JP2009043708A - Pattern-formed backlight unit light guide plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming patterns on the surface of a light guide plate using a laser device while minimizing the reflection of light from an incoming light part to transmit the light to a light distribution part with minimum loss, and to provide the light guide plate. <P>SOLUTION: The backlight unit light guide plate has a light source installed on one side, and the patterns formed on one face with an X- and Y-axis plane having a Y-axis origin on the side where the light source is installed. The depths of the patterns are changed in accordance with Y-axis coordinates. The recessed individual patterns in elliptical shape are formed which are isolated from one another at predetermined spaces. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of forming a pattern having a curved shape on a surface of a light guide plate using a laser device, and a light guide plate for a backlight unit formed by the method. When forming a pattern on one side of the light guide plate, as the distance from the light source increases, the pattern is formed deeper, the reflection of light from the light incident part is minimized within the standard, and the light distribution part has the least loss. It is related with the light-guide plate which has the pattern formed by the formation method of the pattern which can be transmitted by.

  In the flat panel display field, the most widely commercialized and practically used liquid crystal display devices cannot emit light themselves, and therefore require a light emitting device called a backlight unit, and the liquid crystal display device The performance of this is highly dependent not only on its own characteristics but also on the performance of the backlight unit.

  Such a backlight unit includes a light guide plate, an optical film, a lamp assembly, and a mold frame. Such a liquid crystal display device has a direct light type and an edge type depending on the position of the lamp of the backlight unit. (Edge light).

  The direct type is a method in which the light generated from the light source is made uniform by using a diffusion plate and is incident on the liquid crystal panel. The edge type is a method in which the light generated from the side surface of the light guide plate is reflected on the light guide plate. In this method, the light is incident on the liquid crystal panel. As a technical trend in recent years, an edge type is more preferred because it keeps pace with the trend toward thinner and lighter liquid crystal display (LCD) modules.

  In such an edge-type backlight unit, a lamp assembly is installed on the side of the light guide plate to diverge light, and a lamp is formed so as to cover the lamp, and the light emitted from the lamp is reflected to the light guide plate. It consists of a reflective sheet.

  In order to form uniform brightness on the light guide plate, it is desirable that the backlight unit adopting the edge type diverges the emitted light uniformly, so that a pattern of a predetermined form is formed on one surface of the light guide plate. There must be.

  As a conventional method of forming a pattern on a light guide plate, there are a method of forming a mechanical V notch using diamond, a method of printing, and a method of forming a pattern using a laser.

  First, the mechanical cutting method using diamond reduces the productivity because of its relatively low speed, and does not emit light uniformly due to the roughness of the machined surface, and reproduces the intended pattern form as it is. There is a disadvantage that the reproducibility to be reduced.

  In addition, the printing method has a problem in forming a fine pattern because the corrosive liquid penetrates between the mask and the light guide plate when the corrosive liquid is used after exposure and phenomenon by the mask pattern. In the case of a thin plate, there arises a problem that the reproducibility is lowered and an environmental problem associated with the use of the corrosive liquid.

  Therefore, in recent years, a method of forming a light guide plate pattern using a laser device has been widely used.

  A method of forming a light guide plate pattern using a conventional laser device is to oscillate a laser by adjusting three factors of change, the X-axis interval on the plane of the light guide plate, the Y-axis interval, and the size of the individual pattern. Thus, a pattern is formed on the surface of the light guide plate, and the shape of the pattern thus formed is as shown in FIG.

  FIG. 1 is a diagram showing a pattern shape of a light guide plate formed by a conventional laser pattern forming method.

  As shown in the enlarged circle in the figure, the individual patterns of the light guide plate formed by the conventional laser pattern forming method are bar-shaped, and such bar-shaped individual patterns The shape is repeatedly formed with different X-axis spacing A, Y-axis spacing B, and size C.

  Compared with the printing method, the light guide plate on which the pattern is formed by the conventional laser pattern formation method has an effect of increasing the brightness by 8% to 10%, and the surface of the light guide plate is concave by the laser. This is a method that takes into account an environment where environmental problems due to the use of a corrosive liquid do not occur.

  However, in the conventional laser apparatus, when the light guide plate pattern applied to the backlight unit is formed, the laser output amount is always made equal during the pattern forming process, so that the depth of each individual pattern and While the shape is formed in the same and collectively, only the size of the individual patterns and the X and Y axis intervals between the individual patterns are adjusted. There is a problem of dark line generation.

