KR20120067777A - Light guide plate and manufacturing method thereof - Google Patents

Abstract

The present invention is a light guide plate and a method for manufacturing the point light source or a line light source, and is formed on at least one side of both sides of the light guide plate, and the incident light and the incident light incident from the light source is changed to the surface light source and emitted It includes a light-emitting portion, the light-receiving portion wraps the light source, and the light guide plate formed in the shape of the upper and lower portions are larger than the cross-sectional area in the thickness direction of the light-emitting portion provides a method and a manufacturing method thereof.

Description

Light guide plate and manufacturing method thereof

The present invention relates to a light guide plate and a method of manufacturing the same.

Passive display devices such as liquid crystal display devices require a backlight unit. The backlight unit is divided into an edge method and a direct method according to the installed position.

The direct method is to direct light on the front of the display panel by arranging a plurality of lamps in a row on the lower surface of the diffusion plate. Such a direct method is used in a large screen display device that requires high brightness because the light utilization efficiency is higher than that of the edge method.

In the edge method, a light source is disposed on the side of the light guide plate, and is mainly used for a display device and a large TV, which are relatively small, such as a laptop computer and a desktop computer.

The display device having such a configuration reduces the thickness of the light guide plate in order to produce a lighter and thinner display device. Therefore, the area of the light incident portion through which the light of the light source reaches is reduced to reduce the light efficiency, and thus, the amount of light supplied to the display panel is reduced, resulting in a decrease in luminance.

One embodiment of the present invention is to provide a light guide plate and a method for manufacturing the same, which are intended to reduce the weight of the liquid crystal display module while improving the light receiving efficiency and are easy to manufacture.

According to one aspect of the invention, the light guide plate for the surface light source of the point light source or the line light source, formed on at least one side of both sides of the light guide plate, the light incident portion to which the light generated from the light source is incident; And a light exit part that changes the incident light into a surface light source and emits the light, wherein the light incident part surrounds the light source and spreads upward and downward to cover the light source, and the area of the light incident part is greater than the thickness direction cross-sectional area of the light exit part. A large light guide plate is provided.

According to one feature of the invention, the light incident portion may include a concave surface toward the light source.

According to another feature of the invention, the light incident portion, the first light incident portion is formed on the first side of the light guide plate and the light incident from the first light source; And a second light incident portion formed on a second side surface provided in parallel with the first side surface, and having light incident from a second light source. The light emitting portion is perpendicular to the first light incident portion and the second light incident portion. It may be provided to be.

According to another feature of the invention, the thickness of the light incident portion may be formed thicker than the thickness of the light exit portion.

According to another feature of the present invention, the light incident portion may include a surface having a centerline average roughness Ra of 0.5 μm or less.

According to still another aspect of the present invention, there is provided a method of manufacturing a light guide plate in which a point light source or a line light source is surface light source, comprising: preparing a transparent panel; And forming light incident portions provided on at least one side of both sides of the transparent panel, the light incident portions having upper and lower portions so as to surround a light source for generating light.

According to one feature of the invention, the preparing of the transparent panel, it is possible to prepare a transparent panel of a uniform thickness.

According to another feature of the present invention, the forming of the light incident part may form the light incident part by applying heat and force to a side surface of the transparent panel.

According to another feature of the invention, the force applied to the transparent panel may be made by using a pressing unit having a convex surface toward the side of the transparent panel.

According to another feature of the invention, the convex surface of the pressing portion may include a surface of the center line average roughness (Ra) is 0.5μm or less.

According to another feature of the invention, the convex surface of the pressing portion is a curved surface, the diameter of the convex surface may be formed larger than the thickness of the transparent panel.

According to another feature of the invention, the heat applied to the side of the transparent panel may be in the range of 20 ℃ ~ 150 ℃.

According to another feature of the invention, the force applied to the side of the transparent panel may be in the range of 100kgf ~ 2000kgf.

According to another feature of the invention, the step of forming the light incident portion, the step of fixing the transparent panel; Disposing a pressing portion having a surface convex toward the side of the transparent panel on the side of the transparent panel; And applying a force to a side surface of the transparent panel using the pressing unit while applying heat to at least one of the transparent panel and the pressing unit.

