KR20100085610A - Apparatus for manufacturing pattern on light guide plate using laser, method for manufacturing pattern on light guide plate using laser and light guide plate - Google Patents

Abstract

PURPOSE: A laser pattern processing device, a laser pattern processing method, and a light guide plate are provided to reduce the pattern processing time of the light guide plate by processing a pattern to one curve. CONSTITUTION: A laser oscillator(110) generates a laser beam. A substrate support unit(120) supports the processing object light guide plate. A laser head(130) irradiates the laser beam inputted from the laser oscillator to the light guide plate. The laser head moves straight according to the processing surface of the light guide plate. A rotation driving unit rotates the substrate support unit with a rotation axis passing through the central part(121) of the substrate support unit as the center.

Description

Apparatus for manufacturing pattern on light guide plate using laser, Method for manufacturing pattern on light guide plate using laser and Light guide plate}

The present invention relates to a laser pattern processing apparatus, a laser pattern processing method and a light guide plate, and more particularly, a laser pattern processing apparatus, a laser pattern processing method and a spiral pattern on which a spiral pattern can be processed on a light guide plate. It relates to a light guide plate.

In general, a backlight unit used in a liquid crystal display (LCD) processes one surface of the light guide plate into a predetermined pattern because it is preferable to uniformly scatter the emitted light to form a uniform brightness on the light guide plate. Manufacturing methods applied for optical pattern formation on the light guide plate include screen printing, mold processing, V-cutting, and the like.

Screen printing has a long history of stability, but the process is complicated and causes many defects in the printing process. The mold processing method is a method of directly injecting a light guide plate by manufacturing a shape having a light scattering function, but it is suitable for mass production, but there are many defects due to thermal deformation of the light guide plate, and an increase in the cost and duration of mold manufacturing is disadvantageous. In addition, when the pattern design is changed, the mold cannot be easily modified and the reproducibility of the pattern shape is deteriorated. The V-cutting method is a method of forming a V-shaped groove pattern using a diamond tool on the surface of the light guide plate. When the model is changed, the V-cutting method can shorten the time required for design and development of patterns, molds, and stampers. However, there is a disadvantage in that the processing time is long and light is not uniformly scattered due to the roughness of the processing surface.

Recently, a method of forming a pattern on a light guide plate using a laser is widely used, but FIG. 1 is a view showing an example of a conventional laser pattern processing apparatus. As shown in FIG. 1, in the conventional laser pattern processing apparatus 1, a light guide plate W is placed on a table 11, and a laser oscillator 12 is disposed above the table 11. The laser beam emitted from the laser oscillator 12 is incident to the laser head 16, and the laser beam incident to the laser head 16 is irradiated to the light guide plate W. An X-axis driving unit 13 for linearly moving the laser head 16 in the X-axis direction and a Y-axis driving unit 14 for linearly moving the laser head 16 in the Y-axis direction are provided on the light guide plate W. The linear pattern in the X-axis direction or the Y-axis direction is processed.

In the conventional laser pattern processing apparatus, the laser head is linearly reciprocated many times in order to process a plurality of linear patterns. Therefore, there is a problem in that the time for processing the pattern in one light guide plate is long.

An object of the present invention is to solve such a conventional problem, the laser beam by processing the pattern on the light guide plate while rotating the light guide plate itself while moving a single number of times linearly from the center of the light guide plate to the edge portion, significantly reducing the pattern processing time of the light guide plate The present invention provides a laser pattern processing apparatus, a laser pattern processing method, and a light guide plate.

In order to achieve the above object, the laser pattern processing apparatus of the present invention includes a laser pattern processing apparatus for forming a pattern on a light guide plate using a laser beam, the laser oscillator for generating a laser beam; A substrate support for supporting a light guide plate to be processed; A laser head that irradiates a laser beam incident from the laser oscillator to the light guide plate, and linearly moves along a processing surface of the light guide plate; And a rotation driving unit configured to rotate the substrate support with the rotation axis penetrating through the central portion of the substrate support.

