Antireflection member, and polarizing plate, image display panel, image display device, and antireflective article using said antireflection member

Abstract

Provided is an antireflection member having favorable scratch resistance. This antireflection member 100 comprises, on a substrate 10, a hard coat layer 20 and a low-refractive-index layer 30 in this order, wherein: the low-refractive-index layer 30 contains a binder component 31 and inorganic particles; the inorganic particles include hollow silica particles 32 and first solid particles 33; in the thickness direction of the low-refractive-index layer 30, the hollow silica particles 32 are unevenly distributed on the hard coat layer 20; and when the average particle diameter of the hollow silica particles 32 is defined as r and the average particle diameter of the first solid particles 33 is defined as R1, r<R1.

Description

Anti-reflective member, and polarizing plate, image display panel, image display device, and anti-reflective article using the anti-reflective member.

[0001] This disclosure relates to an anti-reflective member, and to a polarizing plate, an image display panel, an image display device, and an anti-reflective article using the anti-reflective member.

[0002] In display devices such as liquid crystal displays, organic EL displays, and micro-LED displays, as well as in showcases, anti-reflective materials may be provided on the surface to improve visibility.

[0003] As an anti-reflective member, one having a low refractive index layer on a substrate has been proposed. The low refractive index layer includes, for example, hollow particles for lowering the refractive index and a binder component for holding the hollow particles. Examples of anti-reflective members containing hollow particles in the low refractive index layer are proposed in Patent Documents 1 and 2. The low refractive index layers in Patent Documents 1 and 2 also include solid particles.

[0004] International Publication No. 2012 / 147527, JP 2018-535440

[0005] Anti-reflective materials are used by being placed on the surface of image display devices and the like. Therefore, the surface of the anti-reflective material is rubbed during operations such as touch panel operation and wiping away dirt. Also, anti-reflective materials placed on the display surface of a notebook computer are repeatedly rubbed by contact with the keyboard when the notebook computer is closed and carried. Therefore, excellent scratch resistance is required for anti-reflective materials. Furthermore, in recent years, image display devices have become ultra-high resolution, making scratches on anti-reflective materials more noticeable. For this reason, anti-reflective materials are required to have scratch resistance greater than that of conventional materials. However, conventional anti-reflective materials such as the anti-reflective materials described in Patent Documents 1 and 2 have insufficient scratch resistance.

[0006] The object of this disclosure is to provide an anti-reflective material with good scratch resistance, and a polarizing plate, image display panel, image display device, and anti-reflective article using the same.

[0007] This disclosure provides the following <1> to <5>. <1> An anti-reflective member having a hard coat layer and a low refractive index layer in this order on a substrate, wherein the low refractive index layer comprises a binder component and inorganic particles, the inorganic particles comprising hollow silica particles and first solid particles, the hollow silica particles being biased toward the hard coat layer side in the thickness direction of the low refractive index layer, and r < R1 when the average particle diameter of the hollow silica particles is defined as r and the average particle diameter of the first solid particles is defined as R1. <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 either the first transparent protective plate or the second transparent protective plate is the anti-reflective member described in <1>, and the surface of the anti-reflective member on the low refractive index layer side faces away from the polarizer. <3> An image display panel having a display element and an optical film disposed on the light-emitting surface side of the display element, wherein the optical film includes the anti-reflective member described in <1>, the surface of the anti-reflective member on the low refractive index layer side faces away from the display element, and the anti-reflective member is placed on the outermost surface. <4> An image display device comprising the image display panel described in <3>, with the anti-reflective member placed on the outermost surface. <5> An anti-reflective article having the surface of the anti-reflective member described in <1> on a member facing away from the member, and the anti-reflective member being placed on the outermost surface.

[0008] The anti-reflective member of this disclosure, as well as polarizing plates, image display devices, and anti-reflective articles using the same, can have good scratch resistance.

[0009] This is a schematic cross-sectional view showing one embodiment of the anti-reflective member of the present disclosure. This is a cross-sectional view showing one embodiment of the image display panel of the present disclosure. This is a schematic diagram for explaining procedure (3). This is an example of a superimposed image obtained in procedure (4). (a) is a schematic diagram showing an example of how hollow silica particles are distributed in the low refractive index layer, and (b) is position information (bar graph) obtained by procedure (3) in the distribution of (a). This is a diagram showing an example of a label image.

[0010] Embodiments of the present disclosure will be described below. [Anti-reflective member] The anti-reflective member of the present disclosure has a hard coat layer and a low refractive index layer on a substrate in this order, the low refractive index layer contains a binder component and inorganic particles, the inorganic particles include hollow silica particles and first solid particles, in the thickness direction of the low refractive index layer the hollow silica particles are biased toward the hard coat layer side, and when the average particle diameter of the hollow silica particles is defined as r and the average particle diameter of the first solid particles is defined as R1, r < R1.

[0011] Figure 1 is a schematic cross-sectional view of the cross-sectional shape of the anti-reflective member 100 of the present disclosure. The anti-reflective member 100 in Figure 1 has a hard coat layer 20 and a low refractive index layer 30 on a substrate 10 in that order. The low refractive index layer 30 has a binder component 31, hollow silica particles 32, a first solid particle 33, and a second solid particle 34. As shown in Figure 1, the anti-reflective member of the present disclosure has a region in the thickness direction of the low refractive index layer 30 where the hollow silica particles 32 are unevenly distributed towards the hard coat layer 20. The symbol S in Figure 1 is the region in the thickness direction of the low refractive index layer where the hollow silica particles 32 are unevenly distributed. Hereinafter, the "region in the thickness direction of the low refractive index layer where the hollow silica particles are unevenly distributed" will be referred to as the "region where the hollow silica particles are unevenly distributed". In the anti-reflective member of the present disclosure, the "region where the hollow silica particles are unevenly distributed" is formed by the division of the low refractive index layer into a region where hollow silica particles exist and a region where hollow silica particles do not exist in the thickness direction. In the anti-reflective member of this disclosure, hollow silica particles are densely concentrated in the "regions where hollow silica particles are unevenly distributed (regions where hollow silica particles exist)." Figure 1 is a schematic cross-sectional view. That is, the scales of each layer and each material constituting the anti-reflective member 100 are schematic for ease of illustration and differ from the actual scales. The same applies to Figure 2.

[0012] The anti-reflective member of this disclosure is not limited to the laminated configuration shown in Figure 1. For example, the anti-reflective member of this disclosure may have other layers not shown in Figure 1. Preferred embodiments of the laminated configuration of the anti-reflective member of this disclosure include "a laminated configuration having a hard coat layer and a low refractive index layer on a substrate in that order" and "a laminated configuration having a hard coat layer, a high refractive index layer and a low refractive index layer on a substrate in that order".

[0013] <Substrate> The substrate is preferably light-transmitting, smooth, heat-resistant, and has excellent mechanical strength. Examples of such substrates include plastic films such as polyester, triacetylcellulose (TAC), cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyetherketone, polymethyl methacrylate, polycarbonate, polyurethane, and amorphous olefin (Cyclo-Olefin-Polymer: COP). The substrate may also be made by laminating two or more plastic films. Among the above, polyester films such as polyethylene terephthalate and polyethylene naphthalate are preferred from the viewpoint of mechanical strength and dimensional stability. Among polyester films, stretched films are preferred, and biaxially stretched films are more preferred. TAC and acrylic are preferred from the viewpoint of light transmittance and optical isotropy. COP and polyester are preferred in terms of excellent weather resistance.

[0014] The thickness of the substrate is preferably 5 μm to 300 μm, more preferably 15 μm to 200 μm, and even more preferably 25 μm to 120 μm. If the anti-reflective member is to be made into a thin film, the preferred upper limit of the substrate thickness is 80 μm or less, and the more preferred upper limit is 70 μm or less.

[0015] The thickness of the substrate is measured using a contact-type film thickness gauge. An example of a contact-type film thickness gauge is the Mitutoyo Corporation model number "MDC-25SX". In this specification, the thickness of the substrate refers to the average value of 10 measurements.

[0016] In the constituent elements shown in this specification, if multiple options are provided for both the upper and lower limits of a numerical value, the description shall include embodiments of a range that combines one selected from the upper limit options and one selected from the lower limit options. For example, embodiments of the substrate thickness range include 5 μm to 300 μm, 5 μm to 200 μm, 5 μm to 120 μm, 5 μm to 80 μm, 5 μm to 70 μm, 5 μm to 20 μm, 20 μm to 300 μm, 20 μm to 200 μm, 20 μm to 120 μm, 20 μm to 80 μm, 20 μm to 70 μm, 30 μm to 300 μm, 30 μm to 200 μm, 30 μm to 120 μm, 30 μm to 80 μm, and 30 μm to 70 μm.

[0017] The surface of the substrate may be subjected to physical or chemical treatments, such as corona discharge treatment, or a readily adhesive layer may be formed to improve adhesion. The substrate preferably has a total light transmittance of 70% or more, more preferably 80% or more, and even more preferably 85% or more, according to JIS K7361-1:1997.

[0018] In this specification, various measurements, such as the measurement of the substrate thickness, the measurement of the position of hollow silica particles in the thickness direction of the low refractive index layer, the measurement of the average particle diameter of the hollow silica particles, and the measurement of the average particle diameter of the first solid particles, shall be performed at a temperature of 23 ± 5°C and a relative humidity of 40% to 65%, unless otherwise specified. Before starting each measurement, the target sample shall be exposed to the aforementioned atmosphere for 30 to 60 minutes before measurement.

[0019] <Hard Coat Layer> The anti-reflective member of this disclosure is required to have a hard coat layer between the substrate and the low refractive index layer. The presence of the hard coat layer makes it easier to improve the scratch resistance of the anti-reflective member. Furthermore, the presence of the hard coat layer makes it easier to improve the pencil hardness of the anti-reflective member.

[0020] The hard coat layer preferably contains a cured product of a curable resin composition such as a thermosetting resin composition or an ionizing radiation-curable resin composition as its main component, and more preferably contains a cured product of an ionizing radiation-curable resin composition as its main component. "Main component" means 50% by mass or more of the resin components constituting the hard coat layer, preferably 70% by mass or more, and more preferably 90% by mass or more. Examples of curable resin compositions such as thermosetting resin compositions or ionizing radiation-curable resin compositions are the same as those exemplified in the low refractive index layer described later. The ionizing radiation-curable compound used in the hard coat layer preferably contains a polyfunctional (meth)acrylate compound.

[0021] The surface of the hard coat layer facing the low refractive index layer may be smooth or may have an uneven surface. If the surface of the hard coat layer facing the low refractive index layer has an uneven surface, the uneven surface can be easily reflected on the surface of the anti-reflective member facing the low refractive index layer, making it easier to impart anti-glare properties to the anti-reflective member.

[0022] Means for forming an uneven surface on the low refractive index side of the hard coat layer include adding particles to the hard coat layer and shaping the hard coat layer with an embossing roll or the like. The uneven surface of the hard coat layer preferably has an arithmetic mean roughness Ra of 0.05 μm or more and 0.30 μm or less, as defined in JIS B0601:2013 with a cutoff value of 0.8 mm, and more preferably 0.10 μm or more and 0.20 μm or less.

[0023] When particles are added to the hard coat layer described above to form an uneven surface, the particles can be either organic or inorganic. 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. Examples of inorganic particles include those made of silica, alumina, zirconia, titania, and the like. The shapes of these particles can be spherical, disc-shaped, rugby ball-shaped, or amorphous. A suitable particle to include in the hard coat layer is fumed silica.

[0024] The average particle diameter of the particles contained in the hard coat layer is preferably 30 nm or more at the lower limit, more preferably 40 nm or more, and preferably 150 nm or less at the upper limit, more preferably 140 nm or less. The average particle diameter of the particles contained in the hard coat layer is evaluated using an image of the vertical cross-section of the anti-reflective member. The image of the vertical cross-section of the anti-reflective member is obtained using a section sample prepared by the method described later. The average particle diameter of the particles contained in the hard coat layer is calculated by the following steps E1 to E3. E1: The cross-section of the section sample is imaged with a scanning transmission electron microscope (STEM). The acceleration voltage of the scanning transmission electron microscope is adjusted to 30 kV, and the magnification is adjusted to a range of 100,000x to 300,000x. E2: Ten arbitrary particles contained in the hard coat layer are extracted from the observed image, and the particle diameter of each particle is calculated. The particle diameter of each particle is the distance at which the distance between two arbitrary parallel lines is maximized when the cross-section of the particle is sandwiched between the two lines. E3: Perform the same procedure five times on observation images of the same sample on different screens, and the value obtained from the number average of the particle diameters of a total of 50 particles is taken as the average particle diameter of the particles contained in the hard coat layer.

[0025] The content of the particles is preferably 3.0 parts by mass or more and 7.5 parts by mass or less, more preferably 3.5 parts by mass or more and 7.0 parts by mass or less, and even more preferably 4.0 parts by mass or more and 6.5 parts by mass or less, based on 100 parts by mass of the resin component of the resin composition constituting the hard coat layer.

[0026] The hard coat layer may further contain additives such as a leveling agent, an antistatic agent, an antioxidant, a surfactant, a dispersant, a light stabilizer, and an ultraviolet absorber.

[0027] The lower limit of the average thickness of the hard coat layer is preferably 0.5 μm or more, more preferably 1 μm or more, and the upper limit is preferably 30 μm or less, more preferably 10 μm or less. By setting the average thickness of the hard coat layer within the above range, it is possible to improve the scratch resistance and easily suppress the generation of cracks during processing such as cutting.

[0028] In this specification, the average thickness of the hard coat layer is calculated by selecting any 20 locations in the image of the vertical cross-section of the antireflection member by a scanning transmission electron microscope and taking the average value of the thicknesses at the 20 locations.

[0029] <Low refractive index layer> The antireflection member of the present disclosure needs to include a low refractive index layer on the hard coat layer. By having a low refractive index layer, the reflection of the antireflection member can be suppressed. The low refractive index layer is preferably located on the surface of the antireflection member. The surface means the surface of the antireflection member having the hard coat layer and the low refractive index layer with respect to the base material. In this specification, the "low refractive index layer" means a layer having a lower refractive index than other layers constituting the antireflection member such as the base material and the hard coat layer. In this specification, the refractive index means the value at a wavelength of 589.3 nm.

[0030] The lower limit of the refractive index of the low refractive index layer is preferably 1.10 or more, more preferably 1.20 or more, still more preferably 1.26 or more, still more preferably 1.28 or more, still more preferably 1.30 or more, and the upper limit is preferably 1.48 or less, more preferably 1.45 or less, still more preferably 1.40 or less, still more preferably 1.38 or less, still more preferably 1.35 or less.

[0031] The low refractive index layer needs to contain a binder component and inorganic particles. Further, the low refractive index layer needs to contain hollow silica particles and first solid particles as the inorganic particles.

[0032] 《Hollow Silica Particles》 Hollow silica particles have an outer shell layer of a silica component, the interior of the particles surrounded by the outer shell layer is a cavity, and the particles contain air inside the cavity. Hollow silica particles are particles whose refractive index decreases in proportion to the porosity. By including hollow silica particles in the low refractive index layer, the refractive index of the low refractive index layer can be lowered.

[0033] The hollow silica particles can lower the refractive index. Therefore, in a normal design, in the thickness direction of the low refractive index layer, the hollow silica particles are evenly dispersed or unevenly distributed on the side opposite to the hard coat layer of the low refractive index layer. However, since hollow silica particles have a cavity inside the particles, they tend to break easily when stress is applied due to rubbing or the like. Therefore, in a normal design, it has been difficult to improve the scratch resistance of an antireflection member having a low refractive index layer containing hollow silica particles. The antireflection member of the present disclosure has the hollow silica particles unevenly distributed on the hard coat layer side in the thickness direction of the low refractive index layer. By unevenly distributing the hollow silica particles on the hard coat layer side, the antireflection member of the present disclosure can make the hollow silica particles less likely to break even when the surface of the low refractive index layer is scratched, and thus the scratch resistance can be improved.

[0034] In the antireflection member 100 of FIG. 1, in the thickness direction of the low refractive index layer 30, the hollow silica particles 32 are unevenly distributed on the hard coat layer 20 side. The symbol S in FIG. 1 indicates the region where the hollow silica particles 32 are unevenly distributed in the thickness direction of the low refractive index layer 30. Whether the hollow silica particles are unevenly distributed on the hard coat layer side in the thickness direction of the low refractive index layer is determined by an image of the vertical cross section of the antireflection member. More specifically, it is determined in the following steps 1 to 3.