  Further, irregular adjustment of the amount of change in the laser duty in the X-axis and Y-axis directions may cause stripes and unevenness on the screen.

  In addition, since there are only three factors for adjusting the laser duty: the X-axis interval, the Y-axis interval, and the bar size, convenience and efficiency in adjusting the distribution of luminance and pattern appearance. There is a problem that goes down.

  The present invention is for solving the above-mentioned problems, and its purpose is to apply a different output amount for each pattern line during laser processing of a light guide plate for a backlight unit, and to change the shape of the pattern depth. By forming the pattern, it is to prevent formation of a dark line of a pattern that has occurred during laser processing of a conventional pattern.

  Another object of the present invention is to form a dot-shaped individual pattern and control the laser duty value including the laser output amount for each dot to improve the luminance.

  Another object of the present invention is to control the change in the shape and size of the dot-shaped individual patterns, thereby reducing the amount of change in the Y-axis displacement and regulating the laser output in the X-axis direction and the Y-axis direction. Therefore, it is intended to prevent the occurrence of dark lines and the appearance defect.

  Furthermore, another object of the present invention is to add a laser output amount, a dot shape and a dot depth associated therewith in addition to the laser duty adjustment factor according to the conventional method, thereby enabling more precise and efficient luminance. It is also possible to adjust the distribution of the pattern appearance.

  A light guide plate for a backlight unit in which a pattern according to the present invention for solving the above problems is formed, a light source is installed on one side, and the side on which the light source is installed is used as the origin of the Y axis. A pattern is formed on one surface, and the depth of the pattern is changed in accordance with the Y-axis coordinates. Ellipse-shaped concave individual patterns are formed at predetermined intervals.

  In addition, the backlight unit light guide plate on which the pattern is formed may have at least one of the width or the width of the concave individual pattern increasing as the Y-axis coordinate increases. It is preferable for improvement and prevention of poor appearance.

  In addition, it is preferable for forming the pattern that the light guide plate for the backlight unit on which the pattern is formed is formed with a laser device.

  Further, the pattern formed so that the depth of the pattern changes according to the Y-axis coordinates may be formed by the B-spline interpolation method, so that the depth of the pattern having a gentle curve shape is formed. It is preferable in forming a saddle shape.

  According to the present invention, during laser processing of the light guide plate for the backlight unit, a laser duty value including another output amount is applied to each pattern line to form a pattern depth, thereby forming a conventional pattern laser. It is possible to prevent the formation of dark lines in the pattern that has occurred during processing.

  In addition, according to the present invention, it is possible to form a dot-shaped individual pattern and control the laser duty value including the laser output amount for each dot to improve the luminance.

  Further, according to the present invention, by controlling the change in the shape and size of the dot-shaped individual pattern, the amount of change in the Y-axis displacement is reduced, and the laser output in the X-axis direction and the Y-axis direction is regularly changed. Thereby preventing the generation of dark lines and the appearance defect.

  Further, according to the present invention, in addition to the laser duty adjustment factor according to the conventional method, by adding the laser output amount, the dot shape and the dot depth associated therewith, more precise and efficient brightness and pattern appearance. The distribution can be adjusted.

  Hereinafter, a light guide plate for a backlight unit having a pattern according to the present invention will be described in detail with reference to the drawings.

  FIG. 2A is a cross-sectional view of a light guide plate for a backlight unit on which a pattern according to the present invention is formed, and FIG. 2B is a graph showing the shape of the pattern depth associated therewith.

  As shown in FIG. 2A, the light guide plate manufactured by the method for forming the light guide plate pattern for the backlight unit on which the pattern according to the present invention is formed is formed as the distance from the light source increases, that is, as the Y coordinate increases. By having a shape in which the depth of the pattern increases, the light emitted from the light source is reflected so as to have the same luminance. The shape of the individual pattern is a concave elliptical shape.

  As shown in FIG. 2B, the light guide plate of FIG. 2A has a pattern having a depth T (profile) indicated by a cross section of the light guide plate pattern when light sources are installed at both ends of the Y axis of the light guide plate. In FIG. 4B, indicated as “A”), the parabola shape must be drawn generally as the Y coordinate increases.

  Here, since the same laser duty and focus are applied to the pattern formed on one line of the X axis having the same Y coordinate, the width, width, and individual of the individual pattern formed on the same line, etc. The X-axis spacing between patterns is the same.

