KR100952736B1 - Light diffusion plate, and back light unit thereby, LCD device thereby - Google Patents

Abstract

Provided are a light diffusion plate having excellent light scattering property and light diffusing property and excellent heat deformation characteristics, a backlight unit including the same, and a liquid crystal display device including the same. The light diffusing plate according to the present invention is 0.1 to 10 parts by weight of a siloxane light diffusing agent having an average particle diameter of 1 to 20 μm with respect to 100 parts by weight of polypropylene resin, and 0.1 to 10 parts of acrylic light diffusing agent having an average particle diameter of 1 to 20 μm. A base layer having 10 parts by weight dispersed therein; And an embossed pattern formed on one surface or both surfaces of the substrate layer, bubbles formed therein, and on the surface of the substrate opposite to the surface laminated with the substrate layer, with respect to 100 parts by weight of polypropylene resin, 0.1-30 weight part, a ultraviolet absorber 0.01-2 weight part, and an antistatic agent 0.001-10 weight part.

Light Diffusion Plate, Polypropylene, Coating Layer, Bubble, Light Diffusion Agent

Description

A light diffusion plate, a backlight unit including the same, and a liquid crystal display including the same.

The present invention relates to a light diffusion plate, and more particularly, to a light diffusion plate containing a light diffusing agent and a bubble in a base resin, a backlight unit including the same, and a liquid crystal display device including the same.

The liquid crystal display includes a liquid crystal display panel including two substrates on which electrodes are formed and a liquid crystal layer interposed therebetween, and by rearranging the liquid crystal molecules of the liquid crystal layer by applying a voltage to the electrode. The display device controls the amount of light transmitted. A backlight unit for providing light is disposed below the liquid crystal display panel.

The backlight unit is classified into an edge type backlight unit in which lamps are disposed on the side of the bottom chassis and a direct type backlight unit in which a plurality of lamps are disposed on the bottom surface of the bottom chassis according to the position of a light source providing light. In the case of the direct type backlight unit, the light diffusion plate and the optical sheets are disposed directly on the plurality of lamps.

Recently, research on ultra-light backlights that have dramatically reduced the thickness and weight of the backlight unit has been conducted. In this case, the ultra-light slim backlight unit refers to a thin backlight unit, and for this purpose, the distance between the lamp and the optical member should be close.

As the distance increases, it is difficult to conceal a lamp image with a conventional diffuser plate, and the diffuser plate tends to be easily deformed or modified by heat or ultraviolet rays generated from the lamp.

The technical problem to be achieved by the present invention is to provide an excellent light diffusivity and excellent heat resistance in response to the enlargement of the LCD panel is possible to manufacture an ultra-lightweight slim backlight unit, while excellent in light resistance while less deformation due to heat and moisture absorption Therefore, the present invention provides a light diffusion plate for a backlight unit of a liquid crystal display device having a low manufacturing cost.

Another object of the present invention is to provide a backlight unit including the light diffusion plate as described above.

Another object of the present invention is to provide a liquid crystal display device including the backlight unit as described above.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

Light diffusing plate according to an embodiment of the present invention for solving the above problems 0.1 to 10 parts by weight, 1 ~ 1 of the siloxane light diffusing agent having an average particle diameter of 1 to 20㎛ with respect to 100 parts by weight of polypropylene resin A substrate layer in which 0.1 to 10 parts by weight of an acrylic light diffusing agent having an average particle diameter of 20 μm is dispersed; And an embossed pattern formed on one surface or both surfaces of the substrate layer, bubbles formed therein, and on the surface of the substrate opposite to the surface laminated with the substrate layer, with respect to 100 parts by weight of polypropylene resin, 0.01-2 weight part of ultraviolet absorbers and 0.001-10 weight part of antistatic agents.

The backlight unit according to an embodiment of the present invention for solving the other problem includes a light diffusion plate as described above.

