KR20030035158A - Light Guided Panel of Plane Surface Illuminant System - Google Patents

Abstract

PURPOSE: A light guide panel of a surface light source device is provided to uniform distribution of light luminance and prevent time loss according to correction of patterns in a dark area and moire related to a specific pattern. CONSTITUTION: A main scattering reflective pattern is formed of circular first patterns(10) separated from each other on a rear surface of a light guide panel and forming space areas(20). A sub-scattering reflective pattern is formed of a plurality of linear second patterns(210) formed between adjacent first patterns by considering a distance from a light source to the rear surface of the light guide plate, and an area ratio of the main scattering reflective pattern and the sub-scattering reflective pattern in normal areas and the space areas.

Description

Light Guided Panel of Plane Surface Illuminant System

The present invention relates to a light guide plate of a surface light source device, and more particularly, to a light guide plate of a surface light source device, characterized in that it is possible to adjust the scattering reflection area ratio of its rear surface.

In a backlight system for various display devices including an LCD display device, an advertising display device, or illumination, which is a surface light source device, a light guide panel, which is a primary propagation means of light emitted from a light source, has a shape on the rear surface thereof. Therefore, it can be manufactured in various forms such as flat plate and wedge shape. In such various types of light guide plates, a pattern is formed by a printing or non-printing method in various shapes, sizes, and numbers in a specific area or a whole area of the rear surface so that a uniform distribution of high luminance and luminance of light is more efficiently achieved.

In the conventional flat type light guide plate, a pattern is formed on the back surface of the light guide plate by silk printing, screen printing, or the like so that the back surface is formed into a flat plate so as to reflect or scatter light emitted from one or both light sources of the light guide plate. It is made to radiate | emit uniformly from the back surface of this light guide plate. Here, in order to effectively reflect and scatter light inside the light guide plate, a light guide plate for a backlight is manufactured by printing a mixture of materials reflecting light such as glass beads in a suitable ratio in a printing ink. . However, at present, the printed light guide plate having a flat plate shape has a limitation in forming a pattern, and thus, there is a problem to achieve a luminance increase according to the trend of increasing size and weight in recent years.

Therefore, in the light guide plate which is most widely employed in the backlight system for notebook computers, the back surface is formed into a wedge shape, and reflection and scattering are performed. Here, a non-printing method of injection molding is applied to the back surface by engraving a specific pattern on screen printing or a mold core part in various ways, and at this time, the pattern formed by non-printing by injection molding or the like is printed. It is known that the brightness is improved by about 10% compared to the light guide plate, but when the back surface is formed in a simple wedge shape, there is a problem in that the difficulty of designing the pattern for increasing the defective rate of pattern formation and uniformity of the brightness is further increased.

In addition, in order to improve the brightness of the light and to reduce the weight of the device, the light guide plate is formed in a bidirectional wedge shape by an optical design. In this case, although it is applicable to a backlight system, the light guide plate is used in designing a pattern by conventional printing or non-printing. There is a problem that it is very difficult to achieve uniform luminance on the entire surface. For example, in screen printing, printing is poor as the angle changes sharply at the center of both wedges.

According to the method of forming a pattern on the back of the conventional flat or wedge-shaped light guide plate divided into a printed light guide plate or a non-printing light guide plate as follows.

A printed light guide plate is generally printed in a dot pattern while varying its size in accordance with a distance from a light source, thereby uniformly inducing the brightness of light emitted from the rear surface of the light guide plate. Here, when the light emitted from the lamp is incident on the light guide plate, the incident light amount decreases as the distance from the light source increases, so that the light emitted second by using the light guide plate as a medium for propagation is arranged in each region of the light guide plate. Scattered to exit the front of the light guide plate. As a result, since the amount of light emitted to the light guide plate and the brightness of the light are proportional to the area of the pattern, the luminance emitted from the front surface of the light guide plate actually has a relationship proportional to the product of the area of the designed pattern and the intensity of the light incident from the light source. In addition, in order to obtain a uniform luminance distribution in the entire region of the light guide plate, it is necessary to adjust the size ratio of the specific pattern or the area ratio of the pattern per unit area according to the distance from the light source. Therefore, in the related art, by dispersing patterns as the distance from the light source increases, the luminance distribution for each part of the light guide plate is controlled to compensate for the luminance by overlapping the scattered light. At this time, it is necessary to greatly reduce the size of the pattern in order to reach the dense state of the patterns or the distance between the patterns. Therefore, the pattern of the conventional printed light guide plate has a difficulty in forming the pattern because the size of each pattern is so small that printing is impossible.

