KR100893520B1 - Light diffuser plate for LCD back light unit - Google Patents

Abstract

A light diffusion plate for a backlight unit of a liquid crystal display device is provided. The light diffusing plate for the backlight unit of the liquid crystal display device has a siloxane light having an average particle diameter of 1 to 20 μm based on 100 parts by weight of the base resin in which the methacrylic acid-styrene copolymer and the methyl methacrylate copolymer are mixed. A substrate layer comprising 0.1 to 10 parts by weight of a diffusing agent, 0.1 to 10 parts by weight of an acrylic light diffusing agent having an average particle diameter of 1 to 20 μm, and a methyl methacrylate copolymer laminated on one or both sides of the substrate layer. It consists of an application layer containing 0.1-30 weight part of acrylic light-diffusing agents which have an average particle diameter of 1-50 micrometers, 0.01-2 weight part of ultraviolet absorbers, and 0.001-10 weight part of antistatic agents with respect to 100 weight part of resin.

LCD, backlight unit, light diffusing plate, porous light diffusing agent, amorphous, embossing, irregularities, methacrylic acid, styrene

Description

Light diffuser plate for LCD back light unit of liquid crystal display device

1 is a cross-sectional view showing a direct backlight unit.

2 is a perspective view illustrating a light diffusion plate for a backlight unit of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a perspective view illustrating a light diffusion plate for a backlight unit of a liquid crystal display according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

200: substrate layer: coating layer

The present invention relates to a light diffusing plate for a backlight unit of a liquid crystal display device, and more specifically, to a methacrylic acid resin, which is used in the prior art, from a light source in a base resin mixed with a styrene resin having high heat resistance and resistance to warping. The light is first spread through the layer containing the light diffusing agent and uniformly diffuses, and secondly, the light diffusing agent and the surface embossed on the surface of the light diffuser and light diffusivity compared to the existing diffuser plate. The present invention relates to a light diffusing plate for a backlight unit of a liquid crystal display device that has excellent brightness, increases brightness, and has good weather resistance through a multilayer structure rather than a single layer structure.

A liquid crystal display device is not a self-emitting device such as a plasma display panel (PDP) or an organic light emission diode (OLED), but a change in liquid crystal according to a predetermined signal when a surface light is incident from the rear side. According to this means to control the opening and closing of the passage (light / light) moving, the device that displays the light passing through.

As such, since the liquid crystal display is not a self-luminous element, the liquid crystal display requires a device called a backlight unit on its rear surface. The backlight unit of the liquid crystal display may be divided into an edge type and a direct type. The double edge type is mainly used for a notebook computer or a desktop computer monitor, and the direct type is mainly used for a large area such as an LCD TV.

1 is a cross-sectional view showing a direct backlight unit.

As shown in FIG. 1, the direct backlight unit 10 includes a fluorescent lamp 100 for generating light, a reflector 110 for reflecting the generated light in a direction in which the panel is located, and a light diffusion plate 120. Include.

The reason why the backlight unit 10 illustrated in FIG. 1 is called a direct type is that the fluorescent lamp 100 is not positioned at the side of the backlight unit 10 but is perpendicular to the surface where the actual image information is displayed. Because it is located.

There is a light diffusion plate 120 in the direct type backlight unit 10, the light diffusion plate 120 scatters the light generated from the fluorescent lamp 100 to uniformize the light in the entire panel Play a role.

The light diffusion plate 120 is mainly used as a transparent resin, such as methacrylic resin, styrene resin, cyclic olefin resin, polycarbonate resin, and is prepared by adding a light diffusing agent, The light diffusing agent has a light transmission effect that transmits direct light or fluorescent light with high transmittance, a hiding power such that the light source is not visible to the naked eye, and a light diffusion effect that diffuses the light.

However, in recent years, such as a large LCD TV, a large number of lamps are mounted in order to realize high brightness, and thus, the amount of heat generated from the lamps increases, which causes thermal deformation of the light diffusion plate.