The liquid crystal display according to the exemplary embodiment of the present invention for solving the another problem includes the backlight unit as described above.

Specific details of other embodiments are included in the detailed description and drawings.

In the light diffusion plate according to some embodiments of the present invention, a spherical siloxane light diffuser and an acrylic diffuser having excellent light diffusivity and light transmittance are applied to a base layer including a polypropylene resin at a lower price than an acrylic or styrene resin. In addition, by forming an embossed pattern on the surface of the micro-sized bubbles and the coating layer externally, excellent light scattering property, light diffusibility, and light transmittance are exhibited.

Furthermore, according to some embodiments of the present invention, the organic light diffusing agent may be used to reduce wear and tear of the light diffusing manufacturing equipment and to evenly disperse the light diffusing agent to prevent aggregation between the particles. In addition, by applying the organic light diffusing agent and micro-sized bubbles, embossing pattern, etc., the scattering property is increased, thereby reducing the amount of light diffusing agent used. In addition, since the antistatic agent and the light stabilizer can be selectively formed only on the surface layer, the manufacturing cost can be reduced.

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.

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

1 is a perspective view of a light diffusing plate according to an embodiment of the present invention.

Referring to FIG. 1, the light diffusion plate 20 according to an embodiment of the present invention includes a base layer 200 and an application layer 210 stacked on both sides of the base layer 200.

The base material layer 200 includes polypropylene resin as a base resin. The polypropylene resin may have a weight average molecular weight of about 100,000 or less.

The scattering degree (Haze) of the polypropylene resin may be about 50 or less based on the thickness 2mm.

The polypropylene resin is relatively cheaper than the transparent thermoplastic resin such as methacryl resin, styrene resin, cyclic olefin resin, polycarbonate resin, etc., and has excellent heat deformation characteristics.

Therefore, there is an advantage that the durability is improved. In addition, it is excellent in light resistance than the other resins listed above can reduce the amount of light stabilizers and the like used. Therefore, the problem of brightness deterioration due to the use of the light stabilizer can be improved.

The light diffusing agent is dispersed in the polypropylene resin. Preferably it may be evenly distributed throughout the volume of the polypropylene resin.

The light diffusing agent employed in some embodiments of the present invention includes at least one of a siloxane light diffusing agent and an acrylic light diffusing agent.

The siloxane light diffusing agent is a solid silicone resin particle at room temperature, and includes both a silicone rubber having a low crosslinking density and flexibility, and a silicone resin having a high crosslinking density and a hard silicone resin. Specific examples of the siloxane light diffusing agent include polydialkyl siloxane resins such as polydimethyl siloxane and polydiethyl siloxane, and silicone resins having a three-dimensional network structure such as siloxane having an epoxy in the terminal group.

Since the siloxane light diffusing agent has excellent weather resistance, yellowing does not occur in which the exposed part turns yellow even when the final resin composition is exposed to light for a long time.

In addition, since the siloxane-based light diffusing agent has a refractive index of about 1.40 to 1.43, which is lower than other light diffusing agents, even when only a small amount is added, light diffusion and light transmittance equivalent to those of other light diffusing agents can be obtained.

The siloxane light diffusing agent used in the present invention may be spherical crosslinked fine particles having an average diameter of about 1 to 20 μm. The content of the siloxane light diffusing agent may be about 0.1 to 10 parts by weight based on 100 parts by weight of the polypropylene resin.

Acrylic light diffusing agent may be used that has a refractive index of about 1.46 to 1.56 degree. Acrylic light diffusing agents are acrylic monofunctional monomers, for example, methacrylic acid esters such as ethyl methacrylate, methyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, And acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, and benzyl acrylate, and the like, and any one or two or more of them may be used as necessary.

Acrylic light diffusing agent can be used by adjusting the refractive index through copolymerization with methacryl-based alone or styrene. When the acrylic light diffusing agent has many phenyl or halogen groups, the refractive index of the particles is usually high.