In addition, in order to achieve the above object, the laser pattern processing method of the present invention, in the laser pattern processing method for forming a pattern on the light guide plate using a laser beam, the rotation axis passing through the center of the light guide plate as the rotation center Rotating the light guide plate; Irradiating a laser beam to the light guide plate while the light guide plate is rotating, linearly moving the laser beam from the center of the light guide plate to the edge of the light guide plate or from the edge of the light guide plate to the center of the light guide plate. It is done.

In addition, in order to achieve the above object, the light guide plate of the present invention, in the light guide plate used in the backlight unit, is processed with a laser beam, and the spiral pattern is distributed so as to diffuse and scatter light with uniform illuminance at each site. And a central portion thereof coincides with a central portion of the spiral pattern.

According to the laser pattern processing apparatus, the laser pattern processing method, and the light guide plate of the present invention, the pattern processing time of the light guide plate can be reduced by processing the pattern with one curve without processing the pattern with a plurality of straight lines.

In addition, according to the laser pattern processing apparatus, the laser pattern processing method, and the light guide plate of the present invention, since the depth of the processing cross section is deep at the center of the light guide plate and the depth of the processing cross section is shallow at the edge of the light guide plate, high light efficiency is required at the center of the light guide plate. It can satisfy the quality requirements of the light guide plate.

In addition, according to the laser pattern processing apparatus, the laser pattern processing method and the light guide plate of the present invention, the pattern is processed by making the angle between the optical axis of the laser beam and the light guide plate at an acute angle rather than vertical, thereby comparing the roughness of the edge of the light guide plate to the center of the light guide plate. The illuminance of can be obtained relatively high.

Hereinafter, embodiments of the laser pattern processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a perspective view of a first embodiment of the laser pattern processing apparatus of the present invention, FIG. 3 is a sectional view of a light guide plate processed by the laser pattern processing apparatus of FIG. 2, and FIG. 4 is a laser head of the laser pattern processing apparatus of FIG. 5 is a front view of the laser head of FIG. 4, FIG. 6 is a view illustrating a state in which the reflecting mirror and the condenser lens of the laser head of FIG. 4 are rotated at an angle in the position shown in FIG. 4, and FIG. 7. 6 is a cross-sectional view of the light guide plate processed by the reflective mirror and the condenser lens of FIG. 6, and FIG. 8 is an enlarged view of a portion “A” of the laser pattern processing apparatus of FIG. 2, and is a perspective view of the light guide plate alignment unit, and FIG. 9 is FIG. It is a perspective view of the rotation drive part of the laser pattern processing apparatus of this invention.

2 to 9, the laser pattern processing apparatus 100 according to the present embodiment is capable of processing a spiral pattern on a light guide plate, and includes a laser oscillator 110, a substrate support part 120, and a laser. The head 130, the rotation driving unit 140, and the light guide plate alignment unit 150 are included.

The laser oscillator 110 is mainly a CO2 laser oscillator for generating a laser beam of an infrared (red) wavelength to be suitable for the processing of the light guide plate (W) made of a PMMA material. The laser beam L generated from the laser oscillator 110 may be a continuous wave laser beam or a pulsed laser beam, but is preferably a continuous wave laser beam.

The substrate support part 120 supports the light guide plate W to be processed. A through hole is formed on a surface of the substrate support part 120 in contact with the light guide plate W. A vacuum pressure is formed through the through hole, so that the light guide plate W may be absorbed and fixed.

The laser head 130 irradiates the laser beam L incident from the laser oscillator 110 toward the light guide plate W, and includes a reflection mirror 131 and a condenser lens 133.

The reflection mirror 131 changes the direction of the laser beam L so as to irradiate the processing surface of the light guide plate W placed on the lower side. As shown in FIGS. 5 and 6, an angle θ1 formed between the optical axis L1 of the laser beam reflected by the reflecting mirror 131 and irradiated to the light guide plate W and the processing surface of the light guide plate W The reflection mirror 131 is rotatably installed so that can be changed. A plate fixing the reflective mirror 131 may be coupled to a rotating shaft of a motor (not shown) to rotate the reflective mirror 131.

