TWI345081B - Light diffusion sheet for a display device - Google Patents

Description

File: TW3873F IX. Description of the Invention: [Technical Field] The present invention relates to a light diffusion sheet for a display device, and more particularly to a light expansion sheet for a liquid crystal display 3b dogs improve light resistance, luminous efficiency and light diffusivity. [Prior Art] A general & liquid crystal display (LCD) is one type of flat panel display. It utilizes an applied electric field to the liquid crystals in the two substrates and controls the intensity of the electric field to control the amount of light transmitted by the external light source through the substrate to display the image. The external light source is a backlight unit (BLU). Thus, a conventional liquid crystal display has a backlight unit disposed on a rear surface thereof. The conventional backlight unit is not an edge-lit backlight unit, and is a direct-lit backlight unit. Among them, the 'sidelight type backlight unit is a backlight unit used for a thin screen, such as a screen of a notebook type or a desktop type computer. The direct type backlight unit is used for a large-sized device such as a liquid crystal television (LCD TV). A conventional direct type backlight unit includes a light source for emitting vertical light to a panel of a liquid crystal display, and penetrating at least one of the reflection sheets and one of the light diffusion sheets. The light diffusing sheet is used to scatter the light emitted from the light source so that the light can be uniformly dispersed and spread over the panel of the liquid crystal display. The conventional light diffusing sheet comprises a light diffuser and a transparent thermoplastic film base layer, and the light diffusing agent is located on the film base layer, wherein the film base layer is, for example, methacrylic, styrene, Cycloolefin 1345081

File: TW3873F a resin such as a cycloolefin or a polycarbonate (P〇ly carb〇nate). However, for a backlight unit, for example, when used in a large-sized liquid crystal television, it is possible to provide sufficient brightness by increasing the light emitted from the light source. However, the increase in the amount of light causes the heat source generated by the backlight unit to be greatly increased, resulting in distortion of the light diffusing sheet. In particular, a transparent film base layer of a conventional light diffusing sheet formed of a conventional base resin, for example, a transparent film base layer formed of methacrylic acid and styrene resin, which is deformed by an excessive heat source generated by a light source of the backlight unit . Therefore, in the industry, it is indeed necessary to have a light diffusing film that can resist high heat sources, and the light diffusing film must also have sufficient optical properties and formability. SUMMARY OF THE INVENTION In view of the above, the present invention provides a light diffusing sheet to sufficiently overcome the aforementioned technical disadvantages. In a feature of an embodiment of the present invention, a light diffusing sheet for a display device is proposed, and the light diffusing sheet has strong light resistance. In accordance with an aspect of the present invention, in order to make the foregoing or other features and advantages of the present invention easier to understand, an optical diffuser for a display device is proposed. The light diffusing sheet comprises a base layer and at least one coating layer. The base layer comprises a substrate 桢f grease and a first light diffusing agent, and the base resin is a mixture of a methacrylate-stupid copolymer and a methyl methacrylate-styrene copolymer. The content of the coating layer is 0.2 ppwb-20 ppwb. The coating layer is located above the substrate layer, and the coating layer comprises a coated substrate tree 7 1345081.

File: TW3873F grease, a second light diffusing agent, an ultraviolet light absorber and an antistatic agent, coated with a base resin, a fluorenyl acrylate-styrene copolymer, and a second light diffusing agent having a content of 0.1 ppwb -30 ppwb, the content of the ultraviolet light absorber is 0.01 ppwb - 2 ppwb, and the content of the antistatic agent is 0.01 ppwb - 10 Oppwb. The thickness of the base layer is 100#m-10000/zm, and the thickness of the coating layer is 1〇 // m-1000 /z m.

The thiol acrylate-styrene copolymer of the base layer comprises a methacrylic acid acrylate monomer in an amount of from 2% to 20% by weight and a styrene monomer in an amount of from 80% to 98% by weight. The methyl methacrylate-styrene copolymer of the base layer comprises from 6% to 94% by weight of methyl methacrylate monomer and from 6% to 94% by weight of styrene monomer. The first light diffusing agent of the base layer comprises a siloxane composition having a content of 0.1 ppwb-lOppwb and an acrylic composition having a content of (Uppwb-lOppwb), wherein the composition is composed of a sulphuric acid The average diameter of the average diameter A l / zn ^ G / zm 'acrylic acid is 1 y m-20 / zm. The second light diffusing agent of the coating layer includes - the average diameter is i / / m ~ 5 〇 / / The composition of the proacetin ester, an average singularity J and 4 is a combination of a decane composition of lem~2()//rn or a composition of an acrylic vinegar and a oxoxane. .. including polydimethylsiloxane, polydiethylsiloxane, and _ ", a two-dimensional network of silicone resin One or more of them. 8 1345081