The acrylic light diffusing agent used in the present invention may be spherical crosslinked fine particles having an average particle diameter of about 1 to 20 μm. The content of the acrylic light diffusing agent may be about 0.1 to 10 parts by weight based on 100 parts by weight of the polypropylene resin.

The substrate layer 200 of the light diffusion plate 20 according to some exemplary embodiments of the present invention may further include an impact modifier in addition to the polypropylene resin and the light diffusing agent.

The impact modifier may be mixed or copolymerized with the polypropylene resin or dispersed. Impact modifiers include, but are not limited to, rubber components such as acrylic rubber, butadiene rubber, and the like. When the rubber component is copolymerized with the polypropylene resin, since the rubber component has large impact resistance and bending elastic modulus, physical properties of the polypropylene resin may be improved.

The thickness of the base layer 200 may be, for example, about 100 to 10,000 μm, but is not limited thereto.

Referring back to FIG. 1, the coating layer 210 is formed by being stacked on both sides of the base layer 100.

The base resin of the coating layer 210 is a polypropylene resin as in the case of the base material layer 200. The molecular weight, scattering degree, characteristics, specific examples, etc. of the polypropylene resin that can be applied are the same as those described for the polypropylene resin of the base layer 100.

In the coating layer 210, bubbles are formed in the polypropylene resin in addition to the polypropylene resin, and an embossing pattern is formed on the surface of the surface opposite to the surface laminated with the base layer 200, and inside the coating layer 210. May further include a light diffusing agent.

Bubbles formed inside the coating layer 210 have a diameter of about 0.1 to 20㎛. Preferably, bubbles 215 may be evenly distributed throughout the polypropylene resin 210 of the coating layer 201.

As such, the micro-sized bubbles 215 formed inside the coating layer 201 exhibit excellent light scattering properties and light diffusing properties due to high refractive index differences. Therefore, not only the light scattering property and the light diffusivity of the entire light diffusing sheet 11 can be improved, but also the use of the light diffusing agents 120 and 220 in the base layer 100 and / or the coating layer 201 is reduced. In addition, it can be expected to further improve the light resistance accordingly.

The bubble 215 inside the coating layer 201 may be formed by foaming or the like. In a more specific example, gas is added to and dispersed in a polypropylene resin. Subsequently, the degassing process which exits out of the die in the mixed state in the supercritical state is performed to form bubbles 215 in the polypropylene resin.

Gases used to generate the micro-sized bubbles 215 include nitrogen, carbon dioxide, butane, pentane, air, hydrogen, helium, ammonia gas, and the like. Preferably, nitrogen and carbon dioxide can be used.

The addition amount of the gas may be about 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 1 part by weight or less based on 100 parts by weight of the polypropylene resin of the coating layer. The gas can be sufficiently dissolved in the polypropylene resin within the above range.

Therefore, appearance defects, such as a die-line produced | generated by remaining on the sheet surface, can be prevented. In addition, the addition amount of the gas facilitates the manufacture of bubbles 215 of uniform size.

On the other hand, unlike the present embodiment, bubbles may be formed in the base layer 200, not the coating layer 210, or may be formed in both the coating layer 201 and the base layer 100.

The embossing pattern is not formed on the outer surface of the coating layer 210, that is, the surface on which the base layer 200 and the coating layer 210 contact, but is formed in an uneven pattern having convex and concave surfaces on opposite surfaces thereof.

The embossing pattern uniformly scatters the light incident from the lamp, and serves to make the bright lines of the lamp invisible.

That is, light directly incident from the lamp (for example, when the lamp is disposed below the light diffusion plate and the coating layer is formed on the bottom surface of the substrate layer) or diffused by the light diffuser 120 of the substrate layer 100. Light transmittance and light diffusivity can be achieved by scattering and diffusing light (for example, when a lamp is disposed below the light diffusing plate and an application layer is formed on the upper surface of the substrate layer) in various directions instead of a constant direction through an embossing pattern. Increase the overall average brightness.

