Optical laminate, and polarizing plate, surface plate, and image display device comprising the same.

Abstract

The present invention provides an optical laminate that exhibits excellent adhesion between a polyester film with a high degree of surface orientation ΔP and an easy-adhesion layer, without the need for an easy-adhesion layer of a specific material, and that suppresses localized defects. [Solution] An optical laminate 100 having an easy-adhesion layer 20, an uneven layer 30, and an anti-fouling layer 40 on a polyester film 10, wherein when the refractive index in the slow axis direction in the plane of the polyester film is nx, the refractive index in the direction perpendicular to nx is ny, and the refractive index in the thickness direction is nz, the polyester film satisfies the following equations 1-1 and 1-2, and when the three-dimensional skewness of the surface of the uneven layer is defined as Ssk and the three-dimensional arithmetic mean roughness of the surface of the uneven layer is defined as Sa, Ssk and Sa satisfy the following equation 2-1. nx-ny≦0.0250(1-1) 0.140 ≤ ΔP(1-2) 0.80 ≤ A ≤ 1.90 (2-1) ΔP is ((nx+ny) / 2)-nz, A is “log 10 This shows (Sa[μm]×100 / Ssk).

Description

[Technical Field]

[0001] This disclosure relates to an optical laminate, and to a polarizing plate, a surface plate, and an image display device comprising the same. [Background technology]

[0002] Image display devices such as liquid crystal displays, organic EL displays, micro-LED displays, mini-LED displays, and quantum dot displays are equipped with various optical laminates to improve image visibility and suppress scratches on the device surface. Many of these optical laminates consist of functional layers, such as textured layers, on a plastic film. Triacetylcellulose film with low optical anisotropy has been preferably used as the plastic film for the optical laminate. In this specification, "triacetylcellulose film" may be referred to as "TAC film."

[0003] However, TAC film has problems with dimensional stability and mechanical strength, and these problems were particularly pronounced in large-screen image display devices. For this reason, polyester films such as polyethylene terephthalate film have been proposed as alternatives to TAC film. In this specification, "polyethylene terephthalate film" may sometimes be referred to as "PET film."

[0004] However, when PET film is applied to image display devices that output polarized light, such as liquid crystal displays and organic EL displays, the in-plane phase difference of the PET film causes a rainbow-like interference pattern called rainbow unevenness, which reduces visibility. As a countermeasure against rainbow-like unevenness, a method has been proposed to make the in-plane phase difference of the PET film extremely large (for example, Patent Document 1).

[0005] A PET film with an extremely large in-plane phase difference, such as that described in Patent Document 1, can be obtained by uniaxial stretching of a PET film. However, uniaxially stretched films have problems such as being prone to tearing in the stretching direction.

[0006] As a countermeasure against rainbow-like unevenness, contrary to Patent Document 1, a method of reducing the in-plane phase difference of the PET film can be considered. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2011-107198 [Patent Document 2] Japanese Patent Publication No. 2012-32819 [Patent Document 3] Japanese Patent Publication No. 2016-6530 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0008] PET films with small in-plane phase difference can be obtained, for example, by lowering the stretching ratio. However, PET films with a low stretching ratio have a problem in that their mechanical strength decreases due to uneven orientation in the thickness direction, making them impractical.

[0009] Furthermore, examples of PET films with small in-plane phase difference include those described in Patent Documents 2 and 3. The PET films of Patent Documents 2 and 3 have reduced in-plane phase difference compared to general-purpose biaxially oriented PET films, by reducing the difference in stretching ratio between the flow direction (MD direction) and the width direction (TD direction).

[0010] PET films with a reduced in-plane retardation without lowering the draw ratio as in Patent Documents 2 and 3 have the characteristic of a high in-plane orientation degree ΔP. Such a biaxially stretched PET film with a high in-plane orientation degree ΔP has a problem that when a functional layer is provided on the easy-adhesive layer, the interface between the PET film and the easy-adhesive layer is likely to peel off because the adhesion of the easy-adhesive layer is poor. The above problem can be solved by applying an easy-adhesive layer made of a material with excellent adhesion. However, in the above solution, the range of choices of the material of the easy-adhesive layer is limited, which causes restrictions in product design and thus lacks practicality. Also, when performing an optical design of the entire optical laminate, if an easy-adhesive layer of a specific material exists on the PET film, material restrictions on the functional layer formed on the easy-adhesive layer also occur.

[0011] In addition, when a functional layer is formed on a biaxially stretched PET film with a high in-plane orientation degree ΔP via an easy-adhesive layer, local defects may occur in the optical laminate, such as locally different transmittance and reflectance.

[0012] In view of the above problems, an object of the present disclosure is to provide an optical laminate having excellent adhesion between a polyester film with a high in-plane orientation degree ΔP and an easy-adhesive layer and suppressing local defects without using an easy-adhesive layer of a specific material, and a polarizing plate, a surface plate, and an image display device including the same.

Means for Solving the Problems

[0013] In order to solve the above problems, the present disclosure provides the following [1] to [4]. [1] An optical laminate having an easy-adhesive layer, an uneven layer, and an antifouling layer on a polyester film, When the refractive index in the slow axis direction in the plane of the polyester film is nx, the refractive index in the direction orthogonal to the slow axis in the same plane is ny, and the refractive index in the thickness direction of the polyester film is nz, the polyester film satisfies the following formula 1-2, The uneven layer satisfies the following formula 2-1 when the three-dimensional skewness of the surface of the uneven layer is Ssk and the three-dimensional arithmetic mean roughness of the surface of the uneven layer is Sa. 0.140 ≤ ΔP (1-2) 0.80 ≤ A ≤ 1.90 (2-1) [In Formula 1-2, "ΔP" represents "((nx + ny) / 2) - nz".] [In Formula 2-1, "A" represents "log 10 (Sa [μm] × 100 / Ssk)", provided that 0 < Ssk.] [2] A polarizing plate having a polarizer, a first transparent protective plate disposed on one side of the polarizer, and a second transparent protective plate disposed on the other side of the polarizer, wherein at least one of the first transparent protective plate and the second transparent protective plate is the optical laminate described in [1], and the optical laminate is disposed such that the surface on the antifouling layer side faces the opposite side of the polarizer. [3] A surface plate for an image display device obtained by laminating an optical laminate on a resin plate or a glass plate, wherein the optical laminate is the optical laminate described in [1], and the optical laminate is disposed such that the surface on the antifouling layer side faces the opposite side of the resin plate or the glass plate. [4] An image display device in which the optical laminate described in [1] is disposed on a display element such that the surface on the antifouling layer side faces the opposite side of the display element, and the optical laminate is disposed on the surface. [Advantages of the Invention]

[0014] The optical laminate of the present disclosure, as well as the polarizing plate, surface plate, and image display device including the same, can improve the adhesion between a polyester film having a high surface orientation degree ΔP and an easy adhesion layer without using an easy adhesion layer of a specific material, and can suppress local defects of the optical laminate. [Brief Description of the Drawings]

[0015] [Figure 1] It is a cross-sectional view schematically illustrating an embodiment of the optical laminate of the present disclosure. [Modes for Carrying Out the Invention]

[0016] The optical laminate of this disclosure will be described in detail below. In this specification, the numerical range notation "AA~BB" means "AA or higher and BB or lower".

[0017] [Optical laminate] The optical laminate of this disclosure has an easy-adhesion layer, an uneven layer, and an anti-fouling layer on a polyester film. When the refractive index in the slow axis direction within the plane of the polyester film is defined as nx, the refractive index in the direction perpendicular to the slow axis within the same plane as ny, and the refractive index in the thickness direction of the polyester film as nz, the polyester film satisfies the following equations 1-2, The aforementioned uneven layer is such that, when the three-dimensional skewness of the surface of the uneven layer is defined as Ssk and the three-dimensional arithmetic mean roughness of the surface of the uneven layer as Sa, Ssk and Sa satisfy the following equation 2-1. 0.140 ≤ ΔP (1-2) 0.80 ≤ A ≤ 1.90 (2-1) [In equations 1-2, "ΔP" represents "((nx+ny) / 2)-nz".] [In equation 2-1, "A" is "log 10 This represents "(Sa[μm]×100 / Ssk)". However, 0 <Sskである。]

[0018] Figure 1 is a schematic cross-sectional view illustrating one embodiment of the optical laminate of the present disclosure. The optical laminate 100 in Figure 1 has an easy-adhesion layer 20, an uneven layer 30, and an anti-fouling layer 40 on a polyester film 10 in that order.

[0019] <Polyester film> A polyester film must satisfy the following equations 1-2, where nx is defined as the refractive index in the direction of the slow axis within the plane, ny is defined as the refractive index in the direction perpendicular to the slow axis within the same plane, and nz is defined as the refractive index in the thickness direction of the polyester film.

[0020] 0.140 ≤ ΔP (1-2) [In equations 1-2, "ΔP" represents "((nx+ny) / 2)-nz".]

[0021] In this specification, the refractive index, in-plane phase difference, and phase difference in the thickness direction, such as nx, ny, and nz, shall mean the values ​​at a wavelength of 550 nm unless otherwise specified. In this specification, "in-plane phase difference" may be denoted as "Re" and "phase difference in the thickness direction" may be denoted as "Rth".

[0022] 《Formula 1-2》 Equation 1-2 specifies that ΔP, expressed as "((nx+ny) / 2)-nz", must be 0.140 or greater. ΔP is called the degree of surface orientation and is a parameter that indicates the strength of the orientation across the entire surface of the film. If ΔP is less than 0.140, the mechanical strength of the polyester film becomes insufficient, which in turn leads to a decrease in the physical properties of the optical laminate, such as pencil hardness. ΔP is preferably 0.145 or greater, and more preferably 0.150 or greater. However, since curved surface designs are becoming more common in modern image display devices, when considering pencil hardness and flexibility simultaneously, the lower limit of ΔP is preferably 0.160 or greater, and more preferably 0.176 or greater. If ΔP is too large, it may be difficult to make nx-ny less than or equal to 0.0250. For this reason, ΔP is preferably 0.250 or less, more preferably 0.220 or less, and even more preferably 0.200 or less. Embodiments of the ΔP range include 0.140 or more, 0.140 to 0.250, 0.140 to 0.220, 0.140 to 0.200, 0.145 to 0.250, 0.145 to 0.220, 0.145 to 0.200, 0.150 to 0.250, 0.150 to 0.220, 0.150 to 0.200, 0.160 to 0.250, 0.160 to 0.220, 0.160 to 0.200, 0.176 or more, 0.176 to 0.250, 0.176 to 0.220, and 0.176 to 0.200.

[0023] The polyester film of the optical laminate according to this disclosure must satisfy the above formula 1-2. While a polyester film satisfying the above formula 1-2 has the physical properties described above, it has poor adhesion. In the optical laminate according to this disclosure, an easy-adhesion layer and a specific uneven layer are formed in this order on a polyester film satisfying the above formula 1-2, and an anti-fouling layer is formed on the specific uneven layer, thereby improving the adhesion between the polyester film and the easy-adhesion layer, and consequently improving the adhesion of the optical laminate as a whole. The reason why the adhesion of the optical laminate can be improved will be described later.

[0024] The nx, ny, and nz of the polyester film, as well as the in-plane phase difference and thickness-direction phase difference described later, can be measured, for example, using the "RETS-100" product from Otsuka Electronics Co., Ltd.

[0025] In this specification, nx, ny, nz, ΔP, Re, Rth, Sa, Ssk, and A refer to the average values ​​of 14 measurements, excluding the minimum and maximum values ​​of the 16 measurements, unless otherwise specified. Note that "A" is the same as "A" in Equation 2-1. In this specification, it is preferable that the 16 measurement points described above be the intersection points of lines drawn to divide the area inside the outer edge of the measurement sample into five equal parts vertically and horizontally, with a margin of 0.5 cm from the outer edge of the measurement sample. For example, if the measurement sample is a rectangle, a margin of 0.5 cm from the outer edge of the rectangle is used, and measurements are taken at the 16 intersection points of dotted lines that divide the area inside the margin into five equal parts vertically and horizontally. The average value of the 14 points excluding the minimum and maximum values ​​is then taken as the value of each parameter. If the measurement sample is a shape other than a quadrilateral, such as a circle, ellipse, triangle, or pentagon, it is preferable to draw a quadrilateral inscribed within this shape and perform 16 measurements on the said quadrilateral using the method described above.

[0026] In this specification, unless otherwise specified, the atmosphere used for measuring various parameters shall be a temperature of 23°C ± 5°C and a relative humidity of 40% to 65%. Furthermore, unless otherwise specified, the sample shall be exposed to the aforementioned atmosphere for at least 30 minutes before each measurement.

[0027] 《Formula 1-1》 The polyester film preferably satisfies the following formula 1-1. nx-ny≦0.0250 (1-1)

[0028] Equation 1-1 specifies that the difference between the refractive index nx in the slow phase axis direction within the plane of the polyester film and the refractive index ny in the fast phase axis direction, which is perpendicular to the slow phase axis within the same plane, is small. If equation 1-1 is not satisfied and nx-ny exceeds 0.0250, rainbow-like unevenness caused by in-plane phase difference cannot be suppressed. In this specification, unless otherwise specified, "rainbow pattern" refers to a rainbow pattern as seen with the naked eye. Furthermore, if nx-ny exceeds 0.0250, the difference in refractive index of the polyester film increases depending on the viewing direction, which increases the degree to which the reflectivity of the optical laminate varies with direction. When the reflectivity of the optical laminate varies with direction, local defects that occur when condition 2-1 is not met may become more easily recognizable. By setting nx-ny to 0.0250 or less, it is possible to suppress the recognition of local defects.

[0029] nx-ny is more preferably 0.0240 or less, and even more preferably 0.0230 or less. If nx-ny is too small, it is difficult to suppress blackouts. For this reason, nx-ny is preferably 0.0050 or higher, more preferably 0.0080 or higher, and even more preferably 0.0100 or higher. In this specification, "blackout" refers to the phenomenon in which the entire image becomes dark when light that has passed through a polarizer and a polyester film in that order is viewed through polarized sunglasses.

[0030] In the constituent elements shown herein, if multiple options are provided for both the upper and lower limits of a numerical value, one selected from the upper limit options and one selected from the lower limit options can be combined to form an embodiment of the numerical range. For example, in the case of nx-ny, embodiments include numerical ranges of 0.0250 or less, 0.0050 to 0.0250, 0.0050 to 0.0240, 0.0050 to 0.0230, 0.0080 to 0.0250, 0.0080 to 0.0240, 0.0080 to 0.0230, 0.0100 to 0.0250, 0.0100 to 0.0240, and 0.0100 to 0.0230.

[0031] Other physical properties The polyester film preferably has the following physical properties, such as in-plane phase difference and phase difference in the thickness direction. In this specification, the in-plane phase difference and the phase difference in the thickness direction refer to those calculated by the following formulas. In the following formulas, "T" refers to the thickness of the polyester film. In-plane phase difference (Re)=(nx-ny)×T[nm] (1) Phase difference in the thickness direction (Rth) = ((nx + ny) / 2 - nz) × T [nm] (2)

[0032] -In-plane phase difference (Re)- The polyester film preferably has an in-plane phase difference of 1200 nm or less, more preferably 1100 nm or less, more preferably 1000 nm or less, and more preferably 950 nm or less. By keeping the in-plane phase difference below 1200 nm, rainbow-like unevenness can be more easily suppressed.

[0033] The polyester film preferably has an in-plane phase difference of 50 nm or more, more preferably 100 nm or more, more preferably 150 nm or more, more preferably 200 nm or more, more preferably 250 nm or more, more preferably 300 nm or more, and more preferably 400 nm or more. By setting the in-plane phase difference to 50 nm or more, blackout can be more easily suppressed. This is because polyester films with an average in-plane phase difference of less than 50 nm can hardly disturb linearly polarized light and transmit it as is, while polyester films with an average in-plane phase difference of 50 nm or more can disturb linearly polarized light. Furthermore, in order to improve the mechanical strength, such as pencil hardness, of the polyester film, an in-plane phase difference of 520 nm or more is preferable, and 620 nm or more is more preferable.

