Optical laminates, polarizing plates, display panels, and image display devices

Abstract

To provide an optical laminate that has anti-reflective properties while also possessing excellent scratch resistance. [Solution] An optical laminate comprising a light-transmitting substrate on one surface, wherein at least an anti-glare layer and a low refractive index layer are laminated in this order, characterized in that when the arithmetic mean roughness Ra and the ten-point mean roughness Rz of the surface irregularities in any 5 μm square region of the surface of the low refractive index layer are measured, Ra is 4 nm or less and Rz is 60 nm or less.

Description

[Technical Field]

[0001] The present invention relates to an optical laminate, a polarizing plate, a display panel, and an image display device. [Background technology]

[0002] Image display devices such as liquid crystal displays (LCDs), cathode ray tube displays (CRTs), plasma displays (PDPs), electroluminescent displays (ELDs), and field emission displays (FEDs) typically have an anti-glare film with an uneven surface or an anti-reflective optical laminate with an anti-reflective layer on its surface to suppress reflections of the observer and their background. Such anti-reflective optical laminates suppress image reflections and reduce reflectivity by scattering and interfering with light.

[0003] One known type of anti-reflective optical laminate is one in which an anti-glare layer with an uneven surface is formed on the surface of a transparent substrate, and a low refractive index layer is placed on top of it. Such optical laminates are transported and delivered in packaging materials, but because the protrusions of the anti-glare layer's uneven surface are mainly located on the surface of the low refractive index layer, it was thought that when the optical laminate and the packaging material come into contact, it would be a point contact, and the surface of the low refractive index layer would be less likely to be scratched. However, in reality, problems arose such as scratches caused by friction between the optical laminate and the packaging material. Therefore, there is a growing demand for improved scratch resistance in optical laminates.

[0004] Conventional optical laminates have been disclosed for improving scratch resistance by, for example, using a compound having polymerizable unsaturated groups in the anti-glare layer to impart hardness to the anti-glare layer, or by incorporating inorganic fine particles into the low refractive index layer to impart hardness to the low refractive index layer (see, for example, Patent Document 1).

[0005] However, conventional optical laminates do not offer sufficient scratch resistance, and there has been a need for optical laminates with improved scratch resistance. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2015-004979 [Overview of the project] [Problems that the invention aims to solve]

[0007] In view of the above situation, the present invention aims to provide an optical laminate that has anti-reflective properties while also possessing excellent scratch resistance. [Means for solving the problem]

[0008] The present invention relates to an optical laminate in which an anti-glare layer and a low refractive index layer are laminated in this order on one surface of a light-transmitting substrate, characterized in that when the arithmetic mean roughness Ra and the ten-point mean roughness Rz of the surface irregularities in any 5 μm square region of the surface of the low refractive index layer are measured, Ra is 4 nm or less and Rz is 60 nm or less (hereinafter also referred to as the first invention). Furthermore, the present invention is an optical laminate in which an anti-glare layer and a low refractive index layer are laminated in this order on one surface of a light-transmitting substrate, wherein when the arithmetic mean roughness Ra and the ten-point mean roughness Rz of the surface irregularities in any 5 μm square region of the surface of the low refractive index layer are measured, Ra is 1.5 nm or less and Rz is 30 nm or less, and the hardness when an indenter is pressed 300 nm in by the nanoindentation method is higher than the hardness when an indenter is pressed 30 nm in by the nanoindentation method (hereinafter also referred to as the second present invention). In the following description, when the optical laminate of the first invention and the optical laminate of the second invention are not distinguished, they will be referred to as "the optical laminate of the present invention."

[0009] In the first optical laminate of the present invention, it is preferable that the hardness of the surface of the low refractive index layer, measured by nanoindentation at an indentation depth of 30 nm, is 440 MPa or higher. In the optical laminate of the present invention, the low refractive index layer preferably contains hollow silica fine particles. Furthermore, the present invention is also a polarizing plate comprising a polarizing element, characterized in that the optical laminate of the present invention is provided on the surface of the polarizing element. Furthermore, the present invention is also a display panel characterized by comprising the optical laminate of the present invention or the polarizing plate of the present invention. Furthermore, the present invention is also an image display device characterized by comprising the optical laminate of the present invention or the polarizing plate of the present invention. The present invention will be described in detail below.

[0010] The present inventors have diligently studied methods for imparting scratch resistance to an optical laminate having an anti-glare layer and a low refractive index layer on one surface of a light-transmitting substrate. As a result, they have found that the scratch resistance of the optical laminate can be improved by imparting hardness to the low refractive index layer located on the surface, imparting flatness to the low refractive index layer, imparting slipperiness to the surface of the low refractive index layer, and imparting interlayer adhesion between the low refractive index layer and the anti-glare layer. The inventors then conducted a detailed observation of scratches occurring on the surface of conventional optical laminates comprising an anti-glare layer and a low refractive index layer, and found that scratches occurred regardless of the uneven surface shape. Specifically, there were two modes of scratching: one in which the low refractive index layer was scraped away, reducing its thickness and changing the interference color produced by the interference of reflected light from each layer of the optical laminate having the low refractive index layer; and the other in which the entire low refractive index layer was scraped away, resulting in scratches. In other words, it was found that the uneven surface shape of the low refractive index layer with the anti-glare layer underneath made contact with other surfaces not at a point, but surprisingly, across the entire surface. The problem of the scratch resistance of an optical laminate having such an antiglare layer and a low refractive index layer is a particularly prominent problem in the case of an optical laminate for a large-screen display, where high transparency is essential and excellent antiglare properties are required because a clear image is demanded. Furthermore, as a result of a detailed examination of the mechanism causing the above problem, when the surface of the low refractive index layer comes into contact with a packaging material or the like, very fine irregularities on the surface of the low refractive index layer (various shapes on the surface) affected by fine particles or the like in the low refractive index layer serve as a trigger, and when an external force is applied to the low refractive index layer by rubbing against the surface of another article such as a packaging material, it is presumed that the low refractive index layer is scratched or the entire layer is peeled off. As a result of such examination, in order to improve the scratch resistance of an optical laminate having an antiglare layer and a low refractive index layer, it was considered that a state in which there is no trigger for peeling occurs in the surface portion of the low refractive index layer that comes into contact in the above-described aspect, that is, a finer and flatter texture is less likely to be damaged. And, in order to control the texture state, that is, the flatness, of the surface of the low refractive index layer on a surface with irregularities, it was conceived that it is necessary to examine the flatness in a microscopic field of view where the influence of the convex portions, particularly the convex portions, of the irregularities on the surface of the low refractive index layer is small. Thus, the inventors of the present invention focused on the surface of the low refractive index layer when viewed in a microscopic field of view, and found that by extremely flattening the surface, excellent scratch resistance can be imparted, and the present invention has been completed.

[0011] The optical laminate of the present invention has at least an antiglare layer and a low refractive index layer formed in this order on a light-transmissive substrate. The above low refractive index layer means a layer having a refractive index lower than that of the light-transmissive substrate, antiglare layer, and other components other than the low refractive index layer that constitute the optical laminate of the present invention. The arithmetic mean roughness Ra, ten-point mean roughness Rz of the irregularities, and hardness measured by the nanoindentation method of the surface of the low refractive index layer described later were measured for an optical laminate in which at least an antiglare layer and a low refractive index layer were laminated in this order on one surface of the light-transmissive substrate. In addition, the layer structure of the above optical laminate can be suitably observed in cross section at magnifications of 1000 to 20,000 times by using STEM.

[0012] Note that the lower the unevenness height of the surface of the above low refractive index layer, the flatter the surface of the low refractive index layer can be said to be. The arithmetic mean roughness Ra and the ten-point mean roughness Rz of the unevenness serve as indicators of the unevenness height of the surface of the low refractive index layer. Thus, in the present invention, Ra and Rz are used to judge the texture and flatness of the surface of the low refractive index layer. Although Ra is a parameter with an unknown actual shape, it can show the average height of the entire texture of various microscopic shapes existing on the surface of the target low refractive index layer, and the height of the entire texture can be controlled. In addition, Rz is the average value between the highest and lowest points in the texture of the surface of the low refractive index layer. If only Ra is considered, it is only the result of averaging the texture of the surface of the low refractive index layer, so there is a possibility that sudden high convex portions or low concave portions cannot be discriminated. Such unevenness can cause scratches, resulting in insufficient control of the texture of the surface of the low refractive index layer. Therefore, in the present invention, in addition to the above Ra, the maximum allowable height and the maximum allowable depth are controlled by Rz, and as a result, control of such sudden convex portions and concave portions becomes possible.

[0013] In the optical laminate of the first aspect of the present invention, the above low refractive index layer is extremely excellent in flatness. Specifically, when measuring the arithmetic mean roughness Ra of the unevenness and the ten-point mean roughness Rz of the unevenness defined in JIS B0601 (2001) in an arbitrary 5 μm square region on the surface of the above low refractive index layer, the above Ra is 4 nm or less and the above Rz is 60 nm or less. In the optical laminate of the first aspect of the present invention, if the above Ra exceeds 4 nm or the above Rz exceeds 60 nm, the flatness of the optical laminate of the present invention is insufficient and the abrasion resistance is inadequate. In other words, in the first optical laminate of the present invention, at least an anti-glare layer and a low refractive index layer are formed in this order on a light-transmitting substrate. As a result, an uneven surface originating from the anti-glare layer is formed on the surface of the low refractive index layer, ensuring anti-glare performance. However, when the surface of the low refractive index layer is viewed in a microscopic field of view (5 μm square area), it is extremely flattened. Therefore, the first optical laminate of the present invention has excellent scratch resistance. The arithmetic mean roughness (Ra) of the surface of the low refractive index layer described above in the microscopic field of view is more preferably 3 nm or less, and even more preferably 2 nm or less. Furthermore, the ten-point average surface roughness (Rz) of the low refractive index layer in a microscopic field of view is more preferably 45 nm or less, and even more preferably 35 nm or less. The above-mentioned excellent scratch resistance refers to, for example, a friction load of 700g / cm² using Bonstar #0000 steel wool manufactured by Bonstar Sales Co., Ltd. 2 This means that no scratches will occur in a scratch resistance test involving 10 back-and-forth friction cycles. Here, the uneven surface shape of the low refractive index layer, particularly the flatness within a specific region on surfaces other than the protrusions, can be suitably formed by selecting the solvent for the low refractive index layer composition described later, drying and curing conditions when applying the low refractive index layer composition described later to form a coating film, and selecting the leveling agent contained in the anti-glare layer composition described later. In this specification, the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the surface of the low refractive index layer were measured and calculated using an AFM:SPM-9600 (manufactured by Shimadzu Corporation) under the following conditions. The definition of surface roughness parameters obtained by AFM is specified in JIS B0031 (1994), but in the case of AFM, it can be calculated as the average surface value within the scanning range (field of view) using the software included with the SPM-9600. Cantilever: NCH-W (Nano World) Scanning range: 5 μm (field of view: 5 μm x 5 μm) Scanning speed: 1Hz However, the above AFM measurements were taken excluding areas where specific defects such as detachment or unevenness were observed. The reason for setting the scanning range to 5 μm (field of view area 5 μm × 5 μm) is to minimize the influence of the unevenness of the anti-glare layer on the surface of the anti-glare layer, which originally has some kind of irregularity, in order to judge and control the texture and flatness of the surface of the low refractive index layer. If the field of view area is wider than the above range, it may become difficult to perform the measurement with AFM due to defects such as deflection of the measurement sample, unevenness of the anti-glare layer, and environmental foreign matter. On the other hand, if the field of view area is narrower than the above range, it may not be possible to properly evaluate the surface roughness of the low refractive index layer. Furthermore, the analysis conditions for Ra and Rz are as follows, and the instrument used for measurement was the SPM-9600 (manufactured by Shimadzu Corporation). <Preparation of measurement samples> Prepare the measurement samples in the following order (1) to (4). (1) Attach carbon tape to the sample stage and peel off the release paper with tweezers. (2) Hold the edge of the sample with tweezers and cut it with scissors. Cut it into 8mm x 8mm pieces, smaller than the carbon tape, to create the sample. (3) Remove any foreign matter by blowing on both sides of the sample with a blower. (4) Place the sample with the front (measurement surface) facing up, and attach carbon tape to the back of the sample to prepare the measurement sample. <Arithmetic mean roughness Ra> The arithmetic mean roughness Ra is the value obtained in micrometers (μm) by the following formula, when a reference length (l) is extracted from the surface roughness curve of a measured sample in the direction of the mean line, with the X-axis drawn in the direction of the mean line of this extracted portion and the Y-axis in the direction of the vertical scaling, and the roughness curve is represented as y=f(x).

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[0014] In the first optical laminate of the present invention, it is preferable that the hardness of the surface of the low refractive index layer, measured by nanoindentation at an indentation depth of 30 nm, is 440 MPa or higher. By having a hardness range like this, it is possible to suitably impart even better scratch resistance to the optical laminate of the first invention. Nanoindentation is a method that allows for the determination of hardness and elastic modulus using directly measurable physical quantities: load, displacement of the indenter from the point of contact with the sample surface, and time. Specifically, as shown in Figure 1(a), the indentation load p when an indenter (acute-angled indenter) is pressed into the sample, and the indentation depth h when the load is removed (indentation depth) are continuously observed in situ. From the indentation load-indentation depth curve shown in Figure 1(b), the hardness and elastic modulus can be determined without directly observing the indentation. However, since the fundamental principle of this method is derived under the assumption of an elastic deformation region, when determining hardness, it is calculated under elastic deformation conditions in accordance with this assumption. Since it is difficult to avoid the coexistence of elastic and plastic deformation during the indentation process, the surface at the point of plastic deformation is used as the starting point for the analysis in order to isolate only the contribution of elastic deformation. In other words, as shown in Figure 1(b), the hardness is determined by focusing on the unloading curve, which is a simple elastic recovery, in the indentation load-indentation depth curve. Therefore, the hardness of this nanoindentation method is the hardness that mainly reflects the elastic deformation properties of the cured resin layer made of polymer material such as the present invention. To improve scratch resistance, which is the objective of this invention, it is thought that the force that pushes back against the surface layer itself immediately after being subjected to some kind of abrasion force has an effect. Since this mechanism matches the hardness mechanism of the nanoindentation method described above (the force that elastically recovers after plastic deformation), among the various indentation hardness test methods, we selected the nanoindentation method as the most suitable for evaluation in this invention. By the way, as mentioned above, we believe that improving flatness and achieving a good surface texture on the low refractive index layer is essential for improving scratch resistance. When the surface texture is good, a load of 300 g / cm² is achieved. 2 ~500g / cm 2 It provides a certain degree of scratch resistance and is preferably used in fixed TV monitor displays for home use. On the other hand, recent displays are widely used in places like train stations and airports for digital signage, and are increasingly exposed to foreign matter such as dust, people, bags, and other items touching and rubbing against them, requiring a higher level of scratch resistance, for example, a load of 600g / cm². 2 In some cases, the above level of scratch resistance is desirable. In such cases, it has been found that improving the hardness of the low refractive index layer itself, which is the surface layer subjected to abrasion, along with flatness, is effective in improving its elastic deformation and elastic recovery. The reason for the indentation depth of 30 nm is to determine the hardness that involves the elastic deformation force of the low refractive index layer itself. Furthermore, this depth allows for stable measurements, and the influence of the underlying layer, such as an anti-glare layer, is minimal. The hardness of the surface of the low refractive index layer measured by the above nanoindentation method at an indentation depth of 30 nm is more preferably 500 MPa or higher, and even more preferably 600 MPa or higher. The preferred upper limit for the hardness of the surface of the low refractive index layer measured at the above indentation depth of 30 nm is 4000 MPa, the more preferred upper limit is 2000 MPa, and the even more preferred upper limit is 1600 MPa. If it exceeds 4000 MPa, microcracks are likely to occur due to the difference in hardness with the underlying anti-glare layer, etc., which can reduce the adhesion between the low refractive index layer and the anti-glare layer, etc., and may cause peeling. In this specification, the hardness measured by the nanoindentation method described above was obtained using the "TI950 TriboIndenter" manufactured by HYSITRON, Inc., in displacement control mode. Specifically, in the low refractive index layer described above, a Berkovich indenter (triangular pyramidal, made of diamond, 115-degree ridge angle) as shown in Figure 2 is pressed in for 30 nm at a loading rate of 10 nm / s, held for a certain period of time to relax residual stress, and then unloaded to obtain a load-displacement curve. Subsequently, the indentation hardness is automatically calculated by the device. Calculation overview: Using the unloading curve, the contact depth (the depth to which the sample contacts the indenter) is calculated, and the contact projected area (A(nm)) is calculated from that contact depth. 2 The area is determined, and using this area and the maximum load after relaxation (Pmax(μN)), the indentation stiffness is automatically calculated by Pmax / A. Note that the automatic calculation uses analytical methods such as those developed by Oliver-Pharr et al. To obtain stable measurement results, the sample surface was observed using a microscope at magnifications of 50 to 500x. Areas with extremely uneven structures were avoided, and measurements were taken on areas that were as flat as possible, free from any unusual defects. The indentation depth of the indenter was set to 30 nm, which allows for stable measurement of hardness by nanoindentation. The hardness measurement by nanoindentation was performed under conditions of 25°C ± 5°C and relative humidity between 30% and 70%.