In view of the above, the embossing pattern on the surface of the coating layer 210 may be an amorphous pattern having an average roughness of about 0.1 to 10 μm. However, the specific shape, roughness, and the like of the embossing pattern 230 may be flexibly modified according to the distance between the light diffusion plate 12 and the lamp, the brightness of the lamp, the number of lamps, and the arrangement of the lamps.

The embossing pattern may be formed by press working, UV resin coating after processing, contact processing by a polishing roll having an uneven pattern, or the like. In consideration of the mass productivity of the light diffusion plate, processing by a polishing roll can be selected.

The light diffusing agent dispersed in the coating layer 210 includes an acrylic light diffusing agent. Applicable acrylic light diffusing agent is as mentioned while explaining the base layer, but the acrylic light diffusing agent used in the coating layer 200 may be selected in various ranges from 1 to 50㎛ average particle diameter.

The coating layer 210 may further include a siloxane light diffuser having a diameter of 1 to 20 μm in addition to the acrylic light diffuser.

The coating layer 210 according to some embodiments of the present invention may further include a light stabilizer, an antistatic agent, an ultraviolet absorber, etc. in addition to the polypropylene resin and the light diffusing agent.

The light stabilizer has a function of capturing free radicals to further improve the durability of the resin composition. Hindered amines can be used. Typically can be used in parallel with ultraviolet absorbers. As described above, when the polypropylene resin is used as the base resin, since the durability of the resin composition is ensured to some extent, the amount of the light stabilizer can be reduced. Therefore, the problem of deterioration in brightness of the backlight unit can be improved.

The antistatic agent serves to prevent the application layer from being charged by eliminating space charges generated in the application layer 210. In addition, since the polypropylene resin has a high surface resistivity and is easy to be charged with static electricity, this causes dust to adhere, thereby degrading the aesthetics of the light diffusion plate 20 and lowering the lighting efficiency, thereby preventing the color of the lamp from changing. Can be used for

The antistatic agent may be applied in an amount of about 0.001 to 10 parts by weight, preferably about 0.005 to 5 parts by weight, based on 100 parts by weight of the polypropylene resin used as the base resin in the manufacture of the coating layer 210.

Examples of the antistatic agent include etherimideamide, polyetherester, polyetheresteramide, polyalkylene glycol, dodecyl benzenesulfonate alkali metal, tertiary amine, quaternary ammonium, salt, alkyl amine, and the like. One or two or more of the materials may be selected and used.

The ultraviolet absorber is used to block ultraviolet rays generated from the light source, and any ultraviolet absorber capable of absorbing wavelengths in the range of about 250 to 800 nm may be used.

For example, when the ultraviolet absorber having the maximum absorption wavelength is in the range of about 250 to 350 nm, the light resistance is improved, and the coloring of the light diffusion plate due to the ultraviolet absorption can be suppressed.

The ultraviolet absorber may be used in an amount of about 0.01 to 2 parts by weight based on 100 parts by weight of the polypropylene resin used as the base resin in the manufacture of the coating layer 210. In addition, specific examples of the ultraviolet absorber include a benzophenone series, a benzotriazole series, a cyanoacrylate series, a sarichileto series, a nickel complex salt series, and the like, and at least one of them can be used.

As described above, the light stabilizer, the antistatic agent, and the ultraviolet absorber may exhibit sufficient function even if mainly added only to the surface side of the light diffusion plate. Therefore, when they are added to the coating layer, from the viewpoint of the light diffusion plate 20 as a whole, it is understood that they are arranged in the surface layer, and thus exhibit sufficient function. Therefore, since only a small amount of light stabilizer, antistatic agent, ultraviolet absorber, etc. is added to the entire light diffusion plate 20, the manufacturing cost can be reduced.