File: TW3873F Acrylic vinegar composition, which is methyl methacrylate, ethyl methacrylate, butyl methacrylate, fluorenyl methacrylate Cyclomethyl methacrylate, phenyl methacrylate, benzyl methacrylate, methyl acrylate, monoacrylic acid Ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, and benzyl acrylate One or more of them. The coating layer of the ultraviolet light absorber is used to absorb ultraviolet light having a wavelength of from 250 nm to 280 nm. The ultraviolet light absorber is one of benzophenone, benzotriazole, cyanoacrylate, and a nickel complex salt or A combination of multiples. The antistatic agent of the coating layer is a polyether imide amide, a polyether ester, a polyether ester amide, a polyalkylene glycol. (polyalkylene glycol), alkali metal dodecylbenzene sulfonate, a tertiary amine, a quaternary ammonium, a sodium chloride, and a calcining group A combination of one or more of the alkyl amines. The coating layer further includes blowing agents and plasticizers 9 1345081

File: TW3873F (plasticizers), antioxidants, thermal stabilizers, lubricants, flame retardants, fillers, release agents, color Dyes, pigments, anti-dropping agents, nucleating agents, light stabilizers or a set of coating layers comprising a relief pattern, embossing The pattern is an amorphous embossed pattern, and the surface of the embossed pattern has a thick chain of 〇, 1 /zm-20#m. The coating layer further includes a light stabilizer. The light diffusion sheet further includes two coating layers sandwiched between the two coating layers. In accordance with another aspect of the present invention, and in order to facilitate the understanding of the foregoing or other features and advantages of the present invention, a backlight unit is proposed. The backlight unit includes a light source, at least one reflective sheet, and a light diffusing sheet. The light diffusion sheet comprises a base layer comprising a base resin and a first light diffusing agent, and the base resin is a thiol acrylate-styrene copolymer and a methyl methacrylate-benzene. Mixture of ethylene copolymer 'The first light diffusing agent contains 0.2ppwb-20ppwb, and the coating layer is above the base layer'. The coating layer comprises a coated base resin, a second light diffusing agent and an ultraviolet light absorber. And an antistatic agent, the base resin is coated with a methyl methacrylate-styrene copolymer, the second light diffusing agent is 0.1 ppwb-30 ppwb, and the ultraviolet light absorbing agent is 0.01 Ppwb-2PPwb, antistatic The content of the agent is 〇〇〇lppwb_1〇ppwb. According to still another aspect of the present invention, the foregoing or other features and advantages of the present invention are more readily understood. A display device is proposed herein. This display 1345081

File: The TW3873F display device includes a display panel and a backlight unit. The backlight unit comprises a light source and a light diffusion sheet. The light diffusion sheet comprises a base layer and at least one coating layer. The base layer comprises a base resin and a first light diffusing agent, and the base resin is a methacrylate-styrene. a mixture of a copolymer and a methyl methacrylate-styrene copolymer, the content of the first light diffusing agent is 0.2 ppwb-20 ppwb, the coating layer is on the base layer, and the coating layer comprises a coating base resin, a first a light diffusing agent, an ultraviolet light absorber and an antistatic agent, coated with a base resin, a fluorenyl acrylate-styrene copolymer, and a second light diffusing agent having a content of 〇.lppwb-30ppwb, ultraviolet light absorption The content of the agent is 0.01 ppwb to 2 ppwb, and the content of the antistatic agent is 0.01 ppwb to 10 ppwb. Wherein, the display device is a liquid crystal display. In order to make the above-mentioned contents of the present invention more comprehensible, a preferred embodiment will be described below in conjunction with the accompanying drawings, and the following detailed description is given as follows: [Embodiment] Submitted on July 7, 2006 and 2006, respectively. Korean Patent Application No. 10-2006-0064065 and No. 10-2006-0122521 of December 5, the patent name of which is "Light Diffusion Sheet for LCD Back Light Unit" The entire contents of this application are incorporated herein by reference. The invention will be described in detail below with reference to the accompanying drawings, which are illustrated by the preferred embodiment of the invention. However, the present invention may be embodied in many different forms and the invention is not limited by the embodiments. Rather, the invention is fully and exhaustively disclosed in the preferred embodiment. 11 1345081

