KR100810685B1 - Light diffuser plate for lcd back light unit - Google Patents

Abstract

A light diffusion plate for a back light unit of an LCD(Liquid Crystal Display) device is provided to secure luster resistance by a multi-layered structure and to reduce the material cost by inserting a light diffusing agent and a luster resistant agent into each layer. A light diffusion plate(21) for a back light unit of an LCD device is composed of a base layer(200) and an applied layer(210) formed on one or both surfaces of the base layer. The base layer consists of a siloxane light diffusing agent of 0.1~10wt.% having a mean particle diameter of 1~20 micrometers and an acryl light diffusing agent of 0.1~10wt.% having a mean particle diameter of 1~20 micrometers to polycarbonate resin of 100wt.%. The applied layer has an embossing pattern on the surface and contains the acryl light diffusing agent of 0.1~30wt.% having a mean particle diameter of 1~50 micrometers to polycarbonate resin of 100wt.%.

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: base material layer 210: coating layer

The present invention relates to a light diffusion plate for a backlight unit of a liquid crystal display device, and more particularly, to a base resin made of a polycarbonate resin having high heat resistance instead of a polymethyl methacrylate resin or a polystyrene resin. The light emitted from the light source passes through the layer containing the light diffusing agent firstly and uniformly spreads, and the light diffusing agent and the surface embossed on the surface of the light diffuser secondly pass the light efficiency and The present invention relates to a light diffusion plate for a backlight unit of a liquid crystal display device having excellent light diffusivity and increasing brightness and having good weather resistance through a multilayer structure instead of a single layer structure.

Liquid crystal display device is not a self luminescence device such as plasma display panel (PDP) or organic light emission diode (OLED), but changes in liquid crystal according to a predetermined signal when surface light is incident on the back It refers to a device that displays the light passing through by adjusting the opening (close / open) of the passage in which the light moves.

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.

In addition, polymethyl methacrylate resin or polystyrene resin, which is mainly used in the related art, is weak in heat resistance and may cause warpage due to heat.

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.

The light diffusing plate for a backlight unit of the liquid crystal display device according to the embodiment of the present invention for solving the above technical problem is a siloxane-based light diffusing agent 0.1 having an average particle diameter of 1 ~ 20㎛ with respect to 100 parts by weight of polycarbonate resin A base layer comprising 0.1 to 10 parts by weight of an acrylic light diffusing agent having an average particle diameter of ˜10 parts by weight and 1 to 20 μm; And an embossed pattern having a predetermined shape formed on one surface or both surfaces of the substrate layer, and having an average particle diameter of 1 to 50 µm with respect to 100 parts by weight of polycarbonate resin. It consists of an application layer containing 30 parts by weight.

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 embodiment of the present invention are applied to an actual backlight unit. The base layer 200 is made of polycarbonate and has a matrix. The light diffusing agent is dispersed throughout the volume of the base resin.

The polycarbonate resin used as the base resin of the base layer 200 and the coating layer 210 includes a repeating unit represented by the following Chemical Formula 1 or Chemical Formula 2, and has a molecular weight (weight average molecular weight) of 5,000 or more.

(A and B is an element for substituting hydrogen of the benzene ring in the formula (1) and (2), a halogen group such as -F, -Cl, -Br, -I, alkyl group ((-CH ₃ ) _n ) and P and q have a value of 0 ~ 3.)

In particular, in the polycarbonate resin represented by the general formula (1), tetra is represented by the following general formula (3) in order to improve the compatibility when blending with hydrolysis resistance polyphenylene resin, polymethacrylic resin, polystyrene resin Methyl bisphenol A (tetramethylbisphenol A) -based polycarbonate resin (A and B in the formula 1 is CH ₃ , p and q value is 2) can be preferably used.

The polycarbonate resin used as the base resin in the base layer 200 and the coating layer 210 of the present invention is an aromatic polycarbonate resin which is generally used, and dihydroxyphenol and phosgene (carbonyl chloride; COCL _2). ) And chain and branch type carbonate homopolymers and polyester copolymers prepared by the reaction of dihydroxy phenol and carbonate precursors, or 1 Mixtures of species or more.

In this case, dihydroxy phenol is 2,2-bis (4-hydroxyphenyl) propane (2,2-Bis (4-hydroxyphenyl), also called bisphenol A), bis (4-hydroxy phenyl Bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane (2,2-Bis (4-hydroxy-3,5-dimethylphenyl) propane) And 1,1-bis (4-hydroxyphenyl) cyclohexane (1,1-Bis (4-hydroxyphenyl) cyclohexane) and the like, wherein the carbonate precursor is diphenyl carbonate, carbonyl halide ) And diaryl carbonates.

