TW201042294A - Process for producing light-diffusing element, light-diffusing element, and processes for producing polarizing plate with light-diffusing element and liquid-crystal display device - Google Patents

Abstract

A process for producing a light-diffusing element is provided by which a light-diffusing element having a high haze and high diffusing properties and reduced in backward scattering can be produced at low cost with high productivity. The process for producing a light-diffusing element comprises a step in which a matrix-forming material comprising a resin-ingredient precursor and an ultrafine-particle ingredient is brought into contact with fine light-diffusing particles, a step in which at least some of the precursor is infiltrated into an inner part of the fine light-diffusing particles, and a step in which the precursor that has infiltrated into the inner part of the fine light-diffusing particles and the precursor that has not infiltrated into the fine light-diffusing particles are simultaneously polymerized to form a matrix comprising the resin ingredient and the ultrafine-particle ingredient and simultaneously form a concentration gradation region in the vicinity of the inner side of the surface of the fine light-diffusing particles.

Description

[Technical Field] The present invention relates to a method of manufacturing a light diffusing element, a light diffusing element, and a polarizing plate with a light diffusing element and a method of manufacturing the liquid crystal display device. [Prior Art] Ο ❹ Light diffusing elements are widely used in lighting shades, rear projection televisions, surface light-emitting devices (such as liquid crystal display devices), and the like. In recent years, the use of light diffusing elements for improving the display quality of liquid crystal display devices and the like, and improving viewing angle characteristics are progressing. As the light-diffusing element, it has been proposed to disperse fine particles in a matrix such as a resin sheet (for example, see Patent Document). In such a light diffusing element, most of the incident light is scattered toward the front (the exit surface side), and a part of the light is scattered toward the rear (incidence surface side). The larger the refractive index difference between the fine particles and the matrix, the larger the diffusibility (for example, the haze value), but the other side, if the refractive index difference is large, the backscattering increases. If the backscattering is large, when the light diffusing element is used in a liquid crystal display device, the screen becomes white when external light is incident on the liquid crystal display device, so that it is difficult to display an image or an image having contrast. · As a method to solve the above problem, 'the concept of suppressing the reflection at the interface between the particle and the substrate' has been proposed to have a core-shell particle e-sheH partiele having a different refractive index between the core and the shell, or a refractive index from the center of the particle. A method in which a gradient-indexed particle such as a gradient index particle is dispersed in a resin (for example, see Patent Document 24), and "the particles are compared with ordinary particles. The manufacturing process is more complicated than 147072.doc 201042294, so the productivity is not sufficient and not practical. CITATION LIST Patent Literature Patent Literature 1: Japanese Patent No. 3071538 Patent Document 2: Japanese Patent Laid-Open Publication No. Hei No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to provide a high haze value which is low in cost and high in productivity, and has a strong A method of manufacturing a light diffusing element that diffuses and suppresses backscattering light diffusing elements. Means for Solving the Problem The method for producing a light diffusing element of the present invention comprises the steps of: contacting a matrix forming material comprising a resin component precursor and an ultrafine particle component with light diffusing fine particles; and infiltrating at least a portion of the precursor Up to the inside of the light diffusing fine particles; and simultaneously polymerizing the precursors that have penetrated into the light diffusing fine particles and the precursors before they penetrate into the light diffusing fine particles to form a matrix containing the resin component and the ultrafine particle component At the same time, a concentration modulation region is formed inside the vicinity of the surface of the light diffusing fine particles. In a preferred embodiment, the method of the present invention is characterized in that the precursor is infiltrated from the surface of the light diffusing fine particles to 10%/〇 or more and 95% or less of the average particle diameter of the light diffusing fine particles. The scope is up to now. In a preferred embodiment, the manufacturing method is such that the precursor of the resin component is in contact with the light diffusing fine particles for a longer period of time than when the particle diameter of the light diffusing fine particles is substantially maximized. In the preferred embodiment, the resin component is an ionizing radiation-curable tree. The above-described manufacturing method is to polymerize the resin component by irradiating ionizing radiation or a wire. According to another aspect of the invention, a light diffusing element is provided. The light diffusing element is obtained by the above method, and includes a substrate containing a resin component and an ultrafine particle component, and light diffusing fine particles dispersed in the matrix, and having the resin in the vicinity of the surface of the light diffusing fine particle. A concentration-modulating region formed by penetration of a component. According to still another aspect of the present invention, a method of manufacturing a polarizing plate with a light diffusing element is provided. In the method, a method of manufacturing the above light diffusing element is used. According to still another aspect of the present invention, a method of manufacturing a liquid crystal display device is provided. In the method, a method of manufacturing the above light diffusing element is used. Advantageous Effects of Invention According to the present invention, when a light diffusing element is produced by using a specific matrix resin component (on its shell) and a specific light diffusing fine particle in combination, the matrix resin component precursor can be infiltrated. To the inside of the light diffusing particles. The matrix can be formed by polymerizing the precursor of the matrix resin component and simultaneously forming a concentration-modulating region in the vicinity of the surface of the light-diffusing microparticle (ie, 'the matrix can be formed in one batch” Variable area). Thus, according to the present invention, it is not necessary to perform special processing or operation for forming a concentration-modulating region. Therefore, it is possible to manufacture a light-expanding elemental towel at low cost and high productivity and 'obtained by the manufacturing method of the present invention. The light diffusing element is formed with a concentration modulation region in the vicinity of the surface of the light diffusing fine particles. Therefore, the refractive index can be changed stepwise or substantially continuously in the vicinity of the interface between the light diffusing element and the substrate. Therefore, the reflection of the interface between the substrate and the light diffusing fine particles can be well controlled so that backscattering can be suppressed. Further, according to the present invention, the refractive index of the substrate can be easily adjusted by using an ultrafine particle component having a specific refractive index and a specific compatibility with respect to the resin component. In particular, according to the present invention, since the concentration of the ultrafine particle component in the matrix can be increased by infiltrating the resin component into the inside of the light diffusing fine particles, the refractive index difference between the matrix and the light diffusing fine particles can be easily increased. As a result, the haze element obtained by the production method of the present invention has a relatively high haze value, has strong diffusibility, and suppresses backscattering. [Embodiment] Hereinafter, the preferred embodiments of the present invention will be described with reference to the drawings, and the present invention is not limited to the specific embodiments.制造·Light diffusing element manufacturing method The method for producing a light diffusing element according to the present invention includes the following (4): contacting a matrix forming material containing a resin component precursor and an ultrafine particle component with light diffusing fine particles (step Α); At least a part of the precursor is allowed to permeate into the inside of the light diffusing fine particles (the step and (4) the precursor is polymerized to form a matrix containing the resin component and the ultrafine particle component, and simultaneously in the vicinity of the surface of the light diffusing fine particle A concentration modulation region is formed (set to step C). 147072.doc 201042294

Α-1·Step A In the step A, a coating liquid is prepared, which is obtained by dissolving or dispersing a matrix-forming material and a light-diffusing fine particle containing a resin component precursor and an ultrafine particle component. A solution made from a volatile solvent. Typically, the coating liquid is a dispersion in which an ultrafine particle component and light diffusing fine particles are dispersed in a precursor and a volatile solvent. As a method of dispersing the ultrafine particle component and the light diffusing fine particles, any appropriate method (e.g., ultrasonic treatment) can be employed. In the coating liquid, the light diffusing fine particles are in contact with the resin component precursor. A-1-1. Resin component The above-mentioned resin component may contain any appropriate material as long as the concentration-modulating region can be favorably formed. The refractive index of the resin component preferably satisfies the relationship of the following formula (1): 〇 < I Πρ-ΠΑ | · · (1). In the formula (1), 'ηΑ represents the refractive index of the resin component of the matrix, and ～ represents the refractive index of the optically dilated particles. I ηΡ-ηΑ I should be 〇.〇1~〇"〇, more preferably 〇_〇1~0.06, especially preferably 0.02~〇.06. If 丨ηρ·ηΑ丨 does not reach 〇 〇1, there is a case where the above-described concentration modulation region is not formed. If 丨ηΡ-ηΑ丨 exceeds 〇·1〇 ', there is an increase in backscattering. The resin component preferably contains a compound which is homologous to the light diffusing fine particles. More preferably, the resin component contains a compound having high compatibility with a compound of the same type as the light diffusing fine particles. Thereby, the resin component is a material which is the same as the light diffusing fine particles, and the precursor (monomer) can penetrate into the inside of the light diffusing fine particles. The precursor (monomer) is polymerized by a polymerization step described later. 147072.doc 201042294 As a result, ... the resin component can be utilized for light diffusibility, and the topography is __

In the present invention, the resin component preferably contains an organic compound, and more preferably contains an ionizing radiation curable resin. The coating film of the ionizing radiation curable resin is excellent in hardness. Examples of the ionizing radiation include ultraviolet rays, visible light, infrared rays, and electron beams. Ultraviolet rays are preferred, and therefore, the resin component is particularly preferably an ultraviolet curable resin. Examples of the ultraviolet curable resin include radical polymerizable monomers or oligomers such as acrylonitrile sulphate (epoxy acrylate, polyester acrylate, propylene acrylate, isopropyl acrylate). . The monomer component (precursor) constituting the propylene resin 31 resin preferably has a molecular weight of 200 to 700. Specific examples of the monomer component (precursor) constituting the acrylate resin include pentaerythritol triacrylate (PETA (pentaerythritol triacrylate): molecular weight: 298) and neopentyl glycol diacrylate (NPGDA (neopentyl glycol diacrylate). ): molecular weight: 212), dipentaerythritol hexaacrylate (molecular weight: 632), 147072.doc 201042294 dipentaerythritol pentaacrylate (molecular weight: 578), trioxindole Methyl propane triacrylate (TMPTA (trimethylolpropane triacrylate): molecular weight 296). Such a monomer component (precursor) is preferred because it has a molecular weight and a three-dimensional structure suitable for infiltration into a crosslinked structure (three-dimensional network structure) of light diffusing fine particles. An initiator can also be added as needed. As the initiator, for example, UV (ultravi〇let, ultraviolet) radical generator (Ciba essence (Ciba) can be cited.

