Transparent molded body, optical member, and near-infrared sensor cover

Abstract

The purpose of the present invention is to provide a transparent molded body excellent in low reflectivity of light in a near-infrared region and low in angle dependence of reflectance of light in a near-infrared region, an optical member including the transparent molded body, and a near-infrared sensor cover.　This transparent molded body (1) is provided with a transparent base material (10), and an uneven layer (12) formed on at least one surface of the transparent base material (10) and comprising a cured product of a curable composition, the uneven layer (12) having, on the surface thereof, a fine uneven structure in which the interval P between adjacent protrusions (14) is 80-400 nm, the height H of the protrusions (14) of the fine uneven structure is 320 nm or more, and the ratio (height H / interval P) of the height H of the protrusions (14) and the interval P between the adjacent protrusions (14) is 2.0-3.9.

Description

Transparent molded bodies, optical components, and near-infrared sensor covers

[0001] The present invention relates to a transparent molded body, an optical member, and a near-infrared sensor cover, and in particular to a transparent molded body, an optical member, and a near-infrared sensor cover that are suitable for use as a sensor cover for a LiDAR device. This application claims priority based on Japanese Patent Application No. 2024-82221 filed with the Japan Patent Office on May 20, 2024, and Japanese Patent Application No. 2024-157350 filed with the Japan Patent Office on September 11, 2024, the contents of which are incorporated herein by reference.

[0002] A LiDAR (Light Detection and Ranging) device is known as one of the remote sensing technologies using light. The LiDAR device irradiates a target with near-infrared laser light, and the reflected or scattered light returning from the target is detected by a photodetector, thereby measuring the distance to the target. Near-infrared laser light often has wavelengths in the near-infrared region, such as 905 nm, 1310 nm, or 1550 nm.

[0003] In a LiDAR device, near-infrared laser light emitted from a light source passes through a near-infrared sensor cover, is reflected by an object, and then passes through the near-infrared sensor cover again to reach a photodetector. Therefore, in order to accurately detect more distant objects using a LiDAR device, it is necessary to increase the amount of light returning to the photodetector by reducing reflection from the near-infrared sensor cover. Patent Document 1 discloses an optical cover component for a LiDAR device. The optical cover component in Patent Document 1 includes a substrate and a near-infrared anti-reflection coating, and the near-infrared anti-reflection coating has at least two layers: a high refractive index layer and a low refractive index layer.

[0004] JP 2023-173264 A

[0005] However, in conventional optical cover parts such as those described in Patent Document 1, it is necessary to change the film thickness of the near-infrared anti-reflection film from the center to the outside of the cover, which is technically difficult. In addition, the low reflectivity of near-infrared laser light is not sufficient, and the reflectance changes depending on the angle of incidence of the incident light (angle dependency), so further technical improvements are required.

[0006] The main object of the present invention is to provide a transparent molded body that has excellent low reflectivity of light in the near-infrared region and small angular dependency of reflectance of light in the near-infrared region, and an optical component and a near-infrared sensor cover that include the transparent molded body.

[0007] Preferred embodiments of the present invention include, but are not limited to, the following. [1] A transparent molded article comprising: a transparent substrate; and a concavo-convex layer formed on at least one surface of the transparent substrate and made of a cured product of a curable composition, wherein the concavo-convex layer has a fine concavo-convex structure on its surface, with a spacing P between adjacent convex portions of 80 nm to 400 nm, and the height H of the convex portions of the fine concavo-convex structure is 320 nm or more, and the ratio of the height H of the convex portions to the spacing P between adjacent convex portions (height H / spacing P) is 2.0 to 3.9. [2] The transparent molded article according to [1], wherein the surface of the concavo-convex layer having the fine concavo-convex structure has an average reflectance of 10% or less at an incident angle of 70° for light with a wavelength of 850 to 950 nm. [3] The transparent molded article according to [1] or [2], wherein the surface of the concavo-convex layer having the fine concavo-convex structure has an average reflectance of 0.5% or less at an incident angle of 5° for light with a wavelength of 850 to 950 nm. [4] The transparent molded body according to any one of [1] to [3], wherein the surface of the uneven layer having the fine uneven structure has an average reflectance of 1.0% or less for light with an incident angle of 5° of 1,500 to 1,600 nm. [5] The transparent molded body according to any one of [1] to [4], wherein the elastic modulus of the convex portions of the fine uneven structure is 500 MPa or more and 3,000 MPa or less. [6] The transparent molded body according to any one of [1] to [5], wherein the water contact angle of the convex portions of the fine uneven structure is 25° or less. [7] An optical member comprising the transparent molded body according to any one of [1] to [6]. [8] A near-infrared sensor cover comprising the transparent molded body according to any one of [1] to [6]. [9] The near-infrared sensor cover according to [8], which has a flat shape.

[10] The near-infrared sensor cover according to [8], which has a curved shape with a bending radius of 200 mm or more.

[0008] According to the present invention, there are provided a transparent molded body that has excellent low reflectivity of light in the near-infrared region and small angular dependency of reflectance of light in the near-infrared region, and an optical component and a near-infrared sensor cover that include the transparent molded body.

[0009] FIG. 1 is a cross-sectional view schematically illustrating an example of a transparent molded body. FIG. 2 is an explanatory diagram illustrating an example of a method for producing a transparent molded body. FIG. 3 is a graph showing the reflectance of light at an incident angle of 5° in Examples 1, 2, and 4 and Comparative Examples 1 and 2. The horizontal axis represents wavelength and the vertical axis represents reflectance. FIG. 4 is a graph showing the reflectance of light at an incident angle of 30° in Examples 1, 2, and 4 and Comparative Examples 1 and 2. The horizontal axis represents wavelength and the vertical axis represents reflectance. FIG. 5 is a graph showing the reflectance of light at an incident angle of 50° in Examples 1, 2, and 4 and Comparative Examples 1 and 2. The horizontal axis represents wavelength and the vertical axis represents reflectance. FIG. 6 is a graph showing the reflectance of light at an incident angle of 70° in Examples 1, 2, and 4 and Comparative Examples 1 and 2. The horizontal axis represents wavelength and the vertical axis represents reflectance. FIG. 7 is a graph showing the reflectance of light at an incident angle of 5° in Examples 1, 4, 5, and 6 and Comparative Example 4. The horizontal axis represents wavelength and the vertical axis represents reflectance. FIG. 8 shows a graph of the reflectance of light at an incident angle of 30° in Examples 1, 4, 5, 6, and Comparative Example 4. The horizontal axis represents wavelength, and the vertical axis represents reflectance. FIG. 9 shows a graph of the reflectance of light at an incident angle of 50° in Examples 1, 4, 5, 6, and Comparative Example 4. The horizontal axis represents wavelength, and the vertical axis represents reflectance. FIG. 10 shows a graph of the reflectance of light at an incident angle of 70° in Examples 1, 4, 5, 6, and Comparative Example 4. The horizontal axis represents wavelength, and the vertical axis represents reflectance. FIG. 11 shows a graph of the reflectance of light at an incident angle of 5° in Examples 3, 7, 8, 9, and Comparative Example 3. The horizontal axis represents wavelength, and the vertical axis represents reflectance. FIG. 12 shows a graph of the reflectance of light at an incident angle of 30° in Examples 3, 7, 8, 9, and Comparative Example 3. The horizontal axis represents wavelength, and the vertical axis represents reflectance. Fig. 13 shows a graph of the reflectance of light at an incident angle of 50° in Examples 3, 7, 8, and 9 and Comparative Example 3. The horizontal axis represents wavelength and the vertical axis represents reflectance. Fig. 14 shows a graph of the reflectance of light at an incident angle of 70° in Examples 3, 7, 8, and 9 and Comparative Example 3. The horizontal axis represents wavelength and the vertical axis represents reflectance.

[0010] In this specification, the following terms have the following meanings: "(Meth)acrylate" is a general term for acrylate and methacrylate; "Active energy rays" means visible light, ultraviolet light, electron beams, plasma, heat rays (infrared rays, etc.), etc.; "Transparent" means that the transmittance of light at least at any one of wavelengths 905 nm, 1310 nm, and 1550 nm is 70% or more.

[0011] <Transparent Molded Article> A transparent molded article according to an embodiment includes a transparent substrate and a concave-convex layer formed on at least one surface of the transparent substrate and made of a cured product of a curable composition. The concave-convex layer has a fine concave-convex structure on its surface, in which the spacing P between adjacent convex portions is 80 nm or more and 400 nm or less. The height H of the convex portions of the fine concave-convex structure is 320 nm or more. The ratio of the height H of the convex portions to the spacing P between adjacent convex portions (height H / spacing P) is 2.0 to 3.9.

[0012] In the transparent molded body according to the embodiment, the uneven layer may be provided on only one surface of the transparent substrate, or the uneven layer may be provided on both surfaces of the transparent substrate.

[0013] Fig. 1 is a cross-sectional view showing a schematic example of a transparent molded body. The dimensions of the drawings shown in the following description are merely examples, and the present invention is not necessarily limited thereto. The present invention can be practiced with appropriate modifications within the scope of the present invention.

[0014] The transparent molded body 1 illustrated in FIG. 1 includes a transparent substrate 10 and an uneven layer 12 formed on one surface of the transparent substrate 10. In another example, one or more intermediate layers may be sandwiched between the transparent substrate 10 and the uneven layer 12 formed on its surface for the purpose of imparting adhesion. The uneven layer 12 has a fine uneven structure on the surface opposite the transparent substrate 10. In the fine uneven structure, the spacing P between adjacent convex portions 14 is 80 nm or more and 400 nm or less. The height H of the convex portions 14 in the fine uneven structure is 320 nm or more. The ratio of the height H of the convex portions 14 to the spacing P between adjacent convex portions 14 (height H / spacing P) is 2.0 to 3.9.