The thickness of the coating layer 210 is not limited thereto, but may be about 10 to 1000 μm. Furthermore, the thickness of the coating layer 210 may be adjusted in the range of about 1/5 to 1/50 with respect to the thickness of the base layer 200. For example, the thickness of the coating layer 210 may be about 1/18 of the base layer 200.

The base layer 200 and the coating layer 210 are bonded to each other, adhered to each other by a method such as injection molding, extrusion molding, vacuum molding, hot press molding, coextrusion molding, film lamination, solvent bonding, or surface coating. Can be glued.

For example, a multi-layer extrusion method using a polishing roll will be described. For example, the materials used in the production of the substrate layer 200 and the coating layer 210 are kneaded.

Subsequently, the light diffusion plate 20 in which the coating layer 210 is laminated on one or both surfaces of the substrate layer 100 can be manufactured by supplying each to a feed block die or a multi-manifold die.

The light diffusing plate 20 according to some exemplary embodiments of the present invention may further include some additives within a range that does not affect the intrinsic properties of the light diffusing plate 20.

Applicable additives include blowing agents, other plasticizers, antioxidants, thermal stabilizers, lubricants, flame retardants, fillers, mold release agents, dyes, pigments, antibacterial agents, antidropping agents and nucleating agents that prevent appearance defects caused by yellowing due to resin degradation. And the like, and at least one of these can be used.

2 shows another embodiment of the light diffusion plate of the present invention.

2 is the same as the embodiment of FIG. 1 except that the coating layer 210 is formed on only one surface of the base layer 200 in comparison with the embodiment of FIG. 1. Therefore, in describing the embodiments illustrated in FIG. 2, the description of the light diffusion plate of FIG. 1 may be interpreted by referring to the description.

In the above description, the light diffusing plate of the present invention is separated into the base layer 200 and the coating layer 210, and only the case where they are combined as two members is described, but the base layer 200 and the coating layer 210 are one. It may be formed by fusing into a layer of.

That is, as described above, since the polypropylene resin layer of the base layer 200 and the polypropylene resin layer of the coating layer 210 are made of the same material, they are fused and formed into one polypropylene resin layer, When the light diffusing agent, the bubble, the embossing pattern 230, etc. are dispersed or formed at the position, the same effect as that of the light diffusing plate 20 described with reference to FIGS. 1 and 2 can be obtained.

The light diffusion plate 20 as described above may be applied to a backlight unit and a liquid crystal display including the same.

3 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention. 3 illustrates a backlight unit 50 including the light diffusion plate 20 of FIG. 1 and the liquid crystal display 70.

However, it is obvious that the light diffusion plates (eg, the light diffusion plate of FIG. 2) according to various embodiments of the present invention may be substituted.

Referring to FIG. 3, the liquid crystal display 70 includes a backlight unit 50 and a liquid crystal display panel 60.

The backlight unit 50 includes a light source 20 for generating light, a reflective sheet 30 for reflecting light emitted from the light source upwards, and a light diffusion plate 13 for diffusing light emitted from the light source 20. do. Although not shown, various optical sheets such as a prism sheet and a protective sheet may be further included on the light diffusion plate 13.

The liquid crystal display panel 60 includes two display substrates 61 and 62 facing each other with the liquid crystal layer 63 therebetween. The first display substrate 61 may include a plurality of thin film transistors (not shown) and pixel electrodes (not shown) arranged in a matrix. The second display substrate 62 may include a common electrode (not shown) and a color filter (not shown).

Further details, modifications, and the like of such a liquid crystal display are widely known in the art, and detailed descriptions thereof will be omitted to avoid ambiguity with the present invention.

More detailed information about the present invention will be described through the following specific preparation examples and experimental examples, the description is not described herein is omitted because it will be sufficiently technical inference to those skilled in the art.