Specialty Chemicals) Irgacure 907, Irgacure 127, Irgacure 192, etc., benzoquinone peroxide. The resin component may contain other resin components in addition to the ionizing radiation curable resin. The other resin component may be an ionizing radiation curable resin, a thermosetting resin, or a thermoplastic resin. Representative examples of other resin components include aliphatic (e.g., polyolefin) resins and amine ester resins. In the case of using other resin components, the kind or the amount of blending is adjusted so that the above-mentioned concentration modulation region is favorably formed, and the refractive index satisfies the relationship of the above formula (1). The refractive index of the above resin component is preferably from 1.40 to 1.6 Å. The compounding amount of the above resin component in the coating liquid is preferably from 20 parts by weight to 80 parts by weight, more preferably from 45 parts by weight to 65 parts by weight, based on 100 parts by weight of the substrate to be formed. Α-1-2. Ultrafine particle component The above ultrafine particle component is typically used as a component for adjusting the refractive index of the matrix. By using the ultrafine particle component, the refractive index of the matrix can be easily adjusted, thereby expanding the refractive index of the light diffusing fine particles and the matrix. In particular, according to the present invention, the penetration of the resin component into the inside of the light diffusing fine particles increases the concentration of the ultrafine particle component in the matrix, and the refractive index difference between the matrix and the light diffusing fine particles is easily expanded. As a result, = light diffusion having a high haze value (strong diffusibility) is obtained as a film: the refractive index nB of the ultrafine particle component should satisfy the following formula (2): 〇 < I nP-nA | < | nP-nB | · · · (7). In the formula (2), 'and' are as described above.丨np_nB should be 〇 1〇~丨5〇, more preferably 0.20~0.80. If 丨np_nB丨 is less than 〇1, most cases are 90% or less. As a result, there is a possibility that the light source from the light source cannot be sufficiently diffused when it is loaded into the liquid crystal display device, so that the viewing angle is narrowed. If 丨nP-nB| exceeds 1.50, there is a tendency for backscattering to increase. The ultrafine particle component preferably contains a compound different from the above resin component and light diffusing fine particles, and more preferably contains an inorganic compound. Preferred examples of the inorganic compound include metal oxides and metal fluorides. Specific examples of the metal oxide include zirconia (refractive index: 2.19), oxidation (refractive index: 丨56 to 2 62), titanium oxide (refractive index: 2.49 to 2.74), and cerium oxide. (refractive index: 125~146). Specific examples of the metal fluoride include magnesium fluoride (refractive index: 丨.37) and calcium fluoride (refractive index: 1.40 to 1.43). These metal oxides and metal fluorides have less absorption of light, and have a refractive index which is difficult to be expressed in an organic compound such as an ionizing radiation-curable resin or a thermoplastic resin, thereby expanding the refractive index difference between the light-diffusing particles and the matrix. . Further, since these metal oxides and metal fluorides have appropriate dispersibility with the resin component, other concentrations can be formed in the vicinity of the interface between the light diffusing fine particles and the substrate (the peripheral portion of the light diffusing fine particles). 147072.doc 10 201042294 Variable region - This other concentration-modulating region is also formed outside of the light-diffusing particles. In the case of p, the backscattering can be further suppressed as compared with the case where the concentration modulation region is formed only inside the light diffusing fine particles. Inorganic compounds are particularly good & oxidation. This is because the difference in refractive index from the light diffusing fine particles is large, and the dispersibility with the resin component is appropriate, so that other concentration-modulating regions having desired characteristics (or structures) can be favorably formed. Further, in the present invention, the concentration 〇 modulation region may be formed inside the vicinity of the surface of the light diffusing fine particles, and the other concentration modulation regions may not be formed. X The refractive index of the above ultrafine particle component is preferably 14 〇 or less or 16 〇 or more :: for (four) the following red 70 to 2.8 〇, Xiao Jia is i 4 〇 or 2 〇〇 〜 2 8 〇. When the right refractive index exceeds 1.40 or does not reach uo, the refractive index difference between the light diffusing fine particles and the substrate may be insufficient, and when the obtained light diffusing element is used in a liquid crystal display device for collimating the backlight front diffusion system, The inability to fully expand the light from collimating the backlight causes the viewing angle to narrow. The ultrafine particle component may also have a reduced refractive index by being made porous. The average particle diameter of the above ultrafine particle component is preferably from 1 nm to 1 Å, more preferably from 10 nm to 8 Å, and still more preferably from 2 Å to 7 〇 nm. Thus, by using an ultrafine particle component 'having an average particle diameter smaller than the wavelength of light, a matrix which is optically uniform without causing geometric optical reflection, refraction, and scattering between the ultrafine particle component and the resin component can be obtained. As a result, an optically uniform optical diffusing element can be obtained. The above ultrafine particle component preferably has good dispersibility with the above resin component. In the present specification, the term "good dispersibility" means applying the resin component, the ultrafine particle component, (a small amount of a uv initiator as needed), and volatilizing 147072.doc -11 - 201042294 and drying the solvent. The coating liquid obtained by mixing the solvent was removed, and the coating film was made transparent. The above ultrafine particle component should preferably be surface modified.

