JP6736381B2 - Optical laminate, polarizing plate and display device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical laminate suitable for an antiglare film, and a polarizing plate and a display device using the same.

A functional film having an antiglare property is provided on the outermost surface of a liquid crystal display, an organic EL display or the like in order to improve the visibility of an image. The antiglare film has a fine concavo-convex structure on the surface, diffuses the surface-reflected light, suppresses regular reflection of external light, and prevents diplomatic reflection.

As a method for forming a functional film having fine irregularities on the surface, a coating liquid containing a binder such as an ultraviolet curable resin and fine particles (filler) is applied onto a translucent substrate to form a coating film. Generally, a method of irradiating the coating film with ultraviolet rays to cure the coating film is used, and the antiglare property and other characteristics can be adjusted by the particle size of the fine particles and the addition amount thereof (see, for example, Patent Documents 1 and 2). ).

JP, 2002-196117, A JP, 2008-158536, A

The conventional antiglare film has a white appearance and a rough texture when it is displayed in black on the display, and has a low-grade appearance.

Therefore, the present invention provides a high-quality optical laminate having an antiglare property, a less rough feeling, and capable of producing a rich and deep black display, and a polarizing plate and an image display device using the same. The purpose is to

The present invention relates to an optical laminate in which at least one optical functional layer is laminated on a translucent substrate, and an uneven shape is formed on at least one surface of the optical functional layer. The transmitted image sharpness using an optical comb having a width of 5 mm is 70 to 95%, and the product of the average area of the convex portions on the outermost surface of the optical functional layer and the arithmetic average height Sa measured by an optical interference method is 4. 7 to 44.0 μm ³ and the average inclination angle θa is 0.124 to 0.349°.

A polarizing plate and an image display device according to the present invention include the above optical laminate.

According to the present invention, it is possible to provide a high-quality optical laminate having an antiglare property, a less rough feeling, and capable of producing a rich and deep black display, and a polarizing plate and an image display device using the same.

Sectional drawing which shows schematic structure of the optical laminated body which concerns on embodiment. Sectional drawing which shows schematic structure of the polarizing plate which concerns on embodiment. Sectional drawing which shows schematic structure of the display apparatus which concerns on embodiment. The graph which plotted the relationship of the product of the average area of a convex part and arithmetic mean height Sa, and the evaluation score of smoothness. Graph plotting the relationship between the average inclination angle and the evaluation score of blackness A graph plotting the relationship between the average area of the protrusions and the product of the arithmetic average height Sa and the average inclination angle.

FIG. 1 is a cross-sectional view showing a schematic configuration of the optical layered body according to the embodiment. The optical layered body 100 according to the embodiment includes a transparent base 1, and at least one optical functional layer 2 laminated on the transparent base 1. Fine irregularities are formed on the surface of the optical function layer 2. The irregularities reflect diplomatically, so that the optical function layer 2 exhibits antiglare properties.

As the translucent substrate, polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate (PC), polyimide (PI), polyethylene (PE), polypropylene Various resin films such as (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), cycloolefin copolymer (COC), norbornene-containing resin, polyether sulfone, cellophane, and aromatic polyamide can be preferably used. ..

The total light transmittance (JIS K7105) of the translucent substrate is preferably 80% or more, more preferably 90% or more. The thickness of the translucent substrate is preferably 1 to 700 μm, more preferably 25 to 250 μm, in consideration of the productivity and handling of the optical laminate.

The translucent substrate is preferably subjected to surface modification treatment in order to improve the adhesion with the optical functional layer. Examples of the surface modification treatment include alkali treatment, corona treatment, plasma treatment, sputtering treatment, application of a surfactant and a silane coupling agent, Si vapor deposition and the like.

The optical functional layer contains a base resin, resin particles, and inorganic fine particles. The optical functional layer is formed by applying a coating liquid containing a base resin that is cured by irradiation with ionizing radiation or ultraviolet rays, resin particles, and inorganic fine particles to a translucent substrate and curing the coating film. It

Hereinafter, constituent components of the resin composition used for forming the optical functional layer will be described.

