KR20030090371A - Scribing apparatus for light guide panel and calibrating method thereof - Google Patents

Abstract

PURPOSE: A scribing device for a light guide panel using laser and a correcting method thereof are provided to improve the luminance and the uniformity of the light guide panel by condensing uniformly the laser beam on a processing surface. CONSTITUTION: A scribing device of a light guide panel using laser includes a laser oscillator(110), a beam expander(120), a focus shift module(130), an object lens(140), a galvano scanner(150), and a controller(170). The beam expander(120) is used for expanding the output laser beam of the laser oscillator(110). The focus shift module(130) is used for shifting horizontally a focusing position of the laser beam of the beam expander(120). The object lens(140) is used for condensing the diverged laser beam of the focus shift module(130). The galvano scanner(150) is used for scanning the laser beam of the object lens(140) to an X-axis and a Y-axis of the predetermined region. The controller(170) controls the focus shift module(130) and the galvano scanner(150).

Description

Scribing apparatus for light guide panel and calibrating method

The present invention relates to a scribing apparatus for a light guide plate and a billboard using a laser and a method for correcting the same. More particularly, the present invention relates to a device for scribing using a CO2 laser and a method for correcting the light reflectance on one surface of the light guide plate. It is about.

Generally, a light guide plate used for a backlight and an advertisement display panel of an LCD includes a v-groove at its rear surface to evenly reflect light from a light source to the front side. 1 is a cross-sectional view schematically showing an example of a backlight using such a light guide plate. Referring to FIG. 1, a plurality of V-shaped groove portions 10a formed to reflect light to the front surface of the light guide plate 10 made of an acrylic plate having a predetermined thickness are formed. Fluorescent lamps are provided as light sources 12 on both sides of the light guide plate 10, and reflecting plates 14 are disposed around the fluorescent lamps. The reflecting plate 16 is disposed on the rear surface of the light guide plate 10 to assist the front reflection of the light. A diffuser 18 is arranged on the front surface of the light guide plate 10 to scatter light reflected to the front surface to uniformize the brightness of the light guide plate 10, and the prism 20 dividing and condensing light on the diffuser 18 to improve luminance. Is placed.

The v-shaped groove portion 10a formed on the rear surface of the light guide plate 10 is generally formed more densely away from the light source 12 and is formed more sparsely. In FIG. 1, the v-shaped grooves 10a are shown in one direction in order to be described. However, the v-shaped grooves 10a are generally formed at right angles.

2 is a view showing the configuration of a conventional laser processing apparatus. Referring to FIG. 2, the laser device includes a laser oscillation device 30, a galvano scanner 40 for scanning a laser beam oscillated from the laser oscillation device 30 in a XY direction to a predetermined region, and an incident laser beam. The beam has an f-theta lens 50 which forms a focal spot of the same size over the whole of the processing area. Reference numerals 41 and 42 reflect laser beams incident as x and y mirrors, respectively.

However, the f-theta lens 50 has a problem that it is difficult to apply to a large light guide plate and a processed plate of about 2000 mm because the processing area is limited to a maximum length of about 300 mm.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a light guide plate scribing apparatus using a laser that can be used in a large light guide plate and a processed plate, and a correction method thereof.

1 is a cross-sectional view schematically showing an example of a backlight using a light guide plate.

2 is a view showing the configuration of a conventional laser processing apparatus.

3 is a view schematically showing a scribing apparatus for a light guide plate and an advertisement board using a laser according to a preferred embodiment of the present invention.

4 is a view schematically showing an example of the horizontal movement means of the scanning lens of the focus movement module according to the present invention.

5 is a flowchart of a correction method of a scribing apparatus according to the present invention.

6 is a view schematically illustrating a distortion phenomenon by a general lens.

* Description of Signs of Major Parts of Drawings *

110: laser oscillator 120: beam expander

130: focus shift module 140: objective lens

150: galvano scanner 160: processing plate

170: control unit

In order to achieve the above object, a scribing apparatus for a light guide plate and an advertisement board using a laser of the present invention includes: a laser oscillation apparatus;

A beam expander for enlarging the laser beam oscillated from the laser oscillator;

A focus shift module for horizontally shifting the focusing position of the laser beam from the beam expander;

An objective lens for focusing the laser beam diverging from the focal shift module;

A galvano scanner which scans the laser beam from the objective lens in a predetermined area in the X-Y direction; And

And a control unit for controlling the focus movement module and the galvano scanner.