[0015] For example, the following method can be used to prepare the measurement sample for the nanoindentation method described above. The optical laminate, cut to a size of 20 mm x 20 mm, is fixed to a commercially available microscope slide with the low refractive index layer facing upwards, using adhesive resin (product name "Aron Alpha (registered trademark) General Use," manufactured by Toagosei Co., Ltd.). Specifically, the adhesive resin is dropped onto the center of microscope slide 1 (product name "Slide Glass (Cut Type) 1-9645-11," manufactured by AS ONE Corporation). At this time, only one drop is dropped, without spreading the adhesive resin, and to prevent the adhesive resin from overflowing from the optical laminate when it is pressed open as described later. Subsequently, the optical laminate cut to the above size is brought into contact with the slide glass so that the low refractive index layer side is facing upwards and the adhesive resin is located in the center of the optical laminate. The adhesive resin is then spread between the slide glass 1 and the optical laminate to temporarily bond them together. Then, another new slide glass 2 is placed on top of the optical laminate to obtain a laminate of slide glass 1 / adhesive resin / optical laminate / slide glass 2. Next, place a weight of 30g to 50g on slide glass 2 and leave it at room temperature for 12 hours. After that, remove the weight and slide glass 2, and use this as the sample for measurement. Furthermore, the four corners of the optical laminate, which is fixed with adhesive resin, may be further secured with tape (product name "Sellotape®", manufactured by Nichiban Co., Ltd.).

[0016] For example, the following methods can be used to measure hardness (indentation hardness) using the nanoindentation method with the above-mentioned measurement samples. The above measurement sample is fixed to the measurement stage of the measuring instrument, which is installed parallel to the vibration isolation table. The method of securing the slide glass 1 is arbitrary; it can be done by fixing all four sides with tape (product name "Scotch Tape (registered trademark), manufactured by Nichiban Co., Ltd."), as long as the sample to be measured does not move. Furthermore, if the above measuring instrument has an air suction system, it may be fixed in place by the air suction system. After fixing the sample to the measurement stage, the indentation hardness at a position of 30 nm in indentation on the surface of the low refractive index layer is measured under the following measurement conditions. Indentation hardness is determined by measuring five arbitrary points near the center of the low refractive index layer surface of the sample (the region where the adhesive resin is present), and taking the arithmetic mean of the hardness of the five points obtained. However, any five points to be measured should be selected from areas that are as flat as possible, avoiding areas with extremely convex or extremely concave structures, by observing the low refractive index layer with a microscope at a magnification of 50x to 500x.

[0017] The specific measurement conditions for hardness when the above indenter is pressed in 30 nm are preferably as follows: Indenter used: Berkovich indenter (triangular pyramid) Measurement conditions: Displacement control method Displacement control mode Maximum displacement: 30nm Time to reach maximum displacement: 3 seconds Holding time at maximum displacement: 5 seconds Unloading time from maximum displacement: 3 seconds Test score: 5 points (This arithmetic mean will be the measurement result) Temperature at time of measurement: 25℃ Relative humidity at time of measurement: 50%

[0018] Furthermore, in the second optical laminate of the present invention, the low refractive index layer exhibits extremely excellent flatness. Specifically, when the arithmetic mean roughness Ra and the ten-point mean roughness Rz of the surface irregularities, as defined in JIS B0601 (1992), are measured in any 5 μm square region of the surface of the low refractive index layer, Ra is 1.5 nm or less, and Rz is 30 nm or less. In other words, in the second optical laminate of the present invention, at least an anti-glare layer and a low refractive index layer are formed in this order on a light-transmitting substrate. As a result, an uneven surface originating from the anti-glare layer is formed on the surface of the low refractive index layer, ensuring anti-glare performance. However, when the surface of the low refractive index layer is viewed in a microscopic field of view (5 μm square area), it is extremely flattened. In the second optical laminate of the present invention, the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) ranges are satisfied, and furthermore, the hardness measured by nanoindentation of the low refractive index layer surface satisfies a specific relationship, thereby providing the optical laminate with desirable flatness and excellent scratch resistance. In the second optical laminate of the present invention, the arithmetic mean roughness (Ra) of the surface of the low refractive index layer is preferably 1.2 nm or less, and more preferably 1.0 nm or less. Furthermore, in the second optical laminate of the present invention, the ten-point average roughness (Rz) of the surface of the low refractive index layer is preferably 25 nm or less, and more preferably 20 nm or less. The above-mentioned excellent scratch resistance refers to, for example, a friction load of 700g / cm² using Bonstar #0000 steel wool manufactured by Bonstar Sales Co., Ltd. 2 This means that no scratches will occur in a scratch resistance test involving 10 back-and-forth friction cycles. Here, the surface irregularities of the low refractive index layer in the optical laminate of the second present invention can be suitably formed by methods of control such as selecting the solvent for the low refractive index layer composition described later, drying and curing conditions when applying the low refractive index layer composition described later to form a coating film, and selecting the leveling agent contained in the anti-glare layer composition described later. In this specification, the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the surface of the low refractive index layer in the second optical laminate of the present invention were measured and calculated using an AFM:SPM-9600 (manufactured by Shimadzu Corporation) under the following conditions. The definition of surface roughness parameters obtained by AFM is specified in JIS B0031 (1994), but in the case of AFM, it can be calculated as the average surface value within the scanning range (field of view) using the software included with the SPM-9600. Cantilever: NCH-W (Nano World) Scanning range: 5 μm (field of view: 5 μm x 5 μm) Scanning speed: 1Hz However, the above AFM measurements were taken excluding areas where specific defects such as detachment or unevenness were observed. The reason for setting the scanning range to 5 μm (field of view area 5 μm × 5 μm) is to minimize the influence of the unevenness of the anti-glare layer on the surface of the anti-glare layer, which originally has some kind of irregularity, in order to judge and control the texture and flatness of the surface of the low refractive index layer. If the field of view area is wider than the above range, it may become difficult to perform the measurement with AFM due to defects such as deflection of the measurement sample, unevenness of the anti-glare layer, and environmental foreign matter. On the other hand, if the field of view area is narrower than the above range, it may not be possible to properly evaluate the surface roughness of the low refractive index layer. Furthermore, the analysis conditions for Ra and Rz are as follows, and the instrument used for measurement was the SPM-9600 (manufactured by Shimadzu Corporation). <Preparation of measurement samples> Prepare the measurement samples in the following order (1) to (4). (1) Attach carbon tape to the sample stage and peel off the release paper with tweezers. (2) Hold the edge of the sample with tweezers and cut it with scissors. Cut it into 8mm x 8mm pieces, smaller than the carbon tape, to create the sample. (3) Remove any foreign matter by blowing on both sides of the sample with a blower. (4) Place the sample with the front (measurement surface) facing up, and attach carbon tape to the back of the sample to prepare the measurement sample. <Arithmetic mean roughness Ra> The arithmetic mean roughness Ra is the value obtained in micrometers (μm) by the following formula, when a reference length (l) is extracted from the surface roughness curve of a measured sample in the direction of the mean line, with the X-axis drawn in the direction of the mean line of this extracted portion and the Y-axis in the direction of the vertical scaling, and the roughness curve is represented as y=f(x).

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[0019] In the second optical laminate of the present invention, the low refractive index layer is characterized in that the hardness when an indenter is pressed in by 300 nm using the nanoindentation method is higher than the hardness when an indenter is pressed in by 30 nm using the nanoindentation method. This hardness range allows for the second optical laminate of the present invention to be suitably imparted with excellent scratch resistance. Nanoindentation is a method that allows for the determination of hardness and elastic modulus using directly measurable physical quantities: load, displacement of the indenter from the point of contact with the sample surface, and time. Specifically, as shown in Figure 1(a), the indentation load p when an indenter (acute-angled indenter) is pressed into the sample, and the indentation depth h when the load is removed (indentation depth) are continuously observed in situ. From the indentation load-indentation depth curve shown in Figure 1(b), the hardness and elastic modulus can be determined without directly observing the indentation. However, since the fundamental principle of this method is derived under the assumption of an elastic deformation region, when determining hardness, it is calculated under elastic deformation conditions in accordance with this assumption. Since it is difficult to avoid the coexistence of elastic and plastic deformation during the indentation process, the surface at the point of plastic deformation is used as the starting point for the analysis in order to isolate only the contribution of elastic deformation. In other words, as shown in Figure 1(b), the hardness is determined by focusing on the unloading curve, which is a simple elastic recovery, in the indentation load-indentation depth curve. Therefore, the hardness of this nanoindentation method is the hardness that mainly reflects the elastic deformation properties of the cured resin layer made of polymer material such as the present invention. To improve scratch resistance, which is the objective of this invention, it is thought that the force that pushes back against the surface layer itself immediately after being subjected to some kind of abrasion force has an effect. Since this mechanism matches the hardness mechanism of the nanoindentation method described above (the force that elastically recovers after plastic deformation), among the various indentation hardness test methods, we selected the nanoindentation method as the most suitable for evaluation in this invention. By the way, as mentioned above, we believe that improving flatness and achieving a good surface texture on the low refractive index layer is essential for improving scratch resistance. By achieving extreme flatness, a good surface texture, and the aforementioned balanced hardness (nanoindentation hardness), a load of 700 g / cm² can be achieved. 2 This provides the above-mentioned excellent abrasion resistance. The hardness measured when an indenter is pressed in 30 nm is the hardness that involves only the elastic deformation and elastic recovery properties of the low refractive index layer. On the other hand, the hardness measured when an indenter is pressed in 300 nm is measured at a depth 200 nm deeper than the low refractive index layer, which is approximately 100 nm thick. For example, if the substrate of the low refractive index layer is an anti-glare layer, the hardness that involves the properties of both the anti-glare layer and the low refractive index layer is considered. While abrasion resistance is primarily related to the low refractive index layer, as the load increases, the underlying anti-glare layer also becomes more relevant. In this context, the underlying layer is not limited to a single layer directly beneath the low refractive index layer, but may refer to the entirety of multiple layers below the low refractive index layer. The combination of flatness and hardness (nanomindentation hardness) described above is effective in achieving high scratch resistance for the following reasons. When the hardness of the base layer / low refractive index layer, such as an anti-glare layer / low refractive index layer, is greater than the hardness of the low refractive index layer, the resulting state of elastic properties in the laminate is such that it can resist abrasion and exhibit elastic recovery force. If the surface is extremely flat, it can resist abrasion even better and continue to slide, thus maintaining its original, scratch-free state. On the other hand, if the hardness of the low refractive index layer is greater than the hardness of the base layer / low refractive index layer, the force that resists abrasion weakens, making it difficult to achieve the above state. Furthermore, the excessively high hardness of the low refractive index layer can easily cause cracks and weaken adhesion to the base layer. In the second optical laminate of the present invention, the hardness measured by the nanoindentation method above, when an indenter is pressed in by 300 nm, has a preferred lower limit of 490 MPa, a preferred upper limit of 580 MPa, a more preferred lower limit of 510 MPa, and a more preferred upper limit of 560 MPa. Furthermore, in the second optical laminate of the present invention, the preferred lower limit of the hardness when the indenter is pressed in by 30 nm using the nanoindentation method described above is 470 MPa, the preferred upper limit is 560 MPa, the more preferred lower limit is 490 MPa, and the more preferred upper limit is 540 MPa. In this specification, the hardness measured by the nanoindentation method described above was obtained using the "TI950 TriboIndenter" manufactured by HYSITRON, Inc., in displacement control mode. Specifically, in the low refractive index layer described above, a Berkovich indenter (triangular pyramidal, made of diamond, 115-degree ridge angle) as shown in Figure 2 is pressed in at a loading rate of 10 nm / s for 30 nm or 300 nm, held for a certain period of time to relax residual stress, and then unloaded to obtain a load-displacement curve. Subsequently, the indentation hardness is automatically calculated by the device. Calculation overview: Using the unloading curve, the contact depth (the depth to which the sample contacts the indenter) is calculated, and the contact projected area (A(nm)) is calculated from that contact depth. 2The area is determined, and using this area and the maximum load after relaxation (Pmax(μN)), the indentation stiffness is automatically calculated by Pmax / A. Note that the automatic calculation uses analytical methods such as those developed by Oliver-Pharr et al. To obtain stable measurement results, the sample surface was observed using a microscope at a magnification of 50 to 500x. Areas with extremely uneven structures were avoided, and measurements were taken on areas that were as flat as possible, free from any unusual defects. The indentation depth of the indenter was selected to be 30 nm or 300 nm, which allows for stable measurement of hardness by nanoindentation. The hardness measurement by nanoindentation was performed in an environment of 25°C ± 5°C and a relative humidity of 30% to 70%.

[0020] For example, the following method can be used to prepare the measurement sample for the nanoindentation method described above. The optical laminate, cut to a size of 20 mm x 20 mm, is fixed to a commercially available microscope slide with the low refractive index layer facing upwards, using adhesive resin (product name "Aron Alpha (registered trademark) General Use," manufactured by Toagosei Co., Ltd.). Specifically, the adhesive resin is dropped onto the center of microscope slide 1 (product name "Slide Glass (Cut Type) 1-9645-11," manufactured by AS ONE Corporation). At this time, only one drop is dropped, without spreading the adhesive resin, and to prevent the adhesive resin from overflowing from the optical laminate when it is pressed open as described later. Subsequently, the optical laminate cut to the above size is brought into contact with the slide glass so that the low refractive index layer side is facing upwards and the adhesive resin is located in the center of the optical laminate. The adhesive resin is then spread between the slide glass 1 and the optical laminate to temporarily bond them together. Then, another new slide glass 2 is placed on top of the optical laminate to obtain a laminate of slide glass 1 / adhesive resin / optical laminate / slide glass 2. Next, place a weight of 30g to 50g on slide glass 2 and leave it at room temperature for 12 hours. After that, remove the weight and slide glass 2, and use this as the sample for measurement. Furthermore, the four corners of the optical laminate, which is fixed with adhesive resin, may be further secured with tape (product name "Sellotape®", manufactured by Nichiban Co., Ltd.).

[0021] For example, the following methods can be used to measure hardness (indentation hardness) using the nanoindentation method with the above-mentioned measurement samples. The above measurement sample is fixed to the measurement stage of the measuring instrument, which is installed parallel to the vibration isolation table. The method of securing the slide glass 1 is arbitrary; it can be done by fixing all four sides with tape (product name "Scotch Tape (registered trademark), manufactured by Nichiban Co., Ltd."), as long as the sample to be measured does not move. Furthermore, if the above measuring instrument has an air suction system, it may be fixed in place by the air suction system. After fixing the sample to the measurement stage, the indentation hardness at a depth of 30 nm or 300 nm on the surface of the low refractive index layer is measured under the following measurement conditions. Indentation hardness is determined by measuring five arbitrary points near the center of the low refractive index layer surface of the sample (the region where the adhesive resin is present), and taking the arithmetic mean of the hardness of the five points obtained. However, any five points to be measured should be selected from areas that are as flat as possible, avoiding areas with extremely convex or extremely concave structures, by observing the low refractive index layer with a microscope at a magnification of 50x to 500x.

[0022] The specific measurement conditions for hardness when the above indenter is pressed in 30 nm are preferably as follows: Indenter used: Berkovich indenter (triangular pyramidal, diamond, 115-degree ridge angle) Measurement conditions: Displacement control method Displacement control mode Maximum displacement: 30nm Time to reach maximum displacement: 3 seconds Holding time at maximum displacement: 5 seconds Unloading time from maximum displacement: 3 seconds Test score: 5 points (This arithmetic mean will be the measurement result) Temperature at time of measurement: 25℃ Relative humidity at time of measurement: 50% The specific measurement conditions for hardness when the above indenter is pressed in 300 nm are preferably as follows: Indenter used: Berkovich indenter (triangular pyramid) Measurement conditions: Displacement control method Displacement control mode. Maximum displacement: 300 nm Time to reach maximum displacement: 30 seconds Holding time at maximum displacement: 5 seconds Unloading time at maximum displacement: 30 seconds Test score: 5 points (This arithmetic mean will be the measurement result) Temperature at time of measurement: 25℃ Relative humidity at time of measurement: 50%

[0023] In the second optical laminate of the present invention, it is preferable that the contact angle of the surface of the low refractive index layer with respect to water is 102° or less. When the contact angle of the surface of the low refractive index layer with respect to water is 102° or less, sufficient interlayer adhesion between the low refractive index layer and the other layers can be provided, and scratch resistance can be improved. The contact angle of the surface of the low refractive index layer with respect to water is more preferably 100° or less.

[0024] The low refractive index layer described above preferably contains hollow silica fine particles. The hollow silica nanoparticles described above play a role in lowering the refractive index of the low refractive index layer while maintaining its layer strength. In this specification, "hollow silica nanoparticles" refers to silica nanoparticles with a structure in which gas is filled inside, and whose refractive index decreases inversely proportional to the gas occupancy rate compared to the original refractive index of the silica nanoparticles.

[0025] The specific examples of the hollow silica fine particles described above are not particularly limited, but for example, silica fine particles prepared using the technology disclosed in Japanese Patent Application Publication No. 2001-233611 are preferred. Because hollow silica fine particles are easy to manufacture and have high hardness, when mixed with binder components, etc., described later to form a low refractive index layer, the strength of the layer is improved and it is possible to adjust the refractive index to be low.

[0026] In the optical laminate of the present invention, the hollow silica nanoparticles have an average particle diameter of 45 to 65 nm. If the particle diameter is less than 45 nm, the low refractive index layer cannot be sufficiently reduced in refractive index. On the other hand, if the particle diameter exceeds 65 nm, the amount of particle protrusion from the surface of the low refractive index layer increases, making it impossible to obtain the extremely smooth low refractive index layer described above. The preferred lower limit for the average particle diameter of the hollow silica nanoparticles is 47 nm, and the preferred upper limit is 60 nm. Within this range, the smoothness of the low refractive index layer can be maintained, and a good appearance can be obtained. The average particle diameter of the hollow silica microparticles mentioned above refers to the average particle diameter of the hollow silica microparticles in the low refractive index layer. This value is calculated by observing the cross-section in the thickness direction of the low refractive index layer using SEM, TEM, and STEM, selecting 30 arbitrary single-particle hollow silica microparticles, measuring the particle diameter of their cross-sections, and averaging these values. For example, using a scanning transmission electron microscope (STEM) (product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation), the signal selection is set to "TE", the acceleration voltage to "30kV", the emission current to "10μA", the probe current to "Norm", the focus mode to "UHR", the condenser lens 1 to "5.0", the WD to "8mm", and the tilt to "0°", 20 images are taken of any point in the thickness direction of the low refractive index layer at magnifications of 10,000x to 200,000x. Then, the maximum diameter of 30 hollow silica nanoparticles is measured on the image screen using the software included with the STEM, and the arithmetic mean value is obtained.