As the base resin, a resin that is cured by irradiation with ionizing radiation or ultraviolet rays can be used.

As the resin material that is cured by irradiation with ionizing radiation, acryloyl group, methacryloyl group, acryloyloxy group, radical polymerizable functional group such as methacryloyloxy group, and epoxy group, vinyl ether group, cation polymerizable functional group such as oxetane group. The monomers, oligomers and prepolymers can be used alone or as a mixture. Examples of the monomer include methyl acrylate, methyl methacrylate, methoxy polyethylene methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, ethylene glycol dimethacrylate, dipentaerythritol hexaacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate and the like. As the oligomer or prepolymer, polyester acrylate, polyurethane acrylate, polyfunctional urethane acrylate, epoxy acrylate, polyether acrylate, alkoxide acrylate, melamine acrylate, acrylate compounds such as silicone acrylate, unsaturated polyester, tetramethylene glycol diglycidyl ether, Epoxy compounds such as propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether and various alicyclic epoxies, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis{[(3- Examples include oxetane compounds such as ethyl-3-oxetanyl)methoxy]methyl}benzene and di[1-ethyl(3-oxetanyl)]methyl ether.

The resin material described above can be cured by irradiation with ultraviolet rays, provided that a photopolymerization initiator is added. As the photopolymerization initiator, acetophenone-based, benzophenone-based, thioxanthone-based, benzoin, radical polymerization initiators such as benzoin methyl ether, aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, cationic polymerization initiation of metallocene compounds, etc. The agents can be used alone or in combination.

The resin particles added to the optical functional layer aggregate in the base resin to form a fine uneven structure on the surface of the optical functional layer. The resin particles are made of a translucent resin material such as acrylic resin, polystyrene resin, styrene-(meth)acrylic acid ester copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, polyfluorinated ethylene resin You can use one. The refractive index of the material of the resin particles is preferably 1.40 to 1.75. In order to adjust the refractive index and the dispersion of resin particles, two or more kinds of resin particles having different materials (refractive indexes) may be mixed and used.

The average particle size of the resin particles is preferably 0.3 to 10.0 μm, and more preferably 1.0 to 7.0 μm. When the average particle size of the resin particles is less than 0.3 μm, sufficient antiglare property cannot be obtained. On the other hand, when the average particle diameter of the resin particles exceeds 10.0 μm, the product of the average area of the convex portions and the arithmetic average height Sa becomes large, and the graininess becomes strong.

In the optical layered body according to the present embodiment, the content of the resin particles in the solid content of the optical functional layer is 0.1 to 10.0%. When the content of the resin particles is less than 0.1%, the irregularities on the surface of the optical functional layer are reduced and the antiglare property is deteriorated. On the other hand, when the content of the resin particles exceeds 10.0%, the product of the average area of the convex portions and the arithmetic average height Sa becomes large, and the rough feeling becomes strong.

The inorganic fine particles added to the base resin of the optical functional layer are preferably inorganic nanoparticles having an average particle size of 10 to 200 nm. The addition amount of the inorganic fine particles is preferably 0.1 to 5.0%.

As the inorganic fine particles, for example, swelling clay can be used. The swelling clay may be any swelling clay as long as it has a cation exchange ability and swells by taking in a solvent between the layers of the swelling clay. May be. Further, it may be a mixture of a natural product and a synthetic product. Examples of the swelling clay include mica, synthetic mica, vermiculite, montmorillonite, iron montmorillonite, beidellite, saponite, hectorite, stevensite, nontronite, magadiite, ironite, kanemite, layered titanic acid, smectite, synthetic smectite. Etc. can be mentioned. These swelling clays may be used alone or in combination of two or more. Further, colloidal silica, alumina, and zinc oxide may be used alone or in combination as the inorganic fine particles. In addition to the above-mentioned swelling clay, one or more kinds of colloidal silica, alumina and zinc oxide may be used in combination.

