Wire grid polarizing element, method for manufacturing a wire grid polarizing element, projection display device and vehicle

Abstract

A wire grid polarizing element (1) comprises a substrate (10) made of an inorganic material, a base portion (21) made of an organic material and formed on the substrate (10), a grid structure (20) having a plurality of convex portions (22) integrally formed, and a functional film (30) made of a metal material and covering a portion of the convex portions (22). The organic material is a cured product of a photocurable acrylic resin for imprinting containing a photopolymerization component, the photopolymerization component comprises resin (A) and resin (B), resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and resin (B) is a difunctional compound, wherein the content of resin (A) relative to the total photopolymerization component is 20 mass% or more and 42 mass% or less, and the content of resin (B) relative to the total photopolymerization component is 43 mass% or more and 66 mass% or less.

Description

Technology Field

[0001] The present invention relates to a wire grid polarizing element having good polarization characteristics, not causing deterioration in heat dissipation or manufacturing costs, and having excellent transmittance for incident light from oblique lines and incident light of a wide angle of incidence, a method for manufacturing a wire grid polarizing element, a projection display device having excellent polarization characteristics and heat resistance, and a vehicle equipped with said projection display device.

[0002] This application claims the benefit of priority based on Japanese Patent Application No. 2023-216487 filed on December 22, 2023 and Japanese Patent Application No. 2024-225993 filed on December 23, 2024, the contents of which are incorporated into this application. Background Technology

[0003] Recently, as a type of projection display device, many automotive head-up display devices have been developed that display images on a semi-transparent plate (hereinafter collectively referred to as the "display surface"), such as the front windshield or combiner of a vehicle. An automotive head-up display device is an image display device that is formed, for example, on the dashboard of a vehicle, projects image light onto the front windshield, and displays driving information as a virtual image. Since the driver can see the virtual image along with the scenery through the front windshield, there is an advantage that the driver's gaze is moved less compared to conventional display devices, such as liquid crystal displays, which are installed outside the range of the front windshield.

[0004] However, since the head-up display device described above emits a display image from below toward the front glass surface (upward), there were cases where sunlight entered in the opposite direction to the direction of the image emission and was incident on the display element. In head-up display devices, reflectors are often formed to reflect and enlarge the display image for the purpose of miniaturization or enlargement of the display image. In such cases, sunlight incident on the head-up display device is concentrated near the display element, and there was a risk that the display element would deteriorate or fail due to heat.

[0005] For this reason, a technology for forming a reflective polarizing element in a head-up display device is being developed for the purpose of preventing sunlight from being incident on the display element. For example, Patent Document 1 discloses a head-up display device in which a reflective polarizing element (wire grid polarizer) is formed between a reflector and a display element.

[0006] Here, polarizing elements formed in a head-up display device as described above may include, for example, a polarizing element made of a birefringent resin, a wire grid type polarizing element in which a plurality of conductors (metal wires) are extended parallelly on a transparent substrate, or a polarizing element made of a cholesteric liquid crystal. Among these, wire grid type polarizing elements with excellent polarization characteristics are widely used. In a wire grid type polarizing element, a wire grid is formed in which conductor wires composed of metal or the like are arranged in a grid pattern at a specific pitch. By making the arrangement pitch of the wire grid small (e.g., 1 / 2 or less) compared to the wavelength of the incident light (e.g., visible light), most of the light with an electric field vector component vibrating parallel to the conductor wires can be reflected, and most of the light with an electric field vector component perpendicular to the conductor wires can be transmitted. As a result, the wire grid type polarizing element can be used as a polarizing element that generates single polarization, and since it can reflect and reuse untransmitted light, it is also desirable from the perspective of effective light utilization. Furthermore, the polarizing element referred to herein includes a polarizing element capable of being used as a polarization beam splitter that separates incident light into S-polarization and P-polarization.

[0007] As such, a wire grid type polarizing element is disclosed in, for example, Patent Document 2, a wire grid polarizer comprising a resin substrate having a grid-like convex portion, a dielectric layer formed to cover the grid-like convex portion of the resin substrate, and a metal wire formed on the dielectric layer.

[0008] In addition, Patent Document 3 discloses a wire grid polarizer having a substrate made of resin or the like, having an uneven structure formed on its surface that extends in a specific direction, and a conductor formed to be located on one side of a convex portion of the uneven structure. In the wire grid polarizer, the pitch, which is the distance between two adjacent convex portions, and the height of the convex portion are adjusted when viewed in a cross-section perpendicular to the extension direction of the uneven structure.

[0009] In addition, Patent Document 4 discloses a projection-type image display device using a reflective liquid crystal display element and a reflective wire grid polarizer as a polarizing beam splitter. In the projection-type image display device using the reflective liquid crystal display element described in Patent Document 4, a reflective wire grid polarizer is positioned at an angle of approximately 45° with respect to the optical axis of the light emitted from a light source. The light emitted from the light source is separated into a first polarization (reflected light) and a second polarization (transmitted light) by entering the reflective wire grid at an angle of incidence of approximately 45° with respect to the reflective wire grid. Subsequently, the first polarization reflected from the reflective wire grid polarizer is modulated and reflected by the reflective liquid crystal display element to become the second polarization, and the second polarization passes through the reflective wire grid polarizer to be projected and displayed.

[0010] In addition, Patent Document 5 discloses a vehicle headlight using a reflective wire grid polarizer as a polarizing beam splitter. In the vehicle headlight described in Patent Document 5, the reflective wire grid polarizer is positioned at an angle of approximately 45° with respect to the optical axis of the light emitted from the light source. As the light emitted from the light source enters the reflective wire grid at an angle of incidence of approximately 45°, it is separated into a first polarized light (reflected light) and a second polarized light (transmitted light).

[0011] In the case where a reflective wire grid polarizer is positioned at an angle of approximately 45° with respect to light emitted from a light source, such as the projection type image display device described in Patent Document 4 and the vehicle headlight described in Patent Document 5, the incident light is not only incident at a single angle of incidence of 45° with respect to the reflective wire grid polarizer, but is also incident at an angle of incidence in the range of approximately 45° ± 15°.

[0012] In addition, Patent Document 6 discloses a wire grid polarizing beam splitter in which a plurality of grids, all made of silver or aluminum, are formed protrudingly on a substrate. Prior art literature

[0013] Japanese Published Patent Application No. 2018-72507 Japanese Published Patent Application No. 2008-83657 Japanese Published Patent Application No. 2017-173832 Japanese Published Patent Application No. 2004-184889 Japanese Published Patent Application No. 2019-50134 Japanese Published Patent Application No. 2003-508813 Japanese Published Patent Application No. 2018-125559 Japanese Patent Application No. 4824068 The problem to be solved

[0014] However, while the temperature environment generally required for devices used in vehicles is -40 to 105°C, high heat resistance and heat dissipation are required when considering use in high-temperature environments, such as head-up displays mounted on the dashboard inside the vehicle, especially during the summer. In this regard, there was a demand for additional improvement in terms of heat resistance and heat dissipation in the wire grid polarizers described in Patent Documents 1 to 3. Furthermore, in order to brightly illuminate the night road with the vehicle headlights described in Patent Document 5, high brightness of the vehicle headlights is essential. For this reason, the wire grid polarizers described in Patent Document 5 require high heat resistance and heat dissipation against heat from the light source.

[0015] In addition, conventional wire grid polarizing elements had the problem of increasing manufacturing costs or being unsuitable for mass production, as the surface irregularities were generally formed by photolithography or etching techniques.

[0016] The inventors, through repeated diligent research to solve the above-mentioned problem, have discovered the following findings. First, the substrate of the wire grid polarization element is formed from a transparent inorganic material, and the grid structure formed on the said substrate is integrally formed from a transparent organic material. As a result, the wire grid polarization element can be made into a hybrid structure composed of organic and inorganic materials. Consequently, the heat dissipation performance of the wire grid polarization element can be significantly improved.

[0017] In addition, as the grid structure, a grid structure is used in which a base portion formed along the surface of a substrate and a plurality of convex ridge portions protruding from the base portion are integrally formed. As such, since the grid structure can be formed by a technology such as nanoimprinting, the manufacturing cost of the grid structure can be reduced compared to cases where photolithography or etching technology is used, and mass production is also possible.

[0018] In addition, when forming a functional film, such as a light-reflecting film or a light-absorbing film, on the convex portion of the grid structure, the coverage range and coverage shape of the convex portion by said functional film are preferably adjusted. That is, the tip of the convex portion and the upper side of one or both sides are covered by the functional film, while the lower side of the side of the convex portion and the surface of the base portion are left open without being covered by the functional film. Furthermore, the functional film is formed in a rounded shape that bulges out in the width direction of the convex portion, so as to cover the tip of the convex portion and the upper side of the side. In addition, the maximum width (W) of the grid combined with the convex portion and the functional film covering said convex portion MAX) This, the width of the bottom of the convex part (W B The shape and size of the convex protrusion and the functional film are adjusted so as to be greater than ). In addition, it is preferable to limit the range in which the functional film covers the side of the convex protrusion to a specific range on the upper side of said side (for example, a range of 25% or more and 80% or less of the height (H) of the convex protrusion).

[0019] Thus, even when oblique incident light with a wide range of incident angles is incident on the wire grid polarizing element, the transmittance (Tp) of the second polarization (P polarization) in the wire grid polarizing element can be suppressed from decreasing depending on the incident angle. Therefore, the product (Tp × Rs) of the reflection axis reflectance (Rs) of the first polarization (S polarization) and the transmission axis transmittance (Tp) of the second polarization (P polarization) in the wire grid polarizing element can be maintained at a high value. Accordingly, when the wire grid polarizing element is used, for example, as a polarizing beam splitter, sufficient transmittance and polarization separation characteristics can be obtained even for oblique incident light with a large incident angle and a wide range.

[0020] However, in the imprint molding such as the nanoimprint described above, a fine irregular shape of a disc can be formed on a substrate by pressing the disc against an uncured resin layer formed on the substrate, curing the uncured resin layer in that state, and peeling off the disc.

[0021] In imprint molding, if the thickness of the uncured resin layer (layer thickness) is uneven when the disc is pressed against it, the peeling force applied when peeling the disc from the cured resin layer (hereinafter referred to as the "cured resin layer") becomes uneven within the surface of the cured resin layer. If this happens, there is a risk that a portion of the cured resin layer will peel off from the substrate. Furthermore, the cured resin layer that has peeled off from the substrate remains on the disc, making it impossible to reuse the disc. Additionally, when peeling the disc, the shape of the fine irregularities transferred to the cured resin layer may be deformed, and there is a risk that the optical properties resulting from the fine irregularity structure will deteriorate.

[0022] In addition, in imprint molding, if the uncured resin composition has low adherence to the fine irregular shape when a disc is pressed against it, a portion of the fine irregular shape of the disc is not transferred in the uncured resin layer.

[0023] Therefore, in order to make the thickness of the uncured resin layer uniform when a disc is pressed against it, and to improve the conformability of the uncured resin composition to the shape of fine irregularities, for example, in Patent Documents 7 and 8, a technique for lowering the viscosity of the uncured resin composition has been developed.

[0024] In order to lower the viscosity of the uncured resin composition, it is considered to increase the content of monofunctional monomers and low-viscosity difunctional monomers in the resin composition.

[0025] However, if the content of monofunctional monomers and low-viscosity difunctional monomers is increased, there is a problem that the heat resistance of the resin layer after curing is reduced.

[0026] Therefore, the present invention is made in consideration of these circumstances and aims to provide a wire grid polarizing element with excellent heat resistance, a method for manufacturing said polarizing element, and a projection display device and a vehicle equipped with said polarizing element. means of solving the problem

[0027] In order to solve the above problem, according to one aspect of the present invention,

[0028] A substrate made of inorganic material, and,

[0029] A grid structure made of an organic material, having a base portion formed on the substrate and a plurality of convex portions protruding from the base portion integrally formed thereon, and

[0030] It is made of a metal material and has a functional film that covers a portion of the convex portion, and

[0031] The above organic material is a cured product of a photocurable acrylic resin for imprinting containing a photopolymerization component, and

[0032] The above photopolymerization component is,

[0033] Suzy (A) and,

[0034] Includes resin (B),

[0035] The above resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and

[0036] The above resin (B) is a difunctional compound, and

[0037] The content of the resin (A) relative to the total photopolymerization component is 20 mass% or more and 42 mass% or less, and

[0038] A wire grid polarizing element is provided, wherein the content of the resin (B) relative to the entire photopolymerization component is 43 mass% or more and 66 mass% or less.

[0039] The above photopolymerization component further comprises a resin (C), and

[0040] The above resin (C) is an acrylate monomer having three or more functional groups, and

[0041] The content of the resin (C) relative to the entire photopolymerization component may be 1 mass% or more and 30 mass% or less.

[0042] The above resin (A) may be either or both of phenylethyl acrylate and benzyl acrylate.

[0043] The resin (B) may be one or more selected from the group consisting of (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene, and 1,6-hexanedioldiacrylate.

[0044] The above resin (B) may comprise one of 1,6-hexanediol diacrylate, (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, and bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene.

[0045] The above resin (C) may comprise one or both of dipentaerythritol hexaacrylate and tris-(2-acryloxyethyl)isocyanurate.

[0046] The viscosity of the above-mentioned photocurable acrylic resin for imprinting at 25 ℃ may be 90 mPa·s or less.

[0047] After maintaining the cured product of the above-mentioned photocurable acrylic resin for imprinting at 150°C for 500 hours,

[0048] The YI value of the cured product may be 3.0 or less.

[0049] At 30 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting is 2.0 × 10⁻⁶ 9 Pa or higher,

[0050] At 120 ℃, the storage modulus of the cured product is 1.3 × 10⁻⁶8 It may be considered as Pa or higher.

[0051] At 130 ℃, the storage modulus of the cured product is 1.4 × 10⁻⁶ 8 It may be considered as Pa or higher.

[0052] After maintaining the cured product of the above-mentioned photocurable acrylic resin for imprinting at 150°C for 500 hours,

[0053] The average transmittance of the said cured material for light in the wavelength range of 430 nm or more and 680 nm or less is 91% or more, and

[0054] The average transmittance of the cured material for light in the wavelength range of 430 nm or more and 510 nm or less may be 90% or more.

[0055] The above convex portion has a shape that tapers toward the end, with the width narrowing as it moves away from the base portion.

[0056] The above functional film covers the tip of the convex portion and the upper side of at least one side, and also does not cover the lower side of both sides of the convex portion and the base portion,

[0057] When the coverage rate (Rc) of the side of the convex portion by the functional film is the ratio of the height (Hx) of the portion covered by the functional film among the side of the convex portion to the height (H) of the convex portion, the coverage rate (Rc) may be 30% or more and 70% or less.

[0058] At least the portion of the above convex portion covered with the functional film may be inclined at an angle of inclination (α) greater than 0° and less than or equal to 15° with respect to the normal direction of the substrate.

[0059] The above convex portion is bent in the middle of the height direction of the above convex portion, and

[0060] The upper part of the above convex portion, above the above-mentioned curved position, may be inclined at the above-mentioned angle of inclination (α) with respect to the normal direction of the substrate.