As the reflection mirror 131 is rotated to form an angle between the optical axis L1 of the laser beam and the light guide plate W at an acute angle, the laser beam L is incident perpendicularly to the light guide plate W as shown in FIG. 6. Compared with the cross section of the pattern in the case, the cross section of the pattern is processed to have a lower inclination angle toward the edge of the light guide plate W. As shown in FIG. Typically, a reflecting film having a reflectance of about 99.9% is coated on the surface of the reflecting mirror 131 to which the laser beam L is incident.

The condenser lens 133 is installed below the reflective mirror 131 to collect the laser beam L reflected by the reflective mirror 131 and irradiate the light guide plate W. The condenser lens 133 may also be rotatably installed like the reflective mirror 131 and may be connected to a rotating motor (not shown) to rotate. As shown in FIG. 6, when the reflective mirror 131 rotates at an angle, the laser beam L reflected by the reflective mirror 131 may be incident perpendicularly to the incident surface of the condenser lens 133. The condenser lens 133 is rotated synchronously with the reflective mirror 131.

The laser head 130 may be mounted on the linear driver 160 to linearly move along the processing surface of the light guide plate W. FIG. The linear driving unit 160 may be implemented by a combination of a linear motor and a linear guide rail, or may be implemented by a combination of a rotary motor, a roller, a belt and a linear guide rail, or a rotary motor, a ball screw, a straight line It may also be implemented by a combination of motion guide rails and the like. Since the configuration of the linear drive unit is well known to those skilled in the art, further detailed description thereof will be omitted.

The rotation driving part 140 is installed below the substrate support part 120 to rotate the substrate support part 120 using the rotation axis C passing through the center of the substrate support part 120 as the rotation center. The rotation driving unit 140 includes a motor 141, a driving roller 143 fixed to the output shaft of the motor 141, a driven roller 145 fixed to the rotation shaft C of the substrate support unit 120, and a driving roller. 143 and a belt 147 wound around the driven roller 145. The rotation driving unit 140 may be implemented as a combination that engages the driving gear and the driven gear without using a belt, and may also directly connect the rotating shaft C of the motor 141 and the substrate support 120. It may be implemented in the form.

The light guide plate alignment unit 150 includes a substrate support part such that the center W1 of the light guide plate and the center part 121 of the substrate support part coincide with each other in order to rotate the light guide plate W and the substrate support part 120 at the same rotation axis. The light guide plate W placed on the 120 is aligned. The light guide plate alignment unit 150 includes a contact member 151 contacting or spaced from the edge portion W2 of the light guide plate W, and a pneumatic cylinder to which the contact member 151 is fixed and linearly reciprocates the contact member 151. 153). When the light guide plate W is placed on the substrate support 120, the rod of the pneumatic cylinder 153 is advanced and the light guide plate W is not in contact with the contact member 151, but the light guide plate W is connected to the substrate support 120. ), The rod of the pneumatic cylinder 153 retreats to contact each edge portion W2 of the light guide plate W and the contact member 151 to contact the center portion W1 of the light guide plate and the center portion 121 of the substrate support portion. The light guide plate W is aligned so that.

FIG. 10 is a plan view of a first embodiment of a light guide plate of the present invention, FIG. 11 is a plan view of a second embodiment of a light guide plate of the present invention, FIG. 12 is a view showing a traveling path of light in the light guide plate of FIG. 7 is a view showing a path of light traveling in the light guide plate of FIG. 7, and FIGS. 14 and 15 are views for explaining a second embodiment of the laser pattern processing method of the present invention.

Hereinafter, the laser pattern processing method of the present invention for processing a spiral pattern on the light guide plate using the above-described laser pattern processing apparatus will be described with reference to FIGS. 2 to 14.