File: TW3873F In the following, the technical field of the present invention is fully conveyed to those skilled in the art. In order to clearly express the drawings, the dimensions of the laminates and regions are enlarged in the drawings. In the text, when a layer or element is referred to as being "on" another layer or substrate, it is meant that the layer or element is directly over the other layer or another substrate, or There are other intermediate layers. In addition, when a layer or element is referred to as being "under" another layer or another substrate, it is meant that the layer or element is directly beneath the other layer or another substrate, or Save • There are one or more intermediate layers. Furthermore, when it is mentioned that the laminate is "in the middle" of the two laminates, it means that the laminate is directly in the "middle" of the two laminates, or one or more intermediate layers are present. Also, the same elements are used in the same reference numerals. Referring to Figures 1 and 2, there is shown a light diffusing sheet according to a preferred embodiment of the present invention, wherein the light diffusing sheet is applied to a display device such as a liquid crystal display. The first and second figures will be described in more detail below. The light diffusing sheet 20 as shown in Fig. 1 comprises a base layer 200 and at least one coating layer 210, and the coating layer 210 is located above the base layer 200. When the light diffusing sheet 20 is applied to a display device (not shown), the base layer 200 of the light diffusing sheet 20 serves as a supporting substrate of the light diffusing sheet 20. The thickness of the base layer 200 can be about 100 to 10000/zm, i.e., the distance along the y-axis. The base layer 200 comprises a base resin of about 100 parts by weight and a light diffusing agent of about 0.2-20 parts by weight, and the light diffusing agent has an average diameter of about 1 # m-20 #m. In this regard, it should be noted that the weight component 12

File: TW3873F is based on the weight of the base resin of the base layer 200 or based on the weight of the coated base resin of the coating layer 210. Namely, the weight component in the base resin of 1 Å by weight, or "parts by weight per 100 parts by weight of the base resin". More specifically, for the weight component of the base layer 200, ''ppwb'' is based on the base resin of the base layer 200. For the weight component of the coating layer 210, ''ppwb'' is a coating layer. The coated base resin of 210 is used as a reference. This will be explained in more detail below. Furthermore, the base layer 200 comprises a base resin, a base resin, a methacrylate styrene (MS) copolymer and a methylmethacrylate styrene (MMS) copolymer. a mixture of things. MS and MMS are mixed by a suitable technique such as emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, and the like. The MS copolymer comprises from 1% to 20% by weight of the methacrylate monomer and from 80% to 98% by weight of the styrene monomer. Preferably, the MS copolymer comprises from 5% to 10% by weight of methacrylate monomer and from 90% to 95% by weight of styrene monomer. It is based on polystyrene and the average molecular weight of the ruthenium-ST copolymer is about 200,000 to 350,000. The MMS copolymer comprises from 6% to 94% by weight of the methacrylate monomer and from 6% to 94% by weight of the styrene monomer. 134,5081

File: TW3873F and preferably the 'MMS copolymer system comprises a ruthenium, ·, 20%-80% mercapto acrylate monomer and a weight ratio of 20% to 80% of stupid ethylene monomer . It is based on polystyrene, and the average molecular weight of the copolymer is about 7 〇, 〇〇〇~3〇〇, 〇〇〇. The light diffusing agent of the base 200 comprises a plurality of organic teacher particles. The organic particles are, for example, Weiyuan, fluorinated polymerization;

(撼〇_), acrylic acid and/or styrene. Inorganic teachants are, for example, carbon dioxide, barium sulfate, titanium dioxide, hydroxide, quartz dioxide, glass, talc, mica, and white carbon. 11), magnesium oxide and / or zinc oxide. There are: particles or inorganic particles dispersed in a mixture of base resins whose refractive index differs from that of the base resin by about 〇 〇 2 〇 13 . /, soil 1 In the present embodiment, the light diffusing agent comprises a composition of oxetane having a content of 0.1 ppwb-lOppwb and an acrylate composition having a content of 〇.lPPwb-10Ppwv. The average diameter of the composition of the helium group = l/zm-20/zm' of acrylic acid vinegar is . By way of example, the rhodium hydride composition may be a crosslinked Weixuan resin having spherical crosslinked particles. Cross-linked money-burning resin system / included in the /BZL is the singular oxy-resin (Sjlic〇ne generation), a poly-pyro-alkylene oxide resin (P〇lydialkylsil〇xane resin) Road structure of stone oxide resin' and other materials. The epoxy resin which is solid at room temperature is, for example, a silicone rubber having a low degree of crosslinking and a high fluidity (silicone = bber) and an oxygen wax having a high degree of crosslinking and high hardness. The polydialkyl decane resin is, for example, p-polydimethylsilxane and p〇lydiethy lsil〇xane. With three-dimensional network junction 1345081