According to the exemplary embodiment of the present invention as described above, the light incident portion may be formed to have a relatively large area, thereby increasing light receiving efficiency and providing high luminance to the display panel.

In addition, according to an embodiment of the present invention, since the light guide plate may be produced through a simple process, manufacturing cost and time may be greatly reduced.

1 is a perspective view schematically showing a light guide plate according to an embodiment of the present invention.
2 is a cross-sectional view taken along the line II-II in Fig.
3 is a perspective view schematically showing a light guide plate according to another embodiment of the present invention.
4 is a cross-sectional view taken along line IV-IV of FIG. 3.
FIG. 5 is a cross-sectional view schematically illustrating a backlight unit in which the light guide plate of FIG. 3 is used.
6 is a flowchart schematically illustrating a method of manufacturing a light guide plate according to another embodiment of the present invention.
FIG. 7 is a perspective view schematically showing an embodiment of the transparent panel preparation step (S610) of FIG. 6.
FIG. 8 is a perspective view schematically showing an embodiment of the transparent panel fixing step S620 of FIG. 6.
FIG. 9 is a perspective view schematically showing an implementation state according to the pressing unit arranging step S630 of FIG. 6.
FIG. 10 is a perspective view schematically showing an embodiment according to the pressing step S640 of FIG. 6.
FIG. 11 is a perspective view schematically illustrating a light guide plate manufactured according to the flow of FIG. 6.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions. The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another.

1 is a perspective view schematically showing a light guide plate 100 according to an embodiment of the present invention, Figure 2 is a cross-sectional view taken along the line II-II of FIG.

Referring to the drawings, the light guide plate 100 is a member for changing the light generated from a point light source or a line light source to a surface light source, and includes a light incident part 110 and a light exit unit 130 for emitting light. do. The light incident part 110 is formed on one side of the light guide plate 100, and the light exit part 130 is formed on an upper surface perpendicular to the light incident part 110.

The light incident part 110 has a shape in which an upper portion and a lower portion thereof are opened. Due to the shape of the upper and lower portions of the light incident portion 110, the thickness t1 of the light incident portion 110 is thicker than the thickness t2 of the portion where the light exit portion 130 is formed in the light guide plate 100, and the light is incident. The area A1 of the light incident part 110 is relatively larger than the thickness direction cross-sectional area A2 of the light exit part 130. The light guide plate 100 is formed to have a thin thickness according to the weight reduction and peeling of the backlight unit. When light enters the light guide plate 100, the light guide plate 100 does not enter the light guide plate 100, and thus the amount of light leaks increases. The amount of light emitted from 100) decreases and the luminance decreases. However, according to the exemplary embodiment of the present invention, since the light incident part 110 forms a large area as the upper and lower portions are opened, the light leaked is greatly reduced.

The light incident part 110 includes a concave surface. Since the concave surface faces the light source 10, the light source 10 may be located in a space formed by the concave surface. That is, when the light source 10 is disposed adjacent to the concave surface, the light leaking as the upper and lower portions of the light incident part 110 surrounds the light source 10 is minimized. In this case, the light incident part 110 may cover part or all of the light source 10.

The concave surface of the light incident part 110 may be formed in a curved surface. In this case, the curvature of the concave surface may be formed to be substantially the same as the curvature of the light source 10. By forming the concave surface as a curved surface, it is possible to prevent the light generated from the light source 10 from being incident only to a specific portion and incident or only entering a specific path. On the other hand, the concave surface of the light incident portion 110 may be vertically symmetrical about the axis (X) passing through the most concave portion. Alternatively, it may be asymmetric along the vertical direction about the axis (X).

The light incident part 110 is a light incident part 110 having a smooth surface having a center line average roughness Ra of 0.5 μm or less, and may improve light efficiency. A process of forming the light incident part 110 will be described later in the corresponding part with reference to FIGS. 6 and 9.