[0034] Embodiments of the in-plane phase difference range for polyester films include: 50nm to 1200nm, 50nm to 1100nm, 50nm to 1000nm, 50nm to 950nm, 100nm to 1200nm, 100nm to 1100nm, 100nm to 1000nm, 100nm to 950nm, 150nm to 1200nm, 150nm to 1100nm, 150nm to 1000nm, 150nm to 950nm, 200nm to 1200nm, 200nm to 1100nm, 200nm to 1000nm, 200nm to 950nm, 250nm to 1200nm, and 250nm or less. Examples include below 1100nm, between 250nm and 1000nm, between 250nm and 950nm, between 300nm and 1200nm, between 300nm and 1100nm, between 300nm and 1000nm, between 300nm and 950nm, between 400nm and 1200nm, between 400nm and 1100nm, between 400nm and 1000nm, between 400nm and 950nm, between 520nm and 1200nm, between 520nm and 1100nm, between 520nm and 1000nm, between 520nm and 950nm, between 620nm and 1200nm, between 620nm and 1100nm, between 620nm and 1000nm, and between 620nm and 950nm.

[0035] -Phase difference in the thickness direction (Rth)- The polyester film preferably has a phase difference in the thickness direction of 2000 nm or more, more preferably 3000 nm or more, even more preferably 4000 nm or more, and even more preferably 5000 nm or more. By setting the phase difference in the thickness direction of the polyester film to 2000 nm or more, it becomes easier to suppress blackout not only when viewed from the front but also when viewed from an oblique direction. The phase difference in the thickness direction of the polyester film is preferably 15,000 nm or less, more preferably 12,000 nm or less, and even more preferably 9,000 nm or less, in order to facilitate the Re / Rth being within the range described later. Examples of the in-plane phase difference range for polyester films include 2000nm to 15000nm, 2000nm to 12000nm, 2000nm to 9000nm, 3000nm to 15000nm, 3000nm to 12000nm, 3000nm to 9000nm, 4000nm to 15000nm, 4000nm to 12000nm, 4000nm to 9000nm, 5000nm to 15000nm, 5000nm to 12000nm, and 5000nm to 9000nm.

[0036] -Re / Rth- The polyester film preferably has a Re / Rth of 0.20 or less, more preferably 0.17 or less, and even more preferably 0.15 or less. A small Re / Rth ratio means that the degree of stretching of the polyester film approaches a uniform biaxial shape. Therefore, by setting the ratio to 0.20 or less, the mechanical strength of the polyester film can be improved, and wrinkles that form in the polyester film due to environmental changes and negatively affect visibility can be suppressed. To easily obtain the above-mentioned effects, it is preferable that the in-plane phase difference of the polyester film is within the above range. The lower limit of Re / Rth is usually around 0.01. Embodiments of the Re / Rth range include 0.01 to 0.20, 0.01 to 0.17, and 0.01 to 0.15.

[0037] -Haze, total light transmittance- The polyester film preferably has a haze of 3.0% or less, more preferably 2.0% or less, and even more preferably 1.0% or less, according to JIS K7136:2000. Furthermore, the polyester film preferably has a total light transmittance of 80% or more, more preferably 85% or more, and even more preferably 90% or more, according to JIS K7361-1:1997.

[0038] -UV transmittance- The polyester film preferably has a light transmittance of 20% or less at a wavelength of 380 nm, and more preferably 10% or less.

[0039] -Thickness- The thickness of the polyester film is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 25 μm or more, and even more preferably 30 μm or more, in order to obtain good mechanical strength. Furthermore, a thickness of 10 μm or more for the polyester film is preferable because, when other components come into contact with the polyester film side of the optical laminate and stress is generated, the stress is less likely to be transmitted to the interface between the polyester film and the easy-adhesion layer. Furthermore, the thickness of the polyester film is preferably 75 μm or less, more preferably 60 μm or less, even more preferably 55 μm or less, and even more preferably 50 μm or less, in order to reduce the in-plane phase difference and to improve flexibility.

[0040] Embodiments of the thickness range of the plastic film include 10 μm to 75 μm, 10 μm to 60 μm, 10 μm to 55 μm, 10 μm to 50 μm, 20 μm to 75 μm, 20 μm to 60 μm, 20 μm to 55 μm, 20 μm to 50 μm, 25 μm to 75 μm, 25 μm to 60 μm, 25 μm to 55 μm, 25 μm to 50 μm, 30 μm to 75 μm, 30 μm to 60 μm, 30 μm to 55 μm, and 30 μm to 50 μm.

[0041] -Stretching- In order to easily satisfy equations 1-1 and 1-2, it is preferable to keep the stretching ratios in the longitudinal and transverse directions from decreasing, and to bring the stretching ratios in both directions closer together. Therefore, the polyester film is preferably a stretched film, and more preferably a biaxially oriented film. The specific conditions for extension will be discussed later.

[0042] 《Raw materials》 Polyesters constituting the polyester film include homopolymers obtained from the polycondensation of dicarboxylic acids and diols; copolymers obtained from the polycondensation of one or more dicarboxylic acids and two or more diols; copolymers obtained from the polycondensation of two or more dicarboxylic acids and one or more diols; and blended resins obtained by mixing one or more homopolymers and one or more copolymers. The polyester film may contain additives such as ultraviolet absorbers, slippery particles such as inorganic particles, heat-resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, light-resistant agents, flame retardants, heat stabilizers, antioxidants, gelation inhibitors, and surfactants, to the extent that they do not impair the effects of the present disclosure.

[0043] Examples of dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedilcarboxylic acid, diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfoncarboxylic acid, anthracenedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, azelaic acid, dimeric acid, sebacic acid, suberic acid, and dodecanedicarboxylic acid. Examples of diols include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone.

[0044] Among polyesters, polyethylene terephthalate is preferred for its good mechanical strength. In other words, polyester films preferably contain polyethylene terephthalate.

[0045] Polymerization methods for polyethylene terephthalate include direct polymerization, in which terephthalic acid is directly reacted with ethylene glycol and, optionally, other dicarboxylic acid and diol components; and transesterification, in which dimethyl ester of terephthalic acid is transesterified with ethylene glycol. In transesterification, dimethyl ester of terephthalic acid may optionally contain methyl esters of other dicarboxylic acids. In transesterification, ethylene glycol may optionally contain other diol components.

[0046] The intrinsic viscosity of polyethylene terephthalate is preferably between 0.45 and 0.70. If the intrinsic viscosity is lower than 0.45, the effect of improving tear resistance decreases, and if the intrinsic viscosity is higher than 0.70, the increase in filtration pressure becomes large, making high-precision filtration difficult.

[0047] 《Layer composition》 The polyester film may have a single-layer or multi-layer structure. A single-layer structure is easy to control in terms of stretching. Equations 1-1 and 1-2 can be easily satisfied by bringing the stretching ratios in the longitudinal and transverse directions closer together without reducing them. For this reason, a single-layer structure, which is easy to control in terms of stretching, is preferred because it easily satisfies equations 1-1 and 1-2. On the other hand, multilayer polyester films are preferable in that they can be enhanced by, for example, changing the composition of each layer. For example, by co-extruding a laminated polyester film consisting of at least three layers, and using a polyester with a low oligomer content in the surface layer, it is possible to suppress the amount of oligomer precipitation on the film surface after heat treatment.

[0048] When a multilayer polyester film is used, the thickness of the surface layer is preferably 3 μm or more, more preferably 5 μm or more, on one side only, and is 25% or less of the total thickness, even more preferably 20% or less, and particularly preferably 10% or less.

[0049] Examples of polyester film manufacturing An embodiment of a method for manufacturing polyester film will be described using PET film as an example. First, PET pellets are thoroughly vacuum-dried. After feeding the vacuum-dried PET pellets into an extruder, they are melt-extruded into a sheet at a temperature of 260°C to 290°C, and then cooled and solidified to produce an unstretched PET sheet. At this time, high-precision filtration is performed in any location where the molten resin is maintained at a temperature of 260°C to 290°C to remove foreign matter contained in the resin. The filter material used for high-precision filtration of the molten resin is not particularly limited, but stainless steel sintered filter material is preferred. Stainless steel sintered filter material has excellent performance in removing aggregates mainly composed of Si, Ti, Sb, Ge, and Cu, as well as high-melting-point organic matter. Furthermore, the filtration particle size of the filter material is preferably 15 μm or less. The aforementioned filtration particle size is the value at an initial filtration efficiency of 95%.

[0050] In the extrusion method, PET is melted and extruded from an extrusion die, and then cooled and solidified with a cooling roll to obtain an unstretched sheet. If necessary, polyester resin layers may be laminated using two or three extruders, a two- or three-layer multi-manifold, or a feed block. To improve the sheet's flatness, it is preferable to use an electrostatic application adhesion method or a liquid coating adhesion method to enhance the adhesion between the sheet and the rotating cooling drum.

[0051] The unstretched film obtained as described above is stretched longitudinally on a roll heated to 70°C to 120°C to obtain a uniaxially oriented PET film. If it is desired to reduce the distortion of the orientation axis due to the so-called bowing phenomenon, a method of lowering the stretching ratio in the longitudinal direction within a range where thickness variations are not a problem, or a method of setting the stretching temperature higher may be adopted. Furthermore, the surface temperature at the start of stretching is preferably between 80°C and 93°C. Within this temperature range, orientation and crystallization do not progress too much in the initial stages of stretching, thus allowing for a desirable ΔP.

[0052] Next, the film is held at both ends with clips and guided into a hot air zone heated to 70°C to 200°C. After drying, it is stretched in the width direction. Subsequently, it is guided into a heat treatment zone within the heat-fixing temperature range described later, and heat treatment is performed to complete the crystal orientation. During this heat treatment process, a relaxation treatment of 2% to 10% in the width direction or longitudinal direction may be applied as needed. Furthermore, PET film may be manufactured using simultaneous biaxial stretching instead of sequential biaxial stretching as described above.

[0053] The stretching ratio during film stretching is preferably 2 times or more and 6.5 times or less in both the longitudinal and width directions, more preferably 2.5 times or more and 5.5 times or less, and even more preferably 3 times or more and 4.8 times or less. By setting the film stretching ratio to 2 times or more, it becomes easier to satisfy equation 1-2. Furthermore, by setting the film stretching ratio to 6.5 times or less, it becomes easier to suppress ΔP from becoming too large, and also easier to suppress wrinkles and cracks during film formation.

[0054] The ratio of the stretching ratio in the longitudinal direction to the stretching ratio in the width direction, known as "stretching ratio in the longitudinal direction / stretching ratio in the width direction," is preferably 1.7 or less, and more preferably 1.4 or less. Furthermore, the ratio is preferably 0.5 or more, more preferably 0.7 or more, and even more preferably 1.0 or more. By setting the ratio of the elongation ratio in the longitudinal direction to the elongation ratio in the width direction within the above range, it becomes easier to satisfy equation 1-1. Furthermore, when sequential stretching is employed, the orientation of the film tends to be strongly influenced by the stretching direction of the final stage. For this reason, in sequential stretching, it is preferable to make the stretching ratio in the longitudinal direction higher than the stretching ratio in the width direction.

[0055] Furthermore, when sequential stretching is employed, it is preferable to perform the stretching in the width direction in at least two stages. In particular, it is preferable to perform the stretching in the width direction in two or more sections with different stretching temperatures. In this case, it is preferable that the stretching temperature of the later stage be 5°C or more, more preferably 10°C or more, higher than the stretching temperature of the earlier stage. The high-temperature later stretching process can mitigate the distortion of optical properties caused by bowing in the width direction in the earlier stage, thereby suppressing fluctuations in the in-plane phase difference in the width direction. Also, when performing width stretching in two stages, it is preferable to lower the stretching ratio of the later stage than the stretching ratio of the earlier stage. Lowering the stretching ratio of the later stage can suppress the deterioration of thickness unevenness in the film. Specifically, when performing width stretching in two stages, it is preferable to perform the first stage stretching at a range of 120°C to 200°C with a ratio of 1.5 to 4.5 times, and then further stretch at a ratio of 1.01 to 2.0 times at a temperature of 150°C to 230°C. The following explanation uses the example of performing the first stage of stretching in the range of 120°C to 200°C and the second stage of stretching in the range of 150°C to 230°C. The first stage of stretching may be referred to as TD1, and the second stage as TD2.

[0056] When performing two-stage stretching within the above range, the stretching temperature of TD1 is preferably 120°C to 200°C, and more preferably 130°C to 150°C. Below 120°C, the film will break, and above 200°C, the distortion of the film's physical properties in the width direction will increase. The stretching ratio is preferably 1.5 to 4.5 times. Furthermore, the stretching temperature of TD2 is preferably 150°C to 230°C, and more preferably 180°C to 220°C. The stretching ratio is preferably 1.01 to 2.0 times. In this way, by performing both stages of stretching within a temperature range of 120°C to 230°C, and further setting the combined stretching ratio of the two stages to 3.0 to 4.8 times, it is possible to reduce fluctuations in the in-plane phase difference in the width direction while maintaining surface orientation that can preserve mechanical strength.

[0057] To improve the thermal dimensional stability of the film, it is preferable to perform thermal fixing at a high temperature. Specifically, the upper limit of the thermal fixing temperature is preferably above 130°C, and more preferably above 160°C. However, performing thermal fixing at a high temperature can easily lead to optical distortion due to bowing, which may result in large fluctuations in the in-plane phase difference. Therefore, it is preferable that the upper limit of the thermal fixing temperature be 220°C or lower.

[0058] <Easy adhesion layer> The optical laminate of this disclosure requires having an easy-adhesion layer between the polyester film and the uneven layer. If an easy-adhesion layer is not present, even if the uneven layer and anti-fouling layer described later are present, it is not possible to achieve good adhesion for the entire optical laminate.

[0059] The resin constituting the easy-adhesion layer is not particularly limited, and examples include thermoplastic resins such as polyester resin, polyurethane resin, and acrylic resin, as well as thermosetting resins, with thermoplastic resins being preferred. Among thermoplastic resins, polyester resin and polyurethane resin are preferred because they can easily reduce the refractive index difference between the polyester film and the easy-adhesion layer, and between the easy-adhesion layer and the uneven layer, and polyester urethane resin is more preferred.

[0060] The resin constituting the easy-adhesion layer preferably has a number average molecular weight of 10,000 or more, and more preferably 20,000 or more. The same resin preferably has a number average molecular weight of 100,000 or less, and more preferably 60,000 or less. By setting the number average molecular weight of the resin constituting the easy-adhesion layer within the above range, it is possible to suppress cohesive failure of the easy-adhesion layer. Preferred ranges for the number-average molecular weight of the resin constituting the easy-adhesion layer include 10,000 to 100,000, 10,000 to 60,000, 20,000 to 100,000, and 20,000 to 60,000.

[0061] The resin constituting the easy-adhesion layer preferably has a glass transition temperature of 30°C or higher, more preferably 50°C or higher, and even more preferably 70°C or higher. The same resin preferably has a glass transition temperature of 120°C or lower, more preferably 110°C or lower, and even more preferably 90°C or lower. By setting the glass transition temperature of the resin constituting the easy-adhesion layer within the above range, it is possible to suppress the embrittlement of the easy-adhesion layer due to heat during the manufacturing process. Examples of heat during the manufacturing process include heat generated during the drying process of the coating liquid for the uneven layer and the coating liquid for the anti-fouling layer, and heat generated by heating when bonding the optical laminate to the polarizer. Preferred ranges for the glass transition temperature of the resin constituting the easy-adhesion layer include 30°C to 120°C, 30°C to 110°C, 30°C to 90°C, 50°C to 120°C, 50°C to 110°C, 50°C to 90°C, 70°C to 120°C, 70°C to 110°C, and 70°C to 90°C.

