KR101127106B1 - Light diffuser used in liquid crystal display device - Google Patents

Abstract

It is 0.05 to 1.00 parts by weight based on 100 parts by weight of polycarbonate resin is benzotriazole-based first ultraviolet stabilizer to absorb ultraviolet rays in the 280nm to 300nm wavelength range than other wavelength bands, and 0.05 to 1.00 weight based on 100 parts by weight of polycarbonate resin The present invention provides a light diffusion plate of a liquid crystal display device including a hydroxyphenyl triazine-based second ultraviolet stabilizer, which is included and absorbs ultraviolet rays in the 300 nm to 320 nm wavelength band more predominantly than other wavelength bands.

Diffuser plate, LCD, Diffuser, UV stabilizer, Color coordinate

Description

Light diffuser used in liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device, and more particularly, to a light diffusion plate for a back light unit, which absorbs an ultraviolet B wavelength band.

Liquid crystal display device (Liquid crystal display device) is a device that displays the light passing by controlling the opening / closing of the light moving path according to the change of the liquid crystal according to a predetermined signal when the surface light is incident on the rear surface. . As such, since the liquid crystal display is not a self-luminous element, a surface light source such as a backlight unit is required at the rear thereof. The backlight unit may be divided into an edge method in which the light source is disposed at one side and a direct method in which the light source is disposed below, according to the arrangement of the light source. The direct type backlight unit may include a fluorescent lamp for generating light, a reflector for reflecting the generated light in a direction in which the liquid crystal panel is located, and a light diffusion plate. The light diffusion plate serves to induce light uniformly incident on the entire liquid crystal panel by scattering light generated from a fluorescent lamp or an LED lamp as a light source.

The light diffusion plate is composed of a transparent thermoplastic resin, and has a light transmission effect for transmitting light of direct sunlight or a fluorescent lamp with high transmittance, and a light diffusion effect for diffusing light and hiding power such that the light source is not visible to the naked eye. Diffusing agents can be added to the resin. The light diffusing agent may be added as an inorganic material or an organic material having a resin and a refractive index difference of about 0.02 to 0.13. On the other hand, in order to suppress the color deformation of the diffusion plate due to the ultraviolet light emitted from the light source, an ultraviolet stabilizer may be further added, and in some cases, a lubricant or an antioxidant may be further added.

Although the possibility of adding various compounds as an UV stabilizer has been suggested, it is designed and added to absorb the entire wavelength range of 200 nm to 400 nm, which is the wavelength of ultraviolet rays generated from an actual light source. Accordingly, an ultraviolet stabilizer may be added in excess to the light diffusion plate resin. In addition, while the absorption may be excessively performed in the wavelength band where absorption is unnecessary depending on the UV stabilizer, the ultraviolet absorption efficiency may be low in the wavelength band to be substantially absorbed. Therefore, development of a method of improving the light resistance of the light diffusion plate by adding an effective ultraviolet stabilizer is required.

An object of the present invention is to provide a light diffusion plate capable of relatively lightly absorbing a weak wavelength band of a transparent resin forming a light diffusion plate for a backlight unit of a liquid crystal display device, thereby improving light resistance to ultraviolet rays.

Consistency of the present invention, polycarbonate resin; A benzotriazole-based first ultraviolet stabilizer that is included in an amount of 0.05 to 1.00 parts by weight based on 100 parts by weight of the polycarbonate resin, and absorbs ultraviolet rays in the 280 nm to 300 nm wavelength band more predominantly than other wavelength bands; And a hydroxyphenyl triazine-based second ultraviolet stabilizer, which is included in an amount of 0.05 to 1.00 parts by weight based on 100 parts by weight of the polycarbonate resin, and absorbs ultraviolet rays in a wavelength range of 300 nm to 320 nm more predominantly than other wavelength bands. To present.

The first ultraviolet stabilizer may include a benzotriazole compound of Formula 1 having a molar weight of 655 g / mol to 670 g / mol.