The focal shift module comprises: a scanning lens for determining a focal length of a laser beam irradiated from the galvano scanner to a processing surface; And

And means for moving the scanning lens in a horizontal direction.

In addition, the horizontal movement means,

A fixing member which fixes the lens to move the scanning lens in a horizontal direction;

A linear guide guiding the fixing member in a horizontal direction; And

One end of the stroke pipe is connected to the fixing member is preferably provided with an actuator for moving the fixing member horizontally on the linear guide.

On the other hand, the focus shift module,

As the lens moves in the direction approaching the objective lens, the focal length between the galvano scanner and the processing surface becomes longer.

In order to achieve the above object, a method of correcting a scribing apparatus for a light guide plate and an advertisement board using the laser of the present invention,

(a) equally distributing the scribe region to predetermined points;

(b) irradiating a laser beam with a predetermined power on each point;

(c) measuring a deviation between the irradiated point and a target point and correcting the deviation; And

(d) The laser beam is irradiated to the corrected point, and the focusing position z value is corrected by moving the scanning lens of the focus shift module so that the focus of the laser beam is focused on the processing surface at the corrected point. And measuring a horizontal position of the scanning lens at the focused focal length.

In the step (d), the focal length between the galvano scanner and the processing surface becomes longer as the lens of the focal shift module moves toward the objective lens.

Hereinafter, a scribing apparatus for a light guide plate and an advertisement board using a laser and a method of correcting the same will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of layers or regions illustrated in the drawings are exaggerated for clarity.

3 is a view schematically showing a scribing apparatus for a light guide plate and an advertisement board using a laser according to a preferred embodiment of the present invention.

Referring to FIG. 3, a scribing apparatus for a light guide plate according to a preferred embodiment of the present invention includes a laser oscillator 110 and a beam expander 120 for enlarging a laser beam oscillated from the laser oscillator 110. And a focus shift module 130 for horizontally shifting the focusing position of the laser beam from the beam expander 120, and an objective lens 140 for focusing the diverged laser beam from the focus shift module 130. And a galvano scanner 150 for scanning the laser beam from the objective lens 140 in the XY direction on the processing surface 160 of the predetermined region.

The laser oscillator 110 uses a CO2 laser capable of processing an acrylic plate used as a light guide plate. The 4 mm diameter output light oscillated from the laser oscillator 110 becomes an enlarged parallel light of 8 mm diameter through the beam expander 120. The 8 mm diameter magnified light is incident on the 9 mm diameter scanning lens 132 of the focus movement module 130. The beam passing through the scanning lens 132 passes through the lens 132 and enters the objective lens 140 in a laser light state that is focused and then diverged again. The incident laser beam is reflected by the x-y mirrors 151 and 152 of the galvano scanner 150 while converging again at the objective lens 140 to focus on the processing surface 160 to etch a predetermined pattern.

In the scribing apparatus of the light guide plate according to the present invention, the laser beam passing through the galvano scanner is irradiated to the workpiece through an f-theta lens. The laser beam is focused on the surface of the object by adjusting the focal length of the laser beam according to the processing area on the acrylic plate which is the animal.

As illustrated in FIG. 4, the focus shift module 130 includes a scanning lens 132 for determining a focal length of the laser beam irradiated onto the processing surface 160, and the lens 132 is moved in a horizontal direction. And a linear guide 134 for guiding the fixing member 133 in the horizontal direction, and one end of the stroke pipe 135a to the fixing member 133 so that the fixing member 133 is fixed. An actuator 135 is provided to move 133 horizontally on the linear guide 134. The lens 132 may be a convex lens or a concave lens that allows the incident laser beam to be incident to the objective lens of the next stage, and each lens may be a single lens or a composite lens.

The scribing apparatus of the present invention is provided with a control unit 170 for controlling movement of the x-y mirrors 151 and 152 and the scanning lens 132 of the galvano scanner 150. The control unit 170 controls the reflection position of the x-y mirrors 151 and 152 and the horizontal movement of the scanning lens 132 by data stored in predetermined software.

When the scanning lens 132 moves to the right in FIGS. 3 and 4, the focal length of the laser beam passing through the objective lens 140 becomes long, and thus the focusing distance of the scanning lens 132 can be focused on the edge of the processing surface 160. The vertical length z between the machining point of 160 and the galvano scanner is adjusted.

