TWI332089B - Light guide plate and method for making the same - Google Patents

Description

1332089 - Aug. 04, 099, Amendment and Replacement Page 6 Description of the Invention: [Technical Field] [0001] The present invention relates to a light guide plate and a method of fabricating the same, and more particularly to a light guide plate for a side-mounted backlight module And its preparation method. [Prior Art] [0002] Since the liquid crystal of the liquid crystal display panel itself has no illuminating property, in order to achieve the display effect, it is necessary to provide a liquid crystal display panel with a light source device, such as a backlight module, which functions to supply brightness to the liquid crystal display panel and A uniform surface light source.

Referring to FIG. 1, a side-mounted backlight module 10 using a conventional light guide plate includes a light guide plate 11, a light source 13, a reflection plate 15, a diffusion sheet 17, and a prism sheet 19. The light guide plate 11 includes a light exit surface 112, a bottom surface 114 opposite to the light exit surface 112, and a light incident surface 116 connecting the light exit surface 112 and the bottom surface 114. The bottom surface 114 of the light guide plate 11 is formed with a plurality of hemispherical convex microstructures 118, and the surface of the microstructure 118 is a mirror surface. The light source 13 is disposed on the light incident surface 116 and can emit light to the light guide plate 11. The reflector 15 is disposed below the bottom surface 114 of the light guide plate 11. The diffusion sheet 17 and the prism sheet 19 are sequentially disposed on the upper side of the light-emitting surface 112 of the light guide plate 11. The function of the light guide plate 11 is to destroy the total reflection condition of the light by the action of the plurality of micro-structures 118 to guide the light transmission direction so that the light is uniformly emitted from the light-emitting surface 11 2 of the light guide plate 11. The reflector 15 can reflect the light emitted from the bottom surface 114 of the light guide plate 11 into the light guide plate 11 to improve the utilization of light. The diffusion sheet 17 and the prism sheet 19 allow the light emitted from the light guide plate 11 to have better uniformity and brightness, thereby improving the brightness and uniformity of the liquid crystal display panel. [0004] However, since the surface of the microstructure 118 of the light guide plate 11 is a mirror surface, the light reaches 096109280. Form No. A0101 Page 3 / 18 pages 0993278706-0 1332089 099 August 04B Correction of the replacement page microstructure 118 occurs when specular reflection occurs The specular reflection can make the light emitted from the light guide plate 11 have better viewing angle convergence, but the light uniformity is poor.

[0005] Referring to FIG. 2, in order to improve the shortcoming of the uniformity of the light emitted from the light guide plate 11, the prior art further provides a light guide plate 21. The light guide plate 21 is similar to the above-described light guide plate 11, and the difference is that the surface of the microstructure 218 is set to a rough surface. Thus, the light reaches the rough surface and diffusely reflects, so that the light emitted from the light exit surface 212 of the light guide plate 21 has a good uniformity. However, the diffuse reflection also causes the light emitted from the light exiting surface 212 of the light guide plate 21 to have a large exit angle, and the viewing angle is less abrupt, resulting in a lower intensity of light emitted from the light exiting surface 21 of the light guide plate 21. [Explanation] [0006] In view of the above circumstances, it is necessary to provide a light guide plate having both good viewing angle convergence and light emission uniformity and a preparation method thereof.

[0007] A light guide plate includes a light emitting surface, a bottom surface opposite to the light emitting surface, and at least one light incident surface connecting the light emitting surface and the bottom surface, the bottom surface forming a plurality of microstructures, each of the microstructures including a mirror surface And a rough face that reflects specularly the light projected onto it, the rough face diffusing the light projected onto it. [0008] A light guide plate preparation method, comprising the steps of: heating a transparent resin to form a molten light guide plate material; injecting a molten light guide plate material into a mold cavity of an injection molding die, at least one inner wall of the mold cavity is formed with a plurality of Microstructure, and each microstructure comprises a mirror surface and a rough surface; solidifying the molten light guide plate material in the mold cavity to form a light guide plate, one surface of the light guide plate forming a plurality of microstructures, each microstructure including a mirror surface 096109280 Form No. A0101 Page 4 of 18 0993278706-0 On August 4, 099, Shuttle is replacing page 1332089 with a rough face. [0009] A method for preparing a light guide plate, comprising the steps of: providing a transparent plastic substrate and a hot press molding die, the hot press molding die comprising a template