The non-printing light guide plate roughens its back surface by injection molding, stamping, pressing, thermal transfer, roller, sandblasting or other methods. In addition, patterns of various shapes are formed, and in addition to the time required for rearrangement or modification of the pattern for each part for the uniformity of luminance of the entire surface of the light guide plate, as well as an increase in the manufacturing cost of a mold or a mask, a model change or a new product release Every time there is a fear of huge development costs.

On the back of the light guide plate, machining methods such as forming a concave pattern or a convex pattern or processing methods such as V-cutting have recently been applied to a non-printing light guide plate. The core technology that can finely control the brightness of the brightness is still a challenge.

On the other hand, the effective light emitting area of the lamp currently employed in the backlight system for LCD displays is shorter than the width of the light guide plate, and due to its own problem, the luminance difference between the center and both ends differs by at least 10%. The dark region is essentially accompanied by a predetermined region of the light guide plate corresponding to. The pattern design of the part where the dark region is generated is very demanding and is usually employed as a product only after many trials and errors. For this reason, the size of the scattering reflection pattern on the rear surface of the light guide plate is formed to be extremely large or densely designed, but there is a limit in setting the pattern area ratio of the dark area as large as possible.

In addition, in general, a backlight unit for an LCD display device essentially laminates a prism sheet having a prism face on a diffusion sheet in order to improve luminance of a conventional light guide plate. Lamination of protective sheets for preventing external damage of acrylic is almost common. At this time, due to the interference or reinforcement, which is an optical phenomenon, the diffusion pattern is further laminated due to the phenomenon in which the pattern pattern appears even after the diffusion sheet is laminated on the entire surface of the light guide plate. Here, when the pattern design and the matching relationship between the pattern and the pattern must be sufficiently considered, unnecessary patterns, that is, the generation of moires (moire) can be prevented, and many restrictive factors for various pattern designs follow.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a light guide plate capable of controlling a scattering reflection area ratio by forming a subscattering reflection pattern on a rear surface of scattering and reflecting light.

1A to 1D are plan views showing patterns formed on the light guide plate of the present invention;

2A to 2C are exemplary views showing shapes of patterns formed on the rear surface of the light guide plate of the present invention;

3 is an exemplary view of forming a sub-scattered reflection pattern without printing in a region between main scattered reflection patterns formed by printing according to the present invention;

4 is a schematic view showing a light guide plate having a rear surface in a planar shape according to the present invention;

5A to 5E are schematic views showing a light guide plate having a wedge shaped rear surface according to the present invention; And

6A and 6B are schematic views illustrating a light guide plate having a curved back surface according to the present invention.

The present invention is to achieve the object as described above, the light guide plate of the surface light source device having a back to which the light is scattered and reflected according to the present invention, the main scattering reflection consisting of first patterns formed on each of the back spaced apart And a sub-scattered reflection pattern consisting of a second pattern formed in a region between each of the first patterns and other first patterns adjacent to each of the first patterns.

In addition, the main scattering reflection pattern or the sub-scattering reflection pattern is linear, circular or polygonal.

In this case, the first pattern or the second pattern is formed to be concave or convex with respect to the rear surface, and has a cross section of linear, circular or polygonal.

Here, the first pattern or the second pattern is formed by printing a dot on the rear surface, and may be linear, circular or polygonal.

Further, the diameter of the circular first pattern is made of 30 μm to 1500 μm.

Further, the area of the sub-scattered reflection patterns is 1-20% of the area of the main scattered reflection patterns.

Moreover, the said back surface of the said light guide plate consists of a flat surface.

In addition, the light guide plate has one side and the other side facing the one side and having a height lower than the height of the one side, and the rear surface of the light guide plate connects the bottom of the other side from the bottom of the one side. It is a one-way wedge made of an inclined surface.

In addition, the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate has a first inclined surface inclined upwardly from the bottom of the one side surface, and one end thereof is the first side surface. It is a bi-directional wedge shape consisting of a second inclined surface inclined upward at the bottom of the other side surface to be mated with one end of the inclined surface.

In addition, the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate has a first inclined surface inclined upwardly from the bottom of the one side surface, and one end thereof is the first side surface. It is a bi-directional wedge shape consisting of a second inclined surface inclined upward at the bottom of the other side so as to occlude one end of the inclined surface and the curved surface from the inside.