File: TW3873F is a epoxixy terminated moiety-containing siioxane. Without exceeding the theoretical scope, such as the use of cross-linked alkane resin, it will give the light diffusing agent excellent wettability, so that the light diffusing agent can significantly reduce the yellowing caused by long-term illumination of the light source. (yellowing). The decane composition has a lower refractive index than the other organic crosslinking compounds. More specifically, the refractive index of the helium alkane composition is about 40.40-1.43. Therefore, in the range not exceeding the theory, compared with other organic cross-linking resins, even if only a small amount of the composition is used, the light diffusing sheet 20 can be given sufficient light diffusivity and light transmittance. By exemplifying the acrylate composition, the acrylate composition in the light diffusing agent of the base layer 2 includes an acrylic monofunctional monomer (such as an alkyl acrylate), a decyl acrylate, and the like. And a combination of the foregoing respective acrylate compositions. The alkyl acrylate is, for example, ethyl acrylate, propyl acrylate, butyl acetoacetate, cyclohexyl propyl acrylate, phenyl propyl acrylate, benzyl urethane. The alkyl methacrylate is, for example, ethyl methacrylate, methyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, and methyl methacrylate. Further, the acrylate composition may be a spherical crosslinked particle, and the acrylate composition has a refractive index of about 1.46-1.56. In this regard, the refractive index of the acrylate composition varies depending on the content of the methyl acrylate and the MS copolymer. That is, if the content of the phenyl group or the halogen group is increased, the refractive index of the acrylate composition is increased. The base layer 200 of the light diffusing sheet 20 further includes an impact resistance modifier. Anti-impact agent to strengthen the base layer 2 〇〇 15 15 81

File: TW3873F, for example, can provide the base layer 200 with high impact resistance and high flexibility. The impactor comprises an elastomer such as acrylate rubber, mercapto propylene rubber rubber, polybutyl acrylate rubber, and others. As shown in Fig. 1, at least one coating layer 210 of the light diffusion sheet 20 is formed over the base layer 200 and has a thickness of about 10/zm to 1,000/zm. The coating layer 210 of the light diffusing sheet 20 comprises a coated base resin of about 100 parts by weight, a light diffusing agent having a content of about 0.1 ppwb to 30 ppwb, and an ultraviolet light absorbing agent (UV) having a content of about 0.01 ppwb to 2 ppwb. Lu absorber), an antistatic agent having a content of about 〇〇.〇〇lppwb-10ppwb. The average diameter of the light diffusing agent is about lym-50 βπι. The coating base resin of the coating layer 210 is different from the base resin of the base layer 200. Specifically, the coated base resin of the coating layer 210 comprises an MMS copolymer. The MMS copolymer of the coating base 210 coated with the base resin is substantially similar to the MMS copolymer of the base resin of the base layer 200, for example, the MMS copolymer system comprises a 6%-94% by weight of mercaptopropionic acid. The ester monomer and one part by weight are ό%·94% of styrene monomer. The light diffusing agent of the coating layer 21 comprises an acrylic vinegar composition, a monoxanthene composition or a combination of an acrylate composition and a decane composition. In this embodiment, the combination of the acrylate composition and/or the siloxane composition of the light diffusing agent of the coating layer 210 is substantially the same as the acrylate composition and/or the decane composition of the base layer 2 described above. Therefore, the detailed components thereof will not be described. However, the average diameter of the acrylic acid vinegar composition of the coating layer 210 is different from the average diameter of the acrylic acid composition of the base layer 200, but the refractive index remains the same. Not exceeding 16 1345081

File: TW3873F In the theoretical scope, the light diffusing agent of the coating layer 210 can control the brightness and gloss of the surface of the coating layer 210. For example, in the case of one of the coating layers 21, the shape of the surface, from the surface properties of the surface of the irregular shape, the light transmittance and the light diffusivity can be reduced, or the light transmittance and light can be prevented. The diffusivity is reduced. The ultraviolet light absorber of the coating layer 210 shields the ultraviolet light emitted from the light source to protect the light diffusion sheet 20. The ultraviolet light absorber may be any material capable of absorbing light having a wavelength of from 250 nm to 280 nm. For example, the ultraviolet light absorber may be benzophenone, benz〇triaz〇ie, cyanoacrylate, shuiyang. A combination of one or more of salicylate and a nickel complex salt. The ultraviolet light absorber may be added with a light stabilizer to reduce its free radical, thereby improving the durability of the entire coated base resin. The light stabilizer is any material capable of reducing any composition drop of the light diffusion sheet 20. For example, the antistatic agent of the hindered amine coating layer 210 can reduce the amount of the antistatic agent in the coating layer 210. Space charge. In particular, the MMS copolymer has a relatively high and significant resistance, which means that static electricity is easily generated on the surface of the MMS copolymer, so that dust accumulates and adsorbs on the surface of the MMS copolymer. However, this dust lowers the surface properties of the light-diffusing sheet 20, causing the light-emitting efficiency of the light-diffusing sheet 2 to drop and cause a situation of lamp discoloration. Thus, the antistatic agent of the coating layer 210 serves to reduce the static electricity on the surface thereof, thereby reducing the amount of dust on the surface thereof. Antistatic agent includes a polyether thioimino compound 17 1345081 *