[0027] In the optical laminate of the present invention, the average particle diameter of the hollow silica fine particles is preferably 50% or more and less than 100% of the thickness of the low refractive index layer. If it is less than 50%, the refractive index of the low refractive index layer cannot be sufficiently lowered, and the anti-reflective performance of the optical laminate of the present invention may be poor. On the other hand, if it is 100% or more, fine irregularities caused by the hollow silica fine particles are formed on the surface of the low refractive index layer, resulting in insufficient control of the texture, and it may not be possible to create a low refractive index layer with sufficient flatness in a certain area, and the haze of the optical laminate of the present invention may worsen. The preferred lower limit for the average particle diameter of the hollow silica fine particles is 70% and the preferred upper limit is 80% of the thickness of the low refractive index layer. By having the average particle diameter of the hollow silica fine particles within this range, the effects of the present invention can be more favorably achieved.

[0028] Furthermore, the hollow silica nanoparticles described above preferably have a shell thickness of 5 to 12 nm. If it is less than 5 nm, the strength of the hollow silica nanoparticles may be insufficient, and if it exceeds 12 nm, the low refractive index layer may not be sufficiently reduced in refractive index. A more preferable lower limit for the shell thickness is 6 nm, and a more preferable upper limit is 10 nm. The shell refers to the outer shell composed of silica excluding the gas present in the central part of the hollow silica nanoparticles, and the thickness of the shell can be measured by cross-sectional microscopic observation of the low refractive index layer.

[0029] The content of the hollow silica fine particles in the low refractive index layer is adjusted as appropriate depending on the content of the hollow silica fine particles in the low refractive index layer described later, but it is preferably 50 to 200 parts by mass per 100 parts by mass of the binder resin (solid content) described later. If it is less than 50 parts by mass, the content of hollow silica fine particles is small, so the refractive index of the low refractive index layer does not become sufficiently low, and the anti-reflective performance of the optical laminate of the present invention may be insufficient. On the other hand, if it exceeds 200 parts by mass, the effect of adding hollow silica fine particles is not seen, and the strength of the low refractive index layer may be insufficient. A more preferable lower limit is 60 parts by mass, and a more preferable upper limit is 180 parts by mass.

[0030] The low refractive index layer described above preferably contains solid silica fine particles. In this specification, "solid silica nanoparticles" refers to silica nanoparticles that, unlike the hollow silica nanoparticles described above, have a structure in which gas is not filled inside and possess the refractive index inherent to silica nanoparticles. The solid silica nanoparticles may be amorphous wet silica synthesized in a liquid, or dry silica mainly produced by the combustion of silicon tetrachloride.

[0031] The solid silica fine particles described above preferably have an average particle diameter of 8 to 50 nm. If the particle diameter is less than 8 nm, the hardness of the surface of the low refractive index layer may not increase, and if it exceeds 50 nm, the arithmetic mean roughness Ra and Rz measured in any 5 μm square region of the surface of the low refractive index layer may increase. The more preferable lower limit for the average particle size of the solid silica nanoparticles described above is 10 nm, and the more preferable upper limit is 20 nm. Here, the average particle size of the solid silica fine particles refers to the value measured in the same manner as the hollow silica fine particles described above.

[0032] The content of the solid silica fine particles in the low refractive index layer is preferably 10 to 100 parts by mass per 100 parts by mass of the solid content of the binder resin, which will be described later. If the content of the solid silica fine particles in the low refractive index layer is less than 10 parts by mass, the effect of increasing the hardness of the surface of the low refractive index layer may be insufficient, and sufficient scratch resistance may not be provided. If it exceeds 100 parts by mass, it may become difficult to adjust the low reflectivity, and it may not be possible to create a low refractive index layer with sufficient flatness. A more preferable lower limit for the content of the solid silica fine particles in the low refractive index layer is 20 parts by mass, a more preferable upper limit is 90 parts by mass, an even more preferable upper limit is 80 parts by mass, and a particularly preferable upper limit is 60 parts by mass.

[0033] Furthermore, it is preferable that the solid silica fine particles have a functional group on their surface that is reactive to the binder resin described later, such as a functional group having an ethylenically unsaturated bond. Having such a reactive functional group on the surface results in excellent hardness of the low refractive index layer.

[0034] In the optical laminate of the present invention, the low refractive index layer may contain additives within a range that does not impede the hardness described above. The above-mentioned additives are not particularly limited and include, for example, fluorine-based compounds, silicone-based compounds, and silicone-fluorine atom-containing compounds. These additives may be used individually or in combination of two or more. For example, a material with good compatibility with the additive contained in the substrate layer on which the low refractive index layer is laminated may be appropriately selected and combined from the above-mentioned compounds. By incorporating the above-mentioned fluorine-based compounds, silicone-based compounds, and silicone-fluorine atom-containing compounds into the low refractive index layer, even if the surface has an extremely smooth low refractive index layer in a specific range of areas other than the convex portions as described above, the optical laminate of the present invention has excellent anti-glare properties and uneven surface (especially the convex portions), resulting in excellent blocking resistance. In the optical laminate of the present invention, it is presumed that the above-mentioned compounds are present in high concentrations on the surface and air interface side of the low refractive index layer. Therefore, the above-mentioned additives also function as antifouling agents. For this reason, the optical laminate of the present invention also possesses excellent antifouling performance.

[0035] The above-mentioned silicone-based compound is not particularly limited, and examples include organosilicone. While the organosilicon is not particularly limited, it is preferable that it has a reactive functional group in its molecule. Having the above-mentioned reactive functional group allows the organosilicon to react with the binder component described later, effectively preventing it from falling out of the low refractive index layer. Examples of organosilicones having the above-mentioned reactive functional groups include (poly)dimethylsiloxane, (poly)diethylsiloxane, (poly)diphenylsiloxane, (poly)methylphenylsiloxane, alkyl-modified (poly)dimethylsiloxane, azo group-containing (poly)dimethylsiloxane, dimethyl silicone, phenylmethyl silicone, alkyl / aralkyl-modified silicone, fluorosilicone, polyether-modified silicone, fatty acid ester-modified silicone, methyl hydrogen silicone, silanol group-containing silicone, alkoxy group-containing silicone, phenol group-containing silicone, (meth)acrylic-modified silicone, amino-modified silicone, carboxylic acid-modified silicone, carbinol-modified silicone, epoxy-modified silicone, mercapto-modified silicone, fluorine-modified silicone, and polyether-modified silicone. Among these, those having a dimethylsiloxane structure are preferred because they are less prone to the problem of bleed-out from the low refractive index layer.

[0036] The content of the above-mentioned organic silicone is appropriately determined based on the desired blocking resistance and antifouling properties of the low refractive index layer, but it is preferably 1 to 10 parts by mass per 100 parts by mass of the total of the hollow silica fine particles and the binder component described later. If it is less than 1 part by mass, it may not be possible to impart sufficient blocking resistance and antifouling properties to the formed low refractive index layer, and if it exceeds 10 parts by mass, the added organic silicone may bleed out from the low refractive index layer. Furthermore, the effect of adding the organic silicone may not be observed, manufacturing costs may increase, the hardness and appearance of the resulting low refractive index layer may decrease, and it may even cause an increase in reflectivity. A more preferable lower limit for the content of the above-mentioned organic silicone is 2 parts by mass, and a more preferable upper limit is 8 parts by mass.

[0037] Examples of the fluorine-based compounds that also function as antifouling agents include compounds containing a reactive functional group and a fluorine atom, and examples of the silicone-fluorine atom-containing compounds include compounds containing a reactive functional group, a fluorine atom and a silicon atom. By including such antifouling agents, the antifouling performance of the formed low refractive index layer can be further improved.

[0038] Compounds containing the above-mentioned reactive functional group and fluorine atom can be broadly used, for example, reactive fluorine compounds, particularly fluorine-containing monomers having an ethylenically unsaturated bond. More specifically, examples include fluoroolefins (e.g., fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluorobutadiene, perfluoro-2,2-dimethyl-1,3-dioxol, etc.). Other examples include (meth)acrylate compounds having a fluorine atom in the molecule, such as 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate, 2-(perfluorobutyl)ethyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 2-(perfluorooctyl)ethyl (meth)acrylate, 2-(perfluorodecyl)ethyl (meth)acrylate, and methyl α-trifluoro(meth)acrylate; and fluorine-containing polyfunctional (meth)acrylate ester compounds having a fluoroalkyl group, fluorocycloalkyl group, or fluoroalkylene group with 1 to 14 carbon atoms and at least 3 fluorine atoms in the molecule, and at least 2 (meth)acryloyloxy groups. Furthermore, examples include fluoropolymers and oligomers having fluorinated alkylene groups in the main chain, and fluorinated polymers and oligomers having fluorinated alkylene groups and fluorinated alkyl groups in the main chain and side chains. Among these, fluorinated polymers having fluorinated alkylene groups and fluorinated alkyl groups in the main chain and side chains are particularly preferred because they are less prone to the problem of bleed-out from the low refractive index layer.

[0039] Examples of compounds containing the above-mentioned reactive functional group, a fluorine atom, and a silicon atom include silicone-containing vinylidene fluoride copolymers obtained by reacting the above-mentioned reactive fluorine compound with an organosilicon having the above-mentioned reactive functional group in its molecule, or fluorine-modified organosilicon compounds.

[0040] In the optical laminate of the present invention, the low refractive index layer may contain an antifouling agent in addition to the fluorine-based compound, silicone-based compound, and silicone-fluorine atom-containing compound, as long as it does not hinder the effects of the present invention described above. By further containing an antifouling agent in the low refractive index layer, the optical laminate of the present invention will have even better antifouling performance.

[0041] Furthermore, it is preferable that the low refractive index layer contains a binder component. Examples of the binder components mentioned above include ionizing radiation-curable resins, and in the present invention, (meth)acrylic resin is particularly preferred. In this specification, "(meth)acrylic" means acrylic or methacrylic. Examples of the (meth)acrylic resin mentioned above include polymers or copolymers of (meth)acrylic monomers. The (meth)acrylic monomer is not particularly limited, but polyfunctional acrylates such as pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, pentaerythritol (meth)tetraacrylate, dipentaerythritol penta(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and isocyanuric acid EO-modified tri(meth)acrylate are preferred. Furthermore, these (meth)acrylate monomers may also have a modified molecular skeleton, and those modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, etc., can also be used. These (meth)acrylic monomers may be used individually or in combination of two or more. These (meth)acrylic monomers satisfy the refractive index range described later, exhibit excellent curing reactivity, and can improve the hardness of the resulting low refractive index layer.

[0042] The above (meth)acrylic monomer preferably has a refractive index of 1.47 to 1.53. It is practically impossible to have a refractive index below 1.47, and if it exceeds 1.53, it may not be possible to obtain a low refractive index layer with a sufficiently low refractive index.

[0043] Furthermore, the (meth)acrylic monomer described above preferably has a weight-average molecular weight of 250 to 1000. If it is less than 250, the number of functional groups will be small, which may reduce the hardness of the resulting low refractive index layer. If it exceeds 1000, the functional group equivalent (number of functional groups / molecular weight) will generally be small, which may result in a low crosslinking density and prevent the acquisition of a low refractive index layer with sufficient hardness. The weight-average molecular weight of the (meth)acrylic monomer can be determined by converting it to polystyrene equivalent using gel permeation chromatography (GPC). Tetrahydrofuran or chloroform can be used as the solvent for the GPC mobile phase. For the measurement column, it is preferable to use a combination of commercially available columns for tetrahydrofuran or chloroform. Examples of such commercially available columns include Shodex GPC KF-801 and GPC-KF800D (both trade names, manufactured by Showa Denko Corporation). For the detector, it is preferable to use an RI (differential refractive index) detector and a UV detector. Using such a solvent, column, and detector, the weight-average molecular weight can be appropriately measured using a GPC system such as Shodex GPC-101 (manufactured by Showa Denko Corporation).

[0044] In the optical laminate of the present invention, it is preferable that the change rate of the contact angle of water on the surface of the low refractive index layer before and after the saponification treatment is 15% or less. If it exceeds 15%, the organosilicon on the surface of the low refractive index layer may peel off, and the blocking resistance and stain resistance of the optical laminate of the present invention may become insufficient. A more preferable upper limit of the change rate of the contact angle of water on the surface of the low refractive index layer is 10%, and a further preferable upper limit is 5%. The change rate of the contact angle of water on the surface of the low refractive index layer before and after the saponification treatment can be calculated by {(pre-measured value - post-measured value) / pre-measured value}×100, which is measured with a contact angle meter before and after the saponification treatment of the low refractive index layer.

[0045] In the optical laminate of the present invention, it is preferable that the refractive index of the low refractive index layer is less than 1.45. If it is 1.45 or more, the antireflection performance of the optical laminate of the present invention may become insufficient. A more preferable lower limit is 1.15, and a preferable lower limit for improving physical strength is 1.20. For good display quality, a preferable upper limit of the refractive index of the low refractive index layer is 1.40, and a particularly preferable upper limit for meeting the high-level display quality of recent image display devices is 1.36.

[0046] The film thickness (nm) d of the low refractive index layer A is represented by the following formula (I): d A =mλ / (4n A )(I) (In the above formula, n A represents the refractive index of the low refractive index layer, m represents a positive odd number, preferably 1, λ is the wavelength, preferably a value in the range of 480 to 580 nm) is preferably satisfied. <00​​​​​​​​​​​​

[0048] The low refractive index layer described above can be formed by preparing a low refractive index layer composition containing the hollow silica fine particles, solid silica fine particles, monomer components of the binder component, and fluorine-based compounds, silicone-based compounds, and silicone-fluorine atom-containing compounds, as well as other antifouling agents as needed, and using the low refractive index layer composition.

[0049] The above-mentioned low refractive index layer composition may further contain a solvent. The above solvents are not particularly limited and include, for example, alcohols such as methanol, ethanol, propanol, isopropyl alcohol, n-butanol, s-butanol, t-butanol, benzyl alcohol, and PGME; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, heptanone, diisobutyl ketone, and diethyl ketone; esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate, and PGMEA; aliphatic hydrocarbons such as hexane and cyclohexane; halogenated hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride; aromatic hydrocarbons such as benzene, toluene, and xylene; amides such as dimethylformamide, dimethylacetamide, and n-methylpyrrolidone; ethers such as diethyl ether, dioxane, and tetrahydrofuran; and ether alcohols such as 1-methoxy-2-propanol. Among these, methyl isobutyl ketone, methyl ethyl ketone, isopropyl alcohol (IPA), n-butanol, s-butanol, t-butanol, PGME, and PGMEA are preferred.

[0050] Furthermore, the above-mentioned low refractive index layer composition may contain other components as needed. Other components mentioned above include, for example, photopolymerization initiators, leveling agents, crosslinking agents, curing agents, polymerization accelerators, viscosity modifiers, antistatic agents, ultraviolet absorbers, light absorption wavelength modifiers, pigments, dyes, and resins other than those mentioned above.

[0051] Examples of the above-mentioned photopolymerization initiators include acetophenones (for example, 1-hydroxycyclohexylphenyl ketone, commercially available under the trade name Irgacure 184 (manufactured by BASF)), benzophenones, thioxanthones, benzoin, benzoin methyl ether, etc., when the above-mentioned low refractive index layer composition contains a resin system having a radically polymerizable unsaturated group. These may be used alone or in combination of two or more. Furthermore, if the low refractive index layer composition contains a resin system having a cationic polymerizable functional group, examples of the photopolymerization initiator include aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene compounds, benzoin sulfonic acid esters, etc., which may be used alone or in combination of two or more. Specific photopolymerization initiators that can be used in the present invention include, for example, Irgacure 184, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 819, Irgacure 127, Irgacure 500, Irgacure 754, Irgacure 250, Irgacure 1800, Irgacure 1870, Irgacure OXE01, Irgacure OXE02, DAROCUR TPO, DAROCUR 1173 from Ciba Specialty Chemicals; Speedcure MBB, Speedcure PBZ, Speedcure ITX, Speedcure CTX, Speedcure EDB, Esacure ONE, Esacure KIP150, Esacure KTO46 from Nippon Sieber Hegner Co., Ltd.; and KAYACURE DETX-S, KAYACURE from Nippon Kayaku Co., Ltd. Examples include CTX, KAYACURE BMS, and KAYACURE DMBI. Among these, Irgacure 369, Irgacure 127, Irgacure 907, Esacure ONE, Speedcure MBB, Speedcure PBZ, and KAYACURE DETX-S are preferred. The amount of the above-mentioned photopolymerization initiator added is preferably 0.1 to 10 parts by mass per 100 parts by mass of the solid content of the above-mentioned binder resin. The leveling agent, crosslinking agent, curing agent, polymerization accelerator, viscosity modifier, antistatic agent, ultraviolet absorber, light absorption wavelength modifier, pigment, dye, and other resins mentioned above may be those of known origin.