Layered organic clay is more preferable as the inorganic fine particles. In the present invention, the layered organic clay refers to a swelling clay into which an organic onium ion is introduced between layers. The organic onium ion is not limited as long as it can be organized by utilizing the cation exchange property of the swelling clay. As the inorganic fine particles, for example, synthetic smectite (layered organic clay mineral) can be used. Synthetic smectite functions as a thickener that increases the viscosity of the resin composition for forming an optical functional layer. Addition of synthetic smectite as a thickener suppresses the sedimentation of resin particles and inorganic fine particles, and contributes to the formation of an uneven structure on the surface of the optical functional layer.

A leveling agent may be added to the resin composition for forming the optical functional layer. The leveling agent has a function of orienting on the surface of the coating film during the drying process to make the surface tension of the coating film uniform and reduce surface defects of the coating film.

Furthermore, an organic solvent may be appropriately added to the resin composition for forming the optical functional layer. Examples of the organic solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, butanol, isopropyl alcohol (IPA) and isobutanol; ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone and methyl isobutyl ketone (MIBK). Ketone alcohols such as diacetone alcohol; aromatic hydrocarbons such as benzene, toluene, xylene; glycols such as ethylene glycol, propylene glycol, hexylene glycol; ethyl cellosolve, butyl cellosolve, ethyl carbitol, Glycol ethers such as butyl carbitol, diethyl cellosolve, diethyl carbitol, propylene glycol monomethyl ether; esters such as N-methylpyrrolidone, dimethylformamide, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, amyl acetate; Ethers such as dimethyl ether and diethyl ether; one kind or a mixture of two or more kinds of water and the like can be used.

The film thickness of the optical function layer is preferably 1.0 to 10.0 μm, and more preferably 3.0 to 7.0 μm. When the film thickness of the optical functional layer is less than 1 μm, curing failure occurs due to oxygen inhibition, and the scratch resistance of the optical functional layer is likely to decrease. On the other hand, if the film thickness of the optical functional layer exceeds 10.0 μm, curling due to curing shrinkage of the base resin layer becomes strong, which is not preferable.

The transmitted image clarity of the optical layered body according to the present embodiment is 70 to 95% when measured using an optical comb having a width of 0.5 mm. When the transmitted image definition is less than 70%, the antiglare property becomes excessive and the visibility deteriorates. On the other hand, when the transmitted image clarity exceeds 95%, sufficient antiglare property cannot be obtained.

In the optical layered body according to the present embodiment, the product of the average area of the convex portions on the outermost surface of the optical function layer and the arithmetic average height Sa measured by the optical interference method is 4.7 to 44.0 μm ³ . Here, the convex portion refers to a portion higher than the average surface when the average surface that passes through the average level of the apexes of all the convex portions and the lowest points of the concave portions existing on the measurement surface is used as a reference, and the convex portion The average area of the part is the average value of the cross-sectional areas of the convex portions at the arithmetic average height Sa. The arithmetic mean height Sa is a value measured according to ISO 25178, and is a parameter obtained by expanding the arithmetic mean roughness Ra in the surface direction. The product of the average area of the convex portions and the arithmetic average height Sa is an approximate value of the average volume of the convex portions existing on the average surface when each convex portion is modeled as a columnar body. The product of the average area of the convex portions and the arithmetic average height Sa is an index representing the size of the convex portions existing on the average surface, and is a parameter that correlates with the smoothness/roughness of the surface of the optical functional layer. Is. When the product of the average area of the convex portions and the arithmetic average height Sa is less than 4.7 μm ³ , the size of the convex portions formed on the surface of the optical functional layer is too small, and sufficient antiglare property cannot be obtained. .. On the other hand, when the product of the average area of the convex portions and the arithmetic average height Sa exceeds 44.0 μm ³ , the size of the convex portions formed on the surface of the optical functional layer is too large, and the graininess becomes strong.