<Manufacture example 1>

① Production of resin composition for base layer

To 100 parts by weight of polypropylene resin (Samsung Total, RS310), 2 parts by weight of silicon-based particles (silicon of GE Toshiba) having an average particle diameter of 2 µm and 2 parts by weight of acrylic crosslinked particles (Sekisui) having an average particle diameter of 8 µm are added. To prepare a resin composition for the base layer.

② Production of resin composition for coating layer

0.5 parts by weight of nitrogen, 1 part by weight of antistatic agent (Matsuda Garasu Kogyo, MX-50) and light stabilizer (Clariant, Hostavin PR-25) were added to 100 parts by weight of polypropylene resin (Samsung Total, RS310) and the resin for the coating layer The composition was prepared.

③ Fabrication of light diffusion plate

The resin composition for base layer and the resin composition for coating layer were put into each extruder, melted and kneaded, and then fed to a feed block die, whereby the coating layer / substrate layer / coating layer had a thickness of 100 μm / 1800 μm / 100 μm. A diffuser plate was prepared.

<Manufacture example 2>

A light diffusion plate was manufactured in the same manner as in Preparation Example 1, except that 2.5 parts by weight of nitrogen was added during the preparation of the resin composition for the coating layer.

<Manufacture example 3>

A light diffusion plate was manufactured in the same manner as in Preparation Example 1, except that 7.5 parts by weight of nitrogen was added during the preparation of the resin composition for the coating layer.

<Comparative Example 1>

Instead of the polypropylene resin of the resin composition for the base layer, styrene resin (PS JAPAN Co., Ltd.) was used, and a resin obtained by copolymerizing methyl methacrylate resin and styrene resin (DENKA Co., Ltd.) instead of the polypropylene resin of the coating layer resin composition. A light diffuser plate was manufactured in the same manner as in Preparation Example 1, except that 10 parts by weight of an acrylic light diffusing agent was added instead of nitrogen.

<Comparative Example 2>

A light diffusion plate was manufactured in the same manner as in Comparative Example 1 except that instead of the polypropylene resin of the resin composition for the base layer, a resin (DENKA Co., Ltd.) obtained by copolymerizing a methyl methacrylate resin and a styrene resin was used.

Experimental Example

With respect to the light diffusing plates prepared in Preparation Examples 1 to 3 and Comparative Examples 1 and 2, the amount of warpage and optical properties were evaluated by the following method.

(1) thermal deformation test

Each light diffuser plate was cut to 1040mm × 590mm × 2mm and fixed to a support, and then left for 24 hours in an oven at 90 ° C. and then the degree of warpage was visually observed.

(2) light resistance test

ATLAS-UVCON was used to irradiate ultraviolet rays at a temperature of 60 ° C. for 72 hours, and then a YI (Yellow Index) change was measured.

(3) Light transmittance, light scattering test

The light transmittance and the light scattering property of each light diffusing plate were measured by using a haze meter (NDH 5000W, Nippon Denim Co., Ltd.).

(4) luminance test

Each light diffuser plate was mounted in a 46-inch backlight, and then luminance was measured using a BM-7 luminance meter.

(5) visibility test

After attaching each light diffusion plate to a 32-inch backlight, the concealment of the cold cathode fluorescent lamp was visually observed.

Including the heat deformation test, the results for other tests are summarized in Table 1 below. However, the unit for measuring the following light resistance is ΔYI (difference of the yellew index before and after measurement), and the smaller the difference value, the better the light resistance.

Referring to Table 1, the light diffusing plates of Preparation Examples 1 to 3 molded of polypropylene resin showed values that are inferior to those of Comparative Examples in terms of light transmittance and luminance, and are particularly superior to Comparative Examples in terms of light scattering and light resistance. The value is shown.

In addition, the light diffusing plates of Preparation Examples 1 to 3 showed excellent results in visibility indicating whether or not bright lines were observed. From the above results, it can be seen that the light diffusing plate according to the embodiments of the present invention is excellent in all of heat distortion characteristics, light resistance, light transmittance, light scattering property, brightness, and visibility.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. I can understand that. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

1 is a perspective view of a light diffusing plate according to an embodiment of the present invention.