[0015] [Transparent Substrate] Examples of the transparent substrate 10 include films and sheets that can transmit light. Examples of materials for the transparent substrate 10 include glass, acrylic resins, polycarbonate resins, styrene resins, polyester resins, cellulose resins (such as triacetyl cellulose), polyolefin resins, alicyclic polyolefin resins, polyimide resins, silicone resins, and fluorine-based resins. The material for the transparent substrate 10 may be used alone or in combination of two or more. Polyester resins are preferred because of their excellent strength. Cellulose resins are preferred because they reduce the difference in refractive index between the transparent substrate 10 and the uneven layer 12. The transparent substrate 10 may be a single layer or a laminate of multiple layers.

[0016] The thickness of the transparent substrate 10 is not particularly limited and can be, for example, 10 μm or more, 20 μm or more, 30 μm or more, or 40 μm or more, and can be 500 μm or less, 300 μm or less, 200 μm or less, or 100 μm or less. The preferred lower and upper limits of the thickness of the transparent substrate 10 can be arbitrarily combined, and for example, 10 μm or more and 500 μm or less is preferred, 20 μm or more and 300 μm or less is more preferred, 20 μm or more and 200 μm or less is even more preferred, and 30 μm or more and 100 μm or less is particularly preferred.

[0017] [Uneven Layer] The uneven layer 12 is a layer made of a cured product of an active energy ray-curable resin composition, and has a fine uneven structure, a so-called moth-eye structure, on its surface, in which multiple convex portions 14 are arranged at intervals equal to or less than the wavelength of visible light. The moth-eye structure is known to be an effective anti-reflection measure because the refractive index of the moth-eye structure increases continuously from the refractive index of air to the refractive index of the material of the moth-eye structure. The convex portions formed on the surface of the uneven layer 12 are preferably formed by transferring multiple pores (concave portions) on the surface of anodized alumina. Examples of the shape of the multiple convex portions 14 include a substantially conical shape, a bell shape, and a pyramidal shape.

[0018] The height H of the convex portions 14 is 320 nm or more, preferably 350 nm or more, more preferably 450 nm or more, even more preferably 500 nm or more, and particularly preferably 600 nm or more. The upper limit of the height H of the convex portions 14 may generally be 1,000 nm or less, preferably 800 nm or less, and more preferably 700 nm or less. In the transparent molding die 1 illustrated in FIG. 1, the height H of the convex portions 14 is 320 nm or more, so the reflectance of light in the near-infrared region is low. If the height H of the convex portions 14 is 1,000 nm or less, the mechanical strength of the convex portions 14 is good. The height H of the convex portions 14 is obtained by observing a cross section of the uneven layer 12 cut in the thickness direction with an electron microscope. The height H is measured at any 10 points on the convex portions 14, and the average of these measured values ​​is obtained.

[0019] The spacing P between adjacent convex portions 14 can also be said to be the average period (pitch) between the convex portions 14. The spacing P between adjacent convex portions 14 is 400 nm or less, preferably 300 nm or less, more preferably 250 nm or less, and even more preferably 200 nm or less. Because the convex portions 14 are easily formed and the tips of adjacent convex portions 14 are easily prevented from joining together, the spacing P between adjacent convex portions 14 is 80 nm or more, preferably 100 nm or more, more preferably 130 nm or more, and even more preferably 140 nm or more. The preferred lower and upper limits of the spacing P between adjacent convex portions 14 can be arbitrarily combined; for example, 80 nm or more and 300 nm or less are preferred, 130 nm or more and 400 nm or less are more preferred, 130 nm or more and 300 nm or less are even more preferred, 130 nm or more and 250 nm or less are even more preferred, and 140 nm or more and 200 nm or less are particularly preferred. The distance P between adjacent convex portions 14 is obtained by observing with an electron microscope a cross section of the concave-convex layer 12 cut in the thickness direction. The distance P between adjacent convex portions 14 (the distance from the center of a convex portion 14 to the center of an adjacent convex portion 14) is measured at any 10 points, and the average value of these measured values ​​is obtained.

[0020] The ratio of the height H of the protrusions 14 to the spacing P between adjacent protrusions 14 (height H / spacing P) is 2.0 to 3.9, preferably 2.2 or more, more preferably 2.5 or more, even more preferably 3.0 or more, and particularly preferably 3.5 or more. If (height H / spacing P) is 2.0 or more, the reflectance of light in the near-infrared region decreases. If (height H / spacing P) is 3.9 or less, coalescence, in which the tips of adjacent protrusions 14 join together, can be suppressed.

[0021] The average reflectance of light with a wavelength of 850 to 950 nm at an incident angle of 70° on the surface having the microrelief structure of the uneven layer 12 is preferably 10% or less. A transparent molded body 1 that satisfies this condition has excellent low reflectivity for light in the near-infrared region and small angle dependency of the reflectance of light in the near-infrared region. Hereinafter, the average reflectance of light with a wavelength of 850 to 950 nm at an incident angle of 70° will be referred to as the "900 nm reflectance at an incident angle of 70°," and the same applies to average reflectances at other incident angles. The 900 nm reflectance at an incident angle of 70° is preferably 10% or less, more preferably 8% or less, and even more preferably 6% or less.

[0022] The 900 nm reflectance at an incident angle of 5° is preferably 0.5% or less, more preferably 0.4% or less, even more preferably 0.3% or less, and particularly preferably 0.2% or less. The 900 nm reflectance at an incident angle of 30° is preferably 0.5% or less, more preferably 0.4% or less, even more preferably 0.3% or less, and particularly preferably 0.2% or less. The 900 nm reflectance at an incident angle of 50° is preferably 1.5% or less, more preferably 1.0% or less, even more preferably 0.8% or less, and particularly preferably 0.5% or less. The 900 nm reflectance at an incident angle of 70° is preferably 10% or less, more preferably 8% or less, even more preferably 6% or less, and particularly preferably 4% or less.

[0023] The average reflectance of light with a wavelength of 1500 to 1600 nm at an incident angle of 5° on the surface having the fine uneven structure of the uneven layer 12 (hereinafter also referred to as "1550 nm reflectance at an incident angle of 5°") is preferably 1.0% or less, more preferably 0.8% or less, even more preferably 0.6% or less, and particularly preferably 0.4% or less.

[0024] The average reflectance of light with a wavelength of 1250 to 1350 nm at an incident angle of 5° on the surface having the fine uneven structure of the uneven layer 12 (hereinafter also referred to as "1300 nm reflectance at an incident angle of 5°") is preferably 1.0% or less, more preferably 0.8% or less, even more preferably 0.6% or less, and particularly preferably 0.4% or less.

[0025] The 900 nm reflectance at incident angles of 5°, 30°, 50°, and 70°, the 1300 nm reflectance at an incident angle of 5°, and the 1550 nm reflectance at an incident angle of 5° can each be adjusted by adjusting the height H of the convex portions in the fine concave-convex structure. For example, by making the convex portions in the fine concave-convex structure taller, the 900 nm reflectance at incident angles of 5°, 30°, 50°, and 70°, the 1300 nm reflectance at an incident angle of 5°, and the 1550 nm reflectance at an incident angle of 5° tend to become smaller.

[0026] As shown in Fig. 1, when a cross section of the uneven layer 12 cut in the thickness direction is observed with an electron microscope, if the tip of the convex portion 14 is flat, the width of the flat surface is taken as the width TW of the tip of the convex portion 14. On the other hand, if the tip of the convex portion 14 is curved, the width at the inflection point where the side of the convex portion 14 changes into the curved surface at the tip is taken as the width TW of the tip of the convex portion 14. If the tip of the convex portion 14 is sharp, that is, if there is neither a flat surface nor a curved surface, the width TW of the tip of the convex portion 14 is 0. Furthermore, the width of the convex portion 14 at the reference plane is taken as the width BW of the bottom of the convex portion 14.

[0027] Since reflection at the tips of the fine uneven layer can be suppressed, the ratio (TW / BW) of the width TW of the tips of the convex portions 14 of the fine uneven structure of the uneven layer 12 to the width BW of the bottom of the convex portions 14 is preferably less than 0.30, more preferably 0.25 or less, and even more preferably 0.20 or less. Since the scratch resistance of the convex portions is excellent, TW / BW is preferably 0.10 or more, more preferably 0.15 or more. The preferred lower and upper limits of TW / BW can be arbitrarily combined, and for example, 0.10 or more but less than 0.30 is preferred, 0.15 or more but 0.25 is more preferred, and 0.15 or more but 0.20 is even more preferred.

[0028] The difference in refractive index between the uneven layer 12 and the transparent substrate 10 is preferably 0.20 or less, more preferably 0.10 or less, and even more preferably 0.05 or less. When the difference in refractive index between the uneven layer 12 and the transparent substrate 10 is equal to or less than the upper limit, reflection at the interface between the uneven layer 12 and the transparent substrate 10 is easily suppressed. When the thickness of the uneven layer 12 is 10 μm or less, interference due to reflection at the interface between the uneven layer 12 and the transparent substrate 10 is easily observed. However, the smaller the difference in refractive index between the uneven layer 12 and the transparent substrate 10, the more the amplitude of reflected light can be suppressed. Here, the "thickness of the uneven layer 12" refers to the shortest distance from the tip of the convex portion 14 of the fine uneven structure to the interface between the uneven layer 12 and the transparent substrate 10. The refractive index is measured at a wavelength of 1,550 nm.