The light exit unit 130 emits light incident through the light incident unit 110 to a surface light source and emits the light to the outside. The direction of the light emitted from the light exit unit 130 is a direction substantially perpendicular to the exit surface, and the light intensity is uniformly distributed throughout.

As described above, since the light incident part 110 has a large area and is formed relatively thick, the thickness t2 of the portion where the light exit part 130 is formed is thin, so that the weight and thickness can be reduced.

On the other hand, in order to improve the brightness and uniformity of the light emitted from the light emitter 130, a pattern (not shown) that can scatter light may be formed on the upper surface of the light guide plate 100, the inner surface is totally reflected A pattern (not shown) capable of condensing light may be formed.

In the present embodiment, the light source 10 is a case of a linear light source such as a light emitting lamp, but the present invention is not limited thereto. For example, an LED may be provided as a point light source, and in this case, the plurality of LEDs may be disposed at predetermined intervals.

3 is a perspective view schematically illustrating a light guide plate 300 according to another embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3.

Referring to the drawings, the light guide plate 300 according to the present exemplary embodiment also includes light receiving parts 310 and 320 and a light emitting part 330, and the light receiving parts 310 and 320 include a concave surface. The upper and lower portions of the 320 are opened to surround the light sources 10 and 20, and thus, the thickness t1 of the light incident portions 310 and 320 is thicker than the thickness t2 of the light exit portion 330. And the same as the light guide plate 100 described with reference to FIG. 2. However, the light guide plate 300 according to the present invention has a difference in that two light receiving parts 310 and 320 are provided. In the following description, for the convenience of explanation, the difference will be described.

The first light incident part 310 and the second light incident part 320 may be disposed in parallel to each other, and may be formed to have the same curvature and have the same area and thickness t1. The light incident through the first light incident part 310 and the light incident from the second light incident part 320 proceed according to the total reflection conditions inside the light guide plate 300, and then the scattering pattern formed on the light guide plate 300 (not shown). The total reflection condition is broken by the light exiting through the light emitter 330 to provide a surface light source to the display panel.

5 is a cross-sectional view schematically illustrating the backlight unit 500 as an embodiment in which the light guide part 300 of FIG. 3 is used.

Referring to FIG. 5, the backlight unit 500 may include a light source 10, 20, a light guide plate 300, a housing 510 for accommodating the light sources 10, 20, an optical sheet 520, a reflector 530, and the like. Include.

The housing 510 fixes the light sources 10 and 20 and condenses the light generated by the light sources 10 and 20 to the light incident part 310 of the light guide plate 300. In addition, since the light receiving plate 310 is formed in the light guide plate 300 to be widened to the top and bottom, the light receiving efficiency is increased.

The optical sheet 520 is disposed on the upper surface of the light guide plate 300 to increase the luminance of light emitted through the light exit portion 330 of the light guide plate 300.

The reflecting plate 530 is disposed on the lower surface of the light guide plate 300 to reflect the light leaking outward toward the upper surface, thereby increasing the brightness of the light guide plate 300.

6 is a flowchart schematically illustrating a method of manufacturing a light guide plate according to an embodiment of the present invention, and FIGS. 7 to 11 are perspective views illustrating a state according to a manufacturing step.

In operation S610, the transparent panel 700 is prepared. Referring to FIG. 7, the transparent panel 700 may have a substantially rectangular rectangular shape. The thickness t of the transparent panel 700 is constant. For example, as the transparent panel 700, a material of polymethyl methacrylate (PMMA), PC-based, and glass-based materials having excellent light transmittance may be used.

In operation S620, the transparent panel 700 is fixed. Referring to FIG. 8, the transparent panel 700 may be fixed using the jig 800. In FIG. 8, the jig 800 is disposed on both sides of the transparent panel 700, but the number and arrangement of the jig 800 are not limited thereto.

In operation S630, the pressing units 910 and 920 are disposed on the side surfaces of the transparent panel 700. Referring to FIG. 9, in the present exemplary embodiment, light guide plates having light incidence parts are formed on both sides, and the first pressing part 910 and the second pressing part 920 are respectively formed on both sides of the transparent panel 700. It shows the case where it was arranged.

