KR101077993B1 - Preparing of light guide plate by extruding engraving - Google Patents

Abstract

The present invention provides a light guide plate provided in a backlight unit by extrusion engraving method, and more particularly, in a method of manufacturing a light guide plate, a melt extrusion step of melt-extrusion of a polymer resin onto a plate; A stamping step of forming the extruded plate, the reflective pattern being formed on the upper surface of the unit structure and the lower surface by the pattern roll; And relates to a light guide plate manufacturing method by an extrusion stamping method comprising a cooling step of cooling the stamped plate.

Extrusion, light guide plate, reflective pattern, rounding, square pyramid, high brightness

Description

Light guide plate manufacturing method by extrusion engraving method {Preparing of light guide plate by extruding engraving}

The present invention relates to a light guide plate of a backlight unit, and more particularly, to a manufacturing method of a light guide plate by an extrusion stamping method having high light collecting efficiency and excellent visibility.

Recently, various flat panel display devices have been developed. These flat panel display devices include liquid crystal displays (LCDs), plasma display panels (PDPs), and field emission displays (FEDs). In addition, studies are being actively conducted to improve the display quality of such flat panel displays.

Among them, LCD is a device that injects liquid crystal between two sheets of glass and applies power to the electrodes installed on the upper and lower glass plates to change the arrangement of liquid crystal molecules and display images in each pixel. Such an LCD display device is usually composed of an LCD panel unit, a driver, and a backlight unit. The LCD panel does not emit light by itself and has only a function of transmitting light on the rear surface. Therefore, in the absence of light, that is, at night or indoors, it is a structure that can not display images without the help of backlight. The backlight unit refers to a system for implementing the backlight of such an LCD.

The backlight unit is largely composed of a lamp, sheets, a mechanism part, and a driving circuit. Since the lamp alone cannot produce uniform light over the entire area, the light guide plate, diffuser plate, reflector plate, prism, frame, etc., sheets and mechanisms are provided.

The backlight unit includes a mold frame having a storage space formed thereon and a reflective sheet reflecting light toward the liquid crystal display panel, a light guide plate installed on an upper surface of the reflective sheet for guiding light, and the light guide plate and the storage space have sidewalls. A lamp unit installed between the light emitting plates, an optical sheet stacked on the upper surface of the light guide plate to diffuse and collect light, and an upper portion of the mold frame, which extends from the predetermined position of the edge of the liquid crystal display panel to the side of the mold frame. It consists of a covering top chassis.

On the other hand, the light guide plate guides the light emitted from the lamp to reach the entire light guide plate plane to have a uniform luminance distribution, and at the same time reflects it to the front surface to change the linear light source of the lamp into a surface light source in the form of a plane. In order to increase the uniform luminance distribution and luminance of the optical function film such as reflective film, diffuser film, prism film is used.

The light guide plate may not have a uniform distribution on the entire surface of the light guide plate by itself. Therefore, there is a method of printing or grooving the light guide plate surface with white ink, and the light is scattered by the printed ink or the grooves, and a similar amount of light is emitted through the light guide plate surface.

The light guide plate may be classified according to a shape or a light emitting method, and may be divided into a flat plate type and a wedge type depending on the shape. Flat panel type is mainly used for monitor and is formed by extrusion, injection or casting method and it is a structure where light is incident in both directions. In some cases, one to three CCFLs can be used in a single direction to cope with high brightness. It is common to use a light guide plate with a thickness of 3 to 6 mm when one CCFL is used, and a thickness of 6 to 8 mm when two are used, and a 10 to 12 mm thickness when three are used.

The wedge method has better light efficiency and is thinner than the flat plate method, and is mainly used for mobile display (notebook PC, PDA, etc.) that uses light weight parts, and it is molded by injection or casting method. This incident structure is used up to 16 inches.

In addition, according to the light emission method, the reflection pattern can be divided into a printing method and a non-printing method according to the method of emitting light in the vertical direction of the light guide plate so that the light of the incident light source has a uniform light intensity distribution on the front surface. In this case, the light scattering ink is screen-printed on the lower part of the light guide plate to emit light through the vertical scattering of the incident light.

