WO2012074288A2

WO2012074288A2 - Method for processing optical pattern of light guide plate

Info

Publication number: WO2012074288A2
Application number: PCT/KR2011/009210
Authority: WO
Inventors: 이호연; 한재현
Original assignee: 레이져라이팅(주)
Priority date: 2010-12-01
Filing date: 2011-11-30
Publication date: 2012-06-07
Also published as: WO2012074288A3; KR101021570B1

Abstract

The present invention relates to a method for processing an optical pattern, in which an optical pattern is formed by a laser beam and an optical characteristic is improved, wherein in a laser processing device comprising: a surface plate which is transferred in a straight-line reciprocal manner; and a laser head which is transferred in a straight-line reciprocal manner in a direction crossing the transferring direction of said surface plate and irradiates laser toward said surface plate, the method comprises the steps of: a first load step for supporting a light guide plate on said surface plate; a first optical pattern formation step for allowing said laser head to be transferred in a straight-line reciprocal manner by transferring said surface plate, and forming a first optical pattern on said light guide plate; a light guide plate rotating step for rotating said light guide plate at a predetermined angle; a second load step for supporting the light guide plate on said surface plate; and a second optical pattern formation step for allowing said laser head to be transferred in a straight-line reciprocal manner by transferring said surface plate, and forming a second optical pattern on said light guide plate.

Description

Optical pattern processing method of light guide plate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing an optical pattern of a light guide plate, and more particularly, to an optical pattern processing method capable of improving optical characteristics such as brightness, brightness, and luminance uniformity while forming an optical pattern by a laser beam.

Liquid crystal displays (LCDs) do not have self-luminous, and thus require a separate light emitting source. Such a light emitting source is disposed on the rear side of the liquid crystal panel and irradiates light through the liquid crystal panel, so it is commonly referred to as a back light unit (BLU).

Ideally, the backlight unit functions as a surface light source, but it is technically difficult to realize a surface light source with uniform luminance across the entire surface, so that a backlight source such as a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED) or A method of diffusing light irradiated from a light source similar to the point light source to adjust the state close to the surface light source is used. Here, the light guide plate (LGP) plays an important role for light diffusion.

The light guide plate is a plate material usually made of synthetic resin, and a predetermined optical pattern is formed so that light emitted from a light source disposed on the side or bottom is uniformly diffused toward the front surface. The optical pattern achieves a desired purpose by reflecting or refracting light. The uniformity of luminance on the entire surface of the light guide plate is determined by the shape of the optical pattern. Therefore, the optical pattern of the light guide plate is required to be increasingly complex and precise, and it is also an urgent problem to shorten the time required to form the optical pattern according to the large area of the display device.

In order to solve such a problem, techniques for forming an optical pattern on a synthetic resin sheet using a laser beam have been developed.

1 is a schematic perspective view showing an example of a light guide plate processing apparatus for forming a pattern on a light guide plate with a laser according to the prior art. The laser head 20 which oscillates itself or receives the laser beam from the outside and finally irradiates the laser beam 20 is installed to reciprocate in a linear direction with respect to the frame 10. The light guide plate 40 supported by the moving surface plate 30 is positioned below the laser head 20, and is transferred by the surface plate 30. In this case, the feeding direction of the surface plate 30 is transferred to the laser head 20. It is the direction across the direction. For example, if the laser head 20 is conveyed in the left-right direction, that is, the arrow A direction of FIG. 1, the surface plate 30 is conveyed in the front-rear direction, that is, the arrow B direction of FIG. More specifically, in the state in which the surface plate 30 is paused, the laser head 20 is moved once from left to right in the A direction while irradiating a laser and irradiating a laser according to a predetermined rule. After the optical pattern is formed on the surface plate 30 is transferred to the frame 10 side by a predetermined distance and then stopped again, the laser head 20 is transferred once from the right side to the left side along the A direction, and also the optical pattern. To form the equation. This method is a very efficient layout for miniaturizing the light guide plate processing device and shortening the processing time, and also has high operational reliability and is widely used.

However, when the optical pattern is formed in this manner, as illustrated in FIG. 2, the optical patterns 50 formed on the light guide plate 40 appear in a form in which dashes arranged in a row are repeated in a double row. That is, in FIG. 2, a plurality of dashes are arranged side by side in the left and right directions. Of course, the optical pattern 50 may be in the form of dots or lines in addition to the dash. The light source 60 is installed on the light guide plate 40, but the light source 60 is disposed on the upper side and the lower side based on the drawing direction of FIG. 2 to irradiate light in the vertical direction. Meanwhile, as illustrated in FIG. 3, the light guide plate 40 may be disposed while being left and right of the light guide plate 40 while leaving the light guide plate 40 intact. As a result, in the case of FIG. 3, the optical characteristics of the light guide plate 40 are significantly reduced in comparison with the case of FIG. 2. This is because there is a difference in the arrangement of the optical pattern 50 that can scatter and reflect the light on the optical path through which the light from the light source 60 travels. In other words, when the optical pattern is formed by the laser beam, it is difficult to form a complicated optical pattern, and thus there is a problem that the optical characteristics of the light guide plate 40 are not improved to a predetermined level or more.