Forming a plurality of microstructures on one surface of the template, and each of the microstructures includes a mirror surface and a rough surface; heating the transparent plastic substrate to soften the surface; the surface of the template formed with the plurality of microstructures is in contact with one surface of the transparent plastic substrate Applying a certain pressure to the plastic substrate by the template, so that the surface of the transparent plastic substrate forms a plurality of microstructures, each of which includes a mirror surface and a rough surface; and the transparent plastic substrate is used to form a light guide plate. [0010] Compared with the prior art, the light guide plate has the following advantages: the bottom surface of the light guide plate forms a plurality of microstructures, each of the microstructures includes a mirror surface and a rough surface, and the mirror surface makes the light passing through the light guide plate have V-determination The viewing angle converges, and the rough surface makes the light passing through the light guide plate have better uniformity, thereby effectively improving the viewing angle convergence and the light uniformity of the entire light guide plate. [Embodiment] The light guide plate and the preparation method of the present invention will be further described in detail below with reference to the accompanying drawings and the embodiments. [0012] Referring to FIG. 3 and FIG. 4 together, a preferred embodiment of the present invention provides a light guide plate 30. The light guide plate 30 has a square shape and includes a light exit surface 312, a bottom surface 314 opposite to the light exit surface 31 2, and four light incident surfaces 316 connecting the light exit surface 312 and the bottom surface 314. The bottom surface 314 is formed with a plurality of microstructures 318 having the same shape, and the microstructures 318 are prismatic projections. The plurality of microstructures 318 are arranged in an array on the bottom surface 314, and the ends of each of the microstructures 318 form a rough surface having a rough surface, and the sides thereof form a mirror surface having a smooth surface. The mirror face can specularly reflect the light projected onto it, and the rough face can illuminate the light on the 096109280 form number A0101, which can be used to correct the replacement page on August 4, 099. Diffuse reflection. 5。 The roughness of the surface of the rough surface is 30% to 70%, and the roughness of the rough surface is greater than or equal to 0.2. It can be understood that the area of the mirror surface can also be 30% to 70% of the sum of the areas of the rough surface and the mirror surface. [0013] In addition, in order to make the light guide plate 30 have better optical effect and lighter weight, the light guide plate 30 of the embodiment can be made of a light transparent transparent resin material, such as acrylic resin, polycarbonate, and poly. Vinyl resin, etc.

[0014] Since the bottom surface 314 of the light guide plate 30 is formed with a plurality of microstructures 318, each of the microstructures 318 is formed with a mirror surface and a rough surface, and the mirror surface of the light projected onto the mirror surface is reflected by the mirror surface. The light of the light plate 3 has a good viewing angle convergence; the diffuse reflection of the light projected onto the rough surface by the rough surface 'the rough surface makes the light passing through the light guide plate 3 have better uniformity', thereby effectively improving the entire light guide plate 30 view convergence and light uniformity.

[0015] It will be understood that the light guide plate of the present invention may also be a pentagon, a hexagon or the like, or even a wedge shape. Moreover, the microstructure formed on the bottom surface may also be randomly arranged. [0016] Please refer to FIG. 5, a preferred embodiment of the present invention provides a light guide plate 5A. The light guide plate 50 is similar to the light guide plate 30 of the preferred embodiment, except that the end portion of the microstructure 518 of the light guide plate 50 forms a mirror surface having a smooth surface, and the side surface thereof forms a rough surface of the surface rough sugar. [0017] Referring to FIG. 6 and FIG. 7, a preferred embodiment 3 of the present invention provides a light guide plate 60. The light guide plate 60 is similar to the light guide plate 3 of the preferred embodiment, 096109280 Form No. A0101 Page 6 / Total 18 pages 0993278706-0 1332089 [0018] The revised replacement page of August 4, 099 is different in that: The microstructure 618 of the bottom surface 614 of the light guide plate 60 is a groove which is in the shape of an inverted prism and the bottom of the groove forms a rough surface portion. Referring to FIG. 8, a preferred embodiment 4 of the present invention provides a light guide plate 7A. The light guide plate 70 is similar to the light guide plate 3A of the first embodiment except that the microstructure 718 of the light guide plate 70 is in the shape of a truncated cone, and the end portion of the microstructure 718 forms a rough surface, and the side surface forms a mirror surface. It will be understood that the rough surface and the mirror surface may also be formed on the sides and ends of the microstructure, respectively. φ [0019] Please refer to FIG. 9. A preferred embodiment 5 of the present invention provides a light guide plate 8A. The light guide plate 80 is similar to the light guide plate 20 of the first embodiment except that the light guide plate 80 has a wedge shape. Thus, the light guide plate 80 has only a light-incident surface. [0020] It can be understood that the micro-structure formed on the bottom surface of the light guide plate may be a protrusion or a groove, and the shape may be other shapes such as an elongated shape or a hemispherical shape, in addition to a prismatic shape and a truncated cone shape. Moreover, the shape and size of the plurality of microstructures may be the same or different. The formation position of the mirror face and the rough face on the microstructure can be changed. In addition, the mirror surface and the wheel surface on the surface of the microstructure may be interlaced, and the partition structure may be thinner. In any case, the surface of the microstructure may be formed with a mirror surface and a rough surface. In this way, the mirror surface makes the light passing through the light guide plate have a better viewing angle convergence, and the rough surface makes the light passing through the light guide plate have better uniformity, thereby effectively improving the viewing angle convergence and the light uniformity of the entire light guide plate. [0021] A method of preparing the above-described light guide plate 30 is prepared by using an injection molding die. [0022] Please refer to FIG. 10 'The injection molding die includes a first die 3〇丨 and a _ 096109280 Form No. 1010101 Page 7 / Total 18 Page 0993278706-0 1332089 _ 099 0·August 04· The page mold 303 is replaced. The first mold 301 has a molding groove 3011, and the molding groove 3011 can cooperate with the second mold 303 to form a mold cavity. The second mold 3〇3 is formed with a plurality of groove-like microstructures corresponding to the molding grooves 3011 of the first mold 301, and the shape of each of the microstructures corresponds to the shape of the microstructure 318 of the bottom surface 314 of the light guide plate 30. And each of the microstructures includes a mirror surface and a rough surface, wherein the mirror surface is located on the sidewall of the groove, and the rough surface structure is located at the groove bottom of the groove, and the two are respectively used to form the mirror surface and the roughness of the microstructure 318 of the light guide plate 30. Face.