Formula 1

The second ultraviolet stabilizer may include a hydroxyphenyl triazine compound of Formula 2 having a molar weight of 420 g / mol to 430 g / mol.

Formula 2

Another aspect of the present invention, the first polycarbonate resin, benzotriazole-based agent is contained 0.05 to 1.00 parts by weight based on 100 parts by weight of the first polycarbonate resin to absorb ultraviolet rays in the 280nm to 300nm wavelength band than other wavelength bands A first ultraviolet stabilizer, and a hydroxyphenyl triazine-based second ultraviolet stabilizer which is included in an amount of 0.05 to 1.00 parts by weight based on 100 parts by weight of the first polycarbonate resin and absorbs ultraviolet rays in the 300 nm to 320 nm wavelength band more predominantly than other wavelength bands. 1 base layer of the resin composition; And a skin layer of a second resin composition including a second polycarbonate resin on the base layer.

According to an embodiment of the present invention, the transparent resin constituting the light diffusing plate for the backlight unit of the liquid crystal display device is identified in the weak wavelength band, and by applying an ultraviolet stabilizer showing a relatively superior absorption ability to the weak wavelength band, It is possible to implement a light diffusion plate that can improve the light resistance to.

Embodiments of the present invention apply a polycarbonate (PC: PolyCarbonate) resin as a transparent resin constituting the light diffusion plate for the backlight unit of the liquid crystal display device, and experimentally confirm that the ultraviolet wavelength band of the PC resin is weak 280nm to 310nm wavelength band. In the ultraviolet region of the wavelength range of 280nm to 310nm, the PC resin is photolyzed to generate radicals, and yellowing species are easily attached to the radicals by yellowing, thereby causing yellowing of the PC resin. .

The UV stabilizer effective in light absorption is applied to the wavelength band of 280nm to 310nm, which is a weak wavelength of PC resin. For example, a combination of a benzotriazole-based UV stabilizer and a hydroxyphenyl triazine-based UV stabilizer is applied to absorb relatively predominantly in the 280 nm to 320 nm wavelength band, that is, the UV-B wavelength band. The PC resin can selectively absorb the 280nm to 310nm wavelength band, which is a weak ultraviolet wavelength band, thereby reducing the use of an ultraviolet stabilizer of an unnecessary component exhibiting superior absorption in other wavelength bands.

1 is a view illustrating a light diffusion plate of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the light diffusion plate 100 according to the embodiment of the present invention may be configured in a two-layer structure including a skin layer 120 on a base layer 110. All. In the light diffusion plate 100, the base layer 110 and the skin layer 120 may be coextruded using a coextruder. In this case, the light diffusion pattern 121, such as a lenticular shape, an embossing shape, a prism shape, or the like may be formed on the surface of the skin layer 120 by pattern transfer using a forming roller after coextrusion. . That is, the skin layer 120 may have a flat surface or may have various types of patterns on the surface for light diffusion. The light diffuser plate 110 may be molded by injection molding. In this case, the surface of the base layer 110 may be molded into a flat surface or may have an elliptic lenticular shape, an embossing shape, a prism shape, or the like pattern.

First resin composition

The first resin composition constituting the base layer (110 of FIG. 1) is a high transparency polycarbonate (PC) resin is applied, wherein the PC resin has a softening point Tg (glass transition temperature) of about 145 ℃ to 155 ℃ level . The UV-vulnerable wavelength band of this PC resin itself is confirmed to be 280 nm to 310 nm. The PC resin may be a PC resin having a melt index (MI) of 10 g / min to 30 g / 10 min at 300 ° C. and 2.5 kg load conditions. In PC resin, double bonds of carbon and oxygen of carbonate group are easily decomposed by ultraviolet rays to form radicals, and chromophores are easily attached and cause yellowing. This can lead to coloring of the product.

The photooxidation mechanism of the polycarbonate can be described as in Scheme 1 below.