The polycarbonate resin described above is a material having strong heat resistance, scratch resistance, solvent resistance, and thickness dependency.To improve this, the polycarbonate resin is copolymerized with tere (iso) phthalic acid dichloride to formula (4). The polyester carbonate (PEC) shown can also be used.

However, in the present invention, the polycarbonate resin used as the base resin of the coating layer 200 and the base layer 210 may be used as long as the material includes at least one repeating unit represented by Formula 1 or Formula 2. .

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.

The acrylic light diffusing agent may be used by adjusting the refractive index by copolymerizing with the polycarbonate resin of the present invention, and when the phenyl or halogen group is large, the refractive index of the particles is generally increased.

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 to the polycarbonate resin, since the rubber component has great impact resistance and bending elastic modulus, the physical properties of the copolymerized polycarbonate resin are improved.

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 set to 10 ~ 1,000㎛, 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 ~ 10㎛ 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 also based on the polycarbonate resin described above, 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 polycarbonate resin used as the base resin for producing the coating layer 210 has the same configuration as that used for producing the base layer 200 described above, and other properties are also the same.

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. Also, since the polycarbonate-based resin has a high surface resistivity, it is easy to be charged with static electricity. Due to the dust attached, the appearance of the light diffusion plate is lowered and the lighting efficiency is lowered, which is used to prevent the color of the lamp from changing.

The antistatic agent is added in an amount of 0.001 to 10 parts by weight, preferably 0.005 to 5 parts by weight, based on 100 parts by weight of the polycarbonate 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 polycarbonate 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. To include the additives including any one or more of blowing agents, other plasticizers, antioxidants, heat stabilizers, lubricants, flame retardants, fillers, mold release agents, dyes, pigments, antibacterial agents, anti-dropping agents and nucleating agents are added to prevent the appearance defects It may be.

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 includes kneading the materials used in the respective production to manufacture the base layer 200 and the coating layer 210, and then feeding each of the feed block dyna multi It is a method of manufacturing the multilayer light-diffusion plate laminated | stacked in two layers or three layers by supplying to a 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 is not particularly limited because it depends on the intended use or required characteristics, but may be in a range of 10 μm to 1,000 μm. 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 so as 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 has a random pattern within 0.1 ~ 10㎛, this pattern is changed depending on the situation because it is fluid depending on the distance between the backlight lamp, the distance between the diffuser and the lamp, the brightness of the lamp.

The multi-layered light diffuser plate finally prepared according to the present invention is a spherical siloxane-based light diffusing agent and an acryl-based excellent in light diffusion and light transmittance on the base layer 200 made of a polycarbonate resin specially manufactured to improve heat resistance and optical properties. Using a diffusing agent and externally adding an acrylic light diffusing agent, a light stabilizer, an antistatic agent, and an ultraviolet ray shielding agent to the coating layer 210 to effectively cope with the yellowing phenomenon caused by ultraviolet rays and heat generated in several lamps, It also prevents dust from adhering, which makes the display quality of LCD TVs excellent.

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, the light diffusing plate for the liquid crystal display device backlight unit according to the embodiments of the present invention will be described with reference to specific embodiments that the bending property, light resistance, light transmittance, light scattering property, and brightness are very excellent. However, the content not described herein is omitted because it can be inferred technically sufficient by those skilled in the art.

One. Examples  And Comparative Examples

< Example  1>

① production of base layer;

100 parts by weight of polycarbonate resin (LG-DOW Polycarbonate, CALIBER 300-10), 1 part by weight of silicon-based particles having a mean particle size of 2 μm (GE Toshiba Silicone Co., Ltd.) and acrylic crosslinked particles having a mean particle size of 8 μm (Sekisui Co., Ltd.) Was prepared by adding 1 part by weight. (First resin composition)

② preparation of a coating layer;

To 100 parts by weight of a polycarbonate resin (LG-DOW Polycarbonate, CALIBER 300-10), 5 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 prepared. (2nd resin composition)

③ manufacture of a multilayer light diffuser plate;

In order to laminate the coating 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 to be melted and kneaded. Subsequently, the feed block die was fed to produce a three-layered multilayer light diffusing plate having a thickness of 100 μm / 1800 μm / 100 μm.

