KR100396434B1 - Pattern forming apparatus for light guide panel - Google Patents

Abstract

A pattern forming apparatus for a light guide plate is disclosed. The present invention is a laser oscillation unit for outputting a laser beam for scanning the upper surface of the light guide plate to form a plurality of patterned light guide pattern portion by laser beam processing on the light guide plate; and to prevent the light guide plate from warping by the heat of the laser beam A deflection prevention means installed; and an absorption scattering prevention means installed to remove smoke generated while the light guide pattern portion is formed on the light guide plate, wherein the light guide plate is bent due to local heat generated during scanning with a laser beam on the light guide plate. This makes it possible to form each pattern of the light guide pattern portion at a desired position, thereby reducing the defective rate.

Description

Pattern forming apparatus for light guide plate {Pattern forming apparatus for light guide panel}

The present invention relates to a light guide plate, and more particularly, to a pattern forming apparatus for a light guide plate which prevents deformation of the light guide plate when forming the light guide pattern portion using a laser beam on the light guide plate.

In general, a light guide panel is a plate that provides a path for uniformly scattering and diffusing light emitted from a light source, and is used for a light receiving type flat panel display device such as a liquid crystal display device or a surface light source device used for an illumination signboard. Included.

As the surface light source device, a cold cathode fluorescent lamp (CCFL) or a method of disposing a LED and a flat fluorescent lamp method in which a phosphor-coated substrate is assembled are widely used. Cold cathode fluorescent lamps may be classified into an edge light method using a light guide plate and a direct light method overlapping on a plane according to the arrangement of the light source on the display surface.

1 illustrates a conventional light guide plate and a reflecting plate, and FIG. 2 illustrates a part of a surface light source device to which a conventional edge light emission method is applied.

1 and 2, the surface light source device 10 includes a light guide plate 11 and a reflection plate 12 disposed below the light guide plate 11. At least one light source 13 is provided on the sidewall of the light guide plate 11. As the light source 13, a cold cathode fluorescent lamp or an LED is used. The light source 13 is wrapped by the cover member 14. Meanwhile, a diffusion plate, a prism sheet, or the like may be provided on the light guide plate 11.

In the surface light source device 10 having such a structure, the light irradiated from the light source 13 is irradiated to the light guide plate 11, and the light guided to the light guide plate 11 is relatively uniform in each part by the reflecting plate 12. Reflected upwards with a single illuminance, this light diffuses forward through a diffuser plate or prism sheet.

In this case, a plurality of light guide patterns 15 are formed in the light guide plate 11 to more effectively scatter and diffuse light incident from the light source 13. That is, the light guide pattern portion 15 is formed on the bottom surface of the light guide plate 11 made of a transparent acrylic resin using an ink including a bead-shaped TiO ₂ and glass or an acrylic material. The light guide pattern portion 15 is formed by printing by applying ink onto a mask having a corresponding pattern.

In this printing method, the light source 13 is positioned on the sidewall of the light guide plate 11 so that the incident light is scattered, reflected, and diffused by each pattern of the printed light guide pattern portion 15 to have a relatively uniform luminance. This is possible.

However, the formation of the light guide pattern portion 15 using the printing method has the following problems.

The manufacturing and printing process of the ink, which is the raw material of the light guide pattern portion 15, is complicated, and the yield rate is low due to high defect rate such as dropping or staining of each pattern of the printed light guide pattern portion 15. Unused light guide plates cannot be reused, which increases manufacturing costs.

As an alternative, a light guide pattern portion having a predetermined pattern was formed on the light guide plate by laser processing. That is, the laser processing method is a method of forming a light guide pattern portion by scanning a laser beam oscillated from a laser device on a light guide plate. This method can prevent the dropping or staining of each pattern of the light guide pattern part by the printing method, and can overcome the difficulty of forming a fine pattern.

However, the formation of the light guide pattern portion according to the conventional laser processing method has the following problems.

When using a laser device, the laser beam should be irradiated at a position perpendicular to the processing surface of the light guide plate. To this end, the laser device is linearly reciprocated along the X and Y axes of the light guide plate using the XY stage to move its position.