[0029] When an intermediate layer is sandwiched between the uneven layer 12 and the transparent substrate 10, the difference in refractive index between the uneven layer 12 and the transparent substrate 10 is preferably 0.20 or less, more preferably 0.10 or less, and even more preferably 0.05 or less. When the refractive index difference is below the upper limit, reflection at the interface is easily suppressed. When the thickness of the intermediate layer is 10 μm or less, interference due to reflection at the interface is easily observed, but the smaller the difference in refractive index between the uneven layer 12 and the transparent substrate 10, the easier it is to suppress the amplitude of reflected light. Here, the "thickness of the intermediate layer" refers to the shortest distance from the interface between the uneven layer 12 and the intermediate layer to the interface between the intermediate layer and the transparent substrate 10. The refractive index is measured at a wavelength of 1,550 nm.

[0030] In order to reduce the difference between the refractive index of the uneven layer 12 and the refractive index of the transparent substrate 10, for example, the material of the transparent substrate 10 or the polymerizable compound of the curable resin composition for forming the uneven layer 12 may be appropriately selected. The refractive index of the uneven layer 12 may be higher or lower than the refractive index of the transparent substrate 10, and is not particularly limited.

[0031] The elastic modulus of the material forming the convex portions 14 of the fine uneven structure is preferably 500 MPa or more, more preferably 800 MPa or more, even more preferably 1,000 MPa or more, even more preferably 1,500 MPa or more, and particularly preferably 2,000 MPa or more. The elastic modulus of the convex portions 14 is preferably 3,000 MPa or less, more preferably 2,700 MPa or less, even more preferably 2,500 MPa or less, and particularly preferably 2,200 MPa or less. If the elastic modulus of the convex portions is within the above range, the releasability from the mold when forming the uneven layer 12 is improved. Furthermore, coalescence is easily suppressed, the reflectance on the surface having the fine uneven structure of the uneven layer 12 can be reduced, and the water contact angle can also be reduced. The preferred lower and upper limits of the elastic modulus of the protrusions 14 can be arbitrarily combined, and are, for example, preferably 500 MPa to 3,000 MPa, more preferably 800 MPa to 2,700 MPa, even more preferably 1,000 MPa to 2,500 MPa, and particularly preferably 1,500 MPa to 2,200 MPa.

[0032] The elastic modulus of the material forming the convex portions 14 is the value of the composite elastic modulus obtained by performing an indentation test on the surface of the fine concave-convex structure using a nanoindenter equipped with a conical indenter at 25°C. In order to minimize the influence of air, the indentation test needs to be performed at an indentation depth of at least the height H of the convex portions 14 of the fine concave-convex structure. The indentation test is preferably performed at an indentation depth equal to or greater than the height H of the convex portions 14. From the viewpoint of reducing the influence of the transparent substrate 10 on the composite elastic modulus, the indentation depth is preferably 50% or less of the layer thickness of the concave-convex layer 12, more preferably 20% or less, and even more preferably 10% or less.

[0033] It is known that superhydrophilicity can be achieved if the surface has a fine uneven structure (moth-eye structure) and is formed from a hydrophilic material. The water contact angle of the surface of the uneven layer 12 made of a hydrophilic material is preferably 25° or less, more preferably 20° or less, and even more preferably 10° or less. If the water contact angle is 25° or less, dirt adhering to the surface is washed away with water and oil stains are less likely to adhere, thereby exhibiting sufficient anti-fouling properties. If the water contact angle is 25° or less, even if water adheres, it spreads without forming droplets, preventing fogging and exhibiting anti-fogging properties. In particular, if the water contact angle is 10° or less, when the transparent molded article is used in a LiDAR device, fogging under temperature changes and high humidity environments can be suppressed, effectively suppressing a decrease in detection sensitivity.

[0034] In particular, by setting the height H of the convex portions 14 of the fine concave-convex structure to 320 nm or more and setting the ratio (TW / BW) of the width TW of the tip of the convex portions 14 of the fine concave-convex structure of the concave-convex layer 12 to the width BW of the bottom of the convex portions 14 to be less than 0.30, the water contact angle on the surface of the concave-convex layer 12 can be further reduced.

[0035] The water contact angle of the surface of the uneven layer 12 is preferably 3° or more in order to prevent deformation of the fine uneven structure due to water absorption by the uneven layer 12 and the resulting increase in reflectance.

[0036] [Active Energy Ray-Curable Resin Composition] The active energy ray-curable resin composition preferably contains a polymerizable compound and a polymerization initiator.

[0037] (Polymerizable Compound) Examples of the polymerizable compound include a monomer, oligomer, or reactive polymer having at least one of a radical polymerizable bond and a cation polymerizable bond in the molecule. The active energy ray-curable resin composition may contain a non-reactive polymer or an active energy ray sol-gel reactive composition.

[0038] Examples of the monomer having a radically polymerizable bond in the molecule include monofunctional monomers and polyfunctional monomers. Examples of monofunctional monomers include (meth)acrylate derivatives such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, alkyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, isobornyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, allyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, and 2-ethoxyethyl (meth)acrylate; Examples of the monofunctional monomer include (meth)acrylic acid, (meth)acrylonitrile, styrene derivatives such as styrene and α-methylstyrene, and (meth)acrylamide derivatives such as (meth)acrylamide, N-dimethyl(meth)acrylamide, N-diethyl(meth)acrylamide, and dimethylaminopropyl(meth)acrylamide. One type of monofunctional monomer may be used alone, or two or more types may be used in combination.

[0039] Examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, isocyanuric acid ethylene oxide modified di(meth)acrylate, triethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,3-butylene Glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, 2,2-bis(4-(meth)acryloxypolyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxyethoxyphenyl)propane, 2,2-bis(4-(3-(meth)acryloxy-2-hydroxypropoxy)phenyl)propane, 1,2-bis(3-(meth)acryloxy-2-hydroxypropoxy)ethane, 1,Bifunctional monomers such as 4-bis(3-(meth)acryloxy-2-hydroxypropoxy)butane, dimethyloltricyclodecane di(meth)acrylate, ethylene oxide adduct di(meth)acrylate of bisphenol A, propylene oxide adduct di(meth)acrylate of bisphenol A, hydroxypivalic acid neopentyl glycol di(meth)acrylate, divinylbenzene, and methylenebisacrylamide; trifunctional monomers such as pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide-modified tri(meth)acrylate, trimethylolpropane propylene oxide-modified triacrylate, trimethylolpropane ethylene oxide-modified triacrylate, and isocyanuric acid ethylene oxide-modified tri(meth)acrylate; Examples of the polyfunctional monomer include tetrafunctional or higher monomers such as dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane tetraacrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol ethoxy tetra(meth)acrylate, and ethylene oxide-modified dipentaerythritol hexaacrylate; difunctional or higher urethane acrylates; and difunctional or higher polyester acrylates. One type of polyfunctional monomer may be used alone, or two or more types may be used in combination.

[0040] Examples of the monomer having a cationically polymerizable bond include monomers having an epoxy group, an oxetanyl group, an oxazolyl group, a vinyloxy group, etc. One type of monomer having a cationically polymerizable bond may be used alone, or two or more types may be used in combination. As the monomer having a cationically polymerizable bond, a monomer having an epoxy group is particularly preferred.

[0041] Examples of oligomers or reactive polymers include unsaturated polyesters such as condensates of unsaturated dicarboxylic acids and polyhydric alcohols, polyester (meth)acrylates, polyether (meth)acrylates, polyol (meth)acrylates, epoxy (meth)acrylates, urethane (meth)acrylates, cationically polymerizable epoxy compounds, and homopolymers or copolymers of the above-mentioned monomers having radically polymerizable bonds in their side chains. One type of oligomer or reactive polymer may be used alone, or two or more types may be used in combination.

[0042] Examples of non-reactive polymers include acrylic resins, styrene resins, polyurethanes, cellulose resins, polyvinyl butyral, polyesters, and thermoplastic elastomers. One type of non-reactive polymer may be used alone, or two or more types may be used in combination.

[0043] Examples of the active energy ray sol-gel reactive composition include an alkoxysilane compound and an alkyl silicate compound. One type of active energy ray sol-gel reactive composition may be used alone, or two or more types may be used in combination.

[0044] The alkoxysilane compound may be a compound represented by the following formula (1): １ ｘ Si(OR ２ ) ｙ ...(1) In formula (1), R １ , R ２ each independently represents an alkyl group having 1 to 10 carbon atoms, and x and y represent integers that satisfy the relationship x+y=4.

[0045] Examples of alkoxysilane compounds include tetramethoxysilane, tetra-i-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-t-butoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, trimethylpropoxysilane, and trimethylbutoxysilane.

[0046] The alkyl silicate compound may be a compound represented by the following formula (2): ３ O[Si(OR ５ ) (OR ６ ) O] ｚ R ４ ...(2) In formula (2), R ３ ~R ６ each independently represents an alkyl group having 1 to 5 carbon atoms, and z represents an integer of 3 to 20.

[0047] Examples of alkyl silicate compounds include methyl silicate, ethyl silicate, isopropyl silicate, n-propyl silicate, n-butyl silicate, n-pentyl silicate, and acetyl silicate.

[0048] (Hydrophobic Material) Examples of active energy ray-curable resin compositions that can form the hydrophobic material include compositions that contain at least one of a fluorine-containing compound and a silicone-based compound as a polymerizable compound.