<Comparison Example  1>

Methyl methacrylate resin (Mitsubishi Rayon, Inc.) was used as the resin used in the production of the base layer and the coating, and was carried out in the same manner as in Example 1 except for the above.

<Comparison Example  2>

Styrene-based resin (PS Japan) was used as the base resin of the base layer, and the same procedure as in Example 1 was performed except that methyl methacrylate-based resin (Mitsubishi Rayon) was used as the base resin of the coating layer. It was.

Table 1 shows the specification of Example 1 and Comparative Examples 1 and 2 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.

2. Evaluation of Physical Properties

For 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.

Each test condition is as follows.

(1) heat deformation acceleration test

One side of the sample cut to 20 mm x 20 mm x 2 mm was fixed and left for 10 minutes in a convection oven at 110.degree. C. The amount of warpage was measured. At this time, the amount of warpage was measured on the table and the distance from the plate was measured.

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

3. Analysis of property evaluation results

Table 2 below shows the results of evaluating the physical properties of the Examples and Comparative Examples 2 prepared above.

From the results in Table 2, it can be seen that in the case of Example 1 molded from polycarbonate resin, the amount of deformation with respect to heat is the smallest. Specifically, in Example 1, the amount of warpage was only about 0.05 mm, but the comparison was performed. Example 1 In the comparative example 2, the amount of warpage of 2-3 mm was shown.

In addition, when using the polycarbonate resin like the present invention in terms of light transmittance, light scattering property, and luminance, the values were almost the same as those using methyl methacrylate resin or polystyrene resin.

Based on the above results, when the polycarbonate resin is used as the base resin as in the present invention, it is possible to manufacture the light guide plate for the liquid crystal display device backlight unit with enhanced heat resistance while maintaining the same level of optical properties.

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 rather than a single layer structure, and by putting the light diffusing agent and light-resistant agent in each layer separately, it is possible to reduce the material cost by increasing the light diffusion efficiency and light resistance.

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 polycarbonate resin, the light diffusion plate excellent in heat resistance can be manufactured.

Claims (18)

A substrate comprising 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, based on 100 parts by weight of polycarbonate resin. layer; And It is laminated on one side or both sides of the base layer, the embossing pattern is formed on the surface, and contains 0.1 to 30 parts by weight of an acrylic light diffusing agent having an average particle diameter of 1 to 50㎛ with respect to 100 parts by weight of polycarbonate resin. Coating layer; Light diffusion plate for a liquid crystal display backlight unit comprising a. The method of claim 1, The polycarbonate resin includes a repeating unit represented by the following Chemical Formula 1 or Chemical Formula 2, and has a molecular weight of 5,000 or more.

(A, B is an element substituted for hydrogen in the benzene ring, selected from a halogen group element or an alkyl group (-CH ₃ ) n, p and q has a value of 0-3.) The method of claim 2, Wherein A and B is a methyl group (-CH ₃ ), p and q value of the light diffusion plate for a backlight unit of the liquid crystal display device, characterized in that represented by the following formula (3).

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 according to claim 1 or 4, 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 including 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 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, And the coating layer further comprises 0.01 to 2.0 parts by weight of an ultraviolet absorber based on 100 parts by weight of the polycarbonate resin. The method of claim 7, wherein The ultraviolet absorber is a light diffusion plate for a liquid crystal display device backlight unit, characterized in that the ultraviolet absorber for absorbing ultraviolet light in the wavelength range of 250 ~ 800nm. The method according to claim 7 or 8, The ultraviolet absorber is a light diffusion plate for a backlight unit of the liquid crystal display device, characterized in that it comprises at least one of benzophenone-based, benzotriazole-based, cyanoacrylate-based, sarichireto-based, nickel complex salt-based ultraviolet absorber. The method of claim 1, And the coating layer further comprises 0.001 to 10 parts by weight of an antistatic agent based on 100 parts by weight of the polycarbonate resin. The method of claim 10, The antistatic agent includes at least one of polyetherimideamide, polyetherester, polyetheresteramide, polyalkylene glycol, dodecyl benzenesulfonate alkali metal, tertiary amine, quaternary ammonium, salt and alkyl amines. An optical diffusion plate for backlight units of a liquid crystal display device. The method of claim 1, The base layer and the coating layer are each 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. 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, The embossing pattern formed on the surface of the coating layer 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 ~ 10㎛. 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 nucleating agent, and the like. Display Diffusion plate for backlight unit. 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 17.

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