Optical laminate, polarizer, display panel, and image display device

Abstract

To provide an optical laminate having excellent scratch resistance while having antireflection performance.SOLUTION: An optical laminate is one in which at least an antiglare layer and a low refractive index layer are laminated in this order on one surface of a light transmitting base material. When an arithmetic average roughness Ra of unevenness and ten point average roughness Rz of unevenness in an arbitrary 5 μm square region on a surface of the low refractive index layer are measured, the Ra is 4 nm or less, and the Rz is 60 nm or less.SELECTED DRAWING: None

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] 2. Description of the Related Art Image display surfaces of image display devices such as liquid crystal displays (LCDs), cathode ray tube displays (CRTs), plasma displays (PDPs), electroluminescence displays (ELDs), and field emission displays (FEDs) are usually provided with antiglare films having an uneven surface or antireflection optical laminates having an antireflection layer on the surface in order to suppress reflections of the observer and the observer's background, etc. Such an anti-reflection optical laminate suppresses image glare and reduces reflectance by scattering or interfering with light.

[0003] One known anti-reflection optical laminate is one in which an anti-glare layer having an uneven surface is formed on the surface of a transparent substrate, and a low refractive index layer having a low refractive index is provided thereon. Such optical laminates are packed in packaging materials for transport or conveyance, but since the convex portions of the uneven shape of the antiglare layer are mainly present on the surface of the low refractive index layer, when the optical laminate comes into contact with the packaging material, it results in point contact, and it was thought that the surface of the low refractive index layer would be less likely to be scratched. However, in reality, there has been a problem in that scratches occur due to friction between the optical laminate and the packaging material. Therefore, there is a strong demand for improving the scratch resistance of optical laminates.

[0004] In conventional optical laminates, methods have been disclosed for improving the scratch resistance of the optical laminate, for example, by imparting hardness to the antiglare layer using a compound having a polymerizable unsaturated group in the antiglare layer, or by imparting hardness to the low refractive index layer by incorporating inorganic fine particles in the low refractive index layer (see, for example, Patent Document 1).

[0005] However, it is difficult to say that conventional optical laminates have sufficient scratch resistance, and there has been a demand for optical laminates with improved scratch resistance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-004979 A Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above-mentioned current situation, an object of the present invention is to provide an optical laminate having anti-reflection performance and excellent scratch resistance. [Means for solving the problem]

[0008] The present invention is an optical laminate comprising an antiglare layer and a low refractive index layer 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 unevenness in any 5 μm square area on the surface of the low refractive index layer are measured, the Ra is 4 nm or less and the Rz is 60 nm or less (hereinafter also referred to as the first present invention). The present invention also relates to an optical laminate comprising an antiglare layer and a low refractive index layer 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 unevenness in any 5 μm square region on the surface of the low refractive index layer are measured, the Ra is 1.5 nm or less and the Rz is 30 nm or less, and the hardness measured by nanoindentation when an indenter is pressed 300 nm deep is higher than the hardness measured by nanoindentation when an indenter is pressed 30 nm deep (hereinafter also referred to as the second present invention). In the following description, when there is no need to distinguish between the first optical laminate of the present invention and the second optical laminate of the present invention, they will be referred to as the "optical laminate of the present invention."

[0009] In the optical laminate of the first aspect of the present invention, the hardness of the surface of the low refractive index layer measured by nanoindentation at an indentation depth of 30 nm is preferably 440 MPa or more. In the optical layered body of the present invention, the low refractive index layer preferably contains hollow silica fine particles. The present invention also relates to a polarizing plate comprising a polarizing element, characterized in that the polarizing element is provided with the optical laminate of the present invention on a surface thereof. The present invention also relates to a display panel comprising the optical laminate of the present invention or the polarizing plate of the present invention. The present invention also relates to an image display device 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 intensively investigated methods for imparting scratch resistance to an optical laminate having an antiglare layer and a low refractive index layer on one surface of a light-transmitting substrate, and as a result, have found that the scratch resistance of the optical laminate can be improved by a method of imparting hardness to the low refractive index layer located on the surface, a method of imparting flatness to the low refractive index layer, a method of imparting slipperiness to the surface of the low refractive index layer, and a method of imparting interlayer adhesion between the low refractive index layer and the antiglare layer. The present inventors then conducted a detailed observation of the scratches that occurred on the surface of an optical laminate having a conventional antiglare layer and a low refractive index layer, and found that the scratches occurred regardless of the uneven shape. That is, there were two modes of scratches: one was that the low refractive index layer was scraped off to reduce the film thickness, which changed the interference color caused by the interference of reflected light from each layer of the optical laminate having the low refractive index layer, and the other was that the entire low refractive index layer was scraped off to cause scratches. That is, it was found that the contact between the uneven shape of the surface of the low refractive index layer having the antiglare layer as the lower layer and other surfaces was not point contact but was unexpectedly received by the entire surface. The problem of scratch resistance of an optical laminate having such an antiglare layer and a low refractive index layer is particularly prominent in the case of an optical laminate for a large screen display, in which clear images are required, so that high transparency is essential and excellent antiglare properties are also required. Furthermore, as a result of a detailed study of the mechanism by which the above-mentioned problem occurs, it was inferred that when the surface of the low refractive index layer comes into contact with a packaging material or the like, the very microscopic texture of the low refractive index layer surface (various shapes on the surface) affected by fine particles in the low refractive index layer is triggered, and when an external force is applied to the low refractive index layer due to rubbing against the surface of another article, such as a packaging material, the low refractive index layer is scraped off or the entire layer is peeled off. As a result of such investigations, it was thought that in order to improve the scratch resistance of an optical laminate having an antiglare layer and a low refractive index layer, the surface of the low refractive index layer in contact with the above-mentioned surface should be in a state where there is nothing that can cause peeling, that is, the surface should be fine and flat, so that it should be less susceptible to scratches.Then, in order to control the surface texture of the low refractive index layer, that is, the flatness, in an uneven surface, it was thought that it is necessary to examine the flatness in a microscopic field where the influence of the unevenness of the low refractive index layer surface, especially the convex parts, is small. In this way, the inventors focused on the surface of the above-mentioned low refractive index layer when viewed from a microscopic perspective and discovered that by making the surface extremely flat, it is possible to impart excellent scratch resistance, thereby completing the present invention.

[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-transmitting substrate. The low refractive index layer means a layer having a refractive index lower than the refractive index of components other than the low refractive index layer, such as the light-transmitting substrate and the antiglare layer that constitute the optical laminate of the present invention. The arithmetic mean roughness Ra, the ten-point mean roughness Rz, and the 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 are laminated in this order on one surface of a light-transmitting substrate. Furthermore, the layer structure of the optical laminate can be suitably observed in cross section at a magnification of 1,000 to 20,000 by using a STEM.

[0012] In addition, the lower the height of the irregularities on the surface of the low refractive index layer, the flatter the surface of the low refractive index layer is. The arithmetic mean roughness Ra and ten-point mean roughness Rz of the irregularities serve as indicators of the height of the irregularities on the surface of the low refractive index layer. In this way, 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 whose actual shape is unknown, it indicates the average height of all of the microscopic textures of various shapes present on the surface of the target low refractive index layer, and makes it possible to control the overall height of the texture. In addition, Rz is the average value of the highest and lowest points of the texture of the low refractive index layer surface. If only Ra is used, it is merely the result of averaging the texture of the low refractive index layer surface, so even if there are high convex parts or low concave parts, they may not be distinguished. Such unevenness may cause scratches, so that the control of the texture of the low refractive index layer surface is insufficient. Therefore, in the present invention, the maximum allowable height and maximum allowable depth are controlled by Rz in addition to the above Ra, and as a result, it is possible to control the above-mentioned sudden convex parts and concave parts.

[0013] In the first optical laminate of the present invention, the low refractive index layer has extremely excellent flatness, specifically, when the arithmetic mean roughness Ra and the ten-point mean roughness Rz of the unevenness as defined in JIS B0601 (2001) are measured in any 5 μm square region on the surface of the low refractive index layer, the Ra is 4 nm or less and the Rz is 60 nm or less. In the first optical laminate of the present invention, if the Ra exceeds 4 nm or the Rz exceeds 60 nm, the flatness of the optical laminate of the present invention is insufficient and the scratch resistance is insufficient. That is, in the optical laminate of the first invention, at least an antiglare layer and a low refractive index layer are formed in this order on a light-transmitting substrate, so that the surface of the low refractive index layer has an uneven shape derived from the antiglare layer, and the antiglare performance is ensured, but when the surface of the low refractive index layer is viewed in a microscopic field (5 μm square area), it is extremely flattened.Therefore, the optical laminate of the first invention has excellent scratch resistance. The arithmetic mean roughness (Ra) of the surface of the low refractive index layer in a microscopic field is more preferably 3 nm or less, and further preferably 2 nm or less. Furthermore, the ten-point average roughness (Rz) of the surface of the low refractive index layer in a microscopic field is more preferably 45 nm or less, and further preferably 35 nm or less. The above-mentioned excellent scratch resistance refers to, for example, a friction load of 700 g / cm using Bonstar #0000 steel wool (manufactured by Bonstar Sales Co., Ltd.). 2 This means that no scratches were observed in the abrasion resistance test involving 10 back and forth rubs. Here, as a method for controlling the uneven shape of the surface of the above-mentioned low refractive index layer, particularly the flatness within a specific region on the surface other than the convex portions, the low refractive index layer can be suitably formed by selecting a solvent for the composition for the low refractive index layer described later, drying conditions and curing conditions when applying the composition for the low refractive index layer described later to form a coating film, and selecting a leveling agent contained in the composition for the antiglare layer 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 the surface roughness parameters obtained by AFM is specified in JIS B0031 (1994), but in the case of AFM, it can be calculated as the surface average value within the scanning range (field of view area) using the software attached to the SPM-9600. Cantilever: NCH-W (Nano World) Scanning range: 5μm (field of view area 5μm×5μm) Scanning speed: 1Hz However, the AFM measurements were performed excluding areas where defects such as specific detachment or irregularities were observed. The reason why the scanning range is set to 5 μm (field of view area 5 μm×5 μm) is that in order to judge and control the texture and flatness of the low refractive index layer surface laminated on the antiglare layer surface that originally has some unevenness, the field of view area for measurement is narrowed as much as possible to reduce the influence of the unevenness of the antiglare layer. If the field of view area is wider than the above range, the measurement itself with AFM may be difficult due to defects such as bending of the measurement sample, unevenness of the antiglare layer, and environmental foreign matter. On the other hand, if the field of view area is narrower than the above range, the surface roughness of the low refractive index layer may not be properly evaluated. The analysis conditions for Ra and Rz are as follows, and the device used for the measurement is SPM-9600 (manufactured by Shimadzu Corporation). <Preparation of measurement sample> A measurement sample is 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 end of the sample with tweezers and cut it with scissors to create a sample that is 8 mm x 8 mm in size, smaller than the carbon tape. (3) Blow the front and back of the sample with a blower to remove any foreign matter. (4) Place the sample front (measurement surface) facing up and attach carbon tape to the back of the sample to prepare a measurement sample. <Arithmetic mean roughness Ra> The arithmetic mean roughness Ra is the value, in micrometers (μm), calculated by the following formula in accordance with JIS B0031 (1994), by cutting out only a reference length (l) in the direction of the mean line from the roughness curve of the surface of the measurement sample obtained, plotting the X-axis in the direction of the mean line of this cut-out portion and the Y-axis in the direction of the longitudinal magnification, and expressing the roughness curve as y = f(x).

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[0014] The low refractive index layer in the optical laminate of the first aspect of the present invention preferably has a surface hardness of 440 MPa or more, measured by nanoindentation at an indentation depth of 30 nm. By having the hardness in such a range, it is possible to suitably impart even better scratch resistance to the optical layered body of the first aspect of the present invention. The nanoindentation method is a method that can determine hardness and elastic modulus using load, displacement of the indenter from the point where the indenter contacts the sample surface, and time, which are physical quantities that can be directly measured. That is, as shown in Figure 1(a), the indentation load p when an indenter (acute indenter) is pressed into a sample, and the indentation depth (indentation depth h) when the indenter is unloaded are continuously observed in situ, and the indentation load-indentation depth curve shown in Figure 1(b) is obtained to determine hardness and elastic modulus without directly observing the indentation. However, the basic principle of this method was derived under the assumption of an elastic deformation region, so when calculating hardness, it is calculated under elastic deformation conditions in accordance with this assumption. Since it is difficult to avoid the mixing of elastic and plastic deformation during the indentation process, the surface at the time of plastic deformation is treated as the starting point of the analysis in order to separate only the contribution of elastic deformation. In other words, as shown in Figure 1 (b), the hardness is obtained 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 expresses the properties of elastic deformation of the cured resin layer made of a polymer material such as that of the present invention. In order to improve the scratch resistance, which is the objective of the present invention, it is believed that the force that pushes back the scratching force immediately after the scratched surface layer itself receives the scratching force has an effect. Since this mechanism exactly matches the mechanism of hardness by the nanoindentation method described above (the force of elastic recovery after plastic deformation), among various indentation hardness test methods, evaluation by the nanoindentation method was selected as the most suitable for the present invention. As mentioned above, it is considered essential to improve the flatness and the texture of the low refractive index layer surface in order to improve scratch resistance. 2 ~500g / cm 2 This level of abrasion resistance is achieved, and is preferably used for fixed TV monitor displays for home use. On the other hand, displays in recent years are often used for digital signage at stations and airports, and there are more and more situations where they are rubbed by foreign objects such as dust, people, bags, and other objects, so a higher level of abrasion resistance, for example a load of 600g / cm, is required. 2 In some cases, the above scratch resistance is preferred. In such cases, it has been found to be effective to improve the hardness, which is involved in the elastic deformation and elastic recovery of the low refractive index layer itself, which is the surface layer that receives the rubbing force, as well as the flatness. The indentation depth is 30 nm because it is necessary to measure the hardness of the low refractive index layer, which is affected by the elastic deformation force of the low refractive index layer itself. This depth also allows for stable measurement, and is hardly affected by the underlying layer, such as the antiglare layer. The hardness of the low refractive index layer surface measured by the nanoindentation method under the condition of an indentation depth of 30 nm is more preferably 500 MPa or more, and even more preferably 600 MPa or more. The upper limit of the hardness of the low refractive index layer surface measured under the condition of an indentation depth of 30 nm is preferably 4000 MPa, more preferably 2000 MPa, and even more preferably 1600 MPa. If it exceeds 4000 MPa, microcracks are likely to occur due to the hardness difference with the antiglare layer, which is the base, and therefore the adhesion between the low refractive index layer and the antiglare layer is reduced, which may cause peeling. In this specification, the hardness measured by the nanoindentation method is measured in a displacement control mode using a "TI950 TriboIndenter" manufactured by HYSITRON Corporation. Specifically, in the low refractive index layer, a Berkovich indenter (triangular pyramid, made of diamond, with a 115 degree edge angle) as shown in Figure 2 is pressed 30 nm at a loading rate of 10 nm / s, held for a certain period of time to relax the residual stress, and then unloaded to obtain a load-displacement curve, after which the indentation hardness is automatically calculated by the device. Calculation overview: Using the unloading curve, the depth at which the sample is in contact with the indenter (contact depth) is calculated, and the contact projected area (A (nm 2 ) is obtained, and the indentation hardness is automatically calculated using this area and the maximum load after relaxation (Pmax (μN)) as Pmax / A. Note that the automatic calculation uses analytical methods such as those proposed by Oliver-Pharr et al. In order to obtain stable measurement results, the sample surface was observed using a microscope at a magnification of 50 to 500 times, and the measurement was performed on a part that was as flat as possible without any particular defects, avoiding any part with an extremely uneven structure. The indentation depth of the indenter was selected to be 30 nm, which allows stable measurement of hardness by the nanoindentation method, and the measurement of hardness by the nanoindentation method was performed in an environment of 25°C ± 5°C and a relative humidity of 30% to 70%.