[0049] The fluorine-containing compound is preferably a compound having a fluoroalkyl group represented by the following formula (3): —(CF ２ ) ｎ -X (3) In formula (3), X represents a fluorine atom or a hydrogen atom, and n represents an integer of 1 or more. n is preferably an integer of 1 to 20, more preferably an integer of 3 to 10, and particularly preferably an integer of 4 to 8.

[0050] Examples of the fluorine-containing compound include a fluorine-containing monomer, a fluorine-containing silane coupling agent, a fluorine-containing surfactant, and a fluorine-containing polymer.

[0051] Examples of the fluorine-containing monomer include a fluoroalkyl group-substituted vinyl monomer and a fluoroalkyl group-substituted ring-opening polymerizable monomer.

[0052] Examples of the fluoroalkyl group-substituted vinyl monomer include fluoroalkyl group-substituted (meth)acrylates, fluoroalkyl group-substituted (meth)acrylamides, fluoroalkyl group-substituted vinyl ethers, and fluoroalkyl group-substituted styrenes.

[0053] Examples of the fluoroalkyl group-substituted ring-opening polymerizable monomer include a fluoroalkyl group-substituted epoxy compound, a fluoroalkyl group-substituted oxetane compound, and a fluoroalkyl group-substituted oxazoline compound.

[0054] As the fluorine-containing monomer, a fluoroalkyl group-substituted (meth)acrylate is preferred, and a compound of the following formula (4) is particularly preferred: CH ２ = C(R ７ )C(O)O-(CH ２ ) ｍ -(CF ２ ) ｐ -X...(4) R ７ represents a hydrogen atom or a methyl group, X represents a hydrogen atom or a fluorine atom, m represents an integer of 1 to 6, and p represents an integer of 1 to 20. m is preferably 1 to 3, and more preferably 1 or 2. p is preferably 3 to 10, and more preferably 4 to 8.

[0055] As the fluorine-containing silane coupling agent, a fluoroalkyl group-substituted silane coupling agent is preferred, and a compound of the following formula (5) is particularly preferred. (R ｆ ) ａ R ８ ｂ SiY ｃ ...(5) In formula (5), R ｆ represents a fluorine-substituted alkyl group having 1 to 20 carbon atoms which may have one or more ether bonds or ester bonds, R ８represents an alkyl group having 1 to 10 carbon atoms, Y represents a hydroxyl group or a hydrolyzable group, and a, b, and c represent integers such that a+b+c=4 and a≧1 and c≧1.

[0056] R ｆ Examples of the aryl group include a 3,3,3-trifluoropropyl group, a tridecafluoro-1,1,2,2-tetrahydrooctyl group, a 3-trifluoromethoxypropyl group, and a 3-trifluoroacetoxypropyl group.

[0057] R ８ Examples of the alkyl group include a methyl group, an ethyl group, and a cyclohexyl group.

[0058] Examples of the hydrolyzable group of Y include an alkoxy group, a halogen atom, and R ９ C(O)O, where R ９ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propyloxy group, an i-propyloxy group, a butoxy group, an i-butoxy group, a t-butoxy group, a pentyloxy group, a hexyloxy group, a cyclohexyloxy group, a heptyloxy group, an octyloxy group, a 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, a 3,7-dimethyloctyloxy group, and a lauryloxy group. Examples of the halogen atom include Cl, Br, and I. R ９ Examples of C(O)O include CH ３ C(O)O,C ２ H ５ C(O)O. As for a, b, and c, it is preferable that a=1, b=0, and c=3.

[0059] Examples of fluorine-containing silane coupling agents include 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriacetoxysilane, dimethyl-3,3,3-trifluoropropylmethoxysilane, and tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane.

[0060] Examples of fluorine-containing surfactants include fluoroalkyl group-containing anionic surfactants and fluoroalkyl group-containing cationic surfactants.

[0061] Examples of fluoroalkyl group-containing anionic surfactants include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms or metal salts thereof, disodium perfluorooctanesulfonyl glutamate, sodium 3-[omega-fluoroalkyl(C6 to C11)oxy]-1-alkyl(C3 to C4)sulfonate, sodium 3-[omega-fluoroalkanoyl(C6 to C8)-N-ethylamino]-1-propanesulfonate, fluoroalkyl(C11 to C20)carboxylic acids or metal salts thereof, perfluoroalkanesulfonates, and the like. perfluoroalkyl (C7 to C13) sulfonic acids or metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids or metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N-(2-hydroxyethyl)perfluorooctanesulfonamide, perfluoroalkyl (C6 to C10) sulfonamidopropyl trimethylammonium salts, perfluoroalkyl (C6 to C10)-N-ethylsulfonylglycine salts, and monoperfluoroalkyl (C6 to C16) ethyl phosphate esters.

[0062] Examples of fluoroalkyl group-containing cationic surfactants include fluoroalkyl group-containing aliphatic primary, secondary, or tertiary amine acids, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6 to C10) sulfonamidopropyltrimethylammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, and imidazolinium salts.

[0063] Examples of the fluorine-containing polymer include a polymer of a fluoroalkyl group-containing monomer, a copolymer of a fluoroalkyl group-containing monomer and a poly(oxyalkylene) group-containing monomer, and a copolymer of a fluoroalkyl group-containing monomer and a crosslinkable group-containing monomer. The fluorine-containing polymer may also be a copolymer with other copolymerizable monomers.

[0064] The fluorine-containing polymer is preferably a copolymer of a fluoroalkyl group-containing monomer and a poly(oxyalkylene) group-containing monomer. The poly(oxyalkylene) group is preferably a group represented by the following formula (6): -(OR １０ ) ｑ - ... (6) R １０ represents an alkylene group having 2 to 4 carbon atoms, and q represents an integer of 2 or more.

[0065] R １０ Examples of the group include -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ The poly(oxyalkylene) group includes the same oxyalkylene units (OR １０ ), and may be composed of two or more kinds of oxyalkylene units (OR １０ ) may be composed of two or more kinds of oxyalkylene units (OR １０ The arrangement of the nucleotides may be in blocks or random.

[0066] Examples of silicone compounds include (meth)acrylic acid-modified silicones, silicone resins, and silicone-based silane coupling agents. Examples of (meth)acrylic acid-modified silicones include silicone (di)(meth)acrylates.

[0067] (Hydrophilic Material) As the active energy ray-curable resin composition capable of forming the hydrophilic material, a composition containing 20% ​​by mass or more of a tetrafunctional or higher polyfunctional (meth)acrylate and / or a urethane (meth)acrylate, 20% by mass or more of a difunctional or higher hydrophilic (meth)acrylate and / or a urethane (meth)acrylate, and 0% by mass or more and 20% by mass or less of a monofunctional monomer, relative to the total mass of the polymerizable compounds, is preferred.

[0068] Examples of tetrafunctional or higher polyfunctional (meth)acrylates and urethane (meth)acrylates include ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol ethoxytetra(meth)acrylate, dipentaerythritol hydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified dipentaerythritol hexaacrylate, and urethane acrylates (e.g., Daicel-Cytec products EBECRYL220, EBECRYL1290, EBECRYL1290K, EB EBECRYL5129, EBECRYL8210, EBECRYL8301, KRM8200), polyether acrylates (e.g., EBECRYL81 manufactured by Daicel-Cytec), modified epoxy acrylates (e.g., EBECRYL3416 manufactured by Daicel-Cytec), polyester acrylates (e.g., EBECRYL450, EBECRYL657, EBECRYL800, EBECRYL810, EBECRYL811, EBECRYL812, EBECRYL1830, EBECRYL845, EBECRYL846, EBECRYL1870 manufactured by Daicel-Cytec). The tetrafunctional or higher polyfunctional (meth)acrylate and urethane (meth)acrylate may be used alone or in combination of two or more thereof.

[0069] The proportion of the tetrafunctional or higher polyfunctional (meth)acrylate and / or urethane (meth)acrylate is preferably 20% by mass or more, and from the viewpoint of water resistance and chemical resistance, more preferably 50% by mass or more, particularly preferably 70% by mass or more, based on the total mass of the polymerizable compounds. When the proportion of the tetrafunctional or higher polyfunctional (meth)acrylate and / or urethane (meth)acrylate is equal to or greater than the lower limit, the elastic modulus of the uneven layer 12 is increased, and the effect of suppressing coalescence is easily obtained.

[0070] Examples of difunctional or higher functional hydrophilic (meth)acrylates and urethane (meth)acrylates include (meth)acrylates having long chain polyethylene glycols, such as ARONIX M-240 and ARONIX M260 (manufactured by Toagosei Co., Ltd.), NK Ester AT-20E and NK Ester ATM-35E (manufactured by Shin-Nakamura Chemical Co., Ltd.), polyethylene glycol dimethacrylate, and ethylene oxide-modified dipentaerythritol hexaacrylate. One type of difunctional or higher functional hydrophilic (meth)acrylate may be used alone, or two or more types may be used in combination.

[0071] In a (meth)acrylate having a long-chain polyethylene glycol, the average total number of repeating units of the polyethylene glycol chain present in one molecule is preferably 6 or more, more preferably 9 or more, even more preferably 12 or more, and preferably 40 or less, more preferably 30 or less, and even more preferably 20 or less. When the average repeating units of the polyethylene glycol chain is at least the above-mentioned lower limit, hydrophilicity is sufficient and antifouling properties are improved. When the average repeating units of the polyethylene glycol chain is at most the above-mentioned upper limit, compatibility with polyfunctional (meth)acrylates having tetrafunctionality or more is good and separation of the active energy ray-curable resin composition is unlikely. The preferred lower and upper limits of the average repeating units of the polyethylene glycol chain can be arbitrarily combined; for example, 6 to 40 is preferred, 9 to 30 is more preferred, and 12 to 20 is particularly preferred.