Since the XY stage is processed by linearly reciprocating the XY stage, the larger the light guide plate is, the longer it takes for the reciprocating motion to increase the processing time of the light guide pattern portion. In addition, as the XY stage is mechanically driven, the accuracy is reduced when a fine pattern is required.

On the other hand, when irradiating a laser beam onto the light guide plate, the temperature of the focus portion irradiated with the laser beam and the adjacent region is increased, and it is necessary to adjust the heating time in order to obtain a desired line width. When the heating time is locally increased, warpage of the light guide plate occurs. Such warpage occurs a lot along the edges, and when such warpage occurs, the angle of incidence of the laser beam reaching the light guide plate is changed, making it difficult to form each pattern in a precise light guide pattern portion. In addition, the smoke generated during the formation of the light guide pattern portion reduces the energy of the laser beam.

The present invention is to solve the problems described above, to form a light guide pattern portion for scanning the laser beam in the state of maintaining the horizontal level of the light guide plate to cause the scattering and diffusion of light, productivity and uniformity of brightness and chromaticity It is an object of the present invention to provide a pattern forming apparatus for a light guide plate having an improved structure to improve the efficiency.

1 is an exploded perspective view showing a conventional light guide plate and a reflecting plate,

2 is a cross-sectional view schematically showing a conventional surface light source device;

3 is an exploded perspective view showing a surface light source device according to an embodiment of the present invention;

4 is a cross-sectional view schematically showing a part of FIG. 3;

Figure 5 is a schematic diagram showing a system for forming a light guide pattern portion according to an embodiment of the present invention.

<Brief description of symbols for main parts of the drawings>

10,30 ... plane light source device 11,31 ... light guide plate

12,32 ... reflective plate 13,33 ... light source

14,34 ... cover member 15,35 ... light guide pattern

51 Pattern control unit 52 Control unit

53 ... laser scanning mirror 54 ... laser oscillation

55 Lens section 510 Frame

520 Vacuum part 530 Heating part

540 .. Ventilation part 55 ... Exhaust part

In order to achieve the above object, the light guide plate pattern forming apparatus according to the aspect of the present invention,

A light guide plate pattern forming apparatus for forming a plurality of patterned light guide pattern portions by laser beam processing on a light guide plate,

A laser oscillator for outputting a laser beam scanning the upper surface of the light guide plate;

Warpage preventing means provided to prevent the light guide plate from being bent by the heat of the laser beam; And

And absorption scattering preventing means installed to remove smoke generated while the light guide pattern portion is formed on the light guide plate.

The bending preventing means may include a frame on which the light guide plate is mounted, and a vacuum unit configured to provide a vacuum force to form a vacuum passage in the frame and to vacuum the lower surface of the light guide plate with respect to the frame.

In addition, the frame is characterized in that the heating is electrically connected to the heat transfer to the light guide plate by applying heat thereto.

In addition, the absorption scattering prevention means is installed on one side of the light guide plate, characterized in that it comprises a blower for blowing the smoke by supplying a gas of normal pressure or more from the blower tube.

Further, the other side of the light guide plate is characterized in that the exhaust portion is further installed to remove the smoke generated by the light guide pattern portion formed on the light guide plate or the smoke blown from the blower.

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

3 illustrates a surface light source device 30 according to an embodiment of the present invention, and FIG. 4 illustrates a state in which the surface light source device 30 of FIG. 3 is coupled.

3 and 4, the surface light source device 30 is provided with a light guide plate 31 having a light guide pattern portion 35 formed on one surface thereof. A reflecting plate 32 for reflecting light upward is provided below the light guide plate 31. At least one sidewall of the light guide plate 31 is installed and a light source 33 for irradiating light to the light guide plate 31 is mounted. As the light source 33, a cold cathode fluorescent lamp or an LED is used. The light source 33 is surrounded by a cover member 34 having a reflective film formed so that light irradiated in the opposite direction of the light guide plate 31 is incident on the light guide plate 31 again. A diffusion plate 36 is disposed on the light guide plate 31 to scatter and diffuse light forward.

At this time, the light guide pattern portion 35 is formed in a predetermined pattern on the lower surface of the light guide plate 31, and can be processed into grooves of a dot type, a straight type, or a mixed type of a combination of a dot type and a straight type as shown. have. In addition, it may be processed into a square or lattice, or a groove by a combination of these shapes.