Considering the photocatalytic reaction mechanism of polycarbonate, it can be damaged by ultraviolet light emitted from a cold cathode fluorescent lamp (CCFL) used as a light source. This adversely affects the reliability of the product, so use a UV stabilizer that can effectively absorb the ultraviolet radiation emitted by CCFL. The ultraviolet wavelength band emitted from CCFL is widely distributed in the range of 300 to 360 nm, and shows a dominant peak in the vicinity of 313 nm in the UV-B region (280 nm to 315 nm wavelength band). Accordingly, in order to suppress denaturation of the polycarbonate resin, a UV stabilizer that selectively absorbs 280 nm to 320 nm including 313 nm and has a relatively strong absorption band is applied.

In order to suppress color change to a PC resin, the heterogeneous ultraviolet stabilizer combination containing a benzo triazole ultraviolet stabilizer and the hydroxyphenyl triazine ultraviolet stabilizer is added. The benzotriazole UV stabilizer and the hydroxyphenyl triazine UV stabilizer are experimentally identified as UV stabilizers that can effectively absorb the wavelength range of 280 nm to 320 nm while effectively meeting the required whiteness of the light diffusion plate (100 in FIG. 1). .

The benzotriazole-based UV stabilizer is a compound having a molar weight (Mw) of 655 to 670 g / mol, and effectively absorbs ultraviolet rays by a benzene ring adjacent to an N-N-N bond. Although the benzotriazole-based compound may be represented in various forms, it is confirmed that the benzotriazole compound represented by Formula 1 exhibits a wavelength absorption of about 50% in the wavelength range of 300 nm to 320 nm. As such benzotriazole compound, LA-31 ultraviolet stabilizer by ADEKA Corporation can be exemplified.

As shown in FIG. 2, the benzotriazole UV stabilizer of Formula 1 exhibits a predominant absorption peak in the vicinity of the 310 nm wavelength band, and has an absorbance of 40% to 50% over the 300 nm to 320 nm wavelength band. Seems. FIG. 2 is a spectrum distribution showing the absorbance of benzotriazole compounds according to wavelength band. FIG. This is a result of showing a relatively good absorption in the wavelength range 300nm to 320nm compared to the compound for general UV stabilizer.

Hydroxyphenyl triazine UV stabilizers are effective compounds of the molar weight (Mw) of 420 ~ 430g / mol level, the benzene ring in which the C-N bond is continuous acts as a combiner to absorb and stabilize the ultraviolet light. Although various forms of compounds can be presented as hydroxyphenyl triazine-based UV stabilizers, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-hexylsiloxane as shown in Formula (2) It is confirmed that the cy-phenol (2- (4,6-Diphenyl-1,3,5-triazin-2-yl) -5-hexyloxy-phenol) shows an absorption of about 90% at 280 nm to 300 nm. . As such a hydroxyphenyl triazine compound, Ciba TINUVIN 1577 ultraviolet stabilizer can be exemplified.

As shown in FIG. 3, the triazine-based UV stabilizer of Formula 2 exhibits a maximum absorption peak near 280 nm and shows an absorbance of 60% to 90% for the 280 nm to 300 nm wavelength band. FIG. 3 is a spectrum distribution showing the absorbance of triazine compounds along the wavelength band. FIG. This is a result that shows a relatively good absorption in the wavelength range of 280nm to 300nm compared to the compound for general UV stabilizer.

In the embodiments of the present invention, a combination of two types of benzotriazole-based UV stabilizer and hydroxyphenyl triazine-based UV stabilizer is added to PC resin as UV stabilizer. Each UV stabilizer may be included by 0.05 to 1.00 parts by weight based on 100 parts by weight of the PC resin. By adding these heterogeneous UV stabilizers, the UV-B wavelength band is absorbed by approximately 70 to 80%, and the amount of UV stabilizer added can be relatively reduced, thereby effectively blocking the UV wavelength. In other words, rather than applying a UV stabilizer that absorbs uniformly over the entire UV wavelength range, effective UV blocking is possible by using a combination of UV stabilizers that selectively exhibit good absorption in a specific wavelength range.