[0035] Step 1: An image of the vertical cross-section of the anti-reflective material is captured using a scanning transmission electron microscope. Step 2: From the first image, the "side of the low refractive index layer on the hard coat layer side", the "region where hollow silica particles exist" in the thickness direction, the "region where hollow silica particles do not exist" in the thickness direction, and the "side of the low refractive index layer opposite to the hard coat layer" are determined. Also, for the first image, the ratio of the thickness of the region where hollow silica particles exist to the thickness of the low refractive index layer is calculated. Step 3: The same process as in Steps 1 and 2 is performed for the second to tenth images. The average value is calculated using the ratios of the eight images obtained by excluding the maximum and minimum values ​​from the aforementioned thickness ratios for the ten images. The average value is considered to be the "ratio of the thickness of the region where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer". If the "ratio of the thickness of the region where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer" is 0.90 or less, it is determined that the hollow silica particles are unevenly distributed to the hard coat layer side in the thickness direction of the low refractive index layer.

[0036] -Step 1- In Step 1, an image of the vertical cross-section of the anti-reflective member is taken by preparing a section sample in which the vertical cross-section of the anti-reflective member is exposed, and then imaging using the sample.

[0037] The section samples used in step 1 are prepared by the following procedure. (A1) Cut strips measuring 2 mm in length and 8 mm in width are cut from the anti-reflective material, and then embedded samples are prepared by embedding the cut samples in resin. The resin used for embedding is epoxy resin. The cut samples were taken from an arbitrary location selected from an area excluding a 1 cm area from the edge of the anti-reflective material on which each layer (hard coat layer, low refractive index layer, etc.) is appropriately coated on the substrate. The embedded samples are obtained by placing the cut samples in a silicone embedding plate, pouring in the embedding resin, and then, after the embedding resin has hardened, removing the cut samples and the embedding resin surrounding them from the silicone embedding plate. The shape of the embedded samples is block-shaped. (A2) Section samples are prepared by cutting the block-shaped embedded samples with a diamond knife. As described above, sections cut from a block-shaped embedded sample that are free of defects such as holes and have a uniform thickness of 40 nm to 100 nm are used as the measurement sample.

[0038] In step 1, a grayscale image of the section sample is acquired using a scanning transmission electron microscope. The grayscale image shall include at least the space of the sample chamber of the scanning transmission electron microscope, the low refractive index layer, and the layer adjacent to the lower side of the low refractive index layer. Furthermore, the image is acquired so that the interface of each layer is approximately parallel to the vertical edges of the image. The imaging conditions using the scanning transmission electron microscope are adjusted to the following range: Acceleration voltage: 30 kV Magnification: 100,000x

[0039] -Step 2- In Step 2, the captured image (first image) is used to determine the "side of the low refractive index layer facing the hard coat layer," the "region where hollow silica particles do not exist," the "region where hollow silica particles exist," and the "side of the low refractive index layer opposite to the hard coat layer." Furthermore, for the first image, the ratio of the thickness of the region where hollow silica particles exist to the thickness of the low refractive index layer is calculated.

[0040] When a low refractive index layer is formed directly on a hard coat layer, the interface between the hard coat layer and the low refractive index layer corresponds to the "side of the low refractive index layer facing the hard coat layer." When a high refractive index layer and a low refractive index layer are formed in that order on a hard coat layer, the interface between the high refractive index layer and the low refractive index layer corresponds to the "side of the low refractive index layer facing the hard coat layer." In Figure 1, the symbol X1 corresponds to the "side of the low refractive index layer facing the hard coat layer." The locations where hollow silica particles exist in the low refractive index layer can be identified by extracting the contours of the hollow silica particles from the image. In this way, by extracting the contours of the hollow silica particles from the image, it is possible to distinguish between "regions where hollow silica particles exist in the thickness direction" and "regions where hollow silica particles do not exist in the thickness direction." In Figure 1, the region in the thickness direction enclosed by the symbol S corresponds to "regions where hollow silica particles exist in the thickness direction," and the region in the thickness direction not enclosed by the symbol S corresponds to "regions where hollow silica particles do not exist in the thickness direction." The "side of the low refractive index layer opposite the hard coat layer" refers to the side of the low refractive index layer opposite the hard coat layer, out of the two sides in the thickness direction of the low refractive index layer. In Figure 1, the symbol X2 corresponds to the "side of the low refractive index layer opposite the hard coat layer."

[0041] The determination of "the hard coat side of the low refractive index layer," "the region where hollow silica particles do not exist," "the region where hollow silica particles exist," and "the side of the low refractive index layer opposite the hard coat layer," and the calculation of the ratio of the thickness of the region where hollow silica particles exist to the thickness of the low refractive index layer, are performed by the following procedure. Image analysis software is used for the determination. <Determination Procedure> (1) Create a corrected image from the first image. Analyze the corrected image to determine "the side of the low refractive index layer opposite the hard coat layer." (2) Analyze the corrected image to obtain an extracted image in which the region corresponding to the hollow silica particles that are fully visible among the particles contained in the image is extracted. (3) Subdivide the extracted image into multiple sections in the thickness direction of the low refractive index layer and in the direction perpendicular to the thickness direction. Then, for each section in the thickness direction, calculate the number of sections corresponding to the region of hollow silica particles that appear in the direction perpendicular to the thickness direction. (4) Create a superimposed image by incorporating the acquired coordinates in the thickness direction and the information of the number of sections corresponding to the region of hollow silica particles into the extracted image. In the superimposed image, the "side of the hard coat layer of the low refractive index layer" is determined to identify the low refractive index layer. Next, in the low refractive index layer of the superimposed image, the "regions where hollow silica particles do not exist" and the "regions where hollow silica particles exist" are identified. (5) Using the coordinates Y1 to Y3 obtained in the process of steps (1) to (4), the ratio of the thickness of the region where hollow silica particles exist to the thickness of the low refractive index layer is obtained.

[0042] The following describes more detailed embodiments of the above procedures (1) to (5). -Procedure (1)- The first image is imported into image analysis software and Gaussian filtering is performed. Next, two thresholds for trinarizing the image after Gaussian filtering are calculated using the multi-Otsu method. Note that analysis using the multi-Otsu method is disclosed in Journal of Information Science and Engineering 17 (5): 713-727, 2001. In the first image, the region in the direction opposite to the low refractive index layer, using the "surface opposite to the hard coat layer of the low refractive index layer" as a reference, corresponds to the space of the sample chamber of the scanning transmission electron microscope. In the first image, the region corresponding to the space of the sample chamber has the highest brightness. Therefore, using the threshold with the higher brightness of the two obtained thresholds, the image after Gaussian filtering is converted into a two-tone image. In the two-tone image, the coordinates of the pixels corresponding to the "surface opposite to the hard coat layer of the low refractive index layer" are obtained. The origin of the coordinates is the upper left corner of the first image. The X-axis is the direction parallel to the top edge of the first image from the origin, and the Y-axis is the direction parallel to the left edge of the first image from the origin. On the X-axis, the right direction is considered the positive direction of the X-axis. On the Y-axis, the downward direction is considered the positive direction of the Y-axis. The acquired coordinates are fitted with a linear function in the direction in which the "surface opposite the hard coat layer of the low refractive index layer" extends. The line obtained by the fitting is determined to be the "surface opposite the hard coat layer of the low refractive index layer". Next, the inclination angle of the "surface opposite the hard coat layer of the low refractive index layer" with respect to the direction parallel to the top edge (X-axis) of the first image is obtained. If the absolute value of the obtained inclination angle is within 2 degrees, the first image is imported into the image analysis software again. Next, the obtained inclination angle is input into the image analysis software, and the first image is rotated so that the inclination angle becomes 0 degrees. At this time, the image scale is not changed. The first image after rotation is called the "corrected image". For the corrected image, the above process is performed again to determine the "side opposite the hard coat layer of the low refractive index layer." Also, the coordinates of the intercept between the left edge (Y-axis) of the corrected image and the "side opposite the hard coat layer of the low refractive index layer" are obtained. The coordinates of the intercept here are rounded to an integer.For the corrected image, perform steps (2) to (5) described below. Images with an absolute value of the acquired tilt angle exceeding 2 degrees are excluded from the "determination of whether hollow silica particles are unevenly distributed on the hard coat layer side" without performing steps (2) to (5) described below. In this case, perform step (1) again, using the STEM image obtained using a cut sample taken from a different part of the anti-reflective material in step 1 as the first image.

[0043] -Procedure (2)- The corrected image obtained in Procedure (1) is imported into image analysis software to enhance contrast. Next, Gaussian filtering is performed. The Canny method is applied to the image after Gaussian filtering to detect contour lines corresponding to hollow silica particles in the image. The detected contour lines are shown in white on the image. Fill Hole processing is performed on the contour lines extracted through the Canny method. Fill Hole processing determines the area enclosed by the contour lines and fills that area with white. Particles that cannot be seen entirely in the image are not determined to be in an area enclosed by contour lines and are therefore not filled with white. Particles that cannot be seen entirely refer to particles that are partially missing, for example, when they are located behind other particles in the image or at the edge of the image. The image after processing with the Canny method and Fill Hole processing is a binarized image in which the areas corresponding to hollow silica particles are mainly white and the other areas are black. From the areas displayed in white after the above processing, those with a roundness exceeding 0.8 are further extracted. For example, if a low refractive index layer is formed directly on the hard coat layer, particles in the hard coat layer may be extracted during the operations up to the Fill Hole processing. The particles contained in the hard coat layer are often amorphous particles such as fumed silica. Therefore, by extracting areas with a roundness exceeding 0.8, the particles contained in the hard coat layer can be excluded. Furthermore, a process may be performed to extract only areas whose diameter is within a predetermined range. In this disclosure, the average particle diameter of the first solid particles is larger than the average particle diameter of the hollow silica particles. Even if areas corresponding to the first solid particles are extracted by the Canny method processing and Fill Hole processing, the areas corresponding to the first solid particles can be excluded from the extraction target by performing the above processing. The diameter threshold can be set considering the upper limit of the average particle diameter of the hollow silica particles, as described later. The above operation yields an image (hereinafter referred to as the "extracted image") in which the region corresponding to the hollow silica particles that are fully visible among the particles contained in the image is extracted.

[0044] -Procedure (3)- Based on the "side of the low refractive index layer opposite to the hard coat layer" obtained in Procedure (1), the thickness direction of the low refractive index layer in the extracted image obtained in Procedure (2) (hereinafter sometimes simply referred to as the "thickness direction") is identified. The extracted image is subdivided into multiple sections in each direction, both the thickness direction and the direction perpendicular to the thickness direction (hereinafter simply referred to as the "orthogonal direction"). The number of sections corresponds to the number of pixels in the image. For example, the thickness direction and the orthogonal direction may be subdivided into 1 pixel sections, or into 2 or more pixels sections. The smaller the number of pixels (the larger the number of sections), the higher the accuracy of determining the "side of the low refractive index layer on the hard coat layer side," the "region where hollow silica particles do not exist," and the "region where hollow silica particles exist," which will be described later. Next, an integer is assigned to the left edge of the extracted image according to the sections in the thickness direction. This integer corresponds to a coordinate. Next, for each section in the thickness direction, the number of sections corresponding to the region of hollow silica particles that appears in the orthogonal direction is calculated. The coordinate information and the number of regions corresponding to hollow silica particles obtained through this process correspond to information regarding the position of the hollow silica particles in the thickness direction. Hereafter, this information will be referred to as "position information."

[0045] The above procedure (3) will be explained with reference to Figure 3. Figure 3(a) corresponds to the extracted image obtained in procedure (2). The vertical direction of the extracted image in Figure 3(a) corresponds to the thickness direction of the low refractive index layer. The extracted image contains two regions corresponding to hollow silica particles (regions shown in white). In Figure 3(a), the image is subdivided into 10 sections in the thickness direction (sections A to J from the top edge of the image) and 15 sections in the orthogonal direction. The top left corner of the image is set as 0, and integers (1 to 9 in Figure 3(a)) are assigned as coordinates to the boundaries of each section, starting from the top left corner of the image. An integer corresponding to the number of sections (10 in Figure 3(a)) is assigned to the bottom left corner of the image. Note that the number of sections in Figure 3(a) is reduced for the sake of simplicity. The actual number of sections in the extracted image is much larger than in Figure 3(a). Also, for the sake of understanding, sections A to J are shown on the right side of the image in Figure 3(a). For the image in Figure 3(a), the number of sections corresponding to hollow silica particles, i.e., the number of white sections, is calculated for each section A to J. For example, in section B, the number of white sections calculated in the direction perpendicular to the thickness direction is 2. In section E, the number of white sections calculated in the direction perpendicular to the thickness direction is 10 (6 sections corresponding to the particles on the left, and 4 sections corresponding to the particles on the right). Through the above process, "position information" is obtained. Figure 3(b) is an example of the position information, a bar graph with the vertical axis representing the coordinates in the thickness direction and the horizontal axis representing the number of sections corresponding to hollow silica particles. For understanding, sections A to J are shown on the right side of the image in Figure 3(b). "Position information" is not limited to a graph like Figure 3(b), but may also be a table or other representation that correlates coordinates with the number of sections in the direction perpendicular to the thickness.

[0046] -Procedure (4)- The position information obtained in procedure (3) is incorporated into the extracted image obtained in procedure (2). Specifically, an image (hereinafter referred to as the "overlay image") is obtained by superimposing the bar graph exemplified in Figure 3(b) above with the extracted image. Note that even with extraction by roundness performed in procedure (2), particles contained in the hard coat layer may be extracted. Therefore, in the overlay image, an operation may be performed to exclude from the extraction target areas that are visually determined to be irregular in shape among the areas displayed in white. By performing this operation, the accuracy of determining the "side of the hard coat layer on the low refractive index layer" can be improved.

[0047] Figure 4 shows a superimposed image obtained by incorporating the positional information shown in Figure 3(b) into the extracted image obtained in procedure (2). In Figure 4, the values ​​at the left end (Y-axis) are the coordinates in the thickness direction when the area is divided into 1-pixel sections. The values ​​at the bottom end (X-axis) are the number of sections corresponding to the hollow silica particles when the area is divided into 1-pixel sections in a direction perpendicular to the thickness direction. The dotted line in Figure 4 represents the "surface opposite the hard coat layer of the low refractive index layer." Above the dotted line corresponds to the space of the sample chamber of the scanning transmission electron microscope. As shown in the superimposed image, the number of sections is 0 in the area corresponding to the space of the sample chamber of the scanning transmission electron microscope. In the area corresponding to the low refractive index layer, moving in the thickness direction from the "surface opposite the hard coat layer of the low refractive index layer" reveals sections corresponding to hollow silica particles (the number of sections exceeds 0), and further moving, a location appears where the number of sections is maximum within the low refractive index layer. Because hollow silica particles are densely present within the low refractive index layer, the number of sections in the area corresponding to the low refractive index layer in the image is continuously 1 or greater and never 0. On the other hand, layers adjacent to the lower side of the low refractive index layer, such as the hard coat layer and the high refractive index layer, do not contain hollow silica particles. Therefore, when the hollow silica particles are extracted in step (2), the number of sections corresponding to the hollow silica particles is basically 0 in the layers adjacent to the lower side of the low refractive index layer. Consequently, in the superimposed image, there is a continuous sequence of sections with 1 or more sections in the thickness direction starting from the "side of the low refractive index layer opposite the hard coat layer," and the boundary between the last section where the number of sections in the orthogonal direction exceeds 0 and the section adjacent to this section on the hard coat layer side where the number of sections in the orthogonal direction is 0 corresponds to the "side of the low refractive index layer on the hard coat layer side." The coordinates corresponding to the boundary between the last section where the number of sections in the orthogonal direction exceeds 0, as identified above, and the section adjacent to this section on the hard coat layer side where the number of sections in the orthogonal direction is 0 are obtained. These coordinates can be said to be the coordinates of the intercept between the left edge of the superimposed image and the "side of the low refractive index layer on the hard coat layer side." The obtained coordinates are fitted with a linear function in the direction in which the "side of the low refractive index layer opposite the hard coat layer" extends. The line obtained through fitting is determined to be the "side of the hard coat layer of the low refractive index layer."The "side of the low refractive index layer facing the hard coat layer" is represented by a dashed line in Figure 4. Step (2) excludes particles in the layer adjacent to the lower side of the low refractive index layer. Therefore, in the thickness direction, there is a region where the number of orthogonal regions is zero between the region corresponding to the low refractive index layer and the region from which particles were extracted in the layer below the low refractive index layer. Thus, according to the definition above, the "side of the low refractive index layer facing the hard coat layer" can be detected. The region between the "side of the low refractive index layer facing the hard coat layer" and the "side of the low refractive index layer opposite to the hard coat layer" obtained in step (1) is identified as the low refractive index layer.

