and the adhesive includes A polymethyl methacrylate-based material, and the difference in refractive index between the adhesive and the optical film is less than ten percent.

Another object of the present invention is to provide a light guide plate which is formed by bonding a plurality of optical films, and the optical film is bonded by a liquid glue having a refractive index similar to that of the optical film, so that the subsequent development is performed. , will not show a clear bright band.

Another object of the present invention is to provide a light guide plate which is formed by bonding a plurality of optical films to refract and reflect light from different interfaces to produce a better optical gain effect and a uniform light effect.

The invention further provides a method for fabricating a light guide plate, comprising:

a) providing a plurality of coplanar optical films;

b) providing a bonding adhesive, the adhesive comprises a polymethyl methacrylate-based material, and the difference in refractive index between the adhesive and the optical film is less than ten percent;

c) applying an adhesive to the edge of the optical film;

d) Providing a bonding procedure to bond the optical film to a seamless body by means of a glue.

The main object of the present invention is to provide a method for fabricating a light guide plate, which is formed by bonding a plurality of optical films, and the optical film is bonded by a liquid glue having a refractive index similar to that of the optical film, so that the subsequent image is formed. When it does not show a distinct bright band.

Another object of the present invention is to provide a method for fabricating a light guide plate, which is formed by bonding a plurality of optical films to refract and reflect light through different interfaces, thereby producing a better optical gain effect and a uniform light effect.

The present invention discloses a planar light source device and a method for fabricating the same for the light guide plate and the light guide plate, and the optical basic principle and the related process for the light-emitting device used by the present invention have been known to those skilled in the relevant art, so the following The description will not be fully described. At the same time, the drawings in the following texts are indicative of the features related to the features of the present invention, and are not required to be completely drawn according to the actual situation.

Please refer to FIG. 1A, which is a schematic diagram of a planar light source device provided by the present invention. The planar light source device 1 mainly includes a light guide plate 10 and a light-emitting device 11. The light guide plate 10 is bonded by a plurality of coplanar optical films 101. The edge of the optical film 101 is adhered to the adhesive film 102 by a bonding process to bond the optical film 101 into a seamless shape. The adhesive 102 has a refractive index n2, and the optical film 101 has a refractive index n1, and the difference between n1 and n2 is within ten percent. Since the light 12 is emitted by the light-emitting device 10 and passes through the optical film 101 and the adhesive 102, when the difference between n2 and n1 is within ten percent, the refraction effect is not obvious, so the liquid crystal screen is displayed during subsequent development. It is not easy to produce obvious bright bands, so that the LCD screen can produce the best display effect. On the other hand, since there is still an interface at the junction of the optical film 101 and the adhesive 102, the refraction and reflection of the transmitted light at different interfaces is compared with the light guide plate composed of a single optical film of a large size. In the embodiment, the light guide plate 10 composed of a plurality of optical films 101 is provided, and the optical gain effect and the uniform light effect are relatively better.

The above-mentioned adhesive 102 contains a polymethyl methacrylate system (i.e., an acrylic system) having a composition similar to that of the optical film 101, and thus has a refractive index similar to that of the optical film 101. The adhesive 102 may be made of homogenized polymethyl methacrylate, and may be completely transparent; or may be microparticles in which polymethyl methacrylate microparticles or enamel materials are added, and may be translucent. The bonding process can be high-frequency welding or thermal fusion. However, if the heat-sealing method is used as the bonding process, the edge of the optical film 101 may be directly melted without using the adhesive 102, and then welded.

Please refer to Figures 1A and 1B. The planar light source device 1 can be applied to the edge light type backlight module or the direct type backlight module, and the light emitting device 11 (light source) can be disposed on the side of the light guide plate 10 according to different types of backlight groups. (as in Figure 1A) or the bottom (as in Figure 1B). The type of the light-emitting device 11 may be an LED array or a cold cathode fluorescent lamp (CCFL); and the shape of the optical film 101 may be a flat plate having a uniform thickness (such as FIG. 1A) having a tapered thickness. A wedge plate (as in Figure 1C) or a shape design with other structures.