[0062] The easy-adhesion layer may contain additives such as refractive index modifiers, dyes, pigments, leveling agents, ultraviolet absorbers, antioxidants, and light stabilizers, to the extent that they do not impair the effects of the present disclosure; and various crosslinking agents for adjusting hardness and viscosity. Examples of such crosslinking agents include non-yellowing XDI-based, IPDI-based, and HDI-based isocyanates, and ionizing radiation-curable polyfunctional monomers.

[0063] The easy-adhesion layer may be formed by an in-line coating method, in which it is applied during the formation of the polyester film, or by an off-line coating method, in which it is applied after the formation of the polyester film. The dry application amount of the easy-adhesion layer is 0.05 g / m². 2 More than 0.75g / m 2 The following is preferable. The thickness of the easy-adhesion layer is not particularly limited, but it is preferably 10 nm to 600 nm. When a polyester film, easy-adhesion layer, textured layer, and anti-fouling layer are laminated, in order to prevent poor visibility caused by refractive index differences at each interface, the thickness of the easy-adhesion layer is preferably 10 nm to 40 nm, or 70 nm to 270 nm.

[0064] <Uneven layer> The optical laminate of this disclosure has a textured layer on an easily bondable layer.

[0065] 《Formula 2-1》 The uneven layer must satisfy the following equation 2-1, where Ssk is defined as the three-dimensional skewness of the surface of the uneven layer and Sa is defined as the three-dimensional arithmetic mean roughness of the surface of the uneven layer.

[0066] 0.80 ≤ A ≤ 1.90 (2-1) [In equation 2-1, "A" is "log 10 This represents "(Sa[μm]×100 / Ssk)". However, 0 <Sskである。]

[0067] In this specification, Ssk is a three-dimensional extension of the skewness Rsk of the roughness curve, a two-dimensional roughness parameter described in JIS B0601:1994. It is calculated using the following formula a, assuming orthogonal coordinate axes X and Y are placed on a reference plane, the measured surface shape curve is denoted as z=f(x,y), and the dimensions of the reference plane are Lx and Ly. Ssk is defined in ISO 25178:2012. Ssk is an index that indicates the degree of bias in the positive and negative directions of the elevation distribution, relative to the average elevation of the entire measurement surface. If the elevation distribution follows a normal distribution, Ssk will be 0. If the elevation distribution is biased in the negative direction, Ssk will be a positive value, and the greater the degree of negative bias, the larger the Ssk value will be in the positive direction. Conversely, if the elevation distribution is biased in the positive direction, Ssk will be a negative value, and the greater the degree of positive bias, the larger the Ssk value will be in the negative direction.

[0068]

number

[0069]

number

[0070] In this specification, Sa is a three-dimensional extension of the arithmetic mean roughness Ra of the two-dimensional roughness parameter described in JIS B0601:1994. When the X and Y axes of the Cartesian coordinate system are placed on the reference plane and the roughness surface is denoted as Z(x,y), Sa is calculated using the following formula c. Sa is defined in ISO 25178:2012.

[0071]

number

[0072] In equation 2-1, "A" is "log 10 This is represented by "(Sa[μm]×100 / Ssk)". Therefore, it can be said that "A" in equation 2-1 will have an extremely small value in any of the following cases x-1 to x3. x-1: When Sa is too small. x-2: When Ssk is too large. x-3: When Sa is moderately small and Ssk is moderately large.

[0073] When the Sa of the uneven layer is too small, as in x-1, the unevenness of the uneven layer is hardly reflected on the surface of the antifouling layer, and the surface of the optical laminate, which is the surface of the antifouling layer, becomes almost smooth. When another component comes into contact with the optical laminate with an almost smooth surface shape, stress is applied in such a way that the other component adheres to the surface of the optical laminate, and this stress is transmitted to the interface between the polyester film and the easy-adhesion layer with almost no reduction. For this reason, when the Sa of the uneven layer is too small, as in x-1, it may not be possible to achieve good adhesion at the interface between the polyester film and the easy-adhesion layer. Furthermore, if the Ssk of the uneven layer is too large, as in x-2, the proportion of the uneven layer consisting of sea areas with lower elevations than average becomes extremely large. As a result, the surface of the optical laminate, which is the surface of the antifouling layer, has a shape with an extremely high proportion of sea areas. When other components come into contact with an optical laminate with a surface shape that has an extremely large proportion of sea areas, stress is applied in a way that causes the other components to stick to the sea areas of the optical laminate, and the stress is transmitted to the interface between the polyester film and the easy-adhesion layer with almost no reduction. For this reason, if the Ssk of the uneven layer is too large, as in x-2, it may not be possible to achieve good adhesion at the interface between the polyester film and the easy-adhesion layer. In addition, when an antifouling layer is formed on an uneven layer with an excessively large Ssk, the antifouling layer is sufficiently formed in the areas corresponding to the sea areas of the uneven layer, while it is difficult to form the antifouling layer in the areas corresponding to the islands of the uneven layer, resulting in uneven thickness of the antifouling layer. As a result, bright spots and other defects may occur in the optical laminate due to differences in transmittance or reflectance between the areas corresponding to the sea areas and the areas corresponding to the islands. Furthermore, when Sa is moderately small and Ssk is moderately large, as in x-3, the surface shape has a small degree of unevenness, and the proportion of sea areas is moderately high compared to island areas. When another component comes into contact with an optical laminate with such a surface shape, stress is applied in such a way that the other component adheres to the sea areas of the optical laminate. As a result, the stress is transmitted to the interface between the polyester film and the easy-adhesion layer with almost no reduction. Therefore, when Sa is moderately small and Ssk is moderately large, as in x-3, it may not be possible to achieve good adhesion at the interface between the polyester film and the easy-adhesion layer.

[0074] Furthermore, it can be said that "A" in Equation 2-1 will show an extremely large value in any of the following cases y-1 to y3. y-1: When Sa is too large. y-2: When Ssk is too small. y-3: When Sa is moderately large and Ssk is moderately small.

[0075] When the Sa of the uneven layer is too large, as in y-1, the antifouling layer is sufficiently formed in the areas corresponding to the sea portion of the uneven layer, while it is difficult to form the antifouling layer in the areas corresponding to the islands, resulting in uneven thickness of the antifouling layer. As a result, differences in transmittance or reflectance between the areas corresponding to the sea portion and the areas corresponding to the islands may cause bright spots, which can lead to localized defects in the optical laminate. Furthermore, if the Ssk of the uneven layer is too small, as in y-2, the ratio of island areas to sea areas in the uneven layer approaches 1:1, and consequently, the ratio of island areas to sea areas on the surface of the optical laminate approaches 1:1. Island areas are more likely to come into contact with other components than sea areas, and therefore more likely to adhere to them. For this reason, when other components come into contact with an optical laminate with a surface shape where the Ssk of the uneven layer is too small, as in y-2, stress is applied in such a way that the other components adhere to the island areas of the optical laminate. As a result, this stress is transmitted to the interface between the polyester film and the easy-adhesion layer with almost no reduction. Therefore, if the Ssk of the uneven layer is too small, as in y-2, it may not be possible to achieve good adhesion at the interface between the polyester film and the easy-adhesion layer. Furthermore, when Sa is moderately large and Ssk is moderately small, as in y-3, the surface shape has moderately large irregularities, and the proportion of sea areas is not too high compared to island areas. Although optical laminates with such a surface shape are less prone to adhesion problems, the antifouling layer is sufficiently formed in the areas corresponding to the sea areas of the irregular layer, while it is difficult to form the antifouling layer in the areas corresponding to the island areas of the irregular layer, resulting in uneven thickness of the antifouling layer. As a result, bright spots and other defects may occur in the optical laminate due to differences in transmittance or reflectance between the areas corresponding to the sea areas and the areas corresponding to the island areas.

[0076] From the above, if Equation 2-1 is not satisfied, good adhesion at the interface between the polyester film and the easy-adhesion layer cannot be achieved. Furthermore, if Equation 2-1 is not satisfied, thickness variations occur in the anti-fouling layer, leading to localized problems such as bright spots due to differences in transmittance or reflectance. In other words, if Equation 2-1 is not satisfied, the problem of localized defects in the optical laminate cannot be suppressed.

[0077] In formula 2-1, A is preferably 0.90 or higher, more preferably 0.95 or higher, and even more preferably 1.00 or higher. Also, in formula 2-1, A is preferably 1.75 or lower, more preferably 1.65 or lower, and even more preferably 1.60 or lower. Embodiments of the range A in Equation 2-1 include 0.80 to 1.90, 0.80 to 1.75, 0.80 to 1.65, 0.80 to 1.60, 0.90 to 1.90, 0.90 to 1.75, 0.90 to 1.65, 0.90 to 1.60, 0.95 to 1.90, 0.95 to 1.75, 0.95 to 1.65, 0.95 to 1.60, 1.00 to 1.90, 1.00 to 1.75, 1.00 to 1.65, and 1.00 to 1.60.

[0078] In this specification, Ssk and Sa measurements are assumed to have been performed in a 0.26 mm square area (Lx and Ly in formulas a-c above are 0.26 mm). The vertical and horizontal lengths of the areas where Ssk and Sa are measured do not need to be perfectly identical, and slight differences are acceptable. In the example, the measurement area is 258 μm × 259 μm. Furthermore, in this specification, Ssk and Sa refer to values ​​measured without setting a cutoff value. Ssk and Sa can be measured, for example, with a laser microscope-type surface profile measuring instrument. An example of a laser microscope-type surface profile measuring instrument is the "LEXT OLS4000" from Olympus Corporation.

[0079] 《Formula 2-2》 For the uneven layer, it is preferable that Ssk satisfies the following equation 2-2. 0.10 ≤ Ssk ≤ 1.50 (2-2)

[0080] By setting Ssk to between 0.10 and 1.50, it becomes easier to satisfy equation 2-1. Ssk is more preferably 0.12 or higher, and even more preferably 0.15 or higher. Furthermore, Ssk is more preferably 1.00 or lower, more preferably 0.90 or lower, more preferably 0.70 or lower, and even more preferably 0.55 or lower. Embodiments of the range of Sazz include 0.10 to 1.50, 0.10 to 1.00, 0.10 to 0.90, 0.10 to 0.70, 0.10 to 0.55, 0.12 to 1.50, 0.12 to 1.00, 0.12 to 0.90, 0.12 to 0.70, 0.12 to 0.55, 0.15 to 1.50, 0.15 to 1.00, 0.15 to 0.90, 0.15 to 0.70, and 0.15 to 0.55.

[0081] 《Formula 2-3》 The uneven layer is preferably such that Sa satisfies the following equations 2-3. 0.020μm≦Sa≦0.200μm (2-3)

[0082] By setting Sa to between 0.020 μm and 0.200 μm, it becomes easier to satisfy equation 2-1. Sa is more preferably 0.030 μm or larger, and even more preferably 0.040 μm or larger. Furthermore, Sa is more preferably 0.150 μm or smaller, even more preferably 0.100 μm or smaller, and even more preferably 0.085 μm or smaller. Embodiments of the range of Sa include 0.020 μm to 0.200 μm, 0.020 μm to 0.150 μm, 0.020 μm to 0.100 μm, 0.020 μm to 0.085 μm, 0.030 μm to 0.200 μm, 0.030 μm to 0.150 μm, 0.030 μm to 0.100 μm, 0.030 μm to 0.085 μm, 0.040 μm to 0.200 μm, 0.040 μm to 0.150 μm, 0.040 μm to 0.100 μm, and 0.040 μm to 0.085 μm.

[0083] The uneven layer preferably contains a binder resin and particles.

[0084] Binder resin The binder resin preferably contains a cured product of a curable resin composition. Examples of cured products of curable resin compositions include cured products of thermosetting resin compositions and cured products of ionizing radiation-curable resin compositions, and cured products of ionizing radiation-curable resin compositions are preferred in order to improve mechanical strength.

[0085] The ratio of the cured product of the curable resin composition to the total binder resin of the uneven layer is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 100% by mass.

[0086] A thermosetting resin composition is a composition containing at least a thermosetting resin, and is a resin composition that hardens upon heating. Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. A curing agent is added to these thermosetting resin compositions as needed.

[0087] An ionizing radiation-curable resin composition is a composition containing a compound having an ionizing radiation-curable functional group. In this specification, a "compound having an ionizing radiation-curable functional group" may be referred to as an "ionizing radiation-curable compound." Ionizing radiation refers to electromagnetic waves or charged particle beams that possess energy quanta capable of polymerizing or bridging molecules. While ultraviolet rays or electron beams are commonly used, other electromagnetic waves such as X-rays and gamma rays, as well as charged particle beams such as alpha rays and ion beams, can also be used.

[0088] Examples of ionizing radiation-curable functional groups include ethylenically unsaturated bonding groups such as (meth)acryloyl groups, vinyl groups, and allyl groups, as well as epoxy groups and oxetanyl groups. As ionizing radiation-curable compounds, compounds having ethylenically unsaturated bonding groups are preferred, compounds having two or more ethylenically unsaturated bonding groups are more preferred, and among these, polyfunctional (meth)acrylate compounds having two or more ethylenically unsaturated bonding groups are even more preferred.

[0089] As the polyfunctional (meth)acrylate compound, either monomers or oligomers can be used, but it is preferable that they include oligomers. That is, it is preferable that the uneven layer contains a cured product of a polyfunctional (meth)acrylate oligomer as a binder resin. The cured product of a polyfunctional (meth)acrylate oligomer can improve the surface hardness of the optical laminate while suppressing excessive curing shrinkage of the uneven layer, thus preventing the elevation difference of the unevenness of the uneven layer containing particles from becoming excessive. For this reason, by including a cured product of a polyfunctional (meth)acrylate oligomer in the uneven layer, it is easier to suppress the excessive increase of Ssk and Sa. On the other hand, since oligomers have a higher viscosity than monomers, the leveling properties of the coating liquid for the uneven layer may decrease, and the Ssk may increase. For this reason, it is more preferable for the polyfunctional (meth)acrylate compound to contain both oligomers and monomers. In other words, it is preferable for the uneven layer to contain a cured product of a polyfunctional (meth)acrylate oligomer and a cured product of a polyfunctional (meth)acrylate monomer as the binder resin.

[0090] When using oligomers and monomers as polyfunctional (meth)acrylate compounds, the mass ratio of oligomer to monomer is preferably 20:80 to 80:20, more preferably 20:80 to 60:40 or 40:60 to 80:20, and even more preferably 40:60 to 60:40.

[0091] Examples of polyfunctional (meth)acrylate oligomers include (meth)acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate. Urethane (meth)acrylates can be obtained, for example, by the reaction of polyhydric alcohols and organic diisocyanates with hydroxy(meth)acrylates.

[0092] The weight-average molecular weight of the polyfunctional (meth)acrylate oligomer is preferably 500 or more at the lower limit, more preferably 1000 or more, and preferably 5000 or less at the upper limit, and more preferably 3000 or less. By setting the weight-average molecular weight of the oligomer to 500 or higher, excessive curing shrinkage of the uneven layer can be more easily suppressed. Furthermore, by setting the weight-average molecular weight of the oligomer to 5000 or lower, it is easier to suppress the decrease in the leveling properties of the coating solution for the uneven layer, which can lead to an excessively large Ssk. Examples of weight-average molecular weight ranges for functional (meth)acrylate oligomers include 500 to 5000, 500 to 3000, 1000 to 5000, and 1000 to 3000. In this specification, weight-average molecular weight and number-average molecular weight refer to polystyrene-equivalent values ​​measured by gel permeation chromatography.

[0093] Among the polyfunctional (meth)acrylate compounds, examples of difunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiaacrylate, bisphenol A tetrapropoxydiaacrylate, and 1,6-hexanediol diacrylate. Examples of (meth)acrylate monomers with three or more functionalities include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate. The above (meth)acrylate monomers may also have a modified molecular skeleton. For example, (meth)acrylate monomers modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, etc., can also be used.

[0094] Furthermore, monofunctional (meth)acrylate may be added as an ionizing radiation-curable compound for purposes such as adjusting the viscosity of the coating solution for the uneven layer. Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate. The above-mentioned ionizing radiation-curable compounds can be used individually or in combination of two or more. Furthermore, in addition to the ionizing radiation-curable compound, a polymer may be added to the coating solution for the uneven layer to adjust its viscosity. Examples of polymers include those with a weight-average molecular weight of over 5,000 and up to 200,000.