[0015] The measurement sample for the nanoindentation method can be prepared, for example, by the following method. The optical laminate cut into a size of 20 mm x 20 mm is fixed to a commercially available slide glass with the low refractive index layer side facing up via an adhesive resin (product name "Aron Alpha (registered trademark) general use", manufactured by Toa Gosei Co., Ltd.). Specifically, the adhesive resin is dripped onto the center of a slide glass 1 (product name "Slide glass (cut type) 1-9645-11", manufactured by AS ONE Corporation). At this time, the adhesive resin is not spread out, and only one drop is dripped so that the adhesive resin does not protrude from the optical laminate when it is pressed out as described below. Then, the optical laminate cut to the above size is brought into contact with the glass slide so that the low refractive index layer side is on top and the adhesive resin is located in the center of the optical laminate, and the adhesive resin is spread between the glass slide 1 and the optical laminate to temporarily bond them. Then, another new slide glass 2 is placed on the optical laminate to obtain a laminate of slide glass 1 / adhesive resin / optical laminate / slide glass 2. Next, a weight of 30 g to 50 g is placed on the glass slide 2, and the glass slide 2 is left in this state for 12 hours at room temperature. After that, the weight and the glass slide 2 are removed, and the resulting sample is used as a measurement sample. The four corners of the optical laminate fixed with the adhesive resin may be further fixed with tape (product name: Cellotape (registered trademark), manufactured by Nichiban Co., Ltd.).

[0016] As a specific method for measuring the hardness (indentation hardness) by the nanoindentation method using the above measurement sample, for example, the following method can be used. The measurement sample is fixed to a measurement stage of a measurement device that is placed parallel to a vibration isolation table. The fixing may be performed by fixing the four sides of the slide glass 1 with tape (product name: Cellotape (registered trademark), manufactured by Nichiban Co., Ltd.) or the like, and any method may be used as long as the measurement sample does not move. Furthermore, if the measuring device has an air suction system, it may be fixed by the air suction system. After the measurement sample is fixed on the measurement stage, the indentation hardness is measured at a position where the surface of the low refractive index layer is indented by a depth of 30 nm under the following measurement conditions. The indentation hardness is measured at any five points near the center of the surface of the low refractive index layer of the measurement sample (area where the adhesive resin is present), and the arithmetic average of the hardness values ​​obtained at the five points is determined. However, the five arbitrary measurement points are selected by observing the low refractive index layer using a microscope at a magnification of 50x to 500x, and selecting points from areas that are as flat as possible while avoiding areas with extremely convex structures and areas with extremely concave structures.

[0017] As specific conditions for measuring the hardness when the indenter is pressed 30 nm, for example, the following conditions are preferably used. Indenter used: Berkovich indenter (triangular pyramid) Measurement conditions: Displacement control method Displacement control mode Maximum displacement: 30 nm Time to reach maximum displacement: 3 seconds Hold time at maximum displacement: 5 seconds Time to unload from maximum displacement: 3 seconds Test score: 5 points (the arithmetic mean value is the measurement result) Measurement temperature: 25℃ Relative humidity during measurement: 50%

[0018] In the second optical laminate of the present invention, the low refractive index layer has extremely excellent flatness, and specifically, when the arithmetic mean roughness Ra and the ten-point mean roughness Rz of the unevenness defined in JIS B0601 (1992) are measured in any 5 μm square region on the surface of the low refractive index layer, the Ra is 1.5 nm or less, and the Rz is 30 nm or less. That is, in the second optical laminate of the present invention, at least an antiglare layer and a low refractive index layer are formed in this order on a light-transmitting substrate, so that an uneven shape originating from the antiglare layer is formed on the surface of the low refractive index layer, thereby ensuring antiglare performance, but when the surface of the low refractive index layer is viewed in a microscopic field (5 μm square area), it appears extremely flat. In the second optical laminate of the present invention, the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) ranges are satisfied, and further, the hardness of the low refractive index layer surface measured by a nanoindentation method satisfies a specific relationship, so that the optical laminate can have preferable flatness and excellent scratch resistance. In the optical laminate of the second aspect 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. In the optical laminate of the second aspect 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 700 g / cm using Bonstar #0000 steel wool (manufactured by Bonstar Sales Co., Ltd.). 2 This means that no scratches were observed in the abrasion resistance test involving 10 back and forth rubs. Here, the uneven shape of the surface of the above-mentioned low refractive index layer in the second optical laminate of the present invention can be suitably formed by controlling, for example, the selection of a solvent for the composition for the low refractive index layer described later, the drying conditions and curing conditions when applying the composition for the low refractive index layer described later to form a coating film, and the selection of a leveling agent contained in the composition for the antiglare layer described later. In this specification, the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the surface of the above-mentioned low refractive index layer in the optical laminate of the second invention were measured and calculated under the following conditions using an AFM: SPM-9600 (manufactured by Shimadzu Corporation). The definition of the surface roughness parameters obtained by AFM is specified in JIS B0031 (1994), but in the case of AFM, it can be calculated as the surface average value within the scanning range (field of view area) using the software attached to the SPM-9600. Cantilever: NCH-W (Nano World) Scanning range: 5μm (field of view area 5μm×5μm) Scanning speed: 1Hz However, the AFM measurements were performed excluding areas where defects such as specific detachment or irregularities were observed. The reason why the scanning range is set to 5 μm (field of view area 5 μm×5 μm) is that in order to judge and control the texture and flatness of the low refractive index layer surface laminated on the antiglare layer surface that originally has some unevenness, the field of view area for measurement is narrowed as much as possible to reduce the influence of the unevenness of the antiglare layer. If the field of view area is wider than the above range, the measurement itself with AFM may be difficult due to defects such as bending of the measurement sample, unevenness of the antiglare layer, and environmental foreign matter. On the other hand, if the field of view area is narrower than the above range, the surface roughness of the low refractive index layer may not be properly evaluated. The analysis conditions for Ra and Rz are as follows, and the device used for the measurement is SPM-9600 (manufactured by Shimadzu Corporation). <Preparation of measurement sample> A measurement sample is 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 end of the sample with tweezers and cut it with scissors to create a sample that is 8 mm x 8 mm in size, smaller than the carbon tape. (3) Blow the front and back of the sample with a blower to remove any foreign matter. (4) Place the sample front (measurement surface) facing up and attach carbon tape to the back of the sample to prepare a measurement sample. <Arithmetic mean roughness Ra> The arithmetic mean roughness Ra is the value, in micrometers (μm), calculated by the following formula in accordance with JIS B0031 (1994), by cutting out only a reference length (l) in the direction of the mean line from the roughness curve of the surface of the measurement sample obtained, plotting the X-axis in the direction of the mean line of this cut-out portion and the Y-axis in the direction of the longitudinal magnification, and expressing the roughness curve as y = f(x).

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[0019] In the second optical laminate of the present invention, the low refractive index layer is an optical laminate characterized in that the hardness measured by a nanoindentation method when an indenter is pressed 300 nm is higher than the hardness measured by the nanoindentation method when an indenter is pressed 30 nm. By having the hardness in such a range, excellent scratch resistance can be suitably imparted to the optical layered body of the second present invention. The nanoindentation method is a method that can determine hardness and elastic modulus using load, displacement of the indenter from the point where the indenter contacts the sample surface, and time, which are physical quantities that can be directly measured. That is, as shown in Figure 1(a), the indentation load p when an indenter (acute indenter) is pressed into a sample, and the indentation depth (indentation depth h) when the indenter is unloaded are continuously observed in situ, and the indentation load-indentation depth curve shown in Figure 1(b) is obtained to determine hardness and elastic modulus without directly observing the indentation. However, the basic principle of this method was derived under the assumption of an elastic deformation region, so when calculating hardness, it is calculated under elastic deformation conditions in accordance with this assumption. Since it is difficult to avoid the mixing of elastic and plastic deformation during the indentation process, the surface at the time of plastic deformation is treated as the starting point of the analysis in order to separate only the contribution of elastic deformation. In other words, as shown in Figure 1 (b), the hardness is obtained 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 expresses the properties of elastic deformation of the cured resin layer made of a polymer material such as that of the present invention. In order to improve the scratch resistance, which is the objective of the present invention, it is believed that the force that pushes back the scratching force immediately after the scratched surface layer itself receives the scratching force has an effect. Since this mechanism exactly matches the mechanism of hardness by the nanoindentation method described above (the force of elastic recovery after plastic deformation), among various indentation hardness test methods, evaluation by the nanoindentation method was selected as the most suitable for the present invention. As mentioned above, it is considered essential to improve the flatness and the texture of the low refractive index layer surface in order to improve scratch resistance. By achieving extremely flatness, good texture, and the above-mentioned balanced hardness (nanoindentation hardness), a load of 700 g / cm 2 The above excellent scratch resistance can be imparted. The hardness when the indenter is pressed 30 nm is a hardness that involves the physical properties of only the low refractive index layer, such as elastic deformation and elastic recovery force. On the other hand, the hardness when the indenter is pressed 300 nm is a hardness at a depth of 200 nm more than the low refractive index layer, which is about 100 nm thick, and for example, if the base of the low refractive index layer is an antiglare layer, it is a hardness that involves the physical properties of both the antiglare layer and the low refractive index layer. Originally, the low refractive index layer is strongly related to the scratch resistance, but as the load increases, the antiglare layer, which is the underlying layer, also becomes more related. Note that the underlying layer in this case is not limited to a single layer that is directly the underlying layer of the low refractive index layer, but may be the entire multiple layers that are located below the low refractive index layer. The reason why the above-mentioned combination of flatness and hardness (nanoindentation hardness) balance is effective for high scratch resistance is believed to be as follows. When the hardness of the underlayer / low refractive index layer, such as the anti-glare layer / low refractive index layer, is greater than that of the low refractive index layer, the state of elastic properties of the laminate achieved is a state in which it can exert a physical property of pushing back the force when rubbed, and an elastic recovery force, and if there is an extremely flat surface, it can push back the rubbing force even better and continue to slide, and as a result, it is thought that it is possible to maintain the original state without scratches. On the other hand, when the hardness of the low refractive index layer is greater than that of the underlayer / low refractive index layer, the force of pushing back the rubbing force is weakened, making it difficult to achieve the above-mentioned state, and the low refractive index layer's hardness is excessively large, so that it is prone to cracking and the adhesion to the underlayer may be weakened. In the second optical laminate of the present invention, the hardness measured by the nanoindentation method when the indenter is pressed 300 nm has a preferred lower limit of 490 MPa and a preferred upper limit of 580 MPa, a more preferred lower limit of 510 MPa and a more preferred upper limit of 560 MPa. In addition, in the second optical laminate of the present invention, the hardness measured by the nanoindentation method when an indenter is pressed 30 nm is preferably 470 MPa in lower limit, 560 MPa in upper limit, more preferably 490 MPa in lower limit, and more preferably 540 MPa in upper limit. In this specification, the hardness measured by the nanoindentation method is measured in a displacement control mode using a "TI950 TriboIndenter" manufactured by HYSITRON Corporation. Specifically, in the low refractive index layer, a Berkovich indenter (triangular pyramid, made of diamond, with a 115 degree edge angle) as shown in Figure 2 is pressed 30 nm or 300 nm at a loading rate of 10 nm / s, held for a certain period of time to relax the residual stress, and then unloaded to obtain a load-displacement curve, after which the indentation hardness is automatically calculated by the device. Calculation overview: Using the unloading curve, the depth at which the sample is in contact with the indenter (contact depth) is calculated, and the contact projected area (A (nm 2) is obtained, and the indentation hardness is automatically calculated using this area and the maximum load after relaxation (Pmax (μN)) as Pmax / A. Note that the automatic calculation uses analytical methods such as those proposed by Oliver-Pharr et al. In order to obtain stable measurement results, the sample surface was observed using a microscope at a magnification of 50 to 500 times, and the measurement was performed on a part that was as flat as possible without any particular defects, avoiding any part with an extremely uneven structure. The indentation depth of the indenter was selected to be 30 nm or 300 nm, which allows stable measurement of hardness by the nanoindentation method, and the measurement of hardness by the nanoindentation method was performed in an environment of 25°C ± 5°C and a relative humidity of 30% to 70%.

[0020] The measurement sample for the nanoindentation method can be prepared, for example, by the following method. The optical laminate cut into a size of 20 mm x 20 mm is fixed to a commercially available slide glass with the low refractive index layer side facing up via an adhesive resin (product name "Aron Alpha (registered trademark) general use", manufactured by Toa Gosei Co., Ltd.). Specifically, the adhesive resin is dripped onto the center of a slide glass 1 (product name "Slide glass (cut type) 1-9645-11", manufactured by AS ONE Corporation). At this time, the adhesive resin is not spread out, and only one drop is dripped so that the adhesive resin does not protrude from the optical laminate when it is pressed out as described below. Then, the optical laminate cut to the above size is brought into contact with the glass slide so that the low refractive index layer side is on top and the adhesive resin is located in the center of the optical laminate, and the adhesive resin is spread between the glass slide 1 and the optical laminate to temporarily bond them. Then, another new slide glass 2 is placed on the optical laminate to obtain a laminate of slide glass 1 / adhesive resin / optical laminate / slide glass 2. Next, a weight of 30 g to 50 g is placed on the glass slide 2, and the glass slide 2 is left in this state for 12 hours at room temperature. After that, the weight and the glass slide 2 are removed, and the resulting sample is used as a measurement sample. The four corners of the optical laminate fixed with the adhesive resin may be further fixed with tape (product name: Cellotape (registered trademark), manufactured by Nichiban Co., Ltd.).

[0021] As a specific method for measuring the hardness (indentation hardness) by the nanoindentation method using the above measurement sample, for example, the following method can be used. The measurement sample is fixed to a measurement stage of a measurement device that is placed parallel to a vibration isolation table. The fixing may be performed by fixing the four sides of the slide glass 1 with tape (product name: Cellotape (registered trademark), manufactured by Nichiban Co., Ltd.) or the like, and any method may be used as long as the measurement sample does not move. Furthermore, if the measuring device has an air suction system, it may be fixed by the air suction system. After the measurement sample is fixed on the measurement stage, the indentation hardness is measured at a position where the surface of the low refractive index layer is indented by a depth of 30 nm or 300 nm under the following measurement conditions. The indentation hardness is measured at any five points near the center of the surface of the low refractive index layer of the measurement sample (area where the adhesive resin is present), and the arithmetic average of the hardness values ​​obtained at the five points is determined. However, the five arbitrary measurement points are selected by observing the low refractive index layer using a microscope at a magnification of 50x to 500x, and selecting points from areas that are as flat as possible while avoiding areas with extremely convex structures and areas with extremely concave structures.