File: TW3873F, a polyether ester, a polyether ester amino compound, a poly-dishylene glycol, a bis- thiosulfanic acid metal test, a tertiary amine compound, a quarterly compound, sodium chloride and A combination of one or more of the monoalkylamine compounds. The light diffusing sheet 20 further includes one or more additives. The additives include a foaming agent, a plasticizer, an antioxidant, a heat stabilizer, a lubricant, a flame retardant, a filler, a relaxant, a colorant, a dye, an anti-separator, a nucleating agent, or a combination of the foregoing various additives. For example, the use of a foaming agent in the light diffusing sheet 20 can reduce the yellowing phenomenon of the light diffusing sheet 20 due to resin cracking. The coating layer 210 has at least one irregularly shaped surface. For example, the coating layer has an amorphous embssing pattern 211 on its surface such that the transmitted light from the light source to the LCD panel can be scattered, diffused or concentrated via the light diffusing sheet 20. . In particular, when light penetrates from the pores of the amorphous embossed pattern 211 of the coating layer 210, the transmitted light diffuses, for example, in several directions, thereby enhancing the light penetration rate and light of the light diffusion sheet 20. Diffusion rate, and can improve the overall luminosity of the LCD. The surface roughness of the amorphous embossed pattern 211 of the coating layer 210 is 〇.1 by m_2〇', which is the average vertical height difference of a plurality of irregularities of the surface of the coating layer 210. The formation of the irregularly shaped surface of the coating layer 210 is, for example, by press processing, uv resin coating and processing, and contact processing via a polishing. Roll) and other methods. For example, the polishing roll forms a plurality of irregularities on the surface of the coating layer 210.

File: The TW3873F area, which makes the uniform scattered light emitted by the light source to the LCD (such as bright-line uniform scattered light) dim. The shape of the irregular shaped surface is, for example, dependent on the distance between the light sources, the distance between the light diffusing sheet and the light source, the brightness of the light source, and other conditions. Since the coating layer 210 is applied to the base layer 200, the amorphous embossed pattern 211 of the coating layer 210 is disposed on a surface different from the base layer 200. The base layer 200 and the coating layer 210 are bonded to each other by an appropriate method, such as injection molding, extrusion molding, vacuum molding, thermal-press molding, and the like. Coextrusion molding, film deposition, solvent adhesion, surface coating, lamination, and others. The composition of the light diffusing sheet 20 is mixed by a thermoplastic forming technique such as injection molding, extrusion molding, vacuum forming, hot press forming, co-embossing, and the like. In the case of multilayer-extrusion molding, for example, 'the base layer 200 and the coating layer 210 are separately subjected to composition mixing' and the respective mixtures are placed in a feed block die or a multi-tube. In a multi-manifold die. Further, a multi-layered board is formed by polishing rolling. This is a structure in which a plurality of layers are stacked along the y-axis. For example, a light-diffusing sheet 2 having a double-layered plate structure can be formed. According to another embodiment of the present invention, a light diffusing sheet 21 has a plurality of coating layers 210. The light diffusion sheet 21 is the same as the light diffusion sheet 20 except that it has a plurality of coating layers 210. For example, as shown in Fig. 2, the coating layer 210 is laminated on the base layer 2 13 1345081

File: TW3873F surface. In other words, the base layer 200 is located in at least two of the coating layers 21〇. Further, other forms of the base layer 200 and the coating layer 210 are also within the scope of the present invention.

According to an embodiment of the present invention, in the base layer 200, the base resin mixture of MS and MMS can improve the heat resistance, light resistance, and optical properties of the base layer 200. The spherical ortho-oxygen composition and/or the acrylate composition of the light diffusing agent can impart excellent light diffusivity and light transmittance to the underlying layer 200.