Specific examples thereof include a coupling agent such as a decane coupling agent or a titanium titanate coupling agent, and a surfactant such as a fatty acid surfactant.使用 By using such a surface modifier, the wettability of the resin component and the ultrafine particle component can be improved, the interface between the resin component and the ultrafine particle component can be stabilized, and the ultrafine particle component can be well dispersed in the resin component, and is good. The above other concentration modulation regions are formed. The amount of the ultrafine particle component in the coating liquid is preferably from 1 part by weight to 70 parts by weight, more preferably from 35 parts by weight to 55 parts by weight, based on 100 parts by weight of the substrate to be formed. A·1·3. Light-diffusing fine particles The light-diffusing fine particles may contain any suitable material as long as the concentration-modulating region can be formed satisfactorily. The refractive index of the above light diffusing fine particles preferably satisfies the relationship of the above formula (1). As described above, the light diffusing fine particles preferably contain a compound which is homologous to the resin component of the above matrix. For example, when the ionizing radiation-curable resin constituting the resin component of the matrix is an acrylate-based resin, the light-diffusing fine particles are preferably 147072.doc •12·201042294. More specifically, when the monomer component of the acrylate resin constituting the resin component of the matrix is, for example, the above-mentioned PETA, NPGDA, DPHA, DPPA, and/or hydrazine, the acrylic vinegar resin constituting the light diffusing fine particles should preferably be It is a polymethyl methacrylate (PMMA), a polymethyl methacrylate (PMA), and a copolymer of these and the like. Examples of the copolymerization component with PMMA and PMA include polyamine vinegar, polystyrene (PSt, p〇lystyrene), and melamine resin. The light diffusing fine particles are particularly preferably composed of PMMA. The reason for this is that the relationship between the refractive index or the thermodynamic property of the resin component of the matrix is appropriate. Further, the light diffusing fine particles preferably have a crosslinked structure (three-dimensional network structure). Light diffusing particles having a parent structure can be swollen. Therefore, such light-diffusing fine particles are different from dense or solid inorganic particles, and the resin component having the appropriate compatibility can be well penetrated into the interior thereof. The crosslink density of the light-diffusing particles is preferably small (sparse) to the extent that the desired penetration (described below) can be obtained. For example, the degree of swelling of the light diffusing fine particles in the coating liquid with respect to the resin component precursor (which may also include a solvent) is preferably determined. The term "swelling degree" as used herein refers to the ratio of the average particle diameter of the particles in the swollen state to the average particle diameter of the particles before swelling. The average particle diameter of the light-diffusing fine particles is preferably i _ 5 5 (four), more preferably 〜 4 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 Light-diffusing particles ^ ώ Τ <The average particle size should be less than 1/2 of the thickness of the light-diffusing element (for example, 1/2 to 1/2 mouthpieces). The average particle diameter allows a plurality of light diffusing fine particles to be aligned in the direction of the light diffusing element, so that the light can be multi-diffused at the incident light 147072.doc 201042294, and as a result, the period during which the light diffusing element can be transmitted is sufficient. Light diffusivity. The weight average particle size distribution of the light diffusing fine particles is preferably 1 〇 μπ^ or less, more preferably 〇5 (4) or less. When a plurality of light-diffusing fine particles having a small particle diameter and a small average particle diameter are mixed, the diffusibility is excessively increased, and the backscattering cannot be satisfactorily suppressed. When a plurality of "light-diffusion particles having a large average particle diameter are mixed, there are cases where a plurality of light-diffusing fine particles cannot be arranged in the thickness direction of the light-diffusing element, and multiple expansions cannot be obtained. As a result, there is light diffusion. The shape of the light diffusing fine particles may be any suitable shape depending on the purpose. Specific examples thereof include a spherical shape, a scaly shape, a plate shape, an elliptical shape, and an amorphous shape. In many cases, spherical spherical particles may be used as the light diffusing fine particles. The refractive index of the light diffusing fine particles is preferably 〖. 〜 丨 7 〇, more preferably 1 · 40 〜 1 · 60 〇 relative to The amount of the light diffusing fine particles in the coating liquid is preferably from 10 parts by weight to 100 parts by weight, more preferably from 15 parts by weight to 40 parts by weight, based on the weight of the substrate. The light diffusing fine particles having an average particle diameter of the above preferred range can obtain a light diffusing element having excellent light diffusibility. Α_1-4. The overall composition of the coating liquid is used as the above volatile solvent. Any suitable solvent can be used as long as the above components can be dissolved or uniformly dispersed. Specific examples of the volatile solvent include ethyl acetate, butyl acetate, and isopropyl acetate '2-butanone (A 147072). .doc -14- 201042294 base ethyl ketone), mercaptoisobutyl ketone, cyclopentanyl, acetophenone, isopropanol, n-butanol, cyclopentane, water. The above coating liquid can be further contained according to the purpose For example, in the case of using the above ultrafine particle component, a dispersing agent can be suitably used in order to disperse the ultrafine particle component well. Examples of other specific examples of the additive include an anti-aging agent, a modifier, and an interface. Active agent, anti-tarnishing agent, ultraviolet absorber, leveling agent, antifoaming agent. The solid content concentration of the coating liquid can be adjusted.

. / 〇 ~ 70% by weight or so is appropriate. As long as such a solid component concentration is obtained, a coating liquid having an easily applied viscosity can be obtained. Α-2. Step Β As a method of allowing at least a part of the precursor to permeate into the inside of the light diffusing fine particles in the step, a method of allowing the coating liquid to stand is exemplified. The resin component and the light diffusing fine particles preferably contain the same material, and more preferably contain a material having high compatibility. Therefore, the resin component is preliminarily discharged by leaving the coating liquid without special treatment or operation. It will penetrate into the light diffusing particles (4). That is, by bringing the resin = precursor to the light diffusing particles for a specific time, the resin component will penetrate into the light diffusing particles. The standing time should be The particles of the light diffusing particles are substantially far from the fear...: 'It should be longer when the first shellfish is maximized: the so-called "the size of the light diffusing particles is substantially the largest, go φ, stop the core until the light diffusing particles swell to the maximum without being called the maximum swelling time (hereinafter, also by making the resin component precursor and light diffusion 147072.doc 15 201042294 When it is contacted for a longer period of time, the penetration of the light-diffusing particles by the tree-ride component precursor will reach a saturated state, and it will not be able to further enter the cross-linked structure inside the light-diffusing particles. In order to achieve good and stable light diffusibility by the following polymerization step: a concentration modulation region is formed in the vicinity of the polymerization step. The maximum swelling time may vary depending on the compatibility of the resin component and the light diffusing fine particles. The standing time may vary depending on the constituent materials of the resin component and the light diffusing fine particles. For example, the standing time is preferably from 1 hour to 48 hours, more preferably from 2 hours to 4 hours, and still more preferably from 3 hours to 3 hours. 5 hours, particularly preferably 4 hours to 3 hours. If the amount of standing is less than 1 hour, there is a case where the precursor does not sufficiently penetrate into the inside of the light diffusing fine particles, and as a result, the formation does not form well. In the case of a concentration-modulated region, if the standing time exceeds 48 hours, there may be a physical interaction between the light-diffusing particles, and the viscosity of the light-diffusing microparticles can be increased. Insufficient. The standing can be carried out under the chamber. It can also be carried out under the specific temperature conditions set according to the purpose or the material used. In the step B, the precursor is only from the surface of the light diffusing particles. It is sufficient to penetrate into one part of the light diffusing fine particles, for example, preferably to the range of 10% to 95% of the average particle diameter of the light diffusing fine particles. When the penetration range is less than 1%, there is no possibility. The concentration modulation region is formed well and the backscattering cannot be sufficiently reduced. Even if the penetration range exceeds 95% ', as in the case where the penetration range is small, the concentration modulation region is not formed well and the back cannot be sufficiently lowered. In the case of scatter, the penetration range can be controlled by adjusting the resin composition and the material of the light diffusing fine particles, the crosslinking density of