[0022] As specific conditions for measuring the hardness when the indenter is pressed 30 nm, for example, the following conditions are preferably used. Indenter used: Berkovich indenter (triangular pyramid, made of diamond, 115 degree cone angle) Measurement conditions: Displacement control method Displacement control mode Maximum displacement: 30 nm Time to reach maximum displacement: 3 seconds Hold time at maximum displacement: 5 seconds Time to unload from maximum displacement: 3 seconds Test score: 5 points (the arithmetic mean value is the measurement result) Measurement temperature: 25℃ Relative humidity during measurement: 50% As specific conditions for measuring the hardness when the indenter is pressed 300 nm, for example, the following conditions are preferably used. 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 Hold time at maximum displacement: 5 seconds Unloading time at maximum displacement: 30 seconds Test score: 5 points (the arithmetic mean value is the measurement result) Measurement temperature: 25℃ Relative humidity during measurement: 50%

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

[0024] The low refractive index layer preferably contains hollow silica fine particles. The hollow silica fine particles serve to lower the refractive index of the low refractive index layer while maintaining its layer strength. In this specification, the term "hollow silica fine particles" refers to silica fine particles having a structure in which gas is filled inside, and the refractive index of the silica fine particles is reduced in inverse proportion to the occupancy rate of the gas compared to the inherent refractive index of the silica fine particles.

[0025] Specific examples of the hollow silica fine particles are not particularly limited, and for example, preferred examples include silica fine particles prepared using the technology disclosed in JP-A-2001-233611. Hollow silica fine particles are easy to manufacture and have high hardness themselves, so when they are mixed with a binder component, etc., described below, to form a low refractive index layer, the layer strength is improved and the refractive index can be adjusted to be low.

[0026] In the optical laminate of the present invention, the hollow silica fine particles have an average particle diameter of 45 to 65 nm. If it is less than 45 nm, the low refractive index layer cannot be sufficiently reduced in refractive index, while if it is more than 65 nm, the amount of protrusion from the surface of the low refractive index layer increases, and the low refractive index layer with the extremely high smoothness described above cannot be obtained. The average particle diameter of the hollow silica fine particles is preferably 47 nm in lower limit and 60 nm in upper limit, and within this range, the smoothness of the low refractive index layer can be maintained and good appearance can be obtained. The average particle diameter of the hollow silica microparticles means the average particle diameter of the hollow silica microparticles in the low refractive index layer, and is calculated as the average value by observing a cross section of the low refractive index layer in the thickness direction using an SEM, TEM, STEM, etc., randomly selecting 30 single-particle hollow silica microparticles, measuring the particle diameters of the cross section. 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 "30 kV", the emission current to "10 μA", the probe current to "Norm", the focus mode to "UHR", the condenser lens 1 to "5.0", the WD to "8 mm", and the tilt to "0°", 20 images are taken of any location on the cross section in the thickness direction of the low refractive index layer at 10,000 to 200,000 magnifications, and then the maximum diameter of 30 hollow silica microparticles is measured on the imaging screen using software provided with the STEM, and the arithmetic mean value is calculated.

[0027] In the optical laminate of the present invention, the hollow silica fine particles preferably have an average particle diameter of 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 reduced, and the antireflection performance of the optical laminate of the present invention may be poor. On the other hand, if it is 100% or more, fine unevenness caused by the hollow silica fine particles is formed on the surface of the low refractive index layer, resulting in insufficient control of the texture, and the low refractive index layer may not have sufficient flatness in a certain region, and the haze of the optical laminate of the present invention may be deteriorated. The average particle diameter of the hollow silica fine particles is preferably 70% or more and 80% or more of the thickness of the low refractive index layer. When the average particle diameter of the hollow silica fine particles is within this range, the effects of the present invention can be more favorably achieved.

[0028] The hollow silica fine particles preferably have a shell thickness of 5 to 12 nm. If the thickness is less than 5 nm, the strength of the hollow silica fine particles may be insufficient, and if the thickness exceeds 12 nm, the refractive index of the low refractive index layer may not be sufficiently reduced. The shell thickness is more preferably 6 nm in lower limit and 10 nm in upper limit. The shell means the outer shell made of silica excluding the gas present in the center of the hollow silica fine particles, and the shell thickness 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 appropriately adjusted depending on the state of the hollow silica fine particles in the low refractive index layer described later, but is preferably 50 to 200 parts by mass relative to 100 parts by mass of the binder resin (solid content) described later. If it is less than 50 parts by mass, the content of the hollow silica fine particles is small, so that the refractive index of the low refractive index layer is not sufficiently low, and the anti-reflection 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 the hollow silica fine particles is not observed, 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 preferably contains solid silica fine particles. In this specification, "solid silica microparticles" refers to silica microparticles that are different from the hollow silica microparticles described above, that are not filled with gas inside, and have the inherent refractive index of silica microparticles.The solid silica microparticles described above may be any of amorphous wet silica synthesized in liquid, dry silica produced mainly by burning silicon tetrachloride, etc.

[0031] The solid silica fine particles preferably have an average particle diameter of 8 to 50 nm. If the average particle diameter is less than 8 nm, the hardness of the low refractive index layer surface may not increase, whereas if the average particle diameter exceeds 50 nm, the arithmetic mean roughness Ra and Rz measured in any 5 μm square area on the surface of the low refractive index layer may increase. A more preferred lower limit of the average particle size of the solid silica fine particles is 10 nm, and a more preferred upper limit is 20 nm. The average particle size of the solid silica fine particles means a value measured in the same manner as for 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 with respect to 100 parts by mass of the solid content of the binder resin described below. If the content of the solid silica microparticles 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 will be insufficient, and sufficient scratch resistance may not be imparted. If the content exceeds 100 parts by mass, it may be difficult to adjust the low reflectance, and the low refractive index layer may not have sufficient flatness. The lower limit of the content of the solid silica fine particles in the low refractive index layer is more preferably 20 parts by mass, the upper limit of which is more preferably 90 parts by mass, the even more preferably 80 parts by mass, and the particularly preferably 60 parts by mass.

[0033] Furthermore, the solid silica fine particles preferably have a functional group on the surface that is reactive to a binder resin described later, such as a functional group having an ethylenic unsaturated bond, etc. By having the reactive functional group on the surface, the hardness of the low refractive index layer becomes excellent.

[0034] In the optical layered body of the present invention, the low refractive index layer may contain an additive within a range that does not impair the above-mentioned hardness. The additives are not particularly limited, and examples thereof include fluorine-based compounds, silicone-based compounds, and silicone-fluorine atom-containing compounds. These additives may be used alone or in combination of two or more. For example, materials that are compatible with the additives contained in the undercoat layer on which the low refractive index layer is laminated may be appropriately selected from the above compounds and combined. By including the above-mentioned fluorine-based compound, silicone-based compound, and silicone-fluorine atom-containing compound in the low refractive index layer, even if the low refractive index layer has an extremely excellent smoothness on the surface in a specific range region of the surface other than the convex portion as described above, the optical laminate of the present invention has excellent antiglare properties and unevenness (especially the convex portion), so that it has excellent blocking resistance. In the optical laminate of the present invention, it is presumed that the above-mentioned compound is present in high concentration on the surface of the low refractive index layer, on the air interface side. Therefore, the above-mentioned additive also functions as an antifouling agent. Therefore, the optical laminate of the present invention also has excellent antifouling performance.

[0035] The silicone-based compound is not particularly limited, and may be, for example, an organic silicone. The organic silicone is not particularly limited, but preferably has a reactive functional group in the molecule. By having the reactive functional group, the organic silicone reacts with the binder component described later, and can be suitably prevented from falling off from the low refractive index layer. Examples of organic silicones having the reactive functional group include (poly)dimethylsiloxane, (poly)diethylsiloxane, (poly)diphenylsiloxane, (poly)methylphenylsiloxane, alkyl-modified (poly)dimethylsiloxane, azo-group-containing (poly)dimethylsiloxane, dimethylsilicone, phenylmethylsilicone, 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, polyether-modified silicone, etc. Among them, those having a dimethylsiloxane structure are preferred because they are less likely to cause the problem of bleeding out from the low refractive index layer.

[0036] The content of the organic silicone is appropriately determined depending on the anti-blocking performance and anti-staining performance of the low refractive index layer, but is preferably 1 to 10 parts by mass relative to 100 parts by mass of the hollow silica fine particles and the binder component described below. If it is less than 1 part by mass, the low refractive index layer to be formed may not be able to have sufficient anti-blocking performance and anti-staining performance, and if it exceeds 10 parts by mass, the added organic silicone may bleed out from the low refractive index layer. In addition, the effect of adding the organic silicone is not seen, the manufacturing cost increases, the hardness and appearance of the obtained low refractive index layer are reduced, and further, it may cause an increase in reflectance. The more preferable lower limit of the content of the organic silicone is 2 parts by mass, and the more preferable upper limit is 8 parts by mass.

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

[0038] As the compound containing the reactive functional group and a fluorine atom, for example, a wide variety of reactive fluorine compounds, particularly fluorine-containing monomers having an ethylenically unsaturated bond, can be used. More specific examples include fluoroolefins (e.g., fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluorobutadiene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.). Further 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)acrylic acid ester compounds having a fluoroalkyl group, fluorocycloalkyl group or fluoroalkylene group having 1 to 14 carbon atoms and having at least three fluorine atoms in the molecule, and at least two (meth)acryloyloxy groups. Further examples include fluorinated polymers and oligomers having a fluorinated alkylene group in the main chain, and fluorinated polymers and oligomers having a fluorinated alkylene group or a fluorinated alkyl group in the main chain and side chain. Among these, fluorinated polymers having a fluorinated alkylene group or a fluorinated alkyl group in the main chain and side chain are particularly preferably used because they are less likely to cause the problem of bleeding out from the low refractive index layer.

[0039] Examples of the compound containing the reactive functional group as well as a fluorine atom and a silicon atom include a silicone-containing vinylidene fluoride copolymer obtained by reacting the reactive fluorine compound with an organosilicon having the reactive functional group in the molecule, and a fluorine-modified organosilicon compound.

[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, so long as the effect of the present invention is not impaired. When the low refractive index layer further contains an antifouling agent, the optical layered body of the present invention has more excellent antifouling performance.

[0041] The low refractive index layer preferably contains a binder component. The binder component includes an ionizing radiation curable resin, and in the present invention, a (meth)acrylic resin is particularly preferably used. In this specification, "(meth)acrylic" means acrylic or methacrylic. The (meth)acrylic resin includes a polymer or copolymer of a (meth)acrylic monomer. The (meth)acrylic monomer is not particularly limited, and suitable examples thereof include 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. In addition, these (meth)acrylate monomers may have a part of their molecular skeleton modified, and those modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, etc. may also be used. These (meth)acrylic monomers may be used alone or in combination of two or more. These (meth)acrylic monomers satisfy the refractive index range described below and have excellent curing reactivity, and can improve the hardness of the obtained low refractive index layer.

[0042] The (meth)acrylic monomer preferably has a refractive index of 1.47 to 1.53. It is practically impossible to make the refractive index less than 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] The (meth)acrylic monomer preferably has a weight average molecular weight of 250 to 1000. If it is less than 250, the number of functional groups is small, so that the hardness of the obtained low refractive index layer may decrease. If it exceeds 1000, the functional group equivalent (number of functional groups / molecular weight) generally becomes small, so that the crosslink density becomes low and a low refractive index layer with sufficient hardness may not be obtained. The weight average molecular weight of the (meth)acrylic monomer can be determined by gel permeation chromatography (GPC) in terms of polystyrene. Tetrahydrofuran or chloroform can be used as the solvent for the GPC mobile phase. The measurement column can be a combination of commercially available columns for tetrahydrofuran or chloroform. Examples of the commercially available columns include Shodex GPC KF-801 and GPC-KF800D (both trade names, manufactured by Showa Denko K.K.). As the detector, an RI (differential refractive index) detector and a UV detector can be used. Using such a solvent, column, and detector, the weight average molecular weight can be appropriately measured by a GPC system such as Shodex GPC-101 (manufactured by Showa Denko K.K.).

[0044] In the optical laminate of the present invention, the change rate of the water contact angle of the surface of the low refractive index layer before and after the saponification treatment is preferably 15% or less. If it exceeds 15%, the organic silicone on the surface of the low refractive index layer will fall off, and the blocking resistance and contamination resistance of the optical laminate of the present invention may become insufficient. The upper limit of the change rate of the water contact angle of the surface of the low refractive index layer is more preferably 10%, and even more preferably 5%. The rate of change in the water contact angle on the surface of the low refractive index layer before and after the above-mentioned saponification treatment can be measured using a contact angle meter before and after the saponification treatment of the low refractive index layer and calculated as {(measured value before - measured value after) / measured value before} x 100.

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

[0046] The thickness (nm) 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. It is preferable that the above conditions are satisfied.

[0047] In the present invention, the low refractive index layer is represented by the following formula (II): 120 <n A d A <145 (II) It is preferable in terms of achieving low reflectance to satisfy the above condition.

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

[0049] The composition for the low refractive index layer may further contain a solvent. The solvent is not particularly limited, and examples thereof include 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. Of these, methyl isobutyl ketone, methyl ethyl ketone, isopropyl alcohol (IPA), n-butanol, s-butanol, t-butanol, PGME, and PGMEA are preferred.

[0050] Furthermore, the composition for a low refractive index layer may contain other components as necessary. Examples of the other components include 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] When the composition for the low refractive index layer contains a resin system having a radically polymerizable unsaturated group, examples of the photopolymerization initiator include acetophenones (for example, 1-hydroxycyclohexylphenylketone commercially available under the trade name Irgacure 184 (manufactured by BASF)), benzophenones, thioxanthones, benzoin, benzoin methyl ether, etc., which may be used alone or in combination of two or more kinds. In addition, when the composition for the low refractive index layer contains a resin system having a cationically polymerizable functional group, examples of the photopolymerization initiator include aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene compounds, benzoin sulfonate esters, etc., which may be used alone or in combination of two or more. Specific examples of photopolymerization initiators that can be used in the present invention include 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, and DAROCUR 1173, all manufactured by Chiba Specialty Chemicals; Speedcure MBB, Speedcure PBZ, Speedcure ITX, Speedcure CTX, Speedcure EDB, Esacure ONE, Esacure KIP150, and Esacure KTO46, all manufactured by Nippon Kayaku Co., Ltd. CTX, KAYACURE BMS, KAYACURE DMBI, etc. Among these, Irgacure 369, Irgacure 127, Irgacure 907, Esacure ONE, Speedcure MBB, Speedcure PBZ, and KAYACURE DETX-S are preferred. The amount of the photopolymerization initiator added is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the solid content of the binder resin. The leveling agents, crosslinking agents, curing agents, polymerization accelerators, viscosity modifiers, antistatic agents, ultraviolet absorbers, light absorption wavelength modifiers, pigments, dyes, and other resins may be any known agents.