In the case of the non-printing method, a structure having a geometric optical function (reflection, refraction, diffraction, scattering) is processed on the light guide plate to have a light output function through the structure, and a material capable of scattering light inside the transparent resin. There is a molding method that mixes light output and develops various methods for each company.

The mass production stability of the injection itself falls with the increase in the size of the light guide plate. Therefore, the printing method is mainly used in the small size of 6 inches or less, and the printing method is used in the size of 12.1 inches or more. It has advantages in mass production yield and light efficiency.

Among them, the printing light guide plate is the most commonly used form of light intensity distribution (uniformity) control among the light guide plates, and PVA (Polyvinyl--) is used to increase the adhesive strength by using PMMA as the main material on the Bare light guide plate formed by injection or casting method. alchol) is added and dissolved in an organic solvent, and then the ink mixed with the light scattering agent is screen printed to form a reflective pattern.

The light guide plate manufactured by the above method is a light emitted from the light source on the side of the light guide plate is reflected near the upper and lower edges of the light incident portion of the light guide plate, so that a bright line and a dark line appear alternately in the light guide plate incident region and light is generated. There is a problem that a dark portion occurs on the side of the light guide plate which is not incident.

In addition, there is a problem that it takes a long time until the product is completed by a separate manufacturing process of the reflective pattern, whether the non-printing method or printing method, and in the case of manufacturing the light guide plate by injection molding which is a general manufacturing method of the light guide plate There is a drawback in that it takes a long time to mass production.

Therefore, it is desired to develop a light guide plate which does not generate bright lines and dark lines, and has high brightness, excellent light uniformity and visibility, and a light guide plate having improved production efficiency by treating it as one step in production.

An object of the present invention to solve the above problems is to provide a manufacturing method that can improve the production efficiency in producing a light guide plate.

Another object of the present invention is to provide a method of manufacturing a light guide plate having a high light collecting effect.

Still another object of the present invention is to provide a method of manufacturing a light guide plate having improved physical properties such as transparency, cloudiness, and luminance.

Still another object of the present invention is to provide a method of manufacturing a light guide plate having no bright and dark lines and excellent light uniformity and visibility.

In order to solve the above problems, the present invention provides a method of manufacturing a light guide plate, comprising: a melt extrusion step of melt extruding a polymer resin onto a plate; A stamping step of forming the extruded plate, the reflective pattern being formed on the upper surface of the unit structure and the lower surface by the pattern roll; And it provides a light guide plate manufacturing method by extrusion stamping method comprising a cooling step of cooling the stamped plate.

In addition, the present invention is indented to include a plurality of unit structures protruding embossed in the upper surface of the light guide plate in the engraving step, the unit structure is a rectangular pyramid shape rounded corners of the protruding portion curved, the upper portion of the unit structure It provides a light guide plate manufacturing method by extrusion extrusion method characterized in that the rounded by a curve.

In another aspect, the present invention provides a method for manufacturing a light guide plate by extrusion extrusion method, characterized in that the length (L) of the bottom surface of the unit structure is 50 to 200㎛.

In another aspect, the present invention provides a method for manufacturing a light guide plate by extrusion extrusion method, characterized in that the height (H) of the unit structure is 10 to 150㎛.

In another aspect, the present invention provides a light guide plate manufacturing method according to the extrusion stamping method, characterized in that the separation distance of each unit structure in the plurality of unit structures is 0 to 100㎛.

In another aspect, the present invention provides a light guide plate manufacturing method according to the extrusion stamping method characterized in that the reflection pattern is formed in an intaglio, the area is 0.01 to 1mm2.

In another aspect, the present invention provides a light guide plate manufacturing method by extrusion extrusion method, characterized in that the interval between the reflection pattern is 0.5 to 5mm.

In another aspect, the present invention provides a method of manufacturing a light guide plate by the extrusion engraving method, characterized in that the reflective pattern is a prism shape.

In another aspect, the present invention provides a light guide plate manufacturing method according to the extrusion stamping method characterized in that the densities of the reflection pattern is farther away from the light source, the fill factor is 20 to 90%.

In another aspect, the present invention provides a method of manufacturing a light guide plate by extrusion extrusion method wherein the cooling step is quenched, consisting of 4 to 20 ℃ cooling air.