[0061] The entire convex portion may be inclined at the angle of inclination (α) with respect to the normal direction of the substrate.

[0062] The above inclination angle (α) may be 5° or more and 10° or less.

[0063] The above functional film covers the tip and the upper sides of both sides of the convex portion, and

[0064] The coverage rate (Rc) of both sides of the convex portion by the above functional film may be 30% or more and 70% or less.

[0065] The coverage rate (Rc) of the first side of the inclined side of the convex part among the two sides of the convex part may be 35% or more and 50% or less.

[0066] The coverage rate (Rc) of the first side above may be 40% or more and 53% or less.

[0067] The coverage rate (Rc) of the second side opposite to the inclined side of the convex part among the two sides of the convex part may be 35% or more and 55% or less.

[0068] The coverage rate (Rc) of the second side above may be 35% or more and 45% or less.

[0069] The thickness (TB) of the above base portion may be 0.15 mm or less.

[0070] The thickness (TB) of the above base portion may be 0.09 mm or less.

[0071] The thickness (TB) of the above base portion may be 0.045 mm or less.

[0072] The thickness (TB) of the above base portion may be 0.02 mm or less.

[0073] A hybrid wire grid polarizing element may be formed by combining the substrate made of the above-mentioned inorganic material and the grid structure made of the above-mentioned organic material.

[0074] The surface of the functional film covering the convex portion has a rounded shape and bulges out in the width direction of the convex portion, and

[0075] The maximum width (W) of the functional film covering the above convex portion MAX ) is the width (W) of the convex part that is not covered by the functional film at a position 20% above the height of the convex part from the bottom of the convex part. B It is acceptable to make it more than )

[0076] The cross-sectional shape of the entire convex structure composed of the above-mentioned convex portion and the above-mentioned functional membrane may have a constriction with a narrowed width in the width direction of the entire convex structure located immediately below the lower portion of the above-mentioned functional membrane covering the above-mentioned convex portion.

[0077] The product (Tp × Rs) of the transmission axis transmittance (Tp) and the reflection axis reflectance (Rs) of incident light with an incident angle of 45° to the above wire grid polarizing element may be 70% or more.

[0078] The height (H) of the above convex portion may be 160 nm or more.

[0079] The thickness (Dt) of the functional film covering the tip of the convex portion may be 5 nm or more.

[0080] The thickness (Ds) of the functional film covering the side of the convex portion may be 10 nm or more and 30 nm or less.

[0081] The thickness (TB) of the above base portion may be 1 nm or more.

[0082] The cross-sectional shape of the convex portion in a cross-section orthogonal to the direction of the reflection axis of the wire grid polarizing element may be a trapezoid, triangle, curved shape, or ellipse that narrows in width as it moves away from the base portion.

[0083] At least a protective film formed to cover the surface of the above-mentioned functional film may be additionally provided.

[0084] The above protective film may include a water-repellent coating or an oil-repellent coating.

[0085] The above functional membrane may additionally have a dielectric membrane.

[0086] If θ is 30° or more and 60° or less,

[0087] The difference between the transmission axis transmittance (Tp(+)) of incident light with an incident angle of +θ and the transmission axis transmittance (Tp(-)) of incident light with an incident angle of -θ for the wire grid polarizing element above may be within 3%.

[0088] The above functional film may be a reflective film that reflects incident light.

[0089] The above wire grid polarizing element may be a polarizing beam splitter that separates incident oblique light into a first polarization and a second polarization.

[0090] In order to solve the above problem, according to another aspect of the present invention,

[0091] As a method for manufacturing the above-mentioned wire grid polarizing element,

[0092] A process of forming a grid structure material made of an organic material on a substrate made of an inorganic material, and

[0093] A process of forming a grid structure integrally formed with a base portion formed on the substrate and a plurality of convex portions protruding from the base portion by performing nanoimprinting on the grid structure material, and

[0094] The process includes forming a functional film that covers a portion of the convex portion using a metal material, and

[0095] The above organic material is a cured product of a photocurable acrylic resin for imprinting containing a photopolymerization component, and

[0096] The above photopolymerization component is,

[0097] Suzy (A) and,

[0098] Includes resin (B),

[0099] The above resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and

[0100] The above resin (B) is a difunctional compound, and

[0101] The content of the resin (A) relative to the total photopolymerization component is 20 mass% or more and 42 mass% or less, and

[0102] A method for manufacturing a wire grid polarizing element is provided, wherein the content of the resin (B) relative to the entire photopolymerization component is 43 mass% or more and 66 mass% or less.

[0103] The above-described photocurable acrylic resin for imprinting further comprises a photopolymerization initiator for polymerizing the above-described photopolymerization component, and

[0104] The process of forming the above grid structure is,

[0105] Mixing the above resin (A) and the above resin (B), and

[0106] It may also include mixing the photopolymerization initiator into the mixed resin of the above resin (A) and the above resin (B).

[0107] The above photopolymerization component further comprises a resin (C), and

[0108] The above resin (C) is an acrylate monomer having three or more functional groups, and

[0109] The content of the resin (C) relative to the total photopolymerization component is 1 mass% or more and 30 mass% or less, and

[0110] The process of forming the above grid structure is,

[0111] By mixing the above resin (A) and the above resin (B), a first mixed resin is produced, and

[0112] It may also include producing a second mixed resin by mixing the resin (C) with the first mixed resin.

[0113] In the process of forming the above functional film, film formation may be carried out alternately from multiple directions on the convex portion by sputtering or deposition.

[0114] In order to solve the above problem, according to another aspect of the present invention,

[0115] light source and,

[0116] A polarizing beam splitter positioned so that incident light from the light source is incident at an incident angle within a predetermined range including 45°, and which separates the incident light into a first polarization and a second polarization, and

[0117] A reflective liquid crystal display element arranged so that the first polarization reflected from the polarization beam splitter, or the second polarization transmitted through the polarization beam splitter, is incident, and reflects and modulates the incident first polarization or the second polarization;

[0118] A lens is provided such that the first polarization or the second polarization reflected and modulated from the reflective liquid crystal display element is incident through the polarization beam splitter, and

[0119] A projection display device is provided, wherein the above-described polarizing beam splitter is composed of the above-described wire grid polarizing element.

[0120] The incident angle of the above predetermined range may be 30° or more and 60° or less.

[0121] A heat dissipation member may be formed around the above-mentioned wire grid polarizing element.

[0122] In order to solve the above problem, according to another aspect of the present invention, a vehicle is provided that has the projection display device. Effects of the invention

[0123] According to the present invention, a wire grid polarizing element with excellent heat resistance can be provided. Brief explanation of the drawing

[0124] FIG. 1 is a cross-sectional view schematically showing a wire grid polarization element related to a first embodiment of the present invention. FIG. 2 is a plan view schematically showing a wire grid polarization element related to the same embodiment. FIG. 3 is a cross-sectional view schematically showing a specific example of a shape that tapers toward the end of a convex portion of a grid structure related to the same embodiment. FIG. 4 is a cross-sectional view schematically showing a specific example of the shape of a concave portion of a grid structure related to the same embodiment. FIG. 5 is a cross-sectional view schematically showing a wire grid polarization element related to the same embodiment. FIG. 6 is a cross-sectional view schematically showing a specific example of the shape of a reflective film related to the same embodiment. FIG. 7 is a cross-sectional view schematically showing a polarizing element covered with a protective film related to the same embodiment. FIG. 8 is a cross-sectional view schematically illustrating a modified example of a polarizing element covered with a protective film related to the same embodiment. FIG. 9 is a perspective view schematically showing a polarizing element equipped with a heat dissipation member related to the same embodiment. FIG. 10 is a photograph showing an actual grid structure and a reflective film related to the same embodiment. FIG. 11 is a process diagram showing a method for manufacturing a wire grid polarizing element related to the same embodiment. FIG. 12 is a process diagram showing a method for manufacturing a conventional wire grid polarizing element. FIG. 13 is a process diagram showing a method for manufacturing a disc related to the same embodiment. FIG. 14 is a schematic diagram showing a head-up display device, which is an example of a projection display device related to the same embodiment. FIG. 15 is a schematic diagram showing a first embodiment of a projection display device related to the same embodiment. FIG. 16 is a schematic diagram showing a second embodiment of a projection display device related to the same embodiment. FIG. 17 is a schematic diagram showing a third embodiment of a projection display device related to the same embodiment. FIG. 18 is a cross-sectional view schematically showing a wire grid polarization element related to a second embodiment of the present invention. FIG. 19 is a cross-sectional view schematically illustrating a modified example of a wire grid polarization element related to a second embodiment of the present invention. FIG. 20 is a drawing for explaining a polarizing element related to Example 40. FIG. 21 is a drawing for explaining a polarizing element related to Example 40. FIG. 22 is a drawing for explaining a polarizing element related to Example 42. FIG. 23 is a drawing for explaining a polarizing element related to Example 43. FIG. 24 is a diagram for explaining a polarizing element related to Example 44. Specific details for implementing the invention

[0125] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Furthermore, in this specification and drawings, components having substantially the same functional configuration are given the same reference numerals to avoid redundant descriptions. Additionally, for convenience of explanation, the state of each component disclosed in the following drawings may be schematically depicted with a scale and shape different from the actual one.

[0126] <1. Overview of Wire Grid Polarizing Devices>

[0127] First, with reference to FIG. 1 and FIG. 2, an overview of a wire grid polarization element (1) related to the first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view schematically showing a wire grid polarization element (1) related to the present embodiment. FIG. 2 is a plan view schematically showing a wire grid polarization element (1) related to the present embodiment.

[0128] The wire grid polarizing element (1) related to the present embodiment is a reflective polarizing element and also a wire grid type polarizing element. The wire grid polarizing element (1) may, for example, be a plate-shaped wire grid polarizing plate. The wire grid polarizing plate is a wire grid type polarizing plate having a plate shape. The wire grid polarizing plate may, for example, be a flat plate or a curved plate. In short, the surface (the surface where light is incident) of the wire grid polarizing element (1) may be a flat surface or a curved surface. Below, an example in which the wire grid polarizing element (1) related to the present embodiment is a flat wire grid polarizing plate is described, but the wire grid polarizing element of the present invention is not limited to this example and may have any shape depending on its use and function, etc.

[0129] In addition, the wire grid polarization element of the present invention may be used, for example, as a polarizer that transmits only light vibrating in a specific direction, or as a polarization beam splitter that separates incident light into a first polarization (S polarization) and a second polarization (P polarization). Below, examples in which the wire grid polarization element (1) related to the present embodiment is used as a polarization beam splitter will be mainly described.

[0130] As shown in FIGS. 1 and 2, a wire grid polarizing element (1) (hereinafter abbreviated as “polarizing element (1)”) comprises a transparent substrate (10), a transparent grid structure (20), and an opaque functional film (e.g., a reflective film (30)).

[0131] In addition, in this specification, "transparent" means that the transmittance of light of wavelength λ belonging to a usage band (e.g., a visible light band, an infrared light band, or a visible light and infrared light band, etc.) is high, and for example, means that the transmittance of said light is 70% or more. The wavelength band of visible light is, for example, 360 nm or more and 830 nm or less. The wavelength band of infrared light (infrared) is larger than the wavelength band of visible light, for example, 830 nm or more. From the perspective of a preferred wavelength range of visible light projected as a display image, the wavelength λ of the usage band in the polarizing element (1) related to this embodiment is, for example, 400 nm or more and 800 nm or less, and more preferably 420 nm or more and 680 nm or less. Since the polarizing element (1) related to this embodiment is formed of a material that is transparent to light in the usage band, it does not have an adverse effect on the polarization characteristics of the polarizing element (1) or the transmittance of light.

[0132] The substrate (10) is made of a transparent inorganic material such as glass. The substrate (10) is a flat substrate having a predetermined thickness (TS).

[0133] The grid structure (20) is made of a transparent organic material, for example, an organic resin material such as a UV-curable resin or a thermosetting resin with excellent heat resistance. The grid structure (20) has an uneven structure for realizing the polarization function of the polarizing element (1). Specifically, the grid structure (20) has a base portion (21) formed along the surface of the substrate (10) and a plurality of convex portions (22) protruding in a grid pattern from the base portion (21). The base portion (21) and the plurality of convex portions (22) of the grid structure (20) are integrally formed using the same organic material.

[0134] The base portion (21) is a thin film having a predetermined thickness (TB) and is laminated over the entire surface of the substrate (10) (XY plane shown in FIG. 1 and FIG. 2). The thickness (TB) of the base portion (21) is preferably substantially the same thickness over the entire surface of the substrate (10), but it does not have to be exactly the same thickness and may vary with a certain error relative to the reference thickness of TB. For example, TB may vary by ± 3 µm relative to the reference thickness of 6 µm. In this way, the thickness (TB) of the base portion (21) is determined by allowing for a molding error when molding the base portion (21) by imprinting, etc.

[0135] A plurality of convex jaws (22) are arranged on the base portion (21) at equal intervals in the X direction at a predetermined pitch (P). Additionally, the pitch (P) is the spacing between the formation of the plurality of convex jaws (22) arranged in the X direction of the polarizing element (1). The plurality of convex jaws (22) are arranged in a grid pattern so as to extend in the Y direction parallel to each other. A predetermined gap is formed between two convex jaws (22) that are adjacent to each other in the X direction. This gap serves as an entry path for incident light. Each convex jaw (22) is a wall-shaped convex portion formed to protrude in a thin, long direction (the Y direction shown in FIG. 1 and FIG. 2). The height (H) in the Z direction and the width (W) in the X direction of the plurality of convex jaws (22) T , W B The convex portion (22) is substantially identical to each other. The length direction (Y direction) of the convex portion (22) is the direction of the reflection axis of the polarizing element (1), and the width direction (X direction) of the convex portion (22) is the direction of the transmission axis of the polarizing element (1).

[0136] The functional film is a film for imparting a specific function to the grid structure (20) of the polarizing element (1). The functional film is, for example, made of an opaque metal material and is formed to cover a part of the convex portion (22) of the grid structure (20). The functional film may, for example, be a reflective film (30) having the function of reflecting incident light incident on the polarizing element (1), or an absorbing film (not shown) having the function of absorbing said incident light, or a film having other functions. In this embodiment, an example in which the functional film is a reflective film (30) is described, but the functional film of the present invention is not limited to the example of a reflective film (30).

[0137] The reflective film (30) is a thin film made of a metal material (metal or metal oxide, etc.), such as aluminum or silver, for example. The reflective film (30) is formed to cover at least the top of the convex portion (22). The reflective film (30) may be composed of a metal film that functions as a metal wire of the wire grid. The reflective film (30) has the function of reflecting incident light incident on the grid structure (20).

[0138] The convex portion (22) of the grid structure (20) and the reflective film (30) constitute the grid of the wire grid polarizing element (1). The pitch (P) in the X direction of the plurality of convex portions (22) in the grid structure (20) (i.e., the arrangement pitch of the grid) is set to a small pitch (e.g., 1 / 2 or less) compared to the wavelength λ of the incident light (e.g., visible light). Thus, the polarizing element (1) can mostly reflect light (S polarization) with an electric field vector component vibrating in a direction parallel to the reflective film (30) (conductive line) extending in the Y direction (reflection axis direction: Y direction), and mostly transmit light (P polarization) with an electric field vector component vibrating in a direction perpendicular to the reflective film (30) (conductive line) (transmission axis direction: X direction).