Methacrylic or styrene-based resins, which are used as basic resins for light diffusion plates, have excellent optical properties, but are vulnerable to thermal deformation. Polycarbonate or olefin resins have relatively high cost and are inferior in formability and optical properties. .

In addition, as a diffusing agent, an inorganic material or an organic material having a difference in refractive index of 0.02 to 0.13 is generally used. The inorganic fine particles are calcium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, silica, glass, talc. , Mica, white carbon, magnesium oxide, zinc oxide, and the like, and silicon-based, teflon-based, acrylic-based, styrene-based, etc. are used as the organic fine particles.

Conventional techniques for such a light diffusion plate include the following.

Japanese Laid-Open Patent Publication No. 9-31288 discloses a composition in which 0.2-10 parts by weight of precipitated calcium carbonate having a methacrylic base resin having an average particle diameter of 1 to 15 µm and a hexahedral structure is added.

Japanese Laid-Open Patent Publication No. 11-35779 discloses a composition in which barium sulfate, calcium carbonate, talc, and the like are used as a methacrylic resin as a base resin, and a small amount of additives such as an ultraviolet absorber and a light stabilizer are disclosed.

However, when the light diffusing plate is manufactured using the composition used in the above-described technology and the conventional light diffusing plate, agglomeration occurs between particles having a large particle diameter and light is transmitted through the light diffusing plate. When spreading, there is a fear that a problem of spots occurs. In particular, when an inorganic substance is used as the light diffusing agent, the inorganic light diffusing agent is hardly uniformly dispersed in the transparent thermoplastic resin used as the matrix, and the light efficiency is also remarkably low, making it unsuitable for use in display devices. In addition, according to the hardness of the inorganic light diffusing agent, the manufacturing equipment may be worn or damaged, and die lines are produced due to the inorganic light diffusing agent when the molded article is manufactured.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a light diffusion plate for a backlight unit of a liquid crystal display device having excellent light diffusivity and low heat resistance and manufacturing cost in response to an enlargement of an LCD panel.

Technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above technical problem, a light diffusion plate for a backlight unit of a liquid crystal display according to an exemplary embodiment of the present invention includes 100 parts by weight of a base resin in which a methacrylic acid-styrene copolymer and a methyl methacrylate methyl-styrene copolymer are mixed. A base layer comprising 0.1 to 10 parts by weight of a siloxane light diffusing agent having an average particle diameter of 1 to 20 μm, an acrylic light diffusing agent having an average particle diameter of 1 to 20 μm, and a base layer of 0.1 to 30 parts by weight of acrylic light diffusing agent, 0.01 to 2 parts by weight of ultraviolet absorber, charged on one side or both sides, and having an average particle diameter of 1 to 50 µm with respect to 100 parts by weight of methyl methacrylate-styrene copolymer resin It consists of an application layer containing 0.001-10 weight part of inhibitors.

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

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 may be implemented in various different forms, only the present embodiments to make the disclosure of the present invention complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

In addition, in the drawings, the size and thickness of layers and films or regions are exaggerated for clarity of description, and when any film or layer is described as being formed "on" of another film or layer, It may be directly on top of the other film or layer, and a third other film or layer may be interposed therebetween.

2 and 3 are cross-sectional views illustrating a light diffusion plate for a backlight unit of a liquid crystal display according to an exemplary embodiment of the present invention.

2 and 3, the light diffusion plates 20 and 21 for the backlight unit of the liquid crystal display according to the exemplary embodiment of the present invention include a base layer 200 and an application layer 210.

However, if the base layer 200 and the coating layer 210 each include at least one or more layers, the same or similar effects as the present invention can be obtained. However, if necessary, both sides of the base layer 200 are provided as shown in FIG. 2. The coating layer 210 may be combined, or as shown in FIG. 3, the base layer 200 and the coating layer 210 may be combined 1: 1. In addition, the light diffusion plates 20 and 21 illustrated in FIG. 2 or 3 may be laminated and used as necessary.

The base layer 200 serves as a support layer when the light diffusion plates 20 and 21 according to the exemplary embodiment of the present invention are applied to the actual backlight unit. The methacrylic acid-styrene copolymer and the methyl methacrylate methyl-styrene copolymer What is mixed is used as a matrix, and the light-diffusing agent is disperse | distributed throughout the volume of a basic resin here.