In addition, based on 100 parts by weight (wt%) of the PC resin, a silicon-based light diffusing agent may be added in an amount of 0.1 to 1 parts by weight. In this case, the silicon light diffusing agent may have an average particle diameter of 2um to 4um. Silicon-based light diffusing agent is a particle having an average particle diameter of 2um having a refractive index that is 1/43 times that of a PC resin. In addition, an inorganic or organic material having a refractive index difference of about 0.02 to 0.13 from a PC resin may be used as the light diffusing agent, and as the inorganic fine particles, calcium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, silica, glass, talc, mica, White carbon, magnesium oxide, or zinc oxide may be used, and as the organic fine particles, teflon series, acrylic series, or styrene series may be used.

Meanwhile, a lubricant or an antioxidant may be further added to the first resin composition. The antioxidant may be added in an amount of 0.01 to 1 parts by weight, preferably 0.05 to 0.3 parts by weight, based on 100 parts by weight of the PC resin. These antioxidants Phosphite-based antioxidants may be applied. The phosphite-based antioxidant may be applied to PEP-36 by Adeka.

In the presence of oxygen, the PC resin undergoes a photo-oxidation reaction, in which -OH groups are attached to radicals generated by breaking of double bonding, which can be confirmed by FT IR (ATR) spectral analysis. As the exposure time increases, the transmittance decreases at 3200 to 3600 cm ⁻¹ , which is a range indicated by the -0H peak. This shows that the role of antioxidants that can inhibit the reaction of radicals and oxygen in the presence of oxygen is important.

The addition of the antioxidant may be added during molding of the light diffusing plate to improve the molding properties and the optical properties of the light diffusing plate. The addition of antioxidants may serve to more effectively prevent the high temperature fluid resin from bonding with oxygen and causing yellowing by oxidation in the extruder during extrusion of the high temperature process. In addition, the antioxidant itself can act as a thermal stabilizer, and by interacting with the UV-B wavelength band, it is possible to reduce the influence on the resin destruction by heat to suppress the destruction of the resin, thereby promoting the suppression of color coordinate change.

Second resin composition

In the second resin composition constituting the base layer (120 of FIG. 1), a high transparency polycarbonate (PC) resin may be applied as in the first resin composition. In this case, the PC resin may have a softening point Tg (glass transition temperature) of about 145 ° C to 155 ° C. The PC resin applied to the second resin composition may use a PC resin having a higher MI than that of the PC resin applied to the first resin composition. For example, a PC resin having a Melt Index (MI) of 55 g / min to 80 g / 10 min at 300 ° C. and 2.5 kg load conditions may be used.

The first resin composition and the second resin composition may be coextruded to produce a light diffusion plate 110 including a base layer 110 and a skin layer 120 as shown in FIG. 1. At this time, the UV stabilizers of the present invention have been confirmed experimentally at a temperature showing a decomposition loss of more than 5wt% at 380 to 420 ℃, ultraviolet rays that are decomposed and gasified by the resin temperature 250 ℃ to 290 ℃ set to the coextrusion temperature The content of stabilizer can be effectively reduced.

TGA analysis results of a temperature increase rate (° C / min) of 20 ° C. per minute showed an initial pyrolysis temperature of 425.84 ° C. for the Adeca LA-31, i. Pyrolysis temperature is shown. In addition, when it is maintained at 280 ° C. for about 30 minutes, gas generation shows a weight loss of 5.733 parts by Adeka's LA-31 and 10.64 parts by weight of Ciba's TINUVIN 1577. The results of this pyrolysis and gas generation demonstrate that the amount of UV stabilizer that is gasified and blown off at a process temperature of 250 ° C. to 290 ° C. in the light diffusion plate extrusion process.