[0052] Furthermore, it is preferable that the viscosity of the above-mentioned low refractive index layer composition be in the range of 0.5 to 5 cps (25°C), preferably 0.7 to 3 cps (25°C), to obtain desirable coatability. This makes it possible to realize an anti-reflective film with excellent visible light reflection, to form a uniform thin film without uneven coating, and to form a low refractive index layer with particularly excellent adhesion to the object to be coated.

[0053] The method for preparing the above-mentioned low refractive index layer composition is not particularly limited, and can be obtained, for example, by mixing the hollow silica fine particles, the monomer component of the binder component, the organic silicone, and components such as an antifouling agent, solvent, and photopolymerization initiator, which may be added as needed. Mixing can be carried out using known equipment such as a paint shaker, bead mill, kneader, or mixer. Known methods such as those mentioned above can be used.

[0054] The low refractive index layer described above can be formed by applying the low refractive index layer composition described above onto the anti-glare layer described later, drying the resulting coating film as needed, and curing the coating film by irradiation with ionizing radiation and / or heating. The method for applying the above-mentioned low refractive index layer composition is not particularly limited and includes various methods such as spin coating, dip coating, spray coating, dye coating, bar coating, roll coating, meniscus coating, flexographic printing, screen printing, and speed coating.

[0055] The above light-transmitting substrate is preferably smooth, heat-resistant, and has excellent mechanical strength. Specific examples of materials for forming the light-transmitting substrate include, for example, acrylic resins such as polyester (polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyetherketone, and polymethyl methacrylate (PMMA), as well as polycarbonate or thermoplastic resins such as polyurethane. Preferably, polyester (polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, and polymethyl methacrylate (PMMA) are used. The resin materials constituting the above light-transmitting substrate may be used individually or in combination of multiple materials.

[0056] The above light-transmitting substrate is preferably made of the above thermoplastic resin in the form of a highly flexible film, but depending on the application where curability is required, it is also possible to use plates of these thermoplastic resins, or to use plates such as glass plates.

[0057] Other examples of light-transmitting substrates include amorphous olefin polymer (Cyclo-Olefin-Polymer:COP) films having an alicyclic structure. These substrates utilize norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, etc. Examples include Zeonex and Zeonor (COP) from Nippon Zeon Co., Ltd., Sumilight FS-1700 from Sumitomo Bakelite Co., Ltd., Arton (modified norbornene resin) from JSR Corporation, Appel (cyclic olefin copolymer) from Mitsui Chemicals, Inc., Topas (cyclic olefin copolymer) from Ticona, Inc., and Optrets OZ-1000 series (alicyclic acrylic resin) from Hitachi Chemical Co., Ltd. Furthermore, the FV series (low birefringence, low photomodulus film) manufactured by Asahi Kasei Chemicals Corporation is also preferred as an alternative substrate to triacetylcellulose.

[0058] The thickness of the above light-transmitting substrate is preferably 5 to 300 μm in the case of a film, more preferably with a lower limit of 10 μm, even more preferably with a lower limit of 15 μm, and more preferably with an upper limit of 200 μm. If thinning is desired, the upper limit is even more preferably 90 μm, particularly preferably 70 μm, and most preferably 50 μm. If the above light-transmitting substrate is in the case of a plate, the thickness may exceed these thicknesses. When forming the anti-glare layer or the like on the light-transmitting substrate, the above-mentioned substrate may be subjected to physical or chemical treatments such as corona discharge treatment or oxidation treatment, as well as the application of a coating called an anchoring agent or primer in order to improve adhesion. Furthermore, for light-transmitting substrates for LCDs, triacetylcellulose or polymethyl methacrylate, polyester, norbornene-based resins, and cyclic olefin-based resins are commonly used as materials. For light-transmitting substrates for OLEDs, in addition to the light-transmitting substrates for LCDs mentioned above, polyimide film (which may be a mixture of polyimide and polyamide) is also used as a material. When aiming for thin-film display, the thickness of the light-transmitting substrate is preferably 7 to 45 μm. When aiming for even thinner display, a more preferable upper limit for the thickness of the light-transmitting substrate is 30 μm, and for materials that can be further thinned using resin systems (such as COP and polyimide film), the preferable upper limit is 20 μm.

[0059] The anti-glare layer described above is formed on one surface of the light-transmitting substrate and has an uneven surface. The method for forming the uneven surface of the anti-glare layer is not particularly limited, and may be, for example, formed by a composition containing an anti-glare agent, by phase separation of a binder resin, or by embossing. In particular, it is preferable that the uneven shape of the anti-glare layer is formed by an anti-glare layer composition containing an anti-glare agent and a binder resin.

[0060] The above-mentioned anti-glare agent is in the form of fine particles, and its shape is not particularly limited, such as spherical, elliptical, or irregular. Furthermore, organic fine particles, inorganic fine particles, or inorganic components can be used as the above-mentioned anti-glare agent, and transparent fine particles are preferred. The material of the above-mentioned organic fine particles is not particularly limited, and examples include polystyrene resin, melamine resin, acrylic resin, styrene-acrylic copolymer, benzoguanamine-formaldehyde condensate, melamine-formaldehyde condensate, polycarbonate resin, polyethylene resin, urethane resin, epoxy resin, silicone resin, polyvinylidene fluoride resin, and polyfluoroethylene resin. Organic fine particles are preferred as a basic material for creating a convex base, particularly one with relatively large convex shapes. The materials for the inorganic fine particles mentioned above are not particularly limited, and examples include silica, alkali metal oxides, alkaline earth oxides, titanium oxide, zinc oxide, aluminum oxide, boron oxide, tin oxide, phosphorus oxide, indium tin oxide, zirconium oxide, other metal oxides, metals, metal nitrides, carbon isotopes, fine silicic acid, calcium silicate, aluminum silicate, calcium carbonate, magnesium carbonate, fine talc, titanium oxide, diatomaceous earth, smectite, kaolin clay, and the like. The inorganic components mentioned above are not particularly limited, and examples include silica sol, metal oxide sols such as zirconia sol, aerosil, and clay-based components such as swelling clay. The inorganic fine particles and inorganic components described above can be aggregated individually and used as a base for uneven surfaces, particularly convex shapes. Furthermore, when an uneven base is created using organic fine particles, it is preferable to have inorganic fine particles and inorganic components present around the organic fine particles, or to have aggregates of inorganic fine particles and inorganic components present between organic fine particles (where the organic fine particles are not aggregated and the distance between them is at least three times the average particle size of the organic fine particles) as a material for forming a flat shape within a specific area in order to improve scratch resistance. The above-mentioned anti-glare agents may be used individually or in combination of two or more types. The aggregation of microparticles in this invention includes not only aggregates of microparticles that are in close contact with each other at some point within a 360° radius around a given particle, but also aggregates of microparticles that are clustered together at a distance of less than three times the average particle size at some point within a 360° radius around a given particle. In particular, since a binder resin is present around the microparticles in the anti-glare layer, it is considered that aggregates are more likely to form with the binder between the microparticles than aggregates where the microparticles are completely in contact with each other.

[0061] The inorganic fine particles mentioned above may also be conductive metal oxide fine particles. The conductive metal oxide fine particles are not particularly limited and include, for example, ZnO, Sb2O2, SnO2, CeO2, indium tin oxide, In2O3, Al2O3, antimond-doped tin oxide, aluminum-doped zinc oxide, and the like. Furthermore, the above organic fine particles, the above inorganic fine particles, and the above inorganic component materials may be used simultaneously, or multiple quantities of each may be used.

[0062] The above organic or inorganic fine particles / inorganic components may have a core / shell structure. In this case, the shell portion may have polymerizable functional groups introduced on its surface. The shell portion may have a structure in which polymerizable functional groups are directly attached to the core by chemical reaction, either directly or as grafts of monomers, oligomers, or polymers containing polymerizable functional groups; or a structure in which monomers, oligomers, or polymers having polymerizable functional groups are attached to the surface of the particle portion (core) by chemical reaction in the form of a coating.

[0063] In order to suitably control the shape within a specific region when the low refractive index layer is laminated on the anti-glare layer, it is important to suitably control the surface irregularities of the anti-glare layer. A preferred example is an anti-glare layer that contains, for example, one or more types of anti-glare materials consisting of organic fine particles, inorganic fine particles, and inorganic components, and further contains a binder resin. In order for the surface texture of the low refractive index layer to be good when the low refractive index layer is laminated on the anti-glare layer, it is desirable to control the relatively large protrusions that form the basis of the surface irregularities of the anti-glare layer, and to minimize particle-induced irregularities on the surface between the protrusions as much as possible. When forming such an anti-glare layer surface shape, if each anti-glare material is used individually, it is preferable to make the thickness of the anti-glare layer at least 1.5 times greater than the average particle diameter. If each anti-glare material is an aggregated particle, it is preferable to make the thickness at least 1.5 times greater than the average particle diameter of the aggregate. The protrusions of the anti-glare layer, for example, in the case of the above-mentioned organic fine particles, may exist individually, but generally, several fine particles exist with narrow spacing between them. In other words, at a minimum, when observing the surface of the anti-glare layer, areas where two or more fine particles are densely clustered tend to form protrusions. This is because, by making the film thickness larger than the average particle diameter, sufficient binder resin can be present on individual fine particles (or aggregates of fine particles smaller than the large aggregates of fine particles that form relatively large protrusions), separate from the aggregates of fine particles that form such relatively large protrusions, making it easier to control the surface shape between the protrusions as described above. Furthermore, it is preferable that the viscosity of the binder resin used at that time is high. The viscosity of the binder resin can be adjusted by the viscosity of the binder resin itself, the solid content between the solvent and solute, and the drying conditions during manufacturing. The binder resin and solvent can be appropriately selected and mixed from those described later. Furthermore, using each anti-glare material individually means not mixing the two types of materials mentioned above: organic fine particles and inorganic fine particles / inorganic components. On the other hand, for example, in the case of organic fine particles, mixing acrylic resin fine particles and styrene-acrylic copolymer fine particles made from different resin materials, or mixing fine particles with different particle sizes, is considered as using them individually. When the above inorganic fine particles and inorganic components, along with multiple types of anti-glare agents such as organic fine particles and a binder resin are included, the surface irregularities may be formed by aggregates of inorganic fine particles and inorganic components and organic fine particles, as described later. In an anti-glare layer formed by this method, the irregularities formed on the surface of the anti-glare layer can be controlled to have fewer particle-induced irregularities on the surface between the main protrusions. This is presumed to be because, as will be described later, the inorganic fine particles and the inorganic components and organic fine particles are distributed in a specific state within the anti-glare layer. In this case, it is preferable that the organic microparticles have a larger particle size than the inorganic microparticles / inorganic components. Inorganic fine particles and inorganic components preferably have an average particle diameter of 10% or less of the average particle size of organic fine particles. However, this does not apply if the shape of the inorganic fine particles or inorganic components is spherical or irregular with a major axis / minor axis ratio of less than 5, but is irregular with a major axis / minor axis ratio of 5 or more, or is in a layered, thin flake state, in which case they may be larger or smaller than organic fine particles.

[0064] It is preferable that the above inorganic fine particles and inorganic components are contained in the anti-glare layer in a densely and coarsely distributed manner, forming aggregates. This is preferable because the densely and coarsely distributed aggregates of the inorganic fine particles and inorganic components in the anti-glare layer allow for the formation of a surface condition other than the convex parts of the uneven shape on the surface of the anti-glare layer. This surface condition makes it easier to improve the flatness of any 5 μm square region on the surface of the low refractive index layer when the low refractive index layer is laminated, thereby improving scratch resistance. The phrase "distributed densely and sparsely within the anti-glare layer" means that the anti-glare layer contains multiple regions where the inorganic fine particles and aggregates of inorganic components are densely distributed, and regions where the inorganic fine particles and aggregates of inorganic components are sparsely distributed. In other words, the inorganic fine particles and aggregates of inorganic components are non-uniformly dispersed within the anti-glare layer. In this specification, when observing any cross-section in the thickness direction of the anti-glare layer at a magnification of 10,000x using an electron microscope (transmission type such as TEM or STEM is preferred, for example, using the observation conditions described above), a region where the area ratio of inorganic fine particles and aggregates of the inorganic components in a 2 μm square observation area is 5% or more is defined as a "region where inorganic fine particles and aggregates of the inorganic components are densely distributed," and a region where the area ratio of inorganic fine particles and aggregates of the inorganic components in a 2 μm square observation area is less than 1% is defined as a "region where inorganic fine particles and aggregates of the inorganic components are loosely distributed." Furthermore, regions in which the inorganic fine particles and aggregates of the inorganic components are densely distributed, or regions in which the inorganic fine particles and aggregates of the inorganic components are loosely distributed, that is, regions observed under the conditions of 10,000x magnification with the electron microscope, can be selected, for example, by observing the distribution state of inorganic fine particles in the cross-section in the thickness direction of the anti-glare layer with an electron microscope under low magnification conditions of about 3,000x. The distribution of such inorganic microparticles and inorganic component aggregates can be easily determined by cross-sectional electron microscopy observation in the thickness direction of the anti-glare layer. Furthermore, the area ratio of the inorganic microparticles and inorganic component aggregates can be calculated, for example, using image analysis software. One example of image analysis software is WinRoof, manufactured by Mitani Corporation. This software can be used to binarize and analyze images of a 2μm square area observed at a magnification of 10,000x.

[0065] The inorganic fine particles are preferably surface-treated. Surface treatment of the inorganic fine particles allows for optimal control of the degree to which aggregates of the inorganic fine particles are distributed densely within the anti-glare layer, and also allows for control of the effect of dense distribution around organic fine particles within an appropriate range. Furthermore, it is possible to improve the chemical resistance and saponification resistance of the inorganic fine particles themselves.

[0066] The surface treatment described above is preferably a hydrophobic treatment, and examples include treating the inorganic fine particles with a hydrophobic agent such as a silane compound having an alkyl group. Examples of the alkyl groups mentioned above include methyl, ethyl, propyl, butyl, hexyl, and octyl groups. Examples of silane compounds having the alkyl groups mentioned above include methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, trimethylsilanol, hexamethyldisilazane, methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, and octyltrimethoxysilane. Here, preferred materials for the inorganic nanoparticles mentioned above include, for example, silica, alkali metal oxides, alkaline earth oxides, titanium oxides, zinc oxides, aluminum oxides, boron oxides, tin oxides, phosphorus oxides, indium tin oxides, zirconium oxides, and so on, with silica nanoparticles being particularly versatile as the inorganic nanoparticles. Normally, hydroxyl groups (silanol groups) are present on the surface of silica nanoparticles. However, the above surface treatment reduces the number of hydroxyl groups on the surface of the silica nanoparticles, preventing excessive aggregation of the silica nanoparticles and thus achieving the effects described above. Furthermore, it is preferable to control the aggregation of the silica microparticles by adjusting the degree of hydrophobicity of the silica microparticle surface depending on the type of hydrophobic agent used. For example, by lengthening the alkyl chain of the silane compound having an alkyl group, the steric hindrance effect of the silane compound having an alkyl group increases, and as a result, the degree of hydrophobicity of the silica microparticle surface can be reduced.

[0067] Furthermore, it is preferable that the above-mentioned silica nanoparticles are made of amorphous silica. If the above-mentioned silica nanoparticles are made of crystalline silica, the Lewis acidity of the silica nanoparticles may become strong due to lattice defects contained in the crystal structure, making it impossible to control the excessive aggregation of the silica nanoparticles as described above.

[0068] As such silica nanoparticles, fumed silica is preferably used because it readily aggregates and forms aggregates as described later. Here, fumed silica refers to amorphous silica with a particle size of 200 nm or less, produced by a dry process, and is obtained by reacting a silicon-containing volatile compound in the gas phase. Specifically, examples include silicon compounds, such as those produced by hydrolyzing SiCl4 in an oxygen and hydrogen flame. Specifically, examples include AEROSIL R805 (manufactured by Nippon Aerosil Co., Ltd.).

[0069] The content of the above-mentioned silica fine particles is not particularly limited, but it is preferably 0.1 to 5.0% by mass in the anti-glare layer. If it is less than 0.1% by mass, a dense distribution may not be sufficiently formed around the above-mentioned organic fine particles, making it difficult to form a surface condition of the anti-glare layer that is desirable for improving scratch resistance. If it exceeds 5.0% by mass, excessive aggregates may form and internal diffusion may occur, which may reduce transparency and cause a whitish appearance. A more preferable lower limit is 0.5% by mass, and a more preferable upper limit is 3.0% by mass.

[0070] The above silica nanoparticles preferably have an average particle diameter of 1 to 100 nm. If the diameter is less than 1 nm, a sufficiently dense distribution may not be formed around the organic nanoparticles, and if it exceeds 100 nm, a sufficiently dense distribution may not be formed around the organic nanoparticles. A more preferable lower limit is 5 nm, and a more preferable upper limit is 50 nm. The average particle size of the above-mentioned silica nanoparticles can be determined by visually observing and measuring the particle size of 50 randomly selected particles from images taken with a cross-sectional electron microscope (transmission type such as TEM or STEM, preferably with a magnification of 1 to 100,000x or more), and then calculating the average value. Alternatively, the average value can also be measured using image processing software (for example, WinRoof, manufactured by Mitani Corporation) from the above images. Since both methods use cross-sectional observation images, almost identical measurement results can be obtained.

[0071] Furthermore, the aggregate of silica nanoparticles may form a structure in which the silica nanoparticles are linked together in a bead-like (pearl necklace-like) manner within the anti-glare layer. As the silica fine particles in the anti-glare layer form aggregates linked together in a bead-like manner, it is possible to suitably form surface conditions other than the convex parts of the surface irregularities of the anti-glare layer, as will be described later. The above-mentioned structure in which silica nanoparticles are linked together in a bead-like manner can refer to any structure, such as a structure in which the silica nanoparticles are linked together in a straight line (linear structure), a structure in which multiple linear structures are intertwined, or a branched structure having one or more side chains in which multiple silica nanoparticles are continuously formed on the linear structure.

