TWI342414B - Light guide plate - Google Patents

Description

1342414 December 14th, 2010, according to the positive replacement page, the invention description: [Technical Field] [0001] The present invention relates to a light guide plate applied to a backlight module of a liquid crystal display, and more particularly to a light guide plate for sidelight illumination . [Prior Art·] [0002]

Liquid crystal displays with side-lit backlight units are widely used in notebook computers, car monitors, and mobile phones due to their small size, light weight, and brightness. The backlight module of the liquid crystal display is an optical 'i·:, .V . 5 . K : - mechanism capable of converting a scattered point source or a line source into a uniform plane source. As the liquid crystal display is cold, reading the backlight with the light guide as the main technology, higher cost, lower power consumption, lighter and thinner, etc.

[0003] As shown in the first figure, the conventional backlight module 1_de] light source 10, light guide plate 12 and optical film, according to different functions, the light sheet respectively: reflective sheet 11, diffuser 13 and increase Hao K 14丨. The £11 series will not be ΙΠιθπΡΟϊυΠ'

The scattered light is further introduced into the light guide #3 to diffuse and evenly spread the light, thereby eliminating the bright area formed by the guiding structure, and the brightening sheet functions to concentrate the light and improve the brightness. [0004] An important component of the backlight module is a light guide plate, and its working principle is to use a transparent light guiding material such as polymethyl methacrylate (PMMA) or polycarbonate (PC) to emit light from a light source. One incident surface (one side) of the light plate is introduced, and the light is diffused to the entire surface by the principle of total reflection. When the light is irradiated onto the microstructure of the reflective surface (lower surface) of the light guide plate, the total reflection condition is destroyed, and the light will be removed from the light guide plate. The exit surface (upper surface) is emitted to complete the conversion to the surface light source, thereby functioning as an illumination. This lighting method 093125726 Form No. A0101 Page 4 / Total 40 Page 0993445505-0 1342414 ___—December 14th, 2010, the floor is replacing the page, the surface is high, and the volume is small, it is widely used in liquid crystal display products. [0005] The light guide plate microstructure manufacturing technology can be divided into two categories: printed and non-printed. The former uses the screen printing method to print the ink on the light guide plate to make the microstructure shape and distribution, while the latter directly uses the injection molding technology. The microstructure is designed in the mold, which is simplified in the process and high in precision. It is the mainstream technology for the current production of light guide plates. Non-printing methods are further divided into: chemical etching, laser direct writing, and precision machining.

[0006] As shown in FIG. 2A and FIG. 2B, from the perspective of the exit angle of the light beam, the design of the general light guide plate does not consider the angle control, so the light beam emitted from the exit surface of the light guide plate 12 will be away from the light source 1 — Exit at a fixed angle, not at a vertical. As shown in the third figure, the light beam emitted from the exit surface of the light guide plate 12 passes through the optical film such as the diffusion sheet 13 and the Zhanfan film 14, and is directed to the liquid crystal display in a direction perpendicular to the exit surface to meet practical use requirements. [0007] It can be understood that the light guide plate can be realized by considering the uniformity and the exit angle of the light guide plate to design the light guide plate so that the exit can be concentrated in a proper angle range perpendicular to the exit surface. The function of the traditional backlight module does not require a brightening piece or even a diffusion sheet, and at the same time meets the requirements of high brightness, low energy consumption and light weight. [0008] A light guide plate is disclosed in U.S. Patent No. 5,779,337, the entire disclosure of which is incorporated herein by reference. However, the V-shaped bump (groove) adopts a structure in which the height (depth) increases from the center to both sides, and the structure is disadvantageous for precision machining; and the light guide plate of the structure has no angle control function, so an additional multilayer optical film is required. To make the final 093125726 form number A0101 page 5 / total 40 pages 0993445505-0 1342414