[0139] As described above, the wire grid polarizing element (1) related to the present embodiment realizes a polarizing function by combining a grid structure (20) having a fine uneven structure and a functional film (e.g., a reflective film (30)) that is selectively added to the convex portion (22) of the grid structure (20). Furthermore, the substrate (10) of the wire grid polarizing element (1) is made of an inorganic material such as glass with excellent heat resistance, and the grid structure (20) is made of an organic resin material with heat resistance. Thus, the wire grid polarizing element (1) related to the present embodiment is a hybrid type polarizing element that combines organic and inorganic materials. Therefore, since heat can be efficiently dissipated from the grid structure (20), which has a low thermal resistance R [㎡·K / W], to the substrate (10), it has excellent heat dissipation properties. Accordingly, the hybrid wire grid polarizing element (1) related to the present embodiment has excellent heat resistance and heat dissipation compared to a conventional film-type polarizing element (heat resistance: about 100°C) made only of organic materials, and has heat resistance in a high-temperature environment up to, for example, about 200°C. Therefore, it is possible to maintain a good heat dissipation effect while realizing excellent polarization characteristics.

[0140] Additionally, the wire grid polarizing element (1) related to the present embodiment may be provided with a protective film (40) (see FIG. 7 and FIG. 8) covering the surface of the grid structure (20). The protective film (40) is made of an inorganic material, for example, a dielectric material such as SiO2. The protective film (40) may be laminated over the entire surface of the wire grid polarizing element (1) to cover all surfaces of the base portion (21), the convex portion (22), and the reflective film (30) of the grid structure (20) (see FIG. 7). By forming such a protective film (40), an advantageous effect is obtained in which the thermal resistance R of the polarizing element (1) can be further reduced, thereby enabling the realization of excellent polarization characteristics while maintaining a better heat dissipation effect.

[0141] In addition, as described above, the grid structure (20), in which the base portion (21) and the convex portion (22) are integrally formed, can be manufactured using printing technology such as nanoimprinting, so a fine uneven structure can be realized with a simple manufacturing process. Therefore, compared to manufacturing using photolithography technology or etching technology, the cost and effort required to manufacture the grid structure (20) can be reduced. Accordingly, the hybrid type polarizing element (1) related to this embodiment has the advantage of being able to significantly reduce manufacturing costs and lower the product unit price of the wire grid polarizing element (1) compared to a polarizing element made only of conventional inorganic materials.

[0142] Meanwhile, conventional film-type organic polarizers use a large amount of organic material, and the thickness of the substrate (base film), double-sided tape (OCA: Optically Clear Adhesive), and grid structure is large, so compared to the hybrid type polarizing element (1) related to this embodiment, it is thought that the heat dissipation and heat resistance are inferior.

[0143] In addition, the wire grid polarizing element (1) related to the present embodiment has a grid composed of a convex portion (22) of a grid structure (20) and a reflective film (30), which has a special tree shape as shown in FIG. 1, etc. (details will be described later). Thus, even when light is incident from an oblique direction with a wide range of large incident angles θ (e.g., 30 to 60°) on the polarizing element (1), the transmittance of the second polarization (P polarization) (i.e., transmittance of the transmission axis Tp) passing through the polarizing element (1) can be suppressed from decreasing depending on the incident angle θ of the obliquely incident light. Accordingly, the product of the first polarization (S polarization) reflected from the wire grid polarization element (1) (i.e., reflection axis reflectance Rs) and the transmission axis transmittance Tp (Tp × Rs) can be maintained at a high value of, for example, 70% or more. Accordingly, the polarization element (1) related to the present embodiment has excellent polarization separation characteristics represented by Tp × Rs, and can polarize incident light and preferably separate it into S polarization (reflected light) and P polarization (transmitted light). Accordingly, the polarization element (1) related to the present embodiment can obtain sufficient transmittance and polarization separation characteristics even for incident light with a large incident angle θ and a wide range.

[0144] As described above, the wire grid polarization element (1) related to the present embodiment has excellent heat resistance and heat dissipation, and can reduce manufacturing costs. It also has excellent transmittance and polarization separation characteristics for oblique incident light with a wide range of large incident angles θ. Therefore, the wire grid polarization element (1) related to the present embodiment can be preferably applied as various parts of various products. For example, the polarization element (1) can be applied to a polarization beam splitter installed in a smart display, etc. Also, the polarization element (1) can be applied to a polarization element that counteracts heat from sunlight, a polarization element that counteracts heat from an LED light source, a polarization reflective mirror, etc., installed in a head-up display (HUD). Additionally, the polarization element (1) can be applied to a polarization beam splitter installed in a headlight such as a variable beam headlamp (ADB). In addition, the polarizing element (1) can also be applied to lens-integrated phase difference elements, lens-integrated polarizing elements, etc., installed in various devices for augmented reality (AR) or virtual reality (VR).

[0145] <2. Components of a Wire Grid Polarizing Device>

[0146] Next, with reference to FIG. 1 and FIG. 2, the components of the wire grid polarization element (1) related to the present embodiment will be described in detail.

[0147] <2.1. Substrate>

[0148] As shown in FIG. 1, the wire grid polarization element (1) related to the present embodiment comprises a transparent substrate (10). The substrate (10) is made of an inorganic material that is transparent and has a certain degree of strength.

[0149] As for the material of the substrate (10), it is preferable to use an inorganic material such as various types of glass, quartz, crystal, or sapphire, for example, in order to obtain better heat dissipation and heat resistance, and an inorganic material with a thermal conductivity of 1.0 W / m·K or higher is more preferable, and an inorganic material with a thermal conductivity of 8.0 W / m·K or higher is even more preferable.

[0150] In addition, the shape of the substrate (10) is not particularly limited and can be appropriately selected according to the performance required of the polarizing element (1). For example, it can be configured to have a plate-like shape or a curved surface. Also, from the perspective of not affecting the polarization characteristics of the polarizing element (1), the surface of the substrate (10) can be made flat. In addition, the thickness (TS) of the substrate (10) is not particularly limited and can be, for example, in the range of 0.02 to 10.0 mm.

[0151] <2.2. Grid Structure>

[0152] As shown in FIGS. 1 and 2, the polarizing element (1) related to the present embodiment has a grid structure (20) having the base portion (21) and the grid-shaped convex portion (22) on a substrate (10). The grid structure (20) can obtain desired polarization characteristics by forming a reflective film (30), which will be described later, on the convex portion (22).

[0153] When light is incident on the surface side where the grid structure (20) is formed with respect to the polarizing element (1), a portion of the incident light is reflected by the reflective film (30). Among the light incident on the reflective film (30), light having an electric field component in a direction orthogonal to the length direction of the convex jaw (22) (i.e., the extension direction of the convex jaw (22) = the reflection axis direction: Y direction) (i.e., the width direction of the convex jaw (22) = the transmission axis direction: X direction) transmits the polarizing element (1) with high transmittance. Meanwhile, among the light incident on the reflective film (30), light having an electric field component in a direction parallel to the length direction of the convex jaw (22) (i.e., the extension direction of the convex jaw (22) = the reflection axis direction: Y direction) is mostly reflected by the reflective film (30). Therefore, in this embodiment, a single polarization can be produced by providing a grid structure (20) partially covered by a reflective film (30). In addition, the same polarization effect is obtained for light incident from the back side of the substrate (10).

[0154] As shown in FIG. 1, the grid structure (20) has a base portion (21). The base portion (21) is a thin film formed along the surface of the substrate (10) and is a part for supporting the convex portion (22). When the uneven structure (convex portion (22)) of the grid structure (20) is formed by nanoimprinting or the like, the base portion (21) is inevitably formed. The base portion (21) and the convex portion (22) are integrally formed from the same material. Also, by having the base portion (21) of the grid structure (20), the strength of the convex portion (22) can be increased compared to the case where the convex portion (22) is formed directly on the substrate (10). Because of this, the durability of the grid structure (20) can be increased. In addition, since the base portion (21) is in close contact with the substrate (10) over the entire surface, the peel resistance of the grid structure (20) can be increased.

[0155] In addition, the thickness (TB) of the base portion (21) is not particularly limited, but from the perspective of more reliably supporting the convex portion (22) or facilitating imprint molding, it is preferable that it be 1 nm or more, and more preferable that it be 10 nm or more. Also, from the perspective of securing good heat dissipation, the thickness (TB) of the base portion (21) is preferably 50 μm or less, and more preferable that it be 30 μm or less.

[0156] In addition, according to the polarizing element (1) related to the present embodiment, since the base portion (21) of the grid structure (20) and a plurality of convex portions (22) are formed directly on the substrate (10), the thickness (TB) of the base portion (21) can be made thin. Here, in order to improve heat dissipation from the grid structure (20) to the substrate (10), it is desirable to reduce the temperature difference ΔT [°C] between the surface and the back side of the base portion (21) by making the thickness (TB) of the base portion (21) thin. In addition, the temperature difference ΔT is the temperature difference between the temperature T1 [°C] of the outermost surface of the base portion (21) (the source portion of the plurality of convex portions (22)) and the temperature T2 [°C] of the base portion (21) at the interface between the base portion (21) and the substrate (10) (ΔT = T1 - T2).

[0157] Accordingly, it is preferable that the thickness (TB) of the base portion (21) be 0.15 mm or less. By doing so, heat from the grid structure (20) made of organic material is rapidly transferred to the substrate (10) made of inorganic material and efficiently escapes from the substrate (10) to the outside of the polarizing element (1), thereby allowing heat dissipation, so that the temperature difference ΔT can be reduced to, for example, 32 ℃ or less. In addition, it is more preferable that the thickness (TB) of the base portion (21) be 0.09 mm or less, so that the temperature difference ΔT can be reduced to, for example, 20 ℃ or less. In addition, it is more preferable that the thickness (TB) of the base portion (21) be 0.045 mm or less, so that the temperature difference ΔT can be reduced to, for example, 10 ℃ or less. In addition, it is particularly preferable that the thickness (TB) of the base portion (21) be 0.02 mm or less, thereby allowing the temperature difference ΔT to be, for example, 5 ℃ or less. In this way, by making the thickness (TB) of the base portion (21) thin, the heat dissipation from the grid structure (20) to the outside through the substrate (10) can be improved, and thus the heat dissipation and heat resistance of the polarizing element (1) can be improved.

[0158] Additionally, the grid structure (20) has a plurality of convex jaws (22) protruding from the base portion (21), as shown in FIGS. 1 and 2. The convex jaws (22) are extended along the length direction in the direction of the reflection axis (Y direction) of the polarizing element (1) related to the present embodiment. A grid-like uneven structure is formed by arranging the plurality of convex jaws (22) at a predetermined pitch in the X direction and also arranging them at a predetermined distance from each other.

[0159] Here, as shown in FIG. 1, in the longitudinal section (XZ section) orthogonal to the reflection axis direction (Y direction) of the polarizing element (1), the pitch (P) of the convex wrench (22) in the transmission axis direction (X direction) needs to be shorter than the wavelength of the light in the usage band. This is to obtain the polarization effect described above. More specifically, the pitch (P) of the convex wrench (22) is preferably 50 to 300 nm, more preferably 100 to 200 nm, and particularly preferably 100 to 150 nm, from the perspective of compatibility between the ease of manufacturing of the convex wrench (22) and polarization characteristics.

[0160] Also, as shown in FIGS. 1 and 2, the width (W) of the bottom of the convex portion (22) in the longitudinal section (XZ section) B ) is not particularly limited, but from the perspective of compatibility between ease of manufacturing and polarization characteristics, it is preferable to be about 10 to 150 nm, and more preferable to be about 10 to 100 nm. Also, the width (W) of the top of the convex portion (22) T Although not particularly limited, from the perspective of compatibility between ease of manufacturing and polarization characteristics, it is preferable that the length is about 5 to 60 nm, and more preferable that it is about 10 to 30 nm.

[0161] Also, the width (W) of the bottom of the convex portion (22) B ) and the width of the government (W T) can be measured by observing with a scanning electron microscope or a transmission electron microscope. For example, using a scanning electron microscope or a transmission electron microscope, a cross-section (XZ cross-section) orthogonal to the absorption axis direction or the reflection axis direction of the polarizing element (1) is observed, and for any four points of convex portions (22), the width of the convex portion (22) is measured at a height position 20% above the height (H) of the convex portion (22) from the bottom of the convex portion (22), and the arithmetic mean value is the width (W) of the bottom of the convex portion (22). B ...can be done as ). Also, for any four points of the convex portion (22), the width of the convex portion (22) is measured at a height position 20% below the height (H) of the convex portion (22) from the tip (22a) of the convex portion (22), and the arithmetic mean value is the width (W) of the upper part of the convex portion (22). T It can be done with ).

[0162] Also, as shown in FIG. 1, the height (H) of the convex portion (22) in the cross-sectional section (XZ cross-section) is not particularly limited, but from the perspective of ease of manufacturing and compatibility of polarization characteristics, it is preferable that it be about 50 to 350 nm, and more preferable that it be about 100 to 300 nm. In addition, the height (H) of the convex portion (22) can be measured by observing with a scanning electron microscope or a transmission electron microscope. For example, a cross-section perpendicular to the absorption axis direction or reflection axis direction of a polarizing element (1) can be observed using a scanning electron microscope or a transmission electron microscope, and for any four points of convex portions (22), the height of the convex portion (22) at the center position in the width direction of the convex portion (22) can be measured, and the arithmetic mean value thereof can be taken as the height (H) of the convex portion (22).

[0163] The shape of the convex jaw (22) of the grid structure (20) is preferably a shape that tapers toward the end in order to obtain good polarization separation characteristics for obliquely incident oblique light. Here, a shape that tapers toward the end means that the width (W) (width in the X direction in the XZ cross-section) of the convex jaw (22) gradually narrows as it moves away from the base portion (21), or in other words, a shape in which the width (W) of the convex jaw (22) gradually narrows as it moves from the bottom to the top of the convex jaw (22). Therefore, when the convex jaw (22) has a shape that tapers toward the end, the width (W) of the top of the convex jaw (22) T ) is the width (W) of the bottom of the convex portion (22). B becomes smaller than ) (W T < W B ).

[0164] FIG. 3 illustrates a specific example of a shape that tapers toward the end of a convex jaw (22) related to the present embodiment. As shown in FIG. 3, the cross-sectional shape of the convex jaw (22) in the longitudinal section (XZ section) may be various shapes such as a trapezoid, triangle, tapered shape, ellipse, or rounded wedge shape, where the width (W) narrows as it moves away from the base part (21), provided that the shape tapers toward the end. For example, the cross-sectional shape of the convex jaw (22A) shown in FIG. 3 is a trapezoid (tapered shape), the cross-sectional shape of the convex jaw (22B) is a triangle, the cross-sectional shape of the convex jaw (22C) is tapered, and the cross-sectional shape of the convex jaw (22D) is a wedge shape with rounded top and bottom. In this way, by having a shape in which the convex portion (22) tapers toward the end, it is easy to form a reflective film (30) covering part of the tip (22a) and side (22b) of the convex portion (22), and polarization characteristics can be imparted to the polarizing element (1). Additionally, since the shape in which it tapers toward the end can be formed by nanoimprinting, it is advantageous in terms of ease of manufacturing.