the light diffusion, the standing time, the standing temperature, and the like. In the present invention, it is important to control the penetration of the precursor into the light diffusing fine particles. For example, as shown in FIG. 3, after the preparation of the coating liquid, the coating liquid is applied to the substrate to form light diffusion. In the case of components, the diffuse half-value angle varies greatly depending on the drying temperature. On the other hand, when the coating liquid is allowed to stand for 24 hours and then applied to a substrate to form a light diffusing element, the diffusion half angle is substantially fixed without being affected by the drying temperature. The reason for this is considered to be that the precursor is driven to the state in which the light-diffusing particles penetrate to the saturated state by standing, so that the formation of the concentration-modulating region is not affected by the drying temperature. Therefore, as described above, the rest time should be longer than the maximum swelling time. By setting the standing time in this manner, it is possible to obtain a substantially fixed and good diffusion half-value angle without being affected by the drying time, and therefore it is possible to stably manufacture a light diffusing element having high diffusibility without any deviation. Further, for example, it can be produced by low temperature drying of 6 (TC), and therefore it is preferable in terms of safety or cost. On the other hand, it can be determined according to the type of precursor and light-diffusing smear particles until the penetration reaches saturation. In the time until the state, even if the standing time is shortened, the light diffusing element having high diffusibility can be stably produced without any deviation by appropriately selecting the drying temperature. For example, even after the preparation of the above coating liquid, the coating liquid is applied. When the light diffusing element is formed on the substrate, the drying temperature can be set to 1〇〇7, so that the Moon and the J are penetrated into the light diffusing fine particles to form a concentration modulation region. The light diffusing element having high diffusibility is stably produced without deviation. A-3·Step c Typically, the above coating liquid is applied before step 147 (the step of polymerizing the precursor) 147072.doc -17- 201042294 It can be applied to a substrate. Any suitable film can be used as the substrate as long as the effect of the present invention can be obtained. Specific examples thereof include triacetyl cellulose (TAC, triacetyl celiui). Se) film, polyethylene terephthalate (PET) film, polypropylene (PP) film, nylon film, acrylic film, lactone modified acrylic film, etc. If necessary, it is easy to carry out the treatment, such as surface modification, and may also include a lubricant, an antistatic agent, and an ultraviolet absorber. The substrate may be used as a protective layer in the polarizing plate with the light diffusing element described below. In the case of applying the coating liquid to the substrate, any suitable coating machine can be used. Specific examples of the coating machine include a bar coater and a counter. To the coater, the coater, the gravure coater, the die coater, and the knife coater. Next, the precursor is polymerized. The polymerization method can be based on the type of the resin component (and thus its precursor). In any case, when the resin component is an ionizing radiation-curable resin, the precursor is polymerized by irradiation with ionizing radiation. Ultraviolet rays are used as ionizing radiation. In the case of the line, the cumulative light amount is preferably 200 mJ to 400 mJ. The penetration rate of the ionizing radiation with respect to the light diffusing fine particles is preferably 70% or more, more preferably 80% or more. Further, for example, the resin component is thermosetting. In the case of a resin, the precursor is polymerized by heating. The heating temperature and the heating time can be appropriately set depending on the type of the resin component. The polymerization is preferably carried out by irradiating the ionizing radiation. When the refractive index distribution structure (concentration modulation region) is well maintained, the coating film is hardened 147072.doc -18- 201042294. Therefore, a light diffusion element having good diffusion characteristics can be produced. By polymerizing the precursor The matrix is formed, and at the same time, a "Zhangdu modulation region" is formed inside the surface of the light diffusing fine particles. More specifically, the concentration modulation region is formed by polymerization of a precursor which has penetrated into the light diffusing fine particles; the matrix is formed by polymerization without being infiltrated into the light diffusing fine particles. That is, according to the production method of the present embodiment, the precursor which has penetrated into the inside of the light diffusing fine particles and which does not penetrate into the light diffusing fine particles

The precursor is simultaneously polymerized, and a concentration-modulating region is formed inside the surface of the light-diffusing fine particles, and a matrix is simultaneously formed. In one embodiment, another concentration modulation region may be formed in the vicinity of the interface between the light diffusing fine particles and the substrate (the peripheral portion of the light diffusing fine particles). The other concentration-modulating regions are mainly formed by the compatibility of the resin component, the ultrafine particle component, and the light diffusing fine particles. The method for producing the light diffusing element of the present invention may of course include any suitable steps, processes and/or operations at any suitable point in time, in addition to the above steps A to C. The types of such steps and the like, and the timing at which such steps are performed, etc., can be appropriately set depending on the purpose. For example, the method for producing a light-diffusing 7G member of the present invention may include, as needed, a step of dry-welding a coating liquid applied to a substrate, ^ ^ ^ ^, ▲ 屎. For example, the drying of the crucible can be carried out, for example, in the case of polymerization, or after the polymerization step. The drying method of the coating liquid can be carried out by any appropriate method. As a specific example, it can be listed as white, ... Heating and drying 'decompression dry welding. Heating and drying is appropriate. Add 埶 warm axe main. ', ... gamma degrees for example 60 (: ~ 1 50. (:, crowned Japanese R roll for example 30 seconds ~ 5 minutes. ... 147072.doc -19· 201042294 The light diffusing element is formed on the substrate in the above manner. The obtained light diffusing member can be peeled off from the substrate and used as a single member, and can also be used as a substrate-attached light. 70 pieces may be used as a composite member (for example, a polarizing plate with a light diffusing element) by transferring a substrate to a polarizing plate or the like, or may be attached to a polarizing plate or the like together with a substrate to be used as a composite member (for example, a polarizing plate with a light diffusing element). When used as a composite member (for example, a polarizing plate with a light diffusing member) together with a substrate and attached to a polarizing plate, the substrate can be used as a protective layer of a polarizing plate. And play a role. Β. Light diffusing element The light diffusion of the present invention The material can be obtained by the method described in the above items A-1 to Α3. The light diffusing element of the present invention contains a matrix containing a resin component and an ultrafine particle component, and light diffusing fine particles dispersed in the matrix. The light diffusing element exhibits a light diffusing function by a difference in refractive index between the substrate and the light diffusing fine particles. The figure is used to explain the matrix in the light diffusing element obtained by the manufacturing method of the preferred embodiment of the present invention. A schematic diagram of a state in which the resin component and the light diffusing fine particles are dispersed. The light diffusing element 100 of the present invention includes a matrix 10 containing a resin component U and an ultrafine particle component 12, and light diffusing fine particles 2〇 dispersed in the matrix 1〇. The refractive index of the resin component and the light diffusing fine particles of the matrix preferably satisfy the following formula (丨): 〇 &lt; | nP-nA | · (1) The refractive index of the above ultrafine particle component satisfies the following formula (2) 〇 lt | | 树脂 树脂 树脂 树脂 树脂 树脂 树脂Ultrafine particle composition Borrowing 147072.doc • 20· 201042294 It is possible to obtain a light diffusing element which maintains a high haze and suppresses backscattering. In the light diffusing element of the present invention, a concentration is formed inside the surface of the light diffusing fine particle 20 The modulation region 30. As described in the above items A-1 to A-3, the concentration modulation region 30 is polymerized by the resin component 11 precursor (monomer) permeating into the interior of the light diffusing fine particles 20 In one embodiment, the weight concentration of the resin component 11 is fixed in the concentration-modulating region 30. In another embodiment, in the concentration-modulating region 3, the resin component 11 is The weight concentration decreases as it goes away from the surface of the light diffusing fine particles 2 (i.e., 'as it goes toward the center of the light diffusing fine particles 20). The concentration modulation region 30 is preferably formed inside the light diffusing fine particles 2, and as such, the effect can be exerted. For example, the concentration modulation region is formed in a range from 丨〇% to 95% of the average particle diameter of the light diffusing fine particles 20 to the light diffusing fine particles. The thickness of the