[0095] When the ionizing radiation-curable compound is an ultraviolet-curable compound, the ionizing radiation-curable composition preferably contains additives such as photopolymerization initiators and photopolymerization accelerators. Examples of photopolymerization initiators include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler ketone, benzoin, benzyldimethyl ketal, benzoyl benzoate, α-acyloxime ester, anthraquinone, halogenoketone, thioxanthone, etc. Among these, α-hydroxyalkylphenone, which is less prone to yellowing, is preferred. Photopolymerization accelerators are those that can reduce polymerization inhibition by air during curing and accelerate the curing speed, and examples include one or more selected from p-dimethylaminobenzoate isoamyl ester, p-dimethylaminobenzoate ethyl ester, etc.

[0096] "particle" Examples of particles include organic particles, inorganic particles, and metallic particles. Among these, organic particles and inorganic particles are preferred.

[0097] Examples of organic particles include those made of polymethyl methacrylate, polyacrylic-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, benzoguanamine-melamine-formaldehyde condensate, silicone, fluororesin, and polyester resin. Organic particles are preferred because they have good dispersibility, making it easy to control Sa and Ssk.

[0098] The average particle size of the organic particles is preferably 0.5 μm or more at the lower limit, more preferably 1.0 μm or more, and even more preferably 2.0 μm or more. The upper limit is preferably 5.0 μm or less, more preferably 4.0 μm or less, and even more preferably 3.0 μm or less. By setting the average particle size of organic particles to 0.5 μm or more, it is easier to suppress excessively low Sa. Also, when the mass-based content of organic particles is the same, the number of organic particles decreases as the average particle size increases. For this reason, if the average particle size of organic particles is too large, independent, steep convex parts tend to form, which tends to increase Ssk. Therefore, by setting the average particle size of organic particles to 5.0 μm or less, it is easier to suppress excessively high Ssk. Embodiments of the average particle diameter range for organic particles include 0.5 μm to 5.0 μm, 0.5 μm to 4.0 μm, 0.5 μm to 3.0 μm, 1.0 μm to 5.0 μm, 1.0 μm to 4.0 μm, 1.0 μm to 3.0 μm, 2.0 μm to 5.0 μm, 2.0 μm to 4.0 μm, and 2.0 μm to 3.0 μm.

[0099] The average particle size of organic particles can be calculated, for example, by following the steps (A1) to (A3) below. (A1) Obtain a transmission image of the optical laminate using an optical microscope. A magnification of 500x to 2000x is preferred. (A2) After extracting 10 arbitrary organic particles from the observation image, the particle diameter of each organic particle is calculated. The particle diameter is measured as the distance between two lines in a combination of two lines that maximizes the distance between the two lines when the cross-section of the particle is enclosed by two arbitrary parallel lines. (A3) After performing the same procedure five times on observation images of the same sample on different screens, the average particle size of the organic particles is taken from the number average of the particle sizes of a total of 50 particles.

[0100] The organic particles preferably have a coefficient of variation of particle size of 13% or less, more preferably 12% or less, and even more preferably 11% or less. By setting the coefficient of variation of the particle size of organic particles to 13% or less, it becomes easier to control Sa and Ssk. The coefficient of variation of the particle size of organic particles can be obtained, for example, from the standard deviation calculated from the 50 particles used to calculate the average particle size in (A1) to (A3) above, and the average particle size, using the following formula. Coefficient of variation (%) = (Standard deviation / Average particle size) × 100

[0101] Examples of inorganic particles include those made of silica, alumina, zirconia, and titania. Among these, silica is preferred for good transparency. Fumed silica is particularly preferred among silicas.

[0102] Fumed silica is amorphous silica with a particle size of 200 nm or less, produced by a dry process, and can be obtained by reacting silicon-containing volatile compounds in the gas phase. Specifically, examples include silica produced by hydrolyzing silicon compounds such as silicon tetrachloride in an oxygen and hydrogen flame. Fumed silica is suitable because its surface is easily subjected to hydrophobic treatment.

[0103] When inorganic particles are used individually, it is preferable that multiple inorganic particles aggregate together to form aggregates, and that these aggregates impart irregularities to the uneven layer. Furthermore, by subjecting inorganic particles to hydrophobic treatment, aggregates can be formed in which the inorganic particles adhere to organic particles. For this reason, when comparing a system with organic particles alone with a system using both organic and inorganic particles, the system using both organic and inorganic particles tends to have a larger Sa. On the other hand, because inorganic particles form gentle irregularities, when comparing a system with organic particles alone with a system using both organic and inorganic particles, the system using both organic and inorganic particles tends to have a smaller Ssk. Furthermore, when inorganic particles are used alone, the height of the protrusions tends to be lower and the overall surface tends to have a smoother, more evenly shaped uneven surface compared to when organic particles are used alone.

[0104] Inorganic particles are preferably those with a hydrophobic surface treatment. By hydrophobicizing the surface of inorganic particles, excessive aggregation of inorganic particles can be suppressed. Furthermore, by using a combination of hydrophobic inorganic particles and organic particles, it is possible to increase Sa and Ssk as described above. Inorganic particles with hydrophobic surfaces include those having a reaction product between the functional groups on the surface of the inorganic particles and a surface treatment agent. Examples of functional groups on the surface of inorganic particles include the silanol groups of silica particles.

[0105] Examples of surface treatment agents include one or more selected from trimethylsilyl chloride, dimethyldichlorosilane, trimethylsilyltrifluoromethanesulfonate, chloromethyltrimethylsilane, hexamethyldisilazane, triethylsilane, triethylsilyl chloride, triisopropylsilyl chloride, t-butyldimethylsilane, t-butyldimethylsilyl chloride, octylsilane, hexadecylsilane, allyltrimethylsilane, trimethylvinylsilane, aminosilane, methacrylatesilane, and polydimethylsiloxane.

[0106] Surface treatment agents preferably have alkyl groups with a high number of carbon atoms in their molecules to enhance the degree of hydrophobicity. Specifically, surface treatment agents preferably have alkyl groups with 5 or more carbon atoms in their molecules, and more preferably have alkyl groups with 6 or more carbon atoms in their molecules. The alkyl groups may be linear or branched, but linear is preferred. Furthermore, if the number of carbon atoms in the alkyl group within the molecule is too high, the bulkiness of the surface treatment agent molecule will reduce the proportion of the functional groups on the surface of the inorganic particles that can react with the surface treatment agent. For this reason, the number of carbon atoms in the alkyl group of the surface treatment agent is preferably 20 or less, more preferably 16 or less, and even more preferably 12 or less.

[0107] When using inorganic particles alone, it is preferable to use inorganic particles that have been hydrophobized with different surface treatment agents in combination. This is because if only inorganic particles hydrophobized with the same surface treatment agent are used, excessive aggregation may occur due to the shared properties of the particles. When using inorganic particles hydrophobized with different surface treatment agents in combination, the number of carbon atoms in the alkyl group of the surface treatment agent for one of the inorganic particles is preferably 4 or more at the lower limit, more preferably 6 or more, and preferably 20 or less at the upper limit, more preferably 16 or less, and even more preferably 12 or less. Embodiments of the range of carbon atoms in the alkyl group of the surface treatment agent for one of the inorganic particles include 4 to 20, 4 to 16, 4 to 12, 6 to 20, 6 to 16, and 6 to 12. The number of carbon atoms in the alkyl group of the surface treatment agent for the other inorganic particle is preferably 3 or less, more preferably 2 or less, and even more preferably 1.

[0108] The average particle diameter of the inorganic particles is preferably 3 nm or more at the lower limit, more preferably 5 nm or more, even more preferably 8 nm or more, and preferably 100 nm or less at the upper limit, more preferably 50 nm or less, and even more preferably 30 nm or less. Examples of the range of average particle diameter for inorganic particles include 3 nm to 100 nm, 3 nm to 50 nm, 3 nm to 30 nm, 5 nm to 100 nm, 5 nm to 50 nm, 5 nm to 30 nm, 8 nm to 100 nm, 8 nm to 50 nm, and 8 nm to 30 nm. By setting the average particle diameter of inorganic particles within the above range, it becomes easier to control the uneven shape caused by aggregates of inorganic particles. Unless otherwise specified, the average particle diameter of inorganic particles in this specification refers to the average primary particle diameter. The average particle diameter of inorganic particles can be measured, for example, by laser scattering.

[0109] Metallic particles include particles made of metals such as gold and silver, and metal-coated particles in which the surface of organic particles is coated with metal. Metallic particles have a high specific gravity and do not easily float to the surface of the uneven layer, making it difficult to increase Sa. In addition, because metallic particles have low affinity for the binder resin, the protruding parts of metallic particles that protrude from the surface of the uneven layer are not coated with resin, forming steep protrusions. For this reason, metallic particles tend to have difficulty increasing Sa and have extremely high Ssk. For the reasons stated above, it is preferable that the uneven layer does not substantially contain metal-based particles.

[0110] The particle shape can be spherical, elliptical, or irregular, but spherical is preferred. Spherical particles make it easier to suppress the steepness of the uneven surface of the uneven layer, thus making it easier to prevent the Ssk from becoming excessively large.

[0111] The particle content is preferably at a lower limit of 0.3 parts by mass or more, more preferably at 0.4 parts by mass or more, and even more preferably at 0.5 parts by mass or more, with an upper limit of 12.0 parts by mass or less, more preferably at 11.0 parts by mass or less, and even more preferably at 10.0 parts by mass or less, per 100 parts by mass of binder resin. By setting the particle content to 0.3 parts by mass or more, it is easier to suppress the Sa of the uneven layer from becoming too small and the Ssk from becoming too large. Furthermore, by setting the particle content to 12.0 parts by mass or less, it is easier to suppress the Sa of the uneven layer from becoming too large. In addition, if the particles are organic particles, by setting the particle content to 12.0 parts by mass or less, it is easier to suppress the Ssk from becoming too small. Examples of the range of particle content per 100 parts by mass of binder resin include 0.3 parts by mass or more and 12.0 parts by mass or less, 0.3 parts by mass or more and 11.0 parts by mass or less, 0.3 parts by mass or more and 10.0 parts by mass or less, 0.4 parts by mass or more and 12.0 parts by mass or less, 0.4 parts by mass or more and 11.0 parts by mass or less, 0.4 parts by mass or more and 10.0 parts by mass or less, 0.5 parts by mass or more and 12.0 parts by mass or less, 0.5 parts by mass or more and 11.0 parts by mass or less, and 0.5 parts by mass or more and 10.0 parts by mass or less.

[0112] The average thickness of the uneven layer is preferably 0.5 μm or more at the lower limit, more preferably 0.7 μm or more, even more preferably 1.0 μm or more, and preferably 7.0 μm or less at the upper limit, more preferably 5.0 μm or less, and even more preferably 3.0 μm or less. By setting the average thickness of the textured layer to 0.5 μm or more, it becomes easier to suppress the Sa and Ssk of the textured layer from becoming too large. Conversely, by setting the average thickness of the textured layer to 7.0 μm or less, it becomes easier to suppress the Sa and Ssk of the textured layer from becoming too small. Embodiments of the average film thickness range of the uneven layer include 0.5 μm to 7.0 μm, 0.5 μm to 5.0 μm, 0.5 μm to 3.0 μm, 0.7 μm to 7.0 μm, 0.7 μm to 5.0 μm, 0.7 μm to 3.0 μm, 1.0 μm to 7.0 μm, 1.0 μm to 5.0 μm, and 1.0 μm to 3.0 μm.

[0113] The average film thickness of each layer constituting the optical laminate, such as the textured layer and the anti-fouling layer, can be calculated, for example, by selecting 20 arbitrary points from a cross-sectional image of the optical laminate taken with a scanning transmission electron microscope (STEM) and taking the average value. However, the 20 points should be selected so as not to be biased towards any particular location. The acceleration voltage and magnification of the STEM should be set according to the layer being measured. For example, in the case of an uneven layer, it is preferable that the acceleration voltage of the STEM be between 10kV and 30kV, and the magnification of the STEM be between 1000x and 7000x.

[0114] The uneven layer may contain other additives to the extent that they do not impair the effects of the present disclosure. Examples of additives include leveling agents, UV absorbers, antioxidants, and light stabilizers.

[0115] The refractive index of the uneven layer is preferably 1.48 or higher at the lower limit, more preferably 1.50 or higher, even more preferably 1.52 or higher, and preferably 1.58 or lower at the upper limit, more preferably 1.54 or lower, and even more preferably 1.53 or lower. By setting the refractive index of the uneven layer within the above range and the refractive index of the anti-fouling layer within the range described later, it is possible to easily lower the luminous reflectance Y value. Embodiments of the refractive index range of the uneven layer include 1.48 to 1.58, 1.48 to 1.54, 1.48 to 1.53, 1.50 to 1.58, 1.50 to 1.54, 1.50 to 1.53, 1.52 to 1.58, 1.52 to 1.54, and 1.52 to 1.53.

[0116] "solvent" Coating solutions for uneven surfaces typically use solvents to adjust viscosity or to dissolve or disperse the various components. Examples of solvents include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as dioxane and tetrahydrofuran; aliphatic hydrocarbons such as hexane; alicyclic hydrocarbons such as cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated carbons such as dichloromethane and dichloroethane; esters such as methyl acetate, ethyl acetate, and butyl acetate; alcohols such as isopropanol, butanol, and cyclohexanol; cellosolves such as methyl cellosolve and ethyl cellosolve; glycol ethers such as propylene glycol monomethyl ether acetate; cellosolve acetates; sulfoxides such as dimethyl sulfoxide; amides such as dimethylformamide and dimethylacetamide; and mixtures thereof.

[0117] If the drying time for the solvent in the coating solution for the textured layer is too long, the particles may aggregate excessively, resulting in an excessively large Ssk value. Conversely, if the drying time for the solvent in the coating solution for the textured layer is too short, the particles may not aggregate sufficiently, resulting in an excessively small Sa value. For this reason, it is preferable to use a mixture of a solvent with a fast evaporation rate and a solvent with a slow evaporation rate in the coating solution for the textured layer. In this specification, a solvent with a fast evaporation rate means a solvent whose evaporation rate is 100 or more, with the evaporation rate of butyl acetate set to 100. In this specification, a solvent with a slow evaporation rate means a solvent whose evaporation rate is less than 100, with the evaporation rate of butyl acetate set to 100.

[0118] In solvents for coating liquids for uneven surfaces, solvents with a fast evaporation rate preferably have a lower limit of 120 or more, more preferably 130 or more, and even more preferably 140 or more, and an upper limit of 400 or less, more preferably 300 or less, and even more preferably 220 or less. Examples of solvents with a fast evaporation rate include methyl isobutyl ketone with an evaporation rate of 160, methyl ethyl ketone with an evaporation rate of 370, toluene with an evaporation rate of 200, and 2-propanol with an evaporation rate of 150. Examples of the range of evaporation rates for solvents with a fast evaporation rate include 120 to 400, 120 to 300, 120 to 220, 130 to 400, 130 to 300, 130 to 220, 140 to 400, 140 to 300, and 140 to 220.

[0119] In solvents for coating liquids for uneven surfaces, solvents with a slow evaporation rate preferably have a lower limit of 15 or more, more preferably 20 or more, and even more preferably 25 or more. Similarly, solvents with a lower limit of 90 or less, more preferably 50 or less, and even more preferably 35 or less. Examples of solvents with a slow evaporation rate include cyclohexanone with an evaporation rate of 32 and propylene glycol monomethyl ether acetate with an evaporation rate of 44. Examples of the range of evaporation rates for solvents with slow evaporation rates include 15 to 90, 15 to 50, 15 to 35, 20 to 90, 20 to 50, 20 to 35, 25 to 90, 25 to 50, and 25 to 35.