[0165] In addition, as the convex jaw (22) has a shape that tapers toward the end, such as a tapered shape, the refractive index of the grid structure (20) changes gradually. Therefore, just like a moth-eye structure, an effect of preventing reflection of incident light is obtained due to the change in the physical refractive index of the grid structure (20). Thus, the effect of reducing the reflectivity on the surface of the convex jaw (22) of the grid structure (20) and improving the transmittance of the grid structure (20) can also be expected.

[0166] Also, FIG. 4 shows a specific example of the shape of a concave portion (24) formed between adjacent convex portions (22, 22). The concave portion (24) is a groove extending in the longitudinal direction (Y direction) of the convex portion (22). As shown in FIG. 4, the cross-sectional shape of the concave portion (24) in the longitudinal section (XZ section) may be various shapes, provided that the width narrows toward the bottom of the concave portion (24). For example, the cross-sectional shape of the concave portion (24A) shown in FIG. 4 is a trapezoid (tapered shape), the cross-sectional shape of the concave portion (24B) is a triangle (V-shape), the cross-sectional shape of the concave portion (24C) is a roughly rectangular shape with a flat bottom, and the cross-sectional shape of the concave portion (24D) is a U-shape with a rounded bottom. For the shape of these concave portions (24), an optimal shape can be appropriately selected by considering productivity such as mold release when forming nanoimprints.

[0167] In addition, the material constituting the grid structure (20) is not particularly limited as long as it is a transparent organic material, and known organic materials may be used. For example, it is preferable to use various thermosetting resins, various UV-curing resins, etc. as the material for the grid structure (20) in order to ensure transparency and excellent ease of manufacturing.

[0168] In addition, regarding ease of manufacturing or manufacturing cost, it is preferable to use a material different from that of the substrate (10) for the material constituting the grid structure (20). Furthermore, if the materials of the grid structure (20) and the substrate (10) are different, the refractive indices of the two will be different. Because of this, if there is an effect on the refractive index of the entire polarizing element (1), a refractive index adjustment layer may be appropriately formed between the grid structure (20) and the substrate (10).

[0169] For example, as a material constituting the grid structure (20), a curable resin such as an epoxy polymerizable compound or an acrylic polymerizable compound may be used. An epoxy polymerizable compound is a monomer, oligomer, or prepolymer having one or more epoxy groups in a molecule. Examples of epoxy polymerizable compounds include various bisphenol-type epoxy resins (bisphenol A type, F type, etc.), novolak-type epoxy resins, various modified epoxy resins such as rubber and urethane, naphthalene-type epoxy resins, biphenyl-type epoxy resins, phenol novolak-type epoxy resins, stilbene-type epoxy resins, triphenolmethane-type epoxy resins, dicyclopentadiene-type epoxy resins, triphenylmethane-type epoxy resins, and prepolymers of these.

[0170] Acrylic polymerizable compounds are monomers, oligomers, or prepolymers having one or more acrylic groups in their molecules. Here, monomers are further classified into monofunctional monomers having one acrylic group in their molecules, difunctional monomers having two acrylic groups in their molecules, and polyfunctional monomers having three or more acrylic groups in their molecules.

[0171] "Monofunctional monomers" include, for example, carboxylic acids (acrylic acid, etc.), hydroxyl groups (2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate), alkyl or alicyclic monomers (isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, isobornyl acrylate, cyclohexyl acrylate), and other functional monomers (2-methoxyethyl acrylate, methoxyethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminopropyl acrylamide, Examples include N,N-dimethylacrylamide, acryloylmorpholine, N-isopropylacrylamide, N,N-diethylacrylamide, 2-(perfluorooctyl)ethylacrylate, 3-perfluorohexyl-2-hydroxypropylacrylate, 3-perfluorooctyl-2-hydroxypropylacrylate, 2-(perfluorodecyl)ethylacrylate, 2-(perfluoro-3-methylbutyl)ethylacrylate), 2,4,6-tribromophenolacrylate, 2,4,6-tribromophenol methacrylate, 2-(2,4,6-tribromophenoxy)ethylacrylate), 2-ethylhexylacrylate, etc.

[0172] Examples of “difunctional monomers” include tri(propylene glycol)diacrylate, trimethylolpropane-diallyl ether, urethane diacrylate, etc.

[0173] Examples of “polyfunctional monomers” include trimethylolpropane triacrylate, dipentaerythritol penta and hexaacrylate, ditrimethylolpropane tetraacrylate, etc.

[0174] Examples of compounds other than the acrylic polymerizable compounds listed above include acrylmorpholine, glycerol acrylate, polyether-based acrylate, N-vinylformamide, N-vinylcaprolactam, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, polyethylene glycol acrylate, EO-modified trimethylolpropane triacrylate, EO-modified bisphenol A diacrylate, aliphatic urethane oligomers, polyester oligomers, etc.

[0175] In addition, the curing initiator for the curable resin described above may include, for example, a thermal curing initiator and a photocuring initiator. The curing initiator may be one that is cured by any energy beam other than heat or light (e.g., electron beam). If the curing initiator is a thermal curing initiator, the curable resin is a thermal curing resin, and if the curing initiator is a photocuring initiator, the curable resin is a photocuring resin.

[0176] Among these, it is preferable to use a UV curing initiator as the curing initiator. A UV curing initiator is a type of photocuring initiator. Examples of UV curing initiators include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexylphenylketone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one. Accordingly, it is preferable that the curable resin be a UV-curable resin. Furthermore, from the perspective of transparency, it is more preferable that the curable resin be a UV-curable acrylic resin.

[0177] Additionally, the method of forming the grid structure (20) is not particularly limited as long as it is a method capable of forming the base portion (21) and the convex portion (22) described above. For example, a method of forming an uneven surface by photolithography or imprinting, etc., may be used. Among these, it is preferable to form the base portion (21) and the convex portion (22) of the grid structure (20) by imprinting, in order to form an uneven surface pattern easily and quickly and to reliably form the base portion (21).

[0178] When forming the base portion (21) and the convex portion (22) of a grid structure (20) by nanoimprinting, for example, a material for forming the grid structure (20) (grid structure material) is applied on a substrate (10), and then a disc with irregularities is pressed against the grid structure material, and then irradiation with ultraviolet light or application of heat is performed to cure the grid structure material. In this way, a grid structure (20) having the base portion (21) and the convex portion (22) can be formed.

[0179] <2.3. Semi-membrane (Functional membrane)>

[0180] The polarizing element (1) related to the present embodiment has a reflective film (30) formed on a convex portion (22) of a grid structure (20), as shown in FIGS. 1 and 2.

[0181] As shown in FIG. 1, the reflective film (30) is formed to cover a portion of the leading edge (22a) and side (22b) of the convex portion (22) of the grid structure (20). Also, as shown in FIG. 1, the reflective film (30) is formed to extend along the longitudinal direction (Y direction) of the convex portion (22) of the grid structure (20). Thus, the reflective film (30) can reflect light having an electric field component in a direction parallel to the longitudinal direction of the convex portion (22) (reflection axis direction: Y direction) among the light incident on the polarizing element (1).

[0182] The material constituting the reflective film (30) is not particularly limited as long as it is a material that has reflectivity to light in the usage band. For example, metal materials such as metal elements such as Al, Ag, Cu, Mo, Cr, Ti, Ni, W, Fe, Si, Ge, Te, or alloys containing one or more of these elements may be used.

[0183] Additionally, the reflective film (30) may be a single layer made of the metal or a multilayer film made of multiple metal films. Also, if the reflective film (30) has a reflective function, it may include other layers such as a dielectric film as needed. The dielectric film is a thin film made of a dielectric. The material of the dielectric film may be a general material such as SiO2, Al2O3, MgF2, or TiO2. Also, it is preferable that the refractive index of the dielectric film be greater than 1.0 and 2.5 or less. Additionally, since the optical properties of the reflective film (30) are also affected by the surrounding refractive index, the polarization properties may be controlled by the material of the dielectric film.

[0184] <2.4. Special Shapes of Convex and Reflective Films>

[0185] Here, the specific shape of the convex portion (22) of the grid structure (20) and the reflective film (30) in the polarizing element (1) related to the present embodiment is described in detail.

[0186] In the polarizing element (1) related to the present embodiment, as shown in FIGS. 1 and 5, the reflective film (30) is formed to cover the upper side of the leading edge (22a) and at least one side (22b) of the convex portion (22) of the grid structure (20), and not to cover the lower side of both sides (22b) of the convex portion (22) and the base portion (21). In addition, in the example of FIGS. 1 and 5, the reflective film (30) covers the upper side of both sides (22b) of the convex portion (22), but may cover the upper side of only one side (22b) of the convex portion (22).

[0187] Here, the “state in which the reflective film (30) covers the upper side of the leading edge (22a) of the convex portion (22) of the grid structure (20) and at least one side (22b)” is a state in which, as shown in FIG. 1 and FIG. 5, both the “leading edge (22a) of the convex portion (22)” and the “upper side of the side (22b) connecting the leading edge (22a) of the convex portion (22) and the base portion (21)” are continuously covered by the reflective film (30), while the “lower side of the side (22b)” and the “base portion (21)” are not covered by the reflective film (30) and are exposed. In this state, the reflective film (30) does not cover the entire side (22b) of the convex portion (22) (all sides (22b) from the tip (22a) of the convex portion (22) to the base portion (21).

[0188] In addition, the surface of the reflective film (30) covering the tip (22a) of the convex portion (22) and the upper side (hereinafter referred to as the "top of the convex portion (22)") of at least one side (22b) has a rounded, curved shape (e.g., a vertically elongated, approximately elliptical shape) and is bulging out in the width direction (X direction) of the convex portion (22). As such, the surface of the reflective film (30) has a rounded, smooth curved shape and does not have angular corners or stepped portions. The maximum width (W) of the reflective film (30) covering the top of the convex portion (22) in this manner MAX ) is the width (W) of the bottom of the convex portion (22). B That is all. Also, W MAX ne, W B A larger one is desirable.

[0189] Here, the maximum width (W) of the reflective film (30) covering the convex portion (22) MAX ) is the maximum horizontal width among the horizontal widths of the outermost surfaces on both sides of the reflective film (30) in the width direction (X direction) of the convex portion (22). As shown in FIGS. 1 and 5, etc., the horizontal width (width in the X direction) of the outermost surfaces on both sides of the reflective film (30) covering the convex portion (22) varies depending on the height position (height in the Z direction) of the reflective film (30), and the maximum value among these horizontal widths is the maximum width (W MAX ) is. In other words, the maximum width (W MAX ) is the maximum value of the sum of the thickness (Ds × 2) on both sides of the reflective film (30) and the horizontal width (W) of the convex portion (22). For example, when light is incident on the grid structure (20) from the front direction (Z direction) (when the angle of incidence θ = 0°), W MAX This corresponds to the effective grid width of the reflective film (30).

[0190] Width of the bottom of the convex part (22) (WB ) is the horizontal width (width in the X direction) of the convex portion (22) at a height position (height in the Z direction) 20% above the height (H) of the convex portion (22) from the lowest part of the convex portion (22) (upper surface of the base portion (21)), as shown in FIGS. 1 and 3. In short, the width (W) of the bottom of the convex portion (22) B ) is the horizontal width of the convex section (22) at a height of 0.2 × H upward from the upper surface of the base section (21).

[0191] Also, the width of the government of the convex grandfather (22) (W T ) is the horizontal width (width in the X direction) of the convex portion (22) at a height position (height in the Z direction) 20% below the height (H) of the convex portion (22) from the tip (22a) of the convex portion (22), as shown in FIGS. 1 and 3. In short, the width (W) of the top of the convex portion (22) T ) is the horizontal width of the convex section (22) at a height of 0.8 × H upward from the upper surface of the base section (21) (i.e., a height of 0.2 × H downward from the tip (22a) of the convex section (22).

[0192] Additionally, in the following description, the convex structure formed by combining the convex portion (22) and the reflective film (30) is referred to as a "grid," and the height of the convex structure formed by combining the convex portion (22) and the reflective film (30) (i.e., the grid) is referred to as the "grid height." Also, the maximum width (W) of the reflective film (30) covering the convex portion (22) MAX ) "Grid maximum width (W MAX It is called )" and the width of the bottom of the convex part (22) (W B ) "Grid bottom width (W B It is also sometimes referred to as )". Also, the width of the top of the convex part (22) (WT ) to 「Convex grandfather government width (W T It is referred to as )” and the width of the central position in the height direction of the convex part (22) is sometimes referred to as the “central width of the convex part.”

[0193] Thus, in this embodiment, the width (W) of the bottom of the convex portion (22) B As ), the horizontal width of the convex part (22) at a height position 20% above the lowest part (bottom) of the convex part (22) is used, and the width (W) of the top of the convex part (22) T As such, the horizontal width of the convex part (22) at a height position 20% lower from the tip (22a) of the convex part (22) is used. This is because the width of the lowest part of the convex part (22) on the upper surface of the base part (21) and the width of the tip (22a) of the convex part (22) vary greatly depending on the manufacturing conditions of the grid structure (20), so it is difficult to measure these widths precisely.

[0194] As described above, in the grid structure (20) related to the present embodiment, a convex jaw (22) with a shape that tapers toward the end and a reflective film (30) that covers only the upper side of the tip (22a) and side (22b) of the convex jaw (22) are formed. And, the lower side of the side (22b) of the convex jaw (22) is not covered by the reflective film (30) and is open.

[0195] As a result, the cross-sectional shape of the convex portion (22) covered with the curved reflective film (30) (in short, the cross-sectional shape of the grid) has the following special cross-sectional shape. That is, as shown in FIGS. 1 and 5, etc., the horizontal width of the upper portion of the convex portion (22) where the reflective film (30) exists (e.g., the maximum grid width (W) MAX)) is large, and the horizontal width of the portion extending from the center to the bottom side of the exposed convex portion (22) that is not covered by the reflective film (30) (e.g., the width of the bottom of the exposed convex portion (22) (W)) B )) is made small. And, the cross-sectional shape of the entire convex structure (i.e., “grid”) composed of the convex portion (22) and the reflective film (30) is inwardly constricted at a position just below the lower end of the curved reflective film (30) and has a constricted portion with a narrowed width in the X direction. This special cross-sectional shape of the grid can be likened to the shape of a tree. Specifically, the part of the tree’s leaves that are spread out in a round shape corresponds to the part of the reflective film (30) that covers the top of the convex portion (22), the part of the tree’s trunk corresponds to the lower part of the convex portion (22) that is not covered by the reflective film (30), and the part of the ground where the tree grows corresponds to the base portion (21). Therefore, in the following description, the special cross-sectional shape of the grid composed of the convex portion (22) of the grid structure (20) and the reflective film (30) as described above is referred to as the "special tree shape."