[0072] Furthermore, the aggregates of silica microparticles preferably have an average particle diameter of 100 nm to 2 μm. If it is less than 100 nm, the buffering effect of the formation of irregularities in the aggregates due to curing shrinkage, which will be described later, may not be fully exerted, and if it exceeds 2 μm, a sufficiently dense distribution may not be formed around the organic microparticles, and light may be diffused by the aggregates of silica microparticles, or the surface irregularities caused by the aggregates may become too large, resulting in poor contrast between the bright and dark rooms of the image display device. A more preferable lower limit for the average particle diameter of the aggregates is 200 nm, and a more preferable upper limit is 1 μm. Since the shape of the aggregates is not fixed, 2 μm and 1 μm often refer to the longest diameter of the aggregate. The average particle size of the silica microparticle aggregates described above is determined by selecting a 5 μm square region containing many silica microparticle aggregates from observation using a cross-sectional electron microscope (approximately 10,000 to 20,000 times magnification), measuring the particle size of the silica microparticle aggregates within that region, and averaging the particle sizes of the top five silica microparticle aggregates, excluding the largest one. The "particle size of the silica microparticle aggregates" described above is measured as the distance between two parallel lines that maximize the distance between the two lines when the cross-section of the silica microparticle aggregate is enclosed by those two lines. Alternatively, the particle size of the silica microparticle aggregates may be calculated using image analysis software.

[0073] Furthermore, it is preferable that the silica fine particles are densely distributed in aggregates around the organic fine particles contained in the anti-glare layer. Furthermore, as described above, it is preferable that the aggregates of silica microparticles are contained in the anti-glare layer in a sparse-to-dense manner, and it is preferable that the anti-glare layer has regions in which numerous aggregates of silica microparticles exist around the organic microparticles, and regions in which only aggregates of silica microparticles are densely distributed. For example, the state in which aggregates of silica microparticles are densely distributed around the organic microparticles can be easily confirmed by electron microscope observation of a cross-section of the anti-glare layer. When the cross-section of the anti-glare layer is observed with an electron microscope, it is observed that the aggregates of silica microparticles densely distributed around the organic microparticles are densely distributed not only in the cross-section passing through the center of the organic microparticles, but also in the cross-section offset from the center of the organic microparticles. Furthermore, the statement "aggregates of silica microparticles are densely distributed around the organic microparticles" means that when the cross-section in the thickness direction of the anti-glare layer where the organic microparticles are observed is observed under a microscope at a magnification of 20,000x using an electron microscope (transmission type such as TEM or STEM is preferred), the area ratio of aggregates of silica microparticles in the region excluding the organic microparticles, within the circumference 200 nm outside the organic microparticles, is 10% or more.

[0074] The inclusion of silica microparticle aggregates and organic microparticles in the anti-glare layer is preferable because, when the low refractive index layer is laminated on top of the anti-glare layer, the surface texture of the low refractive index layer is good, and a shape can be created that allows control of Ra and Rz within a specific range, thereby improving scratch resistance. It is presumed that such a shape can be achieved for the following reasons. In other words, when the anti-glare layer composition is applied and dries, causing the solvent to evaporate, if the viscosity of the binder resin is low, the binder resin tends to conform to the shape of the organic microparticles. Furthermore, if the binder resin consists only of polyfunctional monomers, it may shrink in volume when cured, but since organic microparticles are in a polymer state, they do not shrink. As a result, only the binder resin shrinks, causing relatively large protrusions to form on the surface at locations corresponding to where two or more organic microparticles aggregate, for example, to have a steep slope. In addition, small protrusions, such as those caused by individual organic microparticles, are likely to form between the relatively large protrusions that form the base of such uneven shapes. However, due to the dense distribution of silica microparticle aggregates around the organic microparticles, the viscosity around the organic microparticles in the anti-glare layer composition increases. When the solvent evaporates, the binder resin has difficulty following the shape of the organic microparticles, and the binder (consisting of binder resin and silica microparticles) in that area is less likely to shrink during curing. Furthermore, when silica microparticles form aggregates, they are loosely aggregated and contain the binder resin, thus providing a buffer against curing shrinkage. As a result, the steep slope of relatively large protrusions formed on the surface at positions corresponding to aggregates of several or more organic microparticles is suppressed. Additionally, because there is a buffer around organic particles that exist individually (or in aggregates smaller than those forming relatively large protrusions), the areas between relatively large protrusions, i.e., the surfaces other than the protrusions, become highly flat. Therefore, it is presumed that the state of the surfaces other than the protrusions of the uneven shape formed on the surface of the anti-glare layer by the above organic fine particles is easily controlled to a desirable state. The above reason has been described using silica fine particles as an example, but it is not limited to silica fine particles; when other inorganic fine particles or inorganic components are used in combination with the above organic fine particles, aggregates of inorganic fine particles and inorganic components are formed, and it is thought that a good surface shape of the anti-glare layer can be formed by a similar mechanism. As mentioned above, even with an anti-glare layer composition containing only organic fine particles, an anti-glare layer with a suitable surface condition can be formed by controlling the viscosity and film thickness of the binder resin. When comparing an anti-glare layer composition containing only organic microparticles with an anti-glare composition containing inorganic microparticles and inorganic components in addition to organic microparticles, the latter material system is superior because it allows for free arrangement of composition viscosity and other properties, regardless of the intrinsic physical properties of the binder resin itself, thus enabling a wider range of surface shape designs.

[0075] Furthermore, in the anti-glare layer described above, it is preferable that the organic fine particles and silica fine particles have a spherical shape in their single-particle state. Because the single particles of the organic fine particles and silica fine particles are spherical in this way, when applied to an image display device, a high-contrast display image can be obtained. The term "spherical" above refers to shapes such as perfect spheres and ellipsoids, and excludes so-called amorphous shapes.

[0076] The above-mentioned organic fine particles are mainly those that form the surface irregularities of the anti-glare layer, and are fine particles whose refractive index and particle size can be easily controlled. By including such organic fine particles, it becomes easy to control the size of the irregularities formed on the anti-glare layer. Furthermore, because the refractive index difference between the above-mentioned organic fine particles and the binder resin can be easily controlled, it is possible to control the anti-glare properties and maintain transparency, and suppress the occurrence of whitishness.

[0077] The content of the above-mentioned organic fine particles is preferably 0.5 to 10.0% by mass in the anti-glare layer. If it is less than 0.5% by mass, the anti-glare performance may be insufficient, and if it exceeds 10.0% by mass, it may be difficult to obtain a surface condition of the anti-glare layer that can improve scratch resistance, and the transparency may decrease, causing a whitish appearance, and the contrast of the displayed image may be inferior when used in an image display device. A more preferable lower limit is 1.0% by mass, and a more preferable upper limit is 8.0% by mass.

[0078] Furthermore, the size of the organic fine particles is appropriately determined in accordance with the thickness of the anti-glare layer, etc., but for example, an average particle diameter of 0.3 to 5.0 μm is preferable. If it is less than 0.3 μm, there is a risk that the dispersibility of the organic fine particles will not be controllable, and if it exceeds 5.0 μm, the convex shape of the surface of the anti-glare layer will become large, making it difficult to obtain a surface condition of the anti-glare layer that can improve scratch resistance. A more preferable lower limit is 1.0 μm, and a more preferable upper limit is 3.0 μm. Furthermore, the average particle size of the above-mentioned organic fine particles is preferably 20-60% of the thickness of the anti-glare layer. If it exceeds 60%, the organic fine particles may protrude from the surface of the coating layer, and the resulting protrusions may become too large. If it is less than 20%, it may not be possible to form a sufficient convex shape on the surface of the anti-glare layer, resulting in insufficient anti-glare performance. The average particle size of the organic microparticles in the anti-glare layer is determined by observing the anti-glare layer under a transmission optical microscope and averaging the maximum diameter of the particles. In this case, an optical laminate of about 2 cm square is fixed to a glass slide with tape or the like, and three areas considered to be homogeneous surfaces free of foreign matter and scratches are observed at 200 to 500x magnification. The maximum diameters of 15 particles visible within the field of view are measured, and the average particle size is determined by arithmetic mean. Alternatively, if that is unsuitable, the value is calculated by selecting 30 diffuse particles of any kind with approximately the same particle size (the number of particles is increased because it is unknown which part of the particle the cross-section is from) from an electron microscope (transmission type such as TEM or STEM is preferred) observing a cross-section passing near the center of the particle, measuring the maximum particle size of that cross-section, and calculating the average value. In either case, since it is determined from the image, it may also be calculated using image analysis software. Furthermore, in the case of particles used in the anti-glare layer, the weight-average diameter and the diameter observed under a microscope or similar device do not differ significantly. For example, using the SEM function of a scanning electron microscope (SEM) (product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation), 10 images are taken at 1000 to 20000x magnification. Using the included software, 30 arbitrary particles are selected from the imaged images on the image screen, their maximum particle size is measured, and the arithmetic mean is calculated. Measurement conditions can be, for example, set to "SE" for signal selection, "5kV" for acceleration voltage, "10μA to 20μA" for emission current, "mixed" for SE detector, "Norm" for probe current, "UHR" for focus mode, "5.0" for condenser lens 1, "8mm" for WD, and "30°" for tilt, but are not limited to these. Note that the TE detector is not used during SEM observation, so be sure to remove the TE detector before SEM observation.

[0079] Furthermore, by including clay-based inorganic components, particularly swollen clay, among the inorganic components of the anti-glare layer, it is possible to easily adjust the convex shape and the surface condition of the anti-glare layer other than the convex parts.

[0080] The above-mentioned swellable clay may have cation exchange ability and swell by incorporating water between its layers. It may be a natural product or a synthetic product (including substituted products and derivatives). It may also be a mixture of a natural product and a synthetic product. Examples of the above-mentioned swelling clays include mica, synthetic mica, vermiculite, montmorillonite, iron montmorillonite, beiderite, saponite, hectorite, stevensite, nontronite, magadiite, islarite, kanemite, layered titanate, smectite, synthetic smectite, fine silica, calcium silicate, aluminum silicate, calcium carbonate, magnesium carbonate, fine talc, titanium dioxide, diatomaceous earth, smectite, and kaolin clay. These swelling clays may be used individually or in combination.

[0081] The content of the above-mentioned swelling clay is preferably 0.1 to 10% by mass, and more preferably 0.2 to 5% by mass, based on 100% by mass of the solid content of the binder resin. If the content of the above-mentioned swelling clay is 0.1% by mass, the change in viscosity is small compared to when it is not added, so the effect of controlling the surface condition of the anti-glare layer other than the protrusions may be insufficient. If the content of the above-mentioned swelling clay exceeds 10% by mass, the viscosity may be too high, resulting in insufficient coating suitability.

[0082] Even when the above-mentioned swellable clay inorganic component is used, the anti-glare layer may contain a mixture of organic fine particles, inorganic fine particles, and other inorganic components. By including the above-mentioned organic fine particles, inorganic fine particles, and other inorganic components together with the above-mentioned swellable clay inorganic component, the surface state of the anti-glare layer, other than the relatively large protrusions formed on the surface of the anti-glare layer, can be suitably and diversely controlled. The organic fine particles, inorganic fine particles, and other inorganic components mentioned above can be the same as those exemplified in the anti-glare agents described above.

[0083] The binder resin mentioned above is preferably transparent, and for example, an ionizing radiation-curable resin is preferred. In this specification, unless otherwise specified, the term "resin" encompasses monomers, oligomers, polymers, and the like.

[0084] Examples of ionizing radiation-curable resins include compounds having one or more unsaturated bonds, such as compounds having functional groups like acrylates. Examples of compounds having one unsaturated bond include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, and N-vinylpyrrolidone. Examples of compounds having two or more unsaturated bonds include trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and tripentaerythritol Examples of polyfunctional compounds include quacta(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, isocyanuric acid tri(meth)acrylate, isocyanuric acid di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, diglycerin tetra(meth)acrylate, adamantyl di(meth)acrylate, isobolonyl di(meth)acrylate, dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate. In this specification, "(meth)acrylate" refers to methacrylate and acrylate. Furthermore, in the present invention, the above-mentioned compounds modified with PO, EO, etc., can also be used as ionizing radiation-curable resins.

[0085] In addition to the compounds mentioned above, relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, etc., that have unsaturated double bonds can also be used as the ionizing radiation-curable resins.

[0086] The above-mentioned ionizing radiation-curing resin can also be used in combination with solvent-drying resins (thermoplastic resins, etc., which form a film simply by drying the solvent added to adjust the solid content during coating). By using solvent-drying resins in combination, it is possible to effectively prevent film defects on the coated surface of the coating liquid when forming the anti-glare layer. The solvent-drying resin that can be used in combination with the above-mentioned ionizing radiation-curing resin is not particularly limited, and generally, thermoplastic resins can be used.

[0087] The thermoplastic resins mentioned above are not particularly limited and include, for example, styrene resins, (meth)acrylic resins, vinyl acetate resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, polycarbonate resins, polyester resins, polyamide resins, cellulose derivatives, phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, amino alkyd resins, melamine-urea cocondensation resins, silicon resins, silicone resins, and rubber or elastomers. The thermoplastic resins are preferably amorphous and soluble in organic solvents (especially common solvents capable of dissolving multiple polymers and curable compounds). In particular, from the viewpoint of film-forming properties, transparency, and weather resistance, styrene resins, (meth)acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters, etc.) are preferred.

[0088] An anti-glare layer containing the above-mentioned anti-glare agent and binder resin can be formed, for example, by applying an anti-glare layer composition containing the anti-glare agent, monomer components of the binder resin, and a solvent onto a light-transmitting substrate, drying it, and curing the resulting coating film by irradiation with ionizing radiation or the like.

[0089] The particle size and content of the anti-glare agent and the content of the binder resin are not particularly limited, and the surface shape of the anti-glare layer described later should be appropriately adjusted to satisfy a surface condition that improves scratch resistance when a low refractive index layer is laminated.

[0090] Examples of solvents included in the above-mentioned anti-glare layer composition include alcohols (methanol, ethanol, propanol, butanol, cyclohexanol, isopropyl alcohol, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethyl sulfoxide, etc.), amides (dimethylformamide, dimethylacetamide, etc.), and mixtures thereof.

[0091] The above-mentioned anti-glare layer composition preferably further contains a photopolymerization initiator. The above-mentioned photopolymerization initiator is not particularly limited and includes those similar to the photopolymerization initiator described in the low refractive index layer composition. The above-mentioned photopolymerization initiator may be used alone or two or more may be used in combination. Furthermore, the above-mentioned anti-glare layer composition is preferably used in combination with a photosensitizer, and specific examples of such substances include, for example, n-butylamine, triethylamine, and poly-n-butylphosphine.

[0092] The amount of the photopolymerization initiator in the above-mentioned anti-glare layer composition is preferably 0.5 to 10.0 parts by mass per 100 parts by mass of the binder resin. If the amount is less than 0.5 parts by mass, the hard coat performance of the formed anti-glare layer may be insufficient, and if it exceeds 10.0 parts by mass, it may inhibit curing, which is undesirable.

[0093] The content ratio (solid content) of the raw materials in the above-mentioned anti-glare layer composition is not particularly limited, but is usually 5 to 70% by mass, and particularly preferably 25 to 60% by mass.

[0094] The above-mentioned anti-glare layer composition preferably contains a leveling agent. Examples of the leveling agents mentioned above include fluorine-based leveling agents, silicone-based leveling agents, and silicone / fluorine atom-containing leveling agents, which may be used alone or in combination. Preferably, fluorine-based leveling agents and silicone / fluorine atom-containing leveling agents are used. The above-mentioned anti-glare layer composition preferably contains a leveling agent such as a fluorine-based or silicone-based leveling agent. The inclusion of a leveling agent in the above-mentioned anti-glare layer composition effectively prevents the anti-glare layer from forming a Bénard cell structure. When a resin composition containing a solvent is applied and dried, a difference in surface tension occurs between the surface and the interior of the coating film, causing numerous convection currents within the film. This structure resulting from convection is called a Bénard cell structure, and it can cause problems such as orange peel texture and coating defects in the anti-glare layer formed. Furthermore, the above-mentioned Benard cell structure can have adverse effects, such as excessive surface irregularities in the anti-glare layer, leading to reduced transparency and a whitish appearance, or distortion of transmitted light from inside the display device due to the irregularities in the anti-glare layer, causing scintillation that makes parts of the image appear sparkly. By using the leveling agent described above, this convection can be prevented, resulting in a surface irregularity film without defects or unevenness, as well as easier adjustment of the irregularity shape. Furthermore, when the anti-glare layer composition is applied, the leveling agent contained in it may migrate to the low refractive index layer composition. If there are compatibility issues with the low refractive index layer composition or with components such as the leveling agent and antifouling agent contained in the low refractive index layer composition, the arrangement of hollow silica and the like contained in the low refractive index layer, as described later, may be disrupted, and the uneven surface formed on the low refractive index layer may become larger. In such cases, it is preferable that the above-mentioned anti-glare layer composition contains a non-reactive leveling agent. The above-mentioned non-reactive leveling agent is less likely to cause compatibility issues with the low-refractive-index layer composition described later, and with components such as leveling agents and antifouling agents contained in the low-refractive-index layer composition, thus enabling the formation of suitable uneven surfaces on the low-refractive-index layer.