[0072] The proportion of the difunctional or higher hydrophilic (meth)acrylate and / or urethane (meth)acrylate is preferably 20% by mass or more, more preferably 40% by mass or more, based on the total mass of the polymerizable compound. When the proportion of the difunctional or higher hydrophilic (meth)acrylate and / or urethane (meth)acrylate is equal to or greater than the lower limit, sufficient hydrophilicity is obtained, and antifouling properties are improved.

[0073] As the monofunctional monomer, a hydrophilic monofunctional monomer is preferred. Examples of hydrophilic monofunctional monomers include monofunctional (meth)acrylates having a polyethylene glycol chain on an ester group, such as M-20G, M-90G, and M-230G (manufactured by Shin-Nakamura Chemical Co., Ltd.), monofunctional (meth)acrylates having a hydroxyl group on an ester group, such as hydroxyalkyl (meth)acrylates, monofunctional acrylamides, and cationic monomers such as methacrylamide propyl trimethyl ammonium methyl sulfate and methacryloyloxyethyl trimethyl ammonium methyl sulfate. As the monofunctional monomer, viscosity modifiers such as acryloyl morpholine and vinyl pyrrolidone, and adhesion improvers such as acryloyl isocyanates that improve adhesion to transparent substrates may also be used. One type of monofunctional monomer may be used alone, or two or more types may be used in combination.

[0074] The proportion of the monofunctional monomer may be 0% by mass, preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, relative to the total mass of the polymerizable compound. The use of the monofunctional monomer improves adhesion between the transparent substrate and the cured resin. If the proportion of the monofunctional monomer is 20% by mass or less, there is no shortage of polyfunctional (meth)acrylates having tetrafunctional or more or hydrophilic (meth)acrylates having difunctional or more, and sufficient antifouling or scratch resistance is exhibited. The preferred lower and upper limits of the proportion of the monofunctional monomer can be arbitrarily combined, and for example, 0% by mass or more and 20% by mass or less are preferred, and 5% by mass or more and 15% by mass or less are preferred.

[0075] The monofunctional monomer may be blended in the active energy ray-curable resin composition in an amount of 0 to 35% by mass as a low-polymerization polymer obtained by (co)polymerizing one or more types of monofunctional monomer. Examples of the low-polymerization polymer include a 40 / 60 copolymer oligomer of a monofunctional (meth)acrylate having a polyethylene glycol chain on an ester group, such as M-230G (manufactured by Shin-Nakamura Chemical Co., Ltd.), and methacrylamide propyl trimethyl ammonium methyl sulfate (MG Polymer, manufactured by MRC Unitec Co., Ltd.).

[0076] (Polymerization Initiator) When a photocuring reaction is utilized, examples of the photopolymerization initiator include carbonyl compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzil, benzophenone, p-methoxybenzophenone, 2,2-diethoxyacetophenone, α,α-dimethoxy-α-phenylacetophenone, methylphenyl glyoxylate, ethylphenyl glyoxylate, 4,4'-bis(dimethylamino)benzophenone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide; and benzoyldiethoxyphosphine oxide. These photopolymerization initiators may be used alone or in combination of two or more.

[0077] When an electron beam curing reaction is utilized, examples of the polymerization initiator include thioxanthones such as benzophenone, 4,4-bis(diethylamino)benzophenone, 2,4,6-trimethylbenzophenone, methyl orthobenzoylbenzoate, 4-phenylbenzophenone, t-butylanthraquinone, 2-ethylanthraquinone, 2,4-diethylthioxanthone, isopropylthioxanthone, and 2,4-dichlorothioxanthone; acetophenones such as diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; Examples of the polymerization initiator include acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, methylbenzoyl formate, 1,7-bisacridinylheptane, and 9-phenylacridine. One type of polymerization initiator may be used alone, or two or more types may be used in combination.

[0078] When a thermosetting reaction is utilized, examples of the thermal polymerization initiator include organic peroxides such as methyl ethyl ketone peroxide, benzoyl peroxide, dicumyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyoctoate, t-butyl peroxybenzoate, and lauroyl peroxide, azo compounds such as azobisisobutyronitrile, and redox polymerization initiators in which the organic peroxides are combined with amines such as N,N-dimethylaniline and N,N-dimethyl-p-toluidine. One type of thermal polymerization initiator may be used alone, or two or more types may be used in combination.

[0079] The amount of the polymerization initiator used is preferably 0.1 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the polymerizable compound. When the amount of the polymerization initiator used is equal to or more than the lower limit, polymerization easily proceeds. When the amount of the polymerization initiator used is equal to or less than the upper limit, the uneven layer is less likely to be discolored and the mechanical strength is less likely to decrease.

[0080] (Other Components) The active energy ray curable resin composition may contain additives such as antistatic agents, release agents, and fluorine compounds for improving antifouling properties, fine particles, or a small amount of solvent, as necessary. When the active energy ray curable resin composition contains, for example, a (poly)oxyalkylene alkyl phosphate compound as a release agent, the releasability between the cured resin layer, which is the cured product, and the mold is particularly good. In addition, since the load during mold release is extremely low, the damage to the fine uneven structure is small, and as a result, the fine uneven structure of the mold can be transferred efficiently and accurately.

[0081] [Method for Producing Transparent Molded Article] The transparent molded article 1 can be produced by a known production method. Examples include the following methods A1 to A3. Method A1: A method in which a mold having an inverted structure of a microrelief structure on its surface is used to perform injection molding or press molding to directly form a microrelief structure on the surface of a substrate. Method A2: A method in which an active energy ray-curable composition is sandwiched between a mold having an inverted structure of a microrelief structure and a substrate, the active energy ray-curable composition is cured in a state in which it forms a rough layer, and then the rough layer and the mold are separated. Method A3: A method in which an active energy ray-curable composition is sandwiched between a mold having an inverted structure of a microrelief structure and a substrate, the microrelief structure of the mold is transferred to the active energy ray-curable composition, the mold is separated, and the active energy ray-curable composition is cured to form a rough layer. Among the methods for producing a microrelief structure, methods A2 and A3 are preferred, with method A2 being more preferred, due to their excellent transferability of the microrelief structure and excellent flexibility in surface composition.

[0082] For example, a mold having a surface with a plurality of pores (recesses) corresponding to the plurality of protrusions 14 is used, a transparent substrate 10 is superimposed on the surface of the mold, and an active energy ray-curable resin composition is supplied between them. Then, the active energy ray-curable resin composition filled between the surface of the mold and the transparent substrate 10 is irradiated with active energy rays from the transparent substrate 10 side to cure the active energy ray-curable resin composition, thereby forming an uneven layer 12 to which the plurality of pores (recesses) on the surface of the mold have been transferred. The transparent molded body 1 is then peeled off from the mold to obtain the transparent molded body 1.

[0083] Examples of light sources for irradiating active energy rays include high-pressure mercury lamps, metal halide lamps, UV-LED lamps, and electrodeless UV lamps. The irradiation energy amount of the active energy rays is 100 to 10,000 mJ / cm. ２ is preferred.

[0084] Examples of molds include molds having a microrelief structure formed on the surface by lithography, molds having a microrelief structure formed on the surface by laser processing, molds having a microrelief structure formed on the surface by etching a master plate covered with glassy carbon or polyimide with oxygen plasma or the like, molds having anodized porous alumina with multiple pores formed on the surface, and replica molds replicated by electroforming or the like from a mother mold having a microrelief structure. Among these molds, molds having anodized porous alumina with multiple pores formed on the surface are preferred because they have excellent anti-reflection performance and are easy to form large-area microrelief structures at low cost. Examples of mold shapes include flat, belt, and roll shapes. Among these mold shapes, belt and roll shapes are preferred because they allow for continuous transfer of the microrelief structure and are highly productive.

[0085] As the mold, a roll-shaped mold having a plurality of recesses formed on the outer peripheral surface is particularly preferred. A roll-shaped mold allows for a large-area transparent molded body, and the mold is easy to manufacture. As the roll-shaped mold, a mold having anodized alumina on the outer peripheral surface is preferred. Anodized alumina is a porous oxide coating of aluminum (anodized aluminum) and has a plurality of pores (recesses) on the surface.

[0086] (Method for Manufacturing Mold) Examples of methods for manufacturing a mold having anodized alumina on its surface include a method comprising the following steps (a), (b), (c), (d), and (e): Step (a) Anodizing an aluminum substrate in an electrolyte at a constant voltage to form an oxide film; Step (b) Removing the oxide film to form pore initiation points for anodization; Step (c) Anodizing the aluminum substrate again in an electrolyte to form an oxide film with pores at the pore initiation points; Step (d) Enlarging the diameter of the pores; Step (e) Repeating steps (c) and (d).

[0087] As shown in FIG. 2( a), in step (a), the surface of an aluminum substrate 34 is immersed in an electrolyte and anodized under a constant voltage. This forms an oxide film 38 having pores 36 on the surface of the aluminum substrate 34. To prevent "burning" due to excessive current flow, it is preferable to apply a voltage lower than the constant voltage in advance or to alternately apply and stop the voltage. Because this facilitates the formation of highly regular pores 36, the purity of the aluminum substrate 34 is preferably 99% or higher, more preferably 99.5% or higher, and particularly preferably 99.8% or higher. Examples of electrolytes include oxalic acid, malonic acid, and sulfuric acid.

