KR20200134770A - Light guide plate having complex pattern - Google Patents

Abstract

According to the present invention, since the disclosed light guide plate having a complex pattern relates to a light plate of an edge type backlight unit included in a liquid crystal display device, in the light guide plate, a plurality of engraved line patterns are formed on a lower surface in a direction perpendicular to a light incident surface, and a plurality of engraved dot patterns are formed on the lower surface in a direction parallel to the light incident surface, wherein the lower surface of the light guide plate is formed with the complex pattern which is spaced apart from reflective sheets which are disposed to face each other by a burr generated when forming intaglio patterns. According to the present invention, it is possible to improve a moire phenomenon and improve the amount and uniformity of light emitted.

Description

Light guide plate with composite pattern {LIGHT GUIDE PLATE HAVING COMPLEX PATTERN}

The present invention relates to a light guide plate on which a composite pattern is formed, and more particularly, to a light guide plate that transmits light emitted from an LED lamp of a backlight unit of a liquid crystal display device to the front surface of a backlight unit.

When the liquid crystal display (LCD) is largely divided, it can be divided into a liquid crystal panel and a backlight unit.

Technically, the liquid crystal panel functions by using light from the outside. The device that supplies such light is the backlight unit, and one of the very important parts in the backlight unit is the light guide plate (LGP: Light). Guide Plate).

The light guide plate induces diffuse reflection of light by applying a special treatment to the back side so that the entire light is projected evenly.

When patterning is performed in consideration of the distance from the light source located on the side of the backlight unit, the light guide plate that was bright at both ends close to the light source emits uniform light from the front side.

As a light source for LCD backlights, a light emitting diode (LED), which is advantageous for thinner and low power consumption, is widely used.

On the upper part of the light guide plate, optical sheets that control the optical path so that the light emitted through the light guide plate is input to the liquid crystal panel without loss are combined and mounted.

In general, optical PMMA (Poly Methyl Meth Acrylate), which is a plastic with the best light transmittance and weather resistance, is used as a raw material for the light guide plate.

PMMA is an acrylic resin that uses MMA Monomer as the main raw material, and is produced by copolymerizing MMA and MA or MMA and EA.

PMMA has the best permeability (93%) among resins, excellent weather resistance, excellent colorability, and beautiful appearance. It is widely used in various fields such as interior and exterior materials for automobiles and buildings in addition to light guide plates. Some PC materials are also used.

The light guide plate essentially needs a structure for uniformly distributing the incoming light, which is its original function, over a certain area.

Often referred to as an optical pattern in the industry, the pattern is broadly classified into a printed type light guide plate and a non-print type light guide plate according to the process of disposing the pattern on the light guide plate.

The initial manufacturing method of the light guide plate was called a printed light guide plate by using a method of additionally printing an optical pattern after making a structure without an optical pattern according to a predetermined size, and it has evolved into a non-print type light guide plate made at once without additional printing process. .

Generally, as a method to improve the luminance characteristics of the light guide plate, a method of forming a circular reflective dot on the lower surface of the light guide plate using silk screen printing technology or laser processing is mainly used. In addition to emitting light, there is a problem in that the light efficiency in the optical pattern decreases due to different materials of the reflective dot and the light guide plate when the silk screen printing technique is used.

An object of the present invention is to provide a light guide plate in which a composite pattern is formed in which various patterns are applied to one light guide plate.

In addition, an object of the present invention is to provide a light guide plate having a composite pattern with improved moiré phenomenon.

In addition, an object of the present invention is to provide a light guide plate having a composite pattern in which the amount of light emitted is increased.

In addition, an object of the present invention is to provide a light guide plate having a composite pattern with improved uniformity of emitted light.

The above object is to provide a light guide plate of an edge type backlight unit included in a liquid crystal display, wherein the light guide plate has a plurality of intaglio patterns formed on the lower surface in a direction perpendicular to the light incident surface, and the light guide plate is formed in a direction parallel to the light incident surface. The intaglio dot pattern of is formed on the lower surface, and the lower surface of the light guide plate can be achieved by the light guide plate on which the composite pattern is formed to be spaced apart from the reflective sheet disposed facing each other by a burr generated when forming the intaglio line pattern. .

In addition, the above object can be achieved by the light guide plate on which the concave line pattern is formed with a V-cut pattern or a U-cut pattern.