The methacrylic acid-styrene copolymer used as the base resin of the base layer 200 has a composition range consisting of 2 to 20 parts by weight of methacrylic acid units and 80 to 98 parts by weight of styrene units, preferably methacrylic acid unit 5 10 parts by weight and 90 to 95 parts by weight of styrene units. In addition, the weight average molecular weight of the methacrylic acid-styrene copolymer has a value of 200,000 to 350,000 when converted based on polystyrene.

The methyl methacrylate styrene copolymer used as the base resin of the base layer 200 has a composition range consisting of 6 to 94 parts by weight of methyl methacrylate units and 6 to 94 parts by weight of styrene units, preferably methacryl. 20 to 80 parts by weight of the methyl acid unit and 20 to 80 parts by weight of the styrene unit. In addition, the weight average molecular weight of the methyl methacrylate styrene copolymer has a value of 70,000 to 300,000 when converted based on polystyrene.

The methacrylic acid-styrene copolymer and the methacrylic acid methyl-styrene copolymer constituting the base resin of the base layer 200 may be mixed by known techniques such as emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization.

In the base layer 200, a light diffusing agent is dispersed throughout the volume of the base resin, and as the light diffusing agent used, a siloxane light diffusing agent and an acrylic light diffusing agent are used.

The siloxane-based light diffusing agent is a siloxane-based crosslinking particle, and includes both silicone rubber having a low crosslinking density and flexibility as a silicone-based resin particle solid at room temperature, 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 epoxy in the terminal group.

Since the siloxane-based crosslinked particles have 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, the siloxane-based light diffusing agent has a refractive index of about 1.40 ~ 1.43 lower than other organic cross-linking particles have the advantage that the light diffusion and light transmittance equivalent to that of other light diffusing agents can be obtained even if only a small amount is added.

The siloxane light diffusing agent used in the present invention is spherical crosslinked fine particles having an average diameter of 1 to 20 µm, and 0.1 to 10 parts by weight based on 100 parts by weight of the resin of the base layer 200 used as the base resin. Is added.

The acrylic light diffusing agent is an acrylic spherical crosslinked particle having a refractive index of about 1.46 to 1.56, and is an acrylate monofunctional monomer such as ethyl methacrylate, methyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, and methacrylic acid. Methacrylic acid esters such as phenyl methacrylate and benzyl methacrylate; Acrylic esters, such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, and benzyl acrylate, etc. are mentioned, Two or more types can also be used as needed.

Acrylic light diffusing agent can be used by controlling the refractive index through copolymerization with methacryl-based alone or styrene-based, and the refractive index of the particles is usually higher when the phenyl or halogen group has a lot.

The acrylic light diffusing agent used in the present invention is spherical crosslinked particles having an average particle diameter of 1 to 20 µm, and 0.1 to 10 parts by weight is added to 100 parts by weight of the resin of the base layer 200 used as the base resin.

The base layer 200 of the light diffusion plates 20 and 21 according to the embodiment of the present invention may further include an impact modifier in addition to the basic resin and the light diffusing agent described above.

The impact modifier preferably includes rubber components such as acrylic rubber, butadiene rubber, and the like, but is not limited thereto.

When the rubber component is copolymerized with the methacryl resin, the rubber component has great impact resistance and bending elastic modulus, thereby improving physical properties of the copolymerized methacrylic resin.

And it is preferable that the thickness of the base material layer 200 is 100-10,000 micrometers.

The coating layer 210 may be formed only on one surface of the substrate layer 200 (see FIG. 3), or may be laminated on both surfaces of the substrate layer 200 (see FIG. 2).

The base layer 200 and the coating layer 210 are bonded to each other by a method such as injection molding, extrusion molding, vacuum molding, hot press molding, coextrusion molding, film lamination, solvent bonding, surface coating, or the like. It is characterized in that the adhesive or adhered.