Further, if an organic light diffusing agent is used instead of a conventional inorganic light diffusing agent, the uniformity of light dispersion can be increased. Moreover, the use of organic light diffusing agents can also reduce the wear and tear of production equipment and reduce the adsorption of particles. Similarly, the composition of the coating layer 21 according to the embodiment of the present invention can greatly reduce the yellowing caused by long-term irradiation of light and/or heat and the amount of money adsorbed by electricity. Anti-static (4) and light-setting agents can be added to the coating layer 2H) to reduce production costs. Therefore, if the light diffusing film of the invention example is used, the display device can be improved in display characteristics, and at the same time, the production cost can be lowered. A careful understanding of the present invention will be made easier by the accompanying examples. However, this example is not intended to limit the scope of the invention. EXAMPLES Example 1: Fabrication of the base layer: Ester-::based acrylic vinegar-stupid ethylene (MS) copolymer and methyl ester. Add mrrr cut into _ ® basal tree of silk] '3 *,,, ppw stone oxime tree particles and content is 2ppwb 20 134.5081

File: TW3873F acrylate crosslinked particles to a base resin to form a component of the base layer. Wherein the average diameter of the 'oxygenated resin particles was 2/zm (available from GE Toshiba Silicone Co. Ltd.). The average diameter of the acrylate crosslinked particles was 8/zm (purchased from Sekisui Chemical Co., Ltd.). Fabrication of a cloth layer: 100 parts by weight of a coated base resin was formed from a methacrylate-styrene (MS) copolymer, and an acrylate crosslinked particle having a content of 1 〇 ppwb was added: an antistatic agent having a content of 1 ppwb, The content is from 1 ppwb 2 light stabilizer to the coating base resin to constitute a composition of the coating layer, wherein the average diameter of the parent granules of the acetoacetate is 20/zm (purchased from Sekisui chemical Co Ltd.). Production of multi-layer light diffusing sheet: The composition of the base layer and the composition of the coating layer are respectively injected into a die-cutting machine (her Qin), and the composition of the base layer and the composition of the coating layer are released after refining and grinding. - Feeding the mask, forming a multilayer light diffuser. The base layer light diffusion sheet has a base layer sandwiched between three laminated layers of the two coating layers. Thereafter, the thickness of each of the coating layers was measured, and the thickness of the substrate layer was measured to be 1,80 〇em. Example Control Group 1: A multilayer light diffusing sheet was produced according to the procedure of Example 1, except that the polystyrene (PS) tree was used as the coating base resin, and the rest and examples! The procedure is the same. Among them, the stupid job is to say "f ps Japan Coi*p." Example control group 2 : 21 1345081 ·

File: TW3873F A multilayer light-diffusing sheet was produced according to the procedure of Example 1, except that the polymethylmethacrylate (PMMA) resin was used as the base resin, and the procedure of the example control group 1 was the same. Among them, polymethyl methacrylate resin was purchased from "Mitsubishi Rayon Corp.". Example Control Group 3: A multilayer light-diffusing sheet was produced according to the procedure of Example 1, except that the procedure of Example Control 1 was the same except that polystyrene (PS) resin was used as the base resin. Among them, polystyrene resin was purchased from "PS Japan Coirp." The composition of each of the base layers and the composition of each coating layer of Example 1 and Example Control Groups 1-3 are summarized in Table 1 below. Table 1 Sample composition Example 1 Example control group 1 Example control group 2 Example control group 3 Base layer base resin MS/MMS MS/MMS PMMA PS Silicone resin light diffusing agent (ppwb) 2 2 2 2 Acrylate composition (ppwb 2 2 2 2 Coating layer coating base resin MS PS PS PS Acrylate composition (ppwb) 10 10 10 10 Antistatic agent (ppwb) 1 1 1 1 Light stabilizer (ppwb) 1 1 1 1 Evaluation examples will be given below 1 and the sag and optical values of each of the multilayer light diffusing sheets formed by the example control group 丨3. In each test, each of the multilayer light-diffusing sheets was prepared into a test piece having a size of 50 mm X 30 mm X 2 mm. And one side of each test piece is fixed. 22 1345081 *

File: The TW3873F sag test is as follows. The distance between each test piece relative to the reference point, that is, the height of the test piece to the ground, is measured. Place the test piece in a heating box and set the temperature and time to degrees Celsius and 1 hour. Then, the distance of each test piece relative to the aforementioned reference point, i.e., the sag (in millimeters), is measured again. The difference between the two measured distances is the distance at which the test piece hangs vertically due to the application of the heat source, which is recorded as the sag value. This sag value is an important data for the thermal resistance of the polymer. The method of optical property evaluation is as follows. Each test piece was irradiated with ultraviolet light from an ATLAS-UVCON radiator, and the set temperature and time were set at 60 degrees Celsius and 72 hours to evaluate the change of the yellow index (YI) of each test piece. This is a measure of the ΔΥΙ value of each test piece before and after irradiation with ultraviolet radiation according to the white color coordinates of the ASTM D1925 procedure. When the value of Δγι is smaller, it means that the light resistance is greater. The light transmittance and light scattering rate of each test piece were evaluated by a hazemeter. Each test piece was adhered to a 32-inch backlight unit' and the luminous efficiency of the backlight unit was measured by BM-7 luminosity. Among them, the haze meter NDH 5000W® (purchased from Nippon Denshoku Industries Co., Ltd.) ° The test results of the sag and optical properties are shown in Table 2-3. Table 2 Bend test results Example 1 Example control group 1 Example control group 2 Example control group 3 Results Ί Η Droop (mm) 1 10 6 13 or more 23 1345081