In addition, the above object can be achieved by a light guide plate in which a composite pattern is formed in which the interval of the intaglio dot pattern is uniformly narrowed along the Bezier curve toward the center of the lower surface with respect to the direction perpendicular to the light incident surface.

In addition, the above object can be achieved by a light guide plate having a composite pattern in which the size of the concave dot pattern increases toward the center of the lower surface with respect to the direction perpendicular to the light incident surface, along the Bezier curve.

In addition, the above object can be achieved by a light guide plate on which a composite pattern in which a plurality of embossed line patterns are formed is formed on an upper surface of the light guide plate.

In addition, the above object can be achieved by a light guide plate on which a plurality of embossed line patterns formed on the upper surface of the light guide plate are formed with a complex pattern having any one of a triangular, square, or dome shape.

In addition, the above object can be achieved by a light guide plate on which a lenticular lens pattern or a composite pattern in which a sawtooth pattern is formed is formed on the light incident surface of the light guide plate.

Further, the above object can be achieved by a light guide plate in which a composite pattern is formed on the upper surface of the light guide plate to coat a diffusion film in place of the diffusion sheet.

According to the present invention, the light guide plate on which the composite pattern is formed is a light guide plate of an edge type backlight unit included in a liquid crystal display, wherein the light guide plate has a plurality of intaglio patterns formed on the lower surface in a direction perpendicular to the light incident surface, and the light guide plate is A plurality of engraved dot patterns are formed on the lower surface in a direction parallel to the light surface, and the lower surface of the light guide plate is spaced apart from the reflective sheet arranged facing each other by a burr generated when forming the engraved line pattern. And improves the amount and uniformity of the emitted light.

In addition, according to the present invention, the light guide plate on which the composite pattern is formed can improve the moire phenomenon by a burr generated when the intaglio line pattern is formed as a V cut pattern or a U cut pattern.

In addition, according to the present invention, in the light guide plate on which the composite pattern is formed, since the interval of the intaglio dot pattern is uniformly narrowed along the Bezier curve toward the center of the lower surface with respect to the direction perpendicular to the light incident surface, the amount of emitted light and Uniformity can be improved.

In addition, according to the present invention, in the light guide plate on which the composite pattern is formed, the size of the concave dot pattern increases consistently along the Bezier curve toward the center of the lower surface with respect to the direction perpendicular to the light incident surface. Uniformity can be improved.

In addition, according to the present invention, since a plurality of embossed line patterns may be formed on the upper surface of the light guide plate on which the composite pattern is formed, the amount and uniformity of light emitted can be improved.

In addition, according to the present invention, since the cross section of the plurality of embossed lines formed on the upper surface of the light guide plate on which the composite pattern is formed may be any one of a triangle, a square, or a dome, the amount of light and uniformity of the emitted light can be improved.

In addition, according to the present invention, since the light guide plate on which the composite pattern is formed may have a lenticular lens pattern or a sawtooth pattern formed on the light incident surface, the amount and uniformity of light emitted can be improved.

Further, according to the present invention, since the light guide plate on which the composite pattern is formed can be coated with a diffusion film instead of the diffusion sheet on the upper surface of the light guide plate, the structure of the backlight unit can be simplified.

1 is a front view schematically showing a backlight unit including a light guide plate on which a composite pattern is formed according to a first embodiment of the present invention.
2 is a perspective view schematically showing a light guide plate on which a composite pattern is formed according to Embodiment 1 of the present invention.
3 is a side view schematically showing a light guide plate on which a composite pattern is formed according to Embodiment 1 of the present invention.
4 is a bottom view schematically showing a light guide plate on which a composite pattern is formed according to Embodiment 1 of the present invention.
5 is a perspective view schematically showing a light guide plate having an embossed line pattern formed on an upper surface according to Embodiment 2 of the present invention.
6 is a perspective view schematically showing a light guide plate having a lenticular lens pattern formed on a light incident surface according to a third embodiment of the present invention.
7 is a perspective view schematically showing a light guide plate having a sawtooth pattern formed on a light incident surface according to a third embodiment of the present invention.
8 is a perspective view schematically showing a light guide plate coated with a diffusion film according to a fourth embodiment of the present invention.

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

However, in describing the present invention, a description of a function or configuration that is already known will be omitted in order to clarify the gist of the present invention.

The X, Y, and Z axes shown in the drawings are arbitrarily determined for convenience of explanation, not for the purpose of limitation of rights, and the X axis indicates the front (arrow side) and the rear (opposite side of the arrow) direction, and the Y axis is left and right direction. And the Z axis is defined as indicating the up and down directions.