The coating layer 210 has an amorphous embossing pattern formed on the surface of the substrate layer 200 in order to further scatter and diffuse light scattered and diffused through the porous light diffusing agent, and sometimes to collect light.

As shown in FIG. 2, the coating layer 210 may be hardened on only one surface of the substrate layer 200, and as shown in FIG. 3, the coating layer 210 may be laminated on both surfaces of the substrate layer 200. It may be.

The thickness of the coating layer 210 is preferably 10 to 1000 μm, and the embossing pattern formed on the surface of the coating layer 210 is an amorphous embossing pattern having an average roughness of about 0.1 to 20 μm. It is.

As such, the reason for forming the amorphous embossing pattern on the surface of the coating layer 210 is that the light diffused by the light diffusing agent in the substrate layer 200 has a constant direction through the amorphous embossing pattern in the coating layer 210. This is to increase light transmittance and light diffusivity by scattering and diffusing light in various directions, thereby increasing the overall average brightness.

The coating layer 210 is based on methyl methacrylate-styrene copolymer resin, and includes an acrylic light diffusing agent, a light stabilizer, and an antistatic agent. In addition, an ultraviolet absorber may be further included to block ultraviolet rays emitted from the light source.

The composition ratio of the methyl methacrylate-styrene copolymer resin used as the base resin for manufacturing the coating layer 210 has the same configuration as that used for preparing the base layer 200 described above, and the other properties are also the same. Do.

The acrylic light diffusing agent used in the manufacture of the coating layer 210 is the same as that used in the preparation of the base layer 200, and contains 0.1 to 30 parts by weight based on 100 parts by weight of the base resin of the coating layer.

The acrylic light diffuser is acrylic light diffuser in a range that does not significantly reduce light transmittance and light diffusivity in order to adjust the feel of a matte or the like having a white or irregular surface on the surface of the coating layer 210 and to increase design. Use the agent. The refractive index of the acrylic light diffuser is about 1.46 ~ 1.56 and the average particle radius is 1 ~ 50㎛.

In addition, the coating layer 210 may further include a siloxane light diffusing agent used for manufacturing the base layer 200 in addition to the acrylic light diffusing agent.

The light stabilizer functions to further enhance the durability of the resin composition by capturing free radicals. Hindered amines are used, and the light stabilizer may be used in a range that does not impair the physical properties of the present invention in parallel with the ultraviolet absorber.

The antistatic agent prevents the coating layer 210 from being charged by eliminating space charges generated in the coating layer 210. In addition, the methyl methacrylate-styrene copolymer resin has high surface resistivity and thus is charged with static electricity. Because of this, it is used to prevent dust and the like attached to the light diffusion plate to reduce the aesthetics of the light diffusion plate, and eventually the color of the lamp changes.

The antistatic agent is added in an amount of 0.001 to 5 parts by weight, preferably 0.005 to 5 parts by weight, based on 100 parts by weight of the methyl methacrylate styrene resin used as the base resin in the manufacture of the coating layer 210.

Specifically used antistatic agents include at least one of etherimideamide, polyetherester, polyetheresteramide, polyalkylene glycol, dodecyl benzenesulfonic acid alkali metal, tertiary amine, quaternary ammonium, salt, alkyl amine Is used.

UV absorbers are used to block ultraviolet rays generated from the light source. Any UV absorber that can absorb wavelengths in the range of 250 to 800 nm can be used. Especially, the maximum absorption wavelength is in the range of 250 to 320 nm. It is preferable because it improves the light resistance of and can suppress the coloring of the diffusion plate due to ultraviolet absorption. Specifically, one containing at least one of a benzophenone-based, benzotriazole-based, cyanoacrylate-based, sarichireto-based, nickel complex salt-based ultraviolet absorber may be used.

It is preferable that a ultraviolet absorber contains 0.01-2 weight part with respect to 100 weight part of methyl methacrylate styrene resins.

The light diffusing plates 20 and 21 according to the embodiment of the present invention may further include an additive within a range that does not affect the intrinsic properties of the light diffusing plates, which are caused by yellowing due to deterioration of the resin. An additive including a blowing agent, another plasticizer, an antioxidant, a heat stabilizer, a lubricant, a flame retardant, a filler, a mold release agent, a dye, a pigment, an antibacterial agent, an antidropping agent, and a nucleating agent may be further included to prevent the appearance defect. have.