The light guide plate manufacturing method according to the extrusion stamping method according to the present invention has the effect of improving the production efficiency by treating in one step.

The light guide plate manufactured by the extrusion engraving method according to the present invention has a good light collecting efficiency, and has an effect of improving various physical properties such as transparency, cloudiness, and brightness.

The light guide plate manufactured by the extrusion engraving method according to the present invention does not generate bright lines and dark lines and has excellent light uniformity and visibility.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that in the drawings, the same components or parts denote the same reference numerals as much as possible. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

As used herein, the terms “about”, “substantially”, and the like, are used at, or in close proximity to, numerical values when manufacturing and material tolerances inherent in the meanings indicated are intended to aid the understanding of the invention. Accurate or absolute figures are used to assist in the prevention of unfair use by unscrupulous infringers.

Figure 1 shows a manufacturing process of the light guide plate by the melt extrusion extrusion method according to an embodiment of the present invention.

In the method of manufacturing a light guide plate according to an embodiment of the present invention, the melt extrusion step of melt-extruding a polymer resin on a plate (plate); A stamping step of forming the extruded plate, the reflective pattern being formed on the upper surface of the unit structure and the lower surface by the pattern roll; And it characterized in that the light guide plate by extrusion stamping comprising a cooling step of cooling the stamped plate.

The present invention provides a light extrusion plate of the melt extrusion stamping method, referring to Figure 1, the polymer resin is melt-extruded from the T-die 110. The polymer resin is not particularly limited, but PMMA or PC is generally used as a material of the light guide plate. The polymer resin has good flowability, is convenient to control the residual stress, and melted at a temperature capable of producing a desired phosphorus shape at the time of extrusion, and is extruded through the T-die.

The extruded polymer resin passes through the pattern rolls. Looking at the pattern rolls 120 and 130, the first engraving pattern 121 has a shape that can give a shape to the upper surface of the light guide plate. The reflective pattern of the lower surface of the light guide plate may be provided through the second engraving pattern 131 of the second pattern roll 130.

Therefore, the shape of the light guide plate is determined according to the state and shape of the relief patterns 121 and 131. As such, in the case of forming the reflective pattern, the light guide plate was manufactured according to a melt extrusion method different from the conventional method.

The first pattern roll and the second pattern roll speed is preferably 15 to 25 m / min of the speed of the engraving patterns 121 and 131 in the first pattern roll and the second pattern roll in the engraving step.

As the polymer resin is extruded through the T-die, the polymer resin passes through the first pattern roll 120 and the second pattern roll 130 to give a shape of the upper surface of the light guide plate to the first engraving pattern 121 of the first pattern roll 120. The reflection pattern applied to the lower surface of the light guide plate is applied to the second engraving pattern 131 of the pattern roll 130 (area A).

In the light guide plate manufactured according to the exemplary embodiment of the present invention, the upper surface of the light guide plate includes a plurality of unit structures protruding with an embossment, and the lower surface includes a negative reflection pattern, and the unit structure protrudes as a polygonal pyramid shape. A corner of the part is rounded in a curve, and the upper part of the unit structure is rounded in a curve.

In the present specification, the unit structure is described as an example of a quadrangular pyramid protruding portion in the shape of a pyramid, but is not limited thereto. The unit structure may also be applied without limitation to triangular pyramids, pentagonal pyramids, and polygonal pyramids.

Figure 2 shows a perspective view of a light guide plate manufactured according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line X and X 'of FIG. 2, and FIG. 4 is a cross-sectional view of the unit structure protruding in relief.

In FIG. 2, the protrusion of the unit structure 210 forms a square pyramid shape, the corners round the curves, and the top of the unit structure rounds the curve. That is, the bottom surface of the protrusion of the unit structure 210 forms a quadrangular rounded corner, preferably a rounded square. That is, the cross section in the horizontal direction in the quadrangular pyramid shape is a quadrangular shape with four angles rounded (see FIG. 4), and the vertical cross section (see FIG. 3) consists of a triangular shape 211 with a rounded upper portion, so that not only the characteristics of high brightness but also diffusion are obtained. The effect is excellent.

The protruding unit structure 210 serves to diffuse and condense the incoming light. The light condensed or diffused by the unit structure 210 moves in the direction of the liquid crystal display panel, and the reflected light is used to reflect the reflective sheet. It is reflected back through to focus or diffuse through the unit structure.

