TWI273289B - Light guide plate and surface light source device using the same - Google Patents

Abstract

A surface light source device includes a light guide plate, a lamp and a lamp cover enclosing a part of the outer circumferential surface of the lamp. The light guide plate can direct light directly coming from the lamp and reflected by the lamp cover to output, and can enhance brightness and uniformity of outputting light. The light guide plate includes an incident surface, a light emitting surface crossing to the incident surface, a bottom surface being opposite to the light emitting surface. The bottom surface has a plurality of light diffusion recesses therein, wherein top surfaces of the light diffusion recesses form a specific curved face.

Description

1223289— V. INSTRUCTIONS (1) [Technical field to which the invention pertains]

this invention! Regarding the light source device and the light guide plate thereof, the light guide plate having a high light emission and the surface light source using the light guide plate [Prior Art] Since the liquid crystal display device is light, it is used for a notebook computer, a mobile phone, and a device. The display function is realized because the liquid crystal itself does not emit light. The advantages of thinness, low power consumption, etc., should be widely used in modern information such as personal digital assistants.

The conventional surface light source device comprises a light source and a light guide plate, and the light source is disposed opposite to the light incident surface, and the light guide plate guides the transmission of the light beam from the light source. The light source or the point light source is converted into a surface light source. The bottom of the light guide plate has a plurality of dots ??? to destroy the total reflection of the light beam transmitted inside the light guide plate, and to scatter it to improve the uniformity of the light beam emitted from the light guide plate, and to improve the overall performance of the surface light source device. The density and size of the dots can be designed differently to suit different surface light source devices.

A conventional surface light source device can be referred to the U.S. Patent No. 6, 4 4 3, 5 8 3 (refer to the first figure) published on September 3, 2002, the surface light source device The tube 11 0 , a lamp cover 丨 2 围绕 surrounding the lamp tube 〇 and a light guide plate 2 一端 fixed to the lamp cover 120 at one end. The light guide plate 200 includes a light incident surface 2〇, a bottom surface 02, and a light exit surface 203, wherein the light tube 110 is disposed opposite to the light incident surface 2〇1. During operation, the light beams from the lamp tube 110 and the lamp cover 120 are transmitted inside the light guide plate 20 and converted into a surface light source to be emitted through the light exit surface 2〇3. In order to increase the utilization ratio of the optical unit, the surface light source device 1 further includes a reflection plate 21 0 disposed on the side of the bottom surface 202 of the light guide plate 20 to reflect from the bottom surface 202.

Page 6 1222282__ V. Part of the beam of the invention (2). The surface light source device 100 sequentially arranges a diffusion plate 2 2 0, a first plate 2 3 〇 and a second plate 24 于 on the light-emitting surface 2 〇 3 side of the light guide plate 20 (), and the diffusion plate 220 is used. In order to enhance the uniformity of the light beam emitted from the light guide plate 2, the rafters 230 and 240 converge to enhance the brightness of the light guide plate 2. However, the surface light source device 100 needs to use the prism plates 23 and 24 to gather the light beam emitted from the light-emitting surface 203 of the light guide plate 20 to improve the brightness, which makes the junction, material cost and assembly inconvenient. In addition, the surface light source device has a 〇〇:2 multiple optical interface, and the beam needs to undergo multiple optical effects during the process to form a large optical loss, which affects the brightness of the surface light source device. Single, Si: This: For a light-emitting plate with a high degree of brightness and a simple structure, it is necessary to have a convenient surface light source. The excellent light guide plate of the present invention provides a high light-emitting luminance and optical performance. The present invention provides a surface light source device which is excellent in cost, low in cost, and excellent in optical performance. The bright surface light source device includes a light guide plate, and the light plate includes at least one exit surface and a surface for receiving the light/the original v and guiding the light beam to exit, and intersecting the incident surface. The source is disposed opposite to the incident surface. The opposite surface of the f-plane opposite to the bottom surface, the scattering surface of the pit constitutes a curved surface r for the mouth: a number of shouting 'and the complex concave, the scattering surface of the plurality of pits;::: the scattered beam. Face or arc face. The concave surface of the pit can be a part of a cylinder, which is cylindrical, spherical, round, or rectangular.