Further, the average inclination angle θa of the uneven shape on the surface of the optical functional layer according to the present embodiment is 0.124 to 0.349°. The average inclination angle is an average value of angles formed by a straight line connecting the apex of the convex portion and the lowest point of the concave portion adjacent to the convex portion with respect to the average surface, and is defined by θa=tan ⁻¹ Δa. Is. Δa is generally measured by measuring the rough surface shape using a stylus type surface roughness meter, and in the roughness curve of the uneven cross section obtained by the measurement, the peak of the convex portion within the reference length L and this It is a value obtained by dividing the sum of the absolute values of the differences from the lowest point of the concave portion adjacent to the convex portion by the reference length L. In the present invention, the conventional value of Δa is expanded in the surface direction to The value was calculated using all the convex portions and concave portions in the measurement surface measured by the interference method. When the average inclination angle θa is less than 0.124°, the size of the convex portion formed on the surface of the optical functional layer is too small, and thus sufficient antiglare properties cannot be obtained. On the other hand, when the average inclination angle θa exceeds 0.349°, whiteness becomes strong when black is displayed on the display.

The inventors of the present invention have confirmed that the transmitted image sharpness, the product of the average area of the convex portions and the arithmetic average height Sa, and the average inclination angle have anti-glare property, smoothness (less roughness) and darkness, respectively. It was newly found that it is a related parameter. As described above, when the value of the transmitted image sharpness is within the specific range, good antiglare property that does not impair the visibility can be obtained. Further, the smaller the product of the average area of the convex portions and the arithmetic average height Sa, the better the smoothness, and the larger the product, the more rough the texture (see FIG. 4 described later). The smaller the average inclination angle is, the stronger the blackness is, and the larger the average inclination angle is, the more the whiteness is increased (see FIG. 5 described later). In the present invention, by selecting the above-mentioned three parameters relating to the antiglare property, smoothness and blackness, the antiglare property is good, the rough feeling is small, and a high-quality optical display capable of producing a deep and dark black display is provided. A laminated body is realized.

Further, it is preferable that a random aggregation structure is formed in the optical function layer. Random aggregation structure, the first phase containing a relatively large amount of resin components, and the second phase containing a relatively large amount of inorganic components are three-dimensionally intricately present, the second phase A structure that is unevenly distributed around fine particles (resin particles). Since the random aggregation structure is formed in the optical function layer, fine irregularities can be reduced, so that the antiglare property and the blackness at the time of black display can be improved. The random aggregation structure can be formed, for example, by the method described in Japanese Patent No. 5802043.

FIG. 2 is a cross-sectional view showing a schematic configuration of the polarizing plate according to the embodiment. The polarizing plate 110 includes the optical layered body 100 and the polarizing film 11. The optical layered body 100 is the one shown in FIG. 1, and a polarizing film (polarizing substrate) 11 is provided on the surface of the transparent substrate 1 on which the optical functional layer 2 is not provided. The polarizing film 11 is, for example, a transparent substrate 3, a polarizing layer 4, and a transparent substrate 5 laminated in this order. The materials of the transparent substrates 3 and 5 and the polarizing layer 4 are not particularly limited, and those normally used for a polarizing film can be appropriately used.

FIG. 3 is a cross-sectional view showing a schematic configuration of the display device according to the embodiment. The display device 120 is formed by laminating the optical laminate 100, the polarizing film 11, the liquid crystal cell 13, the polarizing film (polarizing substrate) 12, and the backlight unit 14 in this order. The polarizing film 12 is formed by laminating a transparent base material 6, a polarizing layer 7, and a transparent base material 8 in this order, for example. The materials of the transparent substrates 6 and 8 and the polarizing layer 7 are not particularly limited, and those normally used for a polarizing film can be appropriately used. The liquid crystal cell 13 includes a liquid crystal panel in which liquid crystal molecules are enclosed between a pair of transparent base materials having transparent electrodes, and a color filter, and changes the orientation of the liquid crystal molecules according to the voltage applied between the transparent electrodes. By doing so, the device controls the light transmittance of each pixel to form an image. The backlight unit 14 is a lighting device that includes a light source and a light diffusing plate (neither is shown), and uniformly diffuses the light emitted from the light source and emits the light from the emission surface.