In addition, if the shape of the unit structure 210 forms a triangular pyramid shape and rounded corners and the upper portion, the bottom surface of the protrusion of the unit structure 210 is a four-rounded triangular shape, the longitudinal cross section of the unit structure 210 The upper portion will have a rounded triangular shape, and in the case of other polygonal pyramid shapes, the bottom surface will have a polygonal shape with rounded angles.

On the other hand, the unit structure 210 has a predetermined curvature when four angles are rounded in the cross section of the transverse direction, the size of the four radius of curvature (R1) shown in Figure 4 is preferably all the same. In addition, even in the case of the triangular shape 211 rounded at the upper end in the longitudinal section (see FIG. 3), it is a matter of course that the radius of curvature R is given.

Next, the length of the bottom of the unit structure 210, if the maximum length in the figure representing the bottom of the protrusion is the length of the bottom of the unit structure in the case of Figure 5 the line connecting the diagonal will be the maximum length, It is preferable that the length L of the bottom surface of a unit structure is 50-200 micrometers.

In addition, the height of the unit structure according to an embodiment of the present invention may be represented by a triangular height (H) rounded at the top in Figure 3, the height (H) of the unit structure is preferably 10 to 150㎛. .

In addition, although the unit structure 210 has a plurality of light guide plates 200, the unit structure 210 preferably has the same shape.

In addition, the plurality of unit structures 210 may be formed at an arbitrary distance or in close contact with each other. It is preferable that the separation distance of each unit structure is 0-100 micrometers. However, the separation distance is preferably less than 1/2 times the length L of the bottom surface of the unit structure. For example, when the length of the bottom surface is 100㎛, it is preferable that the separation distance of the unit structure is formed to 50㎛ or less.

On the other hand, the light guide plate 200 may further include light diffusing particles when the polymer resin is melted. Since the light diffusing particles have good compatibility with the polymer resin including the particles, organic particles having a similar refractive index to the material and the refractive index are Low spherical silicon particles were examined and used, and inorganic particles with a refractive index of 1.50-1.80 can be used. Particularly, the particle selection to be used is advantageous for solving the problem such as showing the bright line because the spherical particles having a refractive index difference of 0.1 to 0.2 from the material increases shielding properties and can maximize the diffusion effect with a relatively small particle amount. It is very advantageous because it can.

The refractive index of the diffusing agent particles used increases the light diffusion effect as the difference between the material and the refractive index is larger, but when the refractive index difference is too large, it is disadvantageous in terms of increasing the brightness, so that the proper refractive index difference is obtained and sometimes similar to the material. It is preferable to use the particle | grains with a big difference.

Non-limiting examples of light diffusing particles that can be used in the present invention include methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid, Hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, acrylamide, metalolacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate and 2 Homopolymers, copolymers or terpolymers of monomers selected from ethylhexyl acrylate, beads made from copolymers of polyethylene, polystyrene, polypropylene, acrylics and olefins, and silicone-based spherical particles may be used. Preferably, the particles are spherical particles between 0.1 microns and 10 microns having a refractive index difference of about 0.1 to about 0.2. Spherical organic particles having such a difference in refractive index can be easily dispersed in the resin because they have densities similar to those of the material used in the present invention (about 1.10 to 1.30 g / cm 3).

The light diffusing particles used in the present invention may use different ones in type and / or size. For example, light diffusion efficiency can be enhanced by mixing two or more kinds of particles having a difference in refractive index rather than a single type. In addition, light diffusing efficiency may be increased by using particles having similar refractive indices and different sizes, and by applying porous particles, the brightness may be increased while maximizing light diffusing efficiency after assembling the backlight unit. It is preferable to use light-diffusion particle at 0.2-5 weight part with respect to 100 weight part of light guide plates. The diffusion effect is excellent within the above range.

Meanwhile, an intaglio reflective pattern 220 is formed on a bottom surface of the light guide plate manufactured according to the embodiment of the present invention, and the reflective pattern 220 is formed in an intaglio form according to a melt extrusion extrusion method.