[0052] The viscosity of the composition for the low refractive index layer is preferably in the range of 0.5 to 5 cps (25° C.), preferably 0.7 to 3 cps (25° C.), which allows favorable coating properties to be obtained. A film with excellent anti-reflection properties for visible light can be realized, and a thin film with no coating unevenness can be formed, and further, a low refractive index layer with particularly excellent adhesion to the substrate can be formed.

[0053] The method for preparing the composition for the low refractive index layer is not particularly limited, and for example, the composition can be obtained by mixing the hollow silica fine particles, the monomer component of the binder component, the organic silicone, and the components such as an antifouling agent, a solvent, and a photopolymerization initiator that are added as necessary. The mixing can be performed using a known device such as a paint shaker, a bead mill, a kneader, or a mixer. Any known method can be used.

[0054] The low refractive index layer can be formed by applying the composition for a low refractive index layer onto an antiglare layer described later, drying the formed coating film as necessary, and curing the coating film by irradiation with ionizing radiation and / or heating. The method for applying the composition for the low refractive index layer is not particularly limited, and examples thereof include various methods such as spin coating, dipping, spraying, dye coating, bar coating, roll coating, meniscus coating, flexographic printing, screen printing, and pad coating.

[0055] The light-transmitting substrate is preferably one having smoothness, heat resistance, and excellent mechanical strength. Specific examples of materials forming the light-transmitting substrate include polyester (polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, and thermoplastic resins such as polyurethane. Preferred examples include polyester (polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, and polymethyl methacrylate (PMMA). The resin materials constituting the light-transmitting substrate may be used alone or in combination.

[0056] It is preferable to use the above-mentioned thermoplastic resin as a flexible film-like body for the light-transmitting substrate, but depending on the usage mode requiring hardening, it is also possible to use a plate of these thermoplastic resins, or a plate-like body such as a glass plate may be used.

[0057] Other examples of the light-transmitting substrate include amorphous olefin polymers (cyclo-olefin-polymers:COP) films having alicyclic structures. These are substrates using norbornene-based polymers, monocyclic cyclic olefin-based polymers, cyclic conjugated diene-based polymers, vinyl alicyclic hydrocarbon-based polymers, etc., and include, for example, Zeonex and Zeonoa (COP) manufactured by Nippon Zeon Co., Ltd., Sumilite FS-1700 manufactured by Sumitomo Bakelite Co., Ltd., Arton (modified norbornene-based resin) manufactured by JSR Co., Ltd., Apel (cyclic olefin copolymer) manufactured by Mitsui Chemicals, Inc., Topas (cyclic olefin copolymer) manufactured by Ticona, and Optretz OZ-1000 series (alicyclic acrylic resin) manufactured by Hitachi Chemical Co., Ltd. As an alternative substrate to triacetyl cellulose, the FV series (low birefringence and low photoelasticity film) manufactured by Asahi Kasei Chemicals Corporation is also preferred.

[0058] The thickness of the light-transmitting substrate is preferably 5 to 300 μm in the case of a film-like body, more preferably a lower limit of 10 μm, even more preferably a lower limit of 15 μm, and even more preferably an upper limit of 200 μm. When a thinner film is desired, the upper limit is more preferably 90 μm, particularly preferably an upper limit of 70 μm, and most preferably an upper limit of 50 μm. When the light-transmitting substrate is a plate-like body, the thickness may exceed these thicknesses. When the antiglare layer or the like is formed on the light-transmitting substrate, in order to improve adhesion, the light-transmitting substrate may be previously subjected to physical or chemical treatment such as corona discharge treatment or oxidation treatment, or may be previously coated with a coating material called an anchor agent or primer. In addition, the light-transmitting substrate for LCDs is made of triacetyl cellulose or polymethyl methacrylate, polyester, norbornene resin, or cyclic olefin resin, which are often used as the light-transmitting substrate for LCDs, and the light-transmitting substrate for OLEDs is made of polyimide film (not polyimide alone, polyamide may be mixed) in addition to the light-transmitting substrate for LCDs. In order to reduce the thickness of the display, the thickness of the light-transmitting substrate is preferably 7 to 45 μm. In order to reduce the thickness of the display, the more preferable upper limit of the thickness of the light-transmitting substrate is 30 μm, and the preferable upper limit of the thickness of the light-transmitting substrate for OLEDs is 20 μm.

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

[0060] The antiglare agent is in the form of fine particles, and the shape is not particularly limited and may be spherical, elliptical, amorphous, etc. As the antiglare agent, organic fine particles, inorganic fine particles, or inorganic components may be used, and transparent fine particles are preferred. The material of the organic fine particles is not particularly limited, and examples thereof 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, polyethylene fluoride resin, etc. Organic fine particles are preferable as a basic material for forming a base for unevenness, particularly a relatively large convex shape. The material for the inorganic fine particles is not particularly limited, and examples thereof 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, finely powdered silicic acid, calcium silicate, aluminum silicate, calcium carbonate, magnesium carbonate, finely powdered talc, titanium oxide, diatomaceous earth, smectite, kaolin clay, and the like. The material of the inorganic component is not particularly limited, and examples thereof include metal oxide sols such as silica sol and zirconia sol, aerosil, and clay-based components such as swelling clay. The inorganic fine particles and inorganic components can be used as a base for unevenness, especially convex shapes, by agglomerating alone. Furthermore, when an uneven base is created using organic fine particles, it is preferable to have inorganic fine particles and inorganic components around the organic fine particles, or to have inorganic fine particles and inorganic components exist as aggregates between organic fine particles (organic fine particles are not aggregated and are separated by a distance of 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 to improve scratch resistance. The above antiglare agents may be used alone or in combination of two or more kinds. The aggregation of the present invention includes not only a collection of fine particles in which fine particles are in close contact with each other anywhere in 360° around a certain particle, but also a collection of fine particles in which fine particles are gathered at a distance less than three times the average particle diameter of the fine particles somewhere in 360° around a certain particle. In particular, since a binder resin is present around the fine particles in the antiglare layer, it is considered that aggregates containing binder between fine particles are more likely to be formed than aggregates in which fine particles are completely in close contact with each other.

[0061] The inorganic fine particles may be conductive metal oxide fine particles. The conductive metal oxide fine particles are not particularly limited, and examples thereof include ZnO, Sb2O2, SnO2, CeO2, indium tin oxide, In2O3, Al2O3, antimony-doped tin oxide, and aluminum-doped zinc oxide. The organic fine particles, the inorganic fine particles, and the inorganic component materials may be used simultaneously, or a plurality of each may be used.

[0062] The organic fine particles or inorganic fine particles / inorganic components may have a core / shell structure. In this case, the shell part may have a polymerizable functional group introduced on the surface. The shell part may have a structure in which a polymerizable functional group is directly bonded to the core or a monomer, oligomer, or polymer having a polymerizable functional group is bonded to the core in a graft form by a chemical reaction; a structure in which a monomer, oligomer, or polymer having a polymerizable functional group is bonded to the surface of the particle part (core) in a coating form by a chemical reaction, and the like.

[0063] In order to suitably control the shape in a specific region when the low refractive index layer is laminated on the antiglare layer, it is important to suitably control the surface unevenness of the antiglare layer. As a preferred example, the antiglare layer contains one or more of the organic fine particles, inorganic fine particles, and inorganic component antiglare materials, and further contains a binder resin. In order to improve the surface texture of the low refractive index layer when the low refractive index layer is laminated on the antiglare layer, it is desirable to control the relatively large convex parts that are the base of the uneven shape of the surface of the antiglare layer, and also to have as few particle-induced convex parts as possible on the surface between the convex parts. When forming such a surface shape of the antiglare layer, if each antiglare material is used alone, it is preferable to make the thickness of the antiglare layer 1.5 times or more larger than the average particle diameter. If each antiglare material is an aggregated particle, it is preferable to make the thickness 1.5 times or more larger than the average particle diameter of the aggregate. The convex portion of the antiglare layer may be, for example, the above-mentioned organic fine particles, in which case the fine particles may exist alone, but generally, in many cases, several fine particles exist with narrow particle intervals. In other words, at the very least, when observing the surface of the antiglare layer, a portion where two or more fine particles are densely gathered is likely to form a convex portion. This is because, by making the film thickness larger than the average particle diameter, sufficient binder resin can be present on the fine particles existing alone (or fine particle aggregates smaller than the large fine particle aggregates forming the relatively large convex portions) other than the aggregate of fine particles that forms such a relatively large convex portion, so that the surface shape between the convex portions as described above is easy to control. In addition, 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 or the solid content between the solvent and the solute, as well as the drying conditions during production, etc. The binder resin and the solvent can be appropriately selected from those described below and used by mixing. In addition, the use of each antiglare material alone means that the above organic fine particles and the above inorganic fine particles / inorganic components are not mixed. On the other hand, for example, in the case of the above organic fine particles, a mixture of acrylic resin fine particles and styrene-acrylic copolymer fine particles, which are different resin materials, or a mixture of fine particles with different particle sizes is considered to be a single material. In the case where the antiglare layer contains multiple types of antiglare agents, such as the inorganic fine particles, the inorganic component, and organic fine particles, and a binder resin, the uneven surface shape may be formed by aggregates of the inorganic fine particles and the inorganic component, which will be described later, and the organic fine particles. In the antiglare layer formed by such a method, the uneven surface shape formed on the surface of the antiglare layer can be a shape that is controlled with less unevenness caused by particles on the surface between the main convex portions. This is presumably because, as will be described later, the inorganic fine particles, the inorganic components and the organic fine particles are distributed in a specific state in the antiglare layer. In this case, it is preferable that the particle size of the organic fine particles is larger than that of the inorganic fine particles / inorganic component. The inorganic fine particles and inorganic components preferably have an average particle size that is 10% or less of the average particle size of the organic fine particles. Note that the above applies when the inorganic fine particles and inorganic components are spherical or amorphous with a major axis / minor axis ratio of less than 5, but does not apply when the inorganic fine particles and inorganic components are amorphous with a major axis / minor axis ratio of 5 or more and in a layered, flaky state, and may be larger or smaller than the organic fine particles.

[0064] It is preferable that the inorganic fine particles and the inorganic components form aggregates and are contained coarsely and densely in the antiglare layer. The aggregates of the inorganic fine particles and the inorganic components are distributed coarsely and densely in the antiglare layer, which is preferable because a surface state other than the convex portions of the uneven shape is favorably formed on the surface of the antiglare layer. This surface state is because, when the low refractive index layer is laminated, it is easy to improve the flatness in any 5 μm square area of ​​the low refractive index layer surface to improve scratch resistance. The phrase "distributed sparsely and densely in the antiglare layer" means that the antiglare layer has a plurality of regions where the inorganic fine particles and aggregates of the inorganic component are densely distributed and a plurality of regions where the inorganic fine particles and aggregates of the inorganic component are sparsely distributed. In other words, the inorganic fine particles and aggregates of the inorganic component are non-uniformly dispersed in the antiglare layer. In this specification, when an arbitrary cross section of the anti-glare layer in the thickness direction is observed with an electron microscope (preferably a transmission type such as TEM or STEM, and for example, the observation conditions described above are used) at a magnification of 10,000 times, a region in which the area ratio of inorganic fine particles and aggregates of the inorganic components to an observation area of ​​2 μm square 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 in which the area ratio of inorganic fine particles and aggregates of the inorganic components to an observation area of ​​2 μm square is less than 1% is defined as a "region where inorganic fine particles and aggregates of the inorganic components are sparsely distributed." Furthermore, the regions where the inorganic fine particles and aggregates of the inorganic components are densely distributed, or the regions where the inorganic fine particles and aggregates of the inorganic components are sparsely distributed, i.e., the regions to be observed under the condition of 10,000x magnification with the electron microscope, can be selected by observing the distribution state of the inorganic fine particles in the cross section of the anti-glare layer in the thickness direction under the condition of a low magnification of, for example, about 3,000x. The distribution of such inorganic fine particles / aggregates of inorganic components can be easily determined by cross-sectional observation of the antiglare layer in the thickness direction using an electron microscope. The area ratio of the inorganic fine particles / aggregates of inorganic components can be calculated, for example, using image analysis software. An example of the image analysis software is WinRoof (trade name) manufactured by Mitani Shoji Co., Ltd. This software can be used to binarize and calculate an image of a 2 μm square area observed at a magnification of 10,000 times.

[0065] The inorganic fine particles are preferably surface-treated. By surface-treating the inorganic fine particles, the degree of distribution of the aggregates of the inorganic fine particles in the antiglare layer can be suitably controlled, and the effect of distributing the inorganic fine particles densely around the organic fine particles can be controlled within an appropriate range. In addition, the chemical resistance and saponification resistance of the inorganic fine particles themselves can be improved.

[0066] The above surface treatment is preferably a hydrophobizing treatment, and examples thereof include a method in which the inorganic fine particles are treated with a hydrophobizing agent such as a silane compound having an alkyl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group. Examples of the silane compound having an alkyl group include methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, trimethylsilanol, hexamethyldisilazane, methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, and octyltrimethoxysilane. Here, preferred materials for the inorganic fine particles include, for example, silica, alkali metal oxides, alkaline earth oxides, titanium oxide, zinc oxide, aluminum oxide, boron oxide, tin oxide, phosphorus oxide, indium tin oxide, zirconium oxide, etc., and silica fine particles are particularly versatile as the inorganic fine particles. Normally, hydroxyl groups (silanol groups) are present on the surface of silica fine particles, but the above-mentioned surface treatment reduces the number of hydroxyl groups on the surface of the silica fine particles, preventing the silica fine particles from aggregating excessively, thereby achieving the above-mentioned effects. It is also preferable to control the aggregation of the silica microparticles by adjusting the hydrophobicity of the surface of the silica microparticles depending on the type of hydrophobizing agent. For example, by lengthening the alkyl chain of the silane compound having an alkyl group, the effect of steric hindrance caused by the silane compound having the alkyl group becomes greater, and as a result, the hydrophobicity of the surface of the silica microparticles can be reduced.

[0067] In addition, the silica fine particles are preferably made of amorphous silica. When the silica fine particles are made of crystalline silica, the Lewis acidity of the silica fine particles becomes strong due to lattice defects contained in the crystal structure, and the excessive aggregation of the silica fine particles described above may not be controlled.

[0068] As such silica fine particles, for example, fumed silica is preferably used because it is easy to aggregate and form aggregates described later. Here, the fumed silica refers to amorphous silica having a particle size of 200 nm or less produced by a dry method, and is obtained by reacting a volatile compound containing silicon in a gas phase. Specifically, for example, a silicon compound, for example, a compound produced by hydrolyzing SiCl4 in a flame of oxygen and hydrogen, etc. can be mentioned. Specifically, for example, AEROSIL R805 (manufactured by Nippon Aerosil Co., Ltd.) can be mentioned.

[0069] The content of the silica fine particles is not particularly limited, but is preferably 0.1 to 5.0% by mass in the antiglare layer. If it is less than 0.1% by mass, it may not be possible to form a sufficiently dense distribution around the organic fine particles, and it may be difficult to form a surface state of the antiglare layer that is preferable for improving scratch resistance, and if it exceeds 5.0% by mass, excessive aggregates are generated, causing internal diffusion, which may result in a decrease in transparency and a problem of appearing whitish. A more preferable lower limit is 0.5% by mass, and a more preferable upper limit is 3.0% by mass.