[0048] Within the low refractive index layer, obtain the maximum number N of compartments corresponding to hollow silica particles. Set the threshold at 7.5% of the maximum N (i.e., 0.075 N). Next, when moving in the thickness direction of the low refractive index layer from the "side of the low refractive index layer opposite the hard coat layer", obtain the coordinates corresponding to the boundary between the compartment where the number of compartments corresponding to hollow silica particles first exceeds the threshold (0.075 N) and the compartment immediately preceding it (i.e., the compartment adjacent to the compartment where the number of compartments exceeds 0.075 N on the "side of the low refractive index layer opposite the hard coat layer"). Obtain a line (hereinafter referred to as the "boundary line") by fitting the obtained coordinates with a linear function in the direction in which the "side of the low refractive index layer opposite the hard coat layer" extends. Define the region between this boundary line and the "side of the low refractive index layer on the hard coat layer side" as the "region where hollow silica particles exist". Define the region between this boundary line and the "side of the low refractive index layer opposite the hard coat layer" as the "region where hollow silica particles do not exist". In other words, the boundary line is the boundary between the "region where hollow silica particles exist" and the "region where hollow silica particles do not exist."

[0049] If hollow silica particles are uniformly dispersed in the thickness direction of the low refractive index layer, and are predominantly located on the side opposite the hard coat layer of the low refractive index layer, then a large number of hollow silica particles will be present on the side opposite the hard coat layer of the low refractive index layer. Therefore, if hollow silica particles are uniformly dispersed in the thickness direction of the low refractive index layer, and are predominantly located on the side opposite the hard coat layer of the low refractive index layer, the boundary line obtained by the above procedure will approximately coincide with the side opposite the hard coat layer of the low refractive index layer, making it impossible to identify the region where hollow silica particles do not exist.

[0050] The reason why the threshold for the number of sections corresponding to hollow silica particles was set to 7.5% of the maximum value N when obtaining the coordinates that form the boundary between the "region where hollow silica particles do not exist" and the "region where hollow silica particles exist" will be explained using Figures 5 and 6. Figures 5 and 6 are schematic diagrams showing how hollow silica particles are distributed in the low refractive index layer and the correlation between these schematic diagrams and the positional information (bar graph) obtained by procedure (3). Figure 5(a) is a schematic diagram showing how hollow silica particles are densely arranged in the thickness direction of the low refractive index layer, starting from the hard coat layer side of the low refractive index layer. To simplify the explanation, Figure 5(a) is an example in which hollow silica particles are arranged in two layers in the thickness direction of the low refractive index layer. In Figure 5(a), the upper side is located on the "side opposite the hard coat layer of the low refractive index layer," and the lower side is located on the "side of the hard coat layer of the low refractive index layer." In other words, Figure 5(a) shows an ideal distribution state where the arrangement of hollow silica particles is not disordered on the side of the low refractive index layer opposite the hard coat layer. Figure 5(b) is a bar graph showing the number of compartments in the thickness direction corresponding to the hollow silica particles in the case of the hollow silica particle distribution shown in Figure 5(a). If the arrangement of hollow silica particles is not disordered on the side of the low refractive index layer opposite the hard coat layer as in Figure 5(a), then the boundary line between the "region where hollow silica particles exist" and the "region where hollow silica particles do not exist" can be clearly defined when moving in the thickness direction of the low refractive index layer from the "side of the low refractive index layer opposite the hard coat layer" to the first compartment where the number of compartments exceeds 0, and the compartment immediately preceding it.

[0051] Such disorder in the arrangement can occur due to thermal convection within the coating solution and differences in the settling velocity of hollow silica particles when the low refractive index layer coating solution is applied and dried, as will be described later. Furthermore, disorder in the arrangement can occur during the process of cutting the embedded sample to prepare section samples in order to obtain a vertical cross-sectional image of the anti-reflective member in step 1. Figure 6(a) schematically shows how one hollow silica particle, indicated by shading, protrudes from the other hollow silica particles on the side opposite to the hard coat layer of the low refractive index layer. In Figure 6(a), the upper side is located on the side opposite to the hard coat layer of the low refractive index layer, and the lower side is located on the side facing the hard coat layer of the low refractive index layer. Figure 6(b) is a bar graph showing the number of sections in the thickness direction corresponding to the hollow silica particles in the case of the hollow silica particle distribution shown in Figure 6(a). In such cases, when moving in the thickness direction of the low refractive index layer from the "side opposite the hard coat layer of the low refractive index layer," the first section where the number of sections exceeds zero is due to the hollow silica particles shown in shaded areas. In Figure 6(b), compared to Figure 5(b), the first section where the number of sections exceeds zero is located on the "side opposite the hard coat layer of the low refractive index layer." In the case of Figure 6(b), if we define the boundary between the first section where the number of sections exceeds zero and the section immediately preceding it as the boundary line between the "region where hollow silica particles exist" and the "region where hollow silica particles do not exist" (the line indicated by L1 in Figure 6(b)), then when moving in the thickness direction of the low refractive index layer from the "side opposite the hard coat layer of the low refractive index layer," there are no hollow silica particles other than the shaded hollow silica particles between that section and the section where a large number of other hollow silica particles appear (the line indicated by L2 in Figure 6(b)). In this respect, if we define the line indicated by L1 in Figure 6(b) as the boundary line, we cannot appropriately evaluate whether or not the hollow silica particles are unevenly distributed.

[0052] Therefore, in this disclosure, a value obtained by multiplying the maximum value N by a predetermined value is used as a threshold, and the boundary line between the "region where hollow silica particles exist" and the "region where hollow silica particles do not exist" is obtained from the coordinates between the first section that exceeds the threshold and the section immediately preceding it. By doing so, the boundary line can be appropriately obtained while taking into account the disorder in the arrangement of hollow silica particles as described above. If the threshold is made too small, as explained in Figure 6(b) above, it will be affected by the disorder in the arrangement of hollow silica particles, and it will not be possible to appropriately evaluate whether or not hollow silica particles are unevenly distributed. On the other hand, if the threshold is made too large, the boundary line will be located within the region where many hollow silica particles exist, for example, on the "side of the hard coat layer of the low refractive index layer" side of the line indicated by L2 in Figure 6(b). In other words, the "region where hollow silica particles exist" obtained in step (4) will be estimated to be smaller than reality. Therefore, even if hollow silica particles are uniformly distributed within the low refractive index layer, or if they are unevenly distributed on the side of the low refractive index layer opposite the hard coat layer, it may be incorrectly determined that the hollow silica particles are unevenly distributed on the side of the low refractive index layer opposite the hard coat layer. As a result of our investigation, we have confirmed that by setting the threshold to 7.5% of the maximum value N (0.075 N), the boundary line between the "region where hollow silica particles exist" and the "region where hollow silica particles do not exist" obtained by the procedure of this disclosure generally coincides with the boundary line that can be visually determined from a cross-sectional image (for example, the image taken in step 1 above). Therefore, it can be said that the method of this disclosure can appropriately determine whether or not hollow silica particles are unevenly distributed towards the hard coat layer in the thickness direction of the low refractive index layer.

[0053] -Procedure (5)- In the first image, the ratio of the thickness of the region containing hollow silica particles to the thickness of the low refractive index layer (thickness of the region containing hollow silica particles / thickness of the low refractive index layer, hereinafter simply referred to as the "thickness ratio") is calculated using the following procedure. Let Y1 be the coordinate of the intercept between the left edge of the corrected image obtained in Procedure (1) and the "surface of the low refractive index layer opposite to the hard coat layer". Let Y2 be the coordinate of the boundary between the last section obtained in Procedure (4) where the number of orthogonal sections exceeds 0, and the section adjacent to this section on the hard coat layer side where the number of orthogonal sections becomes 0. Coordinate Y2 corresponds to the coordinate of the intercept between the left edge of the superimposed image and the "surface of the low refractive index layer on the hard coat layer side". Let Y3 be the coordinate of the boundary between the section obtained in Procedure (4) where the number of sections of the region corresponding to hollow silica particles exceeds 7.5% of the maximum value N, and the section immediately preceding it. Coordinate Y3 corresponds to the coordinate of the intercept between the left edge of the superimposed image and the boundary line between the "region where hollow silica particles exist" and the "region where hollow silica particles do not exist." Y2-Y1 corresponds to the thickness of the low refractive index layer. Y2-Y3 corresponds to the thickness of the "region where hollow silica particles exist." Therefore, in this disclosure, the thickness ratio is calculated from the following formula: Thickness ratio = (Y2-Y3) / (Y2-Y1)

[0054] -Step 3- The same process as in Steps 1 and 2 is performed on the 2nd to 10th images. The 1st to 10th images are images taken from cut samples taken from different parts of the anti-reflective material. The average value is calculated using the thickness ratios of the 8 images obtained by excluding the maximum and minimum values ​​from the thickness ratios calculated for the 10 images. As described above, the boundary line obtained by setting the threshold of the number of compartments corresponding to the hollow silica particles to 7.5% of the maximum value N generally coincides with the boundary line determined by visual inspection. For this reason, the thickness of the "area where hollow silica particles exist" can be considered as the thickness of the "area where hollow silica particles are unevenly distributed". Accordingly, the average value of the thickness ratios of the above 8 images can be considered as the "ratio of the thickness of the area where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer". The ratio of the thickness of the area where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer (thickness of the area where hollow silica particles are unevenly distributed / thickness of the low refractive index layer) is an indicator that the hollow silica particles of the low refractive index layer of the anti-reflective material are unevenly distributed on the interface side between the hard coat layer and the low refractive index layer. If the ratio of the thickness of the region where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer is 0.90 or less, it is determined that the hollow silica particles are unevenly distributed towards the hard coat layer in the thickness direction of the low refractive index layer.

[0055] In this disclosure, by setting the ratio to 0.90 or less, a region without hollow silica particles is sufficiently formed on the surface side of the low refractive index layer (opposite the hard coat layer of the low refractive index layer), making it easier to improve the scratch resistance of the anti-reflective member. In terms of improving scratch resistance, the ratio is preferably 0.87 or less, and more preferably 0.85 or less. Furthermore, the ratio is preferably 0.50 or more, more preferably 0.60 or more, and even more preferably 0.70 or more. By setting the ratio to 0.50 or more, it is easier to lower the refractive index of the low refractive index layer and improve anti-reflective properties. The thickness of the low refractive index layer is sufficiently smaller than the wavelength of visible light. Therefore, the refractive index of the low refractive index layer is the refractive index of the components constituting the low refractive index layer as an average. Accordingly, by increasing the ratio, it is easier to lower the refractive index of the low refractive index layer. That is, in this disclosure, the ratio of the thickness of the region where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer is preferably 0.50 or more and 0.90 or less.

[0056] The average particle diameter r of the hollow silica particles is preferably 40 nm or more, more preferably 45 nm or more, and even more preferably 50 nm or more, in order to facilitate lowering the refractive index of the low refractive index layer. The average particle diameter r of the hollow silica particles is preferably 100 nm or less, more preferably 85 nm or less, and even more preferably 75 nm or less, in order to facilitate good scratch resistance. The average particle diameter r of the hollow silica particles is calculated from an image of the vertical cross-section of the anti-reflective material taken with a scanning transmission electron microscope. The average particle diameter of the hollow silica particles contained in the low refractive index layer is calculated by the following steps F1 to F3. F1: The cross-section of the section sample is imaged with a scanning transmission electron microscope (STEM) using the method described above. The acceleration voltage of the scanning transmission electron microscope is adjusted to 30 kV, and the magnification is adjusted to a range of 100,000x to 300,000x. F2: Ten arbitrary hollow silica particles contained in the low refractive index layer are extracted from the observed image, and the particle diameter of each hollow silica particle is calculated. Furthermore, in the observation image, particles in which a cavity is observed inside the contour can be extracted as hollow silica particles. The particle diameter of each hollow silica particle is defined as the distance between two arbitrary parallel lines that maximizes the distance between the two lines when the cross-section of the hollow silica particle is sandwiched between them. F3: Perform the same procedure five times on observation images of the same sample on a different screen, and the value obtained from the numerical average of the particle diameters of a total of 50 particles is taken as the average particle diameter of the hollow silica particles contained in the low refractive index layer.

[0057] The porosity of the hollow silica particles is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more, from the viewpoint of lowering the refractive index, and preferably 85% or less, more preferably 80% or less, and even more preferably 75% or less, from the viewpoint of strength.

[0058] The higher the proportion of hollow silica particles, the lower the refractive index of the low refractive index layer. On the other hand, if the proportion of hollow silica particles is too high, the scratch resistance tends to decrease. For this reason, the proportion of hollow silica particles is preferably 70 parts by mass or more and 250 parts by mass or less, more preferably 100 parts by mass or more and 200 parts by mass or less, and even more preferably 130 parts by mass or more and 170 parts by mass or less, per 100 parts by mass of the binder component.

[0059] It is preferable that the hollow silica particles are stacked in the thickness direction of the low refractive index layer. In Figure 1, most of the hollow silica particles 32 are stacked in the thickness direction of the low refractive index layer 30.

[0060] As a means of causing the hollow silica particles to be unevenly distributed towards the hard coat layer in the thickness direction of the low refractive index layer, the means described in B1 below can be mentioned. Furthermore, according to the means described in B1 below, the first solid particles can be positioned in the region where the hollow silica particles are unevenly distributed in the thickness direction of the low refractive index layer. More preferably, the means described in B1 below and the means described in B2 and / or B3 below can be implemented. B1: Connect the hollow silica particles and solid particles via a silane coupling agent. When the hollow silica particles and solid particles are connected, the hollow silica particles also settle towards the hard coat layer as the solid particles, which have a higher specific gravity, settle towards the hard coat layer, thus allowing the hollow silica particles to be unevenly distributed towards the hard coat layer. Also, since the specific gravity of the solid particles is heavier than that of the hollow silica particles, the first solid particles can be positioned in the region where the hollow silica particles are unevenly distributed. B2: Shorten the drying time of the coating liquid for the low refractive index layer. By shortening the drying time of the coating solution for the low refractive index layer, it is easier to suppress the floating of hollow silica particles, which have a low specific gravity, to the surface side of the low refractive index layer. B3: Lower the affinity between hollow silica particles and the solvent compared to the affinity between solid particles and the solvent. By doing so, it is easier to suppress the floating of hollow silica particles to the surface side of the low refractive index layer as the solvent dries.

[0061] In the method B1 described above, it is preferable to carry out the methods B1-1 and B1-2 below in order to facilitate the linking of hollow silica particles and solid particles via the silane coupling agent. B1-1: Add a hydrolysis catalyst such as an acid or alkali to the silane coupling agent. This process yields a liquid containing the silane coupling agent from which the alkoxysilyl groups have been pre-hydrolyzed. B1-2: Add the liquid obtained in B1-1 to a dispersion of hollow silica particles and solid particles to react the silane coupling agent with the hollow silica particles and solid particles.

[0062] A common surface treatment method for hollow silica particles and solid particles involves adding a silane coupling agent to a dispersion containing the hollow silica particles and solid particles, and, if necessary, adding an acid or alkali as a hydrolysis catalyst. In the aforementioned common method, hydrolysis converts the alkoxysilyl groups (Si-OR) of the silane coupling agent to highly reactive silanol groups (Si-OH). However, because the concentration of silanol groups in the reaction system is low, it is difficult to link the hollow silica particles and solid particles via the silane coupling agent. On the other hand, as in the methods B1-1 and B1-2 above, by hydrolyzing the alkoxysilyl groups of the silane coupling agent beforehand, the concentration of silanol groups in the reaction system increases, making it easier to link the hollow silica particles and solid particles via the silane coupling agent. When implementing the methods B1-1 and B1-2 above, it is preferable that the spacer portion connecting the organic functional group and the alkoxysilyl group in the silane coupling agent is a long-chain hydrocarbon chain. By using a long-chain hydrocarbon chain as the spacer, the hydrophobicity of the silane coupling agent is improved, which enhances the dispersion stability of the linked particles and thus improves the overall stability of the composition.

[0063] Furthermore, as a means of unevenly distributing the hollow silica particles towards the hard coat layer in the thickness direction of the low refractive index layer, a means of creating a two-layer structure for the low refractive index layer can also be mentioned. Specifically, this means of forming a first low refractive index layer using a first low refractive index layer coating solution containing a binder component, hollow silica particles, and first solid particles, and then forming a second low refractive index layer using a second low refractive index layer coating solution containing a binder component but not containing hollow silica particles or the first solid particles. The binder component of the first low refractive index layer and the binder component of the second low refractive index layer may be the same component or may be different components.

