KR101255286B1 - Apparatus for fabricating light guide panel and backlight unit having the light guide panel - Google Patents

Abstract

The present invention provides a light guide plate manufacturing apparatus capable of improving light efficiency and brightness, and a backlight unit having the light guide plate.
The backlight unit according to the present invention includes a light source for generating light; And guides the light incident from the light source, and emits the guided light upward, and an upper pattern formed on the front surface and a lower pattern formed on the rear surface to reflect or refract light and intersect the upper pattern. And a light guide plate, wherein the upper pattern is formed in a lenticular shape along a direction perpendicular to the length direction of the lower pattern, and a ratio of a height and a width of the upper pattern is formed in a range of 1/15 to 8/15. The pattern is formed in the shape of a round prism-shaped intaglio where two inclined surfaces meet, the angle of the inclined surface is 40 to 55 degrees, the length of the two inclined surfaces of the lower pattern is formed different, the length of the lower pattern Is longer than the width of the lower pattern.

Description

A manufacturing apparatus of a light guide plate, and a backlight unit having the light guide plate {APPARATUS FOR FABRICATING LIGHT GUIDE PANEL AND BACKLIGHT UNIT HAVING THE LIGHT GUIDE PANEL}

The present invention relates to an apparatus for manufacturing a light guide plate capable of improving light efficiency and brightness, and a backlight unit having the light guide plate.

In general, the liquid crystal display (Liquid Crystal Display) is a flat panel display device that displays an image using a liquid crystal, it is thinner and lighter than other display devices, and has the advantages of low driving voltage and low power consumption, It is widely used throughout.

Such a liquid crystal display device requires a backlight unit for supplying light because the liquid crystal display panel for displaying an image is a non-light emitting device that does not emit light by itself.

An ink pattern 16 is formed on the surface of the light guide plate 12 of the backlight unit by a printing method as shown in FIG. 1A. The ink pattern 16 scatters light that is totally reflected inside the light guide plate 12 and exits the light guide plate 12 to scatter or condense using the reflective sheet 14 or the diffusion sheet to increase luminance. In this case, due to the difference in refractive index between the light guide plate 12 and air, the emission angle of the light emitted from the light guide plate 12 is very high at 65 to 85 degrees, so that it is difficult to adjust the angle. In this way, the light distribution is adjusted so that the emission angle is high at 0 degree using a diffusion sheet and a prism sheet as shown in FIG.

As such, the conventional backlight unit has a problem in that it is difficult to control the light distribution only by the light guide plate 12, so that the light distribution may be changed depending on the diffusion sheet and the prism sheet, and the cost increases due to the diffusion sheet and the prism sheet. There is a problem that the entire thickness becomes thick.

In addition, since the ink pattern 16 formed on the conventional light guide plate 12 is formed very low at a height of several μm, it is difficult to control the emission angle of light.

In order to solve the above problems, the present invention is to provide a light guide plate manufacturing apparatus that can improve the light efficiency and brightness and a backlight unit having the light guide plate.

In order to achieve the above technical problem, the backlight unit according to the present invention includes a light source for generating light; And guides the light incident from the light source, and emits the guided light upward, and an upper pattern formed on the front surface and a lower pattern formed on the rear surface to reflect or refract light and intersect the upper pattern. And a light guide plate, wherein the upper pattern is formed in a lenticular shape along a direction perpendicular to the length direction of the lower pattern, and a ratio of a height and a width of the upper pattern is formed in a range of 1/15 to 8/15. The pattern is formed in the shape of a round prism-shaped intaglio where two inclined surfaces meet, the angle of the inclined surface is 40 to 55 degrees, the length of the two inclined surfaces of the lower pattern is formed different, the length of the lower pattern Is longer than the width of the lower pattern.

Here, the lower pattern is characterized in that it is formed to have a flat surface by irradiating the compressed plate with a laser.

The lower pattern has a length of 600 to 800 μm, a width of 50 to 300 μm, and a height of 50 to 150 μm.

In particular, the inclined surface of the lower pattern is arranged in the form perpendicular to the traveling direction of the light in the light guide plate, the longitudinal direction of the lower pattern is characterized in that formed in parallel with the array direction of the light source.

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On the other hand, the lower patterns are characterized in that the density is increased as the distance from the light source.

Specifically, when the light source is located on one side of the light guide plate, the interval between the lower patterns is narrowed toward the light guide part of the light guide plate from the light receiving part of the light guide plate, and when the light sources are located on both sides of the light guide plate, The interval between the patterns may be narrowed toward both sides of the light guide plate from both sides of the light guide plate.