[0070] The silica fine particles preferably have an average particle size of 1 to 100 nm. If the average particle size is less than 1 nm, a sufficiently dense distribution may not be formed around the organic fine particles, and if the average particle size exceeds 100 nm, a sufficiently dense distribution may not be formed around the organic fine particles. A more preferred lower limit is 5 nm, and a more preferred upper limit is 50 nm. The average particle size of the silica microparticles can be determined by measuring the particle sizes of 50 randomly selected microparticles by visual observation from an image of a cross-section electron microscope (transmission type such as TEM or STEM, preferably with a magnification of 10,000 to 100,000 times or more) and averaging the measured values. The average size can also be determined from the image by using image processing software (for example, WinRoof, a product name manufactured by Mitani Shoji Co., Ltd.). Either method uses a cross-section observation image, so approximately the same measurement results can be obtained.

[0071] The aggregates of the silica fine particles may form a structure in which the silica fine particles are strung together in the antiglare layer in the shape of beads (like a pearl necklace). By forming aggregates in which the silica fine particles are linked together like beads in the antiglare layer, the surface condition of the antiglare layer other than the convex portions of the surface irregularities can be favorably formed, as described below. The structure in which the silica microparticles are linked together like beads may be any structure, such as a structure in which the silica microparticles are linked together in a straight line (straight-chain structure), a structure in which multiple straight-chain structures are entangled, or a branched structure having one or more side chains formed by multiple consecutive silica microparticles in the straight-chain structure.

[0072] The aggregate of silica fine particles preferably has an average particle diameter of 100 nm to 2 μm. If it is less than 100 nm, the buffering effect of the aggregate's unevenness formation due to cure shrinkage described later may not be fully exhibited, and if it exceeds 2 μm, a dense distribution may not be formed sufficiently around the organic fine particles, and light may be diffused by the aggregate of silica fine particles, or the surface unevenness caused by the aggregate may become too large, resulting in poor light room and dark room contrast of the image display device. The more preferred lower limit of the average particle diameter of the aggregate is 200 nm, and the more preferred upper limit is 1 μm. Since the aggregate does not have a fixed shape, 2 μm and 1 μm are often the major axis of the aggregate. The average particle size of the silica microparticle aggregate is obtained by selecting a 5 μm square area containing a large number of silica microparticle aggregates from cross-sectional electron microscopy (10,000 to 20,000 times magnification), measuring the particle size of the silica microparticle aggregates in the area, and averaging the particle sizes of the top five silica microparticle aggregates excluding the largest one. The "particle size of the silica microparticle aggregate" is measured as the distance between two lines that are the maximum distance between the cross-section of the silica microparticle aggregate when the cross-section is sandwiched between any two parallel lines. The particle size of the silica microparticle aggregate may be calculated using image analysis software.

[0073] It is also preferred that the silica fine particles are densely distributed in the antiglare layer in the form of aggregates around the organic fine particles contained therein. In addition, as mentioned above, the aggregate of silica fine particles is preferably contained in the antiglare layer in a sparsely dense manner, and the antiglare layer preferably has a region in which a large number of aggregates of silica fine particles exist around the organic fine particles, and a region in which only the aggregates of silica fine particles are densely distributed.For example, the state in which the aggregates of silica fine particles are densely distributed around the organic fine particles can be easily confirmed by observing the cross section of the antiglare layer with an electron microscope. Here, when a cross-section of the anti-glare layer is observed with an electron microscope, the aggregates of silica microparticles densely distributed around the organic microparticles are observed to be densely distributed not only in a cross-section passing through the center of the organic microparticles, but also in a cross-section shifted from the center of the organic microparticles. The above-mentioned "aggregates of silica microparticles are densely distributed around the organic microparticles" means that when a cross section of the anti-glare layer in which the organic microparticles are observed in the thickness direction is observed at a magnification of 20,000 times using an electron microscope (preferably a transmission type such as TEM or STEM), the area ratio of the aggregates of silica microparticles to the area within a circumference 200 nm outside the organic microparticles and excluding the organic microparticles is 10% or more.

[0074] By containing aggregates of silica fine particles and organic fine particles in the antiglare layer, when the low refractive index layer is laminated on the antiglare layer, the surface texture of the low refractive index layer is good, and the shape can be controlled to have specific ranges of Ra and Rz, which is preferable for improving scratch resistance. It is presumed that such a shape can be achieved for the following reasons. That is, when the composition for antiglare layer is applied and dried to evaporate the solvent, if the viscosity of the binder resin is low, the binder resin is likely to follow the shape of the organic fine particles. Furthermore, if the binder resin is only a polyfunctional monomer, the volume may shrink when cured, but the organic fine particles in a polymer state do not shrink, so that only the binder resin shrinks, and for example, a relatively large convex part formed on the surface at a position corresponding to the location where two or more organic fine particles are aggregated becomes steeply inclined, and small convex parts caused by organic fine particles existing alone may also be easily formed between the relatively large convex parts that serve as the base of such uneven shape. However, because aggregates of silica fine particles are densely distributed around the organic fine particles, the viscosity of the composition for antiglare layer around the organic fine particles increases, making it difficult for the binder resin to conform to the shape of the organic fine particles when the solvent evaporates, and the binder (consisting of the binder resin and silica fine particles) in that area is less likely to shrink on hardening. Furthermore, when the silica fine particles become aggregates, they contain the binder resin and are loosely aggregated, so they also have a buffering effect against hardening shrinkage. As a result, the steep slope of the relatively large convexities formed on the surface at positions corresponding to the aggregates of several or more organic fine particles is suppressed, and since there is something with the above buffering effect around the organic particles that exist alone (or as aggregates smaller than the aggregates of fine particles that form the relatively large convexities), the spaces between the relatively large convexities, i.e., the surfaces other than the convexities, become highly flat. For this reason, it is presumed that the state of the surface other than the convex parts of the uneven shape formed on the surface of the anti-glare layer by the organic fine particles is easily controlled to be preferable. Although the above reasons have been described using silica fine particles as an example, it is considered that not only silica fine particles but also other inorganic fine particles and inorganic components are formed when used in combination with the organic fine particles, and a good surface shape of the anti-glare layer can be formed by a similar mechanism. As described above, even if an antiglare layer composition contains only organic fine particles, an antiglare layer having a suitable surface condition can be formed by controlling the viscosity of the binder resin, the film thickness, and the like. When comparing an anti-glare layer composition containing only organic fine particles with an anti-glare composition containing inorganic fine particles and / or inorganic components in addition to organic fine particles, the latter material system is superior in that it allows for the free adjustment of the composition viscosity and other factors without depending on the inherent physical properties of the binder resin itself, making it possible to design a variety of surface shapes.

[0075] In the antiglare layer, the organic fine particles and the silica fine particles are preferably spherical in shape as single particles, and when the organic fine particles and the silica fine particles are applied to an image display device, a high-contrast display image can be obtained. The above-mentioned "spherical" refers to, for example, a perfect sphere, an oval sphere, etc., and does not mean so-called amorphous.

[0076] The organic fine particles are fine particles that mainly form the surface irregularities of the antiglare 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 in the antiglare layer. In addition, since it is easy to control the refractive index difference between the organic fine particles and the binder resin, it is possible to control the antiglare properties and maintain transparency, and suppress the occurrence of whitishness.

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

[0078] The size of the organic fine particles is appropriately determined according to the thickness of the antiglare layer, and for example, the average particle diameter is preferably 0.3 to 5.0 μm. If it is less than 0.3 μm, the dispersibility of the organic fine particles may not be controlled, and if it exceeds 5.0 μm, the convex shape of the antiglare layer surface may become large, making it difficult to obtain a surface state of the antiglare layer that can improve the scratch resistance. The more preferred lower limit is 1.0 μm, and the more preferred upper limit is 3.0 μm. The average particle size of the organic fine particles is preferably 20 to 60% of the thickness of the antiglare layer. If it exceeds 60%, the organic fine particles may protrude from the surface of the coating layer, and the protrusions caused by the organic fine particles may be too large. If it is less than 20%, a sufficient protrusion shape cannot be formed on the surface of the antiglare layer, and the antiglare performance may be insufficient. The average particle size of the organic fine particles in the antiglare layer is determined as the average value of the maximum diameter of the particles in the transmission optical microscope observation of the antiglare layer. In this case, an optical laminate of about 2 cm square is fixed to a slide glass with tape or the like, and three parts considered to be homogeneous surfaces without foreign matter or scratches are observed at 200 to 500 times, and the maximum diameters of 15 particles visible in the field of view are measured and the average value is determined as the arithmetic mean value. Or, if that is not appropriate, in observing a cross section passing near the center of a particle with an electron microscope (preferably a transmission type such as TEM or STEM), 30 randomly selected diffuse particles of the same type that are observed to have roughly the same particle size are selected (the number n is increased because it is unclear which part of the particle the cross section is from), and the maximum particle size of the cross section is measured, and the value is calculated as the average value. In either case, the value can be determined from an image, so it may be calculated using image analysis software. In the case of the particle size of the particles used in the antiglare layer, the weight average diameter does not differ significantly from the diameter observed under a microscope or the like. 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 20000 times magnification, and 30 of the particles captured are selected on the imaging screen using the attached software to measure the maximum particle size, which is calculated as the arithmetic average value. Measurement conditions can be, for example, signal selection to "SE", acceleration voltage to "5 kV", emission current to "10 μA to 20 μA", SE detector to "mix", probe current to "Norm", focus mode to "UHR", condenser lens 1 to "5.0", WD to "8 mm", tilt to "30°", etc., 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] In addition, by including an inorganic component, particularly a clay-based inorganic component such as a swelling clay, in the antiglare layer, it is possible to easily adjust the surface condition of the antiglare layer other than the convex shape and convex portions.

[0080] The swelling clay may be any clay that has a cation exchange capacity and swells by taking in water between the layers of the swelling clay, and may be a natural or synthetic product (including substitution products and derivatives), or a mixture of a natural product and a synthetic product. Examples of the swelling clay include mica, synthetic mica, vermiculite, montmorillonite, iron montmorillonite, beidellite, saponite, hectorite, stevensite, nontronite, magadiite, ilealite, kanemite, layered titanic acid, smectite, synthetic smectite, finely powdered silicic acid, calcium silicate, aluminum silicate, calcium carbonate, magnesium carbonate, finely powdered talc, titanium oxide, diatomaceous earth, smectite, kaolin clay, etc. These swelling clays may be used alone or in combination.

[0081] The content of the swelling clay is preferably 0.1 to 10% by mass, 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 swelling clay is 0.1% by mass, the change in viscosity is small compared to when the clay is not added, so the effect of controlling the surface condition of the antiglare layer other than the convex portions may be insufficient. If the content of the swelling clay exceeds 10% by mass, the viscosity may be too high, resulting in insufficient coating suitability.

[0082] Even when the antiglare layer uses the swelling clay inorganic component, it can contain a mixture of organic fine particles, inorganic fine particles, and other inorganic components. By containing the above organic fine particles, inorganic fine particles and other inorganic components together with the above swelling clay inorganic component, the surface condition of the antiglare layer other than the relatively large convex portions formed on the surface of the antiglare layer can be suitably and diversifiedly controlled. As the organic fine particles, inorganic fine particles and other inorganic components, the same ones as those exemplified as the antiglare agent mentioned above can be used.

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

[0084] Examples of the ionizing radiation curable resin include compounds having one or more unsaturated bonds, such as compounds having functional groups such as 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, tripentaerythritol tetra ... Examples of the polyfunctional compounds include tetraocta(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, isobornyl 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. In addition, in the present invention, the above-mentioned compounds modified with PO, EO, etc. can also be used as the ionizing radiation curable resin.

[0085] In addition to the above compounds, relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiolpolyene resins, and the like having unsaturated double bonds can also be used as the ionizing radiation curable resin.

[0086] The ionizing radiation curable resin can be used in combination with a solvent drying type resin (a resin that can be made into a coating by simply drying a solvent added to adjust the solid content during coating, such as a thermoplastic resin.) By using a solvent drying type resin in combination, coating defects on the coating surface of the coating liquid can be effectively prevented when the antiglare layer is formed. The solvent drying type resin that can be used in combination with the ionizing radiation curable resin is not particularly limited, and generally, a thermoplastic resin can be used.

[0087] The thermoplastic resin is not particularly limited, and examples thereof include 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, phenol resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, melamine-urea co-condensation resins, silicon resins, silicone resins, and rubber or elastomers. The thermoplastic resin is preferably non-crystalline and soluble in an organic solvent (particularly a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, from the viewpoints of film-forming properties, transparency, and weather resistance, styrene resins, (meth)acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters, etc.), and the like are preferred.

[0088] The antiglare layer containing the above-mentioned antiglare agent and binder resin can be formed, for example, by applying a composition for an antiglare layer containing the antiglare agent, a monomer component of the binder resin, and a solvent onto a light-transmitting substrate, drying the composition to form a coating film, and curing the coating film by exposure to ionizing radiation or the like.

[0089] The particle size and content of the antiglare agent and the content of the binder resin are not particularly limited, and the shape of the surface of the antiglare layer described below may be appropriately adjusted so as to satisfy a surface condition that improves scratch resistance when a low refractive index layer is laminated thereon.

[0090] Examples of the solvent contained in the composition for an antiglare layer 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 may be used.

[0091] The composition for an antiglare layer preferably further contains a photopolymerization initiator. The photopolymerization initiator is not particularly limited, and may be the same as the photopolymerization initiator described in the composition for the low refractive index layer. The photopolymerization initiator may be used alone or in combination of two or more kinds. The composition for an antiglare layer is preferably used by mixing it with a photosensitizer, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

[0092] The content of the photopolymerization initiator in the composition for antiglare layer is preferably 0.5 to 10.0 parts by mass relative to 100 parts by mass of the binder resin. If it is less than 0.5 parts by mass, the hard coat performance of the antiglare layer formed may be insufficient, and if it exceeds 10.0 parts by mass, it may inhibit curing, which is not preferable.

[0093] The content (solid content) of the raw materials in the composition for an antiglare layer is not particularly limited, but is usually preferably 5 to 70% by mass, and particularly preferably 25 to 60% by mass.

[0094] The composition for an antiglare layer preferably contains a leveling agent. The leveling agent may be a fluorine-based leveling agent, a silicone-based leveling agent, a silicone / fluorine atom-containing leveling agent, etc., which may be used alone or in combination. Preferred are fluorine-based leveling agents and silicone / fluorine atom-containing leveling agents. The composition for an antiglare layer preferably contains a fluorine-based or silicone-based leveling agent as the leveling agent. The antiglare layer composition contains a leveling agent, which can suitably prevent the antiglare layer from forming a Benard cell structure. When a resin composition containing a solvent is applied and dried, a difference in surface tension occurs between the surface and inner surfaces of the coating film, which causes a large number of convection currents in the coating film. The structure caused by this convection is called a Benard cell structure, which causes problems such as orange peel and coating defects in the antiglare layer formed. In addition, the Benard cell structure has adverse effects such as excessively large unevenness on the surface of the antiglare layer, resulting in reduced transparency and whitish appearance, and the unevenness of the antiglare layer can cause distortion of transmitted light from inside the display device, resulting in scintillation that appears to sparkle in places on the image. By using the leveling agent described above, this convection can be prevented, so that not only can an uneven film without defects or unevenness be obtained, but the uneven shape can also be easily adjusted. In addition, the leveling agent contained in the composition for antiglare layer migrates to the composition for low refractive index layer when the composition for low refractive index layer is applied. If there is a problem with compatibility with the composition for low refractive index layer or with components such as the leveling agent and antifouling agent contained in the composition for low refractive index layer, the arrangement of hollow silica and the like contained in the low refractive index layer described below may be disturbed, and the uneven shape formed on the surface of the low refractive index layer may become large. In such a case, it is preferable that the composition for the antiglare layer contains a non-reactive leveling agent. The above-mentioned non-reactive leveling agent is unlikely to cause problems in terms of compatibility with the composition for the low refractive index layer described below, or with components such as the leveling agent and the antifouling agent contained in the composition for the low refractive index layer, and therefore can form a suitable uneven shape on the surface of the low refractive index layer.