[0064] 《First Solid Particles》 The low refractive index layer must contain first solid particles. When the surface of the low refractive index layer is rubbed, if the hollow silica particles are destroyed or the binder resin portion is abraded, it may lead to scratches that are visible to the naked eye and impair the quality of the display. Also, if the binder resin portion is abraded, the film thickness of the low refractive index layer changes, which may cause a change in color. By including first solid particles in the low refractive index layer, the destruction of the hollow silica particles is suppressed, and the abrasion of the binder resin portion of the low refractive index layer is suppressed, thereby improving the scratch resistance of the low refractive index layer. As a result, the occurrence of scratches due to rubbing and changes in color can be suppressed. When the average particle diameter of the hollow silica particles is defined as r and the average particle diameter of the first solid particles is defined as R1, the first solid particles must satisfy the relationship r < R1. By using solid particles that satisfy the relationship r < R1, the stress on the hollow silica particles when the surface of the low refractive index layer is rubbed can be reduced, and the fracture of the hollow silica particles can be suppressed. In addition, the binder resin portion becomes less prone to abrasion. As a result, the scratch resistance of the anti-reflective material can be improved, and scratches and changes in color can be suppressed.

[0065] By increasing R1 / r, the stress on the hollow silica particles can be reduced, thereby improving the scratch resistance of the anti-reflective material. On the other hand, if R1 / r is too large, the first solid particles may easily detach from the low refractive index layer, which may reduce scratch resistance. Also, if R1 / r is too large, the average particle size of the hollow silica particles may become too small, which may increase the reflectance. For this reason, R1 / r is preferably greater than 1.0 and less than or equal to 2.0, more preferably between 1.1 and 1.8, and even more preferably between 1.2 and 1.6.

[0066] The average particle diameter R1 of the first solid particles is preferably 50 nm or more, more preferably 60 nm or more, and even more preferably 70 nm or more, in order to improve scratch resistance. The average particle diameter R1 of the first solid particles is preferably 150 nm or less, more preferably 120 nm or less, and even more preferably 100 nm or less, in order to suppress the first solid particles from easily falling out of the low refractive index layer. The average particle diameter R1 of the first solid particles is calculated from an image of the vertical cross-section of the anti-reflective member obtained by scanning transmission electron microscopy. The average particle diameter of the first solid particles is calculated by the following steps G1 to G3. G1: The cross-section of the section sample is imaged with a scanning transmission electron microscope (STEM) using the method described above. The acceleration voltage of the scanning transmission electron microscope is adjusted to 30 kV, and the magnification is adjusted to a range of 100,000x to 300,000x. G2: Ten arbitrary first solid particles contained in the low refractive index layer are extracted from the observed image, and the particle diameter of each first solid particle is calculated. Furthermore, in the observation image, particles that do not show a cavity inside the contour and are larger than hollow silica particles are extracted as the first solid particles. The particle diameter of each first solid particle is defined as the distance between two arbitrary parallel lines that maximizes the distance between the two lines when the cross-section of the first solid particle is sandwiched between them. G3: The same procedure is performed five times on observation images of the same sample on different screens, and the value obtained from the number average of the particle diameters of a total of 50 particles is defined as the average particle diameter of the first solid particles contained in the low refractive index layer.

[0067] In the thickness direction of the low refractive index layer, it is more preferable that the first solid particle is located in a region where hollow silica particles are unevenly distributed. In Figure 1, in the thickness direction of the low refractive index layer 30, the first solid particle 33 is located in region S where hollow silica particles are unevenly distributed. By positioning the first solid particle in a region where hollow silica particles are unevenly distributed, the shedding of the first solid particle can be suppressed, making it easier to improve scratch resistance. By stacking the hollow silica particles in the thickness direction of the low refractive index layer, it is easier to position the first solid particle in a region where hollow silica particles are unevenly distributed. Furthermore, when the first solid particle is located in a region where hollow silica particles are unevenly distributed, the outermost surface of the low refractive index layer tends to become smoother. Therefore, a good anti-reflective effect can be obtained.

[0068] In this specification, "the first solid particle is located in a region where hollow silica particles are unevenly distributed" means that the centers of 90% or more of the first solid particles are located in a region where hollow silica particles are unevenly distributed. Whether or not the first solid particle is located in a region where hollow silica particles are unevenly distributed is determined by the following steps (i) to (vii). Image analysis software is used for the determination. The determination also uses the following images and coordinate information obtained in the step of determining whether or not hollow silica particles are unevenly distributed towards the hard coat layer in the thickness direction of the low refractive index layer. - Corrected image (obtained in step (1) of step 2) - Coordinate Y1 (obtained in step (1) of step 2) - Coordinate Y2 (obtained in step (4) of step 2) - Coordinate Y3 (obtained in step (4) of step 2) <Determination procedure> (i) Obtain an image (extracted image) from the corrected image in which the entire low refractive index layer, the side of the low refractive index layer opposite the hard coat layer, and the side of the low refractive index layer facing the hard coat layer can be clearly identified. (ii) The extracted image is binarized using adaptive thresholding to obtain binarized image A. (iii) Distance transformation is performed on binarized image A obtained in step (ii) above to obtain a two-dimensional distance map. (iv) Watershed processing is performed on the distance map to identify the contour lines of valleys in the image. A label image is obtained in which pixels within the region enclosed by the contour lines of each valley are assigned labels of 1 or more, and the remaining regions are assigned labels of 0. (v) The number of pixels in the regions in the label image that are assigned labels of 1 or more is measured. The label image is converted to binarized image B. Starting with regions with a label of 1, moments are calculated for regions where the number of pixels is greater than or equal to the threshold, and the coordinates of the centroid of each region are obtained. The number of regions (N0) for which moment calculations have been performed is obtained. (vi) Based on the coordinates of each region obtained in step (v), the centroid of each region is displayed on the label image. Then, the number of regions (N1) in which the centroid is located in a region where hollow silica particles exist is obtained. Next, calculate the ratio of quantity N1 to quantity N0. (vii) Perform the same steps as in (i) to (vi) for the second to tenth images. Calculate the average value using the eight quantities obtained by excluding the maximum and minimum values ​​from the calculated quantity ratios for the ten images.If the calculated average value is 90% or higher, it is determined that "in the thickness direction of the low refractive index layer, the first solid particle is located in a region where hollow silica particles are unevenly distributed."

[0069] The following describes more detailed embodiments of the above procedures (i) to (vii). -Procedure (i)- The corrected image obtained from the first image by procedure (1) of step 2 described above is imported into image analysis software. From the corrected image, an image is extracted in which the entire low refractive index layer, the surface of the low refractive index layer opposite the hard coat layer, and the surface of the low refractive index layer on the hard coat layer side can be clearly identified. Specifically, a coordinate (let's call it coordinate Y4) is obtained at a predetermined pixel distance from coordinate Y1 on the side opposite the low refractive index layer. A line (LF1) fitted to the corrected image using a linear function in the direction in which the "surface of the low refractive index layer opposite the hard coat layer" extends from coordinate Y4 is displayed. Also, a coordinate (let's call it coordinate Y5) is obtained at a predetermined pixel distance from coordinate Y2 on the hard coat layer side of the corrected image. A line (LF2) fitted to the direction in which the "surface of the low refractive index layer opposite the hard coat layer" extends from coordinate Y5 is displayed. An image is obtained by extracting the space between line LF1 and line LF2 from the corrected image. The "predetermined pixels" are set appropriately within a range where the surface of the low refractive index layer opposite the hard coat layer and the surface of the low refractive index layer facing the hard coat layer can be clearly identified. For example, they are set within a range of 20 to 30 pixels. Hereinafter, the extracted image will be referred to as the "extracted image". Coordinate Y1 is the coordinate of the intercept between the left edge of the corrected image and the "surface of the low refractive index layer opposite the hard coat layer". Coordinate Y2 is the coordinate of the intercept between the left edge of the superimposed image and the "surface of the low refractive index layer facing the hard coat layer". As explained in steps (2) to (4) above, the superimposed image is obtained from the corrected image, so coordinate Y2 can be said to correspond to the coordinate of the intercept between the left edge of the corrected image and the "surface of the low refractive index layer facing the hard coat layer". Therefore, the low refractive index layer is located between lines LF1 and LF2 in the corrected image. The extracted image includes the entire low refractive index layer, the area corresponding to the space of the sample chamber of the scanning transmission electron microscope, and a part of the layer located below the low refractive index layer. By using the extracted images in the analysis described later, the influence of particles contained in layers other than the low refractive index layer (for example, particles in the hard coat layer) on the analysis can be almost completely eliminated.

[0070] -Procedure (ii)- Import the extracted image into image analysis software and perform binarization using adaptive thresholding. The resulting binarized image is referred to as "Binarized Image A". In Binarized Image A obtained by Procedure (ii), the first solid particles contained in the low refractive index layer are generally extracted. However, in Binarized Image A, in addition to solid particles displayed individually, there may be cases where only a portion of the first solid particles are displayed overlapping with other particles, second solid particles with a smaller particle size than the first solid particles, and the outlines of some hollow silica particles are extracted. If Binarized Image A containing these may be used, the accuracy of determining the center position of the first solid particles may decrease. For this reason, Procedure (iii) is performed.

[0071] -Procedure (iii)- Import the binarized image A into image analysis software and perform distance transformation. In distance transformation, the distance from each pixel of binarized image A to the pixel with a pixel value of 0 is calculated. Based on the obtained distances, a distance map is created. Normally, distance maps are three-dimensional, but here they are converted into a two-dimensional heatmap distance map. The pixel values ​​in the two-dimensional distance map correspond to the distances. In the distance map, the distance to the pixel with a pixel value of 0 is represented by changes in color intensity or hue, etc. Note that a pixel here is considered to be one pixel unit. In the binarized image A above, solid particles are shown as white circles, and hollow silica particles are shown with white outlines and black internal cavities. In the distance map, solid particles are displayed so that the distance increases towards the center, while the distance to the outline of hollow silica particles is smaller than that of solid particles. Also, in this disclosure, since the average particle diameter of the first solid particle is larger than that of the second solid particle, the distance at the center of the particle is greater for the first solid particle than for the second solid particle. Therefore, by creating a distance map, the differences between the first solid particle, the hollow silica particle, and the second solid particle can be highlighted.

[0072] -Procedure (iv)- Watershed processing is performed on the distance map. Watershed processing is a process that treats the gradient of the pixel values ​​of an image as a topographic map with valleys, and assumes that water flows from the bottom of the valley within this topographic map, and determines the watershed (wall) that collects the water as an outline. This process makes it possible to separate overlapping objects in the image. In this disclosure, in the above-mentioned cropped image, particles may be displayed overlapping each other. By applying Watershed processing, overlapping particles can be separated. Specifically, in the distance map, pixels where the pixel value locally reaches a maximum value are detected. The local area for searching for the maximum value is set to a 5x5 pixel square. Markers are assigned to the detected pixels as peaks. Watershed processing is performed on the distance map with markers assigned to the peaks. First, the pixel values ​​of the distance map are multiplied by -1. This process transforms the distance map so that the peaks become valleys. Next, the binarized image A obtained in step (ii) is used as a mask to exclude areas that do not correspond to particles. Then, in the transformed distance map, the process of filling each valley with water from the bottom is simulated to identify the valley contours. The area enclosed by each valley contour corresponds to the area occupied by individual particles in the distance map. Areas outside the valley contours correspond to areas where no particles exist (i.e., the background). A label of an integer value of 1 or greater is assigned to each pixel within the area enclosed by each valley contour. A label of 0 is assigned to pixels outside the area enclosed by the valley contours. This image is called the "labeled image". Figure 7 shows an example of a labeled image. Figure 7 is a labeled image obtained from a cropped image containing three particles. Note that actual labeled images are obtained from cropped images containing many more particles than those in Figure 7. Figure 7 contains three areas enclosed by valley contours. These areas are shown in white. Each pixel within the region enclosed by the valley's outline is assigned a label ranging from 1 to 3. That is, a region enclosed by a single valley's outline consists of pixels assigned the same integer. Pixels corresponding to areas without particles (background) are displayed in black, and each pixel is assigned the label 0.

[0073] - Step (v) - For the regions in the label image to which one or more labels are assigned, measure the number of pixels in each region. The number of pixels corresponds to the area of each particle. In FIG. 7, the number of pixels to which label 1 is assigned is 9 pixels, the number of pixels to which label 2 is assigned is 18 pixels, and the number of pixels to which label 3 is assigned is 7 pixels. These values correspond to the areas of the individual particles. Next, convert the label image into a binary image with the regions to which one or more integer-valued labels are assigned having a pixel value of 1 and the regions to which a label of 0 is assigned having a pixel value of 0. This image is referred to as the "binary image B". The regions with a pixel value of 1 correspond to the individual particles (first solid particles). Next, in order from the region with label 1, compare the number of pixels in the region with the threshold value. For the regions where the number of pixels is greater than or equal to the threshold value, calculate the moment (statistical feature quantity of the image) of each region in the binary image B and obtain the coordinates of the center of gravity of each region. For the regions where the number of pixels is less than the threshold value, do not perform moment calculation. Repeat this operation for the total number of assigned labels. The pixel number threshold value is set by referring to the numerical range of the average particle diameters of the first solid particles, hollow silica particles, and second solid particles described in the text of the specification. Also, obtain the number (N0) of regions for which moment calculation has been performed.

[0074] Since the number of pixels in the region corresponds to the area of each particle, only the coordinates of the center of gravity of the first solid particles can be obtained by the above operations. The number N0 corresponds to the number of first solid particles included in the label image (binary image B). In the binary image B, for the region D occupied by the particle (region) i, if the pixel value at (x ｉ , y ｉ ) ∈ D ｉ is set as I(x ｉ , y ｉ ), the moment M ｉ of the (m + n)th order is a feature quantity obtained by the following formula. ｎｍ At this time, the zeroth-order moment M ００ is represented by the following formula. In the binary image B, M ００ is the region D occupied by the particle (region) i ｉIt corresponds to the area of ​​[the specified area]. First moment M １０ M ０１ It can be expressed by the following formula. The centroid coordinates (x) of particle (region) i ｉ , y ｉ ) is calculated using the following formula.

[0075] -Procedure (vi)- Based on the labels, the coordinates of each region obtained in procedure (v) are linked to the regions on the label image. Next, the centroid of each region is displayed on the label image. Since the binarized image B is obtained from the label image, the coordinates of the centroid of each region in the binarized image B are the same as the coordinates of the centroid of each region in the label image. Furthermore, a line (LF3) fitted to the label image using a linear function in the direction in which the surface opposite the hard coat layer of the low refractive index layer extends from coordinate Y2 is displayed. Line LF3 corresponds to the surface on the hard coat layer side of the low refractive index layer. Also, a line (LF4) fitted to the label image using a linear function in the direction in which the surface opposite the hard coat layer of the low refractive index layer extends from coordinate Y3 is displayed. Line LF4 corresponds to the boundary between the region where hollow silica particles do not exist and the region where hollow silica particles exist. The area between line LF3 and line LF4 is a region where hollow silica exists in the low refractive index layer, and corresponds to the "region where hollow silica is unevenly distributed in the low refractive index layer." Next, the number of regions (N1) in which the centroid is located between line LF3 and line LF4 is measured in the label image. The number N1 corresponds to the number of first solid particles whose centers are located in the region where hollow silica particles exist. The ratio of number N1 to number N0 (N1 / N0 × 100, hereinafter referred to as the "number ratio") is calculated. The calculated number ratio corresponds to the number ratio of first solid particles whose centers are located in the region where hollow silica particles exist in the first image.

[0076] -Procedure (vii)- Perform the same steps as in procedures (i) to (vi) for the second to tenth images. Calculate the average value using the eight values ​​obtained by excluding the maximum and minimum values ​​from the calculated percentage of particles for the ten images. If the calculated average value is 90% or higher, it is determined that "in the thickness direction of the low refractive index layer, the first solid particle is located in the region where hollow silica particles are unevenly distributed."

[0077] In this disclosure, in order to maintain sufficient scratch resistance, the number ratio is preferably 95% or more, and more preferably 100%.