Modified on December 14, 099, the replacement K output light can be emitted vertically. [0009] A light guide plate is disclosed in U.S. Patent No. 6,130,730, the disclosure of which is incorporated herein by reference. However, the light guide plate of the structure still has no angle control function, so it is necessary to add a multi-layer optical film so that the final exit light can be emitted vertically. [0010] As shown in the fourth figure, the US Patent No. 10 published on October 10, 2000

6, 1 29, 439 discloses a backlight module capable of realizing control of an exit angle, comprising: a side light source 40, a light guide plate 47, a bonding layer 46 formed on the exit surface of the light guide plate, and a section; Prismatic knot gold 5, the microprism junction

• · Λ > V I .: Λ : · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · However, Ji S.

The backlight group is difficult to prepare, and the light guide plate having the above microstructure is mass-produced. :< V

[0011] As shown in the fifth figure, the first published on October 10, 2002, the 2014.

U.S. Patent Application No. I discloses a type of light-emitting plate 5 〇 reflecting surface provided with a plurality of V-shaped grooves 5 4 and a plurality of V-shaped Γ ^ * • ? ^ sr, ^ ^···, The bumps 52, the V-shaped grooves 54 are arranged in the same direction. Although the V-shaped structure is formed on the reflecting surface and the emitting surface of the light guiding plate 50, the partial compression angle can be used to improve the brightness. However, the entire light guiding plate cannot control the outgoing beam to be perpendicular to the exit surface, and additional optical is needed. The film, and the brightness uniformity of the structure is also poor. [0012] In view of the above, it is necessary to provide a light guide plate having an uniform brightness without the need of an additional optical film and capable of controlling the outgoing light beam in a direction perpendicular to the exit surface. 093125726 Form No. 101 0101 Page 6 / Total 40 Page 0993445505-0 1342414 December 14th, 1999, according to the replacement page [Invention] [0013] The object of the present invention is to provide an optical beam control without the need for an additional optical film. A light guide plate having uniform brightness perpendicular to the direction of the exit surface. [0014]

In order to achieve the object of the present invention, a light guide plate is provided, the light guide plate has an incident surface, a reflective surface and an exit surface, the exit surface having a first V-shaped structure arranged regularly, the reflective surface having a plurality of and the exiting surface The second V-shaped structure in which the first V-shaped structure direction is perpendicular, the second V-shaped structure of the reflective surface has the same shape, and the farther away from the incident surface, the denser the V-type structure is arranged, and the larger the size. [0015] The light guide plate of the present invention further forms a third V-shaped structure on the incident surface, the third V-shape including a longitudinal alignment and a lateral alignment which are perpendicular or parallel to the second V-shaped structure along the length direction. [0016] The light guide plate of the present invention can further plate the high reflection film on the other three sides of the incident surface and the exit surface and the emission surface. [0017] Compared with the prior art, the light guide plate provided by the present invention is provided on the reflective surface thereof. The exit surface has a V-shaped structure, so it has the following advantages: First, the angle of the exit beam of the light guide plate can be controlled by controlling the angle of the second V-shaped structure of the reflective surface to be emitted perpendicular to the exit surface, or along the use The second V-shaped structure formed on the incident surface can be eliminated by controlling the arrangement density and size of the second V-shaped structure of the reflective surface to control the brightness uniformity of the emitted light; The shadow phenomenon generated by the light source; fourthly, the high-reflection film coated on the three sides except the incident surface and the exit surface and the reflective surface can improve the utilization of light energy, and is easier to control the exit angle. The light guide plate of the present invention is combined with the side light source. 093125726 Form No. A0101 Page 7 of 40 0993445505-0 1342414 On December 14th, the shuttle replacement page replaces the entire backlight module, which can flexibly realize the angle of the outgoing beam. Control and have the advantages of high brightness uniformity and low energy consumption. [Embodiment] The structure of the light guide plate of the present invention will be further described in detail below with reference to the accompanying drawings and the embodiments. Referring to FIG. 6 , the light guide plate 60 of the first embodiment of the present invention has an incident surface 61 (−side), a reflective surface 62 (lower surface), and an exit surface 64 (upper surface); A plurality of first V-shaped structures 644 are formed on the surface of the surface 64, and a plurality of second V-shaped structures 622 are formed on the surface of the reflective surface 62, and the second V-shaped structure of the reflective surface is 6 2:2巍: ^#^&44 directions to each other