The first and second pressing parts 910 and 920 have convex surfaces formed on the transparent panel 700 side. The convex surfaces of the first and second pressing parts 910 and 920 have the same shape and curvature as the concave surfaces of the light incidence parts 110, 310, and 320 described above with reference to FIGS. 1 to 4. That is, the surfaces of the light receiving parts 110, 310, and 320 are determined by the convex surfaces of the first and second pressing parts 910 and 920. Meanwhile, the diameter 2R of the convex surfaces of the first and second pressing parts 910 and 920 is larger than the thickness t of the transparent panel 700. In operation S640, the side surfaces of the transparent panel 700 are pressed using the pressing units 910 and 920. In this case, a force is applied to the side surface of the transparent panel 700 while applying a predetermined heat to the transparent panel 700. Alternatively, a force may be applied to the side surface of the transparent panel 700 while applying heat to the transparent panel 700 or the pressing parts 910 and 920 or after applying heat. As another example, the heat may be applied to the side surfaces of the pressing parts 910 and 920 and the transparent panel 700 simultaneously or after the heat is applied to the side surfaces of the transparent panel 700. By the heat, the transparent panel 700 is in a state where deformation of the shape is easy.

The temperature range of the applied heat may be set differently according to the type of the transparent panel 700. In the case of the transparent panel 700 which is a material of the PMMA, the temperature range may be about 20 ° C to 150 ° C. When the temperature is less than 20 ° C., the fluidity of the transparent panel 700 is poor, and molding of the light incident parts 1110 and 1120 by the pressing parts 910 and 920 to be described below becomes difficult, and the temperature exceeds 150 ° C. Due to the excessive fluidity of the transparent panel 700, it is difficult to obtain a desired shape such as the shape of the light incident parts 1110 and 1120 flowing down or distorting.

In this state, when a force is applied to the side surface of the transparent panel 700 by using the first pressing unit 910 and the second pressing unit 920, the transparent panel 700 is in a state of being easily deformed by heat and thus transparent. Sides of the panel 700 are changed in shape along the convex surfaces of the first and second pressing parts 910 and 920. In this case, the force applied to the transparent panel 700 may be set differently according to the strength of the transparent panel 700, and in the case of the transparent panel 700 which is a material of PMMA, the range of force may be about 100 kgf to 2000 kgf. have. If the force is less than 100 kgf, it is difficult to obtain the light receiving parts 1110 and 1120 having a desired shape. If the force is more than 2000 kgf, the light guide plate is bent or crushed as a whole.

Referring to FIGS. 10 and 11, after pressing the side surfaces of the transparent panel 700 by using the first and second pressing units 910 and 920, the first and second pressing units 910 and 920 are removed. The light guide plate 1100 having the light incidence portions 1110 and 1120 formed thereon is completed.

In steps S610 to S640, both sides of the uniform thickness of the transparent panel 700 are formed by using the pressing portions 910 and 920 having convex surfaces having a diameter 2R larger than the thickness t of the transparent panel 700. Since it pressed, the light-receiving parts 1110 and 1120 have a shape where the upper and lower portions thereof are opened.

The convex surfaces of the first and second pressing parts 910 and 920 may be mirror polished. For example, the convex surfaces of the first and second pressing parts 910 and 920 may include surfaces having a center line average roughness Ra of 0.5 μm or less. Therefore, the light incident parts 1110 and 1120 formed by the first and second pressing parts 910 and 920 also have smooth surfaces, thereby improving light efficiency.

In the above, the case of manufacturing the light guide plate 1100 having the light incidence parts 1110 and 1120 formed on both sides has been described. However, in operation S630 of disposing the pressing units 910 and 920, the first pressing unit 910 is formed only on one side of the transparent panel 700, and the first pressing unit 920 is disposed at a position where the second pressing unit 920 is disposed. A fixing part (not shown) may be further included to fix the transparent panel 700 so that the transparent panel 700 is not pushed back by the pressing operation of the pressing part 910.