  Since the pattern formed on the light guide plate must have a different pattern depth for each X-axis line, a conventional laser device that applies a laser output amount uniformly for each line is used. In the processing method, production is difficult.

  That is, by controlling the short-circuiting of the pulse signal, the depth of the pattern formed for each line must be changed together with the change of the laser duty that changes the size of the individual pattern on the two-dimensional plane. Therefore, it is necessary to change the output amount of the laser. For this reason, a control system for processing an enormous amount of data in the laser apparatus is required.

  In addition, when the parabola shape is not correctly formed, light from the light source is not transmitted to the central portion of the screen and is lost, and a phenomenon occurs in which the luminance of the central portion decreases compared to the peripheral portion. In order to prevent the loss of luminance, the laser duty value including the laser output amount and the focus must be adjusted appropriately for each pattern line.

  In the manufacture of a light guide plate for a backlight unit in which a pattern according to the present invention is formed, a laser device capable of adjusting a laser duty value including a laser output amount can be used. Preferably, a rapid and efficient pattern is used. For this processing, a laser apparatus equipped with the following control system is utilized.

  FIG. 3 is a view showing a laser device used in a pattern forming process of a light guide plate for a backlight unit according to the present invention for solving the above-mentioned problems.

  As shown in the figure, a light guide plate pattern forming laser device 100 for a backlight unit according to the present invention includes a control system 10 for controlling a motion unit 20 and an output unit 30, and preferably a servo motor and a servo drive. And a motion unit 20 that controls movement of the output unit according to an operation signal, and an output unit 30 that is moved by the motion unit 20 and outputs a laser according to the output signal to form a pattern on the light guide plate. Configured.

  In addition, the control system 10 according to the present invention includes a program unit 1 that executes a program for the operation of the output unit and the output of the laser, and each X axis that is connected to the program unit 1 and corresponds to a specific Y coordinate of the light guide plate. A local bus 2 that receives and processes pattern data of one line, a motion control unit 3 that controls the motion unit 20 using data received from the local bus 2, and an output unit that uses data received from the local bus 2 And an output control unit 4 for controlling 30.

  The program unit 1 executes various control data and programs, arranges CAD pattern data designed by the user in accordance with the order of work, and converts the CAD pattern data into a pulse signal that is a laser output signal. It is configured as a CPU of a computer.

  The motion control unit 3 and the output control unit 4 are preferably mounted together with the input / output terminal 5 on the same local bus 2 including a PCI bus (Peripheral Component Interconnect Bus) and configured to control in real time. The local bus 2 is utilized as a PCI bus because even if the PCI bus is commercialized as the local bus 2 and the CPU type is different, it can be connected to any CPU as long as it has a corresponding bridge circuit. This is because the possible properties, that is, compatibility is ensured.

  As described above, when the control system 10 is configured by mounting the motion control unit 3 and the output control unit 4 on one local bus 2, the output change which has been a problem of the prior art described above. In the control, there is an effect of preventing a delay in processing time.

  In other words, the technical feature of the control system 10 is that the output change control unit 5 ′ is separately provided as in the prior art, and after the pattern forming operation for one line of the X axis in the previous order is completed, In order to work on one line of the X axis, in order to prevent a delay in processing time when executing the process of changing the output of the laser duty value including the laser output amount for the next X axis line and adjusting the focus. The output change control unit 5 ′ is excluded from the configuration, and both the motion control unit 3 and the output control unit 4 are mounted on one local bus 2, and changes in output signals are collectively performed in the local bus 2. This is the realization of a control system that can be processed.

  A method of manufacturing using the laser device 100 having the above configuration will be described.

  The method for forming a light guide plate pattern for a backlight unit according to the present invention includes a data calculation step S10 and a pattern formation step S20.

  In the data calculation step S10, the pattern data designed and stored by the user is recognized and read out by the program unit 1, aligned in accordance with the work order, and the pattern data is converted into a pulse signal which is a laser output signal. This is a preliminary step before the step S20 for full-scale pattern formation.

  In the pattern forming step S20, the processing data for each X-axis line corresponding to the specific coordinate of the Y-axis in the light guide plate among the pulse signals is sequentially transmitted to the local bus 2 by the first-in first-out method. The motion control unit 3 and the output control unit 4 transmit the operation signal and the output signal, respectively, to move the output unit 30, and the output unit 30 adjusts the laser duty value and the focus to lower the lower end from the upper end of the light guide plate. It is performed by forming a pattern in order up to the part.