[0078] As described above, in this specification, "the first solid particles are located in the region where hollow silica particles are unevenly distributed" means that the centers of 90% or more of the first solid particles are located in the region where hollow silica particles are unevenly distributed. In this case, it is even more preferable that, when the low refractive index layer is viewed in cross-section, the total area of ​​the region where hollow silica particles are unevenly distributed is 3 / 4 or more of the total cross-sectional area of ​​the first solid particles. "The total area of ​​the region where hollow silica particles are unevenly distributed is 3 / 4 or more of the total cross-sectional area of ​​the first solid particles" means that there are few first solid particles protruding from the region where hollow silica particles are unevenly distributed toward the side opposite the hard coat layer of the low refractive index layer, and that the majority are located in the region where hollow silica particles are unevenly distributed. As a result, scratch resistance is improved.

[0079] Whether the area of ​​the region where hollow silica particles are unevenly distributed is 3 / 4 or more of the cross-sectional area of ​​the first solid particle is determined by the following procedure (a) to (d). The determination uses the label image obtained up to procedure (v) in the determination of whether the first solid particle is located in the region where hollow silica particles are unevenly distributed. <Determination procedure> (a) Measure the number of pixels in the region to which one or more labels are assigned in the label image obtained in procedure (v) and calculate the sum (S0). (b) Obtain an image cut out from the label image obtained in procedure (v) showing the region where hollow silica is unevenly distributed in the low refractive index layer. (c) Measure the number of pixels in the region to which one or more labels are assigned in the cut-out image and calculate the sum (S1). Also calculate the rate of change of the sum ((S1 - S0) / S0 × 100). (d) Perform the same work as in procedure (a) to (c) for the second to tenth images. The average value is calculated using the 8 values ​​obtained by excluding the maximum and minimum values ​​from the percentage change in the total area calculated for the 10 images. If the calculated average value is -25% or greater, it is determined that "in the thickness direction of the low refractive index layer, the first solid particle is located in a region where hollow silica particles are unevenly distributed."

[0080] The following describes more detailed embodiments of the above procedures (a) to (d). -Procedure (a)- In the label image obtained in procedure (v), the number of pixels in each region to which one or more labels are assigned is measured. The sum of the measured number of pixels (S0) is calculated. This sum (S0) corresponds to the sum of the areas of the first solid particles displayed in the cropped image.

[0081] -Procedure (b)- In the label image obtained in procedure (v), a line (LF3) fitted with a linear function from coordinate Y2 in the direction in which the "surface opposite the hard coat layer of the low refractive index layer" extends is displayed. Also, in the distance image map, a line (LF4) fitted with a linear function from coordinate Y3 in the direction in which the "surface opposite the hard coat layer of the low refractive index layer" extends is displayed. An image is obtained by cutting out the area between line LF3 and line LF4 from the label image. The area between line LF3 and line LF4 corresponds to the region where hollow silica is unevenly distributed in the low refractive index layer. Therefore, only the "region where hollow silica is unevenly distributed" is displayed in the cut-out image.

[0082] - Procedure (c) - In the image extracted in Procedure (b) showing the "region where hollow silica is unevenly distributed," measure the number of pixels within the region to which one or more labels are assigned. Calculate the sum of the measured pixels (S1). Calculate the rate of change of the sum of pixels using the following formula: Rate of change of sum = (S1 - S0) / S0 × 100

[0083] -Procedure (d)- Perform the same procedure as in procedures (a) to (c) for the second to tenth images. Calculate the average value using the eight values ​​obtained by excluding the maximum and minimum values ​​from the percentage change of the total sum calculated for the ten images. If the calculated average value is -25% or more, it is determined that "the sum of the areas within the region where hollow silica particles are unevenly distributed is 3 / 4 or more of the sum of the cross-sectional areas of the first solid particles." If many of the first solid particles protrude from the "region where hollow silica is unevenly distributed" toward the side opposite the low refractive index hard coat layer, the protruding parts will be cut off in the image obtained in procedure (b). Therefore, the sum of the areas of the first solid particles S1 obtained in procedure (c) will be significantly less than the sum of the areas of the first solid particles S0 obtained in procedure (a). Also, for all first solid particles, if the entirety of the first solid particle is located within the region where hollow silica particles are unevenly distributed, S1 and S0 will be equal. In other words, the smaller the absolute value of the rate of change of the sum (the larger the rate of change of the sum), the fewer first solid particles protrude from the region where hollow silica particles are concentrated toward the side opposite the hard coat layer of the low refractive index layer, and the more likely it is that the majority of these particles reside in the region where hollow silica particles are concentrated.

[0084] In this disclosure, in order to maintain sufficient scratch resistance, the rate of change of the total area is preferably -20% or more, more preferably -15% or more, and even more preferably -10% or more.

[0085] Examples of the first solid particles include solid silica particles, solid alumina particles, solid titania particles, and solid zirconia particles. Among these, solid silica particles and solid alumina particles are preferred because they offer an excellent balance between scratch resistance and low refractive index. Solid alumina particles are preferred because they easily provide good pencil hardness. The first solid particles may contain two types. When the first solid particles contain two types of particles, it is preferable that one is a solid alumina particle and the other is a solid silica particle.

[0086] The higher the content of the first solid particles, the easier it is to improve scratch resistance. On the other hand, if the content of the first solid particles is too high, the refractive index of the low refractive index layer tends to increase. For this reason, the content of the first solid particles is preferably 5 parts by mass or more and 50 parts by mass or less, more preferably 10 parts by mass or more and 45 parts by mass or less, and even more preferably 20 parts by mass or more and 40 parts by mass or less, per 100 parts by mass of the binder component.

[0087] The ratio of the content of hollow silica particles to the content of first solid particles (content of hollow silica particles / content of first solid particles) is preferably 3.0 or more and 20.0 or less, more preferably 4.0 or more and 10.0 or less, and even more preferably 5.0 or more and 7.5 or less. By setting the ratio within the above range, it is possible to easily improve scratch resistance and maintain good anti-reflective properties.

[0088] 《Second Solid Particles》 The low refractive index layer may further contain second solid particles. When the average particle diameter of the second solid particles is defined as R2, particles that satisfy the relationship R2 < r < R1 correspond to the second solid particles in this specification. By including the second solid particles, it is possible to further improve scratch resistance.

[0089] The average particle diameter R2 of the second solid particles is preferably 5 nm or more, more preferably 7 nm or more, and even more preferably 9 nm or more. The average particle diameter R2 of the second solid particles is preferably 50 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less. The average particle diameter R2 of the second solid particles is calculated from an image of the vertical cross-section of the anti-reflective material taken with a scanning transmission electron microscope. The average particle diameter of the second solid particles is calculated by the following steps H1 to H3. H1: The cross-section of the section sample is imaged with a scanning transmission electron microscope (STEM) using the method described above. The acceleration voltage of the scanning transmission electron microscope is adjusted to 30 kV, and the magnification is adjusted to a range of 100,000x to 300,000x. H2: Ten arbitrary second solid particles contained in the low refractive index layer are extracted from the observed image, and the particle diameter of each first solid particle is calculated. In the observed image, particles that do not show a cavity inside the contour and are smaller than hollow silica particles are extracted as second solid particles. The particle diameter of each second solid particle is defined as the distance at which the distance between two arbitrary parallel lines is maximized when the cross-section of the second solid particle is sandwiched between them. H3: Perform the same procedure five times on observation images of the same sample on different screens, and the value obtained from the number average of the particle diameters of a total of 50 particles is defined as the average particle diameter of the second solid particles contained in the low refractive index layer.

[0090] Examples of the second solid particles include solid silica particles, solid alumina particles, solid titania particles, and solid zirconia particles. Among these, solid silica particles and solid alumina particles are preferred because they offer an excellent balance between scratch resistance and low refractive index. Solid alumina particles are preferred because they easily provide good pencil hardness. The second solid particles may consist of two types. When the second solid particles consist of two types, it is preferable that one is a solid alumina particle and the other is a solid silica particle.

[0091] In the thickness direction of the low refractive index layer, it is preferable that the second solid particle is located in a region where hollow silica particles are unevenly distributed. In Figure 1, in the thickness direction of the low refractive index layer 30, the second solid particle 34 is located in region S where hollow silica particles are unevenly distributed. By positioning the second solid particle in a region where hollow silica particles are unevenly distributed, the detachment of the second solid particle can be suppressed, making it easier to improve scratch resistance. By stacking the hollow silica particles in the thickness direction of the low refractive index layer, it is easier to position the second solid particle in a region where hollow silica particles are unevenly distributed.

[0092] In this specification, "in the thickness direction of the low refractive index layer, the second solid particles are located in the region where hollow silica particles are unevenly distributed" means that 90% or more of the second solid particles, based on number, are located in the region where hollow silica particles are unevenly distributed. The said percentage is preferably 95% or more, and more preferably 100%. Whether or not the second solid particles are located in the region where hollow silica particles are unevenly distributed, that is, the percentage of the second solid particles located in the region where hollow silica particles are unevenly distributed, based on number, can be determined by the following procedure. First, the "region where hollow silica particles exist" identified in steps 1 to 3 above is superimposed on the first image. For example, two lines that determine the thickness of the "region where hollow silica particles exist," or a frame surrounding the "region where hollow silica particles exist," is superimposed on the first image. The second solid particles that exist between the two lines, or the second solid particles that exist within the frame, can be considered as second solid particles that exist in the "region where hollow silica particles exist." In the first image, the second solid particles and hollow silica particles are visually distinguishable. The number of second solid particles that can be observed in the first image and the number of second solid particles that exist in the region where hollow silica particles exist are counted, respectively. The number of second solid particles that exist in the region where hollow silica particles exist is divided by the total number of second solid particles that can be observed in the first image to calculate the ratio based on the number of particles.

[0093] The higher the content of the second solid particles, the easier it is to improve scratch resistance. On the other hand, if the content of the second solid particles is too high, it becomes difficult to increase the content of hollow silica particles and the first solid particles. For this reason, the content of the second solid particles is preferably 5 parts by mass or more and 30 parts by mass or less, more preferably 7.5 parts by mass or more and 25 parts by mass or less, and even more preferably 10 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of the binder component.

[0094] When the average thickness of the low refractive index layer is defined as d, it is preferable that r < R1 < d. Satisfying the relationship r < R1 < d makes it easier to improve the scratch resistance of the anti-reflective material. d / R1 is preferably 1.01 or more and 1.8 or less, more preferably 1.05 or more and 1.60 or less, and even more preferably 1.10 or more and 1.40 or less.

[0095] The average thickness d of the low refractive index layer is preferably 60 nm or more at the lower limit, more preferably 75 nm or more, and more preferably 90 nm or more. The upper limit is preferably 180 nm or less, more preferably 155 nm or less, and more preferably 130 nm or less.

[0096] 《Binder Component》 The binder component is a component that enables the low refractive index layer to be formed as a layer, and also serves as a binder that holds inorganic particles such as hollow silica particles and first solid particles. The low refractive index layer preferably contains a cured product of a curable resin composition as the binder component. The curable resin composition is a composition containing a curable compound such as a thermosetting resin or an ionizing radiation curable compound. The ratio of the cured product of the curable resin composition to the total binder component of the low refractive index layer is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 90% by mass or more, and most preferably 100% by mass. Examples of curable resin compositions for the low refractive index layer include thermosetting resin compositions and ionizing radiation curable resin compositions, with ionizing radiation curable resin compositions being preferred. That is, the low refractive index layer preferably contains a cured product of an ionizing radiation curable resin composition as the binder component.

[0097] A thermosetting resin composition is a composition containing at least a thermosetting resin, which 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 curable resins as needed in the thermosetting resin composition.

[0098] Ionizing radiation-curable resin compositions are compositions containing compounds having ionizing radiation-curable functional groups (hereinafter also referred to as "ionizing radiation-curable compounds"). Ionizing radiation refers to electromagnetic waves or charged particle beams that have energy quanta capable of polymerizing or crosslinking molecules. Typically, ultraviolet (UV) or electron beams (EB) are used, but other electromagnetic waves such as X-rays and gamma rays, and charged particle beams such as alpha rays and ion beams can also be used. Examples of ionizing radiation-curable functional groups include ethylenically unsaturated bonding groups such as (meth)acryloyl groups, vinyl groups, and aryl groups, as well as epoxy groups and oxetanyl groups. It is preferable that ionizing radiation-curable compounds have two or more ionizing radiation-curable functional groups. As ionizing radiation-curable compounds, compounds having ethylenically unsaturated bonding groups are preferred. Among these, (meth)acrylate compounds having (meth)acryloyl groups are more preferred. Both monomers and oligomers can be used as (meth)acrylate compounds. The (meth)acrylate compound is preferably a polyfunctional (meth)acrylate compound. In this specification, a polyfunctional (meth)acrylate compound means a compound having two or more (meth)acryloyl groups. In this specification, the "polysilsesquioxane with one or more reactive groups substituted" described later is distinguished from the "(meth)acrylate compound". That is, in this specification, the "(meth)acrylate compound" is a concept that does not include "polysilsesquioxane with one or more reactive groups substituted".

[0099] The ionizing radiation-curable compound preferably contains a polyfunctional (meth)acrylate compound. In other words, the low refractive index layer preferably contains a cured product of a polyfunctional (meth)acrylate compound as a binder component.

[0100] The polyfunctional (meth)acrylate compound may be either a monomer or an oligomer, but it is preferable that it contains a monomer. This is because monomers make it easier to uniformly arrange particles such as the first solid particle compared to oligomers. Examples of polyfunctional (meth)acrylate monomers include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate.

[0101] Ionizing radiation-curable compounds can be used individually or in combination of two or more.

[0102] When the ionizing radiation-curable compound is an ultraviolet-curable compound, the coating solution for the low refractive index layer preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator. Examples of photopolymerization initiators include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler ketone, benzoin, benzyldimethyl ketal, benzoyl benzoate, α-acyloxime ester, α-aminoalkylphenone, thioxanthone, etc. The photopolymerization accelerator is one that can reduce polymerization inhibition by air during curing and accelerate the curing rate, and examples include one or more selected from p-dimethylaminobenzoate isoamyl ester, p-dimethylaminobenzoate ethyl ester, etc.

[0103] Polysilsesquioxane is another preferred curable compound. Specifically, the low refractive index layer preferably contains a cured polysilsesquioxane as a binder component. Including a cured polysilsesquioxane as a binder component makes it easier to improve the scratch resistance of the low refractive index layer. Since the cured polysilsesquioxane easily improves the toughness of the entire layer, not just the surface of the layer, it is thought that it is easy to improve the scratch resistance of the low refractive index layer. Furthermore, since the cured polysilsesquioxane has good adhesion to silica, it is thought that it is easy to improve the scratch resistance of the low refractive index layer.

[0104] If the polysilsesquioxane content is too high, the flexural resistance of the anti-reflective material may decrease. For this reason, it is preferable to use polysilsesquioxane in combination with a polyfunctional (meth)acrylate compound. That is, the binder component preferably contains a cured product of a polyfunctional (meth)acrylate compound and a cured product of polysilsesquioxane. The mass ratio of the polyfunctional (meth)acrylate compound to polysilsesquioxane (polyfunctional (meth)acrylate compound: polysilsesquioxane) is preferably 95:5 to 20:80, more preferably 92.5:7.5 to 30:70, and even more preferably 90:10 to 40:60. By keeping the ratio within the above range, it is possible to improve scratch resistance while suppressing a decrease in flexural resistance.

[0105] Polysilsesquioxane is a polymer having a constituent unit represented by the following general formula (1). In formula (1), R represents an organic group. Examples of organic groups include organic groups having reactive groups, which will be described later. The number of constituent units below is preferably 4 to 30. [RSio １．５ ] (1)

[0106] Polysilsesquioxane structures include random structures, ladder structures, and cage structures. Among these, the cage structure is preferred.

[0107] It is preferable that polysilsesquioxane has at least one or more silicon units substituted with a reactive group. Polysilsesquioxane with one or more reactive groups substituted readily reacts with the leveling agent described later, making it easier to fix the leveling agent in the low refractive index layer. For this reason, polysilsesquioxane with one or more reactive groups substituted can easily provide good scratch resistance over a long period of time. In addition, polysilsesquioxane with one or more reactive groups substituted can easily reduce the proportion of siloxane bonds exposed on the surface side of the low refractive index layer, thus improving chemical resistance.

[0108] Reactive groups include (meth)acryloyl groups, vinyl groups, and epoxy groups. Among these, (meth)acryloyl groups are preferred. More specific examples of reactive groups include (meth)acrylates, alkyl (meth)acrylates having 1 to 20 carbon atoms, cycloalkyl epoxides having 3 to 20 carbon atoms, and alkylcycloalkane epoxides having 1 to 10 carbon atoms.