First, in the embodiments of the laser pattern processing method of the present invention, a first embodiment in which a spiral pattern is processed in a circular shape as a whole will be described.

The light guide plate W is seated on the substrate support part 120 to align the light guide plate W so that the center part W1 of the light guide plate and the center part 121 of the substrate support part coincide with each other. The light guide plate W is rotated with C) as the center of rotation. At this time, while the light guide plate W rotates, the rotational angular velocity of the light guide plate W is constantly maintained through the rotation driving unit 140.

Thereafter, while irradiating the laser beam L to the light guide plate W while the light guide plate W rotates, the laser beam L is linearly moved from the central portion W1 of the light guide plate to the edge portion W2 of the light guide plate. The laser head 130 is moved at a constant speed from the central portion W1 of the light guide plate to the edge portion W2 of the light guide plate through the linear driver 160.

For example, while the light guide plate W rotates at a rotational angular speed of about 300 RPM, the laser head 130 moves from the central portion W1 of the light guide plate to the edge portion W2 of the light guide plate at a speed of about 400 mm / min. do.

As described above, when the laser beam L is linearly moved from the central portion W1 of the light guide plate to the edge portion W2 of the light guide plate while irradiating the laser beam L to the light guide plate W while the light guide plate W is rotating, As shown in FIG. 10, a spiral pattern CS which is almost circular in shape is processed in the light guide plate W, and the processed cross section as shown in FIG. 3 is displayed. Since the linear velocity is slow at the position close to the rotation center axis C (or the center W1 of the light guide plate), the depth of the cross section is deep, and the position is far from the rotation center axis C (or the center W1 of the light guide plate). As the linear velocity increases, the depth of the cross section becomes shallower.

At this time, when the reflection mirror 131 is rotated by a predetermined angle so that the angle θ1 between the optical axis L1 of the laser beam and the light guide plate W is formed at an acute angle rather than vertical, the laser beam L is applied to the light guide plate W. Compared with the cross section of the pattern in the case of vertical incidence, the cross section of the pattern is processed to have a lower inclination angle toward the edge portion W2 of the light guide plate as shown in FIG.

Flat panel displays generally require higher illuminance at the center than at the edges of the panel. It is perceived by the human eye to have a uniform illuminance over the entire panel area when the illuminance at the center of the panel is relatively high.

Referring to FIG. 12, when the laser beam L is incident perpendicularly to the light guide plate W and the pattern is formed, the light FL reflected by the pattern goes straight to the upper side of the light guide plate W. The roughness of W1 and the roughness of the edge portion W2 of the light guide plate do not have a large difference. On the other hand, referring to FIG. 13, when the laser beam L is incident to the light guide plate W at an acute angle to form a pattern having a lower inclination angle, the light FL reflected by the pattern is centered on the light guide plate W1. In this case, the illuminance of the central portion W1 of the light guide plate is relatively higher than that of the edge portion W2 of the light guide plate.

The laser beam L is linearly moved from the center portion W1 of the light guide plate to the edge portion W2 of the light guide plate while irradiating the laser beam L to the light guide plate W while the light guide plate W is rotating as in the present embodiment. Although the light guide plate W rotates, the laser beam L may be linearly moved from the edge portion W2 of the light guide plate to the center portion W1 of the light guide plate while irradiating the laser beam L to the light guide plate W. . Since the processing is the same principle as described above, further description will be omitted.

Meanwhile, in the embodiments of the laser pattern processing method of the present invention, a second embodiment in which the spiral pattern is processed in an elliptic shape as a whole will be described.

The light guide plate W is seated on the substrate support part 120 to align the light guide plate W so that the center part W1 of the light guide plate and the center part 121 of the substrate support part coincide with each other, and then the rotation axis penetrating the central part W1 of the light guide plate ( The light guide plate W is rotated with C) as the center of rotation. At this time, while the light guide plate W rotates, the rotational angular velocity of the light guide plate W is constantly maintained through the rotation driving unit 140.