1973 Measure _ 5, invention description (3) or cube. The plurality of pits may be evenly distributed on the bottom surface, and the size and density may be gradually increased in a direction away from the incident surface. The light guide plate may be a flat plate shape or a wedge shape light guide plate. The light source can be a line source or a point source. The surface light source device may further include a reflecting plate, a diffusing plate and a slab. Compared with the prior art, the bottom surface of the light guide plate of the present invention is distributed with a plurality of pits' and the scattering surface of the plurality of pits forms a curved surface of a specific shape, and the light beam scattered by the pits can be concentrated, so that the light transmittance of the light guide plate is higher than that of the light guide plate. High, and with a certain degree of uniformity. The surface light source device of the present invention uses a combination of a light guide plate and a light source. Instead of using a fascia or using only one raft, the structure is simple, the cost is low, and the energy loss of the light beam is small. [Embodiment] Please refer to the second embodiment, which is a first embodiment of the surface light source device of the present invention. The surface light source device 10 includes a light guide plate 20 and two light sources 3A. The light guide plate 2 includes two incident surfaces 21, an exit surface 22 connected to the incident surface 21, and a bottom surface 24 opposite to the exit surface 22. The light source 30 includes a lamp tube 31 and a reflector 32 partially surrounding the lamp holder 31. The two light sources 3 are respectively disposed opposite to the two incident surfaces 2 1 of the light guide plate 2 . Referring to the second and third figures together, the bottom surface 24 of the light guide plate 2 is provided with a plurality of dimples 23. The plurality of dimples 23 are used to scatter the light beam, to destroy the total reflection condition of the light beam entering the light guide plate 2 from the incident surface 21, and to improve the luminance and uniformity of the light beam emitted from the exit surface 22. The plurality of recesses 23 are evenly distributed on the bottom surface 24 of the light guide plate 20, which is rectangular and

T97^9RQ___ V. Invention Description (4) "" ' " One can be cylindrical, round table, spherical or cube. The diffusing surface 25 of the plurality of dimples 2 3 forms a curved surface which is a partial cylindrical surface for collecting the light beam scattered by the dimples 2 3 to enhance the luminance of the outgoing beam of the exit surface 22. The bottom surface 24 of the light guide plate 20 has a reflective film (not shown), which is a multilayer film formed by alternately forming Si〇2 and Τι 02, and reflects the light beam projected thereon to prevent the light beam from being emitted from the light guide plate 2 The bottom surface 24 escapes, thereby reducing the energy loss of the light beam and improving the overall optical performance of the light guide plate 20. The reflective film can be formed by a chemical vapor deposition method, an electron beam evaporation method, a sputtering method, or the like, and has a reflectance in the visible light region of 98% or more. Compared with the prior art, since the bottom surface 24 of the light guide plate 2 of the present invention distributes a plurality of pits 23, and the scattering surface 25 of the pit 23 forms a curved surface of a specific shape, the light beam scattered by the pit 23 is scattered, thereby making the light guide plate 2 The brightness is higher than that of the south and has a certain uniformity. The surface light source device of the present invention uses a combination of the light guide plate 20 and the light source 3〇, which has a simple structure, a low cost, and a small energy loss of the light beam. Please refer to the fourth and fifth figures, which are a second embodiment of the surface light source device of the present invention. The surface light source device includes a light source 3 and a light guide plate 4 . The light guide plate 40 includes an incident surface 41 and a bottom surface 44 intersecting the incident surface 41. The light source 30 can be a line source (such as a cold cathode fluorescent tube) or a point source (such as a light emitting diode 2' The bottom surface 44 is provided with a plurality of dimples 4 3 . The scattering surface 45 of the dimples 4 3 forms a curved surface which is partially cylindrically shaped to converge the light beam scattered by the dimples 43. The dimples 43 The size and the density are gradually increased from the incident surface 41 to improve the uniformity of the light beam of the light guide plate 4 and the surface light source coating 11. The bottom surface 44 has a reflective film.

197^9^_____ 1-5, invention description (5) (not shown), the reflective film is a multilayer film formed by alternately forming Si 02 and Ti 02. Please refer to the sixth and seventh figures, which are the third embodiment of the surface light source device of the present invention. The surface light source device 12 includes a light source 30 and a light guide plate 6A. The light guide plate 60 is a wedge-shaped light guide plate, and includes an incident surface and a bottom surface 64 obliquely connected to the incident surface 61. The light source 30 is disposed opposite to the incident surface 61. The bottom surface 64 is distributed with a plurality of dimples 6 3 . The plurality of dimples 6 3 are evenly distributed on the bottom surface 64 ′ of the light guide plate 60. They are cubic, and may be cylindrical, circular, spherical or rectangular. The scattering surface 65 of the plurality of pits 6 3 forms a curved surface which is a partial cylindrical surface for collecting the light beams scattered by the pits 63, thereby enhancing the luminance of the light beam emitted from the light guide plate 60. The bottom surface 64 of the light guide plate 60 has a reflective film (not shown) to prevent the light beam from escaping from the bottom surface 64 of the light guide plate 60, thereby reducing the energy loss of the light beam and improving the overall optical performance of the light guide plate 6. Please refer to the eighth embodiment, which is a fourth embodiment of the surface light source device of the present invention. The surface light source device 13 includes a light source 30 and a light guide plate 70. The structure of the light guide plate 7 is substantially the same as that of the light guide plate 60 shown in Fig. 6, but the bottom surface 74 has no reflection film, and a reflection plate 78 is provided to prevent the light beam from escaping from the bottom surface 4. In order to further enhance the uniformity of the beam luminance of the surface light source device 13 , a diffuser plate 80 is disposed on the side of the exit surface 72 of the light guide plate 70 to further converge the light scattered by the diffuser plate 80 to improve the surface light source device 13 . The light-emitting luminance 'a prism plate 90 may be disposed on the other side of the side adjacent to the diffusing plate 80 and the exit surface 7 2 . Please refer to the ninth drawing, which is another embodiment of the light guide plate of the present invention. The guide