[0109] The functional group equivalent (g / eq) of the reactive groups of polysilsesquioxane is preferably 50 to 1000, and more preferably 100 to 500. By setting the functional group equivalent within the above range, polymerization shrinkage of the low refractive index layer is suppressed, and the leveling agent can be easily fixed in the low refractive index layer.

[0110] Polysilsesquioxane may have at least one or more silicon constituent units substituted with a reactive group, and further, at least one or more silicon constituent units may be substituted with a non-reactive group. Such polysilsesquioxanes can easily reduce the proportion of siloxane bonds exposed on the surface side of the low refractive index layer, thus improving chemical resistance. In addition, polysilsesquioxanes substituted with non-reactive groups can easily suppress polymerization shrinkage of the low refractive index layer. Examples of non-reactive groups include linear or branched alkyl groups having 1 to 20 carbon atoms, cyclohexyl groups having 6 to 20 carbon atoms, and aryl groups having 6 to 20 carbon atoms.

[0111] The weight-average molecular weight of polysilsesquioxane is preferably 5000 or less, more preferably 4000 or less, and even more preferably 3000 or less, while the lower limit is preferably 800 or more, more preferably 900 or more, and even more preferably 1000 or more.

[0112] 《Silane Coupling Agent》 The low refractive index layer preferably contains a silane coupling agent. Examples of silane coupling agents include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, N-(2-aminoethyl-γ-aminopropyl)methyldimethoxysilane, N-(2-aminoethyl-γ-aminopropyl)trimethoxysilane, and N-(2-aminoethyl-γ-aminopropyl)triethoxysilane. To facilitate the linking of hollow silica particles and solid particles via the silane coupling agent, a silane coupling agent in which the spacer portion connecting the organic functional group and the alkoxysilyl group is a long-chain hydrocarbon chain is preferred. By using a long-chain hydrocarbon chain as the spacer portion, the hydrophobicity of the silane coupling agent is improved, which improves the dispersion stability of the particles after linking and improves the stability of the composition. Examples of silane coupling agents having long-chain hydrocarbon chain spacers include 7-octenyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, and N-(2-aminoethyl-8-aminooctyl)trimethoxysilane. The number of carbon atoms in the spacer portion is preferably 6 to 12, and more preferably 8 to 10.

[0113] 《Leveling Agent》 The low refractive index layer preferably contains a leveling agent. The inclusion of a leveling agent in the low refractive index layer improves the surface slipperiness, making it easier to improve scratch resistance. To facilitate the effects described above, a leveling agent having a reactive group is preferred. Examples of reactive groups include (meth)acryloyl groups, vinyl groups, and epoxy groups. Among these, (meth)acryloyl groups are preferred.

[0114] Examples of leveling agents include silicone-based leveling agents and fluorine-based leveling agents. Silicone-based leveling agents may contain small amounts of fluorine atoms. Fluorine-based leveling agents may contain small amounts of silicon atoms.

[0115] If the proportion of leveling agent is too high, the strength of the coating film may decrease, resulting in reduced scratch resistance. For this reason, the proportion of leveling agent is preferably 5% to 35% by mass, more preferably 6% to 25% by mass, and even more preferably 7% to 10% by mass, relative to the total solid content of the low refractive index layer.

[0116] The low refractive index layer may further contain additives such as antistatic agents, antioxidants, surfactants, dispersants, light stabilizers, and ultraviolet absorbers.

[0117] A low refractive index layer can be formed by applying a coating solution for low refractive index layers containing the components and solvents that make up the low refractive index layer, drying it, and curing it by irradiating it with ionizing radiation as needed.

[0118] <Solvents> Examples of solvents include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), 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. The solvent in the low refractive index layer coating solution preferably has a fast evaporation rate as its main component in order to shorten the drying time of the low refractive index layer coating solution. The main component means that it accounts for 50% by mass or more of the total amount of the solvent, preferably 70% by mass or more, and more preferably 75% by mass or more. In this specification, a solvent with a fast evaporation rate means a solvent whose evaporation rate is 100 or more, when the evaporation rate of butyl acetate is set to 100. The evaporation rate of a solvent with a fast evaporation rate is more preferably 120 to 300, and even more preferably 150 to 220. Examples of solvents with a fast evaporation rate include methyl isobutyl ketone (evaporation rate 160), toluene (evaporation rate 200), and methyl ethyl ketone (evaporation rate 370).

[0119] <Other Layers> The anti-reflective member of this disclosure may have layers other than the base material, hard coat layer, and low refractive index layer. Examples of other layers include a high refractive index layer, a conductive layer, and an antistatic layer.

[0120] 《High refractive index layer》 It is preferable to place the high refractive index layer between the hard coat layer and the low refractive index layer. In this specification, "high refractive index layer" means a layer with a refractive index higher than that of the hard coat layer and the low refractive index layer.

[0121] The refractive index of the high refractive index layer is preferably 1.53 or higher at the lower limit, more preferably 1.54 or higher, more preferably 1.55 or higher, and more preferably 1.56 or higher. The upper limit is preferably 1.85 or lower, more preferably 1.80 or lower, more preferably 1.78 or lower, and more preferably 1.77 or lower.

[0122] The high refractive index layer preferably contains a binder component and high refractive index particles. The binder component of the high refractive index layer preferably contains a cured product of a curable resin composition. The ratio of the cured product of the curable resin composition to the total binder component of the high refractive index layer is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 90% by mass or more, and most preferably 100% by mass. Examples of curable resin compositions for the high refractive index layer include thermosetting resin compositions and ionizing radiation-curable resin compositions, with ionizing radiation-curable resin compositions being preferred. Curable resin compositions such as thermosetting resin compositions and ionizing radiation-curable resin compositions are the same as those exemplified for the low refractive index layer. The ionizing radiation-curable compound used in the high refractive index layer preferably contains a polyfunctional (meth)acrylate compound.

[0123] Examples of high refractive index particles include antimony pentoxide, zinc oxide, titanium oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, yttrium oxide, and zirconium oxide.

[0124] The average particle diameter of the high refractive index particles is preferably 2 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more. From the viewpoint of suppressing whitening and transparency, the average particle diameter of the high refractive index particles is preferably 200 nm or less, more preferably 100 nm or less, more preferably 80 nm or less, more preferably 60 nm or less, and even more preferably 30 nm or less. The average particle diameter of the high refractive index particles is calculated from an image of the vertical cross-section of the anti-reflective member taken with a scanning transmission electron microscope. The method for calculating the average particle diameter of the high refractive index particles can be the same as the method for calculating the average particle diameter of the particles contained in the hard coat layer described above. In calculating the average particle diameter of the high refractive index particles, the imaging conditions for the scanning transmission electron microscope are set to an acceleration voltage of 30 kV and a magnification of 100,000x.

[0125] The content of high refractive index particles is preferably 100 parts by mass or more, more preferably 150 parts by mass or more, and even more preferably 250 parts by mass or more, per 100 parts by mass of the binder component, with an upper limit of 500 parts by mass or less, more preferably 400 parts by mass or less, and even more preferably 350 parts by mass or less.

[0126] The upper limit of the high refractive index layer is preferably 200 nm or less, more preferably 185 nm or less, and even more preferably 175 nm or less. The lower limit is preferably 50 nm or more, and more preferably 70 nm or more.

[0127] The high refractive index layer may further contain additives such as leveling agents, antistatic agents, antioxidants, surfactants, dispersants, light stabilizers, and ultraviolet absorbers.

[0128] <Optical Properties> The anti-reflective member preferably has a total light transmittance of 70% or more, more preferably 80% or more, and even more preferably 85% or more, according to JIS K7361-1:1997. The light incident surface when measuring total light transmittance, haze, and transmitted image clarity is the surface on the substrate side. In this specification, total light transmittance, haze, reflectance, a ＊ value, b ＊ The value for transmission image clarity represents the average of 10 measurement points.

[0129] To improve resolution, the anti-reflective material preferably has a haze of 40% or less, more preferably 33% or less, and even more preferably 27% or less, according to JIS K7136:2000. The lower limit of the haze is not particularly limited, but to improve anti-glare properties, it is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more.

[0130] The anti-reflective material preferably has an internal haze of 30% or less, more preferably 25% or less, and even more preferably 20% or less, in order to improve resolution. The lower limit of the internal haze is not particularly limited, but to make it easier to suppress glare, it is preferably 2% or more, more preferably 7% or more, and even more preferably 15% or more.

[0131] Internal haze is measured by the following method: (1) A sample is prepared in which the surface irregularities of the anti-reflective material are smoothed by laminating a transparent sheet to the surface of the anti-reflective material having a low refractive index layer via a transparent adhesive layer. (2) The haze of the sample is measured in accordance with JIS K7136:2000. The measured value is considered to be the internal haze of the anti-reflective material.

[0132] In the present disclosure, a sample is prepared by laminating a black plate to the substrate side of the anti-reflective member via a transparent adhesive layer, and it is preferable that the reflectance measured by the SCI method from the low refractive index layer side of the sample is 3.0% or less. More preferably, the reflectance measured by the SCI method is 2.5% or less, and even more preferably 2.0% or less. There is no particular lower limit to the reflectance measured by the SCI method, but it is preferable to be 0.3% or more in order to easily improve scratch resistance.

[0133] The refractive index difference between the member in contact with the transparent adhesive layer of the sample and the transparent adhesive layer shall be 0.15 or less. Preferably, the refractive index difference shall be 0.10 or less, and more preferably 0.05 or less. The member in contact with the transparent adhesive layer of the sample is, for example, a substrate. The black board shall have a total light transmittance of 1% or less according to JIS K7361-1:1997. Preferably, the total light transmittance of the black board is 0%. The refractive index difference between the resin constituting the black board and the transparent adhesive layer shall be 0.15 or less. Preferably, the refractive index difference shall be 0.10 or less, and more preferably 0.05 or less.

[0134] SCI is an abbreviation for Specular Component Include, and refers to reflected light that contains a component that is specularly reflected from the sample. In this specification, SCI shall be measured in accordance with geometric condition c of JIS Z8722:2009. <Geometric condition c of JIS Z8722:2009> The sample is irradiated uniformly from all directions, and reflected light is received in directions where the angle with the normal to the sample surface is 10° or less. In this case, the received light beam shall not contain rays that are tilted at an angle of 5° or more with respect to its center line. Furthermore, it is desirable that the direction of reception does not coincide with the normal to the sample.

[0135] The anti-reflective member of this disclosure is based on the reflected light measured by the SCI method from the low refractive index layer side of the sample. ＊ Value and b ＊ The value is preferably within the following range: a ＊ The value is preferably between -2 and +5, and more preferably between 0 and +3. ＊ The value is preferably between -12 and -3, and more preferably between -8 and -4.

[0136] In order to improve resolution, the anti-reflective member of this disclosure preferably has a transmitted image clarity of 50% or less, more preferably 45% or less, and even more preferably 40% or less, at an optical comb width of 0.125 mm as specified in JIS K7374:2007. The lower limit of the transmitted image clarity is not particularly limited, but in order to improve anti-glare properties, it is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more.

[0137] <Uneven Shape> In order to obtain good anti-glare properties, the anti-reflective member of this disclosure preferably has an arithmetic mean roughness Ra of 100 nm to 200 nm, and more preferably 110 nm to 190 nm, on the surface opposite the hard coat layer of the low refractive index layer, with a cutoff value of 0.8 mm. The surface opposite the hard coat layer of the low refractive index layer preferably has a ten-point mean roughness RzJIS of 1.0 μm to 3.0 μm, and more preferably 1.5 μm to 2.5 μm, on the surface opposite the hard coat layer of the low refractive index layer, with a cutoff value of 0.8 mm. The maximum height Rz of 1.0 μm to 3.5 μm, and more preferably 1.5 μm to 3.0 μm, on the surface opposite the hard coat layer of the low refractive index layer, with a cutoff value of 0.8 mm. In this disclosure, Ra, RzJIS, and Rz are values ​​measured using a white light interference microscope in accordance with JIS B0601:2001.

[0138] <Size, Shape, etc.> The anti-reflective material 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" means the maximum length when connecting any two points on the anti-reflective material. If the anti-reflective material is rectangular, the diagonal of the rectangle is the maximum diameter. If the anti-reflective material 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 approximately 500 mm to 3000 mm, and the length is approximately 50 m to 5000 m. The anti-reflective material in roll form can be cut into single sheets to match the size of the image display device, etc. When cutting, it is preferable to exclude the roll ends where the physical properties are unstable. The shape of the sheet is also not particularly limited, and may be a polygon such as a triangle, rectangle, or pentagon, or a circle, or a random irregular shape. More specifically, if the anti-reflective material is rectangular, the aspect ratio is not particularly limited as long as it does not pose a problem as a display screen. For example, aspect ratios such as width:height = 1:1, 4:3, 16:10, 16:9, 2:1 are possible.

[0139] [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 either the first transparent protective plate or the second transparent protective plate is the anti-reflective member of the present disclosure described above, and the surface of the anti-reflective member on the low refractive index layer side faces away from the polarizer.

[0140] Polarizing plates are used, for example, in combination with λ / 4 phase difference plates to provide anti-reflective properties. In this case, a λ / 4 phase difference plate is placed on the display element of an image display device, and the polarizing plate is placed on the viewer side of the λ / 4 phase difference plate. For liquid crystal display devices, polarizing plates are used to provide the function of a liquid crystal shutter. In this case, the liquid crystal display device is arranged in the order of lower polarizing plate, liquid crystal display element, and upper polarizing plate from the backlight side, and the absorption axis of the polarizer of the lower polarizing plate and the absorption axis of the polarizer of the upper polarizing plate are arranged orthogonally. In the configuration of a liquid crystal display device, the polarizing plates of this disclosure can be used as the upper polarizing plate and the lower polarizing plate, and it is preferable to use the polarizing plate of this disclosure as the upper polarizing plate. In the upper polarizing plate, it is preferable to use the anti-reflective member of this disclosure as a transparent protective plate on the light emission surface side of the polarizer. In the lower polarizing plate, it is preferable to use the anti-reflective member of this disclosure as a transparent protective plate on the light incidence surface side of the polarizer.

[0141] <Transparent protective plate> The polarizing plate of the present disclosure includes the anti-reflective member of the present disclosure as described above, as at least one of the first transparent protective plate and the second transparent protective plate. A preferred embodiment is in which both the first transparent protective plate and the second transparent protective plate include the anti-reflective member of the present disclosure as described above.

[0142] If one of the first transparent protective plate and the second transparent protective plate includes the anti-reflective member of this disclosure described above, the other transparent protective plate is preferably an optically isotropic transparent protective plate. In this specification, optical isotropy refers to a plane with an in-plane phase difference of 20 nm or less, preferably 10 nm or less, and more preferably 5 nm or less. Acrylic films and triacetylcellulose films are easily given optical isotropy. If one of the first transparent protective plate and the second transparent protective plate includes the anti-reflective member of this disclosure described above, it is preferable that the transparent protective plate on the light-emitting side includes the anti-reflective member of this disclosure described above.

[0143] <Polarizers> 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, which are dyed with iodine or the like and stretched; wire grid-type polarizers consisting of numerous metal wires arranged in parallel; coated polarizers coated with lyotropic liquid crystal or dichroic guest-host material; 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.

[0144] [Image Display Panel] The image display panel 120 of the present disclosure is an image display panel having a display element 110 and an optical film disposed on the light-emitting surface side of the display element 110, wherein the optical film includes the anti-reflective member 100 of the present disclosure described above, and the surface of the anti-reflective member 100 on the low refractive index layer side faces away from the display element 110, and the anti-reflective member 100 is placed on the outermost surface (see Figure 2).

[0145] Examples of display elements include liquid crystal display elements, organic EL display elements and inorganic EL display elements, plasma display elements, and LED display elements such as micro-LED display elements. 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 method, VA method, multi-domain method, OCB method, STN method, TSTN method, etc.

[0146] The image display panel of this disclosure may be an image display panel with a touch panel having a touch panel between the display element and the anti-reflective member. In this case, the anti-reflective member should be placed on the outermost surface of the image display panel with the touch panel, and the surface of the anti-reflective member with the low refractive index layer facing away from the display element should be positioned accordingly.

[0147] The size of the image display panel is not particularly limited, but the maximum diameter is approximately 2 inches to 500 inches. The maximum diameter refers to the maximum length when connecting any two points within the surface of the image display panel.

[0148] [Image Display Device] The image display device of the present disclosure includes the image display panel of the present disclosure described above, and the anti-reflective member is arranged on the outermost surface.