Thereafter, while the light guide plate W is rotated 90 degrees, the laser beam L is linearly moved by the first distance in the direction R1 toward the edge portion W2 of the light guide plate. During rotation of the light guide plate W and linear movement of the laser beam L, the position on the major axis LA at the position on the minor axis SA of the ellipse among the spiral pattern ES trajectories as shown in FIG. 14. Curve ES1 is moved to.

Subsequently, while the light guide plate W is continuously rotated once more by 90 degrees, the laser beam L is directed in a direction R2 toward the central portion W1 of the light guide plate, that is, in a direction opposite to the direction when the first distance moves. Linearly moves by the second distance shorter than the distance. During rotation of the light guide plate W and linear movement in the opposite direction of the laser beam L, as shown in FIG. 15, the axis is shortened at a position on the long axis LA of the ellipse among the trajectories of the spiral pattern ES. The curve ES2 which is moved to the position on SA is processed.

Thereafter, the laser beam L is linearly moved by the first distance in the direction toward the edge portion W2 of the light guide plate while the light guide plate W is continuously rotated, and the laser is directed toward the central portion W1 of the light guide plate. The process of linearly moving the beam L by the second distance is repeated. In this case, the laser beam L is generally moved from the center portion W1 of the light guide plate to the edge portion W2 of the light guide plate, and the entire light guide plate W has an elliptical shape and a spiral pattern as shown in FIG. 11. (ES) is processed.

For example, while the light guide plate W rotates at a rotational angular speed of about 300 RPM, the laser head 130 is moved from the central portion W1 of the light guide plate to the edge portion W2 of the light guide plate at a speed of about 6000 mm / sec. The process of linearly moving by one distance is repeated and the process of linearly moving by the second distance from the edge portion W2 of the light guide plate to the central portion W1 of the light guide plate is repeated.

As in the present embodiment, the elliptical shape and the spiral pattern ES may be processed while linearly moving the laser beam L in the direction from the central portion W1 of the light guide plate toward the edge portion W2 of the light guide plate. Linearly moving the laser beam L in the direction toward the center W1 of the light guide plate by the first distance while the W rotates, and directing the laser beam L in the direction toward the edge W2 of the light guide plate. While repeating the linear movement by the second distance shorter than the first distance, it is also possible to process the overall pattern of the elliptical spiral shape ES. Since the processing is the same principle as described above, further description will be omitted.

The laser pattern processing apparatus and the laser pattern processing method according to the present embodiment configured as described above can reduce the pattern processing time of the light guide plate by processing the pattern with one curve without processing the pattern with a plurality of straight lines. The effect can be obtained.

In addition, the laser pattern processing apparatus and the laser pattern processing method according to the present embodiment configured as described above have a deep depth of the processing cross section at the center of the light guide plate and a shallow depth of the processing cross section at the edge of the light guide plate. The effect of satisfying the quality requirements of the light guide plate requiring high light efficiency can be obtained.

In addition, in the laser pattern processing apparatus and the laser pattern processing method according to the present embodiment configured as described above, by comparing the roughness of the edge portion of the light guide plate by processing the pattern at an acute angle, not vertical, between the optical axis of the laser beam and the light guide plate Thus, the effect of obtaining a relatively high illuminance of the central portion of the light guide plate can be obtained.

16 is an enlarged view of the laser head and the linear driving unit in the second embodiment of the laser pattern processing apparatus of the present invention. In FIG. 16, members referred to by the same reference numerals as the members shown in FIGS. 2 to 9 have the same configuration and function, and a detailed description thereof will be omitted.

In the first embodiment of the laser pattern processing method of the present invention, the pattern is processed under the condition that the rotational angular velocity of the light guide plate W is kept constant, but the spiral formed on the light guide plate W while the rotational angular velocity of the light guide plate W is changed. The pattern can be processed under the condition that the linear velocity at any position of the pattern of pattern is kept constant.