In order to manufacture a light diffusing plate according to an embodiment of the present invention, a thermoplastic such as injection molding, extrusion molding, vacuum molding, heat press molding, and coextrusion molding may be used according to the purpose of the light diffusing plate which is specifically used by mixing the above-described raw materials. Both methods of molding the resin can be used.

Among them, a multilayer extrusion molding method having a polishing roll is preferable. The multilayer extrusion molding method involves kneading the materials used in the respective production to prepare the base layer 200 and the coating layer 210, and then feed each of the feed block dynas. It is a method of manufacturing the multilayer light-diffusion plate laminated | stacked in two layers or three layers by supplying to a multi manifold die and laminating | stacking.

As described above, the coating layer 210 may be laminated on one side or both sides of the base layer 200, and the thickness thereof may vary depending on the intended use or required characteristics, but is not particularly limited thereto. It is preferable to laminate | stack to the thickness of and it is more preferable to laminate | stack to the thickness of 10-100 micrometers.

As described above, an uneven surface such as an embossed pattern is formed on the coating layer 210. To form such an uneven surface, various methods such as press working, UV resin coating after processing, and contact processing in which an uneven pattern is formed on a polishing roll are formed. However, in view of the mass productivity of the light diffusion plate, polishing roll processing is most preferred.

Polishing roll patterns used for surface irregularities are averaged to uniformly scatter light scattered from several lamps mounted on the backlight, and to prevent the lamp line from being visible due to the scattered light. Roughness will have a random pattern within 0.1 ~ 20㎛, this pattern is changed depending on the situation because it is flexible depending on the distance between the backlight lamp, the distance between the diffuser and the lamp, the brightness of the lamp.

The multilayer light diffusing plate finally manufactured according to the present invention has a light on the base layer 200 in which a methacrylic acid-styrene copolymer and a methyl methacrylate methyl-styrene copolymer are specially manufactured to improve heat resistance and optical properties. A spherical siloxane light diffusing agent and an acrylic diffusing agent having excellent diffusivity and light transmittance are used, and externally, an acrylic light diffusing agent, a light stabilizer, an antistatic agent, and an ultraviolet ray shielding agent are added to the coating layer 210 in several lamps. It effectively copes with yellowing caused by ultraviolet rays and heat generated and prevents dust from adhering to static electricity, thus improving the display quality of LCD TVs.

Furthermore, since the organic light diffusing agent is used rather than the conventional light diffusing plate using only the inorganic light diffusing agent, the multi-layer light diffusing plate manufacturing equipment is less worn and damaged, and the light diffusing agent is evenly dispersed to prevent aggregation between the particles. In addition, the use of a porous light diffusing agent increases the scattering properties to reduce the amount of use of the light diffusing agent, it is possible to reduce the manufacturing process cost by using an antistatic agent and a light stabilizer only on the surface layer.

Hereinafter, specific embodiments of the present invention will be described.

< Example  1>

① production of base layer;

2 parts by weight of silicon-based particles (GE Toshiba Silicone Co., Ltd.) having an average particle diameter of 2 µm and 100 parts by weight of a resin in which a methacrylic acid-styrene copolymer and a methyl methacrylate copolymer were mixed, and an acrylic type having an average particle diameter of 8 µm. It was prepared by adding 2 parts by weight of crosslinked particles (Sekisui, Inc.).

② preparation of a coating layer;

10 parts by weight of acrylic crosslinked particles (Sekisui Co., Ltd.) having an average particle diameter of 20 μm, 1 part by weight of an antistatic agent and a light stabilizer were respectively added to 100 parts by weight of the resin in which the methyl methacrylate-styrene copolymer was mixed.

③ manufacture of a multilayer light diffuser plate;

In order to laminate the application layer made of the second resin composition on both sides of the base material layer made of the first resin composition, the prepared first resin composition and the second resin composition were introduced into each extruder, melted and kneaded, By supplying the feed block die, a three-layer structured multi-layer diffuser plate having a thickness of 100 µm / 1800 µm / 100 µm was applied.