Accordingly, the amount of the UV stabilizer substantially added can be added in a small amount of about 0.05 parts by weight to about 1.00 parts by weight, and the black spots and the spots caused by the excessive addition of the UV stabilizer can be suppressed. Accordingly, it is possible to suppress the generation of foreign matter on the light diffusion plate, and to improve the cleanliness in the extrusion process. Although a small amount of UV stabilizer is added as described above, the base layer 110 may absorb about 70% to 80% of the UV-B wavelength band, thereby realizing the effect of protecting the diffusion plate.

The present invention will be described in more detail with reference to specific examples, but these examples are provided to illustrate the present invention and are not intended to limit the protection scope of the present invention.

Polycarbonate Modification Evaluation

Table 1 is the result of measuring the color coordinate change amount of polycarbonate (PC) resin and polystyrene (PS) resin.

Time (hr) 0hrs 24hrs 48hrs 72hrs 144hrs Δx △ y Δx △ y Δx △ y Δx △ y Δx △ y PC 0.000 0.000 0.005 0.009 0.008 0.012 0.010 0.016 0.013 0.019 PS 0.000 0.000 0.004 0.006 0.006 0.010 0.011 0.017 0.020 0.027

Cheil Industries PC resin and Toyo PS resin were injected into a 3.2mm (thickness) × 10.0mm × 10.0mm size to prepare a specimen, and then the amount of change in color coordinates (△ x, △ y) was measured by exposure. The results as shown in Table 1 are obtained. The measuring method is carried out using an exposure machine UVB-313, according to ASTM G154-06. The wavelength range of the exposure machine is 280-320 nm and the maximum peak is 313 nm. The amount of exposure unit energy is 1.23 W / m 2 / nm and the internal temperature is maintained at 60 ° C. to confirm the difference in YI according to the exposure for a total amount of 96 hours every 24 hours. Data measurement is performed in the xyY mode by applying the transmission mode using the CM-3600D of Minolta, and the reference value of the color coordinate change is Δx, which is the difference between the color before exposure and the color during exposure by unit time, 0.006 or less, Δy is determined to be 0.009 or less. That is, when the amount of change is greater than or equal to, it may be determined that the defect is substantially caused by denaturation.

Considering the results in Table 1, it can be seen that the initial color coordinate change occurs relatively quickly on the PC. This demonstrates that the radical formation of PC resins affects chromophore attachment and yellows.

UV stabilizer addition evaluation

Table 2 shows comparative examples and examples of the first resin composition for the base layer.

Component (wt%) PC Hydrophenol benzotriazole Oxanyl
Ride system Benzotriazole
(300 ~ 320nm absorption) Hydroxyphenyl triazine (280-300 nm absorption) Maloxate Antioxidant Cheil Industries
PC Shiva TINUVIN P Shivasa
TINUVIN 312 Adeka
LA-31 Shivasa
TINUVIN 1577 Clariant
Hostavin
B-Cap Adecasa
PEP-36 Example 1 100 0.1 0.1 Example 2 100 0.3 0.3 Example 3 100 0.1 0.1 0.1 Example 4 100 0.1 0.1 0.1 Comparative Example 1 100 0.1 0.1

Example 1:

Using polycarbonate resin of Cheil Industries, LA-31 of ADEKA Co., Ltd., a benzotriazole-based UV stabilizer, was added as a UV stabilizer, and a hydroxyphenyl triazine-based UV stabilizer was used. 0.1 parts by weight (wt%) of TINUVIN 1577 manufactured by Ciba, Inc. was added to prepare a first resin composition. The first resin composition is injection molded in the same manner as in the method of polycapcarbonate modification evaluation to prepare specimens, and then the amount of color coordinate change is measured in the same manner.

Example 2:

0.3 parts by weight of UV stabilizers were added to prepare a first resin composition, except that the specimens were prepared in the same manner as in Example 1, and the amount of color coordinate change was measured.