The present invention has been made to solve the above problems, the optical characteristics of the light guide plate by making the optical pattern more complicated while forming the optical pattern in the light guide plate one by one while the transfer direction of the laser head and the transfer direction of the light guide plate intersect. An object of the present invention is to provide an optical pattern processing method of a light guide plate capable of improving the light guide plate.

Other objects, specific advantages and novel features of the invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the accompanying drawings.

In order to achieve the above object, the optical pattern forming method of the light guide plate according to the present invention, for straight irradiating the laser toward the surface while a straight reciprocating transfer in a direction intersecting the transfer direction of the surface and the surface plate A laser processing apparatus including a laser head, comprising: a first rod step of supporting a light guide plate on the surface plate, and a first optical pattern formed on the light guide plate by linearly transferring the laser head while transferring the surface plate; An optical pattern forming step, a light guide plate rotating step of rotating the light guide plate at a predetermined angle, a second rod step of supporting the light guide plate on the surface plate, and a linear reciprocating transfer of the laser head while transferring the surface plate to provide the light guide plate. And a second optical pattern forming step of forming a secondary optical pattern.

The optical pattern forming method of the light guide plate according to the present invention may further include a returning step of returning the surface plate to the original position prior to the light guide plate rotation step, wherein the first optical pattern forming step and the second optical pattern forming step The conveying directions of the surface plates are the same.

In addition, the optical pattern forming method of the light guide plate according to the present invention, in the first optical pattern forming step, the conveying distance of the surface plate is greater than the length of the light guide plate in the conveying direction of the surface plate, the first optical pattern forming step and the second optical In the pattern forming step, the feeding direction of the surface plate may be opposite to each other.

According to the present invention, the optical pattern is sequentially formed in a row while the conveying direction of the laser head and the conveying direction of the light guide plate are sequentially formed, but after the rotation of the light guide plate, an additional optical pattern is additionally formed, thereby forming an optical pattern having a more complicated shape. As a result, the optical properties of the light guide plate can be significantly improved.

1 is a perspective view showing an example of a light guide plate processing apparatus according to the prior art,

FIG. 2 is a plan view illustrating a state of use of the light guide plate manufactured by the light guide plate processing apparatus of FIG. 1; FIG.

3 is a plan view showing another use state of the light guide plate manufactured by the light guide plate processing apparatus of FIG.

4 to 6 are explanatory views showing each step of the embodiment of the optical pattern processing method of the light guide plate according to the present invention;

7 is a plan view showing an example of a light guide plate manufactured by the optical pattern processing method of the light guide plate according to the present invention;

8 is a plan view showing another example of the light guide plate manufactured by the optical pattern processing method of the light guide plate according to the present invention;

9 is an explanatory diagram showing a light guide plate rotating step of another embodiment of an optical pattern processing method of a light guide plate according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the light guide plate optical pattern forming method according to the present invention.

4 to 6 are explanatory views showing each step of the embodiment of the optical pattern processing method of the light guide plate according to the present invention, Figure 7 is an example of a light guide plate manufactured by the optical pattern processing method of the light guide plate according to the present invention. It is a top view shown.

The present invention is applied to a laser processing apparatus for forming an optical pattern on a light guide plate, wherein the laser processing apparatus refers to the operation in the form as illustrated in FIG. Specifically, including the surface plate 30 and the laser head 20, the surface plate 30 is for supporting the light guide plate 40 to be processed, is installed so as to be reciprocated in a linear direction. The laser head 20 is used to form an optical pattern on the light guide plate 40 by finally irradiating a laser beam. The laser head 20 is installed to be reciprocated in a straight direction along the frame 10. It should intersect the conveying direction of 30). The laser beam irradiated from the laser head 20 may be generated from a laser oscillator embedded in the laser head 20, or may be generated externally and delivered to the laser head 20.

First, as illustrated in FIG. 4, the light guide plate 40 is loaded and supported on the surface plate 30 (hereinafter, referred to as “first load step”). Here, the 'load' means that the light guide plate 40 is placed on the surface plate 30 so as to be simply supported, and the plate surface of the light guide plate 40 is plated by a flat chuck such as a vacuum chuck or an electrostatic chuck. It is also included that the light guide plate 40 is fixed to the surface plate 30 by pressing or supporting the side surface (thickness surface) of the light guide plate 40 by being in close contact with 30 or by a configuration such as a movable jaw.