concentration-modulating region 30 (the distance from the surface of the light-diffusing particle to the innermost portion of the concentration-modulating region) may be fixed or different depending on the position of the surface of the diffusing particle. The thickness of the concentration modulation region 30 is preferably 100 nm to 4 μm, more preferably 1 nm to 2 μm. The resin component is infiltrated to form the concentration-modulating region 30', whereby the following effects can be obtained: ()) the refractive index can be changed stepwise or substantially continuously in the vicinity of the interface between the light-diffusing particles and the substrate (refer to FIG. 2 (refer to FIG. 2 a)). On the other hand, in the prior light diffusing element, the concentration modulation region is not formed, and the interface between the particles and the substrate is obvious, so the refractive index changes intermittently from the refractive index of the particles to the refractive index of the matrix (refer to FIG. 2). (b)). As shown in Fig. 2(a), the concentration modulation region 3〇 is formed so as to be near the interface between the substrate 1 〇 and the light diffusing fine particles 2 折射率 refractive index phase 147072.doc -21 - 201042294 or substantially continuous The ground change "by this, even if the refractive index difference between the base (4) and the light diffusing element 20 is increased, the reflection at the interface between the substrate and the light diffusing fine particles can be suppressed, and backscattering can be suppressed. On the other hand, Fig. 2 (8) does not, according to the previous light diffusing element, when it is intended to impart a strong diffusibility by expanding the refractive index difference (age g Φ ώ + month and r I 钗 haze value) When it is impossible to eliminate the difference in refractive index on the interface. As a result, the backscattering due to interface reflection becomes large: (7) the formation of other concentration-modulating regions mainly due to the ultrafine particle component can promote the formation thereof; (3) the resin component (1) is penetrated to The inside of the light diffusing fine particles 20 is lower than that of the non-infiltrated material, and the resin 1 of the base 1G towel is reduced. As a result, the refractive index of the ultrafine particle component ι2 contributes to the refractive index of the entire matrix. Therefore, when the refractive index of the ultrafine particle component is large, the refractive index of the entire matrix increases (instead, in the ultrafine particle component). When the refractive index is small, the refractive index of the entire matrix becomes small, and the difference in refractive index between the matrix and the light diffusing fine particles is further increased. Therefore, higher diffusibility (haze value) can be achieved as compared with the case where the resin component is not permeable. As described in the above items A-1 to A_3, the concentration modulation region can be formed by appropriately selecting a constituent material of the resin component and the light diffusing fine particles of the matrix, and chemical and thermodynamic properties. For example, a resin component and light diffusing fine particles are composed of a material having a high compatibility in a homologous material, whereby a concentration-modulated region can be favorably formed. The thickness and concentration gradient of the concentration modulation region can be controlled by adjusting the chemical composition and thermodynamic properties of the resin component of the matrix and the light diffusing particles. According to the type of the resin component and the light diffusing fine particles described above, 147072.doc -22- 201042294 is appropriately selected to be in the vicinity of the interface between the substrate 10 and the light diffusing fine particles 2 (light diffusing fine particles) The peripheral portion further forms another concentration modulation region (not shown). For example, a resin component and a light-diffusing fine particle ' are composed of a material of the same type (for example, an organic compound), and a fine particle component is formed of a material (for example, an inorganic compound) different from the resin component and the light diffusing fine particle. The ground forms other concentration modulation regions. More specifically, the resin component is partially surrounded by the light diffusing fine particles, and the light diffusing fine particles are uniformly dissolved or dispersed in the vicinity of the light diffusing fine particles. The energy is stable. As a result, the weight concentration of the resin component is higher in the region closest to the light diffusing fine particles than the average weight concentration of the resin component in the entire matrix, and decreases as the light diffusing fine particles are separated. Therefore, other concentration modulation regions can be formed. In the other concentration-modulating region described above, as the light-diffusing fine particles 20 are distant from each other, the weight concentration of the resin component 11 is lowered, and the weight concentration of the ultrafine particle component is increased. In other words, in the region closest to the light diffusing fine particles 20 in the other concentration modulation region, the ultrafine particle component is dispersed at a relatively low concentration, and the concentration of the ultrafine particle component increases as it is distant from the light diffusing fine particle 20. Large = For example, in the region of the other concentration-modulating region closest to the light diffusing fine particles 20, the weight concentration of the resin component is higher than the average weight concentration of the resin component in the entire matrix, and the weight concentration of the ultrafine particle component is lower than The average weight concentration of the ultrafine particle components in the matrix f body. On the other hand, in the farthest region from the light diffusing particles in the other/length modulation region, the weight concentration of the tree is equal to or sometimes lower than the resin composition in the matrix as a whole 147072.doc - 23-201042294 Average Weight Concentration 'The weight concentration of the ultrafine particle component is equal to or sometimes higher than the average weight concentration of the ultrafine particle component in the bulk of the matrix. By forming such other concentration-modulating regions also outside the light-diffusing particles, it is possible to increase the region in which the refractive index changes continuously in a stepwise or real-f (ie, from the inside of the light-diffusing particles) The concentration modulation region is changed to the other concentration modulation region outside the light diffusing fine particles, and the refractive index is changed stepwise or substantially continuously). As a result, the backscattering can be further suppressed as compared with the case where the concentration modulation region is formed only inside the light diffusing fine particles. Further, on the outer side of the other concentration modulation region, the weight concentration of the ultrafine particle component having a large difference in refractive index from the refractive index of the light diffusing fine particle 20 is relatively large, so that the matrix 1〇 and the light diffusing fine particle 2〇 can be enlarged. The difference in refractive index. As a result, even if it is a film, a high haze (strong diffusibility) can be achieved. Such a feature is particularly suitable for use in applications such as a light diffusing element used in a collimated backlight front diffusing system which requires a relatively high diffusibility (haze of 9 % or more). The thickness of the other concentration modulation region (the distance from the surface of the light diffusing particle to the end of the other concentration modulation region) may be fixed (that is, other concentration modulation regions may also be concentric around the light diffusing particles). The shape may be different depending on the position of the surface of the light diffusing fine particles (for example, the thickness of the outer contour such as the outer contour of the candy may be different depending on the position of the surface of the light diffusing fine particle. In such a configuration, the refractive index can be continuously changed in the vicinity of the interface between the substrate 10 and the light-diffusing fine particles 20. As long as the other concentration-modulated regions are formed in a sufficient thickness, the refractive index can be refracted in the peripheral portion of the light-diffusing particles. The rate is more smoothly connected with 147072.doc -24· 201042294, which can change the backscattering very effectively. On the other hand, if the thickness is too large, there are other concentration-modulating regions and even occupying the light diffusing particles. The area where it exists, and sufficient light diffusivity (such as haze value) cannot be obtained. Therefore, the thickness of other concentration-modulated areas It is H>nm~5〇〇nm, more preferably 2〇nm~4〇〇nm, and even more preferably 3〇(10)~300 nm. Moreover, the thickness of other concentration modulation regions is relative to the average of light diffusing particles. The particle size is preferably i G%~5G% 'better than · peach. Ο The higher the haze of the above light diffusing element, the better, specifically, 9 〇 to 99%, more preferably 92 to 99%. Further better for the heart (four), particularly preferably 97 to 99%. With a haze of 9% or more, it can be preferably used as a front light diffusing element in front of the collimated backlight front diffusing system. Further, the so-called collimated backlight The front diffusion system refers to a system in which a collimated backlight (a backlight that is concentrated in a fixed direction and has a narrow half-value width) is used in a liquid crystal display device, and a front light diffusing element is provided on the viewing side of the upper polarizing plate. .