The shape of the reflective pattern 220 is preferably an intaglio circular shape, but is not limited thereto. The reflective pattern 220 may be a polygon other than an oval, a triangle, and a rectangle. The area of the reflective pattern 220 is preferably 0.01 to 1 mm 2 and light is well reflected in the emission direction within the above range. The area of the reflective pattern 220 becomes larger as the distance from the light source increases, so that light can be guided well in the light guide plate. In addition, the spacing between the reflective patterns 220 may be adjusted, and the spacing between the reflective patterns 220 is preferably 0.5 to 5 mm.

The reflective pattern 220 may have a prism shape. It is preferable that the longitudinal direction of the prism shape is formed to be perpendicular to the direction in which light is emitted (light emitting part). This is because diffraction, refraction, and diffusion of light occur well when the prism length direction is formed perpendicular to the direction in which light is emitted, and the light can be uniformly refracted and diffused overall.

The density of the reflection pattern 220 becomes denser as it moves away from the light source, thereby compensating for the weakening of the light from the light source, thereby improving reflection and improving the uniformity and visibility of the light.

The density can be applied using a fill factor, and the definition of the fill factor can be easily seen with reference to FIG. 6. When the three reflective patterns 220 are connected to each other to form a triangle, the triangle The ratio represented by the percentage of the reflective pattern area 220 (hatched area in FIG. 6) is shown. That is, "(area of reflective pattern in triangle) ÷ (area of triangle formed by connecting three reflective pattern centers) x 100".

The density of the reflective pattern 220 is preferably designed to be denser as the distance from the light source increases. In this method, the area of the reflective pattern 220 increases as the distance from the light source increases, and the distance between the reflective patterns 220 decreases. There may be a method of increasing the area of the reflective pattern 220 and reducing the pitch.

The density of the reflective pattern 220 becomes denser as it moves away from the light source, and preferably has a fill factor of 20 to 90%.

After the engraving step, the light guide plate is cooled between the first pattern roll 120 and the roller 140, and is cooled between the first pattern roll 120 and the roller 140 (region B) (see FIG. 1). To this end, by forming a quenching condition in the region B to rapidly lower the surface temperature of the light guide plate, and minimizes the possibility of shape change by limiting the flow of the polymer chain due to residual stress as the light guide plate is cured. .

Specifically, a cooling means such as an air knife may be further provided on the surface of the light guide plate on which the inscribed shape is realized, thereby fixing the shape expressed on the light guide plate. At this time, the cooling temperature is preferably 4 to 20 ℃, more preferably 4 to 10 ℃.

Hereinafter, embodiments of the present invention will be described in detail.

Example  One

As the polymer resin, a light guide plate was manufactured using a PMMA resin. The PMMA resin was melt-extruded and then stamped with a pattern roll. The unit structure of the upper surface of the light guide plate at the time of engraving is formed in the shape of a square pyramid of the protruding portion, the corner and the top of the unit structure rounded in a curved shape, the length (L) of the bottom surface of the unit structure is 140㎛, height (H ) Is 70㎛ and the separation distance of the unit structure is placed in close contact with 0㎛ was prepared in a plurality of the same shape. The lower surface of the light guide plate is manufactured by forming a prism-shaped reflection pattern in an intaglio, but the area of the reflection pattern is 1 mm 2, and the distance between the reflection patterns is narrowed away from the light source, and then the surface is cooled and cooled at about 5 ° C. using a cooling means. To prepare a light guide plate.

Example  2

The same procedure as in Example 1, except that the length (L) of the bottom surface of the unit structure is 200㎛, the height (H) is 70㎛, the separation distance of the unit structure is 5㎛ unit structure consisting of a plurality of the same shape To form a light guide plate.

Example  3 and 4

The light guide plate was manufactured in the same manner as in Examples 1 and 2, but blending isobutyl methacrylate as 2 parts by weight with respect to 100 parts by weight of the polymer resin as the light diffusing agent.

Comparative example  One

The light guide plate was manufactured in the same manner as in Example 1, without forming a unit structure on the upper surface.

Comparative example  2

A light guide plate was manufactured in the same manner as in Example 1 except that the unit structure had a hemispherical lens shape having a diameter of 50 μm and the separation distance between the unit structures was 5 μm.