<Comparison Example  1>

Styrene-based resin (PS JAPAN Co., Ltd.) was used as the resin used to prepare the coating layer 210, except that the above-mentioned contents were carried out in the same manner as in Example 1.

<Comparison Example  2>

Methyl methacrylate resin (Mitsubishi Rayon Co., Ltd.) was used as the base layer 200 resin, except for the above contents.

<Comparison Example  3>

Styrene-based resin (PS JAPAN Co., Ltd.) was used for the base layer 200 resin, and the same procedure as in Example 1 was performed except for the above-mentioned contents.

Table 1 shows the specifications of Example 1 and Comparative Examples 1, 2, and 3 above.

However, in Table 1, a ₁ : base material layer resin, a ₂ : silicon light diffusing agent / acrylic light diffusing agent, b ₁ : coating layer resin, b ₂ : acrylic light diffusing agent, b ₃ : antistatic agent / light stabilizer Represent each.

With respect to the specimens prepared as described above, the amount of warpage and the optical properties were evaluated by the following method, and the measurement results are shown in Table 2 (Weight Test) and Table 3 (Optical Test).

Each test condition is as follows.

(1) Sag test

One side of the sample cut to 50 mm x 30 mm x 2 mm was fixed, and the amount of warpage was measured after standing in an oven at 110 ° C for 1 hour.

(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 light scattering property of the multilayer board were measured by Haizumi (NDH 5000W, Nippon Denshi Kogyo Co., Ltd.).

(4) luminance test

A diffuser plate was mounted on a 32 inch backlight and measured using a BM-7 luminance meter.

Table 2 shows Sag test results of the Examples and Comparative Examples. From the results of Table 2, it can be seen that the resin of Example 1 molded from a resin in which a methacrylic acid-styrene copolymer and a methyl methacrylate methyl-styrene copolymer were mixed has the least amount of deformation with respect to heat. In Example 1, the amount of warpage was only about 1 mm, but in Comparative Examples 1 to 3, the warpage amount was 6 mm or more, and in Comparative Example 3, the warpage amount was 13 mm or more.

Table 3 shows the light resistance and optical property test results of the Examples and Comparative Examples.

From the results in Table 3, the resin of Example 1 molded from a resin in which a methacrylic acid-styrene copolymer and a methyl methacrylate methyl-styrene copolymer were mixed is inferior to the comparative example in terms of light transmittance, light scattering property, and brightness. While showing a value that does not, in terms of light resistance, it can be seen that the value is superior to the comparative examples. However, the unit for measuring light resistance at this time is ΔYI (difference of the yellew index before and after measurement), and the smaller the difference value, the better the light resistance.

The light diffusion plates 20 and 21 manufactured according to the present invention may be used in the backlight unit of the liquid crystal display device, and the liquid crystal display device may be manufactured using the backlight unit.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above embodiments and can be manufactured in various forms, and a person of ordinary skill in the art to which the present invention belongs. It will be appreciated that the present invention may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the light diffusing plate for the backlight unit of the liquid crystal display according to the embodiment of the present invention, one or more of the following effects exist.

First, by forming an amorphous embossing pattern on the surface it is possible to manufacture a light diffusing plate with improved light transmittance, light diffusion.

Second, it is excellent in light resistance by manufacturing a light diffusion plate in a multi-layer structure, not a single layer structure.

Third, because the organic light diffusing agent is used instead of the conventional inorganic light diffusing agent, less wear and damage to the light diffusing plate manufacturing equipment.

Fourth, by using a resin in which a methacrylic acid-styrene copolymer and a methyl methacrylate methyl-styrene copolymer are mixed, it is possible to manufacture a light diffusion plate having excellent heat resistance and light diffusivity.