The diffusion characteristics of the light diffusing element are preferably 10 as indicated by a half value angle of light diffusion. ~150. (single side 5. ~ 75.), more preferably 1 〇. ~1〇〇. (single 5°~50°), and more preferably 3〇. ~8〇. (single side 15. ~ 4 〇〇). Then, the position of the light diffusing element described above can be appropriately set depending on the purpose or the desired diffusion characteristics. Specifically, the thickness of the light diffusing element is preferably 4 μηη to 50 μηι, more preferably 4 μηη to 20 μηι. According to the present invention, a light diffusing member having a very high haze as described above can be obtained although it is a very thin thickness as described above. The light diffusing element is suitably used for a viewing side member of a liquid crystal display device, a backlight member for a liquid crystal display device, and a lighting fixture (for example, organic 147072.doc -25·201042294 EL(electroluminescence), led(1) coffee_outlight emission Diode)) is a diffusion member that is particularly suitable for use as a front diffusing element in front of a collimated backlight front diffusing system. The light diffusing element may be provided as a film or a plate member alone, or may be attached to any appropriate substrate or polarizing plate as a composite member. Further, an antireflection layer may be laminated on the light diffusing element. C. Polarizing plate with light diffusing element C-1. Whole polarizing plate with light diffusing element The manufacturing method of the polarizing plate with light diffusing element of the present invention is the use of the above items A-1 to A-3. The method for producing a light diffusing element of the present invention is described. The polarizing plate with a light diffusing element obtained by the manufacturing method of the present invention is typically disposed on the viewing side of the liquid crystal display device. Fig. 4 is a schematic cross-sectional view showing a polarizing plate of a light diffusing element according to a preferred embodiment of the present invention. The polarizing plate 2 of the light diffusing element includes a light diffusing element 100 and a polarizing element 110. The light diffusing element 1 is the light diffusing element of the present invention described in the above items A1 to A_3 and B. The light diffusing element 1 is disposed so as to be the most visible side when the polarizing plate attached to the light diffusing element is disposed on the viewing side of the liquid crystal display device. In one embodiment, a low reflection layer or an antireflection treatment layer (antireflection treatment layer) (not shown) is disposed on the viewing side of the light diffusing element 100. In the illustrated example, the polarizing plate 200 with the light diffusing element is provided on both sides of the polarizing element including the protective layers 12 and 130. The light diffusing element, the polarizing element and the protective layer are attached via any suitable adhesive layer or adhesive layer. At least one of the protective layers 12A and 130 may be omitted depending on the purpose, the constitution of the polarizing plate, and the composition of the liquid crystal display device 147072.doc • 26- 201042294. For example, when the substrate used for forming the light diffusing element can function as a protective layer, the protective layer 12A can be omitted. The polarizing plate with light diffusing element of the present invention is particularly suitable for use as a viewing side polarizing plate in a liquid crystal display device using a collimated backlight front diffusing system. C - 2. Polarizing element As the above-mentioned polarizing element 110, any appropriate one may be adopted depending on the purpose.

Polarized component. For example, hydrophilicity such as adsorption of a dichroic substance such as iodine or a dichroic dye to a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate-based copolymer system, or a partially saponified film The molecular film is uniaxially stretched; a polyether-based alignment film such as a dehydrated material of ethylene glycol or a dehydrochloric acid-treated product of a gas-gathered woman. Among these, it is preferable to use a dichroic substance such as ruthenium to absorb (4) a polyhedral alcohol-based film and to uniaxially extend the polarizing element. The thickness of these polarizing elements is not particularly limited, but is usually about 1 to 80 μηι. A polarizing element obtained by adsorbing iodine on a polyvinyl alcohol-based film and uniaxially stretching can be carried out, for example, by dipping the polyethyl ethoxylate film into a broken aqueous solution to carry out dyeing and stretching to 3 to 7 times of the original length. Production. If necessary, it may contain = or zinc sulphate, chlorinated, etc., or may be immersed in an aqueous solution such as Aihua, etc., or may be immersed in water before dyeing as needed. Washed with water. By performing the # Μ ^ ^ rule washing on the polyethylene fermentation membrane, not only the dirt or anti-swelling of the surface of the polyvinyl alcohol film can be washed away, but the dyeing unevenness is prevented from being caused by the dyeing of the polyethylene film. = effect. The extension can be extended on the side of the dyeing side, or it can be dyed with iodine after the extension of 147072.doc •27- 201042294. It may also be extended in an aqueous solution of boric acid or potassium iodide or in a water bath. C-3 · Protective layer The above protective layers 20 and 130 are formed of any suitable film which can be used as a protective layer of a polarizing plate. Specific examples of the material which is a main component of the film include cellulose-based resins such as triethyl cellulose (TAC); polyester-based polyvinyl alcohol-based, polycarbonate-based, polyamid-based, and polyfluorene-based polymers. A transparent resin such as an imide-based, poly-m-polystyrene-based, polyene-based, poly-smoke-based, (meth)acrylic, or acetate-based resin. Further, examples thereof include thermosetting resins such as (meth)acrylic acid, ammonia vinegar, (meth)acrylic acid vinegar, % oxygen, and xenon, and ultraviolet curable resins. In addition, a polymer film such as a siloxane polymer or a polymer film described in JP-A-2001-343529 (WO01/37007) can also be used. As the material of the film, for example, a thermoplastic resin having a substituted or unsubstituted quinone imide group in a side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain can be used. The resin composition may, for example, be a resin composition containing an alternating copolymer of isobutylene and N-methylbutylenimine and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extruded product of the above resin composition. The protective layer (inner protective layer) 130 is preferably optically isotropic. Specifically, the phase difference Rth (550) in the thickness direction of the inner protective layer is preferably -20 nm to +20 nm, more preferably _1 〇 nm to +1 〇 nm, and particularly preferably -6 nm to +6 nm, most Jia is · 3ηιη~+3ηηι. The inner protective layer 147072.doc • 28 - 201042294 The internal phase difference Re(550) should be below 10 nm below 〇 nm, more preferably below 6 nm above 0 nm, and especially below 3 nm above 3 nm. A specific example of a film which can form such a protective layer having an optically isotropic property is described in Japanese Laid-Open Patent Publication No. 2008-180961, the disclosure of which is incorporated herein by reference. D. Liquid crystal display device The method for producing a liquid crystal display device of the present invention is carried out by using the method for producing a light diffusing element of the present invention described in the above paragraphs 1-3 to A. Fig. 5 is a schematic cross-sectional view showing a liquid crystal display device obtained by a manufacturing method of a preferred embodiment of the present invention. The liquid crystal display device 5 includes: a liquid crystal cell 5 10; polarizing plates 520 and 530 disposed on both sides of the liquid crystal cell; a backlight unit 540 disposed outside the polarizing plate 530; and light disposed outside the polarizing plate 520 (viewing side) Diffusion element 1 〇〇. Any appropriate optical compensation plate (phase difference plate) may be disposed between the liquid crystal cells 51 and the polarizing plates 520 and/or 530, depending on the purpose. The liquid crystal cell 510 includes a pair of substrates (typically glass Q substrates) 511 and 512, and a liquid crystal layer 513 disposed between the substrates 511 and 512 and containing liquid crystal as a display medium. The light diffusing element 100 is the light diffusing element of the present invention described in the above items A-1 to A-3 and B. Alternatively, instead of the light diffusing element 1A and the viewing side polarizing plate 520, the polarizing plate with the light diffusing element of the present invention described in the above item C may be disposed. The light diffusing element penetrates and diffuses light transmitted through the liquid crystal cell (typically collimated light as described below). The above is a parallel light source device in which the light early element 540 emits collimated light toward the liquid crystal cell 510. The backlight unit can have any suitable configuration capable of emitting collimated light 147072.doc -29· 201042294. For example, the backlight unit includes a light source and a concentrating element (none of which is shown) for collimating the light emitted from the light source. In this case, as the concentrating element ‘, any concentrating element capable of collimating the