2 shows another embodiment of the light diffusion plate of the present invention.

3 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

Claims (17)

A substrate in which 0.1 to 10 parts by weight of a siloxane light diffusing agent having an average particle diameter of 1 to 20 μm and 0.1 to 10 parts by weight of an acrylic light diffusing agent having an average particle diameter of 1 to 20 μm are dispersed with respect to 100 parts by weight of polypropylene resin. layer; And It is laminated on one surface or both surfaces of the substrate layer, bubbles are formed therein, and an embossing pattern is formed on the surface of the surface opposite to the surface laminated with the substrate layer, with respect to 100 parts by weight of polypropylene resin. , Light diffusion plate consisting of a coating layer comprising 0.01 to 2 parts by weight of the ultraviolet absorber, 0.001 to 10 parts by weight of the antistatic agent. The method of claim 1, The weight average molecular weight of the polypropylene resin has a value of 100,000 or less, the scattering (Haze) is a light diffusion plate, characterized in that 50 or less on the basis of 2mm thickness. The method of claim 1, The coating layer further comprises an acrylic light diffusing agent having an average particle diameter of 1 ~ 50㎛. The method of claim 1, The coating layer further comprises a siloxane light diffusing agent having an average particle diameter of 1 ~ 20㎛. The method according to claim 1 or 4, The siloxane-based light diffusing agent is selected from a polydialkyl siloxane resin including polydimethyl siloxane and polydiethyl siloxane, and a silicone resin having a three-dimensional network structure including a siloxane having an epoxy at the end group. Light diffusion plate. The method of claim 1, The acrylic light diffusing agent is an acrylic monofunctional monomer, methacrylic acid esters including methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate and benzyl methacrylate; A light diffusion plate comprising at least one selected from acrylic esters including methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate and benzyl acrylate. The method of claim 1, The bubble is a light diffusion plate, characterized in that the diameter of 0.1 ~ 20㎛. The method of claim 1, The embossing pattern is a light diffusion plate, characterized in that the amorphous pattern having an average roughness of 0.1 ~ 10㎛. The method of claim 1, The ultraviolet light absorber is a light diffusion plate, characterized in that the material for absorbing ultraviolet light in the wavelength range of 250 ~ 800nm. The method of claim 9, The ultraviolet absorber is a light diffusion plate comprising at least one of benzophenone-based, benzotriazole-based, cyanoacrylate-based, sarichireto-based, nickel complex salt-based ultraviolet absorber. The method of claim 1, The antistatic agent is composed of at least one of polyetherimideamide, polyetherester, polyetheresteramide, polyalkylene glycol, dodecyl benzenesulfonate alkali metal, tertiary amine, quaternary ammonium, salt, alkyl amine system Light diffusion plate made with. The method of claim 1, The base layer and the coating layer are bonded to each other or adhered to each other by a method selected from the group consisting of injection molding, extrusion molding, vacuum molding, hot press molding, coextrusion molding, film lamination, solvent bonding and surface coating. Or a light diffusion plate, wherein the light diffusion plate is bonded. The method of claim 1, The thickness of the base layer is a light diffusion plate, characterized in that 100 ~ 10000㎛. The method of claim 1, The thickness of the coating layer is a light diffusion plate, characterized in that 10 ~ 1000㎛. The method of claim 1, The coating layer may further include one or two or more additives of a blowing agent, a plasticizer, an antioxidant, a heat stabilizer, a lubricant, a flame retardant, a filler, a release agent, a dye, a pigment, an antibacterial agent, an antidropping agent, a nuclear material, and the like. Light diffusion plate made with. A backlight unit of a liquid crystal display device comprising the light diffusion plate of claim 1. A liquid crystal display device comprising the backlight unit of claim 16.

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