[0120] In the solvent for the coating liquid for uneven layers, the mass ratio of the solvent with a fast evaporation rate to the solvent with a slow evaporation rate is preferably 50:50 to 90:10, more preferably 50:50 to 80:20 or 60:40 to 90:10, and even more preferably 60:40 to 80:20. Furthermore, the solvent content in the coating liquid for the uneven layer preferably has a lower limit of 30% by mass or more in solid content concentration, and more preferably 35% by mass or more. Furthermore, the solvent content in the coating liquid for the uneven layer preferably has an upper limit of 70% by mass or less in solid content concentration, and more preferably 45% by mass or less. Examples of the range of solvent content in the coating liquid for uneven layers include 30% by mass or more and 70% by mass or less, 30% by mass or more and 45% by mass or less, 35% by mass or more and 70% by mass or less, and 35% by mass or more and 45% by mass or less.

[0121] <Stain-resistant layer> The antifouling layer is located on the side of the uneven layer opposite to the easy-adhesion layer. It is preferable that the antifouling layer be formed in contact with the uneven layer. In other words, it is preferable that there are no other layers between the uneven layer and the antifouling layer. Furthermore, it is preferable to arrange the anti-fouling layer so that it forms the surface of the optical laminate.

[0122] Normally, significant stress is generated when other components come into contact with the surface of a laminate. Therefore, when other components come into contact with the surface of a laminate having an easy-adhesion layer and a functional layer such as a textured layer on a polyester film with a high degree of surface orientation ΔP, delamination occurs between the polyester film and the easy-adhesion layer due to the stress. This stress is largely influenced by lateral stress. However, when another component comes into contact with the surface of the antifouling layer of the optical laminate according to this disclosure, the other component slides due to the antifouling function of the antifouling layer, making it difficult for stress to be generated in the lateral direction. Furthermore, since irregularities are formed on the surface of the antifouling layer of the optical laminate according to this disclosure due to an uneven layer satisfying Equation 2-1, the irregularities make it difficult for other components to adhere to the surface of the optical laminate, thus reducing the generation of stress. As a result, the optical laminate according to this disclosure has good interlayer adhesion as a whole, and can suppress peeling of functional layers such as the easily adhesive layer and the uneven layer formed on a polyester film with a high degree of surface orientation ΔP.

[0123] Furthermore, since the optical laminate of this disclosure has an antifouling layer formed on an uneven layer satisfying Equation 2-1, it is possible to suppress thickness variations of the antifouling layer and, consequently, suppress the occurrence of localized defects in the optical laminate.

[0124] The antifouling layer can be formed, for example, from a coating solution for forming an antifouling layer that includes a binder resin composition and an antifouling agent. That is, an embodiment of the antifouling layer includes one that includes a binder resin and an antifouling agent.

[0125] The binder resin of the antifouling layer preferably contains a cured product of a curable resin composition. Examples of cured products of curable resin compositions include cured products of thermosetting resin compositions and cured products of ionizing radiation-curable resin compositions. Among the cured products of curable resin compositions, cured products of ionizing radiation-curable resin compositions are preferred in order to obtain better mechanical strength. Examples of curable resin compositions for the antifouling layer include the curable resin compositions exemplified for the uneven layer.

[0126] The resin composition forming the antifouling layer preferably includes a resin composition containing fluorine atoms as a constituent unit and a resin composition containing siloxane bonds as a constituent unit in order to improve antifouling properties. It is more preferable that these resin compositions are curable. When using a resin composition containing fluorine atoms as a constituent unit, or a resin composition containing siloxane bonds as a constituent unit, it is preferable to use it in combination with other resin compositions. As resin compositions other than those containing fluorine atoms as a constituent unit and resin compositions containing siloxane bonds as a constituent unit, curable resin compositions are preferred.

[0127] The ratio of cured product of the curable resin composition to the total binder resin of the antifouling layer is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0128] Examples of antifouling agents include fluorine-based leveling agents and silicone-based leveling agents. The antifouling agent is preferably one that has reactive groups that can react with the binder resin composition in order to suppress bleed-out from the antifouling layer. In other words, it is preferable that the antifouling agent is immobilized on the binder resin composition within the antifouling layer. Furthermore, to suppress bleed-out from the antifouling layer, self-crosslinking antifouling agents are also preferred.

[0129] The amount of antifouling agent in the antifouling layer is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, and more preferably 25 parts by mass or less, per 100 parts by mass of the binder resin of the antifouling layer. Examples of the range of antifouling agent content in the antifouling layer include 5 to 30 parts by mass, 5 to 25 parts by mass, 10 to 30 parts by mass, and 10 to 25 parts by mass per 100 parts by mass of the binder resin of the antifouling layer.

[0130] The thickness of the antifouling layer is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 110 nm or less. By making the thickness of the antifouling layer 200 nm or less, the uneven shape of the uneven layer is more easily reflected on the surface of the antifouling layer, making it easier to improve the adhesion of the optical laminate. If the antifouling layer is too thin, the in-plane uniformity of the antifouling properties may be impaired, potentially reducing the adhesion of the optical laminate. Furthermore, if the antifouling layer is too thin, localized defects such as bright spots are more likely to occur in the optical laminate. Therefore, the thickness of the antifouling layer is preferably 50 nm or more, more preferably 70 nm or more, and even more preferably 90 nm or more. Embodiments of the thickness range of the antifouling layer include 200 nm or less, 50 nm to 200 nm, 50 nm to 150 nm, 50 nm to 110 nm, 70 nm to 200 nm, 70 nm to 150 nm, 70 nm to 110 nm, 90 nm to 200 nm, 90 nm to 150 nm, and 90 nm to 110 nm.

[0131] As described later, when the refractive index of the antifouling layer is reduced, in order to lower the luminous reflectance Y value, the thickness of the antifouling layer is preferably 80 nm or more at the lower limit, more preferably 85 nm or more, even more preferably 90 nm, and preferably 120 nm or less at the upper limit, more preferably 110 nm or less, and even more preferably 105 nm or less. In this case, it is preferable that the thickness of the antifouling layer is greater than the average particle diameter of the particles contained in the antifouling layer, such as hollow particles and non-hollow particles. Embodiments of thickness ranges when the antifouling layer has a low refractive index include 80 nm to 120 nm, 80 nm to 110 nm, 80 nm to 105 nm, 85 nm to 120 nm, 85 nm to 110 nm, 85 nm to 105 nm, 90 nm to 120 nm, 90 nm to 110 nm, and 90 nm to 105 nm.

[0132] The contact angle of the antifouling layer surface with respect to pure water is preferably 80 degrees or more, more preferably 85 degrees or more, and even more preferably 90 degrees or more. By setting the contact angle to 80 degrees or more, the slipperiness when other components come into contact with the surface of the optical laminate is improved, making it easier to improve the adhesion of the optical laminate. If the contact angle of pure water with the antifouling layer is too large, the ratio of the antifouling agent to the total solid content of the antifouling layer increases, which may lead to a decrease in physical properties such as the hardness of the antifouling layer. For this reason, the contact angle is preferably 130 degrees or less, and more preferably 120 degrees or less. Embodiments of the range of contact angles of the antifouling layer with respect to pure water include 80 degrees to 130 degrees, 80 degrees to 120 degrees, 85 degrees to 130 degrees, 85 degrees to 120 degrees, 90 degrees to 130 degrees, and 90 degrees to 120 degrees. In this specification, the contact angle refers to the static contact angle measured by the θ / 2 method. For pure water, general-purpose pure water can be used. Pure water generally has a resistivity of 0.1 MΩ·cm to 15 MΩ·cm.

[0133] The antifouling layer may have a low refractive index. Specifically, the refractive index of the antifouling layer is preferably 1.10 or higher at the lower limit, more preferably 1.20 or higher, more preferably 1.26 or higher, more preferably 1.28 or higher, and more preferably 1.30 or higher. The upper limit is preferably 1.48 or lower, more preferably 1.45 or lower, more preferably 1.40 or lower, more preferably 1.38 or lower, and more preferably 1.32 or lower. By setting the refractive index of the antifouling layer within the above range, it is possible to easily lower the luminous reflectance Y value. Embodiments of the refractive index range for the anti-fouling layer include: 1.10 to 1.48, 1.10 to 1.45, 1.10 to 1.40, 1.10 to 1.38, 1.10 to 1.32, 1.20 to 1.48, 1.20 to 1.45, 1.20 to 1.40, 1.20 to 1.38, 1.20 to 1.32, 1.26 to 1.48, and 1.26 to 1.45. Examples include 1.26 to 1.40, 1.26 to 1.38, 1.26 to 1.32, 1.28 to 1.48, 1.28 to 1.45, 1.28 to 1.40, 1.28 to 1.38, 1.28 to 1.32, 1.30 to 1.48, 1.30 to 1.45, 1.30 to 1.40, 1.30 to 1.38, and 1.30 to 1.32.

[0134] When the antifouling layer has a low refractive index, it is preferable that the antifouling layer contains particles. The antifouling layer particles preferably include hollow particles and non-hollow particles. That is, the antifouling layer with a low refractive index preferably includes a binder resin, hollow particles, and non-hollow particles.

[0135] Hollow particles and non-hollow particles The material of the hollow and non-hollow particles may be any inorganic compound such as silica and magnesium fluoride, or an organic compound, but silica is preferred for its low refractive index and strength. Below, hollow and non-hollow particles will be described, focusing mainly on hollow silica particles and non-hollow silica particles.

[0136] Hollow silica particles are particles that have an outer shell layer made of silica, with a hollow interior surrounded by the outer shell layer, and that contain air within the hollow interior. Hollow silica particles have a refractive index that decreases in proportion to the gas occupancy rate compared to the original refractive index of silica due to the presence of air. Non-hollow silica particles are particles that do not have a hollow interior like hollow silica particles. Non-hollow silica particles are, for example, solid silica particles. The shape of the hollow silica particles and non-hollow silica particles is not particularly limited and may be spherical, ellipsoidal, or approximately spherical, such as a polyhedron that can approximate a sphere. Among these, a spherical, ellipsoidal, or approximately spherical shape is preferred when considering scratch resistance.

[0137] Hollow silica particles, because they contain air, play a role in lowering the refractive index of the entire antifouling layer. By using hollow silica particles with a larger particle size and a higher air content, the refractive index of the antifouling layer can be further reduced. On the other hand, hollow silica particles tend to have inferior mechanical strength. In particular, when using hollow silica particles with a larger particle size and a higher air content, the scratch resistance of the antifouling layer tends to decrease. Non-hollow silica particles, when dispersed in the binder resin, play a role in improving the scratch resistance of the anti-fouling layer.

[0138] It is preferable to set the average particle diameter of hollow silica particles and non-hollow silica particles such that the hollow silica particles are close together and that non-hollow particles can fit between the hollow silica particles. Specifically, the ratio of the average particle diameter of non-hollow silica particles to the average particle diameter of hollow silica particles, known as "average particle diameter of non-hollow silica particles / average particle diameter of hollow silica particles," is preferably 0.29 or less, and more preferably 0.27 or less. By setting the ratio of average particle diameters within the above range, hollow silica particles and non-hollow silica particles can be more easily dispersed uniformly in the film thickness direction of the antifouling layer, thereby improving scratch resistance. The ratio of average particle diameters is preferably 0.05 or more, and more preferably 0.15 or more. Embodiments of the average particle diameter ratio range include 0.05 to 0.29, 0.05 to 0.27, 0.15 to 0.29, and 0.15 to 0.27.

[0139] Considering optical properties and mechanical strength, the average particle diameter of hollow silica particles is preferably 50 nm or more at the lower limit, more preferably 60 nm or more, and preferably 100 nm or less at the upper limit, more preferably 80 nm or less. Embodiments of the average particle diameter range of hollow silica particles include 50 nm to 100 nm, 50 nm to 80 nm, 60 nm to 100 nm, and 60 nm to 80 nm. When considering dispersibility while preventing aggregation of non-hollow silica particles, the lower limit of the average particle diameter is preferably 5 nm or more, more preferably 10 nm or more, and the upper limit is preferably 20 nm or less, more preferably 15 nm or less. Embodiments of the average particle diameter range of non-hollow silica particles include 5 nm to 20 nm, 5 nm to 15 nm, 10 nm to 20 nm, and 10 nm to 15 nm.

[0140] It is preferable that the hollow silica particles and non-hollow silica particles have their surfaces coated with a silane coupling agent. The silane coupling agent is preferably one having (meth)acryloyl groups or epoxy groups. By surface-treating silica particles with a silane coupling agent, the affinity between the silica particles and the binder resin is improved, making aggregation of the silica particles less likely. This makes it easier to achieve uniform dispersion of the silica particles. Furthermore, by improving the affinity between the silica particles and the binder resin with the silane coupling agent, the resistance to the flow of the wet antifouling layer formed on the convex parts of the uneven layer to the flat parts of the uneven layer is increased. This makes it easier to suppress excessive reduction in the film thickness of the antifouling layer on the convex parts of the uneven layer. This makes it easier to suppress localized defects in the optical laminate.

[0141] The higher the content of hollow silica particles, the higher the packing density of hollow silica particles in the binder resin, and the lower the refractive index of the antifouling layer. Furthermore, as the content of hollow silica particles increases, the viscosity of the coating liquid for the antifouling layer increases, which increases the resistance when the wet antifouling layer formed on the convex parts of the uneven layer flows down to the flat parts of the uneven layer. This makes it easier to suppress excessive reduction in the film thickness of the antifouling layer on the convex parts of the uneven layer. Therefore, it is easier to suppress localized defects in the optical laminate. For this reason, the content of hollow silica particles is preferably 100 parts by mass or more, and more preferably 130 parts by mass or more, per 100 parts by mass of binder resin. On the other hand, if the content of hollow silica particles is too high, the mechanical strength, such as scratch resistance, of the antifouling layer tends to decrease. Also, if the content of hollow silica particles is too high, the content of the antifouling agent relatively decreases, which tends to reduce the antifouling properties. For this reason, the content of hollow silica particles is preferably 300 parts by mass or less, and more preferably 200 parts by mass or less, per 100 parts by mass of binder resin. Examples of the range of content of hollow silica particles per 100 parts by mass of binder resin include 100 parts by mass or more and 400 parts by mass or less, 100 parts by mass or more and 300 parts by mass or less, 130 parts by mass or more and 400 parts by mass or less, and 130 parts by mass or more and 300 parts by mass or less.

[0142] If the content of non-hollow silica particles is low, the presence of non-hollow silica particles on the surface of the antifouling layer may not affect the hardness increase. Furthermore, as the content of non-hollow silica particles increases, the viscosity of the coating liquid for the antifouling layer increases, which increases the resistance when the wet antifouling layer formed on the convex parts of the uneven layer flows down to the flat parts of the uneven layer. This makes it easier to suppress excessive reduction in the film thickness of the antifouling layer on the convex parts of the uneven layer. Therefore, it is easier to suppress local defects in the optical laminate. In addition, as the content of non-hollow silica particles increases, it is easier to reduce the effect of shrinkage unevenness due to polymerization of the binder resin. For this reason, the content of non-hollow silica particles is preferably 10 parts by mass or more, and more preferably 20 parts by mass or more, per 100 parts by mass of binder resin. On the other hand, if the content of non-hollow silica particles is too high, the content of the antifouling agent relatively decreases, which tends to reduce the antifouling properties. For this reason, the content of non-hollow silica particles is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of binder resin. Examples of the range of content of non-hollow silica particles per 100 parts by mass of binder resin include 10 parts by mass or more and 150 parts by mass or less, 10 parts by mass or more and 100 parts by mass or less, 10 parts by mass or more and 50 parts by mass or less, 20 parts by mass or more and 150 parts by mass or less, 20 parts by mass or more and 100 parts by mass or less, and 20 parts by mass or more and 50 parts by mass or less.

[0143] The antifouling layer may contain other additives to the extent that they do not impair the effects of the present disclosure. Examples of additives include ultraviolet absorbers, antioxidants, and light stabilizers.

[0144] "solvent" In coating solutions for antifouling layers, solvents are typically used to adjust viscosity or to dissolve or disperse each component. The solvent for the antifouling coating liquid is the same as that exemplified for the solvent for the textured coating liquid.