In addition, since the light guide pattern part 35 is processed according to the deflection angle of the laser beam according to the relative position between the laser system and the light guide plate 31 to be described later, each pattern of the light guide pattern part 35 emits light. It is asymmetrical so as to effectively reflect and scatter, and it will be advantageous that each pattern gradually increases as it moves away from the light source 33 to prevent a decrease in luminance.

On the other hand, on the upper surface of the light guide plate 31 may further form a light diffuser made of fine scratches so that light (arrow) irradiated from the light source 33 can be uniformly diffused to the front surface of the light guide plate 31.

According to a feature of the present invention, each pattern of the light guide pattern portion 35 formed on one surface of the light guide plate 31 is formed by scanning a laser beam using a laser system, and the light guide plate 31 due to local heating during scanning ) Is provided to prevent bending and to prevent absorption or scattering of the laser beam.

5 shows a system for forming the light guide pattern portion 35 of the present invention.

Referring to the drawings, the pattern system includes a pattern design unit 51, a control unit 52, a laser oscillation unit 53, a laser scan mirror unit 54, a lens unit 55, and a light guide plate 31. It includes a bending preventing means for preventing the warp, and absorption scattering prevention means for preventing the absorption or scattering phenomenon of the laser beam.

More detailed description is as follows.

The data input to the pattern design unit 51 for the design rule of each pattern of the light guide pattern part 35 to be formed on the light guide plate 31 is matched to the coordinate values of each pattern through the control unit 52 ( The position signal corresponding to the area to be scanned on one surface of 31 is transmitted to the laser scan mirror unit 53.

The pulse signal synchronized to the frequency of the laser scan mirror 53 is sent to the laser oscillator 54 through the controller 52, and the pattern of the light guide plate 31 is formed from the laser oscillator 54. The laser beam is output toward the region.

At this time, the laser scan mirror 53 is coupled to the reflector 53b on the axis of the galvanometer (53a) to the micro-rotation left and right or mutually in accordance with the position signal transmitted from the control unit 52. . Accordingly, when the signal for the region where the pattern is to be formed on the light guide plate 31 is received, it is possible to adjust the direction of the laser beam. The galvanometer 53a controls a rotation angle and a direction by installing a mechanism such as a coil on a rotation shaft, and when the current is cut off, the rotation shaft returns to its original position by the restoring force of the coil.

In this way, the laser beam oscillated from the laser oscillator 54 is changed in the traveling direction by at least one reflector 53b whose position is changed by the minute drive of the galvanometer 53a, and the lens unit 55 is moved. The light guide pattern part 35 is formed by scanning the area of the light guide plate 31 through which the pattern is formed.

Here, the light guide plate 31 may cause warpage when the laser beam is locally heated during scanning. The warpage occurs a lot along the edges, in particular, which makes it difficult to form the pattern in the desired position. In order to prevent such warpage, the light guide plate 31 is provided with warpage preventing means.

That is, the frame 510 supporting the light guide plate 31 is installed. The frame 510 is provided with a vacuum part 520 to completely contact the bottom surface of the light guide plate 31, that is, the surface opposite to the region where the light guide pattern part 35 is to be formed.

The vacuum part 520 is provided with a vacuum passage part 521 through the inside of the frame 510. The vacuum part 520 is inhaled by a pumping force such as a rotary pump through the vacuum passage part 521 to allow the frame 510 to be sucked. With respect to the light guide plate 310, it is possible to vacuum suction. In this case, in order to prevent scratches on one surface of the light guide plate 31, a vacuum pad 522 may be further installed on the path of the vacuum passage part 521. In addition, the light guide plate 31 may be coupled to the frame 510 by mechanical means such as clamping or joint fixing.

When the adhesion of the light guide plate 31 to the frame 510 is not sufficient even when scanning the laser beam output from the laser oscillator 54 while maintaining the horizontal degree of the light guide plate 31, the light guide plate 31 is By eliminating the temperature difference between the upper and lower surfaces, the bending phenomenon can be further prevented.