Vertical [0020] The light guide plate Έ0 is a flat structure

(PC), polymethyl methacrylate (PMMA), or a light guide plate material synthetic material such as acrylic. [0021] Referring to the seventh figure, the y-type structure 644 formed in the rib-shaped structure is periodically arranged. The first V-shaped structure 644 has the same height and size ^: er 5 > _ £ parallel to each other . The plural

The apex angle 0 of a V-shaped structure 644 is between 70 and 120 degrees, and the height hi is not more than 200 microns. The height and apex angle can compress the exit angle. [0022] Referring to FIG. 6 and FIG. 8 together, the plurality of second V-shaped structures 622 protruding from the light guide plate reflecting surface 62 are V-shaped elongated bumps of different sizes. Each of the second V-shaped structures 622 is highly uniform in length along the same shape, i.e., its three angles (bottom angle 01, base angle 0 2 and apex angle 03) are the same. The base angle 0 1 ranges from 70 to 90 degrees, and the base angle 0 2 takes 093125726. Form number A0101 Page 8 of 40 0993445505-0 1342414 [0023]

[0024] 093125726 After December 14, 099, the replacement page is in the range of 15 to 50 degrees, and the apex angle Θ 3 ranges from 40 to 95 degrees. By controlling the bottom corner 01, the bottom corner Θ2, and the apex angle 0 3 , the angle of the exit beam of the light guide plate can be controlled to be emitted perpendicular to the exit surface 64 to the reflective surface 62 of the light guide plate, away from the incident surface 61 ( The farther the light source is, the denser the arrangement density of the plurality of second V-shaped structures 622, that is, the smaller the distance between the adjacent two second V-shaped structures 622, the larger the size of the plurality of second V-shaped structures 622. The second V-shaped structure 622 has a width dl ranging from 10 to 150 micrometers (refer to FIG. 8). The size of the range makes it difficult for the human eye to see the V-shaped structure on the light guide plate through the liquid crystal display, thereby eliminating the conventional backlight mode. A diffusion sheet in the group that causes a large energy loss. It will be appreciated that the width may be less than 10 microns, depending on the level of workmanship. If the light guide plate 60 has a phenomenon that the partial light transmittance is high, the size of the second V-shaped structure 622 can be reduced and the arrangement density of the second V-shaped structure 622 can be reduced. If the brightness is low, the size of the second V-shaped structure 622 can be increased and the arrangement density of the second V-shaped structure 622 can be increased. Therefore, the emission density and size of the second V-shaped structure 622 can be controlled to control the emission. Uniformity. Experiments have been carried out on a light guide plate having a V-shaped structure only on the reflecting surface: the light reflecting plate reflecting surface 62 and the second V-shaped structure 622 are plated with a highly reflective film (including a non-metallic film having high reflectivity and a metal film such as an aluminum film). , silver film, etc.), can improve the reflectivity of the reflected surface. The following is a comparative experiment of a light guide plate having a reflective sheet, an unplated high reflective film, and a non-reflective sheet, and having a highly reflective film, and having only a V-shaped reflective surface. Please refer to the ninth figure. Only the light guide plate with a V-shaped structure on the reflective surface and a reflection sheet allow many rays to exit at a large exit angle. This structure not only increases the form number A0101. Page 9 / Total 40 pages 0993445505-0 [0025 ] 1342414 On December 14, 099, the replacement page was replaced with an optical film, and the exit angle was dispersed. The eleventh figure is the distribution diagram of the exit beam exit angle of the ninth figure, and the exit angle distribution is relatively scattered. [0026] Referring to the tenth figure, only the light-reflecting plate with a V-shaped reflective surface is plated with a high reflective film, so that more light can be emitted at a smaller exit angle, thereby improving the utilization of light energy. The twelfth figure is the distribution diagram of the exiting beam exit angle of the tenth figure, and the exit angle distribution is relatively concentrated. [0027] By comparing the eleventh and twelfth figures, it can be seen that the angle of the exit after the coating is 铋 , , , , , , , , , . . . . 圭 圭 圭 圭 圭 圭 圭 圭 圭 圭 圭 圭 圭 圭 圭 圭 能