[0095] As the non-reactive leveling agent, a lipophilic group-containing oligomer is preferably used. The content of the non-reactive leveling agent is preferably 0.025 to 0.50 parts by mass relative to 100 parts by mass of the binder resin in the antiglare layer. If the content of the non-reactive leveling agent is less than 0.025 parts by mass, the leveling power may be insufficient, resulting in uneven appearance. If the content of the non-reactive leveling agent is more than 0.50 parts by mass, the coating liquid may become more prone to foaming, which may cause defects. The more preferred lower limit of the content of the non-reactive leveling agent is 0.050 parts by mass, and the more preferred upper limit is 0.20 parts by mass.

[0096] The composition for an antiglare layer preferably contains only the non-reactive leveling agent as the leveling agent, but may contain other leveling agents as long as the effects of the present invention are not impaired.

[0097] The composition for an antiglare layer may contain a conventionally known dispersant, surfactant, antistatic agent, silane coupling agent, thickener, coloring inhibitor, colorant (pigment, dye), defoamer, flame retardant, ultraviolet absorber, adhesion promoter, polymerization inhibitor, antioxidant, surface modifier, lubricant, etc., depending on the purpose of increasing the hardness of the antiglare layer, suppressing cure shrinkage, controlling the refractive index, etc.

[0098] The composition for an antiglare layer may be used by mixing it with a photosensitizer, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

[0099] The method for preparing the composition for the antiglare layer is not particularly limited as long as it can uniformly mix the components, and can be carried out using known devices such as a paint shaker, a bead mill, a kneader, or a mixer.

[0100] The method for applying the composition for an antiglare layer onto a light-transmitting substrate is not particularly limited, and examples thereof include known methods such as spin coating, dipping, spraying, die coating, bar coating, roll coating, meniscus coating, flexographic printing, screen printing, and pad coating. After the composition for antiglare layer is applied by any of the above methods, the formed coating film is conveyed to a heated zone for drying, and the coating film is dried by various known methods to evaporate the solvent. Here, the distribution state of the aggregates of organic fine particles and silica fine particles can be adjusted by selecting the relative solvent evaporation rate, solid content concentration, coating solution temperature, drying temperature, drying air speed, drying time, solvent atmosphere concentration in the drying zone, etc. In particular, the method of adjusting the distribution state of the aggregates of the organic fine particles and the silica fine particles by selecting the drying conditions is simple and preferable.Specifically, the drying temperature is preferably 30 to 120°C, and the drying air speed is preferably 0.2 to 50 m / s.The distribution state of the aggregates of the organic fine particles and the silica fine particles can be adjusted to a desired state by performing a drying treatment appropriately adjusted within these ranges once or multiple times.

[0101] Examples of a method for irradiating the dried coating with ionizing radiation when curing the coating film include methods 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. The wavelength of the ultraviolet light may be in the range of 190 to 380 nm.Specific examples of the electron beam source include various electron beam accelerators such as Cockcroft-Wald type, Van de Graft type, resonant transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type.

[0102] The thickness of the antiglare layer is preferably 2.0 to 15.0 μm. If it is less than 2.0 μm, the surface of the antiglare layer may be easily scratched, and if it exceeds 15.0 μm, the antiglare layer may be easily cracked. The thickness of the antiglare layer is more preferably in the range of 2.0 to 7.0 μm, and even more preferably has an upper limit of 5.0 μm. The thickness of the antiglare layer can be measured by cross-sectional microscopic observation using a SEM, an optical microscope, or the like. By observation, it can be calculated as the arithmetic average value of measurements taken at any five points that are free of foreign matter, scratches, etc.

[0103] In the optical laminate of the present invention, one or more functional layers (antistatic layer, antifouling layer, adhesive layer, antireflective layer, other hard coat layer, etc.) may be appropriately formed on the surface of the light-transmitting substrate on which the antiglare 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 antiglare layer, as necessary, within a range that does not impair the effects of the present invention. Among them, it is preferable to have at least one layer of the antistatic layer and the antifouling layer. These layers may be the same as those of known antireflective laminates. As described above, the optical laminate of the present invention may have a functional layer such as an antifouling layer laminated on the low refractive index layer, but the functional layer is an extremely thin film that does not impair optical properties such as scratch resistance, antireflection, etc. The extremely thin film is, for example, a thin film having a thickness of 35 nm or less, and the thinner the better. In other words, the optical laminate of the present invention has the above-mentioned low refractive index layer as an essential component, and all physical properties obtained by the optical laminate of the present invention having such a low refractive index layer exhibit the same performance even when the above-mentioned extremely thin functional layer is laminated thereon. Therefore, the actual air interface of the optical laminate of the present invention may not be the low refractive index layer.

[0104] In addition, 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 is insufficient, and when the optical laminate of the present invention is attached to the surface of an image display device, the color reproducibility and visibility may be impaired. The total light transmittance is more preferably 90% or more, and even more preferably 91% or more. The total light transmittance can be measured according to JIS K7361 using an instrument such as "HM-150" manufactured by Murakami Color Research Laboratory. Furthermore, the optical laminate of the present invention is an anti-reflection film having a low refractive index layer on an anti-glare layer. The presence of an anti-glare layer alone can effectively prevent surrounding objects from being reflected, and the presence of a low refractive index layer on the anti-glare layer improves transparency, and has the effect of making images and characters appear clearer. In addition, a more preferable optical laminate can be obtained by controlling the luminous reflectance (%) calculated as the brightness perceived by the human eye, rather than simply the 5° regular reflectance (%). In the present invention, the preferred luminous reflectance (%) is 3.0% or less, and the lower the better, the more preferably it is 2.0% or less, and further preferably 1.0% or less. In order to maintain physical strength, it is difficult to achieve almost no reflection, such as about 0.1%, so the preferred range of 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 visual reflectance (%) can be determined, for example, by measuring the 5° specular reflectance in the wavelength range of 380 to 780 nm using a spectral reflectance meter (manufactured by Shimadzu Corporation, product name: UV-2450) and then calculating using software (built into the device) that converts it into the brightness perceived by the human eye.

[0105] In addition, the optical laminate of the present invention preferably has a haze of less than 15%. The antiglare layer may be composed of an internal haze caused by internal diffusion of the contained fine particles and an external haze caused by the uneven shape of the surface, and the internal haze caused by 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 of 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%. The internal haze is determined as follows. A resin having a refractive index equal to or less than 0.02 different from that of the resin forming the surface unevenness is applied to the unevenness on the surface of the low refractive index layer of the optical laminate with a wire bar so that the dry thickness is 8 μm (the thickness is the thickness that completely removes the unevenness on the surface and makes the surface flat). After drying at 70 °C for 1 minute, a 100 mJ / cm 2 The film is cured by irradiating it with ultraviolet light of 1000 nm. This causes the unevenness on the surface to collapse, resulting in a film with a flat surface. However, if the composition forming the uneven antiglare layer contains a leveling agent or the like, which makes the resin applied to the surface of the antiglare layer repel and difficult to wet, it is advisable to subject the surface of the antiglare layer to a hydrophilic treatment in advance by saponification treatment (immersing the surface of the antiglare layer in a 2 mol / L NaOH (or KOH) solution at 55°C for 3 minutes, washing with water, completely removing water droplets with Kimwipe (registered trademark) or the like, and then drying in an oven at 50°C for 1 minute). This film with a flat surface has no surface irregularities, and therefore only has internal haze. The internal haze can be calculated by measuring the haze of this film in the same way as the haze in accordance with JIS K-7136. The external haze can be calculated as (haze-internal haze). For simplicity, an optically transparent adhesive film having an adhesive layer with a lower refractive index than the resin that forms the surface irregularities can be used instead of the resin layer for calculation. In that case, the haze of the optically transparent adhesive film is measured in advance and subtracted from the internal haze.

[0106] The optical laminate of the present invention preferably has a contrast ratio of 80% or more, more preferably 90% or more. If it is less than 80%, when the optical laminate of the present invention is attached to the surface of a display, the darkroom contrast may be poor and visibility may be impaired. In this specification, the above contrast ratio is a value measured by the following method. That is, the L of the luminance of light passing through a backlight unit in which a diffusion plate is attached to a cold cathode tube light source is used, and two polarizing plates (AMN-3244TP manufactured by Samsung) are used and the polarizing plates are arranged in parallel Nicol is measured. max The brightness of the light passing through the crossed Nicols is L min Divided by (L max / L min ) is the contrast, and the contrast ratio is calculated by dividing the contrast (L1) of the optical laminate (light-transmitting substrate + antiglare layer, etc.) by the contrast (L2) of the light-transmitting substrate (L1 / L2) x 100 (%). The luminance is measured in a darkroom. A color luminance meter (Topcon BM-5A) is used to measure the luminance. The measurement angle of the color luminance meter is set to 1°, and the measurement is performed with a field of view of φ5 mm on the sample. The light quantity of the backlight is measured as luminance of 3600 cd / m2 when two polarizing plates are placed in parallel Nicol without a sample being placed. 2 Set it so that

[0107] Furthermore, for the optical laminate of the present invention, the 60° gloss value has a preferred lower limit of 100, a more preferred lower limit of 105, and an even more preferred lower limit of 110, and a preferred upper limit of 160, and a more preferred upper limit of 150. The 60° gloss was measured in gloss (%) in accordance with JIS Z 8741 using a precision gloss meter GM-26PRO (Murakami Color Research Laboratory Co., Ltd.). The size of the sample was 5 cm x 10 cm, and the back surface of the sample (the surface without the antiglare layer) was measured by contacting it with a blackboard using an air suction method. FIG. 3 is a diagram for explaining a method of measuring gloss (angle) in accordance with JIS Z 8741. As shown in Figure 3, 60° is an image of anti-glare properties when viewed from an oblique angle. In other words, 60° gloss makes it possible to control the anti-glare properties to a desirable level regardless of the viewing angle, even in the case of a large screen. Furthermore, in the optical layered body of the present invention, the lower limit of the 20° gloss is preferably 70, more preferably 75, and even more preferably 80; As shown in FIG. 3, 20° is an image of anti-glare properties when viewed from the front (i.e., 20° from the angle perpendicular to the screen), and is an angle that is particularly important whether the TV or monitor is large or small, and it is important that the anti-glare properties are preferable here. Therefore, by controlling this gloss, it is possible to control the anti-glare properties that are preferable to have as standard. This screen front direction is an angle range in which the person viewing the screen is likely to be reflected, so a surface shape in which the 20° gloss value in the front direction is smaller than the 60° gloss value viewed from the above oblique direction is preferable. A lower gloss value means that the anti-glare properties are high and the image is less likely to be reflected. However, in order to obtain an optical laminate with excellent anti-reflection performance and high transparency, the anti-glare ratio (%) of the 20° gloss in the front direction to the 60° gloss in the oblique direction is preferably 65% ​​to 95%. If it is less than 65%, the front anti-glare property tends to be too strong and transparency decreases, and if it is more than 95%, in other words, if the 20° and 60° gloss are roughly the same, the front anti-glare property tends to be too low and the viewer may be bothered by their own reflection. By simultaneously satisfying the above-mentioned preferred ranges of 20° gloss and 60° gloss, the optical layered body of the present invention has excellent antiglare performance. Furthermore, by simultaneously setting the reflectance (visible reflectance), total light transmittance, 20° gloss, and 60° gloss within the preferred ranges, the visibility of displays such as large screens of 50 inches or more and monitors for watching videos is particularly good regardless of the viewing angle, which is preferable as the antiglare property of the antiglare layer / low refractive index layer of the optical laminate of the present invention. The optical laminate of the present invention has optical properties that make it easy to view from any angle, as well as excellent scratch resistance, and therefore can be said to be very suitable for large-screen digital signage, which has been widely used in recent years. In the present invention, the gross unit (%) is omitted.

[0108] In the case where other components such as a cover glass, a film, a polarizing element, or a display element are further laminated via a pressure-sensitive adhesive layer or the like on the light-transmitting substrate surface opposite the side on which the low refractive index layer is laminated in the optical laminate of the present invention, the optical properties such as gloss, reflectance (visual reflectance), total light transmittance, haze, contrast ratio, etc. of the optical laminate may be measured after peeling off and removing the pressure-sensitive adhesive layer and the components, or after performing a pretreatment to make the film thickness of the pressure-sensitive adhesive layer, etc. 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 the fine particles in the antiglare layer, can be measured directly without carrying out 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 sheet cut to a predetermined size, or in the form of a roll obtained by winding a long sheet into a roll. The size of the above-mentioned sheet is not particularly limited, but the maximum diameter is about 2 to 500 inches. The "maximum diameter" refers to the maximum length when any two points on the optical laminate are connected. For example, when the optical laminate is rectangular, the diagonal line of the region is the maximum diameter. When the optical laminate is circular, the diameter is the maximum diameter. In addition, when the optical laminate of the present invention is in the form of a roll, the width and length of the long sheet wound into a roll are not particularly limited, but generally, the width is about 300 to 3000 mm, and the length is about 50 to 5000 m. The optical laminate of the present invention in the form of a roll can be cut into sheets according to the size of a display device or the like. When cutting, it is preferable to exclude the ends of the roll, which have unstable physical properties. The shape of the sheet is not particularly limited, and may be, for example, a polygon (triangle, square, pentagon, etc.), a circle, or a random, indefinite shape. More specifically, when the optical laminate of the present invention is a square shape, the aspect ratio is not particularly limited as long as it does not cause any problems as a display screen. For example, the aspect ratio may be 1:1, 3:4, 10:16, 9:16, 1:2, etc., but in vehicle-mounted applications and digital signage that are rich in design, the aspect ratio is not limited to these.

[0110] The optical laminate of the present invention may further include other optical members such as a polarizing element and a retardation film. For example, the optical laminate of the present invention may include an optical laminate having the above-mentioned antiglare layer or the like on at least one surface of a light-transmitting substrate, and further having 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, its layer structure may be a structure in which a light-transmitting base material and an anti-glare layer, etc. are laminated in order on at least one surface of the polarizing element. Specifically, a structure in which a light-transmitting base material and an anti-glare layer, etc. are laminated in order on one surface of the polarizing element, and a polarizing element protective film is laminated on the other surface, or a structure in which a polarizing element protective film is laminated on both sides of the polarizing element, and a light-transmitting base material and an anti-glare layer, etc. are laminated in order on one polarizing element protective film, etc., may be mentioned. In these optical laminates, the surface on the anti-glare layer side is usually the light output surface. The optical laminate having the above polarizing element can also be used as a polarizing plate. Such a polarizing plate also constitutes one aspect of the present invention. That is, the present invention also relates to a polarizing plate comprising a polarizing element, characterized in that the polarizing element is provided with the optical laminate of the present invention on a surface thereof.