[0145] If the drying time of the solvent in the antifouling coating solution is too long, the wet antifouling layer formed on the raised parts of the uneven layer may excessively flow down to the flat parts of the uneven layer, potentially reducing the film thickness of the antifouling layer on the raised parts excessively. Conversely, if the drying time of the solvent in the antifouling coating solution is too short, the leveling properties of the antifouling layer may be insufficient. For this reason, it is preferable to use a mixture of a solvent with a fast evaporation rate and a solvent with a slow evaporation rate in the antifouling coating solution.

[0146] In solvents for antifouling coatings, solvents with a fast evaporation rate preferably have a lower limit of 125 or more evaporation rate, more preferably 130 or more, and even more preferably 150 or more, while preferably have an upper limit of 450 or less evaporation rate, more preferably 430 or less, and even more preferably 400 or less. Examples of the range of evaporation rates for solvents with a fast evaporation rate include 125 to 450, 125 to 430, 125 to 400, 130 to 450, 130 to 430, 130 to 400, 150 to 450, 150 to 430, and 150 to 400.

[0147] In solvents for antifouling coatings, solvents with a slow evaporation rate preferably have a lower limit of 20 or more, more preferably 30 or more, and even more preferably 40 or more, while preferably have an upper limit of 90 or less, more preferably 60 or less, and even more preferably 50 or less. Embodiments of the evaporation rate range for solvents with a slow evaporation rate include 20 to 90, 20 to 60, 20 to 50, 30 to 90, 30 to 60, 30 to 50, 40 to 90, 40 to 60, and 40 to 50.

[0148] In the solvent for the antifouling coating liquid, the mass ratio of the fast-evaporating solvent to the slow-evaporating solvent is preferably 50:50 to 90:10, more preferably 50:50 to 80:20 or 60:40 to 90:10, and even more preferably 60:40 to 80:20. Furthermore, the solvent content in the antifouling coating liquid preferably has a lower limit of 1% by mass or more in solid content concentration, and more preferably 2% by mass or more. Furthermore, the solvent content in the antifouling coating liquid preferably has an upper limit of 10% by mass or less in solid content concentration, and more preferably 5% by mass or less. Examples of the range of solvent content in the antifouling coating liquid include 1% by mass or more and 10% by mass or less, 1% by mass or more and 5% by mass or less, 2% by mass or more and 10% by mass or less, and 2% by mass or more and 5% by mass or less.

[0149] <Physical properties> The optical laminate preferably has a luminous reflectance Y value of 3.0% or less, and more preferably 2.0% or less, measured at a light incidence angle of 5 degrees from the side having the anti-fouling layer. While there is no particular lower limit to the luminous reflectance Y value, it is usually around 0.5%. In this specification, the luminous reflectance Y value refers to the luminous reflectance Y value of the CIE 1931 standard color system. The luminous reflectance Y value can be calculated using a spectrophotometer. When measuring luminous reflectance, it is preferable to attach a black plate to the back surface of the substrate. An example of a spectrophotometer is the "UV-3600plus" manufactured by Shimadzu Corporation. The luminous reflectance (Y value), total light transmittance, and haze are calculated as the average value measured at 10 locations.

[0150] The optical laminate preferably has a total light transmittance of 50% or more, more preferably 80% or more, and even more preferably 90% or more, according to JIS K7361-1:1997. Total light transmittance and the haze described below shall be measured with the light incident surface facing the polyester film. Total light transmittance and the haze described below can be measured, for example, with a haze meter (product number: HM-150) manufactured by Murakami Color Technology Laboratory.

[0151] The optical laminate preferably has a haze of 0.3% or more, more preferably 0.4% or more, even more preferably 0.5% or more, with an upper limit of 10% or less, more preferably 7% or less, and even more preferably 5% or less, in accordance with JIS K7136:2000. Embodiments of the haze range of the optical laminate include 0.3% to 10%, 0.3% to 7%, 0.3% to 5%, 0.4% to 10%, 0.4% to 7%, 0.4% to 5%, 0.5% to 10%, 0.5% to 7%, and 0.5% to 5%.

[0152] <Size, shape, etc.> The optical laminate may be in the form of a single sheet cut to a predetermined size, or in the form of a roll formed by winding a long sheet into a roll. The size of the sheet is not particularly limited, but the maximum diameter is approximately 2 inches to 500 inches. "Maximum diameter" refers to the maximum length when connecting any two points on the optical laminate. For example, if the optical laminate is rectangular, the diagonal of the rectangle is the maximum diameter. If the optical laminate is circular, the diameter of the circle is the maximum diameter. The width and length of the roll are not particularly limited, but generally, the width is between 500 mm and 8000 mm, and the length is between 100 m and 10000 m. The optical laminate in roll form can be cut into individual sheets to match the size of an image display device or the like. When cutting, it is preferable to remove the roll ends, which have unstable physical properties. The shape of the sheet is not particularly limited; for example, it may be a polygon such as a triangle, square, or pentagon, or it may be circular, or it may be a random, irregular shape. More specifically, if the optical laminate is rectangular, the aspect ratio is not particularly limited as long as it does not cause problems as a display screen. Examples include width:height = 1:1, 4:3, 16:10, 16:9, 2:1, 5:4, 11:8, etc.

[0153] [Polarizing plate] The polarizing plate of the present disclosure is a polarizing plate having a polarizer, a first transparent protective plate disposed on one side of the polarizer, and a second transparent protective plate disposed on the other side of the polarizer, wherein at least one of the first transparent protective plate and the second transparent protective plate is the optical laminate of the present disclosure described above, and the optical laminate is arranged such that the surface facing the antifouling layer faces away from the polarizer.

[0154] <Polarizer> Examples of polarizers include sheet-type polarizers such as polyvinyl alcohol film, polyvinyl formal film, polyvinyl acetal film, and ethylene-vinyl acetate copolymer saponified film dyed with iodine or the like and stretched; wire grid-type polarizers consisting of numerous parallel metal wires; coated polarizers coated with lyotropic liquid crystal or dichroic guest-host materials; and multilayer thin-film polarizers. These polarizers may also be reflective polarizers that have the function of reflecting polarization components that do not transmit through them.

[0155] <Transparent protection plate> A first transparent protective plate is placed on one side of the polarizer, and a second transparent protective plate is placed on the other side. At least one of the first and second transparent protective plates is the optical laminate of the present disclosure described above.

[0156] Examples of the first and second transparent protective plates other than the optical laminate include plastic films and glass. Examples of plastic films include polyester films, polycarbonate films, cycloolefin polymer films, and acrylic films, and stretched films of these are preferred to improve mechanical strength. Examples of glass include alkali glass, nitride glass, soda-lime glass, borosilicate glass, and lead glass. Furthermore, it is preferable that the glass used as a transparent protective plate to protect the polarizer is also used for other components of the image display device. For example, it is preferable to use the same glass substrate for the liquid crystal display element and the same transparent protective plate to protect the polarizer. Furthermore, it is preferable to bond the polarizer and the transparent protective plate together using an adhesive. A general-purpose adhesive can be used, and a PVA-based adhesive is preferred.

[0157] In the polarizing plate of this disclosure, both the first transparent protective plate and the second transparent protective plate may be the optical laminate of this disclosure described above, but it is preferable that one of the first transparent protective plate and the second transparent protective plate is the optical laminate of this disclosure described above. Furthermore, when the polarizing plate of this disclosure is used as a polarizing plate placed on the light-emitting surface side of a display element, it is preferable that the transparent protective plate on the light-emitting surface side of the polarizer is the optical laminate of this disclosure described above. On the other hand, when the polarizing plate of this disclosure is used as a polarizing plate placed on the opposite side of the light-emitting surface of a display element, it is preferable that the transparent protective plate on the opposite side of the light-emitting surface of the polarizer is the optical laminate of this disclosure described above.

[0158] [Surface plate for image display device] The surface plate for an image display device according to the present disclosure is a surface plate for an image display device in which an optical laminate is bonded to a resin plate or a glass plate, wherein the optical laminate is the optical laminate of the present disclosure described above, and the optical laminate is arranged such that the surface on the anti-fouling layer side faces away from the resin plate or the glass plate.

[0159] For image display devices, it is preferable to arrange the surface plate such that the side to which the optical laminate is bonded faces the surface side. In other words, it is preferable to arrange the surface plate for image display devices such that the side to which the optical laminate is bonded faces away from the display elements.

[0160] As the resin plate or glass plate, a resin plate or glass plate commonly used as a surface plate for image display devices can be used.

[0161] The thickness of the resin or glass plate is preferably 10 μm or more to ensure good strength. The upper limit of the thickness of the resin or glass plate is usually 5000 μm or less, but in recent years, as thinner image display devices are preferred, it is preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 100 μm or less. Embodiments of the thickness range of the resin plate or glass plate include 10 μm to 5000 μm, 10 μm to 1000 μm, 10 μm to 500 μm, and 10 μm to 100 μm.

[0162] [Image display device] The image display device of the present disclosure is configured such that the surface of the optical laminate of the present disclosure described above faces away from the display element, and the optical laminate is positioned on the surface.

[0163] Examples of display elements include liquid crystal display elements, organic EL display elements, inorganic EL display elements, and other EL display elements, as well as plasma display elements. Furthermore, LED display elements such as mini-LED display elements and micro-LED display elements are also included. These display elements may have a touch panel function inside the display element. Examples of liquid crystal display methods for liquid crystal display elements include IPS, VA, multi-domain, OCB, STN, and TSTN methods. When the display element is a liquid crystal display element, a backlight is required. The backlight is positioned on the side of the liquid crystal display element opposite to the side with the optical laminate. Examples of backlights include quantum dot backlights and white light-emitting diode backlights. The image display device may be a foldable image display device or a rollable image display device. Furthermore, the image display device may be an image display device with a touch panel. [Examples]

[0164] The present disclosure will be described in detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the forms described in the examples.

[0165] 1. Evaluation and Measurement The optical laminates obtained in Examples 1-20 and Comparative Examples 1-21 were subjected to the measurements and evaluations described in 1-1 to 1-6 below. The results are shown in Tables 1-4. Unless otherwise specified, the atmosphere during each measurement and evaluation was a temperature of 23±5°C and a relative humidity of 40% to 65%. Before starting each measurement and evaluation, the target sample was exposed to the aforementioned atmosphere for at least 30 minutes.

[0166] 1-1. Measurement of Sa and Ssk In the examples and comparative examples, the surface shape of the uneven layer was measured on a polyester film (PET film) after forming an easy-adhesion layer and an uneven layer, but before forming the anti-fouling layer. From the measured surface shape, Sa, Ssk, and "A" in Equation 2-1 were calculated. A laser microscope (Olympus product name "LEXT OLS4000") was used to measure and analyze the surface shape under the following conditions. Sa and Ssk measured by the laser microscope conform to ISO 25178:2012. The results are shown in Tables 1 to 4.

[0167] <Measurement conditions> Objective lens: MPLAPONLEXT50 (50x lens) Zoom: ×1 Image size (pixels): 1024 x 1024 Image size: 258μm × 259μm Cutoff value: Do not set <Analysis conditions> Analysis mode: Surface Calculation type: Roughness

[0168] 1-2. Adhesion A grid of 100 cuts was formed by inserting a cutter blade into the anti-fouling layer side of the optical laminates in the examples and comparative examples (11 cuts in the vertical and horizontal directions, with a cut interval of 1 mm). The cutter blade used was NT Corporation's product number "BA-52P". Next, adhesive tape (Nichiban Co., Ltd., product name "Sellotape®") was applied to the grid-patterned surface of the optical laminates, and then the adhesive tape was peeled off to perform a peel test in accordance with the cross-cut method specified in JIS K5600-5-6:1999. The adhesion of the optical laminates in the examples and comparative examples was evaluated according to the following evaluation criteria. <Evaluation Criteria> A: The number of detached squares is 0, and there are no squares that are partially missing. B: Although the number of detached squares is 0, there are areas where parts of the squares are missing, such as when a part of the square is missing along a cut. C: The number of detached squares is 1 or more.

[0169] 1-3. Bright spot The optical laminates of the examples and comparative examples were placed on a horizontal table with the antifouling layer facing upwards. Under bright room conditions, the presence or absence of bright spots was visually evaluated from various angles where the reflected light from the fluorescent lamp (the illumination source) could be observed. The evaluation was performed from a straight-line distance of approximately 50 cm above the sample. The bright room conditions were set so that the illuminance on the sample was between 500 lux and 1000 lux. An Hf32 type straight tube three-wavelength daylight white fluorescent lamp was used for illumination. The illumination position was 2 m vertically above the horizontal table. Twenty subjects, five from each age group (20s, 20s, 30s, 40s, 50s), evaluated the bright spots, assigning 3 points for those who did not notice them, 2 points for those who were unsure, and 1 point for those who noticed them. The average score of the 20 subjects was calculated, and the products were ranked according to the following criteria. <Evaluation Criteria> A: Average score is 2.5 or higher B: Average score is between 2.0 and 2.5 C: Average score is less than 2.0

[0170] 1-4.Contact angle Using a contact angle meter (manufactured by Kyowa Interface Science, part number: DM-300), 1.0 μL of pure water was dropped onto the surface of the antifouling layer side of the optical laminates in the examples and comparative examples, and the static contact angle 10 seconds after dropping was measured according to the θ / 2 method. Three measurements were taken, and the average value was taken as the contact angle for each example and comparative example.

[0171] 1-5. Luminous reflectance Y value (reflectance) A 5cm x 5cm sample was prepared by laminating a black plate (Kuraray Co., Ltd., product name: Comoglass DFA2CG 502K (black) series, 2mm thick) to the substrate side of the optical laminate of the examples and comparative examples via a 25μm thick transparent adhesive layer (Panac Co., Ltd., product name: Panaclean PD-S1). With the direction perpendicular to the surface of the anti-fouling layer of the optical laminate set to 0 degrees, light was incident on the sample from a direction of 5 degrees, and the luminous reflectance Y value, which is the reflectance of the sample, was measured based on the specular reflection of the incident light. The reflectance was determined using a spectrophotometer (JASCO, product name: V-7100) with a field of view of 2 degrees, a C light source, and a wavelength range of 380 nm to 780 nm. The 5-degree specular reflection was measured, and then converted to the perceived brightness using software (JASCO Spectrum Manager Ver2.0). Ten measurements were taken within the sample, and the average of these ten measurements was used as the reflectance for each example and comparative example. A 5 mm x 10 mm mask was used during measurement. Therefore, the size of the measurement spot for reflectance at an incident angle of 5 degrees was 50.2 mm. 2 That is the case.

[0172] 1-6. Total light transmittance (Tt) and haze (Hz) Using a haze meter (HM-150, manufactured by Murakami Color Technology Laboratory), the total light transmittance according to JIS K7361-1:1997 and the haze according to JIS K7136:2000 were measured for the optical laminates of the examples and comparative examples. The light incident surface was the polyester film side.

[0173] 2. Synthesis of Compound A (urethane acrylate oligomer) After introducing air into a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet, 10.0 parts by mass of 1,3-butanediol, 10.0 parts by mass of 1,4-butanediol, 0.1 parts by mass of p-methoxyphenol, 0.1 parts by mass of dibutyltin dilaurate, and 100.0 parts by mass of methyl ethyl ketone were charged, and the mixture was heated to 50°C while stirring under a nitrogen stream. Meanwhile, 50.3 parts by mass of isophorone diisocyanate was charged into a dropping container and uniformly added to the reaction vessel over 1 hour. During this time, the temperature of the reaction vessel was maintained at 50±3°C. After maintaining the temperature for 1 hour while stirring, an additional 0.1 parts by mass of p-methoxyphenol and 0.1 parts by mass of dibutyltin dilaurate were added, and the mixture was heated to 60°C while stirring under a nitrogen stream. Subsequently, 176.0 parts by mass of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate in a mass ratio of 80:20, which had been placed in a dropping vessel, were uniformly added dropwise to the reaction vessel over 1 hour while stirring. After the dropwise addition was complete, the dropping container was washed with 120.0 parts by mass of methyl ethyl ketone, and the washed solution was directly added to the reaction vessel. After further stirring and incubation for 2 hours, the temperature was raised to 75°C. Subsequently, stirring and incubation were continued at 75±3°C until the peak derived from isocyanate in the infrared absorption spectrum disappeared. The peak derived from isocyanate disappeared in approximately 4 to 6 hours. After confirming the disappearance of this peak, the temperature was lowered to 60°C, 7.0 parts by mass of methanol was added, and the mixture was incubated at 60±3°C for 30 minutes. Then, 120.8 parts by mass of methyl ethyl ketone was added to obtain a clear resin solution. Finally, the solvent was removed using an evaporator to obtain compound A, a urethane acrylate oligomer. The weight-average molecular weight of the obtained compound A was 2000.