Each direction to be described below is based on this, except for a case otherwise specifically limited.

In the description and claims of the invention, the upper (upper), lower (lower), left and right (lateral or lateral), front (front, front), rear (fold, rear), etc., which refer to directions, etc. For convenience of description, it is determined based on the relative position between the drawings and the components, and each direction described below is based on this, except for cases specifically limited differently.

1 to 2, in the light guide plate 100 on which the composite pattern is formed according to the first embodiment of the present invention, in the light guide plate 100 of the edge type backlight unit 10 included in the liquid crystal display device, the light guide plate ( 100) has a plurality of intaglio patterns 122 formed on the lower surface 120 in a direction perpendicular to the light incident surface 140, and the light guide plate 100 is a plurality of intaglios in a direction parallel to the light incident surface 140 The dot pattern 125 is formed on the lower surface 120, and the lower surface 120 of the light guide plate 100 is a reflection arranged facing each other by the burr 123 generated when the intaglio pattern 122 is formed. It is spaced apart from the sheet 200.

The edge type backlight unit 10 is applied to a large-sized ultra-thin LCD TV in a form in which the LED lamp 500 is positioned on the side of the plate-shaped light guide plate 100.

The edge type backlight unit 10 has a structure in which a reflective sheet 200 is located below the light guide plate 100, a diffusion sheet 300 is located above, and a prism sheet 400 is located above the diffusion sheet 300 to be.

The reflective sheet 200 is a sheet that reduces the loss of light emitted from the LED lamp 500, and is positioned on the lower surface of the light guide plate 100 to reflect the light that exits without reflecting the inside of the light guide plate 100.

That is, the reflective sheet 200 serves to reflect light exiting the lower surface 120 of the light guide plate 100 again and return it into the light guide plate 100.

The diffusion sheet 300 is a sheet that scatters light exiting the upper surface 160 of the light guide plate 100 again to spread light evenly, and provides soft light by dividing the light from the light guide plate 100 and distributing it evenly. do.

The prism sheet 400 is a sheet that increases light efficiency released from the initial LED lamp 500, and increases luminance by refracting and condensing light emitted from the diffusion sheet 300.

The light guide plate 100 is a plastic sheet that allows light entering the side of the light-incident surface 140 to go out to the upper surface 160, and the light generated by the LED lamp 500 enters the light-incident surface 140 of the light guide plate 100. Next, the intaglio line pattern 122 and the intaglio dot pattern 125 formed on the lower surface 120 of the light guide plate 100 go out to the upper surface 160 of the light guide plate 100.

Light entering the light guide plate 100 does not come out to the upper surface 160 of the light guide plate 100 due to total reflection, but the intaglio line pattern 122 and the intaglio dot pattern 125 make total reflection as diffuse reflection, and the light guide plate 100 It allows the light that has entered the inside to exit to the upper surface 160.

The concave line pattern 122 and the concave dot pattern 125 make a line light source a surface light source.

The intaglio pattern 122 is preferably a V cut pattern 124 formed on the lower surface 120 of the light guide plate 100 using a diamond blade, and a U cut pattern is also possible.

When the intaglio pattern 122 is formed, a burr 123 protruding downward is formed at the boundary between the intaglio pattern 122 and the lower surface 120 of the light guide plate 100.

Since the burr 123 separates the lower surface 120 of the light guide plate 100 and the reflective sheet 200, a moire phenomenon occurs when the lower surface 120 of the light guide plate 100 and the reflective sheet 200 come into contact with each other. Can be improved.

The intaglio pattern 122 is formed on the lower surface 120 of the light guide plate 100 in a direction perpendicular to the light incident surface 140 in order to minimize scattering of light.

When the intaglio pattern 122 is formed parallel to the light incident surface 140 of the light guide plate 100, the diffuse reflection area is widened, and thus the amount of scattered light increases.

In order to illuminate a screen with a large area, it is preferable that the intaglio pattern 122 is formed in a direction perpendicular to the light incident surface 140 than that in a horizontal direction.

Table 1 below shows when the V-cut pattern 124 is formed on the lower surface 120 of the light guide plate 100, when the intaglio dot pattern 125 is formed, the V-cut pattern 124 and the intaglio dot pattern 125 are together. When formed, the quality is compared.