[0088] When oxalic acid or malonic acid is used as the electrolyte, the concentration of oxalic acid or malonic acid is preferably 0.7 M or less. The current value is not too high, and the surface of the oxide film 38 is less likely to become rough. The voltage during anodization is preferably 20 V or more and 200 V or less, more preferably 40 V or more and 150 V or less, and particularly preferably 60 V or more and 100 V or less. As the voltage increases within the above range, the period (pitch) of the pores 36 tends to widen and the pores 36 tend to become deeper. The temperature of the electrolyte is preferably 5°C or more, more preferably 10°C or more, and is preferably 45°C or less, and more preferably 30°C or less. When the temperature of the electrolyte is below the upper limit, the phenomenon known as "burning" is less likely to occur, and pores 36 with excellent regularity are more likely to be formed.

[0089] When sulfuric acid is used as the electrolyte, the concentration of sulfuric acid is preferably 0.7 M or less. If the concentration of sulfuric acid is below the upper limit, the current value does not become too high, and it is easy to maintain a constant voltage. The voltage during anodization is preferably 20 V or more and 100 V or less, and more preferably 60 V or more and 90 V or less. As the voltage increases within the above range, the period (pitch) of the pores 36 tends to widen and the pores 36 tend to become deeper. The temperature of the electrolyte is preferably 5°C or more, more preferably 10°C or more, and is preferably 30°C or less, and more preferably 20°C or less. If the temperature of the electrolyte is below the upper limit, the phenomenon known as "burning" is less likely to occur, and pores 36 with excellent regularity are easily formed.

[0090] As shown in FIG. 2( b), in step (b), the oxide film 38 is removed to form pore generation points 40 for anodizing. One method for removing the oxide film is to dissolve it in a solution that selectively dissolves the oxide film but does not dissolve aluminum. An example of such a solution is a mixture of chromic acid and phosphoric acid. Steps (a) and (b) are preferably performed as appropriate to increase the regularity of the pore arrangement, and can be omitted to shorten the process.

[0091] 2(c), in step (c), the aluminum substrate 34 from which the oxide film 38 has been removed is again immersed in the electrolyte and anodized under a constant voltage to form an oxide film 38 having cylindrical pores 36. The anodization in step (c) may be performed under the same conditions as in step (a). The longer the anodization time, the deeper the pores that can be formed.

[0092] 2(d), in step (d), the pores 36 formed by anodization are enlarged by immersion in a solution that dissolves the oxide film 38. An example of a solution that dissolves the oxide film 38 is an aqueous solution of phosphoric acid with a concentration of about 5% by mass. The longer the treatment time for enlarging the diameter of the pores 36, the larger the pore diameter becomes.

[0093] As shown in Figure 2, in step (e), anodized alumina is formed with pores 36 whose diameters continuously decrease in the depth direction from the openings by repeating the anodization in step (c) and the pore size expansion treatment in step (d). This results in a mold 22 in which anodized alumina having a plurality of pores 36 is formed on the surface. The total number of repetitions of steps (c) and (d) in step (e) is preferably three or more times, more preferably five or more times, and even more preferably six or more times. When steps (a) and (b) are omitted, a mold 22 in which anodized alumina having a plurality of pores 36 is formed on the surface can be obtained by repeating steps (c) and (d).

[0094] The surface of the anodized alumina may be treated with a release agent to facilitate separation from the uneven layer 12. Examples of treatment methods include coating with the release agent and vapor deposition. Examples of release agents that can be used include various waxes such as polyethylene wax and paraffin wax, higher fatty acid alcohols, organopolysiloxanes, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorine-based surfactants, organic carboxylic acids and derivatives thereof, fluorine-based resins, and silicone resins. Among these release agents, (poly)oxyalkylene alkyl phosphate compounds are preferred because of their excellent releasability between the cured product of the curable composition and the mold surface.

[0095] The shape of the pores 36 may be a substantially conical shape, a bell shape, a pyramidal shape, etc. The average period between the pores 36 is equal to or less than the wavelength of visible light, that is, 400 nm or less.

[0096] The depth of the pores 36 is preferably 320 nm or more, more preferably 350 nm or more, even more preferably 400 nm or more, particularly preferably 450 nm or more, and is preferably 1,000 nm or less, more preferably 800 nm or less, even more preferably 700 nm or less, and particularly preferably 600 nm or less. The preferred lower and upper limits of the depth of the pores 36 can be arbitrarily combined, and for example, are preferably 320 to 1,000 nm, more preferably 350 to 800 nm, even more preferably 400 to 700 nm, and particularly preferably 450 to 600 nm.

[0097] <Optical component and near-infrared sensor cover> The optical component according to the embodiment includes a transparent molded body according to the embodiment. The optical component is not particularly limited, but the transparent molded body according to the embodiment has excellent low reflectivity for light in the near-infrared region and also has a small angle dependency of the reflectivity of light in the near-infrared region, making it useful as a near-infrared sensor cover that transmits near-infrared laser light. In particular, by using it as a near-infrared sensor cover for a LiDAR device, which is a component that transmits near-infrared laser light, it is possible to reduce loss due to reflection of near-infrared light incident at a wide angle, and therefore, it is expected that the performance and reliability of the LiDAR device will be improved.

[0098] The near-infrared sensor cover including the transparent molded article according to the embodiment may have a flat shape or a curved shape with a bending radius of 200 mm or more. For example, in a LiDAR device, a near-infrared sensor cover made of the transparent molded article according to the embodiment can be attached to one side of a housing that houses a light source and a scanning mechanism, with the uneven layer facing outward. The near-infrared sensor cover may have a flat shape or a curved shape with a bending radius of 200 mm or more so that the inner surface on which the light source and scanning mechanism are arranged, i.e., the surface on the transparent substrate side, is concave.

[0099] The substrate of the near-infrared sensor cover may be an organic or inorganic material, and is not particularly limited, as long as it is a material that is transmissive to near-infrared rays. The substrate of the near-infrared sensor cover may have a single-layer structure or a multi-layer structure. Examples of organic materials include resins such as acrylic resin, polycarbonate resin, styrene resin, cellulose resin, polyester resin, and polyolefin resin. Examples of inorganic materials include soda-lime glass, aluminosilicate glass, borosilicate glass, and quartz glass. The glass may be chemically strengthened. Soda-lime glass and aluminosilicate glass are preferred because of their excellent near-infrared transmittance. Polycarbonate resin is preferred because of its excellent near-infrared transmittance and impact resistance. Acrylic resin is particularly preferred because of its excellent near-infrared transmittance, impact resistance, and surface hardness.

[0100] The substrate may be configured to block visible light, which refers to a wavelength of 400 to 800 nm. Blocking visible light prevents the sensor from malfunctioning and makes the sensor less noticeable from the outer surface of the near-infrared sensor cover, thereby adding a decorative element to the design.

[0101] The substrate may contain a colorant to block visible light. The colorant may be any coloring material such as a pigment or a dye, but a pigment is preferably used. Examples of black colorants include carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, pine soot, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complexes, composite oxide-based black pigments, and anthraquinone-based organic black pigments.

[0102] The surface of the substrate may have a functional coating layer for anti-fouling, anti-snow, anti-fogging, etc. The anti-fouling, anti-snow, and anti-snow coating layer may be on the inner surface where the light source and scanning mechanism are located, on the outer surface, or on both surfaces, but it is preferable to have it on the outer surface because it is more effective when exposed to the outside air. The coating layer may be either hydrophilic or hydrophobic. If it is hydrophilic, it can provide anti-fogging properties, and if it is water-repellent, it can repel water and snow. Hydrophilic refers to a contact angle with water of 40° or less, and water-repellent refers to a contact angle with water of 90° or more.

[0103] A heater may be provided on the surface of the substrate. By providing a heater, snow can be quickly removed from the sensor cover surface. The heater may be located on the inner surface where the light source and scanning mechanism are located, or on the outer surface, but it is preferable to have the heater on the inner surface to prevent damage to the heater due to external foreign matter. Examples of heaters include film heaters. Examples include those made of carbon nanotubes, indium tin oxide, aluminum, copper, etc.

[0104] The transparent molded article according to the embodiment can be attached to the substrate of the sensor cover with the uneven layer facing outward to achieve low reflectivity. If a coating layer or heater is provided on the substrate, the uneven layer can be attached to the substrate with the uneven layer facing outward to reduce reflectivity.

[0105] A suitable example of a configuration for the near-infrared sensor cover is one in which a film heater is provided on the inner substrate surface where the light source and scanning mechanism are housed, a transparent molded body according to the embodiment is further provided on top of that, and a functional coating layer is provided on the outer substrate surface opposite the surface where the light source and scanning mechanism are housed.

[0106] The method for attaching the transparent molded article according to the embodiment is not particularly limited, and examples thereof include a method using an adhesive layer. The adhesive layer can be formed, for example, by curing an adhesive composition. A suitable adhesive composition includes an acrylic resin. The acrylic resin is not particularly limited, and various acrylic resins can be used. In order to be applied to the curved surface of an optical component, the adhesive composition may be cured in two or more stages, i.e., may exhibit multi-stage curing properties. The adhesive layer may have the function of blocking visible light. Another attachment method includes a method of producing the transparent molded article according to the embodiment using a film heater as the transparent substrate. Except for using a film heater as the transparent substrate, the transparent molded article can be produced using the manufacturing method A2 or A3 described above.

[0107] Hereinafter, the embodiments will be described in more detail with reference to examples, but the present invention is not limited to the following description in any way.