[0196] The grid of the grid structure (20) of the polarizing element (1) related to this embodiment has a special tree shape as described above. Thus, for example, when incident light is incident on the polarizing element (1) from an oblique direction, the effective grid width (W A ) becomes smaller, and the gap width (W G ) increases. Here, the effective grid width (W A ) is the width of the reflective film (30) in a direction perpendicular to the incident oblique light. Gap width (W G ) is the gap between two adjacent grid reflective films (30, 30), and is the width of the gap in a direction perpendicular to oblique incident light. Effective grid width (W AThe larger ) is, the more easily incident light is reflected from the reflective film (30) and the more difficult it is to reach the transparent convex portion (22) or base portion (21). Therefore, the transmittance of incident light in the polarizing element (1) is reduced. Meanwhile, the gap width (W G The larger the value, the easier it is for incident light to pass between two adjacent reflective films (30, 30) and reach the transparent convex portion (22) or base portion (21). Therefore, the transmittance for incident light can be increased.

[0197] Therefore, since the grid of the polarizing element (1) related to the present embodiment has the special tree shape, the gap width (W) for obliquely incident oblique light G The gap between the ) is enlarged, and the incident light passes through the gap between the round reflective film (30, 30) and reaches the transparent grid structure (20), making it easy to transmit. Therefore, since the transmission axis transmittance Tp of the incident light is high, the transmittance and polarization separation characteristics (Tp × Rs characteristics) for the incident light are excellent. In addition, the reflection function of the incident light by the reflective film (30) and the transmission function of the incident light by the grid structure (20) can be realized in a good balance, and the polarization separation characteristics for the incident light can be further improved.

[0198] <2.5. Method for Forming a Reflective Film and Specific Examples>

[0199] Here, with reference to FIG. 5, a method for forming a reflective film (30) is described.

[0200] As a method for forming a reflective film (30) so that the reflective film (30) covers a portion of the leading edge (22a) and both sides (22b) of the convex portion (22) of the grid structure (20), it is preferable to form the reflective film (30) by alternately performing sputtering or deposition from an oblique direction (film incidence angle (φ)) with respect to the convex portion (22) of the grid structure (20), as shown in FIG. 5. By doing so, the reflective film (30) can be formed to cover the leading edge (22a) and the upper side of both sides (22b) of the convex portion (22). Additionally, the film incidence angle (φ) for forming the reflective film (30) by sputtering or deposition is not particularly limited, but, for example, can be about 5 to 70° with respect to the surface of the substrate (10).

[0201] In this way, in the present embodiment, after forming a grid structure (20) made of a transparent material, a reflective film (30) made of a metal material is formed by sputtering or deposition. This allows the film formation conditions, material, and film thickness of the reflective film (30) to be easily changed. In addition, it can be easily adapted even when the reflective film (30) is made of a multilayer film. Because of this, it is possible to design a film utilizing interference effects by combining metals, semiconductors, and dielectrics, and when forming a reflective film (30) by etching as in the conventional technology, there is no need to consider the composition of materials that can be etched. By doing so, it becomes easy to adjust the reflectance of polarized waves parallel to the grid structure (20) or to adjust the transmittance (transmittance amount) of polarized light in a direction perpendicular to the grid. Additionally, by forming a grid structure (20) and then forming a reflective film (30), there is no need for equipment such as a vacuum dry etching device, nor is there a need to provide safety devices such as gas or etching materials suitable for complex processes. Therefore, running costs such as equipment investment and maintenance can be reduced, and cost advantages can be obtained.

[0202] In addition, the thickness (Dt) of the reflective film (30) covering the leading edge (22a) of the convex portion (22) shown in FIG. 5, or the thickness (Ds) of the reflective film (30) covering the side (22b) of the convex portion (22), is not particularly limited and can be appropriately changed according to the shape of the convex portion (22) of the grid structure (20) or the performance required of the reflective film (30). For example, from the perspective of obtaining better reflection performance, it is preferable to make the thickness (Dt, Ds) of the reflective film (30) 2 to 200 nm, more preferable to make it 5 to 150 nm, even more preferable to make it 10 to 100 nm, and particularly preferable to make it 15 to 80 nm. Also, the thickness (Ds) of the reflective film (30) is the thickness of the thickest part of the reflective film (30) covering the side (22b) of the convex portion (22), as shown in FIG. 5.

[0203] Also, the shape of the reflective film (30) is not particularly limited as long as it is a shape capable of forming the special tree shape described above, and can be appropriately selected according to the conditions of the device for forming the reflective film (30) or the performance required for the reflective film (30).

[0204] FIG. 6 is a cross-sectional view schematically showing a specific example of the shape of the reflective film (30). As shown in FIG. 6, the reflective film (30) may have various shapes, provided that it is curved to wrap around the top of the convex portion (22) (the upper side of the tip (22a) and the side (22b)).

[0205] For example, the reflective film (30A) shown in FIG. 6 covers the tops of convex parts (22A, 22B, 22C) of various cross-sectional shapes in a rounded manner and has a roughly elliptical shape that is greatly bulged in the width direction of the convex part (22). Also, the reflective film (30B) has a curved shape that covers the tops of the roughly wedge-shaped convex part (22D). Also, the reflective film (30C) has a curved shape that covers the tops of the trapezoidal convex part (22A). The coverage rate (Rc) of one side (22b) of the convex part (22) and the coverage rate (Rc) of the other side (22b) by these reflective films (30B, 30C) are generally the same.

[0206] Additionally, the reflective film (30D) covers the top of the approximately wedge-shaped convex portion (22D), but is distributed on one side (22b) of the convex portion (22) (the left side (22b) shown in FIG. 6). Specifically, the reflective film (30D) covers a wide area of ​​the left side (22b) of the convex portion (22), and the coverage rate (Rc) is about 80%. On the other hand, the reflective film (30D) covers only a narrow area of ​​the upper side of the right side (22b), and the coverage rate (Rc) is about 25%. In this way, the coverage rate (Rc) by the reflective film (30D) may differ between one side (22b) and the other side (22b) of the convex portion (22).

[0207] <2.6. Desirable Range of Coverage Rate (Rc) of Convex Curves by Reflective Film>

[0208] Next, a preferred range of coverage rate (Rc) of the side (22b) of the convex portion (22) by the reflective film (30) related to the present embodiment will be described.

[0209] It is preferable that the coverage rate (Rc) be 25% or more and 80% or less. Here, the coverage rate (Rc) is the ratio of the height (Hx) of the portion covered by the reflective film (30) on the side (22b) of the convex portion (22) shown in FIGS. 1 and 5 to the height (H) of the convex portion (22). The coverage rate (Rc) is represented by the following equation (1).

[0210] Rc [%] = (Hx / H) × 100... (1)

[0211] H: Height of the convex portion (22) in the Z direction

[0212] Hx: Height in the Z direction of the portion covered by the reflective film (30) on the side (22b) of the convex portion (22).

[0213] Also, the opening ratio Rr is the ratio of the height (H - Hx) of the portion of the side (22b) of the convex portion (22) that is not covered by the reflective film (30) to the height (H) of the convex portion (22) shown in FIGS. 1 and 5. The opening ratio Rr is represented by the following equation (2).

[0214] Rr [%] = ((H - Hx) / H) × 100... (2)

[0215] Based on the above definition, Rr = 100 - Rc. Therefore, when the coverage rate (Rc) of the side (22b) of the convex portion (22) by the reflective film (30) is 25% or more and 80% or less, the opening rate Rr of the side (22b) of the convex portion (22) by the reflective film (30) is 20% or more and 75% or less.

[0216] As described above, in the polarizing element (1) related to the present embodiment, it is preferable that the coverage rate (Rc) of the side (22b) of the convex jaw portion (22) by the reflective film (30) is 25% or more and 80% or less (in other words, the open rate Rr is 20% or more and 75% or less). Specifically, in the present embodiment, the reflective film (30) is formed to cover the tip (22a) of the convex jaw portion (22) and the upper side of both side (22b), and to leave the lower side of both side (22b) open without covering. Furthermore, it is preferable that the coverage rate (Rc) is 25% or more and 80% or less, more preferable that it is 30% or more and 70% or less, and even more preferable that it is 40% or more and 50% or less.

[0217] With this configuration, the polarizing element (1) related to the present embodiment can exhibit sufficient transmittance even for obliquely incident light with a large incident angle θ (e.g., 45 to 60°). For example, when the obliquely incident light is separated into S polarized light (reflected light) and P polarized light (transmitted light) by the polarizing element (1), the transmittance Tp of the P polarized light (transmitted light) passing through the polarizing element (1) can be maintained at a high value regardless of the incident angle θ of the obliquely incident light. In addition, by setting the coverage rate (Rc) to 25% or more and 80% or less, the contrast (CR = Tp / Ts), which is the ratio of the transmission axis transmittance (Tp) to the reflection axis transmittance (Ts), can be maintained at a good level, and the reflection action by the reflective film (30) described above can be more reliably exerted without depending on the incident angle θ. Therefore, regardless of the incident angle θ of the obliquely incident light, high transmittance of the transmitted light can be secured and polarization separation characteristics can be improved.

[0218] In contrast, as a comparative example, when the reflective film (30) is formed to cover only the tip (22a) of the convex portion (22) of the grid structure (20), or when it is formed to cover the entire tip (22a) of the convex portion (22) and the side (22b) of one side, the deviation of the transmittance Tp increases depending on the incident angle θ of the incident light, and it is thought that sufficient transmittance cannot be obtained even for incident light with a large incident angle θ. Also, as a comparative example, when the reflective film (30) covers the entire tip (22a) of the convex portion (22) of the grid structure (20) and both sides (22b) (when the coverage rate (Rc) is 100%), transmittance decreases significantly as the incident angle θ of the incident light increases.

[0219] Therefore, in order to improve the transmittance of transmitted light or polarization separation characteristics without relying on the incident angle θ of the incident light, it is preferable to cover the tip (22a) of the convex portion (22) and a part of at least one side (22b) (the upper side of the side (22b)) by a reflective film (30), as in the polarizing element (1) related to the present embodiment.

[0220] In addition, regarding the Tp × Rs characteristics required as a polarizing beam splitter (PBS), in the polarizing element (1) related to the present embodiment, it is preferable that the coverage rate (Rc) of the side (22b) of the convex portion (22) by the reflective film (30) is 25% or more and 80% or less.

[0221] When the coverage rate (Rc) is less than 25%, the transmission axis transmittance Tp of the P-polarized light passing through the polarizing element (1) decreases, and a deviation in the transmittance Tp occurs depending on the incident angle θ, and a sufficiently high value of Tp × Rs is not obtained. For this reason, for obliquely incident light with a large incident angle θ, sufficient transmittance of the transmitted light and polarization separation characteristics represented by Tp × Rs cannot be obtained. On the other hand, when the coverage rate (Rc) exceeds 80%, just as when the entire tip (22a) and both sides (22b) of the convex part (22) of the grid structure (20) are covered, as the incident angle θ of the obliquely incident light increases (e.g., 45 to 60°), the transmission axis transmittance Tp decreases, and thus the deviation in the transmittance Tp becomes large depending on the incident angle θ.

[0222] Accordingly, it is preferable that the coverage rate (Rc) of the side (22b) of the convex portion (22) by the reflective film (30) be 25% or more and 80% or less. Thus, when light is incident on the polarizing element (1) from an oblique direction with an incident angle θ of, for example, 45°, the transmission axis transmittance Tp of the second polarization (P polarization) passing through the polarizing element (1) can be made 75% or more. As a result, Tp × Rs can be made 70% or more. Therefore, even when a wide range of incident light is incident at a large incident angle θ, the transmittance of the second polarization (P polarization) in the direction of the transmission axis of the polarization element (1) can be increased, thereby improving the polarization separation characteristics of the polarization element (1), and the incident light can be preferably separated into the first polarization (S polarization) and the second polarization (P polarization) by the polarization element (1).

[0223] From the same perspective, it is more preferable that the coverage ratio (Rc) be 30% or more and 70% or less (in other words, the opening ratio Rr is 30% or more and 70% or less). Thus, in the case of the above oblique incidence condition, a high transmittance Tp of 80% or more and a high Tp × Rs of 72% or more can be obtained. Also, it is more preferable that the coverage ratio (Rc) be 30% or more and 60% or less (in other words, the opening ratio Rr is 40% or more and 70% or less). Thus, in the case of the above oblique incidence condition, a high transmittance Tp of 83% or more and a high Tp × Rs of 75% or more can be obtained. In addition, it is more preferable that the coverage rate (Rc) be 40% or more and 50% or less (in other words, the opening rate Rr is 50% or more and 60% or less). Thus, in the case of the above oblique incidence conditions, a very high transmittance Tp of 85% or more and a very high Tp × Rs of 77% or more can be obtained.

[0224] In addition, regarding the reflection axis reflectance Rs, it is desirable that the coverage rate (Rc) be 20% or more. Thus, in the case of the above oblique incidence condition, a high reflectance Rs of 85% or more is obtained.

[0225] Also, regarding the contrast CR (CR = Tp / Ts) of the transmitted light, a sufficient contrast CR is obtained when the coverage rate (Rc) is 20% or more. The higher the coverage rate (Rc), the higher the contrast CR is obtained.

[0226] <2.7. Desirable Range of Tp × Rs>

[0227] Next, a preferred range of “Tp × Rs,” which is an indicator representing the polarization separation characteristics of the wire grid polarization element (1) related to the present embodiment, will be explained.

[0228] Tp × Rs [%] is the product of the transmission axis transmittance (Tp) and the reflection axis reflectance (Rs) expressed as a percentage. This Tp × Rs is an indicator representing the polarization separation characteristics of the wire grid polarization element (1).

[0229] Tp × Rs [%] = (Tp [%] / 100) × (Rs [%] / 100) × 100

[0230] Additionally, as described above, the transmission axis transmittance (Tp) is the transmittance of the second polarization (P polarization) having an electric field component parallel to the transmission axis (X direction) of the polarization element (1). The reflection axis reflectance (Rs) is the reflectance of the first polarization (S polarization) having an electric field component parallel to the reflection axis (Y direction) of the polarization element (1).

[0231] When the wire grid polarization element (1) related to the present embodiment is used as a polarization beam splitter to separate incident light into S polarization and P polarization (see FIG. 15 to FIG. 17), the polarization element (1) is positioned at a predetermined angle (e.g., 45°) with respect to the incident light from the light source. For example, when incident light from the light source is incident on the polarization element (1) at an incident angle θ of approximately 45°, the incident light is separated by the polarization element (1) into a first polarization (S polarization: reflected light) and a second polarization (P polarization: transmitted light). S polarization is light that has an electric field component in a direction parallel to the longitudinal direction of the convex jaw (22) of the grid structure (20) (the reflection axis direction shown in FIG. 2: Y direction) among the incident light. Meanwhile, P-polarization is light that has an electric field component in a direction parallel to the width direction (transmission axis direction shown in FIG. 2: X direction) of the convex portion (22) of the grid structure (20) among the incident light.

[0232] S-polarization in the direction of the reflection axis mainly becomes reflected light reflected by the reflective film (30) of the polarizing element (1). The reflectance [%] of the S-polarization at this time is the reflection axis reflectance (Rs). The reflection axis reflectance (Rs) represents the ratio of S-polarization reflected from the polarizing element (1) among the S-polarization incident on the polarizing element (1). Also, the reflection axis transmittance (Ts) represents the ratio of S-polarization transmitted through the polarizing element (1) among the S-polarization incident on the polarizing element (1).