light emitted from the light source can be used. When the light source itself can emit collimated light, the concentrating element can be omitted. The specific configuration of the backlight unit (parallel light source device) may be, for example, the following: (1) The lens focus on the flat side of the Lenticular Lens or the cannonball lens. A concentrating element provided with a light shielding layer or a reflective layer is disposed on a liquid crystal cell side of a light source (for example, a cold cathode fluorescent lamp) (for example, Japanese Patent Laid-Open Publication No. 2008-2620 12); The light guide plate ′ and the light guide plate side are formed with a convex surface and disposed at a liquid crystal cell side of the light guide plate. In the present configuration, an anisotropic diffusion element can be used as needed; for example, transcript Patent No. 3442247) (3) A configuration in which a light-absorbing resin and a transparent resin are alternately formed in a stripe-like light shielding layer between a backlight and a backlight-side polarizing plate (for example, Japanese Patent Laid-Open No. 2007-279424) (4) The use of a bullet-type LED as a light source (for example, Japanese Patent Laid-Open Publication No. Hei 6-13-255); (5) A configuration using a Fresnel lens and a diffusion plate used as needed ( For example, the above-mentioned publications having the detailed configurations described above are incorporated herein by reference. The liquid crystal layer 513 preferably includes a vertical display in black display. Liquid crystal molecules. Examples of the driving mode of the liquid crystal cell having such a liquid crystal layer include MVA (MulU-domain Vertical Alignment) mode and PVA (Pattern Alignment VA (Pattern Vertical Alignment). Doc -30- 201042294 to)) mode, TN (Twisted Nematic) mode, ECB (Electrically Controlled Birefringence) mode, OCB (Optically Compensated Bend 5 optically compensated bending) (bending nematic) (Bend nematic) mode. EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the examples. The evaluation methods in the examples are as follows. The "parts" and "%" in the examples are weight basis. (1) Thickness of light diffusing element The substrate and the light diffusing element are measured by a micrometer thickness gauge (manufactured by Mitutoyo Co., Ltd.). The total thickness is calculated, and the thickness of the light diffusing element is calculated by subtracting the thickness of the substrate from the total thickness. (2) The presence or absence of the concentration modulation region for the examples and comparison The laminated body of the light-diffusing element and the substrate obtained by the method is cooled by liquid nitrogen, and sliced to a thickness of 0.1 μm by a microtome to prepare a measurement sample. Using a transmission electron microscope (TEM) 〇n micr〇sc〇pe), the state of the particles of the light-diffusing component of the measurement sample was observed. The case where the contrast caused by the penetration of the precursor is confirmed in the inside of the particle is "the concentration adjustment = region", and the case where the contrast cannot be confirmed inside the particle and the uniform color is set to "no concentration modulation region" "." (3) Haze The haze is measured by a haze meter (Murako Color Department 147072.doc 31 201042294, Institute of Research, Ltd., trade name "HN_150") according to the method of the ancient and the earthworms specified in JIS 713. . (4) Light diffusion half-value angle The laser beam is irradiated from the front side of the light-diffusing element, and the diffusion brightness of the diffused light with respect to the diffusion angle is measured every 1° by a goniophotometer, as shown in Fig. 6. It is shown that the diffusion angle of the light from the diffused brightness maximum value to the half brightness of the light other than the direct penetration light of the laser is measured on both sides of the diffusion, and the angles of the two sides are added (the angle of the figure a + Angle A') acts as a light diffusion half value angle. (5) Backscattering ratio The laminate of the light-diffusing element and the substrate obtained in the examples and the comparative examples was bonded to a black acrylic plate (manufactured by Sumitomo Chemical Co., Ltd. under the trade name "SUMIPEX" (registered trademark). ), the thickness is 2 mm), and it is set as the measurement sample. The integral reflectance of the measurement sample was measured by a spectrophotometer (manufactured by Hitachi Instruments Co., Ltd., trade name "U4100"). On the other hand, a laminate obtained by removing fine particles from the coating liquid for a light-diffusing element is used to form a laminate of a substrate and a transparent coating layer, and is used as a control sample, and the integral is measured in the same manner as described above. The reflectance (i.e., surface reflectance) is calculated from the integrated reflectance of the sample & sample minus the integrated reflectance (surface reflectance) of the sample, thereby calculating the backscattering ratio of the light diffusing element. (6) The penetration range of the precursor is randomly selected from the photographs taken by the light diffusing particle sequence of the above-mentioned (2), and the diffusedness is selected for each of the selected light diffusing particles. Particle size and light expansion (4) "There is no" (4) 147072.doc -32- 201042294 The particle size of the part (non-permeable part), and the penetration range is calculated according to the following formula. The average value of the light diffusing particles is set as the penetration range. (Permeation range) = {1 - (particle diameter of non-permeable portion / particle diameter of light diffusing fine particles)} X100 (%) &lt;Example 1: Preparation of light diffusing element&gt; A hard coating resin (manufactured by JSR Corporation, trade name "Opstar KZ6661" (containing MEK (methyl ethyl ketone ' mercapto ethyl ketone), a component of oxidized tymallose particles (average particle diameter: 60 nm, refractive index: 2.19) /MIBK (methyl isobutyl ketone, fluorenyl isobutyl ketone)) 18.2 parts of the pentylene tetraacetate which is added as a resin component precursor (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", refractive index 1.52) 50% ΜΕΚ solution 6.8 parts, light t-starting agent (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name "Irgaeure9〇7") 〇. 68 parts, leveling agent (manufactured by DIC Corporation, trade name " GRANDIC PC 4100") 0.625 parts and polyacrylic acid ruthenium vinegar (PMMA) fine particles (manufactured by Kasei Kogyo Co., Ltd., trade name r artpearl J4P) as light diffusing fine particles, the average particle diameter is 2·1 μπι, and the refractive index is 1.49) 2.5 parts. The mixture was subjected to ultrasound for 5 minutes. The preparation was carried out to prepare a coating liquid in which the above components were uniformly dispersed. The coating liquid was applied onto a TAC film (manufactured by Fujifilm Co., Ltd., trade name "Fujitac") using a bar coater, and l〇〇° After drying for 1 minute, C was irradiated with ultraviolet light having an integrated light amount of 300 mJ to obtain a light diffusing element having a thickness of 15 μm. The obtained light diffusing element was used for the evaluation of the above (1) to (6). The results of Examples 2 to 4 are shown together in Table 1. Further, 'Photograph of the cross section of the light diffusing element is shown in Fig. 7. 147072.doc • 33- 201042294 According to the TEM photograph, it is confirmed that the light diffusibility is obtained. A concentration-modulating region was formed inside the fine particles. <Example 2: Preparation of Light-Diffusing Element> A coating liquid was prepared in the same manner as in Example 1. After the coating liquid was allowed to stand for 4 hours, The coating was carried out in the same manner as in Example 1. A light diffusing element was obtained in the same manner as in Example 1 except that the drying temperature after the coating was changed to 60 ° C and the thickness was set to 1 μμηη. The obtained light diffusing element is used for the evaluation of (1) to (6) above. The results are shown in Table 1. <Example 3: Preparation of light diffusing element> The same manner as in Example 1 except that the dry temperature after applying the coating liquid was 6 Torr. The light diffusing element was obtained, and the obtained light-diffusing 7G piece was used for the evaluation of the above (1) to (6). The results are shown in Table 1. Further, the TEM photograph of the light-diffusing element scraping surface is shown in Fig. 7. According to this tem photograph, it was confirmed that a concentration modulation region was formed inside the light diffusing fine particles. &lt;Example 4: Production of Light-Diffusing Element&gt; Using PMMA fine particles (manufactured by Konica Chemical Co., Ltd., Μχι8〇ΤΑ) as light-diffusing fine particles, and having a thickness of 2 μm, The light diffusing element was obtained in the same manner as in Example 1. The obtained light diffusing element was used for the evaluation of the above (1) to (6). The results are shown in the table. Further, a photograph of the cross section of the light diffusing element is shown in Fig. 7. According to the photographic film, it was confirmed that a concentration modulation region was formed inside the light diffusing fine particles. &lt;Example 5: Production of Light-Diffusing Element&gt; A coating liquid was prepared in the same manner as in Example 1. After the coating liquid was allowed to stand for 2 hours, a light diffusing element was obtained in the same manner as in Example 2. The light diffusing