The display device 120 shown in FIG. 3 may further include a diffusion film, a prism sheet, a brightness enhancement film, a retardation film for compensating the retardation of a liquid crystal cell or a polarizing plate, and a touch sensor.

The optical layered body according to the present embodiment further includes at least one layer of a refractive index adjusting layer such as a low refractive index layer, an antistatic layer, and an antifouling layer, in addition to the optical functional layer that suppresses glare. Is also good.

The low refractive index layer is a functional layer that is provided on the optical functional layer and reduces the reflectance by lowering the refractive index of the surface. The low refractive index layer is formed by applying a coating liquid containing an ionizing radiation curable material such as a polyester acrylate-based monomer, an epoxy acrylate-based monomer, a urethane acrylate-based monomer, and a polyol acrylate-based monomer, and a polymerization initiator, and polymerizing the coating film. It can be formed by curing. In the low refractive index layer, as the low refractive particles, LiF, MgF, 3NaF.AlF or AlF (all have a refractive index of 1.4) or Na ₃ AlF ₆ (cryolite, refractive index of 1.33). It is also possible to disperse low refractive index fine particles made of a low refractive index material such as Further, as the low refractive index fine particles, particles having voids inside can be preferably used. In the case of particles having voids inside the particles, the void portion can be made to have a refractive index of air (≈1), and thus a low refractive index particle having a very low refractive index can be obtained. Specifically, the refractive index can be lowered by using low-refractive index silica particles having voids inside.

The antistatic layer is a coating liquid containing an ionizing radiation curable material such as a polyester acrylate-based monomer, an epoxy acrylate-based monomer, a urethane acrylate-based monomer, and a polyol acrylate-based monomer, a polymerization initiator, and an antistatic agent. It can be formed by curing by polymerization. Examples of the antistatic agent include fine particles of metal oxides such as antimony-doped tin oxide (ATO) and tin-doped indium oxide (ITO), polymer conductive composition, and quaternary ammonium salt. Can be used. The antistatic layer may be provided on the outermost surface of the optical layered body, or may be provided between the optical functional layer and the translucent substrate.

The antifouling layer is provided on the outermost surface of the optical layered body and enhances the antifouling property by imparting water repellency and/or oil repellency to the optical layered body. The antifouling layer can be formed by dry coating or wet coating with a silicon oxide, a fluorine-containing silane compound, a fluoroalkylsilazane, a fluoroalkylsilane, a fluorine-containing silicon compound, a perfluoropolyether group-containing silane coupling agent, or the like. ..

In addition to the low refractive index layer, the antistatic layer, and the antifouling layer described above, or in addition to the low refractive index layer, the antistatic layer, and the antifouling layer, at least an infrared absorbing layer, an ultraviolet absorbing layer, a color correcting layer, and the like. You may provide one layer.

Hereinafter, examples in which the optical layered body according to the embodiment is specifically implemented will be described.

(Method for producing optical laminate)
A coating liquid for forming an optical functional layer was prepared by mixing the materials shown below in the proportions shown in Table 1, and the prepared coating liquid was applied to a 40 μm thick triacetyl cellulose film (translucent substrate). After the coating film was dried (solvent was volatilized), the coating film was irradiated with ultraviolet rays to be photo-cured to obtain optical laminates according to Examples and Comparative Examples. In addition, "-" in Table 1 represents that the corresponding material is not mixed.

[Materials used for coating liquid for forming optical functional layer]
-Base resin: UV/EB curable resin light acrylate PE-3A (pentaerythritol triacrylate, manufactured by Kyoeisha Chemical Co., Ltd.), refractive index 1.52
Resin particles: styrene-methyl methacrylate copolymer particles, refractive index 1.515, average particle size 2.0 μm or 3.5 μm
・Inorganic particles 1: Synthetic smectite ・Inorganic particles 2: Alumina nanoparticles, average particle size 40 nm
Photoinitiator: Irgacure 184 (manufactured by BASF Japan)
-Solvent: A mixed solvent in which toluene and isopropyl alcohol are mixed in a ratio of 16:37

The transmitted image clarity, the average inclination angle, the average area of the convex portions existing on the surface of the optical functional layer, and the arithmetic average height Sa of the optical laminates according to the examples and the comparative examples were measured by the following methods.