[0149] Preferably, the image display device of this disclosure further comprises a drive control unit electrically connected to the image display panel and a housing that houses the image display panel and the drive control unit, etc. If the display element is a liquid crystal display element, the image display device of this disclosure requires a backlight. The backlight is positioned on the side opposite to the light-emitting surface of the liquid crystal display element.

[0150] The size of the image display device is not particularly limited, but the maximum diameter of the effective display area is approximately 2 inches to 500 inches. The effective display area of ​​an image display device is the area in which an image can be displayed. For example, if the image display device has a housing that surrounds the display element, the area inside the housing is the effective display area. The maximum diameter of the effective display area is defined as the maximum length when connecting any two points within the effective display area. For example, if the effective display area is rectangular, the diagonal of the rectangle is the maximum diameter. If the effective display area is circular, the diameter of the circle is the maximum diameter.

[0151] [Anti-reflective articles] The anti-reflective articles of this disclosure are arranged on a member such that the surface of the anti-reflective member described above, with the low refractive index layer side facing away from the member, and the anti-reflective member is placed on the outermost surface. Preferably, the member and the anti-reflective member are laminated with an adhesive layer in between.

[0152] Examples of components include instrument panels, clocks, display cases, shop windows, and windows. The components may be transparent or opaque, and their color is not particularly limited.

[0153] This disclosure includes the following <1> to <18>. <1> An anti-reflective member having a hard coat layer and a low refractive index layer on a substrate in this order, wherein the low refractive index layer includes a binder component and inorganic particles, the inorganic particles include hollow silica particles and first solid particles, the hollow silica particles are unevenly distributed towards the hard coat layer in the thickness direction of the low refractive index layer, and when the average particle diameter of the hollow silica particles is defined as r and the average particle diameter of the first solid particles is defined as R1, r < R1, the anti-reflective member. <2> The anti-reflective member according to <1>, wherein the ratio of the thickness of the region where the hollow silica particles are unevenly distributed to the thickness of the low refractive index layer is 0.50 or more and 0.90 or less. <3> The anti-reflective member according to <1> or <2>, where the average thickness of the low refractive index layer is defined as d, r < R1 < d, the anti-reflective member. <4> The anti-reflective member according to <3>, where d is 60 nm or more and 155 nm or less. <5> An anti-reflective member according to any one of <1> to <4>, wherein r is 40 nm or more and 100 nm or less. <6> An anti-reflective member according to any one of <1> to <5>, wherein R1 is 50 nm or more and 150 nm or less. <7> An anti-reflective member according to any one of <1> to <6>, wherein R1 / r is greater than 1.0 and 2.0 or less. <8> An anti-reflective member according to any one of <1> to <7>, wherein in the thickness direction of the low refractive index layer, the first solid particles are located in a region where the hollow silica particles are unevenly distributed. <9> An anti-reflective member according to any one of <1> to <8>, wherein the first solid particles are solid alumina particles. <10> An anti-reflective member according to any one of <1> to <9>, wherein the inorganic particles further include second solid particles, and when the average particle diameter of the second solid particles is defined as R2, R2 < r < R1. <11> The anti-reflective member according to any one of <1> to <10>, wherein the binder component includes a cured product of a polyfunctional (meth)acrylate compound. <12> The anti-reflective member according to any one of <1> to <11>, wherein the surface of the hard coat layer on the low refractive index layer side has an uneven shape. <13> The anti-reflective member according to <1> to <12>, wherein the surface of the low refractive index layer opposite to the hard coat layer has an arithmetic mean roughness Ra of 100 nm or more and 200 nm or less as defined in JIS B0601:2013 with a cutoff value of 0.8 mm.<14> The anti-reflective member according to <1> to <13>, wherein the surface of the low refractive index layer opposite to the hard coat layer has a ten-point average roughness RzJIS of 1.0 μm or more and 3.0 μm or less as defined in JIS B0601:2013, with a cutoff value of 0.8 mm. <15> 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 either the first transparent protective plate or the second transparent protective plate is the anti-reflective member according to any of <1> to <14>, and the surface of the anti-reflective member on the low refractive index layer side faces away from the polarizer. <16> An image display panel having a display element and an optical film disposed on the light-emitting surface side of the display element, wherein the optical film includes an anti-reflective member as described in any of <1> to <14>, the surface of the anti-reflective member on the low refractive index layer side faces away from the display element, and the anti-reflective member is placed on the outermost surface. <17> An image display device comprising the image display panel described in <16>, wherein the anti-reflective member is placed on the outermost surface. <18> An anti-reflective article having an anti-reflective member as described in any of <1> to <14> arranged on a member such that the surface of the anti-reflective member on the low refractive index layer side faces away from the member, and the anti-reflective member is placed on the outermost surface.

[0154] Next, the present disclosure will be described in more detail by examples, but the present disclosure is not limited in any way by these examples. Unless otherwise specified, "parts" and "%" are based on mass.

[0155] 1. Measurement and Evaluation The anti-reflective members of the examples and comparative examples were measured and evaluated as follows. 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%. Unless otherwise specified, before starting each measurement and evaluation, the sample to be measured was exposed to the above atmosphere for 30 to 60 minutes. The samples used for each measurement and evaluation were prepared by cutting the anti-reflective members of the examples and comparative examples. The cutting locations were selected from random parts after visually confirming that there were no abnormalities such as dust or scratches.

[0156] 1-1. Presence or Absence of Uneven Distribution of Hollow Silica Particles Sectional samples with exposed vertical cross-sections of the anti-reflective material were prepared according to the procedures in (A1) to (A2) of the main text of the specification. The silicone embedding plate in (A1) was manufactured by Dosaka EM Co., Ltd. The epoxy resin used for embedding in (A1) was a mixture of Herzog's product name "Herzog Epoxy Low Viscosity Main Agent 1571" and Herzog's product name "Herzog Epoxy Hardener II 1552-2" in a 10:2 ratio. The resin used for embedding in (A1) was cured by leaving it at room temperature for 12 hours. The device used to cut the block-shaped embedding sample in (A2) was the Leica Microsystems product name "Ultramicrotome EM UC7". When cutting the block-shaped embedded samples, they were initially roughly cut (coarse trimming), and finally precisely trimmed under the conditions of "SPEED: 0.80 mm / s" and "FEED: 40 nm". The samples for measurement were stained with osmium tetroxide.

[0157] Using the sample prepared above, cross-sectional images of the anti-reflective material were acquired. A scanning transmission electron microscope, model S-4800, manufactured by Hitachi High-Technologies Corporation, was used to acquire images under conditions of an acceleration voltage of 30.0 kV and a magnification of 100,000x.

[0158] In steps 1 to 3 of the specification, it was determined whether or not hollow silica particles were unevenly distributed towards the hard coat layer in the thickness direction of the low refractive index layer. First, following procedures (1) to (5) of the specification, the "side of the low refractive index layer facing the hard coat layer," "regions where hollow silica particles do not exist," "regions where hollow silica particles exist," and "the side of the low refractive index layer opposite the hard coat layer" were determined. The ratio of the thickness of the region where hollow silica particles exist to the thickness of the low refractive index layer was also calculated. As image analysis software for determination, the open-source programming language "Python" image processing libraries "Scikit-image" and "OpenCV" were used. The image plotting library "Matplotlib" was used to create two-tone images, corrected images, extracted images, and superimposed images. The numerical calculation libraries "Numpy," "Scippy," and "math" were used for numerical calculations.

[0159] Specifically, in procedure (1), the first image was imported into Scikit-image and Gaussian filtering was performed. In the Gaussian filtering, the standard deviation σ was set to 5. Next, two thresholds for trinarizing the image after the Gaussian filtering were calculated using the multi-Otsu method, and the image after the Gaussian filtering was converted to a two-tone image using the threshold with the higher brightness. In the two-tone image, the coordinates of the pixels corresponding to the "side opposite the hard coat layer of the low refractive index layer" were obtained, and the obtained coordinates were fitted with a linear function to determine that the resulting line was the "side opposite the hard coat layer of the low refractive index layer". In addition, the inclination angle of the "side opposite the hard coat layer of the low refractive index layer" with respect to the upper and lower edges of the first image was obtained. If the absolute value of the obtained inclination angle was within 2 degrees, the first image was imported into Scikit-image again. The tilt angle obtained was input to Scikit-image, and the first image was rotated so that the tilt angle became 0 degrees to obtain a corrected image. The above process was performed again on this corrected image to determine the "side opposite the hard coat layer of the low refractive index layer," and the coordinates Y1 of the intercept between the left edge of the first image and the "side opposite the hard coat layer of the low refractive index layer" were obtained. The coordinates of the intercept were obtained as an integer rounded to the nearest integer. If the absolute value of the tilt angle exceeded 2 degrees, the subsequent steps (2) to (5) were not performed, the image was excluded from the determination, and step (1) was performed using a different image as the first image.

[0160] In procedure (2), the corrected image was imported into Scikit-image and processed to enhance contrast. Specifically, a Gaussian filter was applied to the corrected image with a standard deviation σ of 1.5 to remove noise. Next, a circular area with a radius of 5 pixels was set with each pixel as the center. If the pixel value of the central pixel was close to the maximum pixel value within the circular area (i.e., the local maximum pixel value), the pixel value of the central pixel was replaced with the local maximum pixel value. If the pixel value of the central pixel was close to the minimum pixel value within the circular area (i.e., the local minimum pixel value), the pixel value of the central pixel was replaced with the local minimum pixel value. This series of processes was performed five times to enhance the contrast of the corrected image. After that, a Gaussian filter was applied with a standard deviation σ of 3. The Canny method was applied to the image after the Gaussian filter was applied to detect contour lines corresponding to hollow silica particles in the image. The conditions for the Canny method were set to a standard deviation of σ = 3, and the upper limit of the hysteresis thresholding process was set to 0.12 and the lower limit to 0.01. Next, a Fill Hole process was performed, and the area enclosed by the contour line was displayed in white. Furthermore, from the white areas shown after the Fill Hole process, those with a roundness of more than 0.8 were extracted, and the extracted image was obtained.

[0161] In procedure (3), the "side of the low refractive index layer opposite to the hard coat layer" obtained in procedure (1) was used to identify the thickness direction of the low refractive index layer in the extracted image obtained in procedure (2). The extracted image was divided into 1-pixel sections in the thickness direction and in the direction perpendicular to the thickness direction. That is, one section was defined as 1 pixel. Next, coordinates corresponding to the sections in the thickness direction were assigned to the left edge of the extracted image. Then, for each section in the thickness direction, the number of sections corresponding to hollow silica particles appearing in the direction perpendicular to it was calculated.

[0162] In procedure (4), a superimposed image was obtained by superimposing the extracted image obtained in procedure (2) with a bar graph that reflected the positional information (coordinates in the thickness direction and information on the number of sections in the region corresponding to hollow silica particles) obtained in procedure (3). In the superimposed image, following the procedure described in the main body of the specification, coordinate Y2 was obtained, which corresponds to the boundary between the last section where the number of sections in the orthogonal direction exceeds 0 and the section adjacent to this section on the hard coat layer side where the number of sections in the orthogonal direction is 0. This coordinate was fitted with a linear function, and the line obtained by the fitting was determined to be the "side of the low refractive index layer on the hard coat layer side". The region between the "side of the low refractive index layer on the hard coat layer side" and the "side of the low refractive index layer opposite to the hard coat layer" obtained in procedure (1) was identified as the low refractive index layer. Within the low refractive index layer, the maximum value N of the number of sections in the region corresponding to hollow silica particles was obtained. In addition, following the means described in the main body of the specification, coordinate Y3 was obtained, which corresponds to the boundary between the section where the number of sections in the region corresponding to hollow silica particles exceeds 7.5% of the maximum value N and the section immediately preceding it. In procedure (5), the obtained coordinates Y1, Y2, and Y3 were used to calculate the ratio of the thickness of the region containing hollow silica particles to the thickness of the low refractive index layer in the first image.

[0163] For the second to tenth images, coordinates Y1 to Y3 were obtained using the same procedure as described above, and the ratio of the thickness of the region containing hollow silica particles to the thickness of the low refractive index layer was calculated. In accordance with the specification, the ratio of the thickness of the region where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer was calculated for the examples and comparative examples. In Table 1, the "ratio of the thickness of the region where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer" is referred to as the "thickness ratio". A ratio of 0.85 or less to the thickness of the region where hollow silica particles are unevenly distributed was rated as "A", a ratio greater than 0.85 and 0.90 or less was rated as "B", and a ratio greater than 0.90 was rated as "C".

[0164] 1-2. Determination of the position of the first solid silica particle Following procedures (i) to (vii) in the main text of the specification, it was determined whether the first solid particle was located in a region where hollow silica particles were unevenly distributed. The open-source libraries "Scikit-image" and "OpenCV" were used as image analysis software for the determination. The Python image plotting library "Matplotlib" was used to create the cropped image, distance map, binarized images A and B, and label image. The Python numerical calculation libraries "Numpy," "Scipy," and "math" were used for numerical calculations. The determination used the corrected images of the first to tenth images obtained in 1-1, and the coordinates Y1 to Y3. In the adaptive thresholding process in procedure (ii), the neighboring region size was set to 101 pixels. Furthermore, the pixel values ​​of each region were weighted with a Gaussian function with a standard deviation σ of 20, and the weighted mean was used as the threshold. In the Watershed process of step (iv), the detection of pixels with locally local maximum values ​​was performed using the peak_local_max function stored in Scikit-image. The parameter "footprint," which indicates the local region for searching for local maximums, was set to a 5x5 pixel square. In addition, in the binarized image A obtained in step (ii), the detection of pixels with locally local maximum values ​​was performed only in the areas corresponding to the white areas (pixel value of 1). In step (v), the value calculated as a circle with radius r of 30 pixels was set as the threshold for the number of pixels. In the moment calculation in step (v), the "moments function" implemented in the library "OpenCV" was used. According to procedure (vii), those determined to be "located in the region where hollow silica particles are unevenly distributed in the thickness direction of the low refractive index layer" were designated as "A," and those not determined to be "located in the region where hollow silica particles are unevenly distributed in the thickness direction of the low refractive index layer" were designated as "C."

[0165] 1-3. Scratch Resistance <Break-in Test> A polyethylene terephthalate film (100 μm thick) was attached to the measurement stage of the measuring device (product name "AB-301", manufactured by Tester Sangyo Co., Ltd.). Next, steel wool (#0000, manufactured by Nippon Steel Wool Co., Ltd., product name "Bonstar B-204") was set up. The steel wool was brought into contact with the surface of the polyethylene terephthalate film, and the steel wool was moved back and forth 300 times under the conditions of a load of 300 g, a moving speed of 80 mm / second, and a moving distance of 80 mm per reciprocating motion. The contact area between the steel wool and the polyethylene terephthalate film was 4 cm². ２ The following was done. <Scratch Resistance Test> Samples of the anti-reflective material of the examples and comparative examples were prepared by cutting them into 3 cm x 10 cm pieces. The cutting locations were selected from random parts after visually confirming that there were no abnormal points such as dust or scratches. The samples were placed on the measurement stage of the measuring device with the low refractive index layer side facing upwards. The steel wool was brought into contact with the surface of the low refractive index layer, and the steel wool was moved back and forth 100 times under the conditions of a load of 500 g, a moving speed of 4800 mm / min, and a moving distance of 80 mm per round trip. The contact area between the steel wool and the sample was 4 cm². ２The following was done. <Contact angle of pure water before and after the test> The contact angle of the anti-reflective material with pure water was measured before and after the scratch resistance test. Specifically, it was measured using a microscopic contact angle meter (product name "DropMaster300", manufactured by Kyowa Interface Science Co., Ltd.) according to the drop method described in JIS R3257:1999. The pure water contact angle was the average value of 5 points. The amount of pure water dropped was 1 μL. Samples with a pure water contact angle of 100 degrees or more after the test were classified as "A", and samples with a pure water contact angle of less than 100 degrees after the test were classified as "C". <Change in color before and after the test> Samples were prepared by laminating a black polyethylene terephthalate film to the base material side of the anti-reflective material before and after the scratch resistance test. The color of the samples was observed from various directions in a bright room environment of 500 lux to 1500 lux. Twenty people aged 20 to 50 years old were evaluated according to the following criteria. S: Zero or fewer people reported that the color of the sample after the test was different from the sample before the test. A: One to three people reported that the color of the sample after the test was different from the sample before the test. B: Four to six people reported that the color of the sample after the test was different from the sample before the test. B － C: 7 to 9 people answered that the color of the sample after the test was different from the sample before the test. C: 10 or more people answered that the color of the sample after the test was different from the sample before the test.