Page 10 V. Description of the Invention (6) The light plate 50 and the bottom surface 54 are distributed in the same shape, and the structure of the light guide plate 20 is substantially the same, and the bottom surface 54 is provided with a plurality of pits 53. The complex number 5: 5 shape 0 =: 54, which is a rectangular shape, or a circle can be formed into a curved surface to enhance the reflection and escape, and the learning performance. The scattering surface of the plurality of pits 53 is π 擗 = 5 =, the convergence is scattered by the pit 53 = light ... the bottom surface 54 of the light guide plate 50 reduces the energy loss of the beam 2 first i [the bottom surface 54 of the light guide plate 50 Consumption, ^ 咼 light guide plate 50 of the overall light above, a patent application. Only if you are familiar with the modification or change of the technical effects of this case, the present invention has indeed met the invention patent. # 爰According to the law, the above is only the preferred embodiment of the present invention, and the person in the case is in the spirit of the invention. Whitening should be included in the scope of the following patent application. T97^9RQ_ BRIEF DESCRIPTION OF THE DRAWINGS The first figure is a cross-sectional view of a conventional surface light source device. The second drawing is a perspective view of a first embodiment of the surface light source device of the present invention. The third drawing is a cross-sectional view of the surface light source device shown in Fig. 2 along the direction of 11 I - 111. Figure 4 is a perspective view of a second embodiment of the surface light source device of the present invention. Fig. 5 is a cross-sectional view of the surface light source device shown in Fig. 4 in the V-V direction. Figure 6 is a perspective view of a third embodiment of the surface light source device of the present invention. Figure 7 is a cross-sectional view of the surface light source device shown in Figure 6 taken along the direction of V I I - V I I . Figure 8 is a cross-sectional view showing a fourth embodiment of the surface light source device of the present invention. Figure 9 is a partial cross-sectional view showing another embodiment of the light guide plate of the present invention. [Component Symbol Description] Surface Light Source Device 1 0, 11, 1 2, 1 3

Page 12 Light guide plate 20 > 40 > 50 > 60 > 70 Incidence surface 21 , 41 > 61 Exit surface 22 , Ί 2 Pit 23 , 43 > 53 , 63 Bottom surface 24 > 44 , 54 , 64 74 scattering surface 25 > 45, 55, 65 light source 30 lamp 31 reflector cover 32 anti-scatter plate 78 diffuser plate 80 plate 90

Claims (1)

T7737RQ__ VI. Patent Application Range 1. A light guide plate comprising: at least one incident surface for receiving a light beam; an exit surface intersecting with the incident surface for guiding the light beam to exit; and a bottom surface opposite to the exit surface; Wherein, the bottom surface is distributed with a plurality of pits, and the scattering surface of the plurality of pits forms a curved surface for collecting the light beams scattered by the pits. 2. The light guide plate of claim 1, wherein the concave surface of the concave surface forms a cylindrical surface. 3. The light guide plate of claim 1, wherein the scattering surface of the pit is a curved surface. 4. The light guide plate of claim 1, wherein the pit may be cylindrical, spherical, truncated, rectangular or cubic. 5. The light guide plate of claim 1, wherein the plurality of dimples are evenly distributed on the bottom surface. 6. The light guide plate of claim 1, wherein the size and density of the plurality of pits gradually increase in a direction away from the incident surface. 7. The light guide plate of claim 1, wherein the light guide plate is a flat plate light guide plate. 8. The light guide plate of claim 1, wherein the light guide plate is a wedge-shaped light guide plate. A surface light source device, comprising: at least one light source for emitting a light beam; and a light guide plate comprising: at least one incident surface for receiving a light beam; Page 13 12732, ^9_16, the scope of application for patents ' ^1 "" an exit surface, the intersection with the incident surface is used to guide the beam exit; a bottom surface is opposite to the exit surface; The number of four pits, and the scattering surface of the plurality of pits constitute a curved surface for collecting the light beams scattered by the pits. The surface light source device of claim 9, wherein the scattering surface of the pit is a curved surface portion of a cylindrical surface. The surface light source device according to claim 9, wherein the scattering surface of the pit is a curved surface. The surface light source device of claim 9, wherein the pit may be cylindrical, spherical, truncated, rectangular or cubic. The surface light source device of claim 9, wherein the plurality of pits are evenly distributed on the bottom surface. The surface light source device of claim 9, wherein the size and density of the plurality of pits gradually increase in a direction away from the incident surface. The surface light source device of claim 9, wherein the light guide plate is a flat plate shape or a wedge-shaped light guide plate. The surface light source device of claim 9, wherein the light source is a line source or a point source. The surface light source device of claim 9, further comprising a reflecting plate on a side of the bottom surface of the light guide plate. The surface light source device of claim 17, further comprising a diffusing plate and a prism plate on the exit surface/side of the light guide plate. Page 14