[0108] <Measurement Method> (Dimensions of Microrelief Structure) Platinum was vapor-deposited on the surface of an antireflection film having a microrelief structure (moth-eye structure). The surface having the microrelief structure was observed using a scanning electron microscope (JEOL Ltd., "JSM-7400F") at an acceleration voltage of 3.00 kV. From the obtained image, the period of the convex portions (the spacing P between convex portions, or pitch), the height H of the convex portions, and the ratio of the width TW of the tip of the convex portion to the width BW of the base of the convex portion (TW / BW) were measured at 10 locations, and the average values ​​were calculated. Using the electron microscope, the areas where the tips of multiple convex portions merged into one, i.e., coalescence, was evaluated according to the following criteria: Good: No coalescence occurred in 70% or more of all convex portions. Poor: Coalescence occurred in 30% or more of all convex portions.

[0109] (Reflectance) An anti-reflection film having a fine uneven structure was attached to one side of a black acrylic resin plate (trade name "Acrylite EX502", manufactured by Mitsubishi Chemical Corporation) via an adhesive layer. At this time, the anti-reflection film and the black acrylic resin plate were attached with the surface opposite to the surface having the fine uneven structure facing the black acrylic resin plate. Thereafter, using a spectrophotometer (manufactured by Agilent, "Cary-7000"), the specular reflectance of light in the wavelength range of 300 to 1700 nm on the surface having the fine uneven structure was measured under conditions of incident angles of 5 °, 30 °, 50 °, and 70 °. The average reflectance over a wavelength range of 850 to 950 nm was recorded as "900 nm reflectance", the average reflectance over a wavelength range of 1250 to 1350 nm was recorded as "1300 nm reflectance", and the average reflectance over a wavelength range of 1500 to 1600 nm was recorded as "1550 nm reflectance". The results are shown in Table 1.

[0110] (Elastic Modulus) An anti-reflective film having a micro-relief structure was attached to one side of a glass slide (trade name "S9112", manufactured by Matsunami Glass Industry Co., Ltd.) via an adhesive layer. The anti-reflective film and glass slide were attached with the side opposite to the side having the micro-relief structure facing the glass slide. With the film attached to the glass slide, an average value of the composite elastic modulus was calculated from data obtained by an instrumented indentation test using a nanoindenter (manufactured by Bruker Japan, "TI980") under the following measurement conditions and analysis method. The instrumented indentation test is a method in which mechanical quantities such as the elastic modulus are calculated from the data obtained by continuously measuring the load and displacement during the process of indenting and unloading an indenter (load-displacement curve). The composite elastic modulus refers to an elastic modulus that includes information on the hardness of the indenter.

[0111] Measurement conditions: Measurement temperature: 25°C Indenter: conical diamond indenter (tip radius: 8.9 μm, manufacturer number: TI-0227) Pre-Load: 0.5 μN Lift Height: 100 nm to 150 nm Machine compliance: 0.50 to 0.54 nm / mN Loading time: 5 sec Holding time: 2 sec Unloading time: 5 sec Measurement mode: load control Maximum load setting value: A preliminary test was performed on the sample by changing the maximum load setting value, and the load at which the maximum indentation depth of the probe became the protrusion height of the fine uneven structure + 50 to 100 nm was determined.

[0112] Analysis method: Numerical processing was performed using the software (Triboscan 10.2.0.2) provided with the device, and the composite modulus was calculated after zero-point correction. The average value was calculated from the composite modulus data obtained by conducting tests at 40 locations (30 μm intervals). During the numerical analysis of the composite modulus, the Area Function required for correcting the indenter shape was created using the measurement results of fused quartz measured at a maximum load setting of 10 to 10,000 μN. The Area Function is expressed by the following formula:

[0113]

[0114] In the above formula, A is the contact cross-sectional area, h ｃ is the contact depth. ｃ is a value obtained from the load-displacement curve obtained by measuring fused silica. In the case of a conical indenter, C in the above equation ０ is fixed at -3.1416, and C １ ~C ５ The value of was obtained by fitting the measurement results of fused quartz with the above equation using the software attached to the instrument.

[0115] Furthermore, in the indentation test, the influence of deformation of the measuring device itself must be corrected using the machine compliance value. The machine compliance was obtained by the following procedure.

[0116] Step 1: Using a Berkovich indenter (manufacturer number: TI-0039), the area function was calculated using the measurement results of fused quartz measured at a maximum load setting of 10 to 10,000 μN. In the case of a Berkovich indenter, C ０ is fixed at 24.5, and C １ ~C ５ The value of was obtained by fitting the measurement results of fused silica with the above formula using the software provided with the device. - Step 2: Using the software provided with the device, the load-displacement curves of the fused silica measured in Step 1 with a maximum load setting of 5,000 to 10,000 μN were analyzed using the Area Function created in Step 1. - Step 3: Using the software provided with the device, the machine compliance was obtained from the analysis results of Step 2.

[0117] Zero point correction is the determination of the point at which the indenter begins to press into the sample (hereafter referred to as the zero point). The horizontal region was taken as the data point group for zero load, and the point at which the indenter begins to press into the sample (the point at which a positive load begins to be applied) was taken as the zero point.

[0118] (Water contact angle) An anti-reflective film having a micro-convexo-concave structure was attached to one side of a glass slide (trade name "S9112", manufactured by Matsunami Glass Industry Co., Ltd.) via an adhesive layer. At this time, the anti-reflective film and the glass slide were attached with the side opposite to the side having the micro-convexo-concave structure of the anti-reflective film facing the glass slide. Then, using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., "DM-501"), distilled water was placed in a plastic syringe, and a stainless steel needle (22G) was attached to the tip and dropped onto the surface having the micro-convexo-concave structure (amount of water dropped: 1 μL, temperature: 25 ° C.). The contact angle after 7 seconds of dropping the water was measured at any 10 points on the surface having the micro-convexo-concave structure. The average value of these was taken as the water contact angle.

[0119] (Refractive index) Measurements were made using a prism coupler (manufactured by Metricon) at wavelengths of 532 nm and 1,550 nm. The refractive index of each sample was measured in the in-plane MD direction (Nx), in-plane TD direction (Ny), and thickness direction (Nz). The root mean square of Nx, Ny, and Nz was taken as the refractive index of each sample. Since it is difficult to measure the refractive index of the uneven layer 12 having the convex portions 14, a flat sample without the convex portions 14 was separately prepared using the same resin composition as the uneven layer 12, and the refractive index of this sample was measured.

[0120] <Production of a Disc-Shaped Mold> An aluminum ingot with a purity of 99.99% was cut into a disc with a diameter of 65 mm and a thickness of 3 mm. The disc surface was polished to prepare a disc plate of an aluminum substrate without rolling marks. The disc surface of the disc plate was anodized in a 0.3% by mass oxalic acid aqueous solution at a DC voltage of 40 V or 80 V and a temperature of 16°C (anodizing treatment step). The disc plate with an oxide film formed on the disc surface was immersed in a 4.90% by mass phosphoric acid aqueous solution at 32°C to perform a pore size expansion treatment (pore size expansion treatment step). By repeating this anodizing treatment step and pore size expansion treatment step, a disc-shaped mold with anodized alumina formed on the surface was obtained. By appropriately adjusting the time and number of anodizing treatments and pore size expansion treatments, molds 1, 2, 4, 5, and 6 were obtained, each with different average pore spacing and depth. Each mold was immersed in a 0.1% by mass diluted aqueous solution of a (poly)oxyalkylene alkyl phosphate compound, air-dried overnight, and the surface of the mold was treated with a mold release agent.

[0121] <Production of Roll-Shaped Mold> A 99.99% pure aluminum ingot was cut to an outer diameter of 200 mm, an inner diameter of 155 mm, and a length of 350 mm to prepare a cylindrical aluminum substrate without rolling marks. The outer surface of the aluminum substrate was anodized in a 0.4% by mass oxalic acid aqueous solution at a DC voltage of 80 V and a temperature of 16°C (anodizing treatment step). The aluminum substrate with an oxide coating formed on the outer surface was immersed in a 5.0% by mass phosphoric acid aqueous solution at 32°C to perform a pore size expansion treatment (pore size expansion treatment step). By repeating this anodizing treatment step and pore size expansion treatment step, a roll-shaped mold with anodized alumina formed on the outer surface was obtained. The anodizing treatment and pore size expansion treatment were repeated five times with the time appropriately adjusted to obtain Mold 3 and Mold 7, each with different average pore spacing and depth. Furthermore, the number of anodizing treatments and pore size expansion treatments was increased to 8, and the total time for the anodizing treatments and pore size expansion treatments was set to the same as for mold 3, thereby obtaining mold 8. The number of anodizing treatments and pore size expansion treatments was increased to 8, and the time for the anodizing treatments and pore size expansion treatments was appropriately adjusted, thereby obtaining mold 9. Each mold was immersed in a 0.1 mass% diluted aqueous solution of a (poly)oxyalkylene alkyl phosphate compound, air-dried overnight, and the surface of the mold was treated with a mold release agent.

[0122] <Preparation of Active Energy Ray-Curable Composition> 25 parts by mass of dipentaerythritol hexaacrylate, 25 parts by mass of pentaerythritol triacrylate, 25 parts by mass of polyethylene glycol diacrylate, 25 parts by mass of an ethylene oxide-modified compound of dipentaerythritol hexaacrylate, and 0.1 parts by mass of a (poly)oxyalkylene alkyl phosphate compound were mixed, and then 1 part by mass of a first photopolymerization initiator (trade name "Omnirad 184", manufactured by BASF) and 0.5 parts by mass of a second photopolymerization initiator (trade name "Omnirad 819", manufactured by BASF) were added and mixed to prepare active energy ray-curable composition 1. The refractive index at 1,550 nm of active energy ray-curable composition 1, which was irradiated with ultraviolet light to form a flat sample, was 1.50.