Shadow phenomenon. Referring to the thirteenth figure, in order to eliminate the subsidence, the present invention

Its height and shape are the same. The apex angle 0 5 of the third V structure 711 ranges from 70 to 120 degrees, and the height h2 does not exceed 200 microns. Shadowing can be clearly eliminated by designing its apex angle and height. [0029] Referring to the fifteenth and sixteenth drawings, the light guide plate according to the third embodiment of the present invention is arranged on the light guide plate of the first embodiment, and is arranged on the incident surface 81 along the horizontal direction of the X axis. Three V-shaped structure 811. The third V-shaped structure 811 arranged in this rule is a strip shape having a uniform height and shape. The 093125726 Form No. A0101 Page 10 of 40 0993445505-0 1342414 4

[The key after December 14th of the year ^3 V structure 8丨1 top angle Θ6 value range is 70~120 degrees, height h3 does not exceed 200 microns. Through the design of the apex angle and height, the shadow phenomenon can be clearly eliminated. The fourth embodiment of the present invention is applied to a 1.8-inch light guide plate on a mobile phone, and has the same structure as the light guide plate of the first embodiment. The light guide plate is made of a polymethyl methacrylate material. The minimum width of the V-shaped structure of the reflective surface of the light guide plate is 1 微米 micrometer' and the maximum width is 150 micrometers. The parameters of the first V-shaped structure of the exit surface are: height 50 μm apex angle 1 〇〇. The parameters of the third v-shaped structure of the incident surface are: apex angle 1 2 0 'width 0 · 2 mm. The light guide plate of the fourth embodiment will be described in detail below with reference to experimental data. (10) 31] The seventeenth figure is the emission angle distribution diagram of the V-shaped structure of the light guide plate only on the reflecting surface, and the eighteenth drawing shows the distribution angle distribution pattern of the V-shaped structure on both the reflecting surface and the emitting surface. Comparing the data of the seventeenth and eighteenth figures, the compression effect of the V-shaped structure on the exit surface can be clearly seen. [0032] The nineteenth figure is a curve of normalized light brightness with angle along the exit angle Φ in two directions of twist and 90 degrees, which reflects the angular distribution of the outgoing beam. It can be seen from the nineteenth figure that the angles of the two directions are all within 30 degrees, and most of the light beams are emitted perpendicularly to the direction of the light guide plate. Therefore, the light guide plate of the present invention reaches the angle of the conventional backlight module. Output requirements. [0033] The twentieth and twenty-first figures are normalized light intensity distribution diagrams obtained by adjusting the arrangement density and size of the V-shaped structure of the reflecting surface of the light guide plate, and it can be seen that the light beam propagates in the Y direction (see Figure 20) and the vertical beam propagation X direction (see Figure 21) have good uniformity in both directions, 093125726 Form No. A0101 Page 11 / Total 40 Page 0993445505-0 1342414 December 099 On the 14th, the core ridges were kept at more than 82%. [0034] The twenty-second graph is a graph showing the normalized luminance of a V-shaped structure of a different reflecting surface as a function of angle. By designing the shape of the V-shaped structure of the reflecting surface of the light guide plate, the zero angle of the peak value of the emitted light brightness is adjusted from 40 degrees to -20 degrees, from which it can be clearly seen that the light guide plate of the present invention can flexibly control the exit angle. The solid line in the figure indicates that the outgoing beam is obliquely emitted away from the light source, the dotted line indicates that the beam is closer to the vertical exit, and the dotted line indicates that the beam is close to the vertical exit, but close to the light source, the dotted line indicates that the beam is obliquely emitted near the light source, and the zero angle of the peak of the curve is respectively It is 40 degrees, 24 degrees, 2 degrees and -20 degrees. [0035]

An optical film such as a segment of a mat can be understood. The light guide plate of the present invention is applied to the incident surface, the reflective surface, and the precision machine: the work tool, and the reflective film of the conventional backlight module.