[0233] Meanwhile, P-polarization in the direction of the transmission axis mainly becomes transmitted light that passes through the transparent grid structure (20) and substrate (10) of the polarization element (1). The transmittance [%] of the P-polarization at this time is the transmission axis transmittance (Tp). The transmission axis transmittance (Tp) represents the ratio of P-polarization that passes through the polarization element (1) among the P-polarization incident on the polarization element (1). In addition, the transmission axis reflectance (Rp) represents the ratio of P-polarization reflected from the polarization element (1) among the P-polarization incident on the polarization element (1).

[0234] Therefore, a higher transmission axis transmittance (Tp) means that P-polarized light in the direction of the transmission axis can be efficiently transmitted. Also, a higher reflection axis reflectance (Rs) means that S-polarized light in the direction of the reflection axis can be efficiently reflected. Therefore, a higher value of Tp × Rs, which is the product of Tp and Rs, indicates that both the transmittance of P-polarized light (transmitted light) and the reflectance of S-polarized light (reflected light) are high, and the polarization separation characteristics as a polarization beam splitter are excellent.

[0235] Here, the preferred range of the value of Tp × Rs related to the present embodiment is described. Consider a case where light of a predetermined range of wavelengths (e.g., 430 to 680 nm) is incident on a polarizing element (1) related to the present embodiment from an oblique direction at a predetermined incident angle θ (e.g., 45°), and separated into P-polarized light (transmitted light) and S-polarized light (reflected light). In the case of such oblique incident conditions, from the perspective of good polarization separation characteristics of the polarizing element (1), it is preferable that Tp × Rs be 70% or more.

[0236] If Tp × Rs is less than 70%, the light utilization efficiency in a display device to which a polarizing element is applied is poor, the brightness of the display image is insufficient, and visibility is poor. In contrast, if Tp × Rs is 70% or more, the light utilization efficiency in a display device to which a polarizing element (1) is applied is increased, sufficient brightness of the display image can be secured, and visibility can be improved.

[0237] In addition, it is more desirable that Tp × Rs be 72% or higher, even more desirable that it be 75% or higher, and particularly desirable that it be 80% or higher. By doing so, the light utilization efficiency and the brightness and visibility of the displayed image can be further improved as described above.

[0238] <2.8. Desirable Range of Height (H) of the Convex Part>

[0239] For the polarizing element (1) related to the present embodiment, when incident light is incident at a relatively large incident angle θ (e.g., 45°), the height (H) (see FIG. 1, FIG. 3, etc.) of the convex portion (22) of the grid structure (20) is preferably 160 nm or more, more preferably 180 nm or more, and particularly preferably 220 nm or more. By doing so, a high transmission axis transmittance Tp, excellent Tp × Rs characteristics, and a high contrast CR of the transmitted light are obtained.

[0240] Specifically, regarding transmittance, if the height (H) of the convex portion (22) is 160 nm or more, the transmittance Tp of the obliquely incident light transmission axis becomes 80% or more, and a high transmittance is obtained. Furthermore, if H is 180 nm or more, a Tp of 85% or more is obtained, which is more preferable. Additionally, if H is 220 nm or more, a Tp of 87% or more is obtained, which is particularly preferable.

[0241] Furthermore, regarding the Tp × Rs characteristics required for a polarizing beam splitter (PBS), if the height (H) of the convex portion (22) is 160 nm or more, an excellent Tp × Rs of 70% or more is obtained. Additionally, if H is 180 nm or more, a Tp × Rs of 75% or more is obtained, which is more preferable. Furthermore, if H is 220 nm or more, a Tp × Rs of 77% or more is obtained, which is particularly preferable.

[0242] Also, regarding the contrast CR (CR = Tp / Ts) of the transmitted light, the height (H) of the convex portion (22) should be 100 nm or more, and if H is 160 nm or more, an excellent contrast CR of 150 or more is obtained. Furthermore, if H is 180 nm or more, an excellent CR of 250 or more is obtained, so it is more preferable. Additionally, if H is 220 nm or more, an excellent CR of 500 or more is obtained, so it is particularly preferable.

[0243] As described above, in order to improve the various characteristics (Tp, Tp × Rs, CR) of the polarizing element (1), particularly Tp, it can be seen that the height (H) of the convex ridge (22) is preferably larger. The reason for this is thought to be as follows. That is, when the film incidence angle (φ) (see FIG. 5) when forming a reflective film (30) on the convex ridge (22) by sputtering or deposition, etc. is the same, the lower the height (H) of the convex ridge (22), the greater the coverage rate (Rc) by the reflective film (30). As the coverage rate (Rc) increases, the range of the convex ridge (22) covered by the reflective film (30) widens, so it becomes difficult for P-polarized light to pass through the grid structure (20), and the transmittance Tp decreases. Therefore, under the condition that the angle of incidence (φ) of the membrane is the same, it is desirable to increase the transmittance Tp by making the height (H) of the convex portion (22) larger, thereby reducing the coverage rate (Rc).

[0244] <2.9. Preferred Range of Lead Thickness (Dt) of Functional Film (Reflective Film)>

[0245] For the polarizing element (1) related to the present embodiment, when incident light is incident at a relatively large incident angle θ (e.g., 45°), the thickness (Dt) of the reflective film (30) covering the tip (22a) of the convex portion (22) of the grid structure (20) (tip thickness (Dt) of the reflective film (30): see FIG. 5) is preferably 5 nm or more, and more preferably 15 nm or more.

[0246] If the leading edge thickness (Dt) of the reflective film (30) is 5 nm or more, both the reflection axis reflectance Rs and the transmission axis transmittance Tp of the incident light are 85% or more, and a high transmittance is obtained. In addition, considering the Tp characteristic and the Tp × Rs characteristic required as a polarizing beam splitter, it is more preferable that Dt be 15 nm or more.

[0247] <2.10. Preferred range of lateral thickness (Ds) of functional film (reflective film)>

[0248] Additionally, the thickness (Ds) of the reflective film (30) covering the side (22b) of the convex portion (22) of the grid structure (20) (side thickness (Ds) of the reflective film (30): see FIG. 5) is preferably 10 nm or more and 30 nm or less, more preferably 12.5 nm or more and 25 nm or less, and particularly preferably 15 nm or more and 25 nm or less. By doing so, a high transmission axis transmittance Tp, excellent Tp × Rs characteristics, and a high contrast CR of the transmitted light are obtained.

[0249] Specifically, regarding transmittance, if the side thickness (Ds) of the reflective film (30) is 10 nm or more and 30 nm or less, the transmittance Tp of the obliquely incident light is 80% or more, and a high transmittance is obtained. In addition, if Ds is 12.5 nm or more and 25 nm or less, a Tp of 85% or more is obtained, so it is more preferable.

[0250] Also, regarding reflectivity, if the side thickness (Ds) of the reflective film (30) is 10 nm or more, the reflectivity of the reflection axis of the incident light Rs becomes 80% or more, and a high reflectivity is obtained. In addition, if Ds is 12.5 nm or more, Rs of 85% or more is obtained, so it is more preferable.

[0251] In addition, regarding the Tp × Rs characteristics required for a polarizing beam splitter (PBS), if the side thickness (Ds) of the reflective film (30) is 12.5 nm or more and 30 nm or less, an excellent Tp × Rs of 70% or more is obtained. Furthermore, if Ds is 15 nm or more and 25 nm or less, a Tp × Rs of 76% or more is obtained, which is more preferable.

[0252] Also, regarding the contrast CR (CR = Tp / Ts) of the transmitted light, the side thickness (Ds) of the reflective film (30) should be 10 nm or more, and if Ds is 12.5 nm or more, an excellent contrast CR of 50 or more is obtained. In addition, if Ds is 15 nm or more, a CR of 100 or more is obtained, so it is more preferable.

[0253] <2.11. Ubiquitous Distribution of Semi-deads>

[0254] In addition, in the polarizing element (1) related to the present embodiment, the reflective film (30) covering the convex jaw (22) may be distributed to one side of the convex jaw (22) to form a shape that is asymmetric to the left and right in the width direction (X direction) of the convex jaw (22). Specifically, the reflective film (30) may be distributed to one side (22b) of the convex jaw (22) by changing the side thickness (Ds) or coverage ratio (Rc) of the reflective film (30) between one side (22b) and the other side (22b) of the convex jaw (22). In short, the reflective film (30) may cover one side (22b) of the convex jaw (22) thickly and widely, and cover the other side (22b) thinly and narrowly.

[0255] In this way, when the reflective film (30) is distributed on one side of the convex jaw (22), it is preferable that the difference between the transmission axis transmittance Tp(+) of incident light with an incident angle of +θ (+30° to +60°) to the polarizing element (1) and the transmission axis transmittance Tp(-) of incident light with an incident angle of -θ (-30° to -60°) is within 3%. Furthermore, it is preferable to distribute the reflective film (30) appropriately on one side of the convex jaw (22) by adjusting the thickness (Ds) or coverage rate (Rc) of the reflective film (30) covering one side (22b) and the other side (22b) of the convex jaw (22), respectively, so that the difference between Tp(+) and Tp(-) is within 3%.

[0256] Additionally, an incident angle of +θ means that oblique incident light is incident from a direction inclined toward one side of the X direction (the width direction of the convex part (22)) with respect to the convex part (22). On the other hand, an incident angle of -θ means that oblique incident light is incident from a direction inclined toward the other side of the X direction with respect to the convex part (22).

[0257] As described above, when the reflective film (30) is placed on one side of the convex portion (22), it is desirable to keep the difference between Tp(+) and Tp(-) within 3%. Thus, even when the reflective film (30) is placed on one side of the convex portion (22), a high transmission axis transmittance Tp, excellent Tp × Rs characteristics, and a high contrast CR of the transmitted light are obtained.

[0258] Specifically, regarding transmittance, even if the reflective film (30) is distributed on one side, the transmittance of the oblique incident light with an incident angle θ of +45° and -45° is 85% or more, and a high transmittance is obtained.

[0259] Also, regarding reflectivity, even if the reflective film (30) is distributed on one side, the reflectivity of the reflective axis Rs of incident light with incident angles θ of +45° and -45° is 85% or more, and a high reflectivity is obtained.

[0260] Also, regarding the Tp × Rs characteristics required for a polarizing beam splitter (PBS), even if the reflective film (30) is localized to one side, the Tp × Rs of obliquely incident light with an incident angle θ of 45° becomes 75% or more, and excellent Tp × Rs characteristics are obtained.

[0261] Also, regarding the contrast CR (CR = Tp / Ts) of the transmitted light, an excellent contrast CR is obtained even when the reflective film (30) is distributed on one side. Furthermore, from the perspective of improving contrast, among the thicknesses (Ds) of the reflective film (30) covering one side (22b) and the other side (22b) of the convex portion (22), it is preferable that the thinner side thickness (Ds) is 5 nm or more (the coverage rate (Rc) is 22% or more), and it is more preferable that the thickness (Ds) of the thinner side reflective film (30) is 10 nm or more (the coverage rate (Rc) is 33% or more).

[0262] <2.12. Other Components>

[0263] The polarizing element (1) related to this embodiment may additionally include components other than the substrate (10), grid structure (20), and reflective film (30) described above.

[0264] For example, as shown in FIG. 7, it is preferable that the polarizing element (1) additionally has a protective film (40) formed to cover at least the surface of the reflective film (30). In detail, as shown in FIG. 7, it is more preferable that the protective film (40) covers the entire surface of the grid structure (20). That is, it is more preferable that the protective film (40) is formed to cover the entire surface of the side (22b) of the convex portion (22) of the grid structure (20), the surface of the base portion (21), and the surface of the reflective film (30). By forming such a protective film (40), the scratch resistance, antifouling, and water resistance of the polarizing element (1) can be further enhanced.

[0265] Additionally, it is more preferable that the protective film (40) further include a water-repellent coating or an oil-repellent coating. This allows the antifouling and waterproof properties of the polarizing element (1) to be further enhanced.

[0266] The material constituting the protective film (40) is not particularly limited as long as it can increase the scratch resistance, antifouling, and water resistance of the polarizing element (1). For example, the material constituting the protective film (40) may be a film made of dielectric material, and more specifically, may be an inorganic oxide, a silane-based water-repellent material, etc. Examples of inorganic oxides may be Si oxide, Hf oxide, etc. The silane-based water-repellent material may contain a fluorine-based silane compound such as perfluorodecyltriethoxysilane (FDTS), or may contain a non-fluorine-based silane compound such as octadecyltrichlorosilane (OTS).

[0267] Among these materials, it is more preferable to include at least one of an inorganic oxide and a fluorine-based water-repellent material. By including an inorganic oxide, the scratch resistance of the polarizing element can be further enhanced, and by including a fluorine-based water-repellent material, the antifouling and water resistance of the polarizing element can be further enhanced.

[0268] Additionally, the protective film (40) may be formed to cover at least the surface of the reflective film (30), but as shown in FIG. 7, it is more preferable that it be formed to cover the entire surface of the grid structure (20) and the reflective film (30). In this case, for example, as shown in the upper drawing of FIG. 7, the protective film (40) may cover the cross-section of the grid structure (20) (the cross-section of the base part (21)), or as shown in the lower drawing of FIG. 7, the protective film (40) may not cover the cross-section of the grid structure (20) (the cross-section of the base part (21)). Also, as shown in FIG. 8, the protective film (40) may be formed to cover the entire polarizing element (1), including the surface of the substrate (10) in addition to the surface of the grid structure (20) and the reflective film (30). In this way, by covering the outermost surface of the grid structure (20) or the polarizing element (1) with a protective film (40) made of an inorganic oxide, the thermal resistance R of the entire polarizing element (1) can be further reduced, so the heat dissipation of the polarizing element (1) is further improved.

[0269] In addition, the polarizing element (1) related to the present embodiment preferably has a heat dissipation member (50) formed to surround the substrate (10) as shown in FIG. 9. The heat transferred from the substrate (10) can be released more efficiently by this heat dissipation member (50). Here, the heat dissipation member (50) is not particularly limited as long as it is a member with a high heat dissipation effect. The heat dissipation member (50) may be, for example, a heat sink, a heat spreader, a die pad, a heat pipe, a metal cover, or a case body.

[0270] <2.13. Image of the actual grid structure>

[0271] Next, with reference to FIG. 10, an example is described in which a polarizing element (1) related to the present embodiment is actually manufactured and magnified using a scanning electron microscope (SEM). FIG. 10A is an SEM image of a grid structure (20) viewed from an oblique direction before being coated by a reflective film (30). FIG. 10B is an SEM image showing a cross-section of a convex jaw portion (22) of a grid structure (20) before being coated by a reflective film (30). FIG. 10C is an SEM image showing a cross-section of a convex jaw portion (22) of a grid structure (20) coated by a reflective film (30).