In order to achieve the above technical problem, the light guide plate manufacturing apparatus according to the present invention for guiding the light incident from the light source, and emits the guided light upward, the upper pattern forming portion for forming an upper pattern on the front surface of the light guide plate Wow; And a laser processing machine that reflects or refracts light by irradiating a laser on the rear surface of the light guide plate to form a lower pattern that intersects the upper pattern, wherein the upper pattern has a lenticular shape along a direction perpendicular to a length direction of the lower pattern. The height and width ratio of the upper pattern is formed of 1/15 ~ 8/15, the lower pattern is formed in the intaglio pattern of the rounded prism-shaped prismatic angle where the two inclined surfaces meet, the angle of the inclined surface Is 40 to 55 degrees, and the lengths of the two inclined surfaces of the lower pattern are different, and the length of the lower pattern is longer than the width of the lower pattern.

The upper pattern forming unit may be an extrusion roller or an imprint mold having a groove having an inverted shape with the upper pattern.

The present invention includes a light guide plate having a lower pattern of a round prism shape formed by a laser processing process and an upper pattern of an embossed shape formed by an extrusion process. Accordingly, the present invention can improve the luminance of the backlight unit by 15% or more than the conventional light guide plate alone without the prism sheet and the diffusion sheet by adjusting the oblique angle of the lower pattern. Accordingly, the backlight unit according to the present invention does not require the prism sheet and the diffusion sheet, so that the cost can be reduced and the weight can be reduced.

In addition, the oblique surface of the lower pattern according to the present invention is formed flat, reflecting or refracting the light and proceeding the light toward the upper pattern, it is possible to obtain a uniform brightness compared to the method of scattering the light to proceed to the upper pattern.

1A is a cross-sectional view illustrating a conventional backlight unit, and FIG. 1B is a view for explaining a light distribution adjusting process using a conventional diffusion sheet and a prism sheet.
2 is a perspective view illustrating a backlight unit according to the present invention.
3 is a perspective view illustrating an upper pattern and a lower pattern illustrated in FIG. 2.
4A and 4B are cross-sectional views illustrating the backlight unit cut along the lines "I-I '" and "II-II'".
5 is a diagram illustrating a backlight unit according to the present invention, which is dividedly driven.
6 is a perspective view illustrating in detail the lower pattern of the backlight unit according to the present invention.
FIG. 7 is a cross-sectional view illustrating the inclined angle of the lower pattern illustrated in FIG. 6.
8A to 8C illustrate various embodiments of the lower pattern illustrated in FIG. 3.
9A to 9C are views for explaining the inclination angle, width, length, and the like of the lower pattern according to the present invention controlled by the process conditions of the laser processing process.
10 is a view showing the luminance characteristics compared to the viewing angle emitted from the light guide plate according to the present invention.
11A and 11B are diagrams illustrating a first embodiment of a method of manufacturing a light guide plate according to the present invention.
12A to 12C are diagrams illustrating a second embodiment of a method of manufacturing a light guide plate according to the present invention.
13 is a cross-sectional view showing a light guide plate formed of a conventional casting plate.
FIG. 14 is a perspective view illustrating a liquid crystal display including the backlight unit illustrated in FIG. 2.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings and embodiments.

2 is a perspective view illustrating a backlight unit according to the present invention.

The backlight unit 110 illustrated in FIG. 2 includes a light source 120, a light guide plate 130, and a reflective sheet 160.

The light source 120 is mounted on the light source circuit board 140 to be driven by receiving power from the outside to generate light. The light source 120 is formed to face the incident surface of the light guide plate 130. The light source 120 is formed of any one of a light emitting diode (LED), a cold cathode fluorescent lamp (CCFL), and an external electrode fluorescent lamp (EEFL). The light emitted from the light source 120 is directly incident into the light guide plate 130 or reflected by a light source housing (not shown) formed to surround the light source 120 and then enters the light guide plate 130.

The reflective sheet 160 is disposed below the light guide plate 130 and reflects the light emitted from the light source 120 to the outside through the rear surface of the light guide plate 130 toward the light guide plate 130.

The light guide plate 130 is disposed to face the light source 120 to guide the light incident from the light source 120, and diffuses and condenses the light guided by the light guide plate 130 to the front of the light guide plate 130. As shown in FIG. 3, the light guide plate 130 includes a base layer 132, an upper pattern 134, and a lower pattern 136. The base layer 132, the upper pattern 134, and the lower pattern 136 are formed to be integrated with the same material. For example, the base layer 132, the upper pattern 134 and the lower pattern 136 is formed of an extruded plate material that melts upon laser irradiation.