Example 3:

A specimen was prepared in the same manner as in Example 1 except that 0.1 parts by weight of a malonate-based UV stabilizer was further added to the first resin composition of Example 1, and the amount of color coordinate change was measured. Maloxane UV light stabilizer is applied to Clariant's Hostavin B-CAP.

Example 4:

A specimen was prepared in the same manner as in Example 1 except that 0.1 parts by weight of a phosphite-based antioxidant was added to the first resin composition of Example 1, and the amount of color coordinate change was measured. Phospite-based antioxidant is applied to PEP-36 of Adeka (ADEKA).

Comparative Example 1:

A specimen was prepared in the same manner as in Example 1 except that 0.1 parts by weight of CIBA TINUVIN P and Ciba TINUVIN 312 were added as UV stabilizers to Cheil Industries PC resin, and the amount of color coordinate change was measured.

Table 3 shows the color coordinate changes of the comparative examples and examples of the first resin composition for the base layer.

time
(hr) 24hrs 48hrs 72hrs 96hrs Δx △ y Δx △ y Δx △ y Δx △ y Example 1 0.000 0.000 0.003 0.005 0.005 0.009 0.008 0.011 Example 2 0.000 0.000 0.002 0.004 0.004 0.006 0.006 0.009 Example 3 0.000 0.000 0.003 0.004 0.005 0.008 0.007 0.011 Example 4 0.000 0.000 0.003 0.004 0.005 0.007 0.007 0.010 Comparative Example 1 0.000 0.000 0.003 0.006 0.006 0.009 0.008 0.012

As shown in Table 3, when the benzotriazole-based UV stabilizer and the hydroxyphenyl triazine-based UV stabilizer are added together to the PC resin, the amount of color coordinate change can be more effectively suppressed. Substantially, as in Example 2, 0.3 parts by weight of a benzotriazole-based UV stabilizer and a hydroxyphenyl triazine-based UV stabilizer were added in an amount of 0.3 parts by weight. Δx, which is a range in which the amount of change is required, satisfies 0.006 or less and Δy satisfies 0.009 or less.

On the other hand, the addition of the antioxidant may have a change in the color coordinates compared to when the antioxidant is not added, but may be added during molding of the light diffusion plate to improve the molding characteristics and optical properties of the light diffusion plate. The addition of antioxidants prevents the hot flowable resin from bonding with oxygen and causing yellowing by oxidation in the extruder during extrusion of the high temperature process. In addition, the antioxidant itself acts as a heat stabilizer, and interacts with the UV-B wavelength band at the experimental temperature of 60 ℃, it can help to suppress the change in color coordinates by reducing the impact on resin destruction.

Considering the results of Table 3, the benzotriazole-based UV stabilizer and the hydroxyphenyl triazine-based UV stabilizer can effectively inhibit the denaturation of PC resin when added in an amount of 0.2 to 0.8 parts by weight as a whole. It may be added, more preferably in the range of from 0.1 parts by weight to 0.1 parts by weight. At this time, the ratio between each of the benzotriazole-based UV stabilizer and the hydroxyphenyl triazine-based UV stabilizer can be adjusted in the range of 1: 1 to 1: 0.1, but 1: 0.5 to 1 : More valid in the 1 range.

Thus, embodiments of the present invention, when constructing a diffusion plate of a two-layer structure in which the base layer and the upper skin layer is coextruded, a combination of heterogeneous UV stabilizers with high light absorption at the UV-B wavelength band in the base layer By adding, the polycarbonate resin can be protected by the UV wavelength band emitted from the backlight unit.

At this time, even a small amount of ultraviolet light stabilizer can selectively and effectively absorb a specific ultraviolet wavelength band in which the polycarbonate resin is weak. With the addition of the light diffusing agent, the decrease in the light resistance of the diffuser plate caused by the increased amount of light refracted / reflected can be suppressed by the UV stabilizer combination. Increasing the amount of ultraviolet light stabilizer can be suppressed in proportion to the amount of light diffusing agent, thereby reducing the amount of color coordinate change caused by the addition of an excessive amount of ultraviolet light stabilizer.