When the thickness of the light guide plate becomes thin, the light leaking without entering the light guide plate may increase, and as a result, the brightness of the light emitted from the light guide plate may be greatly reduced. Since the light guide plates 100, 300, and 1100 having the light incidence parts 110, 310, 320, 1110, and 1120 are provided, the light incidence efficiency may be increased.

In addition, the light guide plate 1100 is provided through a simple process of applying heat and force to the pressing portions 910 and 920 having convex surfaces having a diameter 2R larger than the thickness t of the transparent panel 700 and the side surfaces of the transparent panel 700. ) Can be produced, which saves time and money.

In the light guide plates 100, 300, and 1100 according to the embodiments of the present invention, light is incident through the light incidence parts 110, 310, 320, 1110, and 1120, thereby increasing light efficiency and uniformity of light emitted. The light guide plates 100, 300, and 1100 may be used in various ways, ranging from small display devices to large display devices.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. Accordingly, it is intended that the appended claims cover all such modifications and variations as fall within the true spirit of the invention.

10, 20: light source 100, 300, 1100: light guide plate
110: light incident part 130, 330, 1130: light exit part
310, 1110: first light incident part 320, 1120: second light incident part
500: backlight unit 510: housing
520: optical sheet 530: reflector
700: transparent panel 800: jig
910: first pressure unit 920: second pressure unit
A1: area of the light incident portion A2: thickness direction cross-sectional area of the light guide plate
t1: thickness of the light incident portion t, t2: thickness of the light guide plate
X: axis

Claims (14)

A light guide plate for converting a point light source or line light source into a surface light source,
A light incident part formed on at least one side of both side surfaces of the light guide plate to which light generated from a light source is incident; And
And a light exit unit configured to change the incident light into a surface light source and emit the light.
The light guide plate is formed in the shape of the light incident portion is formed in the upper and lower portions surrounding the light source is larger than the thickness direction cross-sectional area of the light exit portion. The method of claim 1,
The light guide plate comprises a surface concave toward the light source. The method according to claim 1 or 2,
The light incident portion,
A first light incident part formed on a first side of the light guide plate and receiving light from a first light source; And
And a second light incident portion formed on a second side surface provided in parallel with the first side surface and having light incident from a second light source.
The light guide plate is provided to be perpendicular to the first light incident portion and the second light incident portion. The method of claim 1,
The light guide plate has a thickness greater than that of the light exit portion. The method of claim 1,
The light guide plate includes a surface having a center line average roughness Ra of 0.5 μm or less. In the manufacturing method of the light guide plate which makes a point light source or a line light source into a surface light source,
Preparing a transparent panel; And
And a light receiving part provided on at least one side of both sides of the transparent panel, the light receiving part having a shape spreading upwardly and downwardly to surround a light source generating light. The method of claim 6,
The preparing of the transparent panel may include preparing a light guide plate having a uniform thickness. The method of claim 6,
Forming the light incident portion,
The light guide plate manufacturing method of forming a light incident portion by applying heat and force to the side of the transparent panel. The method of claim 8,
The force applied to the transparent panel is a manufacturing method of the light guide plate using a pressing portion having a convex surface toward the side of the transparent panel. 10. The method of claim 9,
The convex surface of the pressing portion is a curved surface, the diameter of the convex surface is formed larger than the thickness of the transparent panel manufacturing method of the light guide plate. 10. The method of claim 9,
The convex surface of the pressing unit includes a surface having a center line average roughness Ra of 0.5 μm or less. The method of claim 8,
Heat applied to the side of the transparent panel is a method of manufacturing a light guide plate in the range of 20 ℃ ~ 150 ℃. The method of claim 8,
The force applied to the side of the transparent panel is a method of manufacturing a light guide plate in the range of 100kgf ~ 2000kgf. The method of claim 6,
Forming the light incident portion,
Fixing the transparent panel;
Disposing a pressing portion having a surface convex toward the side of the transparent panel on the side of the transparent panel; And
And applying a force to a side surface of the transparent panel using the pressing part while applying heat to at least one of the transparent panel and the pressing part.

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