The base layer 132 guides the light incident from the light source 120 to spread evenly therein.

The upper pattern 134 collects light guided by the base layer 132 and emits light collected by the upper part to the top. To this end, a plurality of upper patterns 134 are formed in the form of a lenticular lens as shown in FIGS. 4A and 4B, and are arranged along an arrangement direction of the light source 120, that is, the X-axis direction. The upper pattern 134 improves luminance by setting the light distribution plate of the light guide plate 130 in a direction perpendicular to the arrangement direction of the upper pattern 134, that is, in the Z-axis direction.

Since the light incident on the light guide plate 130 by the upper pattern 134 proceeds along the longitudinal direction of the upper pattern 134, split driving of the light guide plate 130 becomes possible. That is, the light guide plate 130 is divided into a plurality of light guide regions A1, A2, and A3 as shown in FIG. 5 to separately drive the liquid crystal display panel positioned on the front surface of the backlight unit.

In addition, the ratio of the height of the upper pattern 134 and the width of the upper pattern 134 is formed from 1/15 to 8/15. When the above conditions are satisfied, the light guide plate 130 is reduced since the light incident to the light incidence portion of the light guide plate 130 exits to the light guide portion of the light guide plate 130 in comparison with a conventional light guide plate that breaks the total reflection condition and emits light. It is possible to increase the amount of light emitted to the light exit portion of the. If the height is higher than the above condition without satisfying the above condition, the effect of increasing the amount of emitted light is insufficient.

The lower pattern 136 is formed in a direction crossing the upper pattern 134 as shown in FIG. 6. As shown in FIG. 7, the lower pattern 136 is engraved on the back surface of the light guide plate 130, that is, in the form of a prism having a rounded vertex.

The lower patterns 136 are formed in a zigzag form as shown in FIG. 6 at regular intervals or a plurality of lower patterns 136 in a line as shown in FIG. 8A.

In addition, the lower pattern 136 is formed to have a higher density as it moves away from the light source 120. That is, when the light source 120 is located at one side of the light guide plate 130 as shown in FIG. 8B, the density of the lower patterns 136 is gradually increased from the light incident part of the light guide plate 130 to the light guide part of the light guide plate 130. Increases. Accordingly, the distance between the lower patterns 136 adjacent to the light guide portion of the light guide plate 130 is smaller than the distance between the lower patterns 136 adjacent to the light incident portion of the light guide plate 130 (d1 <d2).

As illustrated in FIG. 8C, when the light sources 120 are positioned at both sides of the light guide plate 130, the density of the lower patterns 136 increases from both sides of the light guide plate 130 toward the center of the light guide plate 130. Accordingly, the distance between the lower patterns 136 positioned at the center of the light guide plate 130 is smaller than the distance between the lower patterns 136 adjacent to the light incident portions on both sides of the light guide plate 130 (d1 <d2).

As described above, the light traveling along the longitudinal direction of the upper pattern 132 by the lower pattern 136, the density of which increases as it moves away from the light source 120, may be formed on a surface other than the exit surface of the light guide plate 130. , Light loss to the light exiting unit) can be prevented.

The lower pattern 136 is formed through a machining process using a laser processing machine. At this time, the angle (θ) of the oblique plane of the lower pattern 136, the length L of the lower pattern 136 and the width W of the lower pattern 136 are the focal position of the laser, the processing head movement time, the laser output And adjusting the aperture and focal length of the lens. In particular, as shown in FIG. 9A, the angle of the inclined surface of the lower pattern 136 may be adjusted by changing laser processing conditions. Here, the angle θ of the inclined surface is formed at 40 to 55 degrees such that the luminance component perpendicular to the light guide plate 130 is maximized, and the angle formed between the inclined surface of the lower pattern 136 and the rear surface of the light guide plate 130 is 135 to 140. Road is formed. The lengths of the oblique planes adjacent to each other are the same or different.

In addition, the length L of the lower pattern 136 is longer than the width W, as shown in FIG. 9B. For example, the length L of the lower pattern 136 is formed to 600 ~ 800㎛, the width W is formed of 50 ~ 300㎛, the height (H) is formed of 50 ~ 150㎛.

The lower pattern 136 is formed through a laser processing process, so that the oblique surface of the lower pattern 136 has a smooth and flat surface as shown in 9c.

Accordingly, light incident from the light source 120 to the light guide plate 130 and guided by the base layer 132 is reflected or refracted by the oblique surface of the lower pattern 136, and the reflected or refracted light is reflected by the upper pattern 134. To the side.