[0095] As the above-mentioned non-reactive leveling agent, an oligomer containing a lipophilic group is preferably used. The content of the non-reactive leveling agent is preferably 0.025 to 0.50 parts by mass per 100 parts by mass of the binder resin in the anti-glare layer. If the content of the non-reactive leveling agent is less than 0.025 parts by mass, insufficient leveling force may result in uneven appearance. If the content of the non-reactive leveling agent exceeds 0.50 parts by mass, the coating liquid may become prone to foaming, which can lead to defects. A more preferable lower limit for the content of the above-mentioned non-reactive leveling agent is 0.050 parts by mass, and a more preferable upper limit is 0.20 parts by mass.

[0096] The above-mentioned anti-glare layer composition preferably contains only the above-mentioned non-reactive leveling agent as a leveling agent, but may also contain other leveling agents as long as they do not hinder the effects of the present invention.

[0097] The above-mentioned anti-glare layer composition may contain conventionally known dispersants, surfactants, antistatic agents, silane coupling agents, thickeners, color inhibitors, colorants (pigments, dyes), defoamers, flame retardants, ultraviolet absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, lubrication agents, etc., depending on the purpose of increasing the hardness of the anti-glare layer, suppressing curing shrinkage, controlling the refractive index, etc.

[0098] Furthermore, the above-mentioned anti-glare layer composition may be used in combination with a photosensitizer, and specific examples of such substances include, for example, n-butylamine, triethylamine, and poly-n-butylphosphone.

[0099] The method for preparing the above-mentioned anti-glare layer composition is not particularly limited as long as each component can be mixed uniformly, and can be carried out using known devices such as paint shakers, bead mills, kneaders, and mixers.

[0100] The method for applying the above-mentioned anti-glare layer composition onto a light-transmitting substrate is not particularly limited, and known methods such as spin coating, dip coating, spray coating, die coating, bar coating, roll coating, meniscus coating, flexographic printing, screen printing, and speed coating are examples of such methods. After applying the anti-glare layer composition using one of the methods described above, the formed coating film is transported to a heated zone for drying, where it is dried by various known methods to evaporate the solvent. Here, the distribution state of aggregates of organic and silica fine particles can be adjusted by selecting the relative evaporation rate of the solvent, the solid content concentration, the temperature of the coating solution, the drying temperature, the wind speed of the drying air, the drying time, the solvent atmosphere concentration in the drying zone, etc. In particular, a simple and preferred method is to adjust the distribution state of organic and silica microparticle aggregates by selecting drying conditions. Preferably, the drying temperature is 30 to 120°C and the drying air velocity is 0.2 to 50 m / s. By performing the drying treatment, adjusted appropriately within this range, once or multiple times, the distribution state of organic and silica microparticle aggregates can be adjusted to the desired state.

[0101] Furthermore, as a method of irradiating the dried coating with ionizing radiation to harden it, examples include using light sources such as ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arc lamps, black light fluorescent lamps, and metal halide lamps. Furthermore, ultraviolet wavelengths in the 190-380 nm range can be used. Specific examples of electron sources include Cockcroftwald type, Van de Graft type, resonant transformer type, insulated core transformer type, or various electron accelerators such as linear type, dynamitron type, and high-frequency type.

[0102] The thickness of the anti-glare layer described above is preferably 2.0 to 15.0 μm. If it is less than 2.0 μm, the surface of the anti-glare layer may be easily scratched, and if it exceeds 15.0 μm, the anti-glare layer may be easily cracked. A more preferable range for the thickness of the anti-glare layer is 2.0 to 7.0 μm, and even more preferably an upper limit of 5.0 μm. The thickness of the anti-glare layer can be measured by cross-sectional microscopy observation using an SEM or optical microscope. Through observation, it can be calculated as the arithmetic mean of measurements taken at any five points free from foreign objects, damage, etc.

[0103] The optical laminate of the present invention may also optionally have one or more functional layers (such as an antistatic layer, antifouling layer, adhesive layer, anti-reflective layer, or other hard coat layer) formed on the surface of the light-transmitting substrate where the anti-glare layer and the low refractive index layer are not laminated, on the upper surface of the low refractive index layer, or between the light-transmitting substrate and the anti-glare layer, as long as the effects of the present invention are not impaired. In particular, it is preferable to have at least one of the antistatic layer and the antifouling layer. These layers may be the same as those used in known anti-reflective laminates. Furthermore, as described above, the optical laminate of the present invention may have a functional layer such as an anti-fouling layer laminated on top of a low refractive index layer, but the functional layer is an extremely thin film that does not impair optical properties such as scratch resistance and anti-reflective properties. The extremely thin film is, for example, a thin film with a thickness of 35 nm or less, the thinner the better. In other words, the optical laminate of the present invention has the low refractive index layer described above as an essential component, but all physical properties obtained by the optical laminate of the present invention having such a low refractive index layer will be the same even if the above-mentioned ultrathin functional layer is laminated. Therefore, the actual air interface of the optical laminate of the present invention may not be a low refractive index layer.

[0104] Furthermore, the optical laminate of the present invention preferably has a total light transmittance of 85% or more. If it is less than 85%, the transparency will be insufficient, and when the optical laminate of the present invention is mounted on the surface of an image display device, it may impair color reproduction and visibility. The above total light transmittance is more preferably 90% or more, and even more preferably 91% or more. The total light transmittance mentioned above can be measured in accordance with JIS K7361 using a device such as the "HM-150" manufactured by Murakami Color Technology Research Institute. Furthermore, the optical laminate of the present invention is an anti-reflective film having a low refractive index layer on top of an anti-glare layer. The presence of the anti-glare layer alone effectively prevents reflections of surrounding objects, and the presence of the low refractive index layer on top of it improves transparency, resulting in the effect of making images and text appear clearer. Moreover, by controlling the luminous reflectance (%), which is calculated as the brightness perceived by the human eye, rather than simply the 5° specular reflectance (%), a more preferable optical laminate can be made. In the present invention, the preferred luminous reflectance (%) is 3.0% or less, and the lower the better, with 2.0% or less, and even more preferably 1.0% or less. Since it is difficult to achieve almost no reflection, such as about 0.1%, while maintaining physical strength, the preferred range for the optical laminate of the present invention is 0.3% to 1.8% or less, 1.5% or less, and most preferably 1.0% or less. The above luminous reflectance (%) can be determined, for example, by measuring the 5° specular reflectance in the wavelength range of 380 to 780 nm using a spectrophotometer (Shimadzu Corporation, product name: UV-2450), and then calculating it using software (built into the device) that converts it to brightness as perceived by the human eye.

[0105] Furthermore, the optical laminate of the present invention preferably has a haze of less than 15%. The anti-glare layer may consist of internal haze due to internal diffusion by contained fine particles and external haze due to the uneven shape of the surface. The internal haze due to internal diffusion is preferably in the range of 0% to less than 10%, more preferably in the range of 0% to less than 7%, and even more preferably in the range of 0% to less than 5%. The external haze on the surface is preferably in the range of 0% to less than 5%, more preferably in the range of 0% to less than 3%, and even more preferably in the range of 0% to less than 1%. Furthermore, the above internal haze can be calculated as follows: On the surface irregularities of the low refractive index layer of the optical laminate, a resin having the same refractive index as the resin forming the surface irregularities, or a refractive index difference of 0.02 or less, is applied using a wire bar to a dry film thickness of 8 μm (a film thickness that completely eliminates the surface irregularities and makes the surface flat), and after drying at 70°C for 1 minute, 100 mJ / cm² is applied. 2 The film is cured by irradiation with ultraviolet light. This flattens the surface irregularities, resulting in a film with a smooth surface. However, if the composition forming the anti-glare layer with this irregular shape contains a leveling agent or the like, and the resin applied to the surface of the anti-glare layer tends to repel and is difficult to wet, it is advisable to pre-treat the surface of the anti-glare layer with hydrophilic treatment by saponification (immersing in a 2 mol / L NaOH (or KOH) solution at 55°C for 3 minutes, then rinsing with water, completely removing water droplets with Kimwipes®, etc., and drying in a 50°C oven for 1 minute). A film with a flattened surface has no surface irregularities and therefore only possesses internal haze. The internal haze can be determined by measuring the haze of this film using the same method as for haze, according to JIS K-7136. Furthermore, the external haze mentioned above can be calculated as (haze - internal haze). In a simplified approach, an optical transparent adhesive film with an adhesive layer having a lower refractive index than the resin forming the surface irregularities can be used as a substitute for the resin layer in the calculation. In this case, it is advisable to measure the haze of the optical transparent adhesive film beforehand and subtract it from the internal haze.

[0106] The optical laminate of the present invention preferably has a contrast ratio of 80% or more, and more preferably 90% or more. If it is less than 80%, when the optical laminate of the present invention is mounted on the surface of a display, the darkroom contrast may be inferior and visibility may be impaired. In this specification, the above contrast ratio is a value measured by the following method. That is, using a cold cathode fluorescent lamp light source with a diffuser plate as the backlight unit, using two polarizing plates (Samsung AMN-3244TP), and setting the polarizing plates in parallel nicols, the luminance L of the light passing through is... max When set up with crossed nicols, the luminance L of the light passing through is min The value obtained by dividing by (L max / L min The contrast is defined as (L1 / L2) × 100 (%), obtained by dividing the contrast of the optical laminate (light-transmitting substrate + anti-glare layer, etc.) (L1) by the contrast of the light-transmitting substrate (L2). The above luminance measurements will be performed in a darkroom. A colorimeter (Topcon BM-5A) will be used to measure the luminance, with the measurement angle set to 1° and measurements taken over a φ5mm field of view on the sample. The backlight intensity will be set to 3600 cd / m² when two polarizing plates are set to parallel nicols without the sample in place. 2 Install it so that it looks like this.

[0107] Furthermore, the optical laminate of the present invention has a preferred lower limit of 100 for the 60° gloss value, a more preferred lower limit of 105, an even more preferred lower limit of 110, a preferred upper limit of 160, and a more preferred upper limit of 150. The above 60° gloss was determined in %) in accordance with JIS Z 8741 using a precision gloss meter such as the GM-26PRO (Murakami Color Technology Research Institute Co., Ltd.). The sample size was 5 cm x 10 cm, and the measurement was taken by bringing the back side of the sample (the side without the anti-glare layer) into close contact with a blackboard using the air suction method. Figure 3 illustrates the method (angle) for measuring gross thickness in accordance with JIS Z 8741. As shown in Figure 3, 60° represents the image of checking the anti-glare properties when viewed from an oblique angle. In other words, 60° gloss allows for desirable anti-glare control regardless of the viewing angle, even with large screens. Furthermore, the optical laminate of the present invention has a preferred lower limit of 70 for 20° gloss, a more preferred lower limit of 75, an even more preferred lower limit of 80, a preferred upper limit of 150, a more preferred upper limit of 120, and an even more preferred upper limit of 100. As shown in Figure 3, 20° represents the angle at which the anti-glare performance is checked when viewing the screen from directly in front (i.e., 20° from the angle perpendicular to the screen). This is an angle of particular concern for TVs and monitors, whether large or small, and it is important that the anti-glare performance is satisfactory here. Therefore, by controlling this gloss, it is possible to control the anti-glare performance that is desirable as a standard feature. This screen-front direction is the angle range in which the viewer's own reflection is likely to appear, so a surface shape is preferable in which the 20° gloss value in the front direction is smaller than the 60° gloss value when viewed from the diagonal direction mentioned above. A lower gloss value means higher anti-glare performance and less reflection. However, in order to create an optical laminate with excellent anti-reflective performance and high transparency, the anti-glare ratio (%) of the 20° gloss in the front direction to the 60° gloss in the diagonal direction is preferably 65% ​​to 95%. If the percentage is less than 65%, the frontal anti-glare effect tends to be too strong, reducing transparency. If it is greater than 95%, meaning the 20° and 60° gloss levels are roughly the same, the frontal anti-glare effect tends to be too weak, potentially causing the observer's own reflection to be noticeable. By simultaneously satisfying the preferred range of 20° gloss and the preferred range of 60° gloss described above, the optical laminate of the present invention has excellent anti-glare performance. Furthermore, by simultaneously setting the reflectance (visible reflectance), total light transmittance, 20° gloss, and 60° gloss within a desirable range, the visibility of displays such as large screens of 50 inches or more and monitors for watching videos is exceptionally good regardless of the viewing angle. Therefore, this is preferable for the anti-glare properties of the anti-glare layer / low refractive index layer of the optical laminate of the present invention. The optical laminate of the present invention possesses optical properties that make it easily visible from any angle, as well as excellent scratch resistance, making it very suitable for large-screen digital signage and other applications that have become increasingly common in recent years. In this invention, the unit of gross (%) is omitted.

[0108] If, in the optical laminate of the present invention, other components such as a cover glass, film, polarizing element, or display element are further laminated on the light-transmitting substrate surface opposite to the side on which the low refractive index layer is laminated, via an adhesive layer or the like, the optical properties of the optical laminate, such as gloss, reflectance (visible reflectance), total light transmittance, haze, and contrast ratio, may be measured after peeling off and removing the adhesive layer and components, or after pretreatment to make the film thickness of the adhesive layer or the like as thin as possible. On the other hand, mechanical properties such as nanoindentation hardness on the surface side of the low refractive index layer of the optical laminate, as well as the particle size of fine particles in the anti-glare layer, can be measured directly without the above-mentioned pretreatment if the low refractive index layer is laminated on the surface of another component.

[0109] <Size, shape, etc.> The optical laminate of the present invention 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. Furthermore, while the size of the single-wafer disc is not particularly limited, the maximum diameter is approximately 2 to 500 inches. "Maximum diameter" refers to the maximum length when connecting any two points on the optical laminate. For example, if the optical laminate is rectangular, the diagonal of that region is the maximum diameter. If the optical laminate is circular, the diameter is the maximum diameter. Furthermore, when the optical laminate of the present invention is in roll form, the width and length of the long sheet wound into a roll are not particularly limited, but generally the width is 300 to 3000 mm and the length is 50 to 5000 m. The optical laminate of the present invention in roll form can be cut into sheets to match the size of a display device or the like. When cutting, it is preferable to remove the roll ends and other parts where the physical properties are unstable. Furthermore, the shape of the sheet is not particularly limited; for example, it may be a polygon (triangle, quadrilateral, pentagon, etc.), a circle, or a random irregular shape. More specifically, if the optical laminate of the present invention 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 1:1, 3:4, 10:16, 9:16, and 1:2 are possible, but in automotive applications and digital signage where design is important, the aspect ratio is not limited to these.

[0110] Furthermore, the optical laminate of the present invention may further have other optical components such as polarizing elements and phase difference films. For example, an optical laminate of the present invention may have the above-mentioned anti-glare layer on at least one surface of a light-transmitting substrate, and further have a polarizing element. The polarizing element may have a polarizing element protective film on at least one surface. When the optical laminate of the present invention has a polarizing element, the layer configuration includes a configuration in which a light-transmitting substrate and an anti-glare layer are sequentially laminated on at least one side of the polarizing element. Specifically, this includes a configuration in which a light-transmitting substrate and an anti-glare layer are sequentially laminated on one side of the polarizing element, and a polarizing element protective film is laminated on the other side, or a configuration in which polarizing element protective films are laminated on both sides of the polarizing element, and a light-transmitting substrate and an anti-glare layer are sequentially laminated on one of the polarizing element protective films. In these optical laminates, the side with the anti-glare layer is usually the light-emitting surface. The optical laminate having the above-described polarizing element can also be used as a polarizing plate. Such a polarizing plate is also one of the present inventions. In other words, the present invention is a polarizing plate comprising a polarizing element, characterized in that the optical laminate of the present invention is provided on the surface of the polarizing element.

[0111] The polarizing element is not particularly limited, and for example, polyvinyl alcohol film, polyvinyl formal film, polyvinyl acetal film, ethylene-vinyl acetate copolymer saponified film, etc., dyed with iodine or the like and stretched can be used. In the lamination process of the polarizing element and the optical laminate of the present invention, it is preferable to perform saponification treatment on the light-transmitting substrate (triacetylcellulose film). Saponification treatment improves adhesion and also provides an antistatic effect.

[0112] The optical laminate or polarizing plate of the present invention can be suitably used as a display panel and an image display device. The present invention is also a display panel characterized by comprising the optical laminate of the present invention or the polarizing plate of the present invention. Furthermore, the present invention is also an image display device characterized by comprising the optical laminate of the present invention or the polarizing plate of the present invention. The above-mentioned display panel is the viewer-side component of the display. To explain using a liquid crystal display as an example, the display panel is a component consisting of two glass plates enclosing liquid crystal material (for example, a color filter substrate and an array substrate), polarizing elements (such as polarizing elements and a polarizing element protective film), and the optical laminate of the present invention.

[0113] The optical laminate of the present invention is preferably used as a component of an image display device such as a liquid crystal display device, and is preferably arranged so that the upper surface of the optical laminate, such as the anti-glare layer, faces the observer side (the light-emitting surface side of the image display device). Furthermore, it is preferable to install the optical laminate of the present invention on the surface of an image display device, and to arrange it so that the upper surface of the optical laminate, such as the anti-glare layer, faces the observer side (the light-emitting surface side of the display device).

[0114] The optical laminate of the present invention and the polarizing element may be cut to the size of the display device and then bonded together as individual sheets, or roll-shaped members may be bonded together. If roll-shaped members are bonded together, they may then be cut to the size of the display device. When applying the optical laminate of the present invention to a display device such as a liquid crystal display device, the optical laminate in the form of a single sheet or roll may be bonded to a display element, etc., as described later, and then cut to the size of the display device. When cutting, it is preferable to exclude the roll ends and other parts whose physical properties are not stable.