[0174] 3. Preparation of the coating solution (1) Coating liquid 1 for uneven layer The following materials were diluted with a mixed solvent of methyl isobutyl ketone and methyl ethyl ketone in a mass ratio of 35:65 to achieve a solid content concentration of 40% by mass, to prepare coating solution 1 for uneven layers. <Materials for coating liquid 1 for uneven layers> Pentaerythritol triacrylate: 56 parts by mass (Nippon Kayakusha, product name "PET-30", solid content 100% by mass) • UV-curable acrylate-containing composition: 44 parts by mass (Daiichi Kogyosha Pharmaceutical Co., Ltd., product name "New Frontier R-1403MB", solid content 80% by mass) • Photopolymerization initiator: 3 parts by mass (IGM Resins BV, product name "Omnirad184") • Leveling agent: 3 parts by mass (DIC Corporation, product name "Megafac F-568", solid content 5% by mass)

[0175] (2) Coating liquid 2 for uneven layer The following materials were diluted with a mixed solvent of toluene, 2-propanol, and cyclohexanone in a mass ratio of 60:10:30 to achieve a solid content concentration of 40% by mass, to prepare coating solution 2 for uneven layers. <Materials for coating solution 2 for uneven layers> Pentaerythritol tetraacrylate: 45 parts by mass (Product name: PETA, Daicel Sci-Tec Corporation) • Urethane acrylate oligomer: 55 parts by mass (Mitsubishi Chemical Corporation, product name "UV-1700B", solid content 100% by mass) • Photopolymerization initiator: 3 parts by mass (IGM Resins BV, product name "EsaCure 1") ·Organic particles: 0.5 parts by mass (Acrylic beads, average particle size 2.2 μm, refractive index 1.559, coefficient of variation: 10.4%) Leveling agent: 0.5 parts by mass (Dainichi Seika Kogyo Co., Ltd., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0176] (3) Coating liquid 3 for uneven layer The following materials were diluted with a mixed solvent of toluene, 2-propanol, and cyclohexanone in a mass ratio of 60:10:30 to achieve a solid content concentration of 40% by mass, to prepare coating solution 3 for uneven layers. <Materials for coating liquid 3 for uneven layers> Pentaerythritol tetraacrylate: 45 parts by mass (Product name: PETA, Daicel Sci-Tec Corporation) • Urethane acrylate oligomer: 55 parts by mass (Mitsubishi Chemical Corporation, product name "UV-1700B", solid content 100% by mass) • Photopolymerization initiator: 3 parts by mass (IGM Resins BV, product name "EsaCure 1") ·Organic particles: 0.6 parts by mass (Acrylic beads, average particle size 2.2 μm, refractive index 1.559, coefficient of variation: 10.4%) • Fumed silica: 1 part by mass (Octylsilane treatment, average particle size 12nm, Nippon Aerosil Co., Ltd.) Leveling agent: 0.5 parts by mass (Dainichi Seika Kogyo Co., Ltd., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0177] (4) Coating liquid 4 for uneven layer The following materials were diluted with a mixed solvent of toluene, 2-propanol, and cyclohexanone in a mass ratio of 60:10:30 to achieve a solid content concentration of 40% by mass, to prepare coating solution 4 for uneven layers. <Materials for coating liquid 4 for uneven layers> Pentaerythritol tetraacrylate: 45 parts by mass (Product name: PETA, Daicel Sci-Tec Corporation) • Urethane acrylate oligomer: 55 parts by mass (Mitsubishi Chemical Corporation, product name "UV-1700B", solid content 100% by mass) · Photoinitiator: 3 parts by mass (IGM Resins B.V., product name "Esacure 1") · Fumed silica: 0.5 parts by mass (Octylsilane treatment, average particle size 12 nm, Nippon Aerosil Co., Ltd.) · Fumed silica: 0.2 parts by mass (Methylsilane treatment, average particle size 12 nm, Nippon Aerosil Co., Ltd.) · Levelling agent: 0.5 parts by mass (Dainichi Seika Chemicals Co., Ltd., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0178] (5) Coating liquid 5 for uneven layer The following materials were diluted with a mixed solvent of toluene, 2-propanol and cyclohexanone in a mass ratio of 60:10:30 so that the solid content concentration became 40% by mass to prepare coating liquid 5 for uneven layer. <Materials of coating liquid 5 for uneven layer> · Pentaerythritol tetraacrylate: 45 parts by mass (Product name: PETA, Daicel Cytec Co., Ltd.) · Urethane acrylate oligomer: 55 parts by mass (Mitsubishi Chemical Corporation, product name "UV-1700B", solid content 100% by mass) · Photoinitiator: 3 parts by mass (IGM Resins B.V., product name "Esacure 1") · Organic particles: 3 parts by mass (Acrylic beads, average particle size 2.3 μm, refractive index 1.559, coefficient of variation: 10.2%) · Fumed silica: 1 part by mass (Octylsilane treatment, average particle size 12 nm, Nippon Aerosil Co., Ltd.) · Levelling agent: 0.5 parts by mass (Dainichi Seika Chemicals Co., Ltd., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0179] (6) Coating liquid 6 for uneven layer The following materials were diluted with a mixed solvent of toluene, 2-propanol, and cyclohexanone at a mass ratio of 60:10:30 so that the solid content concentration became 40% by mass to prepare a coating liquid 6 for the uneven layer. <Materials for Coating Liquid 6 for Uneven Layer> · Pentaerythritol tetraacrylate: 45 parts by mass (Product name: PETA, manufactured by Daicel Cytec Co., Ltd.) · Urethane acrylate oligomer: 55 parts by mass (Mitsubishi Chemical Corporation, product name "UV-1700B", solid content 100% by mass) · Photoinitiator: 3 parts by mass (IGM Resins B.V., product name "Esacure 1") · Organic particles: 10 parts by mass (Acrylic beads, average particle size 3.0 μm, refractive index 1.559, coefficient of variation: 9.8%) · Levelling agent: 0.5 parts by mass (Dainichi Seika Chemicals Co., Ltd., product name "Seika Beam 10-28(TL)", solid content 10% by mass)

[0180] (7) Coating Liquid 7 for Uneven Layer The following materials were diluted with a mixed solvent of toluene, 2-propanol, and cyclohexanone at a mass ratio of 60:10:30 so that the solid content concentration became 40% by mass to prepare a coating liquid 7 for the uneven layer. <Materials for Coating Liquid 7 for Uneven Layer> · Pentaerythritol tetraacrylate: 45 parts by mass (Product name: PETA, manufactured by Daicel Cytec Co., Ltd.) · Urethane acrylate oligomer: 55 parts by mass (Mitsubishi Chemical Corporation, product name "UV-1700B", solid content 100% by mass) · Photoinitiator: 3 parts by mass (IGM Resins B.V., product name "Esacure 1") · Organic particles: 15 parts by mass (Acrylic beads, average particle size 3.6 μm, refractive index 1.559, coefficient of variation: 10.5%) ·Metal coated particles: 0.5 part by mass (Nickel-coated acrylic beads, average particle size 4.5 μm) Leveling agent: 0.5 parts by mass (Dainichi Seika Kogyo Co., Ltd., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0181] (8) Coating liquid for uneven layer 8 The following materials were diluted with a mixed solvent of 4-methyl-2-pentanone and 2-propanol in a mass ratio of 70:30 to achieve a solid content concentration of 40% by mass, to prepare coating solution 8 for uneven layers. <Materials for coating solution 8 for uneven layers> Pentaerythritol triacrylate: 100 parts by mass (Product name: PET-30, Nippon Kayaku Co., Ltd.) • Photopolymerization initiator: 3 parts by mass (IGM Resins BV, product name "EsaCure 1") ·Metal coated particles: 0.6 parts by mass (Nickel-coated acrylic beads, average particle size 4.5 μm) Leveling agent: 0.5 parts by mass (Dainichi Seika Kogyo Co., Ltd., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0182] (9) Coating liquid 9 for uneven layer The following materials were diluted with a mixed solvent of 4-methyl-2-pentanone and 2-propanol in a mass ratio of 70:30 to achieve a solid content concentration of 40% by mass, to prepare coating solution 9 for uneven layers. <Materials for coating solution 9 for uneven layers> Pentaerythritol triacrylate: 100 parts by mass (Product name: PET-30, Nippon Kayaku Co., Ltd.) • Photopolymerization initiator: 3 parts by mass (IGM Resins BV, product name "EsaCure 1") Leveling agent: 0.5 parts by mass (Dainichi Seika Kogyo Co., Ltd., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0183] (10) Coating liquid 10 for uneven layer The following materials were diluted with a mixed solvent of toluene and cyclohexanone at a mass ratio of 70:30 so that the solid content concentration became 40% by mass to prepare the coating liquid 10 for uneven layer. <Materials of coating liquid 10 for uneven layer> · Pentaerythritol tetraacrylate: 45 parts by mass (Product name: PETA, manufactured by Daicel Cytec Co., Ltd.) · Urethane acrylate oligomer: 55 parts by mass (Mitsubishi Chemical Corporation, product name "UV-1700B", solid content 100% by mass) · Photoinitiator: 3 parts by mass (IGM Resins B.V., product name "Esacure 1") · Organic particles: 15 parts by mass (Acrylic beads, average particle size 3.6 μm, refractive index 1.559, coefficient of variation: 10.5%) · Levelling agent: 0.5 parts by mass (Dainippon Ink and Chemicals, Inc., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0184] (11) Coating liquid 11 for uneven layer The following materials were diluted with a mixed solvent of toluene and cyclohexanone at a mass ratio of 70:30 so that the solid content concentration became 40% by mass to prepare the coating liquid 11 for uneven layer. <Materials of coating liquid 11 for uneven layer> · Pentaerythritol tetraacrylate: 45 parts by mass (Product name: PETA, manufactured by Daicel Cytec Co., Ltd.) · Urethane acrylate oligomer: 55 parts by mass (Mitsubishi Chemical Corporation, product name "UV-1700B", solid content 100% by mass) · Photoinitiator: 3 parts by mass (IGM Resins B.V., product name "Esacure 1") · Organic particles: 0.5 parts by mass (Acrylic beads, average particle size 3.6 μm, refractive index 1.559, coefficient of variation: 10.5%) Leveling agent: 0.5 parts by mass (Dainichi Seika Kogyo Co., Ltd., product name "Seika Beam 10-28 (TL)", solid content 10% by mass)

[0185] (12) Coating liquid for antifouling layer The following materials were diluted with a mixed solvent of methyl isobutyl ketone, methyl ethyl ketone, and propylene glycol monomethyl ether acetate in a mass ratio of 40:30:30 to achieve a solid content concentration of 2.5% by mass, to prepare a coating solution for the antifouling layer. <Materials for antifouling coating solution> • Compound (A): 15 parts by mass (Urethane acrylate oligomer, solid content 100% by mass) ·Fluorine-containing resin composition: 850 parts by mass (Arakawa Chemical Industry Co., Ltd., product name "TU-2362", solid content 10% by mass) • Photopolymerization initiator: 5 parts by mass (IGM Resins BV, product name "Omnirad127") • Hollow silica particles: 100 parts by mass (Average particle size 60 nm, refractive index 1.212) • Solid silica particles: 25 parts by mass (Average particle size 15nm) • Fluorine-based leveling agent: 100 parts by mass (Shin-Etsu Silicone Co., Ltd., product name "X-71-1203M", solids content 20% by mass)

[0186] 4. Preparation and fabrication of PET film, and measurement of in-plane phase difference of PET film. As polyester films for the examples and comparative examples, PET films 1 to 4 described below were prepared, and PET film 5 described below was also prepared. Furthermore, the nx, ny, and nz, as well as the in-plane phase difference (Re), of each PET film were measured using Otsuka Electronics' product name "RETS-100". Table 5 shows the Δn(nx-ny), ΔP, and in-plane phase difference (Re) for each PET film.

[0187] 4-1. PET film 1 <Production of Raw Material (PET(A))> When the temperature of the esterification reaction vessel was raised to reach 200 °C, 86.5 parts by mass of terephthalic acid and 64.5 parts by mass of ethylene glycol were charged. While stirring, 0.020 parts by mass of antimony trioxide, 0.061 parts by mass of magnesium acetate tetrahydrate, and 0.16 parts by mass of triethylamine were charged as catalysts. Then, pressurization and temperature increase were carried out, and after carrying out a pressurized esterification reaction under the conditions of a gauge pressure of 0.34 MPa and 240 °C, the esterification reaction vessel was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Further, the temperature was raised to 260 °C over 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added. Then, after 15 minutes, dispersion treatment was carried out with a high-pressure disperser. Furthermore, an aqueous sodium tripolyphosphate solution was made to contain 0.1% by mass as sodium atoms with respect to silica particles, and the coarse particle portion was cut by 35% by centrifugal separation treatment, and an ethylene glycol slurry of silica particles with an average particle diameter of 2.5 μm that was subjected to filtration treatment with a metal filter having a mesh opening of 5 μm was added at 0.2 parts by mass as the particle content. After 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction vessel, and a polycondensation reaction was carried out under reduced pressure at 280 °C. After the polycondensation reaction was completed, filtration treatment was carried out with a Nylon filter having a 95% cut-off diameter of 5 μm, then extruded in a strand shape from a nozzle, cooled and solidified using cooling water that had been subjected to filtration treatment with a filter having a pore diameter of 1 μm or less in advance, and cut into pellets. The intrinsic viscosity of the obtained polyethylene terephthalate resin (A) was 0.64 dl / g, the oligomer content was 0.96% by mass, and there were substantially no inert particles and internal precipitation particles. Incidentally, "polyethylene terephthalate resin (A)" may be abbreviated as "PET(A)".

[0188] <Production of Raw Material (PET(B))><00010​​​​​​100 parts by mass of PET(B) resin pellets with an intrinsic viscosity of 0.62 dl / g were dried under reduced pressure at 1 Torr for 6 hours at 135°C, and then supplied to extruder 2 for the intermediate layer II. PET(A) and PET(B) were mixed and adjusted to have a silica particle content of 0.10% by mass, dried by conventional methods, and then supplied to extruder 1 for the outer layer I and outer layer III. The silica particles were those contained in PET(A). The PET supplied to extruders 1 and 2 was melted at 288°C. The melted polymers were filtered through stainless steel sintered filter media, laminated in a 2-type 3-layer confluence block, extruded into sheets from a die, and then cooled and solidified using an electrostatic casting method on a casting drum with a surface temperature of 30°C to produce an unstretched film. At this time, the discharge rate of each extruder was adjusted so that the thickness ratio of layers I, II, and III was 5:90:5. The aforementioned stainless steel sintered filter material is a filter material with a "nominal filtration accuracy of cutting 95% of 10μm particles." This unstretched film was heated to 100°C using a heated roll group and an infrared heater, and then stretched 3.0 times in the longitudinal direction using a roll group with different peripheral speeds to obtain a uniaxially oriented PET film. Next, the uniaxially oriented film was guided to a tenter stretcher, and while holding the ends of the film with clips, it was guided into a hot air zone at a temperature of 140°C and stretched to 3.2 times its original width. Then, while maintaining the width stretched in the width direction, it was guided into a hot air zone at a temperature of 210°C and stretched to 1.1 times its original width in this hot air zone. After further heat treatment in the 210°C hot air zone for about 5 seconds, a 3% relaxation treatment was performed in the width direction to obtain a biaxially oriented PET film (PET film 1) with a film thickness of approximately 40 μm.