The guide structure of the invention is suitable for the diffusion sheet J on the _泠 structure, simplifies the system and improves the performance. At the same time, the distribution and density of the _-乂-type structure can control the emission of the bright 4# i ^ vertical and parallel to the two directions of the light source beam propagation:: the remainder, above 82%, through the reflective surface and the exit The surface v-shaped structure can be made to limit the beam exit angle of the two directions to within 30 degrees. [0036]

The backlight board of the invention can be applied to a backlight system of a liquid crystal display or a cold cathode tube light source, and controls the angle of the exit beam of the light guide plate to control the angle of the exit beam of the light guide plate to be perpendicular to the exit surface by controlling the angle of the V-shaped structure located on the reflective surface of the light guide plate. Controlling the uniformity of the emitted light by controlling the distribution density and size of the V-shaped structure of the reflecting surface; compressing the angle of the outgoing light by setting a V-shaped periodic structure perpendicular to the V-shaped structure direction of the reflecting surface on the emitting surface to improve the brightness; According to the light source condition, a V-shaped structure can be set on the incident surface to eliminate the shadow phenomenon caused by the replacement page light source due to the 093125726 form number A0101 page 12/40 page 0993445505-0 1342414 099. The high-reflection film is plated on the three sides except the incident surface and the reflective surface to improve the utilization of light energy (at least the reflective surface is coated with a highly reflective film). The function of the conventional entire backlight module is realized by using the V-shaped structure of the light guide plate. [Simple Description of the Drawings] [0037] The first figure is a schematic structural view of a conventional backlight module. [0038] The second A diagram is a schematic diagram of the exit angle of the outgoing light beam of the conventional light guide plate. [0039] The second B diagram is a perspective view of the exit angle of the exit beam of the second A diagram. [0040] The third figure is a schematic diagram of an exit angle of an outgoing beam of a conventional backlight module. [0041] The fourth figure is a schematic cross-sectional view of a light guide plate of the prior art U.S. Patent No. 6,129,439. [0042] The fifth drawing is a schematic cross-sectional view of a light guide plate of the prior art of U.S. Patent No. 2,020,150,860. [0043] FIG. 6 is a schematic structural view of a light guide plate according to a first embodiment of the present invention. [0044] The seventh figure is an enlarged schematic view of a portion VII of the sixth figure. 8 is an enlarged schematic view of another portion VI 11 of the sixth figure. [0046] The ninth drawing is a schematic view of the effect of the unreflected high-reflection film experiment on the exit angle of the light guide plate of the present invention. [0047] The tenth figure is a schematic diagram of the effect of the non-reflective sheet and the high-reflection film on the exit angle of the light guide plate of the present invention. [0048] The eleventh figure is a distribution diagram of the exit beam exit angle of the ninth diagram. [〇〇49] The twelfth figure is a distribution diagram of the exit beam exit angle of the tenth figure. 093125726 Form No. A0101 Page 13 / Total 40 Page 0993445505-0 H42414 December 14th, 2008, the shuttle replacement page [0050] [0055] [0055] [0056] [0057] Figure 13 is a schematic view showing the structure of a light guide plate according to a second embodiment of the present invention. The fourteenth figure is a partially enlarged schematic view of the thirteenth figure. Fifteenth is a schematic structural view of a light guide plate according to a third embodiment of the present invention. The sixteenth figure is a partially enlarged schematic view of the fifteenth figure. Fig. 17 is a view showing an angle distribution of an outgoing beam when the reflecting surface has a V-shaped structure in the fourth embodiment of the present invention. Figure 18 is a diagram showing the angle of the exiting beam when the reflecting surface and the emitting surface of the fourth embodiment of the present invention have a V-shaped structure: .., 〆; · The nineteenth figure is the fourth real version; Twenty drawings are the fourth embodiment of the present invention;