[0115] [Image display device] An image display device equipped with the optical laminate of the present invention is characterized by comprising the aforementioned optical laminate or polarizing plate of the present invention. From the viewpoint of more effectively obtaining the effects of the present invention, it is preferable that the image display device is equipped with the aforementioned optical laminate or polarizing plate of the present invention on the observer side (light-emitting surface side of the image display device) of a display element such as a liquid crystal display element, plasma display element, or organic EL display element. More specifically, it is preferable that the image display device is equipped with the aforementioned optical laminate or polarizing plate of the present invention on the observer-side surface of the display element, and that the upper surface (surface with an uneven shape) of the anti-glare layer or the like of the optical laminate or polarizing plate is positioned on the observer side. The size of the above image display device is not particularly limited, but the maximum diameter is approximately 2 to 500 inches. "Maximum diameter" refers to the maximum length when connecting any two points on the display device. For example, if the display device is rectangular, the diagonal of the area is the maximum diameter, and if it is circular, the diameter is the maximum diameter.

[0116] The above-mentioned image display device may be an LCD, PDP, FED, ELD (organic EL, inorganic EL), microLED display, CRT, tablet PC, touch panel, electronic paper, or other image display device.

[0117] The LCD, a typical example of the above, comprises a transparent display and a light source device that illuminates the transparent display from the back. When the image display device of the present invention is an LCD, the optical laminate of the present invention or the polarizing plate of the present invention is formed on the surface of the transparent display.

[0118] In the case of a liquid crystal display device having the above-described optical laminate, the light source of the light source device is irradiated from below the optical laminate. A phase difference plate may be inserted between the liquid crystal display element and the polarizing plate. Adhesive layers may be provided between each layer of this liquid crystal display device as needed.

[0119] The above-mentioned image display device, a PDP, comprises a surface glass substrate (with electrodes formed on its surface) and a back glass substrate (with electrodes and minute grooves formed on its surface, and red, green, and blue phosphor layers formed in the grooves) positioned opposite the surface glass substrate with a discharge gas sealed between them. When the image display device of the present invention is a PDP, the above-mentioned optical laminate is also provided on the surface of the surface glass substrate or on its front panel (glass substrate or film substrate).

[0120] The above-mentioned image display device may be an ELD (Electroluminescent Display) device that displays an image by depositing a light-emitting material such as zinc sulfide or diamine onto a glass substrate and controlling the voltage applied to the substrate, or an image display device such as a CRT that converts electrical signals into light and generates an image visible to the human eye. In this case, the optical laminate described above is provided on the surface of each of the above-mentioned display devices or on the surface of its front panel.

[0121] The image display device of the present invention can be used for displays in televisions, computers, electronic paper, touch panels, tablet PCs, and the like. In particular, it can be suitably used on the surface of high-definition image displays such as CRTs, liquid crystal panels, PDPs, ELDs, FEDs, and touch panels. It can also be suitably used on the image display surface of foldable, bendable, or rollable image display devices and touch panels. [Effects of the Invention]

[0122] Because the optical laminate of the present invention has the above-described configuration, it can be an optical laminate with excellent scratch resistance. It also has suitable anti-glare properties and excellent transparency. Therefore, the optical laminate of the present invention can be suitably applied to the display surface for high-definition images such as cathode ray tube displays (CRTs), liquid crystal displays (LCDs), plasma displays (PDPs), electroluminescent displays (organic or inorganic ELDs), micro-LED displays, field emission displays (FEDs), touch panels, and electronic paper. It can also be suitably used on the image display surface of foldable, bendable, or rollable image display devices and touch panels. [Brief explanation of the drawing]

[0123] [Figure 1] This diagram illustrates the nanoindentation method. (a) is a schematic diagram showing the process of indenting or unloading the indenter into the sample, and (b) is a graph showing an example of an indentation load-indentation depth curve. [Figure 2] This is a schematic diagram showing an example of a Berkovich indenter. [Figure 3] This diagram illustrates the method (angle) for measuring gross thickness in accordance with JIS Z 8741. [Modes for carrying out the invention]

[0124] The present invention will be described by the following embodiments, but the present invention is not limited to these embodiments. Unless otherwise specified, "parts" and "%" are based on mass.

[0125] Optical laminates according to the examples and comparative examples were manufactured as described below, and their physical properties were measured and evaluated. The results are shown in Tables 1 and 2. For all measurements and evaluations, wrinkle-free and unstained portions of the sample were used, and the measurement sample was taken from the central area, which is considered to be a relatively stable coating film, rather than from the edges of the manufactured sample.

[0126] <First optical laminate of the present invention> (Example 1) A light-transmitting substrate (40 μm thick, triacetylcellulose resin film, product name: TD40UC, manufactured by Fujifilm Corporation) was prepared, and a glare-preventing layer composition with the composition shown below was applied to one side of the light-transmitting substrate to form a coating film. Next, the formed coating film is circulated with 70°C dry air at a flow rate of 0.2 m / s for 15 seconds, and then dried by circulating 70°C dry air at a flow rate of 10 m / s for 30 seconds, thereby evaporating the solvent in the coating film and emitting ultraviolet light with an integrated intensity of 30 mJ / cm². 2 By irradiating the coating film in a manner that would cause it to harden, an anti-glare layer with a thickness of 5 μm (at the time of hardening) was formed. (Composition for anti-glare layer) Tetrafunctional acrylate monomer (product name: SR295, manufactured by Sartomer) 50 parts by mass Urethane acrylate oligomer (product name: UV1700B, manufactured by Nippon Synthetic Chemical Co., Ltd.) 50 parts by mass Irgacure 184 (manufactured by BASF Japan) 3 parts by mass Non-reactive fluorine-based leveling agent (product name: F554, manufactured by DIC Corporation) 0.1 parts by mass Organic fine particles (average particle size: 2.0 μm, spherical polyacrylic-styrene copolymer, manufactured by Sekisui Chemical Co., Ltd.) 3 parts by mass Fumed silica (octylsilane treated; average particle size 12 nm, manufactured by Nippon Aerosil Co., Ltd.) 1 part by mass Methyl isobutyl ketone 160 parts by mass Isopropyl alcohol 40 parts by mass

[0127] Next, a low refractive index layer composition with the following composition is applied to the surface of the formed anti-glare layer so that the film thickness after drying (40°C x 1 minute) is 0.11 μm. Then, using an ultraviolet irradiation device (Fusion UV System Japan, light source H bulb), the light is irradiated under a nitrogen atmosphere (oxygen concentration 200 ppm or less) with an integrated light intensity of 100 mJ / cm². 2 A low refractive index layer was formed by curing with ultraviolet irradiation, and an optical laminate according to Example 1 was fabricated. (Composition for low refractive index layer) Trifunctional acrylate monomer (product name: SR444, manufactured by Sartomer) 100 parts by mass Hollow silica nanoparticles (average particle size: 50 nm, manufactured by JGC Catalysts & Chemicals Co., Ltd.) 180 parts by mass Solid silica microparticles (average particle size: 12 nm, manufactured by Nissan Chemical Corporation) 60 parts by mass Irgacure 184 (manufactured by BASF Japan) 10 parts by mass Reactive fluorine-based leveling agent (RS-78, manufactured by DIC Corporation) 8 parts by mass 10,000 parts by mass of methyl isobutyl ketone

[0128] (Example 2) A low refractive index layer composition was prepared in the same manner as in Example 1, except that the amount of solid silica fine particles blended in the low refractive index layer composition was 20 parts by mass. An optical laminate according to Example 2 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0129] (Example 3) A low refractive index layer composition was prepared in the same manner as in Example 1, except that the amount of solid silica fine particles blended in the low refractive index layer composition was 100 parts by mass. An optical laminate according to Example 3 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0130] (Example 4) A low refractive index layer composition was prepared in the same manner as in Example 1, except that solid silica fine particles were not added to the low refractive index layer composition. An optical laminate according to Example 4 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0131] (Example 5) An anti-glare layer composition was prepared in the same manner as in Example 4, except that 0.1 parts by mass of a non-reactive fluorine-based leveling agent (F551, manufactured by DIC Corporation) was used instead of a non-reactive fluorine-based leveling agent (product name: F554, manufactured by DIC Corporation) in the anti-glare layer composition. An optical laminate according to Example 5 was then fabricated in the same manner as in Example 4, except that the said anti-glare layer composition was used.

[0132] (Example 6) A low refractive index layer composition was prepared in the same manner as in Example 1, except that the amount of solid silica fine particles blended in the low refractive index layer composition was 110 parts by mass. An optical laminate according to Example 6 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0133] (Example 7) A low refractive index layer composition was prepared in the same manner as in Example 1, except that the amount of solid silica fine particles blended in the low refractive index layer composition was 80 parts by mass. An optical laminate according to Example 7 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0134] (Example 8) A low refractive index layer composition was prepared in the same manner as in Example 7, except that the trifunctional acrylate monomer in the low refractive index layer composition was replaced with a bifunctional acrylate monomer (product name: M240, manufactured by Toagosei Co., Ltd.). An optical laminate according to Example 8 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0135] (Example 9) A low refractive index layer composition was prepared in the same manner as in Example 7, except that the trifunctional acrylate monomer in the low refractive index layer composition was replaced with a hexafunctional acrylate monomer (product name: DPHA, manufactured by Sartomer). An optical laminate according to Example 9 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0136] (Example 10) A composition for a low refractive index layer was prepared in the same manner as in Example 1, except that a silicane-fluorine atom-containing additive (KY-1203, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of a reactive fluorine-based leveling agent (RS-78, manufactured by DIC Corporation) in the composition for the low refractive index layer. An optical laminate according to Example 10 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0137] (Example 11) A low refractive index layer composition was prepared in the same manner as in Example 1, except that a silicone-based leveling agent (KP-611, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of a reactive fluorine-based leveling agent (RS-78, manufactured by DIC Corporation) in the low refractive index layer composition. An optical laminate according to Example 11 was then fabricated in the same manner as in Example 1, except that the low refractive index layer composition was used.

[0138] (Comparative Example 1) An anti-glare layer composition was prepared in the same manner as in Example 4, except that 0.1 parts by mass of a silicon-based leveling agent (TSF4460, manufactured by Momentive Performance Materials) was used instead of a non-reactive fluorine-based leveling agent (product name: F554, manufactured by DIC Corporation) in the anti-glare layer composition. An optical laminate according to Comparative Example 1 was then fabricated in the same manner as in Example 4, except that the said anti-glare layer composition was used.

[0139] (Comparative Example 2) A low refractive index layer composition was prepared in the same manner as in Comparative Example 1, except that 100 parts by mass of a bifunctional acrylate monomer (product name: SR238F, manufactured by Sartomer) was used instead of a trifunctional acrylate monomer (product name: SR444, manufactured by Sartomer) in the low refractive index layer composition. An optical laminate according to Comparative Example 2 was then fabricated in the same manner as in Comparative Example 1, except that the low refractive index layer composition was used.

[0140] (Measurement of arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the low refractive index layer surface) The following measurements and calculations were performed using an AFM:SPM-9600 (manufactured by Shimadzu Corporation). The definition of surface roughness parameters obtained by AFM is specified in JIS B0031 (1994), but in the case of AFM, it can be calculated as the average surface value within the scanning range (field of view) using the software included with the SPM-9600. However, the above AFM measurements were performed excluding areas where defects such as specific detachment or unevenness were observed. Cantilever: NCH-W (Nano World) Scanning range: 5 μm (field of view: 5 μm x 5 μm) Scanning speed: 1Hz Analysis software: SPM Manager Version 4.36.10 <Preparation of measurement samples> Measurement samples were prepared in the following order (1) to (4). (1) Attach carbon tape to the sample stage and peel off the release paper with tweezers. (2) Hold the edge of the sample with tweezers and cut it with scissors. Cut it into 8mm x 8mm pieces, smaller than the carbon tape, to create the sample. (3) Remove any foreign matter by blowing on both sides of the sample with a blower. (4) With the sample surface (measurement surface) facing upwards, carbon tape was attached to the back of the sample to prepare the measurement sample. <Arithmetic mean roughness Ra> The arithmetic mean roughness Ra was obtained in accordance with JIS B0031 (1994). A reference length (l) was extracted from the surface roughness curve of the obtained measurement sample in the direction of the mean line. The X-axis was drawn in the direction of the mean line of this extracted portion, and the Y-axis was drawn in the direction of the vertical magnification. When the roughness curve was represented as y=f(x), the value obtained by the following formula was expressed in micrometers (μm) to obtain Ra.

number

number

[0141] (Hardness of the low refractive index layer surface: Measurement of nanoindentation hardness (MPa)) The following measurements were taken using the HYSITRON TI950 TriboIndenter in displacement control mode. In the low refractive index layer, a Berkovich indenter (triangular pyramidal, diamond, 115-degree ridge angle) was pressed in for 30 nm at a loading rate of 10 nm / s, held for a certain period of time to allow residual stress to relax, and then unloaded to obtain a load-displacement curve. Subsequently, the indentation hardness was automatically calculated by the device. Calculation Overview: Using the unloading curve, the contact depth (the depth to which the sample is in contact with the indenter) is calculated, and the contact projected area (A(nm)) is calculated from that contact depth. 2 The area is determined, and using this area and the maximum load after relaxation (Pmax (μN)), the indentation hardness is automatically calculated by the device using Pmax / A. In order to obtain stable measurement results, the sample surface was observed using a microscope at magnifications of 50 to 500x, and measurements were taken by selecting the flattest possible area without any unusual defects, while avoiding areas with extremely uneven structures.

[0142] <Preparation of measurement samples> An optical laminate cut to a size of 20 mm x 20 mm was fixed to a commercially available microscope slide with the low refractive index layer facing upwards, using adhesive resin (product name "Aron Alpha (registered trademark) General Use," manufactured by Toagosei Co., Ltd.). Specifically, the adhesive resin was dropped into the center of microscope slide 1 (product name "Slide Glass (Cut Type) 1-9645-11," manufactured by AS ONE Corporation). At this time, only one drop was dropped so as not to spread the adhesive resin and so as not to spill out from the optical laminate when it was spread as described later. Subsequently, the optical laminate cut to the above size was placed in contact with the glass slide so that the low refractive index layer side was facing upwards and the adhesive resin was positioned in the center of the optical laminate. The adhesive resin was then spread between the glass slide 1 and the optical laminate to temporarily bond them together. Then, another new slide glass 2 was placed on top of the optical laminate to obtain a laminate of slide glass 1 / adhesive resin / optical laminate / slide glass 2. Next, a weight of 30g to 50g was placed on slide glass 2, and the sample was left at room temperature for 12 hours. After that, the weight and slide glass 2 were removed, and this was used as the measurement sample. The obtained measurement samples were then fixed to the measurement stage of a HYSITRON "TI950 TriboIndenter" which was installed parallel to the vibration isolation table. Indentation hardness is determined by measuring five arbitrary points near the center of the low refractive index layer surface of the sample (the region where the adhesive resin is present), and taking the arithmetic mean of the hardness of the five points obtained. However, the five points to be measured were selected from the flattest possible areas, avoiding areas with extremely convex or extremely concave structures, by observing the low refractive index layer with a microscope at a magnification of 50x to 500x.

[0143] Indenter used: Berkovich indenter (triangular pyramidal, diamond, 115-degree ridge angle) Measurement conditions: Displacement control method Displacement control mode Maximum displacement: 30nm Time to reach maximum displacement: 3 seconds Holding time at maximum displacement: 5 seconds Unloading time at maximum displacement: 3 seconds Test score: 5 points Temperature at time of measurement: 25℃ Humidity at time of measurement: 50%

[0144] (Scratch resistance test) A scratch resistance test was conducted using a steel wool testing machine: SAM JEE TECH, model number SJTR-053, under the following conditions. [Preparing the steel wool] Cut the steel wool into squares (7cm x 7cm). Secure the steel wool using cable ties so that it fits into the lower of the two recesses on the steel wool test head. Ensure that the steel wool is attached without wrinkles or sagging. Set the test direction of the steel wool so that it is perpendicular to the direction of the steel wool fibers. [Check for levelness] Loosen the stopper so that the head can move freely up and down. With the weight removed, set "CYLINDER" to DOWN and lower the head to check if it is level. [Leveling the steel wool] Because the steel wool had a fuzzy surface, it was smoothed out by "leveling" the surface. <Break-in conditions> Weight 500g, test speed (100mm / s), 200 cycles. [Setting up the test specimen] Sample size: Short side 3cm, Long side 25cm If there is any debris on the cut test piece or base, gently wipe it off with a cloth or similar material. Place the test specimen on the base with the coated side facing up, ensuring there is no slack. [test] Specified load: 700g / cm 2 , test speed (100 mm / s) Temperature during testing: 25°C, Humidity during testing: 50% [evaluation] After the test, apply black vinyl tape (Yamato Vinyl Tape No. 200-38-21, 38mm wide) and check for scratches or discoloration under a three-wavelength fluorescent lamp (1300-1700 lux). The angle between the light source and the test specimen, and between the test specimen and the inspector, should be approximately 45 degrees, and the judgment should be made at an angle where scratches and discoloration are particularly visible. The folded portion (3 cm from both ends) is not considered because it is prone to scratches. The low refractive index layer surface was then visually inspected for scratches and evaluated according to the following criteria. ◎: No scratches or discoloration. ○: Slight discoloration is visible. △: Slight scratches and discoloration are visible. ×: Visible damage or discoloration

[0145] (Measurement of 5° specular reflectance) After attaching a black vinyl tape (Yamato Vinyl Tape No. 200-38-21, 38 mm wide) to the side opposite to the side where the low refractive index layer of each optical laminate is provided, which is the measurement side, the 5° specular reflectance (%) of the surface of the optical laminate was measured in the wavelength range from 380 to 780 nm using an ultraviolet-visible spectrophotometer (UV-2450, manufactured by Shimadzu Corporation). (Reflectance: Measurement of perceived reflectance) Using the measured 5° specular reflectance (%) data, the value indicating the perceived reflectance, which is calculated by software (built into the device) that converts it to the brightness perceived by the human eye, was determined as the reflectance (%). For each sample, the average value of the reflectance at five locations was taken as the reflectance (%) of each sample: the measurement result of the perceived reflectance (Table 1).