[0272] As shown in FIGS. 10A and 10B, the grid structure (20) has a base portion (21) formed along the surface of the substrate (10) and a convex portion (22) protruding from the base portion (21). A plurality of convex portions (22) are arranged at approximately equal pitches (P). Each convex portion (22) has a shape that tapers toward an end where the width narrows as it moves away from the base portion (21). The width (W) of the upper portion of the convex portion (22). T ) is the width (W) of the bottom of the convex portion (22). B It is narrower than ). The pitch (P) is the width (W) of the bottom of the convex portion (22). B It is sufficiently larger than ). The height (H) of the convex portion (22) is greater than the pitch (P). In the example of FIG. 10, P = 140 nm, W T = 10 nm, W B = 30 nm, H = 220 nm. Also, as shown in FIG. 10C, a reflective film (30) is formed to cover the tip (22a) and both sides (22b) of the convex portion (22). The outer surface of the reflective film (30) is curved in a rounded shape and bulges out in the width direction of the convex portion (22).

[0273] <3. Method for manufacturing a polarizing element>

[0274] Next, with reference to FIG. 11, a method for manufacturing a wire grid polarizing element (1) related to the present embodiment will be described. FIG. 11 is a process diagram showing a method for manufacturing a wire grid polarizing element (1) related to the present embodiment.

[0275] As described above, the polarization element (1) related to the present embodiment is a hybrid wire grid polarization element (1) composed of an inorganic material (substrate (10)) and an organic material (grid structure (20)). Below, a method for manufacturing the said hybrid wire grid polarization element (1) will be described.

[0276] As shown in FIG. 11, the method for manufacturing a wire grid polarizing element (1) related to the present embodiment includes a grid structure material forming process (S10), a nanoimprint process (S12), a grid structure forming process (S14), and a reflective film forming process (S16).

[0277] Grid structure material formation process (S10)

[0278] First, in S10, a grid structure material (23) made of a transparent organic material (e.g., UV-curable resin or thermosetting resin) is laminated onto a substrate (10) made of a transparent inorganic material (e.g., glass) by coating or the like. Additionally, the various materials described above may be used as the inorganic material of the substrate (10). Also, the various materials described above may be used as the organic material of the grid structure (20). Additionally, the film thickness of the grid structure material (23) can be appropriately adjusted according to the dimensions of the base portion (21) and the convex portion (22) of the grid structure (20) formed by the nanoimprint of S12.

[0279] Nanoimprint process (S12) and grid structure formation process (S14)

[0280] Next, in S12, a grid structure (20) is formed on a substrate (10) by performing a nanoimprint on the grid structure material (23). The grid structure (20) is a micro-irregular structure formed integrally with a base portion (21) formed on the substrate (10) and a plurality of convex portions (22) protruding from the base portion (21). The micro-irregular structure is, for example, a structure having fine convex and concave portions on the order of several nm to tens of nm.

[0281] In the nanoimprint process of S12, a disc (60) having an inverted shape of the micro-uneven shape of the grid structure (20) is used to transfer the micro-uneven shape of the disc (60) onto the surface of the grid structure material (23) (S12). As a result, an uneven pattern consisting of the base portion (21), the convex portion (22), and the concave portion (24) is formed on the grid structure material (23). Additionally, in the nanoimprint process, along with the transfer of the uneven pattern, an energy line is irradiated onto the grid structure material (23) to cure the grid structure material (23) with the transferred uneven pattern, thereby forming the grid structure (20) (S14). For example, if the grid structure material (23) is made of a UV-curable resin, the UV-curable resin with the transferred uneven pattern may be cured by irradiating the grid structure material (23) with UV light using a UV irradiation device (66). Alternatively, if the grid structure material (23) is made of a thermosetting resin, the thermosetting resin with the transferred uneven pattern may be cured by heating the grid structure material (23) using a heating device (68), such as a heater.

[0282] In the above processes S12 and S14, a convex portion (22) of the grid structure (20) is formed, having a shape that tapers toward the end and narrows in width as it moves away from the base portion (21). The convex portion (22) of the example in FIG. 11 is trapezoidal (tapered shape), but it may also have various other shapes that taper toward the end as shown in FIG. 3.

[0283] In this way, in the present embodiment, since a convex jaw portion (22) having a shape that tapers toward the end is imprinted in the nanoimprint process S12, the disc (60) can be easily peeled off from the grid structure material (23), and the mold removal capability is excellent. In addition, the convex jaw portion (22) of the grid structure (20) can be accurately molded into a desired shape without destroying the shape.

[0284] Reflective film formation process (S16)

[0285] Next, in S16, a reflective film (30) is formed by using a metal material such as Al or Ag to cover a portion of the convex portion (22) of the grid structure (20). The reflective film (30) is an example of a functional film that provides a specific function to the polarizing element (1). The reflective film (30) is a metal thin film (grid of metal wires) for reflecting incident light incident on the grid structure (20) of the polarizing element (1).

[0286] In this reflective film forming process S16, the reflective film (30) is formed as follows. That is, the reflective film (30) is formed so that it covers the leading edge (22a) of the convex portion (22) and the upper side of at least one side (22b), and does not cover the lower side of both sides (22b) of the convex portion (22) and the base portion (21). Additionally, the reflective film (30) is formed so that the surface of the reflective film (30) covering the convex portion (22) bulges roundly in the width direction of the convex portion (22). Furthermore, the maximum width (W) of the reflective film (30) covering the convex portion (22) MAX ) (Maximum grid width (W MAX )) This is the width of the bottom of the aforementioned convex part (W B ) (Grid bottom width (W B A reflective film (30) is formed so as to be greater than ))

[0287] As a method for forming such a reflective film (30), for example, sputtering or deposition methods can be used as shown in FIG. 5. A reflective film (30) is formed by sputtering or depositing a metal material alternately from an oblique direction with respect to the convex portion (22) of the grid structure (20). By doing so, a reflective film (30) of a desired shape can be preferably formed to roundly cover the top of the convex portion (22).

[0288] By forming the reflective film (30) in this manner, the convex portion (22) of the grid structure (20) and the reflective film (30) have the special tree shape described above. Thus, as described above, even when light is incident on the polarizing element (1) from an oblique direction with a relatively large and wide range of incident angles θ (e.g., 30 to 60°), the transmission axis transmittance Tp of the P-polarized light included in the incident light can be maintained at a high value, and the transmittance of the P-polarized light (transmitted light) can be secured. Therefore, since the value of Tp × Rs can be maintained at a high value (e.g., 70% or more), the polarization separation characteristics of the polarizing element (1) for incident light can be improved.

[0289] In addition, the manufacturing method of the polarizing element (1) related to the present embodiment may include, if necessary, a process of forming a protective film (40) that covers the surface of the polarizing element (1) after the reflective film forming process S16 shown in FIG. 11 (protective film forming process). It is preferable that the protective film (40) be formed to cover the entire surface of the grid structure (20) and the reflective film (30). Various materials described above may be used as the material for the protective film (40).

[0290] The above describes a method for manufacturing a polarizing element (1) related to the present embodiment. By going through the process described above, a polarizing element (1) with excellent polarizing characteristics and heat dissipation can be manufactured without causing high manufacturing costs or complexity in manufacturing.

[0291] Here, for comparison with the manufacturing method related to the present embodiment, a conventional method for manufacturing a wire grid polarizing element is briefly described with reference to FIG. 12.

[0292] As shown in FIG. 12, in a conventional method for manufacturing a wire grid polarizing element, a metal film (80) is first formed on a substrate (10) to form a convex grid shape (S20). In S20, a reflective film, such as a metal film (80) made of a material that reflects light in a usage band, such as aluminum, is formed on a substrate (10) made of an inorganic material such as glass, using sputtering or deposition.

[0293] Next, a resist mask (70) is patterned on a metal film (80) using photolithography technology (S22). Then, a convex shape formed on the metal film (80) is formed by etching the metal film (80) using a vacuum dry etching device or the like (S24). For example, if the etching selectivity ratio between the resist mask (70) and the metal film (80) cannot be achieved at this time, an oxide film such as SiO2 is additionally deposited on the metal film (80) by sputtering, and a resist mask (70) is formed on it by photolithography technology. After that, the resist mask (70) is peeled off from the metal film (80) (S26), a protective film (40) made of SiO2 film, etc. is deposited by CVD, etc., and if necessary, a water-repellent / oil-repellent coating treatment is also performed (S28).

[0294] In addition, although the processes S20 to S28 of the above conventional manufacturing method show a process for manufacturing a reflective wire grid polarizing element with a basic configuration, a more complex process is required when considering the case where the metal film (80) is a multilayer film. Therefore, it is presumed that the conventional wire grid polarizing element manufactured by the process shown in S20 to S28 of FIG. 12 will have high manufacturing costs and require a long time for manufacturing. Furthermore, when mass-producing polarizing elements, in order to form a fine convex shape smaller than the wavelength of light, it becomes necessary to prepare multiple units of high-precision etching devices or photolithography devices according to the production volume, and it is predicted that the equipment investment will also be higher.

[0295] In this regard, the manufacturing method of the polarizing element (1) related to the present embodiment (see FIG. 11) forms a grid structure (20) using an imprint technology such as nanoimprint, so the manufacturing cost, manufacturing time, and equipment investment can be significantly reduced compared to the conventional manufacturing method (see FIG. 12).

[0296] In the manufacturing method of the polarizing element (1) related to the present embodiment, a nanoimprint is performed on the grid structure material (23) (S12 in FIG. 11), and the conditions for the nanoimprint are not particularly limited. For example, as shown in S12 in FIG. 11, a replica disc (which may be a standard disc) is used as the disc (60), and while performing the nanoimprint, UV irradiation or heating is applied to the grid structure material (23) to cure the grid structure material (23) in a state where an uneven pattern is imprinted. After that, the disc (60) is released from the cured grid structure material (23). By doing so, a grid structure (20) having a base portion (21) and a convex portion (22) formed can be formed by transfer.

[0297] In addition, the disc (60) used in the nanoimprint process S12 (Fig. 11) in the method for manufacturing the polarizing element (1) related to the present embodiment can be manufactured by photolithography technology, for example, as shown in Fig. 13. Fig. 13 is a process diagram showing the method for manufacturing the disc (60) related to the present embodiment.

[0298] As shown in FIG. 13, first, a metal film (62) for a disc is formed on a disc substrate (61) (S30), and then a resist mask (70) is formed on the metal film (62) for a disc (S32). Subsequently, the metal film (62) for a disc is etched using the resist mask (70), and a concave groove (65) corresponding to the convex portion (22) of the grid structure (20) is formed on the etched metal film (62) for a disc (S34).

[0299] After that, a disc (60) is obtained by peeling off the resist mask (70) from the metal film (62) for the disc (S36). The disc (60) has a fine uneven structure formed on a plurality of convex portions (63) and concave grooves (65) formed on a substrate (61) for the disc. The fine uneven structure on the surface of the disc (60) has an inverted shape of the fine uneven structure on the surface of the grid structure (20) of the polarizing element (1). The concave grooves (65) of the disc (60) have an inverted shape of the convex portions (22) of the grid structure (20), and the convex portions (63) of the disc (60) have an inverted shape of the concave portions (24) between the convex portions (22, 22) of the grid structure (20).

[0300] Additionally, the manufacturing method related to the present embodiment may include, if necessary, a process (S38) of forming a release film coat (64) on the surface of the fine uneven structure of the disc (60). By forming a release film coat (64) on the surface of the disc (60), after performing nanoimprinting on the grid structure material (23) in the nanoimprinting process (S12) shown in FIG. 11, the disc (60) can be easily peeled off from the grid structure material (23), thereby further improving release properties.

[0301] <4. Projection Display Device>

[0302] Next, with reference to FIG. 14, a projection display device to which a wire grid polarization element (1) related to the present embodiment is applied will be described.

[0303] The projection display device related to the present embodiment is equipped with a wire grid polarization element (1) related to the present embodiment described above. By equipping the projection display device related to the present embodiment with a polarization element (1), excellent polarization characteristics and the heat resistance and heat dissipation of the polarization element (1) can be realized.

[0304] Here, a projection display device is a device that projects light toward an object and irradiates the projected light (projected light) onto the surface to be displayed (projection surface) of the object to display a virtual image such as an image or video. Examples of projection display devices include a head-up display device (HUD) and a projector device.

[0305] <4.1. Head-Up Display Device>

[0306] First, with reference to FIG. 14, a head-up display device (100) equipped with a wire grid polarizing element (1) related to the present embodiment will be described. FIG. 14 is a schematic diagram showing an example of a head-up display device (100) related to the present embodiment.

[0307] As shown in FIG. 14, the head-up display device (100) related to the present embodiment is equipped with a wire grid polarizing element (1) related to the present embodiment described above. By equipping the head-up display device (100) with a polarizing element (1), polarization characteristics, heat resistance, and heat dissipation can be improved. Since a head-up display equipped with a conventional polarizing element has poor heat dissipation, it is thought that the heat resistance is insufficient when considering long-term use or future high-brightness and enlarged display.

[0308] As shown in FIG. 14, the head-up display device (100) comprises a light source (2), a display element (3) that emits a display image, a reflector (4) that reflects the display image onto a display surface (5), and a cover portion (6) formed in an opening of a housing (7). In the head-up display device (100), the arrangement of the polarizing element (1) is not particularly limited. For example, as shown in FIG. 14, the polarizing element (1) can be arranged between the display element (3) and the reflector (4).

[0309] Here, the head-up display device (100) may be a vehicle head-up display device formed in a vehicle. The vehicle head-up display device displays an image on a semi-transparent plate (corresponding to the "display surface (5)") such as the front windshield or combiner of the vehicle. The vehicle head-up display device is, for example, an image display device that is formed by being placed on the dashboard of the vehicle, projects image light onto the front windshield (display surface (5)), and displays driving information as a virtual image.

[0310] The head-up display device (100) is configured to emit a display image from below toward the front glass surface (display surface (5)). Because of this, sunlight may penetrate in the opposite direction to the direction of emission of the display image and be incident on the display element (3). In the head-up display device (100) related to this embodiment, a reflector (4) is formed to reflect and enlarge the display image for the purpose of miniaturization or enlargement of the display image. In such cases, in conventional head-up display devices, sunlight incident on the reflector from the outside is concentrated near the display element, and there is a risk that the display element may deteriorate or malfunction due to heat.

[0311] In this regard, in the head-up display device (100) related to the present embodiment, a hybrid polarizing element (1) with excellent heat dissipation and heat resistance is formed as described above for the purpose of preventing sunlight from being incident on the display element (3). This polarizing element (1) can stably perform a polarization function even at a high temperature of, for example, about 200°C. Therefore, even in a high-temperature environment such as inside a vehicle in the summer, sunlight incident on the reflector (4) from the outside can be shielded by the polarizing element (1) to prevent it from reaching the display element (3), thereby suppressing deterioration or failure of the display element (3).

[0312] In addition, the components of the head-up display device (100) shown in FIG. 14 are examples of basic components, and the components of the projection display device are not limited to the examples in FIG. 14 and may appropriately include other components depending on the required performance, etc.

[0313] Additionally, by using the polarizing element (1) as a pre-polarizing plate placed in front of the display element (3), the polarizing element (1) can transmit the display image emitted from the display element (3) while suppressing sunlight from being incident on the display element (3). Accordingly, the heat resistance and durability of the head-up display device (100) can be further increased.