In addition, the light guide plate has one side surface and the other side surface opposite to the one side surface, and the rear surface of the light guide plate is connected to the first plane formed at the bottom of the one side surface and is upwardly inward connected to the first plane. A first slope inclined, a second plane formed at the bottom of the other side, and one end thereof is connected to the second plane so that one end of the first inclined surface interlocks with the second slope inclined upwardly; It is a bidirectional wedge.

In addition, the light guide plate has one side surface and the other side surface opposite to the one side surface, and the rear surface of the light guide plate is connected to the first plane formed at the bottom of the one side surface and is connected to the first plane and upwards inwardly. A first slope inclined, a second plane formed at the bottom of the other side, and a second inclined upwardly in connection with the second plane such that one end thereof is mated from one end of the first slope to the curved surface from the inside It is a bidirectional wedge shaped with an inclined surface.

In addition, the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate is formed of a curved surface having an arc of a cross section so as to be connected from the bottom of the one side to the bottom of the other side. .

In addition, the light guide plate may have one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate may include a first plane formed at the bottom of the one side and a second part formed at the bottom of the other side. It consists of a flat surface and a curved surface consisting of an arc of a cross section so that the first plane and the second plane are connected.

Hereinafter, an embodiment of a light guide plate of a surface light source device according to the present invention will be described in detail with reference to the drawings.

1A to 1D are plan views illustrating patterns formed on the light guide plate of the present invention.

FIG. 1A is a plan view illustrating a rear surface of a light guide plate in which only circular first patterns are formed, and FIGS. 1B to 1D are linear second patterns in a region between circular first patterns formed according to FIG. 1A. These are top views which show the back surface of the light guide plate in which the sub subscattering pattern was formed. Here, although the formation of the first pattern and the second pattern is printing, the first pattern or the second pattern may be formed without printing.

Referring to FIG. 1A, the circular first patterns 10 are spaced apart from each other to form main scattering reflection patterns 100 in a continuous hexagonal array while forming interregions 20 therebetween.

1B to 1D, an area in which a non-uniform distribution of light emitted from the rear surface of the light guide plate on which the main scattering reflection pattern 100 of FIG. 1A is generated occurs, that is, an area between each of the first patterns 10 ( 20, the linear second pattern 210 is inserted to control the area ratio to the limit and induce uniformity of the luminance distribution. The insertion of the second patterns 210 takes into consideration the distance from the light source to the entire area of the light guide plate, and includes a normal area, that is, an area where a pattern is formed and an area between the first pattern 10 and the first pattern 10. It is made by finely adjusting in consideration of the area ratio of the main scattering reflection pattern and the sub-scattering reflection pattern in (20).

In this case, as shown in FIG. 1B, linear subpatterns are formed by inserting linear second patterns 210 in regions between each of the first patterns 10, or as shown in FIG. 1C, as shown in FIG. 1C. By inserting the linear second pattern 210 in each inter-region 20 to form a hexagonal but several polygonal or circular sub-scattered reflection patterns in the figure it is possible to adjust the area ratio of the pattern. Here, the insertion of the second pattern 210 may be formed in whole or in part with respect to the rear surface of the light guide plate, and the sub-scattered reflection pattern formed of the second patterns 210 is also shown in a continuous arrangement in the drawing. It is not intended to be limiting, which may lead to discontinuous arrangements.

In addition, the sub-scattered reflection pattern is formed step by step from FIG. 1A to FIG. 1D. Finally, as shown in FIG. 1D, the area 20 between the second patterns 210 is reached to reach the limit, thereby increasing the area ratio of the entire pattern. It may be made high, or you may select and form the shape of any pattern in FIGS. 1A-1D steplessly. Therefore, the second patterns 210 of the sub-scattered reflection pattern, which are formed independently of the first patterns 10 of the main scattered reflection pattern, can freely adjust the area ratio of the pattern formed per unit area, thereby reducing the local or overall brightness. It is to control the brightness at the same time. In addition, in the main scattering reflection pattern and the sub-scattering reflection pattern having the area ratios adjusted by the second patterns 210 formed as described above, the light emitted from the lamp is scattered and reflected to reflect the amount of light emitted from the front surface of the light guide plate. It can be made uniform.

Meanwhile, in the above-described embodiment, the first pattern 10 of the main scattering reflection pattern is printed in dots on the rear surface of the light guide plate of the present invention, but both printing and non-printing are possible according to the shape of the light guide plate described later. The shape of 10) is not largely dependent on its shape, and is not affected by its size within the range of 30 µm to 1500 µm in diameter on the basis of a circular pattern. In the case of the printing type, the shape is preferably circular or hexagon, and in the case of the non-printing type, the shape is preferably the square or the circle or the hexagon.