element known from 147072.doc 201042294 is used for the evaluation of the above (1) to (6). The results are shown in Table 1. &lt;Example 6: Production of light diffusing element&gt; A coating liquid was prepared in the same manner as in Example 1. After the coating liquid was allowed to stand for 7 hours, a light diffusing element was obtained in the same manner as in Example 2. The obtained light was diffused by 70 pieces for the above evaluation. The results are shown in Table 1. &lt;Example 7··Preparation of light diffusing element&gt; A coating liquid was prepared in the same manner as in Example 1. After the coating liquid was allowed to stand for 24 hours, a light diffusing element was obtained in the same manner as in Example 2. The obtained light diffusing element was used for the evaluation of the above (1) to (6). The results are shown in Table 1. [Table 1] Settling time (h) Drying temperature CC) Permeation range (%) Thickness (μιη) Haze (%) Light diffusion half value angle (.) Backscattering rate (0/Λ Example 1 0 100 76.3 15 98.4 62 〇39 - Example 2 4 60 79.5 10 98.5 63 ~〇4? Greedy Example 3 0 60 27.7 15 95.4 32 0 19 Example 4 0 100 25.8 20 98.3 60 0.50~ Example 5 2 60 54.9 10 97.7 45 0.31 Example 6 7 60 81.3 10 98.5 63 0.43 \trnm 24 60 81.5 10 98.5 63 0.45 &lt;Example 8: Production of liquid crystal display device&gt; Commercially available liquid crystal television from liquid crystal cell including multi-domain type VA mode (Manufactured by s〇NY, BRAVIA20, trade name "KDL20J3000"), the liquid crystal cells are taken out. On both sides of the liquid crystal cell, a commercially available polarizing plate is attached to each other so that the absorption axes of the respective polarizing elements are orthogonal. Manufactured by the Electrician Co., Ltd., 147072.doc • 35- 201042294, the product name "NPF-SEG1423DU". More specifically, the absorption axis direction of the polarizing element of the backlight-side polarizing plate is perpendicular (relative to the longitudinal direction of the liquid crystal panel) 90°), and the absorption axis of the polarizing element of the polarizing plate In the horizontal direction (the direction in which the longitudinal direction of the liquid crystal panel is 〇.), the light diffusing element of Example i is transferred from the substrate and bonded to the outside of the viewing side polarizing plate. On the other hand, on one side of the PMMA sheet, the pattern of the lentil lens is melt-transferred using a transfer roller, on the surface (smooth surface) opposite to the surface on which the lens pattern is formed, so that The pattern of aluminum was vapor-deposited only by penetrating the focus of the lens, and a reflective layer having an area ratio of the opening portion of 7% (the area ratio of the reflecting portion was 93%) was formed. The concentrating element was fabricated in this manner. Lamp (10) manufactured by NY Company, BRAVIA2〇J CCFL (c〇id(10) side F1U〇reSCeiU LamP, cold cathode discharge lamp)) as a light source of backlight, a concentrating element is mounted on the light source, and parallel light that emits collimated light is produced. Light source device (backlight unit). A liquid crystal display device in which the above-described backlight unit is incorporated in the above liquid crystal panel to produce a collimated backlight diffusion system. A a ^ 胄 (4) liquid crystal display device In the dark place the white display and black display, and visually observe its display status. The result is 'displayed from the oblique direction of the ancient: a black display that is darker and white in the dark. The display is excellent in terms of goodness. <Evaluation> From the sequential description and the description of the examples, it is known that the method of manufacturing the element does not require the treatment or operation of light diffusion according to the present invention (essentially, 147072. Doc-36-f 201042294 A light diffusing element having a concentration-modulating region can be produced only by polymerizing the precursor after mixing the light-diffusing particles with the matrix resin component. By using such a light diffusing element for a liquid crystal display device for collimating a backlight front diffusing system, it is possible to obtain a liquid crystal having a good display characteristic in which a black display in a bright portion is black and a white display in a dark portion has a high luminance. Display device. Further, comparing Examples 1 to 3 and 5 to 7, it is understood that as long as the penetration of the precursor into the light diffusing fine particles is saturated, the longer the static standing time, the higher the diffusibility is obtained. When the light diffusing element has reached a saturated state, the diffusibility of the obtained light diffusing element is substantially constant even if the standing time becomes long. In addition, it can be seen that by ensuring a specific resting time to form a concentration-modulating region, even if drying at a low temperature, it is possible to obtain a light diffusing element having a haze value (the cost and safety of low-temperature drying in manufacturing) Excellent in terms of sex, so it is better). Industrial Applicability The light diffusing element and the light-diffusing element-attached polarizing plate obtained by the manufacturing method of the present invention are suitable for use as a viewing side member of a liquid crystal display device, a backlight member for a liquid crystal display device, and a lighting fixture. (For example, organic EL, LED) With a diffusion member, it is particularly suitable for use as a front diffusing element in front of a collimated backlight front diffusion system. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view for explaining a dispersion state of a resin component and a light diffusing fine particle of a matrix in a light diffusing element obtained by a manufacturing method of a preferred embodiment of the present invention; a) is used to illustrate the conceptual diagram of the refractive index change from the center of the particle to the substrate in the light diffusing element of the present invention, and FIG. 2(b) is used to illustrate the previous A conceptual diagram of the change in refractive index from the center of the particle to the substrate in the light diffusing element; FIG. 3 is a graph showing the relationship between the drying temperature and the obtained diffusion half-value angle for the coating liquid having different standing times; 4 is a schematic cross-sectional view of a polarizing plate with a light diffusing element obtained by the manufacturing method of the preferred embodiment of the present invention; and FIG. 5 is a schematic view of a liquid crystal display device obtained by the manufacturing method of the preferred embodiment of the present invention. FIG. 6 is a schematic view for explaining a method of calculating a half-value angle of light diffusion; and FIG. 7 is a view showing a transmissive display of a concentration modulation region of the light diffusing elements of Embodiments 1, 3, and 4. Micrograph. [Description of main components] 10 Substrate 11 Resin component 20 Light diffusing fine particles 30 Density modulation region 100 Light diffusing element 110 Polarizing element 120 Protective layer 130 Protective layer 200 Polarizing plate with light diffusing element 500 Liquid crystal display device 147072.doc - 38-

Claims (1)

201042294 VII. Patent application scope: 1. A method for manufacturing a light diffusing element, comprising the steps of: contacting a matrix forming material comprising a resin component precursor and an ultrafine particle component with light diffusing particles; At least a portion of the material diffuses into the interior of the light diffusing fine particles; and simultaneously forms a precursor containing the tree before it penetrates into the internal precursor of the light diffusing fine particles and does not penetrate the light diffusing fine particles And a matrix of the ultrafine particle component, and at the same time, a concentration modulation region is formed inside the surface of the light diffusing fine particle. 2. The method of producing a light diffusing element according to claim 1, wherein in the permeating step, the precursor is allowed to permeate from the surface of the light diffusing fine particles to 1% or more of an average particle diameter of the light diffusing fine particles. 9 5 % or less. 3. The method of producing a light diffusing element according to claim 1 or 2, wherein a time period in which the precursor of the resin component and the light diffusing fine particle are substantially larger than a particle diameter of the light diffusing fine particle is substantially greater Long time. 4. The method of producing a light-diffusing element according to claim 1, wherein the resin component is ionized radiation-curable resin, and the resin component precursor is polymerized by irradiation of ionizing radiation. A light diffusing element obtained by the method of any one of claims 1 to 4, comprising a matrix comprising a resin component and an ultrafine particle component, and light diffusing particles dispersed in the matrix; Further, 147072.doc 201042294 has a concentration modulation region formed by permeation of the resin component in the vicinity of the surface of the light diffusing fine particles. 6. A method of producing a polarizing plate with a light diffusing element, which is a method of manufacturing a light diffusing element according to any one of claims 1 to 4. Manufacture of a liquid crystal display device The method of manufacturing a light diffusing element according to any one of the claims is provided. 147072.doc -2-