[0111] The polarizing element is not particularly limited, and for example, a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymer-based saponified film, etc., which are dyed with iodine or the like and stretched, can be used. In laminating the polarizing element and the optical laminate of the present invention, it is preferable to saponify the light-transmitting substrate (triacetyl cellulose film). The saponification improves adhesion and can also provide 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 also relates to a display panel comprising the optical laminate of the present invention or the polarizing plate of the present invention. The present invention also relates to an image display device comprising the optical laminate of the present invention or the polarizing plate of the present invention. The display panel is a viewer-side component of a display. Taking a liquid crystal display as an example, the display panel is a component including two glass plates (e.g., a color filter substrate and an array substrate) enclosing a liquid crystal material, a polarizing element (a polarizing element and a polarizing element protective film, etc.), 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 disposed so that the upper surface of the antiglare layer of the optical laminate faces the observer side (the light output surface of the image display device).Furthermore, it is preferable to place the optical laminate of the present invention on the surface of the image display device, and to use the optical laminate of the present invention so that the upper surface of the antiglare layer of the optical laminate faces the observer side (the light output surface of the display device).

[0114] The optical laminate of the present invention and the polarizing element may be cut into sheets according to the size of the display device and then bonded together, or roll-shaped members may be bonded together. When roll-shaped members are bonded together, they may be subsequently cut to fit the size of the display device. When the optical laminate of the present invention is applied to a display device such as a liquid crystal display device, the optical laminate in a sheet or roll form may be laminated with a display element or the like described below, and then cut to fit the size of the display device. When cutting, it is preferable to exclude the ends of the roll, which have unstable physical properties.

[0115] [Image display device] The image display device in which the optical laminate of the present invention is installed is characterized by being equipped with the optical laminate of the present invention or the polarizing plate of the present invention described above. 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 optical laminate of the present invention or the polarizing plate of the present invention described above on the observer side (the light output surface side of the image display device) of a display element such as a liquid crystal display element, a plasma display element, or an organic EL display element. More specifically, it is preferable that the image display device is equipped with the optical laminate or the polarizing plate of the present invention described above on the observer side surface of the display element, and is arranged so that the upper surface (surface having an uneven shape) of the antiglare layer or the like of the optical laminate or the polarizing plate faces the observer side. The size of the image display device is not particularly limited, but the maximum diameter is about 2 to 500 inches. The "maximum diameter" refers to the maximum length when any two points on the display device are connected. For example, if the display device is rectangular, the diagonal line of the area is the maximum diameter, and if it is circular, the diameter is the maximum diameter.

[0116] The image display device may be an image display device such as an LCD, a PDP, an FED, an ELD (organic EL, inorganic EL), a micro LED display, a CRT, a tablet PC, a touch panel, or electronic paper.

[0117] The LCD, which is a typical example of the above, comprises a transparent display and a light source device that irradiates the transparent display from the back side. 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 where the present invention is a liquid crystal display device having the optical laminate, the light source of the light source device is irradiated from the lower side of the optical laminate. A retardation plate may be inserted between the liquid crystal display element and the polarizing plate. An adhesive layer may be provided between each layer of the liquid crystal display device as necessary.

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

[0120] The image display device may be an ELD device in which a light emitter such as zinc sulfide or a diamine substance that emits light when a voltage is applied is deposited on a glass substrate and the voltage applied to the substrate is controlled to display an image, or an image display device such as a CRT that converts an electric signal 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 the front panel thereof.

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

[0122] Since the optical layered body of the present invention has the above-mentioned configuration, it can be an optical layered body having excellent scratch resistance. In addition, it has suitable antiglare properties and excellent transparency. Therefore, the optical laminate of the present invention can be suitably applied to the display surfaces for high-definition images such as cathode ray tube displays (CRTs), liquid crystal displays (LCDs), plasma displays (PDPs), electroluminescence displays (organic or inorganic ELDs), micro LED displays, field emission displays (FEDs), touch panels, electronic paper, etc. It can also be suitably used for the image display surfaces of foldable, bendable, or rollable image display devices and touch panels. [Brief description of the drawings]

[0123] [Figure 1] FIG. 1 is a diagram illustrating the nanoindentation method, where (a) is a schematic diagram showing how an indenter is pressed into or unloaded from a sample, and (b) is a graph showing an example of an indentation load-indentation depth curve. [Diagram 2] FIG. 2 is a schematic diagram illustrating an example of a Berkovich indenter. [Diagram 3] FIG. 1 is a diagram for explaining a method for measuring gloss (angle) in accordance with JIS Z 8741. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0124] The present invention will be described with reference to the following examples, 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. In all measurements and evaluations, a wrinkle-free and unstained part of the sample was used, and the measurement sample was taken not from the edge of the manufactured sample, but from the vicinity of the center, which is considered to be a relatively stable coating film.

[0126] <Optical laminate of the first aspect of the present invention> Example 1 A light-transmitting 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 composition shown below was applied to one side of the light-transmitting substrate to form a coating film. Next, dry air at 70°C was passed through the formed coating film at a flow rate of 0.2 m / s for 15 seconds, and then dry air at 70°C was passed through the coating film at a flow rate of 10 m / s for an additional 30 seconds to evaporate the solvent in the coating film, and ultraviolet rays were irradiated at an integrated light intensity of 30 mJ / cm. 2 The coating was cured by irradiating the coating with light so as to form an antiglare layer having a thickness of 5 μm (when cured). (Composition for anti-glare layer) Tetrafunctional acrylate monomer (product name: SR295, manufactured by Sartomer Corporation) 50 parts by weight Urethane acrylate oligomer (product name: UV1700B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 50 parts by weight Irgacure 184 (BASF Japan) 3 parts by weight 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 Plastics Co., Ltd.) 3 parts by weight Fumed silica (octylsilane treatment; 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 weight

[0127] Next, a composition for a low refractive index layer having the following composition was applied to the surface of the formed antiglare layer so that the film thickness after drying (40°C x 1 minute) would be 0.11 μm, and the composition was irradiated with an ultraviolet ray irradiation device (manufactured by Fusion UV Systems Japan, light source H bulb) in a nitrogen atmosphere (oxygen concentration 200 ppm or less) with an integrated light amount of 100 mJ / cm. 2 The resin was cured by irradiating it with ultraviolet light at a temperature of 100° C. to form a low refractive index layer, thereby producing the optical laminate according to Example 1. (Composition for low refractive index layer) Trifunctional acrylate monomer (product name: SR444, manufactured by Sartomer Corporation) 100 parts by weight Hollow silica fine particles (average particle size: 50 nm, manufactured by JGC Catalysts and Chemicals) 180 parts by weight Solid silica fine particles (average particle size: 12 nm, manufactured by Nissan Chemical Industries, Ltd.) 60 parts by mass Irgacure 184 (BASF Japan) 10 parts by weight Reactive fluorine-based leveling agent (RS-78, manufactured by DIC Corporation) 8 parts by weight Methyl isobutyl ketone 10,000 parts by mass

[0128] Example 2 A composition for a low refractive index layer was prepared in the same manner as in Example 1, except that the amount of solid silica fine particles in the composition for a low refractive index layer was 20 parts by mass, and an optical laminate for Example 2 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer was used.

[0129] Example 3 A composition for a low refractive index layer was prepared in the same manner as in Example 1, except that the amount of solid silica fine particles in the composition for a low refractive index layer was 100 parts by mass, and an optical laminate for Example 3 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer was used.

[0130] Example 4 A composition for a low refractive index layer was prepared in the same manner as in Example 1, except that solid silica fine particles were not added to the composition for a low refractive index layer. An optical laminate of Example 4 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer was used.

[0131] Example 5 A composition for antiglare layer 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 the non-reactive fluorine-based leveling agent (product name: F554, manufactured by DIC Corporation) in the composition for antiglare layer. An optical laminate of Example 5 was produced in the same manner as in Example 4, except that the composition for antiglare layer was used.

[0132] Example 6 A composition for a low refractive index layer was prepared in the same manner as in Example 1, except that the amount of solid silica fine particles in the composition for a low refractive index layer was 110 parts by mass, and an optical laminate of Example 6 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer was used.

[0133] Example 7 A composition for a low refractive index layer was prepared in the same manner as in Example 1, except that the amount of solid silica fine particles in the composition for a low refractive index layer was 80 parts by mass, and an optical laminate of Example 7 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer was used.

[0134] Example 8 A composition for a low refractive index layer was prepared in the same manner as in Example 7, except that in the composition for a low refractive index layer, a bifunctional acrylate monomer (product name: M240, manufactured by Toa Gosei Co., Ltd.) was used instead of the trifunctional acrylate monomer, and an optical laminate for Example 8 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer was used.

[0135] Example 9 A composition for a low refractive index layer was prepared in the same manner as in Example 7, except that in the composition for a low refractive index layer, the trifunctional acrylate monomer was replaced with a hexafunctional acrylate monomer (product name: DPHA, manufactured by Sartomer Corporation). An optical laminate for Example 9 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer 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 silicone fluorine atom-containing additive (KY-1203, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of the reactive fluorine-based leveling agent (RS-78, manufactured by DIC Corporation) in the composition for a low refractive index layer. An optical laminate of Example 10 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer was used.

[0137] Example 11 A composition for a low refractive index layer 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 the reactive fluorine-based leveling agent (RS-78, manufactured by DIC Corporation) in the composition for a low refractive index layer. An optical laminate for Example 11 was produced in the same manner as in Example 1, except that the composition for a low refractive index layer was used.

[0138] Comparative Example 1 A composition for an antiglare layer 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, Inc.) was used instead of the non-reactive fluorine-based leveling agent (product name: F554, manufactured by DIC Corporation) in the composition for an antiglare layer. An optical laminate of Comparative Example 1 was produced in the same manner as in Example 4, except that the composition for an antiglare layer was used.

[0139] Comparative Example 2 A composition for a low refractive index layer 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 Corporation) was used instead of the trifunctional acrylate monomer (product name: SR444, manufactured by Sartomer Corporation) in the composition for a low refractive index layer. An optical laminate for Comparative Example 2 was produced in the same manner as in Comparative Example 1, except that the composition for a low refractive index layer was used.

[0140] (Measurement of the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the surface of the low refractive index layer) AFM: SPM-9600 (manufactured by Shimadzu Corporation) was used, and measurements were performed under the following conditions, and calculations were performed. The definition of the surface roughness parameters obtained by AFM is specified in JIS B0031 (1994), but in the case of AFM, it can be calculated as the surface average value within the scanning range (field of view area) using the software attached to the SPM-9600. However, the AFM measurements were performed excluding areas where defects such as specific detachment or irregularities were observed. Cantilever: NCH-W (Nano World) Scanning range: 5μm (field of view area 5μm×5μm) Scanning speed: 1Hz Analysis software: SPM Manager Version 4.36.10 <Preparation of measurement sample> 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 end of the sample with tweezers and cut it with scissors to create a sample that is 8 mm x 8 mm in size, smaller than the carbon tape. (3) Blow the front and back of the sample with a blower to remove any foreign matter. (4) The sample was placed with the front (measurement surface) facing up and carbon tape was attached to the back of the sample to prepare a measurement sample. <Arithmetic mean roughness Ra> The arithmetic mean roughness Ra was calculated in accordance with JIS B0031 (1994) by cutting out only a reference length (l) in the direction of the mean line from the roughness curve of the surface of the obtained measurement sample, plotting the X-axis in the direction of the mean line of this cut-out portion and the Y-axis in the direction of the longitudinal magnification, and expressing the roughness curve 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: Nanoindentation hardness (MPa) measurement) Measurements were performed using a HYSITRON "TI950 TriboIndenter" under the following conditions in displacement control mode: A Berkovich indenter (triangular pyramid, made of diamond, with a 115 degree indentation angle) was pressed 30 nm into the low refractive index layer at a loading rate of 10 nm / s, held for a certain period of time to relax the residual stress, and then unloaded to obtain a load-displacement curve. The indentation hardness was then automatically calculated by the device. Calculation overview: Using the unloading curve, the contact depth of the sample with the indenter is calculated, and the contact projected area (A (nm 2 ) is obtained, and the indentation hardness is automatically calculated by the device using this area and the maximum load after relaxation (Pmax (μN)) as 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 the measurement was performed on a part that was as flat as possible without any particular defects, avoiding parts with extremely uneven structures.

[0142] <Preparation of measurement sample> The optical laminate cut into a size of 20 mm x 20 mm was fixed to a commercially available slide glass with the low refractive index layer side facing up via an adhesive resin (product name "Aron Alpha (registered trademark) general use", manufactured by Toa Gosei Co., Ltd.). Specifically, the adhesive resin was dripped onto the center of slide glass 1 (product name "Slide glass (cut type) 1-9645-11", manufactured by AS ONE Co., Ltd.). At this time, the adhesive resin was not spread, and only one drop was dripped so that the adhesive resin would not protrude from the optical laminate when it was pressed down as described below. Thereafter, the optical laminate cut to the above size was brought into contact with the glass slide so that the low refractive index layer side was on top and the adhesive resin was positioned in the center of the optical laminate, and the adhesive resin was spread between the glass slide 1 and the optical laminate to temporarily bond them. Then, another new slide glass 2 was placed on the optical laminate to obtain a laminate of slide glass 1 / adhesive resin / optical laminate / slide glass 2. Next, a weight of 30 g to 50 g was placed on the glass slide 2, and the glass slide 2 was left in this state for 12 hours at room temperature. After that, the weight and the glass slide 2 were removed, and this was used as a measurement sample. The obtained measurement sample was then fixed to the measurement stage of a HYSITRON "TI950 TriboIndenter" placed parallel to a vibration isolation table. The indentation hardness is measured at any five points near the center of the surface of the low refractive index layer of the measurement sample (area where the adhesive resin is present), and the arithmetic average of the hardness values ​​obtained at the five points is determined. However, the five arbitrary measurement points were selected by observing the low refractive index layer using a microscope at a magnification of 50x to 500x, and selecting points from areas that were as flat as possible, avoiding areas with extremely convex structures and areas with extremely concave structures.