In addition, the UV stabilizer combination according to the embodiments of the present invention exhibits a weight loss of 5 wt% or more may be approximately 380 ° C. to 430 ° C. when the thermal decomposition reaches 5 wt% weight loss. Therefore, in the light diffusion plate extrusion process having a process temperature of 250 ° C to 290 ° C, it is possible to further reduce the loss of the ultraviolet stabilizer that is gasified and flies away. Accordingly, the substantial content of the UV stabilizer is reduced to reduce defects such as black spots and white spots, to reduce foreign matters in the light diffusion plate, and to improve process cleanliness.

Although the present invention has been described with reference to the embodiments, these are merely exemplary, and those skilled in the art will appreciate that various modifications and equivalent other embodiments are possible therefrom.

1 is a view illustrating a light diffusion plate of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is an absorption spectrum distribution of a benzotriazole ultraviolet stabilizer according to an embodiment of the present invention.

3 is an absorption spectrum distribution of a hydroxyphenyltriazine ultraviolet stabilizer according to an embodiment of the present invention.

Claims (8)

Polycarbonate resins; A benzotriazole-based first ultraviolet stabilizer that is included in an amount of 0.05 to 1.00 parts by weight based on 100 parts by weight of the polycarbonate resin, and absorbs ultraviolet rays in the 280 nm to 300 nm wavelength band more predominantly than other wavelength bands; And And a hydroxyphenyl triazine-based second ultraviolet stabilizer, which is included in an amount of 0.05 to 1.00 parts by weight based on 100 parts by weight of the polycarbonate resin and absorbs ultraviolet rays in a wavelength range of 300 nm to 320 nm more than other wavelength ranges. The method of claim 1, The first ultraviolet light stabilizer A light diffusion plate of a liquid crystal display device comprising a benzotriazole compound of formula 1 having a molar weight of 655g / mol to 670g / mol. Formula 1

The method of claim 1, The second ultraviolet stabilizer A light diffusion plate of a liquid crystal display device comprising a hydroxyphenyl triazine compound of formula 2 having a molar weight of 420g / mol to 430g / mol. Formula 2

The method of claim 1, The first ultraviolet light stabilizer The light diffusion plate of the liquid crystal display device containing 0.1 to 0.3 parts by weight based on 100 parts by weight of the polycarbonate resin. The method of claim 1, The second ultraviolet stabilizer The light diffusion plate of the liquid crystal display device containing 0.1 to 0.3 parts by weight based on 100 parts by weight of the polycarbonate resin. The method of claim 1, The light diffusion plate of the liquid crystal display device further comprising a silicic light diffusing agent having an average particle diameter of 2um to 4um contained in 0.1 to 1.0 parts by weight based on 100 parts by weight of the polycarbonate resin. The method of claim 1, The light diffusion plate of the liquid crystal display device further comprises a phosphite-based antioxidant is included 0.01 to 1.0 parts by weight based on 100 parts by weight of the polycarbonate resin. First polycarbonate resin, A benzotriazole-based first ultraviolet stabilizer that is contained 0.05 to 1.00 parts by weight based on 100 parts by weight of the first polycarbonate resin to absorb ultraviolet rays in the 280 nm to 300 nm wavelength band more predominantly than other wavelength bands, and Bay of the first resin composition comprising a hydroxyphenyl triazine-based second ultraviolet light stabilizer is contained in the 0.05 to 1.00 parts by weight based on 100 parts by weight of the first polycarbonate resin to absorb ultraviolet rays in the 300nm to 320nm wavelength band than other wavelength bands Base layer; And The light diffusion plate of the liquid crystal display device comprising a skin layer of the second resin composition comprising a second polycarbonate resin on the base layer.

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