  In the pattern forming step S20, when adjusting the duty value of the laser to be oscillated, the depth and size of the pattern formed by changing the laser output amount according to the Y-axis coordinates increases the Y-axis coordinates. It is done to change according to.

  Of course, individual patterns formed in the same manner as in the conventional method are performed by adjusting the lengths of the X axis and the Y axis and the distance between the X axis and the Y axis.

  The depth shape of the pattern formed in this way has a curved shape, and the more smoothly the curved shape is controlled, the more precise the pattern can be formed. The light scattered from the pattern of the light plate can represent uniform brightness. Therefore, a curve interpolation method for controlling the curve of the pattern formed by the program unit 1 must be prepared in advance so that the depth shape of the pattern forms a gentle curve.

  The curve interpolation method is possible by controlling the laser duty value so as to change for each line.

  First, the case where the progressive curve interpolation method is applied among the curve interpolation methods will be described. In the gradual change method, L1 is the first Y coordinate value that the output unit 30 changes, L2 is the second Y coordinate value that the output unit 30 changes, La is the laser output amount that changes at the L1 position, and Lb is L2 When the laser output amount that changes depending on the position and R1 is the rate of change of the laser output amount when moving from L1 to L2 position, the rate of change of the laser output amount is expressed by the formula R1 = (La−Lb) / (L2−L1). The laser applied to one X-axis line corresponding to a specific value on the Y-axis, where A1 is the current Y-axis coordinate of the output unit and S is the laser output amount to be applied. The output amount is derived by the equation S = R1 * A1.

  FIG. 4A and FIG. 5A are graphs showing the results of changing the laser duty value and the focus, respectively, by the progressive curve interpolation method as the Y-axis coordinate increases.

  As shown in FIGS. 4A and 5A, when the gradual curve interpolation method is applied, the shape of the curve is not smoothly connected. Therefore, when the pattern is formed, there is a possibility that a boundary line or a stripe is formed on the pattern. is there. Therefore, in order to prevent this, the shape of the curve must be controlled so as to be connected more gently.

  Therefore, in the present invention, a B-spline interpolation method is used as the curve interpolation method.

The B- spline curve interpolation method, a number of control points P _o on the _curve, P 1, _{P 2} · · _·, coordinate values for P _n, i.e. if specifying the laser duty value for each line of the pattern, at runtime pattern forming operation of each line in the output control section 4, by commanding the laser duty value, resulting in _{P o, P 1, P 2} ···, the curve connecting the P _n are gently formed Applied to correct so that

で表わされ、ｕは、所定の範囲ｕ_ｍｉｎ≦ｕ≦ｕ_ｍａｘで定義されるパラメータであり、Ｎ_ｋ，ｄ（ｕ）は、スプライン基底関数であり、下記のような漸化式形態の数式で表わされる。

A mathematical expression applied to the B-spline interpolation method is a formula applied to a general B-spline curve, and approximates each k-th position vector P _k at (n + 1) control points. When the spline curve is a constant selected arbitrarily in the range of 2 ≦ d ≦ n + 1 in the (d−1) degree polynomial,

U is a parameter defined by a predetermined range u _min ≦ u ≦ u _max , N _{k, d} (u) is a spline basis function, and has the following recurrence form It is expressed by a mathematical formula.

Here, u _k is a node (knot), u ₀ , u ₂ ..., U _m are nodes in m + n + d and n + d + 1 sections. knot vector).

The spline basis function N _{k, d} (u) is defined by d sections between control points in the k-th to k + d-th sections, and is a function capable of local control of a curve that affects only the d sections. It is.

  If the knot vector sequence is formed in a non-uniform form, a mathematical expression defined by the following NURBS (Non-Uniform Rational B-Spline) is used. Interpolation methods can be used.

で表される数式である。ここで、ω_ｋはｋ番目の制御点の加重値として定義され、当該加重値とスプライン基底関数とによって曲線の形態が変化する。 That is, when n + 1 control points are given,

It is a numerical formula represented by. Here, ω _k is defined as a weight value of the k-th control point, and the form of the curve changes depending on the weight value and the spline basis function.

  The results of controlling the laser duty value and the focus using the B-spline curve interpolation method to which the above formula is applied are as shown in FIGS. 4B and 5B, respectively.