Light intensity curve. ‘ Celluloid The twenty-first embodiment is a normalized light intensity curve of the fourth embodiment of the present invention along the vertical direction: the direction of propagation of the light beam. Inteliectua'

[0059] The twenty-second figure is the fourth #fe' of the present invention having different V-shaped structures e·* , "· 1 light intensity-exit angle curve diagram, ' [main component symbol description] [0060] light guide plate : 60 [0061] Incident plane: 61 [0062] Reflecting surface: 62 [0063] Exit surface: 64 [0064] Second V-shaped structure: 622 093125726 Form number A0101 Page 14 of 40 0993445505-0 1342414 • [ [0069] [0069] [0069] First V-shaped structure: 644 Incident plane: 71 Third V-shaped structure: 711 Incident plane: 81 Third V-shaped structure: 811 December 14, 1999 Shuttle replacement page

093125726 Form No. A010丨 Page 15 of 40 0993445505-0

Claims (1)

丄 414 December 14, 2010, the replacement page VII, the scope of application for patents: , · ------------- I type of light guide plate, the light guide plate has an incident surface, a reflective surface And a first shot of the surface of the exit surface having a plurality of strip shapes regularly arranged; wherein the reflective surface has a plurality of strip shapes perpendicular to the direction of the first V-shaped structure of the exit surface a second V-shaped structure arranged in a regular manner, wherein the plurality of second V-shaped structures have the same shape, and the further away from the incident surface, the denser the density of the second V-shaped structure, the larger the size, the second v The width of the structure is in the range of 10 to 150 μm. The light guide plate according to claim 1, wherein the light guide ν -ν ' ., the plate is polycarbonate, polymethyl eucalyptus A synthetic resin material is used. The plate according to Item 1 of the patent application includes a flat plate type and a wedge type. Light guide The light guide plate according to claim 1, wherein the second V-shaped structure of the reflective surface of the light guide plate is a long bump of the same height ▲. The second V-shaped structure of the reflective surface of the light guide plate according to claim 1 is characterized in that the apex angle ranges from 40 to 95 degrees, and one of the ranges is 70 to 90. The illuminating plate of the first v-shaped structure of the exit surface of the light guide plate, wherein the angle of the apex angle of the first v-shaped structure of the light-emitting surface of the light guide plate is in the range of 15 to 50 degrees. It is 7〇~120 degrees. The light guide plate of claim 1, wherein the height of the first v-shaped structure of the exit surface of the light guide plate is less than or equal to 2 μm and greater than 0 μm. • The light guide plate as described in item 1 of the patent application scope, 纟中,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, There is a high reflective film. 9. The light guide plate of claim 1, wherein the light guide plate further comprises three sides, the three sides being plated with a highly reflective film. The light guide plate of claim 8 or 9, wherein the high-reflection film of the light guide plate is a metal film or a non-metal film. The light guide plate of claim 1, wherein the metal film of the light guide plate is an aluminum film or a silver film. The light guide plate of claim 1, wherein the incident surface of the light guide plate forms a plurality of elongated strip-shaped third V-shaped structures, the third V-shaped structure being parallel to the second V-shaped structure structure. 13. The light guide plate of claim 12, wherein the apex angle of the third V-shaped structure of the light guide plate ranges from 70 to 12 degrees. 14. The light guide plate of claim 12, wherein the height of the third V-shaped structure of the light guide plate is less than or equal to 200 micrometers and larger than 〇 micrometers. 093125726 Form No. A0101 Page/Total 40 Page 0993445505-0