[Transmission image clarity]
The transmitted image clarity was measured according to JIS K7105 using an image clarity measuring device (ICM-1T, manufactured by Suga Test Instruments Co., Ltd.) with an optical comb width of 0.5 mm.

[Product of average inclination angle θa, average area of convex portions and arithmetic average height Sa]
The uneven shape of the outermost surface of the optical functional layer is measured using a non-contact surface/layer cross-section shape measurement system (measurement device: Bertscan R3300FL-Lite-AC, analysis software: VertScan4, manufactured by Ryoka Systems Inc.) The measurement data was analyzed by the analysis software of the device. The average tilt angle θa was calculated based on the data of the entire measurement region using the tilt angle analysis function of the analysis software. The average area of the convex portions and the arithmetic average height Sa were calculated using the particle analysis function of the analysis software.

The anti-glare property, film thickness condition, smoothness, and blackness were evaluated according to the following evaluation methods.

[Evaluation method and evaluation criteria for smoothness and darkness]
The optical laminates of Examples and Comparative Examples were attached to a black acrylic plate (SUMIPEX 960 manufactured by Sumitomo Chemical Co., Ltd.) via a transparent adhesive layer to prepare a laminate. The light of a fluorescent lamp was projected on the black acrylic plate, and the surface of the optical laminate was observed from a position vertically separated by 50 cm from the center of the black acrylic plate, and the smoothness and the blackness were evaluated by a sensory evaluation in five levels. The evaluation scores of 20 testers were averaged, and the average value was rounded in 0.5 increments to give an evaluation score. Further, if the evaluation score was 4 or more, it was determined that the smoothness or the blackness was good.
<Evaluation criteria for smoothness>
5: Smooth texture with no graininess 4: Slight texture with little graininess 3: Texture with grainy texture, without smoothness 2: Strong texture with graininess 1: Strong graininess <Evaluation of blackness Criteria>
5: Almost no diffuse reflection on the surface of the optical layered body, rich and moisturized color 4: Little diffused reflection on the surface of the optical layered body, moist color 3: Some diffused reflection on the surface of the optical layered body, and slightly Whiteish tint 2: Slight whiteness 1: Strong whiteness

In Table 1, the composition of the coating liquid for forming the optical functional layer used in Examples and Comparative Examples, the coating thickness of the coating liquid, the transmitted image clarity, the average inclination angle θa, the average area of the convex portions, and the arithmetic average height. The evaluation results of the product of Sa and the smoothness and the darkness are shown together.

The addition ratios of the respective components shown in Tables 1 and 2 are ratios (% by mass) to the total solid mass of the coating liquid for forming an optical functional layer. Here, the total solid content of the coating liquid for forming an optical functional layer refers to the components excluding the solvent. Therefore, the resin particles in the total solid content of the coating liquid for forming an optical functional layer, the compounding ratio (mass %) of the inorganic fine particles, and the resin particles in the optical functional layer that is a cured film of the coating liquid for forming an optical functional layer. , And the content rate (% by mass) of the inorganic fine particles is equal.

FIG. 4 is a graph plotting the relationship between the product of the average area of the convex portions and the arithmetic average height Sa and the evaluation score of smoothness, and FIG. 5 is a graph of the relationship between the average inclination angle and the evaluation score of blackness. This is the graph. In the graphs of FIGS. 4 and 5, the values of all Examples and Comparative Examples shown in Table 1 are plotted.

From FIG. 4, the product of the average area of the convex portions and the arithmetic average height Sa (that is, the approximate value of the volume of the convex portions of the average size) has a negative correlation with the evaluation score of smoothness, and the correlation is extremely high. It turns out to be expensive. Further, it can be seen from FIG. 5 that there is an extremely high negative correlation between the average inclination angle and the evaluation score of blackness.