  As shown by dotted lines in FIGS. 4B and 5B, if the B-spline curve interpolation method is utilized, no step is formed on the curve connecting the control points, and a gentle pattern shape is formed. Thus, precise control can be performed so as not to form a boundary line on the pattern.

  A light guide plate for a backlight unit according to the present invention in which a pattern is formed by the pattern forming method will be described through preferred embodiments and comparative examples of the present invention.

  First, in order to explain the shape and arrangement of patterns formed by the pattern forming method and the size of individual patterns, as shown in FIG. 6, a backlight unit (model name LTN154BT02) in which a light source is installed on one side. X-axis and Y-axis lengths, arrangement forms, and individual pattern shapes of the portion of the light incident portion 10 mm closest to the light source of the light guide plate, the central portion, and the portion of the anti-light incident portion 10 mm farthest from the light source Was measured.

The measurement results are as shown in Table 1.

  As shown in Table 1, the shape of the formed individual pattern is an elliptical shape having a long axis in the X-axis direction, and the arrangement is such that the pitch (pitches) of the X-axis and Y-axis of the light incident portion is 747 μm, It is 554 μm at the center and 414 μm at the anti-incident part, and it can be seen that the distance between the incident part and the anti-incident part increases.

  In addition, the size of the formed individual pattern is as follows. The length of the X axis is 170 μm at the light incident part, 236 μm at the light incident part, and the length of the Y axis is 72 μm at the light incident part. It can be seen that the depth of the pattern is 112 μm at the light portion, and is 12 μm at the light incident portion and 47 μm at the anti-light incident portion, which increases.

  Next, this will be described with reference to FIG. 7 which is a graph showing a change curve of the pattern density. FIG. 7A is a comparative example, and is a graph showing the pattern density of the X-axis line according to the change of the Y-axis coordinate of the pattern formed by the conventional pattern forming method, and FIG. 7B is an embodiment of the present invention. It is a graph which shows the pattern density of the X-axis line accompanying the change of the Y-axis coordinate of the pattern formed by the pattern formation method concerning.

  7A and 7B, the horizontal axis of the graph indicates coordinates in the Y-axis direction of the light guide plate pattern, and the vertical axis of the graph indicates the density for each line.

  As shown in FIG. 7A, when the pattern is formed by the conventional pattern forming method, in order to adjust the luminance, the two-dimensional size of the individual pattern, the X-axis interval between the individual patterns, and the Y-axis interval 3 Since only one factor can be adjusted, it is necessary to show an irregular pattern density due to the occurrence of a constant brightness, and in a line where the amount of change in the pattern density is abrupt, unevenness may occur or dark lines may be formed .

  However, as shown in FIG. 7B, the pattern density of the light guide plate formed by applying the pattern forming method according to the present invention has a constant gradient and increases as the Y-axis coordinate increases. I can confirm that. That is, a desired luminance distribution can be obtained by moderately changing the pattern density.

  The reason why the phenomenon appears is that, when the pattern forming method according to the present invention is applied, the laser duty value including the laser output amount can be adjusted for each line, thereby making it possible to adjust the two-dimensional pattern of the individual pattern for brightness adjustment. This is because the depth of the individual pattern and the shape of the individual pattern can be adjusted in addition to the above three factors of the size, the X-axis interval between the individual patterns, and the Y-axis interval.

  FIG. 8 is a CAD diagram showing the overall shape of the backlight unit light guide plate according to the embodiment of the present invention and the comparative example. FIG. 8A is a comparative example, and is a CAD diagram of a pattern formed by a conventional pattern forming method. FIG. 8B is a CAD of a pattern formed by a pattern forming method according to an embodiment of the present invention. FIG.

  As shown in FIGS. 8A and 8B, compared with the case where the pattern is formed by the conventional method, the pattern of the light guide plate formed according to the present invention has a sharp luminance depending on the amount of change in the X-axis and Y-axis intervals. It can be seen that there is no change, and in particular, a stripe is formed at the lower end of FIG. 8A, but in the present invention, the phenomenon shown in FIG. 8B does not appear.

  Finally, evaluation of light measurement of the light guide plate for a backlight unit on which the pattern according to the present invention is formed will be described.