[0190] 4-2. PET film 2 A biaxially oriented PET film 2 was obtained in the same manner as PET film 1, except that the stretching ratio in the longitudinal direction was changed to 3.5 times, the stretching ratio in the first stage in the width direction was changed to 3.6 times, and the stretching ratio in the second stage in the width direction was changed to 1.2 times.

[0191] 4-3. PET film 3 A biaxially oriented PET film 3 was obtained in the same manner as PET film 1, except that the stretching ratio in the longitudinal direction was changed to 3.9 times, the stretching ratio in the first stage in the width direction was changed to 3.7 times, the temperature during the second stage of stretching in the width direction was changed to 220°C, the stretching ratio in the second stage in the width direction was changed to 1.2 times, and the temperature during the relaxation treatment was changed to 220°C.

[0192] 4-4. PET film 4 Referring to Japanese Patent Publication No. 2018-112635, a biaxially oriented PET film with a thickness of 25 μm was prepared according to Example 9 of the said publication. This PET film was designated as PET film 4.

[0193] 4-5. PET film 5 As PET film 5, we prepared a commercially available biaxially oriented PET film (product name "Cosmoshine A4100" manufactured by Toyobo Co., Ltd., with a thickness of 38 μm and an easy-adhesion layer on one side).

[0194] 4-6. PET film 6 A biaxially oriented PET film 6 was obtained in the same manner as PET film 1, except that the first stretching ratio in the width direction was changed to 3.5 times.

[0195] 4-7. PET film 7 A biaxially oriented PET film 7 was obtained in the same manner as PET film 1, except that the first stretching ratio in the width direction was changed to 3.4 times.

[0196] 4-8. PET film 8 A biaxially oriented PET film 8 was obtained in the same manner as PET film 1, except that the stretching ratio in the longitudinal direction was changed to 3.1 times and the second stretching ratio in the width direction was changed to 1.2 times.

[0197] 4-9. PET film 9 A biaxially oriented PET film 9 was obtained in the same manner as PET film 1, except that the stretching ratio in the longitudinal direction was changed to 4.0 times, the stretching ratio in the first stage in the width direction was changed to 3.7 times, the temperature during the second stage of stretching in the width direction was changed to 220°C, the stretching ratio in the second stage in the width direction was changed to 1.2 times, and the temperature during the relaxation treatment was changed to 220°C.

[0198] 5. Fabrication of Optical Laminate 5-1. Optical Laminate Using PET Film 1 [Example 1] On PET film 1 (refer to the above "4". ΔP: 0.150, nx - ny: 0.125, Re: 500 nm), the following coating solution 1 for an easy - adhesion layer was applied so that the wet mass was 5 g / m 2 and dried at 70°C for 30 seconds to form an easy - adhesion layer with a dry mass of 0.5 g / m 2 . Next, on the easy - adhesion layer, the coating solution 2 for a concavo - convex layer was applied so that the wet mass was 12.5 g / m 2 (dry mass 5 g / m 2 ) and dried at 70°C for 30 seconds, and then irradiated with ultraviolet light of 100 mJ / cm 2 to form a concavo - convex layer with a dry thickness of 5 μm. Next, on the concavo - convex layer, the coating solution for an antifouling layer was applied so that the wet mass was 4 g / m 2 (dry mass 0.1 g / m 2 ) and dried at 60°C for 30 seconds, and then irradiated with ultraviolet light of 200 mJ / cm 2 to form an antifouling layer with a dry thickness of 100 nm, and the optical laminate of Example 1 was obtained. [[ID=二十九]]<Coating Solution 1 for Easy - Adhesion Layer> A coating solution obtained by mixing 33 parts by mass of a polyester resin (trade name "Vylon UR - 1400" of Toyobo Co., Ltd.) and 1 part by mass of a cross - linking agent (trade name "Takenate D110N" of Mitsui Chemicals, Inc.) and diluting it to a solid content of 10% by mass with a mixed solvent having a mass ratio of methyl ethyl ketone to toluene of 8:2.

[0199] Regarding the optical laminate of Example 1, the wet masses of the concavo - convex layer and the antifouling layer; the drying conditions of the concavo - convex layer and the antifouling layer; the ultraviolet irradiation conditions of the concavo - convex layer and the antifouling layer; the dry thicknesses of the concavo - convex layer and the antifouling layer; etc. are taken as Fabrication Method 1. That the item "Fabrication Method" in Tables 1 - 4 is "1" means that the optical laminate of Example 1 and the above - mentioned manufacturing conditions are the same.

[0200] [Examples 2 - 5] Optical laminates of Examples 2 to 5 were obtained in the same manner as in Example 1, except that the coating liquid 2 for the uneven layer was changed to one of those listed in Table 1.

[0201] [Example 6] On the PET film 1 (see "4" above), apply the above-mentioned easy-adhesion layer coating liquid 1 at a wet mass of 5 g / m². 2 Apply the mixture as shown, dry at 70°C for 30 seconds, and dry to a mass of 0.5 g / m². 2 An easily adhesive layer was formed. Next, the coating liquid 3 for uneven layers is applied to the easy-adhesion layer at a wet mass of 2.5 g / m². 2 (Dry mass 1g / m 2 Apply the mixture so that it becomes ), dry at 70°C for 30 seconds, and expose to UV light at 100 mJ / cm². 2 Irradiation was performed to form a textured layer with a dry thickness of 1 μm. Next, a coating liquid for the anti-fouling layer is applied to the uneven surface at a wet mass of 4 g / m². 2 (Dry mass 0.1g / m 2 Apply the mixture so that it becomes ), dry at 60°C for 30 seconds, and expose to UV light at 200 mJ / cm². 2 Irradiation was performed to form an antifouling layer with a dry thickness of 100 nm, and the optical laminate of Example 6 was obtained. The manufacturing conditions for the optical laminate of Example 6, including the wet mass of the textured layer and the antifouling layer; the drying conditions of the textured layer and the antifouling layer; the ultraviolet irradiation conditions of the textured layer and the antifouling layer; and the dry thickness of the textured layer and the antifouling layer, are defined as Manufacturing Method 2.

[0202] [Comparative Examples 1-2, 4-7] Optical laminates of Comparative Examples 1-2 and 4-7 were obtained in the same manner as in Example 1, except that the coating liquid 2 for the uneven layer was changed to one of those listed in Table 1.

[0203] [Comparative Example 3] On the PET film 1 (see "4" above), apply the above-mentioned easy-adhesion layer coating liquid 1 at a wet mass of 5 g / m². 2 Apply the mixture as shown, dry at 70°C for 30 seconds, and dry to a mass of 0.5 g / m². 2 An easily adhesive layer was formed. Next, the coating liquid 1 for uneven layers is applied to the easy-adhesion layer at a wet mass of 12.5 g / m². 2(Dry mass 5g / m 2 Apply the mixture so that it becomes ), dry at 50°C for 30 seconds, and expose to UV light at 100 mJ / cm². 2 Irradiation was performed to form a textured layer with a dry thickness of 5 μm. Next, a coating liquid for the anti-fouling layer is applied to the uneven surface at a wet mass of 4 g / m². 2 (Dry mass 0.1g / m 2 Apply the mixture so that it becomes ), dry at 60°C for 30 seconds, and expose to UV light at 200 mJ / cm². 2 Irradiation was performed to form an antifouling layer with a dry thickness of 100 nm, and the optical laminate of Comparative Example 3 was obtained. The manufacturing conditions for the optical laminate of Comparative Example 3, including the wet mass of the textured layer and the antifouling layer, the drying conditions of the textured layer and the antifouling layer, the UV irradiation conditions of the textured layer and the antifouling layer, and the dry thickness of the textured layer and the antifouling layer, are defined as Manufacturing Method 3. The "Manufacturing Method" column in Tables 1-4 being "3" indicates that the optical laminate of Comparative Example 3 and the aforementioned manufacturing conditions are identical.

[0204] 5-2. Optical laminate using PET film 2 [Examples 7-12] Optical laminates of Examples 7 to 12 were obtained in the same manner as in Examples 1 to 6, except that PET film 1 was replaced with PET film 2 as described in "4" above.

[0205] [Comparative Examples 8-14] Optical laminates of Comparative Examples 8 to 14 were obtained in the same manner as Comparative Examples 1 to 7, except that PET film 1 was replaced with PET film 2 as described in "4" above.

[0206] 5-3. Optical laminate using PET film 3 [Examples 13-18] Optical laminates of Examples 13 to 18 were obtained in the same manner as in Examples 1 to 6, except that PET film 1 was replaced with PET film 3 as described in "4" above.

[0207] [Comparative Examples 15-21] Optical laminates of Comparative Examples 15 to 21 were obtained in the same manner as Comparative Examples 1 to 7, except that PET film 1 was replaced with PET film 3 as described in "4" above.

[0208] 5-4. Optical laminate with modified antifouling layer thickness [Example 19] An optical laminate of Example 19 was obtained in the same manner as in Example 1, except that the thickness of the antifouling layer was changed to 90 nm. [Example 20] An optical laminate of Example 20 was obtained in the same manner as in Example 1, except that the thickness of the antifouling layer was changed to 110 nm.

[0209] [Table 1]

[0210] [Table 2]

[0211] [Table 3]

[0212] [Table 4]

[0213] From Tables 1 to 4, it can be confirmed that the optical laminates of the examples exhibit excellent adhesion between the polyester film with a high degree of plane orientation ΔP and the easy-adhesion layer, resulting in excellent adhesion of the optical laminate as a whole, and suppression of localized defects.

[0214] 6. Verification of pencil hardness and iridescence 6-1. Fabrication of Optical Stacks [Examples 21-24] Optical laminates of Examples 21 to 24 were obtained in the same manner as in Example 1, except that PET film 1 was replaced with PET films 6 to 9 as described in "4" above.

[0215] [Comparative Example 8] The optical laminate of Comparative Example 8 was obtained in the same manner as in Example 1, except that PET film 1 was replaced with PET film 4 as described in "4" above.

[0216] [Comparative Example 9] An optical laminate of Comparative Example 9 was obtained in the same manner as in Example 1, except that PET film 1 was replaced with PET film 5 as described in "4" above. In the optical laminate of Comparative Example 9, an easy-adhesion layer, an uneven layer, and an anti-fouling layer were formed on the side of PET film 5 that did not have an easy-adhesion layer.

[0217] 6-2. Evaluation The optical laminates obtained in Examples 1, 7, 13, 21-24 and Comparative Examples 8-9 were subjected to the following measurements and evaluations (1) and (2). The results are shown in Table 5.

[0218] (1)Pencil hardness The optical laminates obtained in Examples 1, 7, 13, 21-24 and Comparative Examples 8-9 were heated at 100°C for 10 minutes. The pencil hardness of the heated optical laminates was measured according to the scratch hardness (pencil method) of JIS K 5600-5-4:1999. Specifically, a pencil with a predetermined hardness was applied to the surface of the anti-fouling layer of the optical laminate at a 45° angle to the sample surface, and the pencil hardness was measured by moving it at a speed of 1.4 mm / sec with a load of 500 g. After applying the load to the optical laminate sample, the sample was heated again at 100°C for 10 minutes before visually evaluating the scratches. For each sample, the above procedure was performed three times using pencils of each hardness level. Of the pencils that remained undamaged, the hardest one was identified as the pencil hardness of that sample.

[0219] (2) Rainbow pattern The optical laminates of the examples and comparative examples were placed on the viewing-side polarizing plate of the image display device 1 with the configuration described below, so that the PET film side faced the polarizing plate side. Next, the image display device was turned on in a darkroom environment, and observed from various angles with the naked eye to evaluate the presence or absence of rainbow unevenness according to the following criteria. The evaluators were 20 healthy individuals, 5 from each age group from their 20s to 50s, with corrected visual acuity of 1.0 or higher. The evaluation environment was set to a temperature of 23±5°C and a relative humidity of 40% to 65%. Furthermore, before the start of the evaluation, the target samples were exposed to the aforementioned environment for at least 30 minutes. A: More than 16 people answered that they could not see the rainbow pattern. B: Between 11 and 15 people answered that they could not see the rainbow pattern. C: Fewer than 10 people answered that they could not see the rainbow pattern.

[0220] <Configuration of Image Display Device 1> (1) Display element: Three-color independent organic EL display element with microcavity structure (BT.2020-2 coverage based on CIE-xy chromaticity diagram: 77%). (2) Polarizing plate on the light source side: None (3) Viewing-side polarizer: A polarizer made of PVA and iodine, with TAC film used as a polarizer protective film. The polarizer is positioned so that the direction of its absorption axis is parallel to the horizontal direction of the screen. (4) Size: 10 inches diagonally

[0221] [Table 5]

[0222] Table 4 shows that the optical laminates of the examples using polyester films that satisfy formulas 1-1 and 1-2 can suppress rainbow-like unevenness caused by in-plane phase differences and can also achieve good pencil hardness of the optical laminates. [Explanation of Symbols]

[0223] 10 Polyester film 20 Easy adhesive layer 30 Uneven layer 40 Anti-fouling layer 100 Optical laminate

Claims

1. An optical laminate having an easy-adhesion layer, a textured layer, and an anti-fouling layer in that order on a polyester film, When the refractive index in the slow axis direction within the plane of the polyester film is defined as nx, the refractive index in the direction perpendicular to the slow axis within the same plane as ny, and the refractive index in the thickness direction of the polyester film as nz, the polyester film satisfies the following equations 1-2, The polyester film has an in-plane phase difference of 224 nm or more and 1344 nm or less. The aforementioned uneven layer satisfies the following equations 2-1, 2-2, and 2-3, where Ssk is defined as the three-dimensional skewness of the surface elevation of the uneven layer and Sa is defined as the three-dimensional arithmetic mean roughness of the surface of the uneven layer. An optical laminate having a haze of 0.3% or more and 7% or less according to JIS K7136:2000. 0.140 ≤ ΔP (1-2) 1.00 ≤ A ≤ 1.60 (2-1) 0.10 ≤ Ssk ≤ 0.70 (2-2) 0.020μm≦Sa≦0.100μm (2-3) [In equation 1-2, "ΔP" represents "((nx + ny) / 2) - nz".] [In equation 2-1, "A" is "log 10 This represents "(Sa [μm] × 100 / Ssk)," where 0 < Ssk.

2. The optical laminate according to claim 1, wherein the polyester film further satisfies the following formula 1-1. nx-ny≦0.0250 (1-1)

3. The optical laminate according to claim 1 or 2, wherein the thickness of the antifouling layer is 1 nm or more and 200 nm or less.

4. The optical laminate according to any one of claims 1 to 3, wherein the contact angle of the surface of the antifouling layer with respect to pure water is 80 degrees or more.

5. The optical laminate according to any one of claims 1 to 4, wherein the luminous reflectance Y value measured at a light incidence angle of 5 degrees from the side having the anti-fouling layer is 3.0% or less.

6. The optical laminate according to any one of claims 1 to 5, wherein the thickness of the polyester film is 10 μm or more and 75 μm or less.

7. A polarizing plate having a polarizer, a first transparent protective plate disposed on one side of the polarizer, and a second transparent protective plate disposed on the other side of the polarizer, wherein at least one of the first transparent protective plate and the second transparent protective plate is an optical laminate according to any one of claims 1 to 6, and the optical laminate is arranged such that the surface on the anti-fouling layer side faces away from the polarizer.

8. A surface plate for an image display device, comprising an optical laminate bonded to a resin plate or a glass plate, wherein the optical laminate is the optical laminate described in any one of claims 1 to 6, and the optical laminate is arranged such that the surface facing the anti-fouling layer faces away from the resin plate or the glass plate.

9. An image display device in which an optical laminate described in any of claims 1 to 6 is arranged on a display element such that the surface of the antifouling layer facing away from the display element, and the optical laminate is arranged on the surface.

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