[0123] 25 parts by mass of dipentaerythritol hexaacrylate, 55 parts by mass of pentaerythritol triacrylate, 20 parts by mass of polyethylene glycol diacrylate, and 0.1 parts by mass of a (poly)oxyalkylene alkyl phosphate compound were mixed, and then 1 part by mass of a first photopolymerization initiator (trade name "Omnirad 184", manufactured by BASF Corporation) and 0.5 parts by mass of a second photopolymerization initiator (trade name "Omnirad 819", manufactured by BASF Corporation) were added and mixed to prepare active energy ray-curable composition 2.

[0124] Active energy ray-curable composition 3 was prepared by adding 1 part by mass of a first photopolymerization initiator (trade name "Omnirad 184", manufactured by BASF) and 0.5 parts by mass of a second photopolymerization initiator (trade name "Omnirad 819", manufactured by BASF) to 100 parts by mass of an ethylene oxide-modified compound of dipentaerythritol hexaacrylate and 0.1 parts by mass of a (poly)oxyalkylene alkyl phosphate compound and mixing them.

[0125] Example 1 A disk-shaped mold 1 and a superbirefringent polyethylene terephthalate film (trade name "Cosmoshine SRF" manufactured by Toyobo Co., Ltd., thickness 80 μm, refractive index at 1,550 nm 1.58) serving as a transparent substrate were superimposed. An active energy ray-curable composition 1 was supplied between the mold 1 and the transparent substrate. The active energy ray-curable composition 1 was then cured by irradiating ultraviolet light from the transparent substrate side. The cured product was peeled from the mold 1 to obtain an antireflection film having a fine uneven structure (moth-eye structure). When the surface of the obtained antireflection film having a fine uneven structure was observed with a scanning electron microscope, it was found that convex portions with a height of 340 nm and an interval P between convex portions of 150 nm were formed, and the reflectance at 900 nm at an incident angle of 70° was 7.6%.

[0126] Examples 2, 4, 5, and 6 and Comparative Examples 1, 2, and 4 Antireflection films were produced in the same manner as in Example 1, except that the disk-shaped mold and the active energy ray-curable composition were changed as shown in Table 1. In Comparative Example 2, coalescence of the convex portions occurred due to the narrow interval P between the convex portions.

[0127] Example 3 A roll-shaped mold 3 was rotated, and a superbirefringent polyester film (trade name "Cosmoshine SRF", manufactured by Toyobo Co., Ltd., thickness 80 μm) serving as a transparent substrate was run along the outer peripheral surface of the mold 3 in the direction of rotation of the mold 3, while an active energy ray-curable composition 1 was supplied between the outer peripheral surface of the mold 3 and the running transparent substrate. The active energy ray-curable composition 1 was cured by irradiating it with ultraviolet rays from the transparent substrate side. The cured product was peeled off from the mold 3, and an antireflection film having a fine uneven structure (moth-eye structure) was produced.

[0128] Example 7 An antireflection film was produced in the same manner as in Example 3, except that the transparent substrate was changed to a triacetyl cellulose film (trade name "KC4UAW" manufactured by Konica Minolta, Inc., thickness 40 μm, refractive index at 532 nm 1.48, refractive index at 1,550 nm 1.47).

[0129] Examples 8 and 9 Antireflection films were produced in the same manner as in Example 7, except that the roll-shaped mold was changed as shown in Table 1.

[0130] Comparative Example 3 An anti-reflection film was produced in the same manner as in Example 3, except that the roll-shaped mold was changed as shown in Table 1.

[0131] The measurement results of the spacing P between convex portions, the height H of the convex portions, TW / BW, elastic modulus, 900 nm reflectance, 1300 nm reflectance, 1550 nm reflectance, and water contact angle in the fine uneven structures of Examples 1 to 9 and Comparative Examples 1 to 4 are shown in Table 1.

[0132] The reflectance of light at an incident angle of 5° in Examples 1, 2, and 4 and Comparative Examples 1 and 2 is shown in Figure 3. The reflectance of light at an incident angle of 30° in Examples 1, 2, and 4 and Comparative Examples 1 and 2 is shown in Figure 4. The reflectance of light at an incident angle of 50° in Examples 1, 2, and 4 and Comparative Examples 1 and 2 is shown in Figure 5. The reflectance of light at an incident angle of 70° in Examples 1, 2, and 4 and Comparative Examples 1 and 2 is shown in Figure 6.

[0133] The reflectance of light at an incident angle of 5° in Examples 1, 4, 5, 6 and Comparative Example 4 is shown in Figure 7. The reflectance of light at an incident angle of 30° in Examples 1, 4, 5, 6 and Comparative Example 4 is shown in Figure 8. The reflectance of light at an incident angle of 50° in Examples 1, 4, 5, 6 and Comparative Example 4 is shown in Figure 9. The reflectance of light at an incident angle of 70° in Examples 1, 4, 5, 6 and Comparative Example 4 is shown in Figure 10.

[0134] The reflectance of light at an incident angle of 5° in Examples 3, 7, 8, 9 and Comparative Example 3 is shown in Figure 11. The reflectance of light at an incident angle of 30° in Examples 3, 7, 8, 9 and Comparative Example 3 is shown in Figure 12. The reflectance of light at an incident angle of 50° in Examples 3, 7, 8, 9 and Comparative Example 3 is shown in Figure 13. The reflectance of light at an incident angle of 70° in Examples 3, 7, 8, 9 and Comparative Example 3 is shown in Figure 14.

[0135]

[0136] In Table 1, PET represents a polyethylene terephthalate film, and TAC represents a triacetyl cellulose film.

[0137] As shown in Table 1, the antireflection films having a fine uneven structure of Examples 1 to 9 had low reflectance at 900 nm at an incident angle of 70° and low reflectance at 1550 nm at an incident angle of 5°, and were excellent in low reflectivity for light in the near-infrared region at a wide incident angle.

[0138] In Example 3, the thickness of the uneven layer 12 was made uniform by using a roll mold, and amplitude occurred due to the relationship between the thickness and the refractive index.

[0139] In Example 7, the same roll-shaped mold 3 as in Example 3 was used, but since the difference in refractive index between the uneven layer 12 and the transparent substrate was small, the amplitude was reduced and the low reflectivity was also superior.

[0140] In Example 8, the number of anodizing treatments and hole diameter enlargement treatments was increased, resulting in smoother projection shapes and superior low reflectivity.

[0141] On the other hand, the antireflection film of Comparative Example 1 had a low height H of the convex portions, a reflectance at 900 nm at an incident angle of 70° of more than 10%, and a high reflectance at 1550 nm at an incident angle of 5°, and thus had poor low reflectivity.

[0142] In the antireflection film of Comparative Example 2, in which the spacing P between the convex portions was 100 nm and the height H of the convex portions was 400 nm, coalescence of the convex portions occurred. In addition, the reflectance at 900 nm at an incident angle of 70° and an incident angle of 5° was significantly higher than in Examples 1 to 9.

[0143] The antireflection film of Comparative Example 3 had the same height H of the convex portions as that of Comparative Example 1, and the spacing P between the convex portions was changed, but this had almost no effect on the reflectance, and like Comparative Example 1, the reflectance at 900 nm at an incident angle of 70° exceeded 10%, indicating poor low reflectivity.

[0144] According to the present invention, it is possible to obtain a laminated sheet, a cured sheet, and a circuit board material having low dielectric properties and excellent heat resistance, which have low dielectric properties and excellent conductor adhesion, a low coefficient of linear thermal expansion, and which stably exhibit low dielectric properties even when subjected to temperature and humidity changes due to the usage environment.

[0145] REFERENCE SIGNS LIST 1 transparent molded body 10 transparent substrate 12 uneven layer 14 convex portion 22 mold 34 aluminum substrate 36 pore 38 oxide film 40 pore generation point

Claims

1. A transparent molded article comprising: a transparent substrate; and a concave-convex layer formed on at least one surface of the transparent substrate and made of a cured product of a curable composition, wherein the concave-convex layer has a fine concave-convex structure on its surface, in which the spacing P between adjacent convex portions is 80 nm or more and 400 nm or less, the height H of the convex portions of the fine concave-convex structure is 320 nm or more, and the ratio of the height H of the convex portions to the spacing P between adjacent convex portions (height H / spacing P) is 2.0 to 3.

9.

2. The transparent molded article according to claim 1, wherein the surface of the uneven layer having the fine uneven structure has an average reflectance of 10% or less for light with a wavelength of 850 to 950 nm at an incident angle of 70°.

3. The transparent molded article according to claim 1, wherein the average reflectance of the surface of the uneven layer having the fine uneven structure for light with a wavelength of 850 to 950 nm at an incident angle of 5° is 0.5% or less.

4. A transparent molded article according to claim 1, wherein the surface of the uneven layer having the fine uneven structure has an average reflectance of 1.0% or less for light with a wavelength of 1500 to 1600 nm at an incident angle of 5°.

5. The transparent molded article according to claim 1, wherein the modulus of elasticity of the convex portions of the fine concave-convex structure is 500 MPa or more and 3,000 MPa or less.

6. The transparent molded article according to claim 1, wherein the water contact angle of the convex portions of the fine concave-convex structure is 25° or less.

7. An optical member comprising the transparent molded article according to any one of claims 1 to 6.

8. A near-infrared sensor cover comprising the transparent molded article according to any one of claims 1 to 6.

9. The near-infrared sensor cover according to claim 8, which is flat.

10. The near-infrared sensor cover according to claim 8, which has a curved shape with a bending radius of 200 mm or more.

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