Next, as indicated by the arrows in FIG. 4, the surface plate 30 is transferred in one direction by a predetermined distance and then stopped, and the laser head 20 is moved in one direction, for example, in the state in which the surface plate 30 is stopped. The optical patterns are arranged on the light guide plate 40 by moving from left to right with respect to the direction. The optical pattern formed at this time may be a straight line in one line, an intermittent straight line, that is, a dash, or one of intermittent dots, or a combination thereof. Then, the surface plate 30 is transferred to a predetermined distance and stopped again. In this state, the laser head 20 is transferred from the opposite direction, for example, from the right side to the left side, to form another line of optical patterns on the light guide plate. While repeating such an operation, an optical pattern is first formed on the light guide plate 40 (hereinafter, referred to as 'first optical pattern forming step'). The optical pattern thus formed has a form in which dashes arranged in a row are arranged in a double row as illustrated in FIGS. 2 and 3.

When the optical pattern is first formed, the light guide plate 40 is rotated at a predetermined angle (hereinafter referred to as the 'light guide plate rotating step'). At this time, the rotation angle is to determine the shape of the optical pattern in the processed light guide plate, can be arbitrarily determined between 0 degrees to 90 degrees. For example, when the rotation angle is 90 degrees, the finished light guide plate may have a cross optical pattern 50 as illustrated in FIG. 7. The viewpoint of the process of rotating the light guide plate 40 may be after all of the primary optical patterns are formed over the entire surface of the light guide plate 40, or may be a time point where the optical pattern 50 is formed only at a portion thereof. In the former case, if the optical pattern 50 as shown in FIG. 7 can be obtained, in the latter case, as shown in FIG. 8, the optical pattern 50 in which the dashes are arranged is partially different. In the case of the former case, it is preferable to further include the step of returning the surface plate 30 to its original position (hereinafter, 'return step') before the light guide plate rotation step. That is, as illustrated in FIG. 5, the surface plate 30 is transferred to pass the frame 10 to form all the optical patterns over the entire surface of the light guide plate 40, and then the surface plate 30 is transferred in the direction of the arrow. As illustrated in FIG. 4, the surface plate 30 is completely returned to the same position as in the first loading step of loading the light guide plate 40 onto the surface plate 30.

When the surface plate 30 returns to its original position in the returning step, as shown in FIG. 6, the light guide plate 40 is unloaded from the surface plate 30, rotated by a predetermined angle, and then loaded again onto the surface plate 30. (The "Second Loading Phase").

Then, an optical pattern is formed on the light guide plate 40 once again in the same manner as the first optical pattern forming step (hereinafter, 'second optical pattern forming step'). As a result, the conveyance direction of the surface plate in the second optical pattern forming step becomes the same as the conveying direction of the surface plate in the first optical pattern forming step.

Meanwhile, as another embodiment, the light guide plate rotating step may be performed when the optical pattern is first formed on the entire surface of the light guide plate 40 as shown in FIG. 5. This is illustrated in FIG. 9. In this case, in the first optical pattern forming step, the conveyance distance of the surface plate 30 is the length of the light guide plate 40, that is, the length of the light guide plate along the conveying direction of the surface plate. The length of the light guide plate 40 should be equal to or greater than the length of the light guide plate 40, and the feeding directions of the surface plate in each of the first optical pattern forming step and the second optical pattern forming step should be opposite to each other. In this case, there is an advantage that no return step is required. However, one side of the frame 10 should be able to load and unload the light guide plate, and the opposite side should be able to rotate the light guide plate 40, which is necessary as compared with the previous embodiment illustrated in FIGS. 4 to 6. The space can be widened.

* One embodiment of the present invention described above and shown in the drawings should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

Claims

In the laser processing apparatus comprising a table for straight reciprocating transfer and a laser head for irradiating a laser toward the table while linearly reciprocating in a direction crossing the transfer direction of the table.

A first rod step of supporting the light guide plate on the surface plate;

Forming a first optical pattern on the light guide plate by linearly reciprocating the laser head while transferring the surface plate;

A light guide plate rotating step of rotating the light guide plate at a predetermined angle;

A second rod step of supporting the light guide plate on the surface plate;

And forming a second optical pattern on the light guide plate by linearly reciprocating the laser head while transferring the surface plate.
The method of claim 1,

And a returning step of returning the surface plate to the original position before the step of rotating the light guide plate,

The optical pattern forming method of the light guide plate of the first optical pattern forming step and the second optical pattern forming step, characterized in that the conveying direction of the surface plate is the same.
The method of claim 1,

In the first optical pattern forming step, the conveyance distance of the surface plate is equal to or greater than the length of the light guide plate in the conveying direction of the surface plate,

The optical pattern forming method of the light guide plate, characterized in that the conveying direction of the surface plate in the first optical pattern forming step and the second optical pattern forming step are opposite to each other.