In addition, the first patterns 10 may be freely changed in the vertical direction and the horizontal direction of the light source to control optical characteristics, and may be formed by introducing an area function including a trigonometric function. For example, in the case of a light guide plate of a 17-inch surface light source device, the size of the pattern to be formed is preferably about 70 μm in diameter when the area ratio is low based on the circular pattern, and the diameter is approximately when the area ratio is high. It is preferably made at 1450㎛. Here, when the light guide plate for backlight is 10 inches or less, when the area ratio is high, the diameter of the circular first pattern 10 may be 70 µm or less. When the light guide plate for backlight exceeds 17 inches, the diameter of the circular first pattern 10 may be 1450 µm or more when the area ratio is high.

In addition, the second pattern 210 inserted as the sub-scattered reflection pattern for the luminance fine compensation is not limited in shape and size, but the area ratio of the second pattern 210 to the main scattered reflection pattern is effectively applied for the fine compensation for the luminance. It should be formed up to 20% or less. In this case, only the second patterns 210 are formed in the region where luminance compensation is required on the light guide plate, that is, the specific region or the entire region, thereby controlling the optical characteristics without modification of the first patterns 10.

Further, the present invention is not limited to the case where the first pattern of the main scattering reflection pattern according to the present invention is circular as in the above embodiment, and the shape of the second pattern of the sub-scattering reflection pattern is also not linear. Examples of the shape of the patterns formed on the rear surface of the light guide plate as the branch shape can be replaced will be described in detail with reference to the drawings.

2A to 2C are exemplary diagrams illustrating shapes of patterns formed on a rear surface of the light guide plate of the present invention. 2A illustrates a case in which the first pattern 10 of the main scattered reflection pattern is circular, and FIG. 2B illustrates a case in which the first pattern 10 of the main scattered reflection pattern is triangular, and FIG. 2C illustrates a first pattern of the main scattered reflection pattern. This is the case when the pattern 10 is a rectangle. In this case, the first pattern 10 has been described by forming only a circle, a triangle, a rectangle, but may be formed of various polygons.

Referring to FIGS. 2A to 2C, in FIG. 2A, the first patterns 10 may be formed in a circular shape to be spaced apart from each other, and the first patterns 10 may be spaced apart from each other. As shown in (2), the sub-scattering pattern forming a hexagonal arrangement by inserting the second pattern 210 of circular or linear shape is inserted.

In FIG. 2B, the first patterns 10 are formed in a triangle to be spaced apart from each other, and a linear line of (1) of FIG. 2B, a circle of (2) of FIG. 2B, or a space between respective regions formed by the first patterns 10 are formed. The triangular second patterns 210 of FIG. 2B form subscattering patterns in various shape arrangements.

In FIG. 2C, the first patterns 10 are formed in a rectangle to be spaced apart from each other, and the quadrangles of the rectangle of FIG. 2C or the linear line of FIG. The two patterns 210 form subscattered reflection patterns in an array of various shapes that are continuous or discontinuous.

At this time, the arrangement of the main scattering reflection pattern and the sub-scattering reflection pattern can be arranged in a variety of linear, circular, polygonal not limited to the above shown, the first pattern 10 or the second pattern 210 is also shown In addition to shape, it can be replaced by several polygons of various sizes. Here, although a pattern of a certain shape is mainly formed by printing, but if the pattern is formed by non-printing, it may be formed in various three-dimensional shapes that are concave or convex with respect to the rear surface and have a circular or polygonal cross section.

Further, the sub-scattered reflection pattern is formed by printing and inserted in the region between the main scattered reflection patterns, but may be formed without printing to adjust the area ratio of the main scattered reflection pattern.

3 is an exemplary view of forming a sub-scattered reflection pattern without printing in the region between the main scattered reflection pattern formed by printing according to the present invention.

Referring to FIG. 3, circular second patterns 210 are formed concavely and unprinted in a region between each of the hexagonal first patterns 10 of the main scattering reflection pattern formed by printing. As described above, the first pattern 10 or the second pattern 210 may be formed by printing or non-printing as described above.

Hereinafter, the shape of the rear surface of the light guide plate forming the patterns according to the present invention will be described in detail with reference to the drawings.

4 is a schematic view showing a light guide plate having a rear surface in a planar shape according to the present invention.