File: TW3873F As shown in Table 2, the resin of Example 1 (i.e., the base resin including the MS and MMS mixture) showed the best sag result, i.e., the sag value was .1 mm. In other words, the test piece of Example 1 had the smallest amount of change for the application of the heat source, and thus it had the most excellent heat resistance. Table 3 Optical test results Example 1 Example control group 1 Example control group 2 Example control group 3 Light resistance (ΔΥΙ) 8 11 5 15 Light transmittance (%) 51.1 52.0 62.3 53.2 Light scattering (%) 93.1 93.0 92.9 93.1 Luminous efficiency (cd/m2) 11,120 11,110 11,141 11,124 As shown in Table 3, the resin of Example 1 (i.e., the base resin including MS and MMS mixture) was compared with the example control group 1-3, and Example 1 showed the most Excellent UV light resistance, and its light transmittance, light diffusivity and luminous efficiency are still substantially the same as in the example control group 1-3. As shown in Figs. 4A and 4B, a light diffusing film according to an embodiment of the present invention is applied to a display device. More specifically, as shown in FIGS. 3A and 3B, the backlight units 40 and 41 of the liquid crystal display (not shown) respectively include at least one light source 100, a reflection sheet 110, and a light diffusion sheet 20 and 21. Here, in FIGS. 4A and 4B, the backlight units 40 and 41 are applied to the liquid crystal displays 400 and 410, respectively. The backlight unit using the light-diffusing sheet of the embodiment of the present invention can obtain improved light transmittance and light diffusivity by the amorphous embossed pattern on the light-diffusing sheet, thereby enhancing the brightness. In addition, the use of the invention of the real 24 1345081 « .

File: TW3873F The backlight unit of the light diffusing film of the example is excellent in light resistance and wettability by a mixture of MS/MMS resin and its multilayer structure. Finally, the backlight unit using the light diffusing sheet of the embodiment of the present invention can have relatively low wear and damage of the production equipment as compared with the conventional backlight unit. In view of the above, the present invention has been disclosed in a preferred embodiment, and is not intended to limit the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

25 134.5081

File: TW3873F [Simple Description of the Drawing] Fig. 1 is a schematic view showing a light diffusing sheet according to a preferred embodiment of the present invention. Fig. 2 is a schematic view showing a light diffusing sheet according to another preferred embodiment of the present invention. Fig. 3A is a cross-sectional view showing a backlight unit according to the light diffusion sheet of Fig. 1 of the present invention. Fig. 3B is a cross-sectional view showing the back light unit according to the light diffusing sheet of Fig. 2 of the present invention. Fig. 4A is an exploded view showing a display device according to the light diffusing sheet of Fig. 1 of the present invention. Fig. 4B is an exploded view showing the display device in accordance with the light diffusing sheet of Fig. 2 of the present invention. [Description of main component symbols] 20, 21: Light diffusing film Stomach 40, 41: Backlight unit 100: Light source 110: Reflecting sheet 200: Base layer 210: Coating layer 211: Embossed pattern 400, 410: Liquid crystal display device 26

Claims (1)