Comparative example  3 and 4

Comparative Examples 1 and 2 were carried out in the same manner, but a light guide plate was prepared by blending ethyl methacrylate as 10 parts by weight with respect to 100 parts by weight of the polymer resin as a light diffusing agent.

* Test Methods

1. Transmittance (TT) and haze (Haze): Measured by ASTM D1003 method using NIPPON DENSHOKU 300A analyzer.

2. Luminance: Measured on a stage equipped with a manufactured light guide plate on a backlight unit, and equipped with TOPCON BM-7 under CCFL voltage of 16.5V and dimming value of 2.8V.

3. Uniformity

The manufactured light guide plate is mounted on a backlight unit (light guide plate-diffusion film-prism-diffusion film), and the voltage of CCFL is measured on a stage equipped with TOPCON BM-7 under a condition of 16.5V and dimming value of 2.8V, and a liquid crystal display device. Measure the average degree of the luminance (L) [(L _min / L _max ) X100] measured at nine points evenly distributed throughout the panel.

Table 1 below is a result of testing the optical properties of the light guide plate manufactured in each of the Examples and Comparative Examples regarding the transmittance, brightness, and the like.

division Transmittance (%) Cloudiness (%) Brightness (cd / m 2) Uniformity (%) Example 1 63 89.6 10140 91.5 Example 2 64 89.2 10170 91.6 Example 3 65 88.1 10030 91.9 Example 4 64 88.4 10050 91.7 Comparative Example 1 62 88.1 9680 86.3 Comparative Example 2 63 87.2 9840 86.1 Comparative Example 3 63 88.4 9620 87.3 Comparative Example 4 65 89.2 9690 87.1

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge of.

Figure 1 shows a schematic view of the manufacturing process of the light guide plate by the extrusion stamping method according to an embodiment of the present invention.

Figure 2 shows a perspective view of a light guide plate manufactured according to an embodiment of the present invention.

3 is a cross-sectional view taken along line X and X ′ of FIG. 1.

FIG. 4 is a cross-sectional view of the unit structure protruding embossed from the light guide plate manufactured according to the embodiment of the present invention.

5 illustrates the shape of the bottom surface of the unit structure in the light guide plate manufactured according to the embodiment of the present invention.

FIG. 6 is a view for explaining the concept of a fill factor.

Claims (10)

In the manufacturing method of the light guide plate, A melt extrusion step of melt extruding the polymer resin onto a plate; A stamping step of forming the extruded plate, the reflective pattern being formed on the upper surface of the unit structure and the lower surface by the pattern roll; And Including a cooling step of cooling the stamped plate, The reflective pattern is formed in an intaglio, and the density of the reflective pattern becomes denser as the distance from the light source, the fill factor is 20 to 90%, the light guide plate manufacturing method by the extrusion stamp method. . The method of claim 1, In the engraving step, the upper surface of the light guide plate is inscribed to include a plurality of unit structures protruding in relief, The unit structure has a rectangular pyramid shape, the corners of the protruding portion is rounded in a curve, the upper portion of the unit structure is a light guide plate manufacturing method according to the extrusion stamping method characterized in that the rounded. 3. The method of claim 2, The length (L) of the bottom surface of the unit structure is 50 to 200㎛ method of manufacturing a light guide plate by the extrusion engraving method. 3. The method of claim 2, The height (H) of the unit structure is a light guide plate manufacturing method by extrusion extrusion method, characterized in that 10 to 150㎛. 3. The method of claim 2, The distance of each unit structure in the plurality of unit structures is a light guide plate manufacturing method by extrusion extrusion method, characterized in that 0 to 100㎛. The method according to claim 1 or 2, The area of the reflective pattern is a light guide plate manufacturing method by an extrusion stamp method, characterized in that 0.01 to 1mm2. The method according to claim 1 or 2, The light guide plate manufacturing method according to the extrusion stamping method, characterized in that the interval between the reflective pattern is 0.5 to 5mm. The method according to claim 1 or 2, The reflective pattern is a light guide plate manufacturing method by the extrusion engraving method, characterized in that the prism shape. delete The method of claim 1, The cooling step is a quenching, light guide plate manufacturing method according to the extrusion stamping method consisting of 4 to 20 ℃ cooling air.

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