Referring to FIG. 4, one side surface 310 and the other surface 320 of the light guide plate 300 facing each other are formed to have a constant thickness, and the rear surface 330 may form a plane. In this case, the main scattering reflection pattern and the sub-scattering reflection pattern may be both printed or unprinted on the rear surface 330 of the light guide plate 300 formed as a plane. In this case, in order to obtain the light guide plate 300 having high luminance, a pattern must be formed to have a high area ratio.

5A to 5E are schematic views illustrating a light guide plate having a wedge-shaped rear surface according to the present invention. In this case, Figure 5a is a one-sided wedge-shaped backside of the light guide plate, Figures 5b to 5e is a two-sided wedge-shaped backside of the light guide plate.

Referring to FIG. 5A, the light guide plate 300 has one side surface 310 and the other side surface 320 facing the one side surface 310 and having a height lower than that of the one side surface 310. The rear surface 330 of the one-sided wedge-shaped inclined surface connecting the bottom of the other side 320 from the bottom of the side 310.

Referring to FIG. 5B, the light guide plate 300 has one side 310 and the other side 320 facing the one side 310, and the rear surface 330 of the light guide plate 300 is one side 310. The first inclined surface 331 inclined upwardly from the bottom of the second inclined surface, and the second inclined surface 332 inclined upward in the bottom of the other side surface 320 such that one end thereof is engaged with one end of the first inclined surface 331. It consists of a bidirectional wedge.

Referring to FIG. 5C, the light guide plate 300 has one side 310 and the other side 320 facing the one side 310, and the rear surface 330 of the light guide plate 300 is one side 310. The first inclined surface 331 which is inclined upwardly from the bottom of the second slope and the second inclined surface which is inclined upward at the bottom of the other side surface 320 such that one end thereof is engaged with one end of the first inclined surface 331 from the inside to the curved surface ( 332) is a bidirectional wedge.

Referring to FIG. 5D, the light guide plate 300 has one side 310 and the other side 320 facing the one side 310, and the rear surface 330 of the light guide plate 300 is one side 310. A first plane 333 formed at the bottom of the first plane, a first inclined plane 331 connected to the first plane 333 and inclined upward inward, and a second plane 334 formed at the bottom of the other side 320. ) And a second inclined surface 332 which is connected to the second plane 334 and inclined upwardly so that one end thereof is engaged with one end of the first inclined surface 331.

Referring to FIG. 5E, the light guide plate 300 has one side 310 and the other side 320 facing the one side 310, and the rear surface 330 of the light guide plate 300 is one side 310. A first plane 333 formed at the bottom of the first plane, a first inclined plane 331 connected to the first plane 333 and inclined upward inward, and a second plane 334 formed at the bottom of the other side 320. ) And a second inclined surface 332 which is connected to the second flat surface 334 and is inclined upwardly so that one end of the first inclined surface is interlocked with one end of the first inclined surface 331.

At this time, in the wedge shapes shown in FIGS. 5A to 5E, the brightness of the back surface itself is better than that of the plane of FIG. 5A, whereas it is difficult to form a pattern by printing. It is good to form. However, in the case of a small light guide plate, the pattern can be formed by both printing and non-printing.

In addition, in the bidirectional wedge shapes as shown in Figs. 5b to 5e, the brightness is further increased than in the one-way wedge shape as shown in Fig. 5a, and as shown in Fig. 5c or Fig. Even in the center farther away from the optical brightness is further increased.

6A and 6B are schematic views illustrating a light guide plate having a curved back surface according to the present invention.

Referring to FIG. 6A, the light guide plate 300 has one side 310 and the other side 320 facing the one side 310, and the rear surface 330 of the light guide plate 300 is one side 310. Cross section is formed as a curved surface 335 made of an arc of a circle so as to connect from the bottom of the bottom to the bottom of the other side (320).

Referring to FIG. 6B, the light guide plate 300 has one side 310 and the other side 320 facing the one side 310, and the rear surface 330 of the light guide plate 300 is one side 310. The first plane 333 formed at the bottom of the second plane, the second plane 334 formed at the bottom of the other side 320, and the first plane 333 connected to the second plane 334. The curved surface 335 is formed of an arc of.

At this time, the curved light guide plate 300 can easily increase the luminance of the center even in the large light guide plate 300 by the optical characteristics of the curved surface 335 itself, it can be applied to both printing or non-printing when forming the pattern. . Therefore, with the increase in the brightness of the shape of the light guide plate 300 itself, a high area ratio is achieved by the combination of the main scattering reflection pattern and the sub-scattering reflection pattern, thereby obtaining the optimum light and thin high brightness light guide plate 300.