When the acrylic plate, which is a light guide plate, is to be processed by the scribing apparatus, the laser output must be stable and the etching position is precise for the entire processed surface in order to improve the appearance, brightness, and uniformity of the light guide plate. In order to satisfy this demand, the galvanoscanner 150 and the focus shift module 130 must be calibrated. This correction consists of the x-y axis correction, which is the plane through the galvano scanner 150, and the z axis correction, which is the focal length between the object point 140 and the machining point of the machining surface 160.

The focus correction method in the light guide plate using the scribing apparatus will be described in detail.

5 is a flowchart of a correction method of a scribing apparatus according to the present invention.

Referring to FIG. 5, first, a grid of a plurality of points is formed on a processing plate 160 or a sheet for replacing a processing plate on a processing table (not shown) (S1). For example, a 5 x 5 grid is formed to form 25 points (see Figure 6).

Subsequently, the laser beam is oscillated from the laser oscillator 110 and the laser beam is sequentially irradiated to the 25 points (S2). In this case, the laser beam from the fixed laser oscillator 110 generally contacts the processing surface 160 via the beam expander 120, the focus shift lens 130, the objective lens 140, and the galvano scanner 150. Barrel distortion and pin cushion as shown in FIG. In order to correct such irradiation point, the angles of the x 151 and the y mirror 152 of the galvano scanner 150 are corrected to perform a primary correction so that the laser beam is irradiated at a desired position, and the correction data is controlled. Transfer to the unit 170 (S3).

The x-y plane correction process is performed at each point, and when the plane correction process is completed, the process proceeds to the next step (S4).

Next, the laser beam is irradiated to the corrected point (S5). This time, the focal length is different for each point on the processing surface due to the constant focal length from the objective lens 140. Therefore, when the focal length is adjusted by moving the scanning lens 132 of the focus movement module 130 in the horizontal direction to match the focal length for each point, the position of the scanning lens 132 is measured at this time, and the measured data is measured. The control unit 170 transmits (S6). The focal length of the laser beam passing through the objective lens 140 becomes longer as the scanning lens 132 approaches the objective lens 140 on the linear guide 134.

When the z-axis correction process performed at each point is completed (S7), the correction process ends.

As described above, according to the scribing apparatus of the light guide plate and the billboard using the laser according to the present invention, not only a small light guide plate but also a large light guide plate having a length of about 2000 mm, the laser beam of the scribing apparatus is uniform at a focal length on the processing surface. The light guide plate is improved in appearance, brightness, and uniformity because it is controlled to form a light.

Although the present invention has been described with reference to the embodiments with reference to the drawings, this is merely exemplary, it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined only by the appended claims.

Claims (6)

Laser oscillation device; A beam expander for enlarging the laser beam oscillated from the laser oscillator; A focus shift module for horizontally shifting the focusing position of the laser beam from the beam expander; An objective lens for focusing the laser beam diverging from the focal shift module; A galvano scanner which scans the laser beam from the objective lens in a predetermined area in the X-Y direction; And And a control unit for controlling the focus movement module and the galvano scanner. The method of claim 1, wherein the focus shift module, A scanning lens for determining a focal length of the laser beam irradiated from the galvano scanner onto the processing surface; And And a means for moving the scanning lens in a horizontal direction. The method of claim 2, wherein the horizontal movement means, A fixing member which fixes the lens to move the scanning lens in a horizontal direction; A linear guide guiding the fixing member in a horizontal direction; And And a actuator connected to one end of a stroke pipe to the fixing member to move the fixing member horizontally on the linear guide. The method of claim 2, wherein the focus shift module, The scribing apparatus of the light guide plate and the billboard using a laser, characterized in that the focal length between the galvano scanner and the processing surface becomes longer as the lens moves in the direction approaching the objective lens. (a) equally distributing the scribe region to predetermined points; (b) irradiating a laser beam with a predetermined power on each point; (c) measuring a deviation between the irradiated point and a target point and correcting the deviation; (d) The laser beam is irradiated to the corrected point, and the focusing position z value is corrected by moving the scanning lens of the focus shift module so that the focus of the laser beam is focused on the processing surface at the corrected point. And measuring a horizontal position of the scanning lens at the focused focal length. The method of claim 5, wherein step (d) The scribing correction method of the light guide plate and the billboard using a laser, characterized in that the focal length between the processing surface from the galvano scanner is longer as the lens of the focusing module moves toward the objective lens.