[0023] When the second mold 303 cooperates with the molding groove 3011 of the first mold 301 to form a mold cavity, the second mold 303 is formed with a partial region of the plurality of microstructures as an inner wall of the mold cavity, that is, the inner wall has a plurality of A groove-like microstructure, and each microstructure includes a mirror face and a rough face. [0024] During the preparation process, the transparent resin material may be heated to form a molten light guide plate material, and then the molten light guide plate material is injected into the mold cavity of the injection molding die, and then the molten light guide plate material is solidified in the mold cavity. A light guide plate is formed, one of the surfaces of the light guide plate forming a plurality of microstructures, each of the microstructures including a mirror surface and a rough surface. [0025] In order to make the injection molding die easier in disassembly and assembly, the second die 303 can be designed in a combined form, that is, the second die 303 can be composed of a base 3031, a first die 3035, and a second die. 3037 is a combination. A mounting groove 3033 is defined in the base body 3031. The first mold core 3035 and the second mold core 3037 are sequentially disposed inside the mounting groove 3033. The surface of the first mold core 3035 is formed with a plurality of rough surface areas. A plurality of rib-shaped through holes are formed in the second mold core 3037, and the side faces of the through holes are mirror surfaces. Thus, when the first mold core 3035 is engaged with the second mold core 3037, the rough surface area of the first mold core 3035 is respectively 096109280 Form No. 1010101 Page 8 of 18 0993278706-0 1332089

[0028] [0028]

(4) August of the year Located at the opening of the through hole of the third 〇 彳 仁 仁 以 以 以 以 以 以 以 以 以 以 以 以 以 。 。 。 。 。 。 。 。 。 。 。 。 。 。 In addition, the rough surface area of the first mold core 3〇35 can be obtained by mechanical processing, electric discharge machining, sandblasting or chemical etching, and the through hole side of the second mold core 3〇37 can be machined. It can be understood that in the above injection molding die, the groove of the injection molding die can be converted into other structures such as protrusions according to the change of the micro-convex structure of the light guide plate. It will be appreciated that the plurality of microstructures may also be disposed at the bottom of the groove of the forming groove of the first mold. A method of preparing the above-mentioned light guide plate 6 is prepared by a hot press molding die. . . . , referring to FIG. 11 , the hot press forming mold & template - the surface of one of the templates 4 is formed with a plurality of prismatic protrusions 405, the shape of each microstructure 405 and the above guide The microstructure of the bottom surface 614 of the light plate 6 is 618, and the mouth gauge is used to refine the face. Among them, the rough surface is formed at the end of the microstructure 4 () 5, the mirror surface is formed on the microstructure 405, and the rough sugar surface and the mirror surface of the material 3 of the sapphire 3 () are used. Then, the transparent plastic substrate is heated and softened. The heating temperature is above the transition temperature of the corresponding (4) slope. Forming a surface of the surface plate transparent plate 610 of the template 4G0 with a plurality of microstructures 4Q5 and applying a constant pressure to the transparent plastic knee substrate by the mold to form a plurality of microstructures on the surface of the transparent (four) substrate 6U). The structure includes a mirror face and a thick key face. The transparent plastic substrate 610 produces a light guide plate 60. 7 096109280 Form No. A0I01 % 9 ]8 ^ 0993278706-0 1332089 On August 4, 099, the shuttle is replacing the page [0029] It can be understood that in the above hot press molding die, according to the change of the microprojection structure of the light guide plate, heat The microstructure of the press forming mold can also be set to other structures such as grooves. [0030] In summary, the present invention complies with the requirements of the invention patent, and submits a patent application according to law. However, the above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art of the present invention should be included in the following claims. [Simple description of the map]