  The measurement temperature is 23 ° C, the measurement humidity is 55% in a dark room, no wind atmosphere, and the measuring instrument is TOPCON BM-7 fast, the measurement distance is 500 mm, the field is 2 °, and the light guide plate is heat treated for 30 minutes And then measured. The measurement points were extracted by a 9-point measurement method for extracting 9 points on the pattern and a 25-point measurement method for extracting 25 points. The measurement points of the light incident part by the 25-point measurement method are as shown in FIG.

  FIG. 10 is a diagram showing the results of light measurement by the 25-point measurement method in the embodiment and comparative example of the present invention, and FIG. 11 shows the light measurement results by the 9-point measurement method in the embodiment and comparative example of the present invention. FIG.

The average value of the 25-point measurement method shown in FIG.

  As shown in FIG. 10, FIG. 11 and Table 2, the light guide plate having the pattern formed according to the present invention has an improved brightness of about 114% compared to the light guide plate having the pattern formed by the conventional method. You can see that

  The foregoing has been described in detail with reference to the preferred embodiments of the present invention. However, the scope of rights of the present invention is not limited to the above-described embodiments, and can be realized as various embodiments within the scope of the appended claims. Any person having ordinary knowledge in the technical field to which the present invention pertains without departing from the scope of the present invention claimed in the scope of the claims can be modified to various extents that can be modified. Is considered to be within the scope of

It is the shape of the pattern of the light-guide plate formed with the formation method of the conventional laser pattern. It is sectional drawing of the light-guide plate for backlight units in which the pattern which concerns on this invention was formed. It is a graph which shows the shape of the depth of the pattern of the light-guide plate for backlight units in which the pattern which concerns on this invention was formed. It is a figure which shows the laser apparatus used in the pattern formation process of the light-guide plate for backlight units which concerns on this invention. It is a graph which shows the result of having changed the laser duty value by the gradual curve interpolation method according to the increase in the Y-axis coordinate. It is a graph which shows the result of having changed the laser duty value by the B-spline curve interpolation method according to the increase in a Y-axis coordinate. The graph which shows the result of having changed the laser focus value by the gradual curve interpolation method according to the increase in Y-axis coordinates. It is a graph which shows the result of having changed the laser focus value by the B-spline curve interpolation method according to the increase in Y-axis coordinates. It is a figure which shows the measurement part of the light-guide plate for backlight units by embodiment of this invention. It is a graph which shows the pattern density of the X-axis line accompanying the change of the Y-axis coordinate of the pattern formed by the conventional pattern formation method. It is a graph which shows the pattern density of the X-axis line accompanying the change of the Y-axis coordinate of the pattern formed by the formation method of the pattern which concerns on one Embodiment of this invention. It is a CAD figure of the pattern formed by the conventional pattern formation method. It is a CAD figure of the pattern formed by the formation method of the pattern concerning one embodiment of the present invention. It is a figure which shows the measurement point of the light-incidence part by embodiment and comparative example of this invention. It is a figure which shows the result of the optical measurement by the 25-point measuring system by embodiment and comparative example of this invention. It is a figure which shows the result of the optical measurement by the 9-point measuring system by embodiment and comparative example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Program part 2 Local bus 3 Motion control part 4 Output control part 5 Input / output terminal 10 Control system 20 Motion part 30 Output part 100 Laser apparatus

Claims (5)

In the light guide plate for the backlight unit, the light source is installed on one side, and the side on which the light source is installed is the X-axis and Y-axis planes with the Y-axis origin, and the pattern is formed on one side.
According to the Y-axis coordinates, the depth of the pattern is changed, and the oval concave individual patterns are formed separated by a predetermined interval. Light board.   The light source is installed on both sides, and the pattern depth changes as the distance from the light sources on both sides increases, and the pattern connecting the pattern depths in the Y-axis direction forms a parabola that swells most in the center. The light guide plate for a backlight unit having the pattern according to claim 1 formed thereon.   The light guide plate for a backlight unit on which the pattern is formed has at least one of a width or a width of the concave individual pattern increasing as the Y-axis coordinate increases. A light guide plate for a backlight unit, on which the pattern according to 1 is formed.   The light guide plate for a backlight unit on which the pattern is formed is formed by a laser device, and the light guide plate for the backlight unit on which the pattern according to any one of claims 1 to 3 is formed. Light board.   5. The pattern according to claim 4, wherein the pattern formed so that the depth of the pattern changes according to the Y-axis coordinates is formed by a B-spline interpolation method. The formed light guide plate for the backlight unit.

Images