Claims (17)

0.1 to 10 parts by weight of a siloxane light diffusing agent having an average particle diameter of 1 to 20 µm, based on 100 parts by weight of the base resin in which the methacrylic acid-styrene copolymer and the methyl methacrylate methyl-styrene copolymer are mixed. A base layer comprising 0.1 to 10 parts by weight of an acrylic light diffusing agent having an average particle diameter of μm; And 0.1-30 weight part of acrylic light-diffusion agents and an ultraviolet absorber 0.01-2 which have an average particle diameter of 1-50 micrometers with respect to 100 weight part of methyl methacrylate copolymer resins laminated | stacked on one side or both surfaces of the said base material layer. Light diffusion plate for a backlight unit of a liquid crystal display element which consists of a coating layer containing a weight part and 0.001-10 weight part of antistatic agents. The method of claim 1, The methacrylic acid-styrene copolymer, 2 to 20 parts by weight of methacrylic acid units and 80 to 98 parts by weight of styrene units, the light diffusion plate for a backlight unit of a liquid crystal display device. The method of claim 1, The methyl methacrylate-styrene copolymer is a light diffusion plate for a backlight unit of a liquid crystal display device, characterized in that consisting of 6 to 94 parts by weight of methyl methacrylate units and 6 to 94 parts by weight of styrene units. The method of claim 1, The coating layer further comprises a siloxane light diffusing agent having an average particle diameter of 1 ~ 20㎛ the light diffusion plate for a backlight unit of the liquid crystal display device. The method of claim 1, The siloxane-based light diffusing agent is a liquid crystal display device having a three-dimensional network structure including a polydimethyl siloxane, a polydialkyl siloxane resin such as polydiethyl siloxane, and a siloxane having an epoxy at the end group. Diffusion plate for backlight units. The method of claim 1, The acrylic light diffusing agent is an acrylic monofunctional monomer, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate and benzyl methacrylate; A light diffusion plate for a backlight unit of a liquid crystal display device, characterized in that it is selected from acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, and benzyl acrylate. The method of claim 1, The ultraviolet light absorber is a light diffusion plate for a liquid crystal display device backlight unit, characterized in that for absorbing ultraviolet light in the wavelength range of 250 ~ 800nm. The method of claim 1, The ultraviolet absorber is selected from benzophenone-based, benzotriazole-based, cyanoacrylate-based, sarichileto-based, nickel complex salt-based ultraviolet absorber, the light diffusion plate for a backlight unit of the liquid crystal display device. The method of claim 1, The antistatic agent is selected from polyetherimideamide, polyetherester, polyetheresteramide, polyalkylene glycol, dodecyl benzenesulfonic acid alkali metal, tertiary amine, quaternary ammonium, salt, alkyl amine Light diffusion plate for backlight unit of liquid crystal display device. The method of claim 1, The base layer and the coating layer are bonded, adhered or adhered to each other by injection molding, extrusion molding, vacuum molding, hot press molding, coextrusion molding, film lamination, solvent bonding, or surface coating. A light diffusion plate for a backlight unit of a liquid crystal display device, characterized in that. The method of claim 1, The thickness of the base layer is a light diffusion plate for a backlight unit of the liquid crystal display device, characterized in that 100 ~ 10,000㎛. The method of claim 1, The thickness of the coating layer is a light diffusion plate for a backlight unit of the liquid crystal display device, characterized in that 10 ~ 1,000㎛. The method of claim 1, An embossing pattern having a predetermined shape is formed on a surface of the coating layer, the light diffusion plate for a backlight unit of a liquid crystal display device. The method of claim 13, The embossing pattern is a light diffusing plate for a backlight unit of the liquid crystal display device, characterized in that the amorphous pattern having an average roughness of 0.1 ~ 20㎛. The method of claim 1, The coating layer further comprises an additive selected from a blowing agent, a plasticizer, an antioxidant, a heat stabilizer, a lubricant, a flame retardant, a filler, a mold release agent, a dye, a pigment, an antibacterial agent, an antidropping agent, and a nuclear material. Light diffuser plate for device backlight unit. A backlight unit of a liquid crystal display device comprising the light diffusion plate of any one of claims 1 to 15. A liquid crystal display device comprising the backlight unit of claim 16.

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