[0166] 1-4. Samples of the anti-reflective material of the pencil hardness examples and comparative examples were prepared by cutting them to a size of 5 cm x 10 cm. In accordance with JIS K5600-5-4:1999, the pencil hardness of the low refractive index layer side of the sample was measured under conditions of a load of 500 g and a speed of 1.4 mm / sec. A pencil hardness tester (model number: NP type pencil scratch coating hardness tester) manufactured by Toyo Seiki Co., Ltd. was used for the measurement. Both ends of the cut sample were attached to the base of the pencil hardness tester using mending tape (3M, model number "810-3-18"). Five pencil hardness tests were performed, and the hardness at which no abnormalities such as scratches were observed in four or more tests was taken as the pencil hardness value for each sample. For example, if a 2H pencil is used and no abnormalities are observed in four out of five tests, the pencil hardness of the anti-reflective material is 2H. Regarding abnormalities, discoloration was not included, and only scratches and dents were checked. A pencil with a hardness of 2H or higher is considered acceptable.

[0167] 1-5. The anti-reflective materials of the anti-glare examples and comparative examples were cut into 5cm x 5cm pieces. The cutting locations were selected randomly after visually confirming that there were no abnormalities such as dust or scratches. A sample was prepared by attaching the substrate side of the cut optical film to a black board (Kuraray Co., Ltd., product name: Comoglass DFA2CG 502K (black) series, thickness 2mm) measuring 5cm x 5cm, via a Panac Co., Ltd. optical transparent adhesive sheet (product name: Panaclean PD-S1, thickness 25μm). In a brightly lit room, the sample was placed on a horizontal stand 70cm high with the low refractive index layer facing upwards. The sample was positioned so that it was approximately directly below the illumination light. The sample was observed from the front (however, the observer was not obstructed by the illumination light), and the reflection of the illumination light on the uneven surface was evaluated according to the following evaluation criteria. The lighting used was an Hf32 type straight tube tri-wavelength daylight white fluorescent lamp, positioned 2m vertically above the horizontal platform. The illuminance on the uneven surface of the sample was evaluated within the range of 500 lux to 1000 lux. The observer's line of sight was approximately 120cm from the floor. The observer was a person in their 30s. <Evaluation Criteria> A: No outline of the light source, and the position is not discernible B: No outline of the light source, but the position is vaguely discernible C: The outline and position of the light source are vaguely discernible D: The outline of the light source is not very blurred, and the position is clearly discernible

[0168] 1-6. Reflectance, a ＊ value, b ＊ From the low refractive index layer side of the sample prepared with values ​​1-4, the reflectance by the SCI method and the a based on the reflected light measured by the SCI method are obtained. ＊ Value and b ＊ The values ​​were measured. The measuring device used was a spectrophotometer manufactured by Konica Minolta (product name: CM-600d). The measuring device conforms to geometric condition c of JIS Z8722:2009. <Measurement conditions> Main light source: D65 Light source 2: None Field of view: 2 degrees Color system: Yxy Color difference formula: ΔE ＊ ab

[0169] 1-7. Total light transmittance, haze, internal haze. The anti-reflective materials of the examples and comparative examples were cut to 10 cm x 10 cm to prepare samples for measurement. 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 each sample under the following conditions. The light incident surface was the substrate side. A sample was prepared in which the surface irregularities were flattened by attaching an 80 μm thick TAC film (0% internal haze) to the low refractive index layer side of the sample via a transparent adhesive, thereby eliminating the influence of haze caused by the surface shape. The haze of the prepared sample was measured, and the obtained value was defined as the internal haze. <Conditions> In order to stabilize the light source, calibration was performed without setting anything in the inlet opening where the measurement sample is placed, after waiting for at least 15 minutes after turning on the power switch of the device in advance. Subsequently, the measurement sample was placed in the entrance opening, and the total light transmittance and haze were measured. The light incident surface during measurement was the substrate side.

[0170] 1-8. Transmitted Image Clarity Samples for measurement were prepared by cutting the anti-reflective materials of the examples and comparative examples into 10 cm x 10 cm sections. The cutting locations were selected randomly after visually confirming that there were no abnormalities such as dust or scratches. The transmitted image clarity of each sample was measured using a Suga Test Instruments Co., Ltd. image clarity meter (product name: ICM-1T) at an optical comb width of 0.125 mm according to JIS K7374:2007. The light incident surface was the substrate side.

[0171] 1-9. Arithmetic mean roughness (Ra), ten-point mean roughness (RzJIS), maximum height (Rz) Test specimens were prepared by cutting the anti-reflective materials of Examples 2-5 and Comparative Examples 1-2 into 10cm x 10cm pieces. Two random locations were selected for cutting after visual inspection to ensure there were no abnormalities such as dust or scratches. A measurement sample was prepared by attaching the substrate side of each cut test specimen to a 10cm x 10cm black board (Kuraray Co., Ltd., product name: Comoglass DFA2CG 502K (black) series, thickness 2mm) via a Panac Co., Ltd. optical transparent adhesive sheet (product name: Panaclean PD-S1, thickness 25μm). The arithmetic mean roughness (Ra), ten-point mean roughness (RzJIS), and maximum height (Rz) of the surface on the low refractive index side of the prepared sample were measured using a white-light interference microscope (Zygo, product name "New View 7300") under the following conditions. As measurement software, Zygo's "MetroPro ver 9.0.10 (64-bit) Microscope Stitching Application" was used to automatically stitch together multiple images for measurement. The analysis was performed using MetroPro ver 9.0.10 (64-bit) Microscope Application. <Measurement Conditions> Objective lens: 10x ImageZoom: 2x Filter: None-BandPass Cutoff value: 0.8 mm Measurement range: 0.25 mm x 0.25 mm The average values ​​of Ra, RzJIS, and Rz measured for two measurement samples were used as the Ra, RzJIS, and Rz values ​​for the anti-reflective members of the examples and comparative examples.

[0172] 2. Fabrication of anti-reflective material [Example 1] A hard coat coating liquid 1 was applied to a polyethylene terephthalate film with a thickness of 50 μm, and then dried at 70°C for 1 minute to evaporate the solvent. Subsequently, in a nitrogen atmosphere with an oxygen concentration of 200 ppm or less, the integrated light intensity was 50 mJ / cm². ２ A hard coat layer with a dry thickness of 6 μm was formed by ultraviolet irradiation. Next, a low refractive index layer coating solution 1 was applied to the hard coat layer, and the solvent was evaporated by drying at 70°C for 60 seconds. Subsequently, in a nitrogen atmosphere with an oxygen concentration of 200 ppm or less, an integrated light intensity of 400 mJ / cm² was applied. ２By irradiating with ultraviolet light, a low refractive index layer with a dry thickness of 120 nm was formed, and the anti-reflective member of Example 1 was obtained.

[0173] <Coating liquid 1 for hard coat layer> ・Urethane acrylate 85 parts by mass (Tokushiki Co., Ltd., product name "AU-3110") ・Polypropylene glycol acrylate 15 parts by mass (Shin Nakamura Chemical Co., Ltd., product name "APG-200") ・Photopolymerization initiator 6 parts by mass (IGM Resins, Inc., product name "Omnirad 184") ・Silica particles 200 parts by mass (Solid content 30% by mass, solvent: MIBK, average primary particle size: 20 nm) ・Leveling agent 0.15 parts by mass (BYK Co., Ltd., product name "BYK-331") ・Solvent 300 parts by mass (methyl ethyl ketone)

[0174] <Coating solution 1 for low refractive index layer> ・100 parts by mass of pentaerythritol triacrylate ・4 parts by mass of photopolymerization initiator (IGM Resins, trade name "Omnirad 184") ・825 parts by mass of inorganic particle dispersion obtained in the first preparation below (The inorganic particle dispersion contains 150 parts by mass of hollow silica particles with an average particle diameter of 60 nm and 15 parts by mass of solid silica particles as first solid particles with an average particle diameter of 80 nm.) ・128.6 parts by mass of fluorine-based leveling agent (Shin-Etsu Chemical Co., Ltd., trade name: KY1211, solid content 20% by mass) ・6862 parts by mass of methyl isobutyl ketone ・1906 parts by mass of propylene glycol monomethyl ether acetate

[0175] <First Preparation> 90 parts by mass of hollow silica particles (average particle size: 60 nm) and 9 parts by mass of solid silica particles (average particle size: 80 nm) were dispersed in 401 parts by mass of methyl isobutyl ketone to obtain dispersion 1. To 9 parts by mass of silane coupling agent (8-methacryloxyoctyltrimethoxysilane, trade name KBM-5803, Shin-Etsu Chemical Co., Ltd.), 1.9 parts by mass of methanol, 1.2 parts by mass of pure water, and 0.05 parts by mass of 0.1 mol / L hydrochloric acid water were added to prepare the reaction solution. After stirring the reaction solution at room temperature for 30 minutes, 500 parts by mass of dispersion 1 were added. Next, the reaction solution to which dispersion 1 had been added was heated to 50°C and stirred at 50°C for 8 hours. Then, the hollow silica particles and solid silica particles were settled by centrifugation, the supernatant was removed, and the hollow silica particles and solid silica particles were washed. Next, methyl isobutyl ketone was added to achieve a solid content of 20% by mass, and an inorganic particle dispersion for Example 1 containing hollow silica particles and solid silica particles was prepared. The first preparation described above satisfies the conditions of the methods B1-1 and B1-2 in the main text of the specification.

[0176] [Examples 2-7] In the first preparation, the type and amount of inorganic particles in the coating solution 1 for the low refractive index layer were changed to the conditions shown in Table 1 by changing the type and amount of inorganic particles. Except for the changes described above, the anti-reflective members of Examples 2-7 were obtained in the same manner as in Example 1.

[0177] [Comparative Example 1] The inorganic particle dispersion was modified to the second preparation described below. In the second preparation, the type and amount of inorganic particles were changed to the conditions in Table 1 by changing the type and amount of inorganic particles in the coating solution 1 for the low refractive index layer. Except for the changes described above, the anti-reflective member of Comparative Example 1 was obtained in the same manner as in Example 1.

[0178] <Second Preparation> To 100 parts by mass of hollow silica particles (average particle size: 60 nm), 9 parts by mass of silane coupling agent (8-methacryloxyoctyltrimethoxysilane, trade name KBM-5803, Shin-Etsu Chemical Co., Ltd.), 1.9 parts by mass of methanol, 1.2 parts by mass of pure water, 0.05 parts by mass of 0.1 mol / L hydrochloric acid water, and 400 parts by mass of methyl isobutyl ketone were added to prepare the reaction solution. The reaction solution was heated to 50°C and stirred at 50°C for 8 hours. Next, the hollow silica particles were allowed to settle by centrifugation, the supernatant was removed, and the hollow silica particles were washed. Through these steps, hollow silica particles surface-treated with the silane coupling agent were obtained. The same procedure as for the hollow silica particles was followed for 100 parts by mass of solid silica particles (average particle size: 12 nm) to obtain solid silica particles surface-treated with the silane coupling agent. Next, methyl isobutyl ketone was added to 150 parts by mass of hollow silica particles and 75 parts by mass of solid silica particles to prepare an inorganic particle dispersion for Comparative Example 1 containing hollow silica particles and solid silica particles, so that the solid content was 20% by mass. The second preparation described above does not satisfy the conditions of the methods B1-1 and B1-2 in the main text of the specification.

[0179] [Comparative Examples 2-4] In the second preparation, the type and amount of inorganic particles in the coating solution 1 for the low refractive index layer were changed to the conditions shown in Table 1 by changing the type and amount of inorganic particles. Except for the changes described above, the anti-reflective members of Comparative Examples 2-4 were obtained in the same manner as in Comparative Example 1.

[0180]

[0181] In all of the anti-reflective members of the examples, the ratio of the thickness of the region where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer was 0.90 or less. In other words, in the examples, it can be said that the hollow silica particles are unevenly distributed towards the hard coat layer in the thickness direction of the low refractive index layer. From the results in Table 1, it can be confirmed that the anti-reflective members of the examples can achieve good scratch resistance. On the other hand, in the anti-reflective members of Comparative Examples 1 to 3, the ratio of the thickness of the region where hollow silica particles are unevenly distributed to the thickness of the low refractive index layer exceeded 0.90, confirming that the particles are not unevenly distributed. It can be confirmed that the anti-reflective members of Comparative Examples 1 to 3 have poor scratch resistance because the hollow silica particles are not unevenly distributed towards the hard coat layer. In the anti-reflective members of Comparative Examples 1 to 3, the hollow silica particles and solid particles are not connected via a silane coupling agent, so it is presumed that during the drying process of the coating film, the hollow silica particles with a lower specific gravity diffuse towards the air interface, while the solid particles with a higher specific gravity move towards the hard coat layer, thus preventing the formation of a region where hollow silica is unevenly distributed. In Comparative Example 4, the anti-reflective material has hollow silica particles unevenly distributed on the hard coat layer side, but does not contain the first solid particles. Therefore, Comparative Example 4 has inferior scratch resistance compared to the example.

[0182] 10: Substrate 20: Hard coat layer 30: Low refractive index layer 31: Binder component 32: Hollow silica particles 33: First solid particles 34: Second solid particles 100: Anti-reflective material S: Region where hollow silica particles are unevenly distributed 110: Display element 120: Image display panel

Claims

1. An anti-reflective member having a hard coat layer and a low refractive index layer on a substrate in that order, wherein the low refractive index layer contains a binder component and inorganic particles, the inorganic particles include hollow silica particles and first solid particles, in the thickness direction of the low refractive index layer the hollow silica particles are biased toward the hard coat layer, and when the average particle diameter of the hollow silica particles is defined as r and the average particle diameter of the first solid particles is defined as R1, r < R1.

2. The anti-reflective member according to claim 1, wherein the ratio of the thickness of the region in which the hollow silica particles are unevenly distributed to the thickness of the low refractive index layer is 0.50 or more and 0.90 or less.

3. The anti-reflective member according to claim 1, wherein when the average thickness of the low refractive index layer is defined as d, r < R1 < d.

4. The anti-reflective member according to claim 3, wherein d is 60 nm or more and 155 nm or less.

5. The anti-reflective member according to claim 1, wherein r is 40 nm or more and 100 nm or less.

6. The anti-reflective member according to claim 1, wherein R1 is 50 nm or more and 150 nm or less.

7. The anti-reflective member according to claim 1, wherein R1 / r is greater than 1.0 and less than or equal to 2.

0.

8. The anti-reflective member according to claim 1, wherein in the thickness direction of the low refractive index layer, the first solid particles are located in a region where the hollow silica particles are unevenly distributed.

9. The anti-reflective member according to claim 1, wherein the first solid particle is a solid alumina particle.

10. The anti-reflective member according to claim 1, wherein the inorganic particles further include a second solid particle, and when the average particle diameter of the second solid particle is defined as R2, R2 < r < R1.

11. The anti-reflective member according to claim 1, wherein the binder component includes a cured product of a polyfunctional (meth)acrylate compound.

12. The anti-reflective member according to claim 1, wherein the surface of the hard coat layer on the low refractive index layer side has an uneven shape.

13. The anti-reflective member according to claim 1, wherein the surface of the low refractive index layer opposite to the hard coat layer has an arithmetic mean roughness Ra of 100 nm or more and 200 nm or less as defined in JIS B0601:2013, with a cutoff value of 0.8 mm.

14. The anti-reflective member according to claim 1, wherein the surface of the low refractive index layer opposite to the hard coat layer has a ten-point average roughness RzJIS of 1.0 μm or more and 3.0 μm or less as defined in JIS B0601:2013, with a cutoff value of 0.8 mm.

15. 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 either the first transparent protective plate or the second transparent protective plate is an anti-reflective member according to any one of claims 1 to 14, and the surface of the anti-reflective member on the low refractive index layer side faces away from the polarizer.

16. An image display panel having a display element and an optical film disposed on the light-emitting surface side of the display element, wherein the optical film includes an anti-reflective member as described in any one of claims 1 to 14, the surface of the anti-reflective member facing the low refractive index layer side faces away from the display element, and the anti-reflective member is placed on the outermost surface.

17. An image display device comprising the image display panel described in claim 16, wherein the anti-reflective member is disposed on the outermost surface.

18. An anti-reflective article comprising an anti-reflective member according to any one of claims 1 to 14, arranged on a member such that the surface of the anti-reflective member with the low refractive index layer facing away from the member, and the anti-reflective member being placed on the outermost surface.

Images