In this case, since the linear velocity at any position of the pattern is the same, the depth of the processed cross section of the pattern is also formed the same. In order for the illuminance at the central portion W1 of the light guide plate to be higher than the illuminance at the edge portion W2, the depth of the processing cross section of the pattern must be deepened toward the central portion W1 of the light guide plate. In FIG. 3, the linear driver 160 is inclined so that the distance between the laser head 130 and the light guide plate W is closer to the center portion W1 of the light guide plate from the edge portion W2 of the light guide plate. As shown in FIG. 16, the linear driving unit 160 is installed at a predetermined angle θ2 with respect to the horizontal plane H. As shown in FIG. Therefore, as the laser head 160 linearly moves to the center portion W1 of the light guide plate, the distance between the laser head 130 and the light guide plate W increases, so that the depth of the processed cross section of the pattern increases toward the center portion W1 of the light guide plate. Deepens.

10 and 11, when the pattern is processed on the light guide plate using the laser pattern processing apparatus of the present invention or the laser pattern processing method of the present invention, a light guide plate having a spiral pattern can be obtained.

The light guide plate W is formed with a spiral pattern CS and ES so as to diffuse and scatter light with uniform illuminance at each portion, and the central portion W1 of the light guide plate is the central portion P1 of the spiral pattern. To match.

As a pattern of the light guide plate, a circular pattern and a spiral pattern CS may be processed as shown in FIG. 10, or an elliptical pattern and a spiral pattern ES may be processed as shown in FIG. 11. It may be.

In this case, it is preferable that the ratio of the horizontal to the vertical of the spiral pattern ES having an elliptic shape as a whole is proportional to the ratio of the horizontal to the vertical of the light guide plate W. For example, when the ratio of the width and length of the light guide plate W is 4: 3, the ratio of the width and length of the elliptical spiral pattern ES is also 4: 3, so that the entire surface of the light guide plate W is filled. It is preferable that the pattern is processed.

The scope of the present invention is not limited to the above-described embodiments and modifications, but may be embodied in various forms of embodiments within the scope of the appended claims. Without departing from the gist of the invention claimed in the claims, it is intended that any person skilled in the art to which the present invention pertains falls within the scope of the claims described herein to various extents that can be modified.

1 is a view showing an example of a conventional laser pattern processing apparatus,

2 is a perspective view of a first embodiment of a laser pattern processing apparatus of the present invention;

3 is a cross-sectional view of the light guide plate processed by the laser pattern processing apparatus of FIG.

4 is a perspective view of a laser head of the laser pattern processing apparatus of FIG.

5 is a front view of the laser head of FIG. 4,

6 is a view illustrating a state in which the reflective mirror and the condenser lens of the laser head of FIG. 4 are rotated by an angle at the position shown in FIG.

7 is a cross-sectional view of the light guide plate processed by the reflective mirror and the condenser lens of FIG.

8 is an enlarged view of a portion “A” of the laser pattern processing apparatus of FIG. 2, and is a perspective view of the light guide plate alignment unit,

9 is a perspective view of a rotation driving unit of the laser pattern processing apparatus of FIG.

10 is a plan view of a first embodiment of a light guide plate of the present invention;

11 is a plan view of a second embodiment of a light guide plate of the present invention;

FIG. 12 is a diagram illustrating a path of light traveling through the light guide plate of FIG. 3.