10 is a view showing the luminance characteristics compared to the viewing angle emitted from the light guide plate according to the present invention.

As shown in FIG. 10, the emission angle of the light guide plate 130 according to the present invention is maximum at a viewing angle of 0 degrees (perpendicular to the front surface of the light guide plate 130) similar to that of a backlight unit having a conventional diffusion sheet and a prism sheet. The luminance distribution is shown. As such, the light guide plate according to the present invention exhibits a maximum luminance distribution at a viewing angle of 0 degrees even without the conventional diffusion sheet and prism sheet, thereby reducing the purchase cost of the diffusion sheet and prism sheet, and reducing the overall thickness of the backlight unit. It becomes possible. In addition, the light guide plate 130 according to the present invention has an average brightness improvement of 15% or more compared to a backlight unit in which two diffusion sheets are stacked on a conventional light guide plate.

11A and 1B are views for explaining a first embodiment of a method of manufacturing a light guide plate according to the present invention.

As shown in FIG. 11A, the extrusion roller 150 having the concave lens-shaped groove 152 is aligned on the extruded sheet material 138 that is melted during the laser processing process such as polymethylmethacrylate (PMMA). do. Then, the compression roller 150 is rotated on the compression plate 138 to form the upper pattern 136 in the form of a lenticular lens. The compressed plate 138 on which the upper pattern 136 is formed is conveyed toward the laser machine through a metal belt (not shown). Thereafter, as shown in FIG. 11B, the lower pattern 136 is formed by irradiating a laser on the back surface of the extruded sheet material 138 using a laser processing machine including the laser generator 154 and the processing head 156.

Specifically, the laser generation unit 154 made of CO ₂ laser oscillates the laser beam. The laser beam oscillated by the laser generating unit 154 is incident to the processing head 156 consisting of a mirror and a focusing lens, and the processing head 156 irradiates a laser beam on the back surface of the extruded sheet material 138 while moving up, down, left, and right. As a result, the lower pattern 136 is formed. Here, the movement time of the processing head 156 is 1-4 m / s, for example, and the output of a laser beam is 100-400W.

12A to 12C are diagrams for describing a second embodiment of a method of manufacturing a light guide plate according to the present invention.

As shown in FIG. 12A, an imprint mold 158 having a concave lens-shaped groove is aligned above the extruded plate member 138. As shown in FIG. 12B, the extruded plate member 138 is pressed using the imprint mold 158 to form a groove of the imprint mold 158 and an upper pattern 134 in the form of a reverse lenticular lens.

Then, as shown in FIG. 12C, the lower pattern 136 is formed by irradiating a laser on the back surface of the extruded sheet material 138 using a laser processing machine including the laser generating unit 154 and the processing head 156.

On the other hand, the compressed plate material of the light guide plate 130 according to the present invention has a molecular weight of about 10 times lower than that of the casting plate of the conventional light guide plate. In this case, the casting plate having a relatively high molecular weight does not perform heat transfer properly, so that the laser energy irradiated to the casting plate is not properly transformed into thermal energy so that the surface of the lower pattern 18 is roughly formed as shown in FIG. 13. Accordingly, since the light guide plate 12 formed of the conventional casting plate is scattered by the lower pattern 18, it is difficult to control the emission angle, and in the region where the surface scattering is severe, the light output is large and the uniform luminance can be obtained. none.

On the other hand, in the compressed plate having a relatively low molecular weight, heat transfer is uniformly transmitted compared to the casting plate, so that the laser energy irradiated onto the compressed plate is uniformly transformed into thermal energy, thereby forming a smooth and flat surface of the lower pattern 136. Accordingly, since the light is reflected or refracted by the oblique surface of the lower pattern 136 having a flat surface, the emission angle can be easily adjusted to obtain uniform luminance.

FIG. 14 is a perspective view illustrating a liquid crystal display including the backlight unit illustrated in FIG. 2.

The liquid crystal display illustrated in FIG. 14 includes a backlight unit and a liquid crystal panel 170.

The backlight unit is disposed under the liquid crystal panel 170 and provides light to the liquid crystal panel 170. To this end, the backlight unit includes a light source 120, a light guide plate 130, and a reflective sheet 160 as shown in FIG. 2. Here, the exit angle of the light guide plate 130 of the backlight unit of the present invention is 0 degrees perpendicular to the exit surface of the light guide plate 130 as shown in FIG. 10 without the prism sheet and the diffusion sheet. Accordingly, since the backlight unit according to the present invention does not require an optical sheet such as a conventional prism sheet and a diffusion sheet positioned on the light guide plate 130, cost can be reduced.