As described above, according to the present invention, by forming the main scattering reflection pattern and the sub-scattering reflection pattern of various shapes, it is possible to induce higher quality of the light guide plate of the surface light source device by making the area ratio higher, thereby making the distribution of light brightness uniform. have.

In addition, by controlling the fine light intensity with a sub-scattered reflection pattern, it is possible to reduce the time loss due to the pattern modification of the dark areas, and to eliminate the moire phenomenon for a specific pattern, it is possible to reduce the economic loss since no diffusion sheet is required. It can contribute to the industrial development of medium and large scale surface light source devices.

The present invention is not limited to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical spirit of the present invention.

Claims (16)

A light guide plate having a back surface on which light is scattered and reflected, A main scattering reflection pattern comprising first patterns spaced apart from each other on the rear surface, and a subscattering reflection pattern consisting of second patterns formed in a region between the first patterns adjacent to each of the first patterns A light guide plate of a surface light source device having a. The light guide plate of claim 1, wherein the main scattering reflection pattern or the subscattering reflection pattern is linear, circular, or polygonal. The light guide plate of claim 1, wherein the first pattern or the second pattern is formed to be concave or convex with respect to the rear surface. The light guide plate of claim 3, wherein the first pattern or the second pattern has a cross section of a linear, circular or polygonal shape. The light guide plate of claim 1, wherein the first pattern or the second pattern is formed by printing a dot on the rear surface. The light guide plate of claim 5, wherein the first pattern or the second pattern is linear, circular or polygonal. The light guide plate of the surface light source device according to claim 4 or 6, wherein a diameter of the circular first pattern is 30 µm to 1500 µm. The light guide plate of claim 1, wherein an area of the sub-scattered reflection patterns is 1 to 20% of an area of the main scattered reflection patterns. The light guide plate of the surface light source device according to claim 1, wherein the rear surface of the light guide plate is a flat surface. The light guide plate of claim 1, wherein the light guide plate has one side surface and the other side surface facing the one side surface and having a height lower than the height of the one side surface, wherein the rear surface of the light guide plate has the other side surface from the bottom of the one side surface. The light guide plate of the surface light source device characterized by the one-way wedge-shaped which consists of the inclined surface which connects the bottom part. The light guide plate of claim 1, wherein the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate has a first inclined surface inclined upwardly from the bottom of the one side surface, and one end thereof. The light guide plate of the surface light source device characterized in that it is a bidirectional wedge-shaped consisting of a second inclined surface inclined upward from the bottom of the other side so as to occlude one end of the first inclined surface. The light guide plate of claim 1, wherein the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate has a first inclined surface inclined upwardly from the bottom of the one side surface, and one end thereof. The light guide plate of the surface light source device characterized in that it is a bi-directional wedge-shaped consisting of a second inclined surface inclined upward from the bottom of the other side surface so that one end of the first inclined surface and the inside of the curved surface. The light guide plate of claim 1, wherein the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate is connected to a first plane formed at a bottom of the one side surface, and to the first plane. A first inclined surface inclined upwardly to the inside, a second plane formed at the bottom of the other side, and one end of the first inclined surface to be connected to the second plane so as to be mated at one end of the first inclined surface and inclined upwardly The light guide plate of the surface light source device characterized by the bidirectional wedge-shaped which consists of a 2nd inclined surface. The light guide plate of claim 1, wherein the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate is connected to a first plane formed at a bottom of the one side surface, and to the first plane. A first inclined surface inclined upwardly to the inside, a second plane formed at the bottom of the other side, and one end thereof is connected to the second plane so that one end of the first inclined surface interlocks from the inside to the curved surface and is upward The light guide plate of the surface light source device characterized by the bidirectional wedge shape which consists of an inclined 2nd inclined surface. The light guide plate of claim 1, wherein the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate is connected to an arc of a circle so that the cross section is connected from the bottom of the one side to the bottom of the other side. The light guide plate of the surface light source device characterized by the curved surface formed. The light guide plate of claim 1, wherein the light guide plate has one side surface and the other side surface facing the one side surface, and the rear surface of the light guide plate is formed on a first plane formed at a bottom of the one side surface, and at a bottom of the other side surface. A light guide plate of a surface light source device, characterized in that the cross section is a curved surface formed by an arc of a circle so as to be connected to the second plane to be formed and the first plane and the second plane.