As can be seen from Table 1, when the V-cut pattern 124 and the intaglio dot pattern 125 are formed together on the lower surface 120 of the light guide plate 100, they are emitted from the inside of the light guide plate 100 to the upper surface 160 The amount of light and uniformity of the resulting light are good, and no moire phenomenon occurs.

Formation of V cut pattern alone Formation of intaglio dot pattern alone V cut pattern and intaglio dot pattern
Formed together

Decreased light intensity and uniformity of light Moire phenomenon occurs Good intensity and uniformity of light
No moiré phenomenon

3 to 4, the concave dot pattern 125 is a groove formed in a direction parallel to the light incident surface 140 of the light guide plate 100, and has a triangular, square, or dome shape in cross section.

The intaglio dot pattern 125 is for improving the light quantity and uniformity of the emitted light, and may be formed at least one between the intaglio line patterns 122.

It is preferable that the intaglio dot pattern 125 has a size of 30 μm to 1000 μm.

The spacing of the intaglio dot patterns 125 may be uniformly narrowed along a Bezier curve toward the center of the lower surface 120 based on a direction perpendicular to the light incident surface 140.

The density of the intaglio dot pattern 125 may be increased consistently along the Bezier curve toward the center of the lower surface 120 based on a direction perpendicular to the light incident surface 140.

The size of the intaglio dot pattern 125 may be made to be increased consistently along the Bezier curve toward the center of the lower surface 120 based on a direction perpendicular to the light incident surface 140.

Since the amount of light decreases as the distance from the LED lamp 500 increases, the distance, density, or size of the intaglio dot pattern 125 toward the center of the lower surface 120 based on the direction perpendicular to the light incident surface 140 Can be adjusted to cause more light scattering.

The spacing, density, or size of the intaglio dot patterns 125 located along the Bezier curve can be adjusted individually or together, and the intaglio dot pattern 125 adjusted along the Bezier curve is the light guide plate 100 Light that is totally reflected within and exits the upper surface 160 can be uniformly scattered.

The Bezier curve is an n-1 order curve obtained from n points, and is a method of adjusting the spacing by specifying the number and center position of the intaglio dot patterns 125.

The spacing of the intaglio dot patterns 125 may be set to be uniformly narrowed according to the Bezier curve.

For example, for the start point A, the control point B, and the end point C, the quadratic Bezier curve is a trace of the point P(t) defined by Equation 1 below.

Here, assuming that the start point A and the end point C are points located on the Y-axis on the upper surface 160 of the light guide plate 100, the start points A and the end points C are points positioned at the left and right ends of the light guide plate 100, and the control point B is This is a point that is spaced upward from the upper surface 160 of the light guide plate 100 and is positioned on the Z axis.

Embodiments 2 to 4 are modified embodiments of Embodiment 1, and the content of Embodiment 1 described above is the same, except for the content described in each embodiment below.

5, in the light guide plate 100 on which the composite pattern according to the second embodiment of the present invention is formed, a plurality of embossed line patterns 162 having a triangular, square, or dome shape may be formed on an upper surface 160. have.

The embossed line pattern 162 may be integrally formed on the light guide plate through an extrusion process or an injection process,

Light incident on the light-incident surface 140 of the light guide plate 100 proceeds through total reflection inside the light guide plate 100, and the light is emitted upwards of the light guide plate 100 by the embossed line pattern 162.

When the concave line pattern 122 and the concave dot pattern 125 are formed on the lower surface 120 of the light guide plate 100 and the embossed line pattern 162 is formed on the upper surface of the light guide plate 100, the amount of light according to the viewing angle Can improve.

The density of the embossed line pattern 162 may be uniformly increased along the Bezier curve toward the center of the upper surface based on a direction horizontal to the light incident surface 140.

The size of the embossed line pattern 162 may be uniformly increased along the Bezier curve toward the center of the upper surface based on a direction horizontal to the light incident surface 140.

The embossed line pattern 162 may be formed in a direction perpendicular to the light incident surface 140.

6 to 7, in the light guide plate 100 on which the composite pattern is formed according to the third embodiment of the present invention, a lenticular lens or a sawtooth-shaped fine pattern may be formed on the light incident surface 140.

The lenticular lens pattern 142 or the sawtooth pattern 144 formed on the light incident surface 140 may be formed through an injection process or laser processing, so that the light emitted from the LED lens spreads evenly into the light guide plate 100. do.