FIG. 13 is a view illustrating a traveling path of light in the light guide plate of FIG. 7;

14 and 15 are views for explaining a second embodiment of the laser pattern processing method of the present invention,

Fig. 16 is an enlarged view of the laser head and the linear driver of the second embodiment of the laser pattern processing apparatus of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: laser pattern processing apparatus 110: laser oscillator

120: substrate support 130: laser head

131: reflection mirror 133: condensing lens

140: rotation driving unit 150: light guide plate alignment unit

Claims (15)

In the laser pattern processing apparatus for forming a pattern on a light guide plate using a laser beam, A laser oscillator for generating a laser beam; A substrate support for supporting a light guide plate to be processed; A laser head that irradiates a laser beam incident from the laser oscillator to the light guide plate, and linearly moves along a processing surface of the light guide plate; And a rotation driving unit for rotating the substrate support with a rotation axis passing through the center portion of the substrate support as the center of rotation. The method of claim 1, The laser head is a laser pattern processing apparatus, characterized in that it comprises a reflecting mirror rotatably installed so that the angle between the optical axis of the laser beam irradiated to the light guide plate and the light guide plate can be changed. The method of claim 2, The laser head further includes a condenser lens for condensing the laser beam reflected from the reflecting mirror to irradiate the light guide plate, And the condenser lens is synchronously rotated with the reflecting mirror so that the laser beam reflected from the reflecting mirror is incident vertically as the reflecting mirror is rotated. The method of claim 1, And a light guide plate alignment unit for aligning the light guide plate placed on the substrate support so that the center of the light guide plate coincides with the center of the substrate support to rotate the light guide plate and the substrate support at the same rotation axis. Laser pattern processing equipment. The method of claim 1, The rotary drive unit, And a motor, a drive roller fixed to the output shaft of the motor, a driven roller fixed to the rotating shaft of the substrate support, and a belt wound around the drive roller and the driven roller. The method of claim 1, The laser head is laser pattern processing apparatus characterized in that the linear movement inclined so that the distance between the laser head and the light guide plate closer to the center of the light guide plate from the edge portion of the light guide plate. In the laser pattern processing method for forming a pattern on a light guide plate using a laser beam, Rotating the light guide plate using a rotation axis passing through a central portion of the light guide plate as a rotation center; Irradiating a laser beam to the light guide plate while the light guide plate is rotating, linearly moving the laser beam from the center of the light guide plate to the edge of the light guide plate or from the edge of the light guide plate to the center of the light guide plate. Laser pattern processing method. The method of claim 7, wherein Linearly moving the laser beam, Linearly moving the laser beam by a first distance in a direction toward an edge of the light guide plate while the light guide plate is rotated by 90 degrees; Linearly moving the laser beam by a second distance shorter than a first distance in a direction toward the center of the light guide plate while the light guide plate is rotated once more by 90 degrees; And Repeating the linear movement by the first distance and the linear movement by the second distance while the light guide plate is continuously rotated, and linearly moving the laser beam from the center of the light guide plate to the edge of the light guide plate; Laser pattern processing method comprising the. The method of claim 7, wherein Linearly moving the laser beam, Linearly moving the laser beam by a first distance in a direction toward the center of the light guide plate while the light guide plate is rotated by 90 degrees; Linearly moving the laser beam by a second distance shorter than a first distance in a direction toward the edge portion of the light guide plate while the light guide plate is rotated once more by 90 degrees; And Repeating the linear movement by the first distance and the linear movement by the second distance while the light guide plate is continuously rotated, and linearly moving the laser beam from the edge of the light guide plate to the center of the light guide plate; Laser pattern processing method comprising a. The method according to any one of claims 7 to 9, And the rotational angular velocity of the light guide plate is kept constant while the light guide plate is rotating. The method according to any one of claims 7 to 9, And the linear velocity at any position of the pattern formed on the light guide plate is kept constant while the light guide plate is rotated. In the light guide plate used for the backlight unit, It is processed with a laser beam, and a spiral pattern is formed to diffuse and scatter light with uniform illuminance at each site. A light guide plate, the center portion of which coincides with the center portion of the spiral pattern. The method of claim 12, The spiral pattern is a light guide plate, characterized in that the whole in the form of a circle. The method of claim 12, The spiral pattern is a light guide plate, characterized in that the overall oval shape. The method of claim 14, The ratio of the width to the length of the spiral pattern is a light guide plate, characterized in that proportional to the ratio of the width and length of the light guide plate.

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