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

[0144] (Scratch resistance test) A scratch resistance test was carried out using a steel wool tester (model SJTR-053, manufactured by SAM JEE TECH) under the following conditions. [Preparing steel wool] Cut the steel wool to a square (7cm x 7cm). Fix the steel wool using a cable tie so that it fits into the lower of the two recesses on the steel wool test head. Install the steel wool without any wrinkles or slack. Set the steel wool so that the test direction is perpendicular to the direction of the steel wool fibers. [Check the level] Loosen the stopper to allow the head to move up and down freely. With no weight attached, set the "CYLINDER" to DOWN and lower the head to check that it is level. [Smoothing steel wool] Since the steel wool has a fuzzy surface, we smoothed it out by "smoothing" it. <Breaking-in conditions> Weight 500g, test speed (100mm / s), 200 strokes. [Installation of test specimen] Sample size: short side 3cm, long side 25cm If there is any dirt on the cut test piece or base, gently wipe it off with a cloth. The test piece is placed on the base with the coated side facing up, without any slack. [test] Specified load: 700g / cm 2 , test speed (100mm / s) Test temperature: 25℃, Test humidity: 50% [evaluation] After the test, apply black vinyl tape (Yamato vinyl tape No. 200-38-21 38mm width) and check for scratches or discoloration under three-wavelength fluorescent lamps (1300-1700 lux). The angle between the light source and the test piece, and between the test piece and the inspector should be approximately 45 degrees, and judged at the angle where scratches and discoloration are particularly visible. The folded parts (3 cm from both ends) are not considered because they are prone to scratches. Thereafter, the surface of the low refractive index layer was visually inspected for the presence or absence of scratches and was evaluated according to the following criteria. ◎: No scratches or discoloration ○: Discoloration is faintly visible △: Scratches and discoloration are faintly visible ×: Scratches and discoloration are visible

[0145] (5° specular reflectance measurement) A black vinyl tape (Yamato vinyl tape No. 200-38-21, 38 mm width) was applied to the measurement side of each optical laminate, opposite the side on which the low refractive index layer was provided, and then the 5° specular reflectance (%) on the surface of the optical laminate was measured in the wavelength range of 380 to 780 nm using an ultraviolet-visible spectrophotometer (UV-2450, manufactured by Shimadzu Corporation). (Reflectance: Luminous reflectance measurement) Using the 5° regular reflectance (%) data measured above, the value indicating the visual reflectance was calculated as the reflectance (%) using software (built into the device) that converts it into the brightness perceived by the human eye. The average value of the reflectance at five points for each sample was recorded as the reflectance (%) of each sample: visual reflectance measurement result (Table 1).

[0146] [Table 1]

[0147] In the optical laminates according to the examples in which the unevenness Ra in any 5 μm square area on the surface of the low refractive index layer was 4 nm or less and Rz was 60 nm or less, both the scratch resistance and antireflection performance were excellent. In particular, Examples 4 and 5, in which Ra in a microscopic field was 2.0 nm or less, Rz was 25 nm or less, and the indentation hardness was 440 MPa or more, and Example 7, in which Ra in a microscopic field was 3.0 nm or less, Rz was 45 nm or less, and the indentation hardness was 500 MPa or more, had excellent scratch resistance. In particular, Examples 1 and 2, in which the Ra in a microscopic field was 2.0 nm or less, the Rz was 35 nm or less, and the indentation hardness was 500 MPa or more, and Example 9, in which the Ra in a microscopic field was 3.0 nm or less, the Rz was 45 nm or less, and the indentation hardness was 600 MPa or more, had extremely excellent scratch resistance. On the other hand, in the optical laminate of the comparative example in which the Ra and Rz of the unevenness in any 5 μm square area on the surface of the low refractive index layer are outside the specific range, neither excellent scratch resistance nor anti-reflection performance was obtained. The optical laminate according to the first embodiment of the present invention had a total light transmittance of 90% or more as measured using Murakami Color Research Laboratory's "HM-150" in accordance with JIS K7361, and had a 20° gloss value in the range of 80 to 140 and a 60° gloss value in the range of 110 to 160 as measured using a precision gloss meter GM-26PRO (Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS Z 8741. The 20° gloss value / 60° gloss value×100(%) was 70 to 90(%). The size of the sample used for gloss measurement was 5 cm x 10 cm, and the measurement was made by pressing the back side of the sample against a blackboard using the air suction method and measuring three times, and the average value was recorded as the measured value.

[0148] <Optical laminate of the second aspect of the present invention>

[0149] Example 12 A light-transmitting 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 composition shown below was applied to one side of the light-transmitting substrate to form a coating film. Next, dry air at 70°C was passed through the formed coating film at a flow rate of 0.2 m / s for 15 seconds, and then dry air at 70°C was passed through the coating film at a flow rate of 10 m / s for an additional 30 seconds to evaporate the solvent in the coating film, and ultraviolet rays were irradiated at an integrated light intensity of 30 mJ / cm. 2 The coating was cured by irradiating the coating with light so as to form an antiglare layer having a thickness of 5 μm (when cured). (Composition for anti-glare layer) Tetrafunctional acrylate monomer (product name: SR295, manufactured by Sartomer Corporation) 50 parts by weight Urethane acrylate oligomer (product name: UV1700B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 50 parts by weight Irgacure 184 (BASF Japan) 3 parts by weight 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 Plastics Co., Ltd.) 3 parts by weight Fumed silica (octylsilane treatment; 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 weight

[0150] Next, a composition for a low refractive index layer having the following composition was applied to the surface of the formed antiglare layer so that the film thickness after drying (40°C x 1 minute) would be 0.11 μm, and the composition was irradiated with an ultraviolet ray irradiation device (manufactured by Fusion UV Systems Japan, light source H bulb) in a nitrogen atmosphere (oxygen concentration 200 ppm or less) with an integrated light amount of 100 mJ / cm. 2 The resin was cured by irradiating it with ultraviolet light at a temperature of 100° C. to form a low refractive index layer, thereby producing an optical laminate according to Example 10. (Composition for low refractive index layer) Trifunctional acrylate monomer (product name: SR444, manufactured by Sartomer Corporation) 100 parts by weight Hollow silica fine particles (average primary particle diameter: 50 nm, product name: Sururia DAS, manufactured by JGC Catalysts and Chemicals) 180 parts by mass Solid silica fine particles (average primary particle diameter: 12 nm, product name: MIBK-AC-2140Z, manufactured by Nissan Chemical Industries, Ltd.) 10 parts by mass Irgacure 184 (BASF Japan) 10 parts by weight Reactive silicone leveling agent (RS-57, manufactured by DIC Corporation) 3 parts by weight Methyl isobutyl ketone 10,000 parts by mass

[0151] (Example 13) A composition for a low refractive index layer was prepared in the same manner as in Example 10, except that no solid silica fine particles were added to the composition for a low refractive index layer. An optical laminate of Example 13 was produced in the same manner as in Example 12, except that the composition for a low refractive index layer 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 in the composition for a low refractive index layer, a reactive silicone-based leveling agent (RS-57, manufactured by DIC Corporation) was replaced with a reactive fluorine-based leveling agent (RS-71, manufactured by DIC Corporation). An optical laminate for Example 14 was produced in the same manner as in Example 12, except that the composition for a low refractive index layer was used.

[0153] Example 15 A composition for antiglare layer was prepared in the same manner as in Example 12, except that the amount of the urethane acrylate oligomer in the composition for antiglare layer was 100 parts by mass, and an optical laminate for Example 13 was produced in the same manner as in Example 15, except that the composition for antiglare layer was used.

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

[0155] Comparative Example 3 A composition for a low refractive index layer was prepared in the same manner as in Example 12, except that methyl isobutyl ketone / methyl ethyl ketone (5000 parts by mass / 5000 parts by mass) was used as a solvent instead of 10,000 parts by mass of methyl isobutyl ketone in the composition for a low refractive index layer. An optical laminate for Comparative Example 3 was produced in the same manner as in Example 12, except that the composition for a low refractive index layer was used.

[0156] Comparative Example 4 A composition for a low refractive index layer was prepared in the same manner as in Example 12, except that the amount of solid silica fine particles in the composition for a low refractive index layer was 60 parts by mass, and an optical laminate for Comparative Example 4 was produced in the same manner as in Example 12, except that the composition for a low refractive index layer was used.

[0157] (Measurement of the arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the surface of the low refractive index layer) AFM: SPM-9600 (manufactured by Shimadzu Corporation) was used, and measurements were performed under the following conditions, and calculations were performed. The definition of the surface roughness parameters obtained by AFM is specified in JIS B0031 (1994), but in the case of AFM, it can be calculated as the surface average value within the scanning range (field of view area) using the software attached to the SPM-9600. However, the AFM measurements were performed excluding areas where defects such as specific detachment or irregularities were observed. Cantilever: NCH-W (Nano World) Scanning range: 5μm (field of view area 5μm×5μm) Scanning speed: 1Hz Analysis software: SPM Manager Version 4.36.10 <Preparation of measurement sample> 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 end of the sample with tweezers and cut it with scissors to create a sample that is 8 mm x 8 mm in size, smaller than the carbon tape. (3) Blow the front and back of the sample with a blower to remove any foreign matter. (4) The sample was placed with the front (measurement surface) facing up and carbon tape was attached to the back of the sample to prepare a measurement sample. <Arithmetic mean roughness Ra> The arithmetic mean roughness Ra was calculated in accordance with JIS B0031 (1994) by cutting out only a reference length (l) in the direction of the mean line from the roughness curve of the surface of the obtained measurement sample, plotting the X-axis in the direction of the mean line of this cut-out portion and the Y-axis in the direction of the longitudinal magnification, and expressing the roughness curve as y = f(x). The value obtained by the following formula was expressed in micrometers (μm) to obtain Ra.

number

number

[0158] (Hardness of the low refractive index layer surface: Measurement of indentation hardness (MPa)) Measurements were performed using a HYSITRON "TI950 TriboIndenter" under the following conditions in displacement control mode: A Berkovich indenter (triangular pyramid, made of diamond, ridge angle 115 degrees) was pressed into the low refractive index layer by 30 nm or 300 nm at a loading rate of 10 nm / s, and the indenter was held for a certain period of time to relax the residual stress, after which 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 of the sample with the indenter is calculated, and the contact projected area (A (nm 2 ) is obtained, and the indentation hardness is automatically calculated by the device using this area and the maximum load after relaxation (Pmax (μN)) as 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 the measurement was performed on a part that was as flat as possible without any particular defects, avoiding parts with extremely uneven structures.

[0159] <Preparation of measurement sample> The optical laminate cut into a size of 20 mm x 20 mm was fixed to a commercially available slide glass with the low refractive index layer side facing up via an adhesive resin (product name "Aron Alpha (registered trademark) general use", manufactured by Toa Gosei Co., Ltd.). Specifically, the adhesive resin was dripped onto the center of slide glass 1 (product name "Slide glass (cut type) 1-9645-11", manufactured by AS ONE Co., Ltd.). At this time, the adhesive resin was not spread, and only one drop was dripped so that the adhesive resin would not protrude from the optical laminate when it was pressed down as described below. Thereafter, the optical laminate cut to the above size was brought into contact with the glass slide so that the low refractive index layer side was on top and the adhesive resin was positioned in the center of the optical laminate, and the adhesive resin was spread between the glass slide 1 and the optical laminate to temporarily bond them. Then, another new slide glass 2 was placed on the optical laminate to obtain a laminate of slide glass 1 / adhesive resin / optical laminate / slide glass 2. Next, a weight of 30 g to 50 g was placed on the glass slide 2, and the glass slide 2 was left in this state for 12 hours at room temperature. After that, the weight and the glass slide 2 were removed, and this was used as a measurement sample. The obtained measurement sample was then fixed to the measurement stage of a HYSITRON "TI950 TriboIndenter" placed parallel to a vibration isolation table. The indentation hardness is measured at any five points near the center of the surface of the low refractive index layer of the measurement sample (area where the adhesive resin is present), and the arithmetic average of the hardness values ​​obtained at the five points is determined. However, the five arbitrary measurement points were selected by observing the low refractive index layer using a microscope at a magnification of 50x to 500x, and selecting points from areas that were as flat as possible, avoiding areas with extremely convex structures and areas with extremely concave structures.

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

[0161] (Measurement of water contact angle) The contact angle of pure water was measured using a solid-liquid interface analyzer "Drop Master 300" manufactured by Kyowa Interface Science Co., Ltd. 1.0 μL of pure water was dropped onto the surface of the low refractive index layer of the optical laminate, and 1 second after the drop landed, the contact angle was calculated from the angle of the line connecting the left and right end points of the dropped drop to the apex relative to the solid surface according to the θ / 2 method. The average value of 5 measurements was taken as the contact angle value.

[0162] (Scratch resistance test) The surface of the low refractive index layer of the optical laminate was coated with BONSTAR #0000 steel wool (product name: BON STAR, manufactured by BONSTAR Sales Co., Ltd.) at a density of 700 g / cm 2 The surface of the low refractive index layer was then visually inspected for the presence or absence of scratches and evaluated according to the following criteria. ◎: No scratches or discoloration ○: Discoloration is faintly visible ×: Scratches and discoloration are visible

[0163] (5° specular reflectance measurement) A black vinyl tape (Yamato vinyl tape No. 200-38-21, 38 mm width) was applied to the measurement side of each optical laminate, opposite the side on which the low refractive index layer was provided, and then the 5° specular reflectance (%) on the surface of the optical laminate was measured in the wavelength range of 380 to 780 nm using an ultraviolet-visible spectrophotometer (UV-2450, manufactured by Shimadzu Corporation). (Reflectance: Luminous reflectance measurement) Using the 5° regular reflectance (%) data measured above, the value indicating the visual reflectance was calculated as the reflectance (%) using software (built into the device) that converts it into the brightness perceived by the human eye. The average value of the reflectance at five points for each sample was recorded as the reflectance (%) of each sample: visual reflectance measurement result (Table 2).

[0164] [Table 2]

[0165] In the optical laminates according to the examples in which the Ra of the unevenness in any 5 μm square region on the surface of the low refractive index layer is 1.5 nm or less and the Rz is 30 nm or less, and the hardness measured by the nanoindentation method when the indenter is pressed 300 nm is higher than the hardness measured by the nanoindentation method when the indenter is pressed 30 nm, both the scratch resistance and the anti-reflection performance were excellent. In particular, in Examples 1 and 2, in which the Ra in a 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 had a penetration depth of 30 nm and the indentation hardness when the indenter had a penetration depth of 300 nm was 30 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 area on the surface of the low refractive index layer were outside the specific range, excellent scratch resistance was not obtained. The optical laminate according to the second embodiment of the present invention had a total light transmittance of 90% or more as measured using Murakami Color Research Laboratory's "HM-150" in accordance with JIS K7361, and had a 20° gloss value in the range of 70 to 140 and a 60° gloss value in the range of 100 to 160 as measured using a precision gloss meter GM-26PRO (Murakami Color Research Laboratory) in accordance with JIS Z 8741. The 20° gloss value / 60° gloss value×100(%) was 65 to 85(%). The size of the sample used for gloss measurement was 5 cm x 10 cm, and the measurement was made by pressing the back side of the sample against a blackboard using the air suction method and measuring three times, and the average value was recorded as the measured 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), electroluminescence displays (organic or inorganic ELDs), micro LED displays, field emission displays (FEDs), touch panels, electronic paper, tablet PCs, etc. It can also be suitably used for image display surfaces in foldable, bendable, or rollable image display devices and touch panels.

Claims

1. An optical laminate in which an antiglare 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 unevenness are measured in an arbitrary 5 μm square area on the surface of the low refractive index layer, The Ra is 4 nm or less, The Rz is 60 nm or less, 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 more and 1600 MPa or less. An optical laminate characterized by:

2. An optical laminate as described in claim 1, wherein the contact angle of the surface of the low refractive index layer with water is 102° or less.

3. An optical laminate described in claim 1 or 2, wherein the low refractive index layer contains hollow silica microparticles.

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

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