[0031] FIG. 1 is a schematic structural view of a backlight module using a conventional light guide plate. 2 is a schematic cross-sectional view of another light guide plate of the prior art. 3 is a schematic perspective view of a light guide plate according to a preferred embodiment of the present invention. 4 is a cross-sectional view of the light guide plate of FIG. 3 taken along line IV-IV. 5 is a schematic perspective view of a light guide plate according to a second embodiment of the present invention. 6 is a schematic perspective view of a light guide plate according to a third embodiment of the present invention.

7 is a schematic cross-sectional view of the light guide plate of FIG. 6 taken along line VII-VII. 8 is a schematic perspective view of a light guide plate according to a fourth embodiment of the present invention. 9 is a schematic perspective view of a light guide plate according to a fifth embodiment of the present invention. [0040] FIG. 10 is a schematic view showing the preparation of the light guide plate shown in FIG. 3 by using an injection molding die. [0041] FIG. 11 is a schematic view showing the preparation of the light guide plate shown in FIG. 6 by a hot press molding die. [Description of Main Component Symbols] [0042] (Invention) 096109280 Form No. A0101 Page 10/Total 18 Pages 0993278706-0 1332089 [0044] [0046] [0049] [0049] [0049] Corrected replacement page on August 4, 2008

[0055] [0055] [0055] [0055]

[0058] [0060] [0060] [0061] Light guide plate: 30 ' 50 ' 60 ' 70, 80 light surface: 312 bottom surface: 314, 614 light surface: 316 microstructure: 318, 518 , 618, 718 First mold: 301 Molding groove: 3011 Second mold: 303 Base: 3031 Inlay groove: 3033 First mold: 3035 Second mold: 3037 Template: 400 Microstructure: 405 Transparent plastic substrate: 610 ( Conventional) Backlight module: 10 Light guide plate: 11, 21 Light exit surface: 112, 212 096109280 Form No. A0101 Page 11/Total 18 Page 0993278706-0 1332089 [0062] Bottom surface: 114 [0063] Glowing surface: 11 6 [0064] Microstructure: 118, 218 [0065] Light source: 1 3 [0066] Reflector: 15 [0067] Diffusion sheet: 17 [0068] Prism sheet: 19 096109280 Form number A0101 Page 12 of 18 Page 099 August 04 revised replacement page 0993278706-0

Claims (1)

Modified on August 4, 099 1332089 VII. Patent Application Range: 1. A method for preparing a light guide plate, comprising the steps of: heating a transparent resin to form a molten light guide plate material; The molten light guide plate material is injected into a mold cavity of the injection molding die, the injection molding die includes a first mold and a second mold, the first mold has a molding groove, and the second mold is composed of a base body The first mold core and the second mold core are combined, and the base body defines a mosaic groove matched with the molding groove of the first mold, and the first mold core and the second mold core are sequentially disposed inside the mosaic groove. The surface of the first mold core is formed with a plurality of rough surface regions, the second mold core is formed with a plurality of through holes, the side surface of the through hole is a mirror surface, and the first mold core is matched with the second mold core and the rough surface area is made Located at the opening of the through hole respectively; 'curing the light guide plate material in the mold cavity to form a light guide plate, one of the surfaces of the light guide plate forming a plurality of protrusions, each protrusion including a mirror surface and a rough surface. 2. The method of preparing a light guide plate according to claim 1, wherein the protrusion is one of a prismatic protrusion and a truncated cone, and a mirror surface is formed on a side of the protrusion, the rough surface is formed. At the end of the protrusion. 3. The method of preparing a light guide plate according to claim 1, wherein the mirror surface and the rough surface are arranged at a staggered interval on the surface of the microstructure. 4. The method of preparing a light guide plate according to claim 1, wherein the rough surface of the inner wall of the mold cavity is 30% to 70% of the sum of the areas of the rough surface and the mirror surface, and the rough surface is 2。 Roughness is greater than or equal to 0. 2. 096109280 Form No. A0101 Page 13 of 18 0993278706-0