Since the lenticular lens pattern 142 or the sawtooth pattern 144 is locally concentrated due to the refraction of light and evenly spreads the light of the incident LED lens, the amount of light and the uniformity of the light emitted from the light guide plate 100 are improved. I can make it.

If the lenticular lens pattern 142 or the sawtooth pattern 144 is not formed on the light-incident surface 140, the amount and uniformity of light emitted from the light guide plate 100 is the distance between the LED lens and the light-incident surface 140 Is affected a lot.

However, when the lenticular lens pattern 142 or the sawtooth pattern 144 is formed on the light-incident surface 140, the amount and uniformity of light emitted from the light-guide plate 100 is determined by the distance between the LED lens and the light-incident surface 140. Less affected.

When the refractive index of the light guide plate 100 is increased, the angle at which the light is bent from the lenticular lens pattern 142 or the sawtooth pattern 144 increases, so that the light emitted from the LED lens spreads more evenly into the light guide plate 100. Can be done.

The sawtooth pattern 144 becomes closer to the case where the sawtooth pattern 144 is not present on the light-incident surface 140 of the light guide plate 100 as the intervening angle θ of the sawtooth increases, and the smaller the intervening angle θ, the light Since the refractive effect of is reduced and the light of the LED lens cannot be spread evenly, the intervening angle (θ) of the teeth is preferably 80 to 100°.

Referring to FIG. 8, the light guide plate 100 on which the composite pattern is formed according to the fourth embodiment of the present invention may be coated with a diffusion film 180 instead of the diffusion sheet 300 on the upper surface 160.

Like the diffusion sheet 300, the diffusion layer 180 is a coating layer that scatters light emitted to the upper surface 160 of the light guide plate 100 to spread the light evenly. Distributed to provide a soft light.

The diffusion layer 180 may be formed on the upper surface 160 of the light guide plate 100 on which the embossed line pattern 162 is not formed, and a diffusion layer pattern (not shown) is formed on the diffusion layer 180 Thus, the embossed line pattern 162 may be replaced.

The diffusion layer pattern may be formed in a lenticular lens or sawtooth shape, similar to the embossed pattern.

The diffusion layer 180 may be formed on the embossed line pattern 162.

In the above, although specific embodiments of the present invention have been described and illustrated, the present invention is not limited to the described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. It is self-evident to those who have.

Therefore, such modifications or variations should not be individually understood from the technical spirit or viewpoint of the present invention, and the modified embodiments should be said to belong to the claims of the present invention.

10: Backlight unit
100: light guide plate
120: lower side
122: negative line pattern
123: Burr
124: V cut pattern
125: negative dot pattern
140: light incident surface
142: lenticular lens pattern
144: sawtooth pattern
160: top surface
162: embossed line pattern
180: diffusion film
200: reflective sheet
300: diffusion sheet
400: prism sheet
500: LED lamp

Claims (8)

In the light guide plate of an edge type backlight unit included in a liquid crystal display device,
The light guide plate has a plurality of engraved line patterns formed on the lower surface in a direction perpendicular to the light incident surface,
The light guide plate has a plurality of engraved dot patterns formed on the lower surface in a direction parallel to the light incident surface,
The lower surface of the light guide plate is formed with a composite pattern that is spaced apart from a reflective sheet disposed to face each other by a burr generated when the intaglio pattern is formed. The method of claim 1,
The intaglio pattern is a V-cut pattern or a U-cut pattern. The method of claim 1,
The light guide plate on which the composite pattern is formed, wherein the interval between the intaglio dot patterns is uniformly narrowed along a Bezier curve toward the center of the lower surface based on a direction perpendicular to the light incident surface. The method of claim 1,
The size of the intaglio dot pattern increases as the center of the lower surface increases in a constant manner along a Bezier curve based on a direction perpendicular to the light incident surface. The method according to any one of claims 1 to 4,
The light guide plate having a composite pattern, characterized in that a plurality of embossed line patterns are formed on an upper surface of the light guide plate.
The method of claim 5,
The embossed line pattern is a light guide plate with a composite pattern, characterized in that any one of a triangular, square, or dome-shaped cross section. The method according to any one of claims 1 to 4,
The light guide plate has a composite pattern formed thereon, wherein a lenticular lens pattern or a sawtooth pattern is formed on a light incident surface. The method according to any one of claims 1 to 4,
The light guide plate having a composite pattern formed thereon, wherein the light guide plate is coated with a diffusion film instead of the diffusion sheet on an upper surface thereof.

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