The liquid crystal panel 170 is disposed above the backlight unit and is mounted on the support main 180. Here, the liquid crystal panel 170 may be fixed on the supporter main 180 by the top cover 190 fastened to the supporter main 180 through hooks and / or screws. Here, the supporter main 180 may not only seat the liquid crystal panel 170 but also accommodate the backlight unit.

The liquid crystal panel 170 implements an image by using light emitted through the light guide plate 130. To this end, the liquid crystal panel 170 may include a color filter substrate 172 and a thin film transistor substrate 174 facing each other with the liquid crystal interposed therebetween. The gate line formed on the thin film transistor substrate 174 is driven by the gate signal generated by the gate driver integrated circuit 184 mounted on the gate tape carrier package (TCP) 186. The data line formed on the thin film transistor substrate 174 is driven by the data signal generated by the data driver integrated circuit 182 mounted on the data tape carrier package 178. In addition, the data tape carrier package 178 is attached to a printed circuit board 176 on which a timing controller, a power supply unit, and various circuits are mounted, and supplies various signals necessary for implementing an image to the gate drive integrated circuit 184 and the data drive integrated circuit ( 182).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

110: backlight unit 120: light guide plate
130: Light guide plate 132: Base layer
134: upper pattern 136: lower pattern
160: reflective sheet

Claims (10)

A light source for generating light;
And guides the light incident from the light source, emits the guided light upwards, an upper pattern formed on the front surface, and a lower pattern formed on the rear surface to reflect or refract the light and intersect the upper pattern. With a light guide plate to
The upper pattern is formed in a lenticular shape along a direction perpendicular to the length direction of the lower pattern, the ratio of the height and width of the upper pattern is formed of 1/15 ~ 8/15,
The lower pattern is formed in an intaglio pattern having a rounded prism shape in which two inclined surfaces meet each other, and the inclination angle is 40 to 55 degrees.
The length of the two oblique sides of the lower pattern is formed differently,
The length of the lower pattern is a backlight unit, characterized in that longer than the width of the lower pattern. The method of claim 1,
The lower pattern is a backlight unit, characterized in that formed to have a flat surface by irradiating the compressed plate with a laser. The method of claim 1,
The length of the lower pattern is formed of 600 ~ 800㎛, the width is formed of 50 ~ 300㎛, the backlight unit, characterized in that the height is formed of 50 ~ 150㎛. The method of claim 1,
And the oblique surface of the lower pattern is arranged in a direction perpendicular to the traveling direction of the light in the light guide plate, and the length direction of the lower pattern is formed in parallel with the arrangement direction of the light source. delete The method of claim 1,
And the lower patterns are formed to have a higher density as they move away from the light source. The method according to claim 6,
When the light source is located on one side of the light guide plate, the interval between the lower patterns becomes narrower from the light incident part of the light guide plate toward the light guide part of the light guide plate,
When the light source is located on both sides of the light guide plate, the interval between the lower patterns is narrowed toward both sides of the light guide plate toward the center of the light guide plate. In the manufacturing apparatus of the light guide plate which guides the light incident from the light source and emits the guided light upwards,
An upper pattern forming unit forming an upper pattern on the front surface of the light guide plate;
It is provided with a laser processing machine for reflecting or refracting light by irradiating a laser on the back surface of the light guide plate to form a lower pattern crossing the upper pattern,
The upper pattern is formed in a lenticular shape along a direction perpendicular to the length direction of the lower pattern, the ratio of the height and width of the upper pattern is formed of 1/15 ~ 8/15,
The lower pattern is formed in an intaglio pattern having a rounded prism shape in which two inclined surfaces meet each other, and the inclination angle is 40 to 55 degrees.
The length of the two oblique sides of the lower pattern is formed differently,
The length of the lower pattern is longer than the width of the lower pattern manufacturing apparatus of the light guide plate. The method of claim 8,
The lower pattern is formed to have a flat surface by irradiating the compressed plate with a laser, and the inclined surface of the lower pattern is arranged in a direction perpendicular to the traveling direction of the light inside the light guide plate, and the longitudinal direction of the lower pattern is An apparatus for manufacturing a light guide plate, characterized in that formed in parallel with the array direction. The method of claim 8,
The upper pattern forming unit is an extrusion roller or an imprint mold having a groove of the upper pattern and the inverted shape, the manufacturing apparatus of the light guide plate.

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