That is, a heating unit 530, for example, a heating wire 531, is installed inside or outside the frame 510 to generate heat, or heat is generated by ultrasonic waves to heat the frame 510. Heat may be transferred to the light guide plate 31. When the frame 510 is heated, the heat is transferred from the frame 510 to the lower surface of the light guide plate 31 by a temperature rising due to the laser beam scanned on the upper surface of the light guide plate 31. Can be eliminated.

In addition, since the etching method by scanning the laser beam on the light guide plate 31 is to evaporate the surface of the light guide plate 31 made of acrylic resin with strong energy, smoke (s) is generated due to the removed acrylic resin material. Done. Such smoke may cause absorption or scattering of the laser beam during the scanning process of forming the light guide pattern part 35 on the light guide plate 31 to reduce energy of the laser beam, thereby preventing processing of a desired pattern. .

In order to prevent such a phenomenon, a blower 540 may be selectively installed at one side of the light guide plate 31 to blow smoke generated. The blower 540 injects a gas having a normal pressure or higher to supply it to the surface of the light guide plate 31 through the blower pipe 541. The blower 540 removes smoke and simultaneously serves to cool the upper surface of the light guide plate 31.

In addition, an exhaust unit 550 is installed to remove the smoke removed by the blower 540. The exhaust part 550 may suck and discharge smoke of the acrylic resin evaporated from the surface of the light guide plate 31 to prevent absorption or scattering of the laser beam due to the smoke.

As such, the light guide pattern portion 35 formed on the light guide plate 31 adjusts the position of the reflector 53b of the laser scan mirror portion 53 relative to the laser oscillation portion 54, thereby directing the laser beam to the light guide plate 31. ) Is formed by scanning the area to be formed.

In this case, in order to prevent local bending of the light guide plate 31 due to the laser beam, a vacuum unit 520 is installed on the frame 510 from the lower portion thereof to vacuum-adsorb the light guide plate 31 to the frame 510. . In some cases, the heating unit 530 may be electrically connected to the frame 510 to apply heat to reduce the top and bottom temperature variations of the light guide plate 31.

In addition, the smoke generated when the raw material of the light guide plate 31 pattern portion, which is removed when the light guide pattern portion 35 is formed, is blown at normal pressure gas from the blower 54 provided on one side of the light guide plate 31. It is possible to inhale and discharge it from the exhaust part 550 to remove it.

As a result, on the light guide plate 31, it is possible to form the light guide pattern portion 35 made of a dot, a straight line, a mixture of a dot and a straight line, or a groove of a desired shape in a fine pattern.

As described above, the light guide plate pattern forming apparatus according to the present invention can obtain the following effects.

First, the local heat generated during scanning with a laser beam on the light guide plate prevents the light guide plate from warping, thereby making it possible to form each pattern of the light guide pattern portion at a desired position, thereby reducing the defective rate.

Second, due to the smoke generated during the formation of the light guide pattern portion, absorption and scattering of the laser beam may occur, thereby preventing the reduction of the energy of the laser beam.

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

Claims (5)

A light guide plate pattern forming apparatus for forming a plurality of patterned light guide pattern portions by laser beam processing on a light guide plate, A laser oscillator for outputting a laser beam scanning the upper surface of the light guide plate; Warpage preventing means provided to prevent the light guide plate from being bent by the heat of the laser beam; And And an absorption scattering preventing means installed to remove smoke generated while the light guide pattern portion is formed on the light guide plate. The method of claim 1, The bending preventing means includes a frame on which the light guide plate is mounted, and a vacuum unit configured to provide a vacuum force to form a vacuum passage in the frame and to vacuum suction the lower surface of the light guide plate to the frame. Device. The method of claim 2, And a heating part electrically connected to the frame to transfer heat to the light guide plate by applying heat thereto. The method of claim 1, The absorption scattering prevention means is installed on one side of the light guide plate pattern forming apparatus for a light guide plate, characterized in that it comprises a blower for blowing the smoke by supplying a gas of normal pressure or more from the blower tube. The method of claim 4, wherein The other side of the light guide plate pattern forming apparatus for the light guide plate, characterized in that the exhaust portion is further installed to remove the smoke generated by forming the light guide pattern portion on the light guide plate, the smoke blown from the blower.