1345081 * · 〆 File: TW3873F • v X. Patent Application Range: 1. A light diffusion sheet for a display device, the light diffusion sheet comprising: a substrate layer, the substrate layer comprising: a substrate a resin, the base resin is a mixture of a methacrylate styrene (ΜΑ-ST) copolymer and a methylmethacrylate styrene (MMA-ST) copolymer; a first light diffuser having a content by weight per 100 parts by weight of the base resin (ppwb) of 0.2 ppwb_20 ppwb; and at least A coating layer is disposed above the substrate layer, the coating layer comprising: a coating base resin, the coating base resin is a mercapto acrylate-styrene copolymer; a second light diffusing agent, the second The content of the light diffusing agent is 0.1 ppwb based on the weight of the coating base resin (parts by weight pei·100 parts by weight of the base coating resin, ppwb). -30 ppwb; an ultraviolet absorber (UV absorber) The content of the ultraviolet light absorber is 0.01 ppwb to 2 ppwb based on the weight of the coated base resin; and an antistatic agent 'antistatic agent' The content of the agent is based on the weight of the coated base resin of 27, 1345081. File: TW3873F O.OOlppwb-lOppwb ° 2. The light diffusing sheet of the above-mentioned claim, wherein the methyl layer of the base layer The propylene succinyl ester-styrene copolymer comprises from 1% to 20% by weight of a weight percent. The methacrylate monomer and a styrene monomer in an amount of 80% to 98% by weight. 3. The light diffusing sheet of claim 2, wherein the methyl methacrylate styrene copolymer of the base layer comprises from 6% to 94% by weight of decyl methacrylate monomer. And a percentage by weight of 6% to 94% of styrene monomer. 4. The light diffusing sheet according to claim 1, wherein the first light diffusing agent comprises a siloxane composition having a content of 〇.lppwb-10ppwb and an acrylate having a content of 〇lppwb_10ppwb. An (acrylic) composition in which the average diameter of the composition of the decane is // m, and the average diameter of the acrylate composition is . The second light diffusing agent of the coating layer comprises a light diffusing sheet having an average diameter of I" m^5Q 5, wherein the rolling grade is composed of acrylic vinegar and an average diameter is 1 #m~20 // The combination of the composition of the acrylate or the composition of the oxylate. 6. The light diffusing sheet of claim 5, wherein the second light diffusing agent of the coating layer comprises the siloxane composition, which is a polydimethyl siloxane, a polydimethyl siloxane. A combination of one or more of polydiethylsiloxane and a silicone resin having a three-dimensional network structure.曰 其中 7 7 7 7 7 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 Methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, methacrylic acid benzoate (phenyl methacrylate), benzyl methacrylate, methyl acrylate, ethyl acrylate, butyl acetonate A combination of one or more of butyl acrylate), cyclohexyl acrylate, phenyl acrylate, and benzyl acrylate. 8. The light diffusing sheet of claim 1, wherein the ultraviolet light absorber is for absorbing ultraviolet light having a wavelength of from 250 nm to 280 nm. 9. The light diffusing sheet of claim 1, wherein the ultraviolet light absorber is benzophenone, benzotriazole, cyanoacrylate, And a combination of one or more of a nickel complex salt. 10. The light diffusing sheet of claim 1, wherein the antistatic agent is a polyether imide amide, a polyether ester, a polyester ester Polyether ester amide, polyalkylene glycol, alcohol metal dodecylbenzene sulfonate, tertiary amine, one season compound A combination of one or more of quaternary ammonium), sodium 29 1345081 File: TW3873F chloride, and ykyi amine. The light-diffusing sheet of claim 1, wherein the thickness of the base layer is 12. The light-diffusing sheet of claim 1, wherein the thickness of the coating layer is 10/im. -1000//m. 13. The light diffusing sheet of claim 1, wherein the coating layer comprises an embossed pattern. 14. The light diffusing sheet of claim 13, wherein the/the convex pattern is amorphous, and the surface roughness of the embossed pattern is 0.1 l/m_20/zm. 15. The light diffusing sheet of claim 1, wherein the coating layer further comprises a light stabilizer. 16. The light diffusing sheet of claim 1, wherein the light diffusing sheet comprises two coating layers. 17. The light diffusing sheet of claim 16, wherein the base layer is lost between the two coating layers. a backlight unit comprising: a light source; at least one reflective sheet; and a light diffusing sheet comprising a base layer and at least one coating layer, the base layer comprising a base resin and a first light a diffusing agent, a mixture of the base resin, a methacrylate styrene copolymer, and a methacrylic acid vinegar-styrene copolymer, the first light diffusing agent having a content of 30 134, 5081 File: TW3873F 0.2ppwb-20ppwb, the coating layer is located above the base layer, the coating layer comprises a coating base resin, a second light diffusing agent, an ultraviolet light absorber and an antistatic agent, and the coating base resin is The content of the second light diffusing agent is 〇.lppwb-30ppwb, the content of the ultraviolet light absorbing agent is 0.01ppwb-2ppwb, and the content of the antistatic agent is 0.011ppwb. -lOppwb. 19. A display device comprising: a display panel; and a backlight unit comprising: a light source and a light diffusing sheet, the light diffusing sheet comprising a base layer and at least one coating layer, the base layer comprising a base resin and a first light diffusing agent, the base resin being a mixture of a monomethacrylate-styrene copolymer and a methyl methacrylate-styrene copolymer, the first light diffusing agent having a content of 0.2 ppwb -20 ppwb, the coating layer is located on the base layer, the coating layer comprises a coating base resin, a second light diffusing agent, an ultraviolet light absorbing agent and an antistatic agent, and the coating base resin is a 曱The methacrylate-styrene copolymer, the content of the second light diffusing agent is 0.1 ppwb-30 ppwb, and the content of the ultraviolet light absorbing agent is 0.01 ppwb-2 ppwb. The content of the antistatic agent is 0.01 ppwb to lOppwb. . 20. The display device of claim 19, wherein the display device is a liquid crystal display. 31