FIG. 6 is a graph plotting the relationship between the average area of the convex portions and the product of the arithmetic average height Sa and the average inclination angle. In the graph of FIG. 6, black circles are plots of the examples, and x marks are plots of the comparative examples.

When a large number of examples and comparative examples were prepared and examined, as shown in FIG. 6, the optical laminates according to Examples 1 to 13 showed that the product of the average area of the convex portions and the arithmetic average height Sa and the average inclination thereof. It was found that when the corners are within a certain range (the range surrounded by the broken line in FIG. 6), the smoothness and blackness of the surface can be improved. More specifically, when the product of the average area of the convex portions and the arithmetic average height Sa is 4.7 to 44.0 μm ³ and the average inclination angle θa is 0.124 to 0.349°. Thus, it is possible to realize an optical laminated body which is smooth, has no rough feeling, and is rich in moisture and has a deep black display.

As shown in Table 1, in the optical laminated bodies according to Examples 1 to 13, the transmitted image clarity is 70 to 95%, the product of the average area of the convex portions and the arithmetic average height Sa, and the average inclination angle θa. It was confirmed that, since each of the above values is within the above range, it is possible to provide a smooth, moist and deep black display while having antiglare properties.

On the other hand, in Comparative Examples 1 and 7 to 13, since the average tilt angle θa exceeded the upper limit value (0.349°) described above, light was excessively scattered on the surface of the optical functional layer and was whitish. It became an optical laminate with poor quality.

Further, in Comparative Examples 1, 2, 4, 5, 9 and 10, the product of the average area of the convex portions and the arithmetic average height Sa exceeded the upper limit value (44.0 μm ³ ) described above, and therefore, the surface of the optical functional layer. The size of the convex portion formed on the substrate was increased, resulting in an optical laminate having a rough feeling.

In Comparative Example 3, the average inclination angle θa is lower than the lower limit value (0.124°) described above, and the product of the average area of the convex portions and the arithmetic average height Sa is the lower limit value (4.7 μm ^3). 2), the smoothness and the blackness were both highly evaluated, but the size of the convex portion was too small, so that the transmitted image sharpness exceeded 95% and the antiglare property was insufficient. Similarly in Comparative Example 4, since the product of the average area of the convex portions and the arithmetic average height Sa was below the lower limit value (4.7 μm ³ ) described above, the size of the convex portions was too small and the transmitted image clarity was 95%. And the antiglare property was insufficient.

The optical laminate according to the present invention can be used as an antiglare film used in an image display device such as a liquid crystal display or an organic EL display. INDUSTRIAL APPLICABILITY The optical layered body according to the present invention has an antiglare property, has a less rough feeling, and enables a moist deep black display, and thus is suitable as an antiglare film particularly used for a television.

1 Translucent Substrate 2 Optical Functional Layers 3, 5, 6, 8 Transparent Substrates 4, 7 Polarizing Layers 11, 12 Polarizing Plate 13 Liquid Crystal Cell 14 Backlight Unit 100 Optical Laminated Body 110 Polarizing Plate 120 Display Device

Claims (6)

An optical laminate comprising at least one optical functional layer laminated on a translucent substrate,
An uneven shape is formed on at least one surface of the optical functional layer,
The transmitted image clarity using an optical comb having a width of 0.5 mm is 70 to 95%,
The product of the average area of the convex portions on the outermost surface of the optical functional layer and the arithmetic average height Sa measured by an optical interference method is 4.7 to 44.0 μm ³ ,
An optical layered body having an average inclination angle θa of 0.124 to 0.349°. The optical layered body according to claim 1, wherein the optical functional layer forms a random aggregation structure. The optical layered body according to claim 1 or 2, wherein the optical functional layer comprises one or more layers formed of a cured film of a radiation curable resin composition. The optical laminate according to claim 1, further comprising at least one layer of a refractive index adjusting layer, an antistatic layer, and an antifouling layer. A polarizing plate, wherein a polarizing substrate is laminated on the translucent substrate that constitutes the optical laminate according to any one of claims 1 to 4. A display device comprising the optical laminate according to claim 1.

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