[0146]

Table 1

[0147] In the optical laminate according to the embodiment where the Ra of the unevenness in an arbitrary 5 μm square region on the surface of the low refractive index layer is 4 nm or less and the Rz is 60 nm or less, both the scratch resistance and the antireflection performance were excellent. Among them, in Examples 4 and 5 where the Ra in the microscopic view is 2.0 nm or less, the Rz is 25 nm or less, and the indentation hardness is 440 MPa or more, and in Example 7 where the Ra in the microscopic view is 3.0 nm or less, the Rz is 45 nm or less, and the indentation hardness is 500 MPa or more, the scratch resistance was excellent. In particular, in Examples 1 and 2 where the Ra in the microscopic view is 2.0 nm or less, the Rz is 35 nm or less, and the indentation hardness is 500 MPa or more, and in Example 9 where the Ra in the microscopic view is 3.0 nm or less, the Rz is 45 nm or less, and the indentation hardness is 600 MPa or more, the scratch resistance was extremely excellent. On the other hand, in the optical laminate according to the comparative example in which the Ra and Rz of the unevenness in any 5 μm square region on the surface of the low refractive index layer deviate from a specific range, those excellent in both scratch resistance and antireflection performance could not be obtained. In addition, the total light transmittance of the optical laminate according to the first embodiment of the present invention, measured using "HM-150" manufactured by Murakami Color Research Laboratory in accordance with JIS K7361, was all 90% or more. The 20° gloss value measured in accordance with JIS Z 8741 using a precision gloss meter GM-26PRO (Murakami Color Research Laboratory Co., Ltd.) was included in the range of 80 to 140, and the 60° gloss value was included in the range of 110 to 160. Also, 20° gloss value / 60° gloss value × 100 (%) was 70 to 90 (%). The size of the sample at the time of gloss measurement was 5 cm × 10 cm, and the measurement was the average value measured three times by closely adhering the back surface of the sample to a blackboard by the air suction method as the measured value.

[0148] <The optical laminate of the second invention of the present invention>

[0149] (Example 12) A light-transmissive substrate (thickness: 40 μm, triacetyl cellulose resin film, product name: TD40UC, manufactured by Fujifilm Corporation) was prepared, and a composition for an antiglare layer having the following composition was applied to one side of the light-transmissive substrate to form a coating film. Next, with respect to the formed coating film, after flowing dry air at 70 °C at a flow rate of 0.2 m / s for 15 seconds, the solvent in the coating film was evaporated by further flowing dry air at 70 °C at a flow rate of 10 m / s for 30 seconds, and ultraviolet rays were irradiated so that the integrated light amount became 30 mJ / cm 2 to cure the coating film, thereby forming an antiglare layer with a thickness of 5 μm (when cured). (Composition for antiglare layer) 50 parts by mass of a tetrafunctional acrylate monomer (product name: SR295, manufactured by Sartomer) 50 parts by mass of a urethane acrylate oligomer (product name: UV1700B, manufactured by Nippon Synthetic Chemical Co., Ltd.) 3 parts by mass of Irgacure 184 (manufactured by BASF Japan) Non-reactive fluorine-based leveling agent (product name: F554, manufactured by DIC Corporation) 0.1 parts by mass Organic fine particles (average particle size: 2.0 μm, spherical polyacrylic-styrene copolymer, manufactured by Sekisui Chemical Co., Ltd.) 3 parts by mass Fumed silica (octylsilane treated; average primary particle size 12 nm, manufactured by Nippon Aerosil Co., Ltd.) 1 part by mass Methyl isobutyl ketone 160 parts by mass Isopropyl alcohol 40 parts by mass

[0150] Next, a low refractive index layer composition with the following composition is applied to the surface of the formed anti-glare layer so that the film thickness after drying (40°C x 1 minute) is 0.11 μm. Then, using an ultraviolet irradiation device (Fusion UV System Japan, light source H bulb), the light is irradiated under a nitrogen atmosphere (oxygen concentration 200 ppm or less) with an integrated light intensity of 100 mJ / cm². 2 The optical laminate according to Example 10 was fabricated by curing it with ultraviolet irradiation to form a low refractive index layer. (Composition for low refractive index layer) Trifunctional acrylate monomer (product name: SR444, manufactured by Sartomer) 100 parts by mass Hollow silica microparticles (average primary particle size: 50 nm, product name: Thru-Ria DAS, manufactured by JGC Catalysts & Chemicals Co., Ltd.) 180 parts by mass Solid silica microparticles (average primary particle size: 12 nm, product name: MIBK-AC-2140Z, manufactured by Nissan Chemical Corporation) 10 parts by mass Irgacure 184 (manufactured by BASF Japan) 10 parts by mass Reactive silicone leveling agent (RS-57, manufactured by DIC Corporation) 3 parts by mass 10,000 parts by mass of methyl isobutyl ketone

[0151] (Example 13) A low refractive index layer composition was prepared in the same manner as in Example 10, except that solid silica fine particles were not added to the low refractive index layer composition. An optical laminate according to Example 13 was then fabricated in the same manner as in Example 12, except that the low refractive index layer composition was used.

[0152] (Example 14) A composition for a low refractive index layer was prepared in the same manner as in Example 1, except that a reactive silicate-based leveling agent (RS-57, manufactured by DIC Corporation) was replaced with a reactive fluorine-based leveling agent (RS-71, manufactured by DIC Corporation) in the composition for the low refractive index layer. An optical laminate according to Example 14 was then fabricated in the same manner as in Example 12, except that the low refractive index layer composition was used.

[0153] (Example 15) An anti-glare layer composition was prepared in the same manner as in Example 12, except that the amount of urethane acrylate oligomer used was 100 parts by mass. An optical laminate according to Example 13 was then fabricated in the same manner as in Example 15, except that the anti-glare layer composition was used.

[0154] (Example 16) A low refractive index layer composition was prepared in the same manner as in Example 12, except that the trifunctional acrylate monomer in the low refractive index layer composition was replaced with a hexafunctional acrylate monomer (product name: DPHA, manufactured by Sartomer). An optical laminate according to Example 16 was then fabricated in the same manner as in Example 12, except that the low refractive index layer composition was used.

[0155] (Comparative Example 3) A low refractive index layer composition was prepared in the same manner as in Example 12, except that methyl isobutyl ketone / methyl ethyl ketone (5,000 parts by mass / 5,000 parts by mass) was used as a solvent instead of 10,000 parts by mass of methyl isobutyl ketone. An optical laminate according to Comparative Example 3 was then fabricated in the same manner as in Example 12, except that the low refractive index layer composition was used.

[0156] (Comparative Example 4) A low refractive index layer composition was prepared in the same manner as in Example 12, except that the amount of solid silica fine particles blended in the low refractive index layer composition was 60 parts by mass. An optical laminate according to Comparative Example 4 was then fabricated in the same manner as in Example 12, except that the low refractive index layer composition was used.

[0157] (Measurement of arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the low refractive index layer surface) Using AFM: SPM-9600 (manufactured by Shimadzu Corporation), measurements were taken and calculated under the following conditions. The definition of the surface roughness parameters obtained by AFM is as defined in JIS B0031 (1994). However, in the case of AFM, it can be calculated using the software attached to SPM-9600 as the surface average value within the scanning range (field area). However, the above AFM measurements were taken excluding locations where specific peeling, unevenness, or other defects were observed. Cantilever: NCH-W (NanoWorld) Scanning range: 5 μm (field area 5 μm × 5 μm) Scanning speed: 1 Hz Analysis software: SPM Manager Version 4.36.10 <Preparation of measurement samples> Measurement samples were prepared in the following order of (1) to (4). (1) Attach carbon tape to the sample stage and peel off the release paper with tweezers. (2) Hold the edge of the sample with tweezers and cut it with scissors. Cut it into a size of 8 mm × 8 mm smaller than the carbon tape to prepare the sample. (3) Blow the front and back of the sample with a blower to remove foreign objects. (4) With the sample surface (measurement surface) facing up, attach carbon tape to the back surface of the sample to prepare the measurement sample. <Arithmetic mean roughness Ra> The arithmetic mean roughness Ra is obtained in micrometers (μm) as the value calculated by the following formula according to JIS B0031 (1994). From the surface roughness curve of the obtained measurement sample, only a reference length (l) is extracted in the direction of the mean line. With the X-axis in the direction of the mean line of this extracted part and the Y-axis in the direction of the vertical magnification, when the roughness curve is represented as y = f(x).

Equation

number

[0158] (Hardness of the low refractive index layer surface: Measurement of indentation hardness (MPa)) The following measurements were taken using the "TI950 TriboIndenter" manufactured by HYSITRON in displacement control mode. In the low refractive index layer, a Berkovich indenter (triangular pyramidal, diamond, 115-degree edge angle) was pressed in at a loading rate of 10 nm / s to a depth of 30 nm or 300 nm. After holding it for a certain period of time to relax residual stress, the load was removed to obtain a load-displacement curve, and the indentation hardness was then automatically calculated by the device. Calculation Overview: Using the unloading curve, the contact depth (the depth to which the sample is in contact with the indenter) is calculated, and the contact projected area (A(nm)) is calculated from that contact depth. 2 The area is determined, and using this area and the maximum load after relaxation (Pmax (μN)), the indentation hardness is automatically calculated by the device using Pmax / A. In order to obtain stable measurement results, the sample surface was observed using a microscope at a magnification of 50 to 500 times, and measurements were taken by selecting the flattest possible area without any unusual defects, while avoiding areas with extremely uneven structures.

[0159] <Preparation of measurement samples> An optical laminate cut to a size of 20 mm x 20 mm was fixed to a commercially available microscope slide with the low refractive index layer facing upwards, using adhesive resin (product name "Aron Alpha (registered trademark) General Use," manufactured by Toagosei Co., Ltd.). Specifically, the adhesive resin was dropped onto the center of microscope slide 1 (product name "Slide Glass (Cut Type) 1-9645-11," manufactured by AS ONE Corporation). At this time, only one drop was dropped so as not to spread the adhesive resin and so as not to spill out from the optical laminate when it was spread as described later. Subsequently, the optical laminate cut to the above size was placed in contact with the glass slide so that the low refractive index layer side was facing upwards and the adhesive resin was positioned in the center of the optical laminate. The adhesive resin was then spread between the glass slide 1 and the optical laminate to temporarily bond them together. Then, another new slide glass 2 was placed on top of the optical laminate to obtain a laminate of slide glass 1 / adhesive resin / optical laminate / slide glass 2. Next, a weight of 30g to 50g was placed on slide glass 2, and the sample was left at room temperature for 12 hours. After that, the weight and slide glass 2 were removed, and this was used as the measurement sample. The obtained measurement samples were then fixed to the measurement stage of a HYSITRON "TI950 TriboIndenter" which was installed parallel to the vibration isolation table. Indentation hardness is determined by measuring five arbitrary points near the center of the low refractive index layer surface of the sample (the region where the adhesive resin is present), and taking the arithmetic mean of the hardness of the five points obtained. However, the five points to be measured were selected from the flattest possible areas, avoiding areas with extremely convex or extremely concave structures, by observing the low refractive index layer with a microscope at a magnification of 50x to 500x.

[0160] <Indentation hardness measurement with 30nm indentation> The measurement conditions for hardness when the indenter is pressed in 30 nm are as follows: Indenter used: Berkovich indenter (triangular pyramid) Measurement conditions: Displacement control method Displacement control mode Maximum displacement: 30nm Time to reach maximum displacement: 3 seconds Holding time at maximum displacement: 5 seconds Unloading time at maximum displacement: 3 seconds Test score: 5 points Temperature at time of measurement: 25℃ Relative humidity at time of measurement: 50% <Indentation hardness measurement with 300nm indentation> The measurement conditions for hardness when the indenter is pressed in 300 nm are as follows: Indenter used: Berkovich indenter (triangular pyramid) Measurement conditions: Displacement control method Displacement control mode. Maximum displacement: 300 nm Time to reach maximum displacement: 30 seconds Holding time at maximum displacement: 5 seconds Unloading time at maximum displacement: 30 seconds Test score: 5 points Temperature at time of measurement: 25℃ Relative humidity at time of measurement: 50%

[0161] (Measurement of water contact angle) The contact angle of pure water was measured using the "Drop Master 300" solid-liquid interface analyzer manufactured by Kyowa Interface Science Co., Ltd. 1.0 μL of pure water was dropped onto the low refractive index layer surface of an optical laminate. One second after the droplet landed, the contact angle was calculated using the θ / 2 method, based on the angle of the line connecting the left and right endpoints and the vertex of the dropped droplet relative to the solid surface. The average of five measurements was used as the contact angle value.

[0162] (Scratch resistance test) The surface of the low refractive index layer of the optical laminate was treated with Bonstar #0000 steel wool (product name: BON STAR, manufactured by Bonstar Sales Co., Ltd.) at a density of 700 g / cm². 2 The material was subjected to 10 reciprocating friction cycles while applying a load, and the surface of the low refractive index layer was then visually inspected for scratches and evaluated according to the following criteria. ◎: No scratches or discoloration. ○: Slight discoloration is visible. ×: Damage and discoloration are visible.

[0163] (5° specular reflectance measurement) After applying black vinyl tape (Yamato Vinyl Tape No. 200-38-21, 38mm wide) to the side of each optical laminate opposite to the side with the low refractive index layer (the measurement side), the 5° specular reflectance (%) to the surface of the optical laminate was measured in the wavelength range of 380 to 780 nm using a UV-Vis spectrophotometer (UV-2450, manufactured by Shimadzu Corporation). (Reflectance: Luminous reflectance measurement) Using the 5° specular reflectance (%) data measured above, the luminous reflectance value, calculated using software (built into the device) that converts it to brightness perceived by the human eye, was obtained as reflectance (%). For each sample, the average of the reflectance values ​​at five locations was used as the reflectance (%) for each sample: Visual reflectance measurement results (Table 2).

[0164] [Table 2]

[0165] In an example where the Ra of the surface irregularities in any 5 μm square region of the low refractive index layer was 1.5 nm or less, the Rz was 30 nm or less, and the hardness measured by nanoindentation when an indenter was pressed 300 nm was higher than the hardness measured by nanoindentation when an indenter was pressed 30 nm, the optical laminate exhibited excellent scratch resistance and anti-reflective performance. In particular, Examples 1 and 2, in which the Ra in the microscopic field of view was 1.2 nm or less, the Rz was 25 nm or less, and the difference between the indentation hardness when the indenter was pressed to a depth of 30 nm and the indentation hardness when the indenter was pressed to a depth of 300 nm was 30 MPa or more, exhibited extremely excellent scratch resistance. On the other hand, in the case of the comparative example optical laminate in which the Ra and Rz of the surface irregularities in any 5 μm square region of the low refractive index layer fell outside the specified range, excellent scratch resistance could not be obtained. Furthermore, the optical laminate according to the second embodiment of the present invention all had a total light transmittance of 90% or more, as measured using the "HM-150" manufactured by Murakami Color Technology Laboratory Co., Ltd. in accordance with JIS K7361. The 20° gloss value measured using the GM-26PRO precision gloss meter (Murakami Color Technology Laboratory Co., Ltd.) in accordance with JIS Z 8741 was within the range of 70 to 140 and the 60° gloss value was within the range of 100 to 160. In addition, the ratio of the 20° gloss value to the 60° gloss value × 100 (%) was 65 to 85 (%). The sample size for gross measurement was 5cm x 10cm, and the measurement was taken by placing the back of the sample in close contact with the blackboard using the air suction method, and the average value of three measurements was used as the measurement value. [Industrial applicability]

[0166] The optical laminate of the present invention can be suitably applied to liquid crystal displays (LCDs), cathode ray tube displays (CRTs), plasma displays (PDPs), electroluminescent displays (organic or inorganic ELDs), micro-LED displays, field emission displays (FEDs), touch panels, electronic paper, tablet PCs, and the like. It can also be suitably used as an image display surface in foldable, bendable, or rollable image display devices and touch panels.

Claims

1. An optical laminate in which an anti-glare layer and a low refractive index layer are laminated in this order on one surface of a light-transmitting substrate, When the arithmetic mean roughness Ra and the ten-point mean roughness Rz of the surface irregularities in an arbitrary 5 μm square region of the surface of the low refractive index layer are measured, The aforementioned Ra is 4 nm or less, The Rz is 60 nm or less. The anti-glare layer contains organic fine particles and inorganic fine particles or inorganic components as anti-glare agents. The average particle size of the aforementioned organic fine particles is 0.3 to 5.0 μm. An optical laminate characterized by the following features.

2. The optical laminate according to claim 1, wherein the contact angle with water of the surface of the low refractive index layer is 102° or less.

3. An optical laminate in which an anti-glare layer and a low refractive index layer are laminated in this order on one surface of a light-transmitting substrate, When the arithmetic mean roughness Ra and the ten-point mean roughness Rz of the surface irregularities in an arbitrary 5 μm square region of the surface of the low refractive index layer are measured, The aforementioned Ra is 4 nm or less, The Rz is 60 nm or less. The low refractive index layer contains hollow silica fine particles and solid silica fine particles. An optical laminate characterized by the following features.

4. A polarizing plate comprising a polarizing element, A polarizing plate characterized by having the optical laminate according to claim 1, 2, or 3 on the surface of the polarizing element.

5. A display panel comprising an optical laminate according to claim 1, 2, or 3, or a polarizing plate according to claim 4.

6. An image display device characterized by comprising an optical laminate according to claim 1, 2, or 3, or a polarizing plate according to claim 4.

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