In addition to the planar light source device of the first preferred embodiment, the present invention further provides a second preferred embodiment, which is a light guide plate for use in a planar light source device. Referring to FIGS. 1A to 1C, the light guide plate 10 of the second preferred embodiment is an edge of a plurality of coplanar optical films 101 arranged by a bonding adhesive 102. The adhesive is adhered to a seamless body, and the adhesive 102 comprises a polymethyl methacrylate-based material, and the optical refractive index difference between the adhesive and the optical film is less than ten percent. The characteristics of the main components of the light guide plate 10, such as the material of the adhesive 102, the bonding process, and the preferred configuration of the optical film 101 are the same as those described in the foregoing first preferred embodiment.

Referring to FIG. 2, the present invention further provides a third preferred embodiment, which is a method for fabricating a light guide plate, wherein the component number of the light guide plate used is as described in the first preferred embodiment, please refer to FIG. 1A. To the 1C chart. The manufacturing method 2 of the light guide plate comprises the following steps:

Step 21: providing a plurality of coplanar arrays of optical films 101.

Step 22: Providing an adhesive 102, the adhesive 102 comprises a polymethyl methacrylate-based material, and the difference in refractive index between the adhesive 102 and the optical film 101 is less than ten percent.

Step 23: Apply the adhesive 102 to the periphery of the optical film 101.

Step 24: Providing a bonding process, the optical film 101 is bonded to the seamless body by the adhesive 102.

The main component features of the light guide plate 1 produced according to the second method of manufacturing the light guide plate, including the preferred material of the adhesive 102, the detailed bonding procedure, and the preferred material of the optical film 101 are the same as the first The details are not described here.

The present invention has been clearly described by the various embodiments and the associated drawings, and may be implemented by those skilled in the art. However, the various embodiments of the present invention are intended to be illustrative and not restrictive, that is, the variations and modifications of the various embodiments described above are all in accordance with the present invention. Covered. Accordingly, the invention is defined by the scope of the appended claims.

1. . . Planar light source equipment

10. . . Light guide

11. . . Illuminating device

12. . . Light

101. . . Optical diaphragm

102. . . Adhesive

21, 22, 23, 24. . . step

FIG. 1A is a schematic diagram of a planar light source device according to a first preferred embodiment of the present invention.

FIG. 1B is another schematic diagram of a planar light source device according to a first preferred embodiment of the present invention.

FIG. 1C is still another schematic view of the first preferred embodiment of the present invention.

Figure 2 is a flow chart of a second preferred embodiment of the present invention.

1. . . Planar light source equipment

10. . . Light guide

11. . . Illuminating device

101. . . Optical diaphragm

102. . . Adhesive

Claims (10)

A planar light source device comprising at least one light guide plate and a light-emitting device, wherein the light guide plate adhesively bonds the edges of the plurality of coplanar optical films to a seamless body through a bonding process. The adhesive comprises a polymethyl methacrylate-based material, and the optical refractive index difference between the adhesive and the optical film is less than ten percent. The planar light source device of claim 1, wherein the light emitting device is selected from the group consisting of an LED array and a plurality of cold cathode fluorescent lamps (CCFLs). A planar light source device according to claim 1, wherein each of the optical films has a uniform thickness. A planar light source device according to claim 1, wherein each of the optical films has a tapered thickness. A light guide plate can be used for a planar light source device, wherein the light guide plate adhesively bonds the edges of the plurality of coplanar optical films to a seamless body through a bonding process, the adhesive glue A polymethyl methacrylate-based material is included, and the optical refractive index difference between the adhesive and the optical film is less than ten percent. A light guide plate according to item 5 of the patent application, wherein the adhesive comprises fine particles of a polymethyl methacrylate-based material. A light guide plate according to claim 5, wherein the adhesive comprises fine particles of a bismuth material. A method for fabricating a light guide plate, comprising: providing a plurality of coplanar arrays of optical films; providing an adhesive, the adhesive comprising a polymethyl methacrylate-based material, and the optical refraction of the adhesive and the optical film The difference in rate is less than 10%; the adhesive is applied to the edges of the optical films; and a bonding process is provided, and the optical films are bonded to the seamless body by the adhesive. According to the method for manufacturing a light guide plate according to Item 8 of the patent application, wherein the bonding procedure is high frequency Welding. A method of fabricating a light guide plate according to claim 8 wherein the bonding process is heat fusion.