[0314] Additionally, the arrangement of the wire grid polarizing element in the projection display device is not limited to the example of the arrangement of the polarizing element (1) in the head-up display device (100) shown in FIG. 14, and can be appropriately selected and changed according to the configuration of the projection display device or the required performance. For example, although not shown, the polarizing element (1) may be placed between the display element (3) and the light source (2). Also, although not shown, the polarizing element (1) may be mounted in the reflector (4). Furthermore, the cover portion (6) formed in the head-up display device (100) shown in FIG. 14 may be composed of the polarizing element (1).

[0315] Additionally, although not in the city, a heat dissipation member (50) (see FIG. 9) may be formed around a polarizing element (1) installed in a head-up display device (100). By this heat dissipation member (50), the heat dissipation of the polarizing element (1) can be further improved, thereby further improving the polarization characteristics and heat resistance of the polarizing element (1).

[0316] <4.2. Projection display device equipped with a polarizing beam splitter>

[0317] Next, with reference to FIGS. 15 to 17, a projection display device using a reflective wire grid polarizing element (1) related to the present embodiment as a polarizing beam splitter (230) will be described. Below, first, matters common to the three specific embodiments of the projection display devices (200A, 200B, 200C) shown in FIGS. 15 to 17 (hereinafter collectively referred to as "projection display devices (200)") will be described comprehensively. After that, each specific embodiment shown in FIGS. 15 to 17 will be described individually.

[0318] As shown in FIGS. 15 to 17, the projection display device (200) comprises a light source (210), a PS converter (220), a polarizing beam splitter (230), a reflective liquid crystal display element (240), and a lens (250). Additionally, a phase difference compensation plate (not shown) may be installed between the polarizing beam splitter (230) and the reflective liquid crystal display element (240).

[0319] The light source (210) may be a point light source having one light-emitting part, or a light source having multiple light-emitting parts such as an LED. Also, the light emitted from the light source (210) may be parallel light or diffuse light. Accordingly, the light from the light source (210) may be incident on a polarizing beam splitter (230) (reflective wire grid polarizer) at an incident angle θ of a predetermined range centered at 45° (e.g., a range of 45° ± 15°).

[0320] The PS converter (220) is a polarization conversion element for converting light from a light source (210) into a specific polarization (e.g., P polarization or S polarization). The PS converter (220) may convert light from the light source (210) into P polarization or into S polarization.

[0321] The polarizing beam splitter (230) is composed of a reflective wire grid polarizer. The reflective wire grid polarizer is an example of a wire grid polarizing element (1) related to the present embodiment. The polarizing beam splitter (230) is positioned so that light from a light source (210) is incident at an incident angle θ of a predetermined range including 45°. This predetermined range of incident angle θ is, for example, the 45° ± 15° described above, i.e., 30° or more and 60° or less.

[0322] For example, in FIGS. 15 to 17, the polarizing beam splitter (230) is positioned at an angle of 45° with respect to the incident direction of the incident light so that incident light from the light source (210) is incident on the polarizing beam splitter (230) at an angle of 45°. Also, the polarizing beam splitter (230) is positioned at an angle of 45° with respect to the reflective liquid crystal display element (240) so that incident light from the reflective liquid crystal display element (240) is incident on the polarizing beam splitter (230) at an angle of 45°.

[0323] The polarizing beam splitter (230) separates incident light into a first polarization (S polarization) and a second polarization (P polarization). For example, the polarizing beam splitter (230) may separate the S polarization and the P polarization by reflecting the first polarization (S polarization) of the incident light and transmitting the second polarization (P polarization). Conversely, the polarizing beam splitter (230) may separate the S polarization and the P polarization by reflecting the second polarization (P polarization) of the incident light and transmitting the first polarization (S polarization).

[0324] When a desired polarization is reflected by a polarization beam splitter (230), the polarization beam splitter (230) is positioned so that light containing the polarization of the reflection target is incident on the surface of the polarization beam splitter (230) (i.e., the uneven surface on the side where the grid structure (20) of the polarization element (1) is formed). For example, as shown in FIG. 15, when S-polarization incident from a PS converter (220) is reflected by the polarization beam splitter (230), the surface of the polarization beam splitter (230) may be oriented toward the side of the PS converter (220) that emits S-polarization. Meanwhile, as shown in FIG. 16, when S-polarized light incident from a reflective liquid crystal display element (240) is reflected by a polarizing beam splitter (230), the surface of the polarizing beam splitter (230) may be oriented toward the reflective liquid crystal display element (240) emitting S-polarized light.

[0325] A reflective liquid crystal display element (240) is a display element that reflects incident light and emits light that displays a display image. As shown in FIG. 15 and FIG. 17, the reflective liquid crystal display element (240) may be arranged so that a first polarized light (S polarized light) reflected from a polarizing beam splitter (230) is incident on the surface of the reflective liquid crystal display element (240). Alternatively, as shown in FIG. 16, the reflective liquid crystal display element (240) may be arranged so that a second polarized light (P polarized light) transmitted through the polarizing beam splitter (230) is incident on the surface of the reflective liquid crystal display element (240).

[0326] Additionally, as shown in FIG. 15 and FIG. 17, the reflective liquid crystal display element (240) reflects and modulates the incident first polarization (S polarization) to emit a second polarization (P polarization) that displays a display image. However, it is not limited to this example, and as shown in FIG. 16, the reflective liquid crystal display element (240) may reflect and modulate the incident second polarization (P polarization) to emit a first polarization (S polarization) that displays a display image.

[0327] The lens (250) magnifies light representing a display image emitted from a reflective liquid crystal display element (240) and outputs it to the outside. The lens (250) is positioned so that light representing a display image emitted from a reflective liquid crystal display element (240) is incident through a polarizing beam splitter (230). For example, as shown in FIGS. 15 and 17, the lens (250) may be positioned so that a second polarized light (P-polarized light) reflected and modulated from a reflective liquid crystal display element (240) passes through the polarizing beam splitter (230) and is incident on the lens (250). Alternatively, as shown in FIG. 16, the lens (250) may be arranged so that the first polarization (S polarization) reflected and modulated from the reflective liquid crystal display element (240) is reflected from the polarization beam splitter (230) and incident on the lens (250).

[0328] As described above, in the projection display device (200) related to the present embodiment, the wire grid polarization element (1) related to the present embodiment described above is used as the polarization beam splitter (230). Accordingly, the polarization beam splitter (230) has excellent reflectivity of S polarization, transmittance of P polarization, and Tp × Rs characteristics for oblique incident light of a relatively large and wide range of incident angles θ (e.g., 30 to 60°), and has excellent characteristics for separating oblique incident light into P polarization and S polarization.

[0329] Next, each embodiment of the projection display device (200A, 200B, 200C) shown in FIGS. 15 to 17 will be described individually.

[0330] As shown in FIG. 15, the projection display device (200A) related to the first embodiment of the present invention comprises a light source (210), a PS converter (220), a polarizing beam splitter (230), a reflective liquid crystal display element (240), and a lens (250).

[0331] The light emitted from the light source (210) is unpolarized and contains P-polarized and S-polarized components in equal proportions. Because of this, if only one type of polarization is selected and extracted by a polarizing beam splitter (230) made of a polarizing element (1), the amount of light is reduced by about half. Therefore, the light emitted from the light source (210) is converted into either the first polarization (S-polarization) or the second polarization (P-polarization) by a PS converter (220). By doing so, the reduction in the amount of polarization extracted by the polarizing beam splitter (230) can be suppressed, thereby improving the light utilization efficiency. For example, the PS converter (220) shown in FIG. 15 converts the light from the light source (210) into the first polarization (S-polarization).

[0332] Light converted into S polarization by the PS converter (220) is incident on a polarization beam splitter (230) positioned at an oblique angle of approximately 45°. The polarization beam splitter (230) reflects the first polarization (S polarization) and emits it toward a reflective liquid crystal display element (240) at an emission angle of 45°. The reflective liquid crystal display element (240) modulates and reflects the first polarization (S polarization) to generate a second polarization (P polarization) that represents a display image, and emits the second polarization (P polarization) toward the polarization beam splitter (230). The second polarization (P polarization) passes through a polarization beam splitter (230), is magnified by a lens (250), and is projected onto a display surface where the illustration is omitted, so that a display image is displayed.

[0333] A projection display device (200A) having the above configuration is provided with a reflective wire grid polarizer made of a wire grid polarizing element (1) related to the present embodiment as a polarizing beam splitter (230). By doing so, the polarization separation characteristics of the polarizing beam splitter (230) can be improved for oblique incident light and incident light with a wide incident angle θ, and the heat dissipation and heat resistance of the polarizing beam splitter (230) and the projection display device (200A) can be improved.

[0334] In this regard, a projection display device (not shown) equipped with a conventional polarizing element as a polarizing beam splitter has poor heat dissipation of the polarizing element. For this reason, it is considered that the heat resistance is insufficient from the perspective of long-term use, high brightness, and enlarged display. In addition, the incident angle θ of light incident on the polarizing beam splitter is not only 45° but also all angles within a predetermined range centered on 45° (e.g., about 45° ± 15°). Even when obliquely incident light with a large and wide range of incident angles θ is incident on the polarizing beam splitter, the polarizing beam splitter is required to have the performance to preferably separate the obliquely incident light into S-polarized and P-polarized light regardless of the incident angle θ. However, in polarizing beam splitters using conventional polarizing elements, the polarization separation characteristics for the incident oblique light are poor, which leads to a deterioration in light utilization efficiency and causes adverse effects on the image quality of the display image, such as luminance non-uniformity.

[0335] In this regard, the polarization beam splitter (230) of the projection display device (200A) related to the first embodiment of the present invention has excellent polarization separation characteristics for incident light with an incident angle θ of a large and wide range as described above. Therefore, the light utilization efficiency in the projection display device (200A) can be improved, and brightness non-uniformity can be reduced, thereby improving the quality of the displayed image.

[0336] In addition, the projection display device is not limited to the example of the projection display device (200A) shown in FIG. 15, and the components or arrangement of the projection display device can be appropriately changed, such as the projection display device (200B) shown in FIG. 16, or the projection display device (200C) shown in FIG. 17.

[0337] As shown in FIG. 16, the projection display device (200B) related to the second embodiment of the present embodiment comprises a light source (210), a PS converter (220), a polarizing beam splitter (230), a reflective liquid crystal display element (240), and a lens (250).

[0338] In a projection display device (200B), a PS converter (220) converts light from a light source (210) into a second polarization (P polarization). The light converted into P polarization by the PS converter (220) passes through a polarization beam splitter (230) positioned at an angle of approximately 45° and is incident on a reflective liquid crystal display element (240). The reflective liquid crystal display element (240) modulates and reflects the second polarization (P polarization) to generate a first polarization (S polarization) that represents a display image, and emits the first polarization (S polarization) toward the polarization beam splitter (230). The polarizing beam splitter (230) reflects the first polarization (S polarization) and emits it toward the lens (250) at an emission angle of 45°. The first polarization (S polarization) is magnified by the lens (250) and then projected onto a display surface (not shown) to display a display image.

[0339] The projection display device (200B) having the above configuration, like the projection display device (200A) described above (see FIG. 15), has excellent polarization separation characteristics for incident light and can improve light utilization efficiency, and can also reduce brightness non-uniformity, thereby improving the quality of the displayed image.

[0340] Also, as shown in FIG. 17, the projection display device (200C) related to the third embodiment of the present embodiment is equipped with a light source (210), a polarizing beam splitter (230), a reflective liquid crystal display element (240), a lens (250), and a light absorber (260), but is not equipped with the PS converter (220).

[0341] In the projection display device (200C), the unpolarized light emitted from the light source (210) is directly incident on a polarizing beam splitter (230) that is obliquely positioned at an angle of approximately 45°. The polarizing beam splitter (230) reflects the first polarization (S polarization) component of the unpolarized light and emits it toward a reflective liquid crystal display element (240) at an emission angle of 45°. Meanwhile, the second polarization (P polarization) component of the unpolarized light incident on the polarizing beam splitter (230) passes through the polarizing beam splitter (230) and is incident on a light absorber (260). Since most of the component of this second polarization (P polarization) is absorbed by the light absorber (260), it is possible to prevent unnecessary second polarization (P polarization) from being incident on other optical systems within the projection display device (200C).

[0342] A reflective liquid crystal display element (240) modulates and reflects a component of a first polarization (S polarization) incident from a polarization beam splitter (230) to generate a second polarization (P polarization) that represents a display image, and emits the second polarization (P polarization) toward the polarization beam splitter (230). The second polarization (P polarization) passes through the polarization beam splitter (230), is magnified by a lens (250), and is projected onto a display surface (not shown) to display a display image.

[0343] In the projection display device (200C) having the above configuration, since the PS converter (220) is not installed, the component of the second polarization (P polarization) among the non-polarized light emitted from the light source (210) is absorbed by the light absorber (260) and is not used for displaying the image. Because of this, the amount of light in the image is reduced to about half. However, since the cost and installation space required for the PS converter (220) can be reduced and the number of parts of the projection display device (200C) can be reduced, there is an advantage that the cost of the projection display device (200C) can be reduced and the projection display device (200C) can be miniaturized.

[0344] Above, a specific example of a projection display device (200) using a reflective wire grid polarizing element (1) related to the present embodiment as a polarizing beam splitter (230) has been described. In addition, the projection display device is not limited to the specific example of the projection display device (200) shown in FIGS. 15 to 17, and depending on the required performance, the components or arrangement of the projection display device may be appropriately changed, or other components may be appropriately formed.

[0345] <5. Vehicles>

[0346] Next, a vehicle equipped with an image display device related to the present embodiment will be described.

[0347] The vehicle (city omitted) related to the present embodiment is equipped with a projection display device having a wire grid polarizing element (1) related to the present embodiment described above. Additionally, the vehicle may be any vehicle capable of installing a projection display device, such as a regular passenger car, a light car, a bus, a truck, a racing car, a construction vehicle, or other large vehicles, and may also be any other vehicle such as an automatic two-wheeled vehicle, a tram, a linear motor car, or an attraction vehicle.

[0348] The vehicle related to the present embodiment can project and display a display image onto a display surface formed in the vehicle (e.g., the display surface (5) shown in FIG. 14) by means of the polarizing element (1) and the projection display device. The display surface is preferably a semi-transparent plate such as, for example, the front glass, side glass, rear glass, or combiner of the vehicle. However, the display surface is not limited to these examples and may be any surface of an object capable of projecting a display image, such as a surface of various parts, components, or onboard equipment formed in the vehicle.

[0349] The projection display device formed in the vehicle related to the present embodiment is, for example, the head-up display device (100) shown in FIG. 14, or the projection display device (200) having a polarizing beam splitter (230) shown in FIG. 15 to FIG. 17. However, it is not limited to these examples, and the projection display device may be any image display device capable of projecting or displaying an image, such as a projector mounted in a vehicle, a car navigation device, or a terminal device having an image display function.

[0350] As described above, in the head-up display device (100), as shown in FIG. 14, sunlight may penetrate from the outside of the vehicle through the front glass (display surface (5)) and into the head-up display device (100). There is a risk that the heat from this sunlight may cause deterioration or failure of the display element (3). For this reason, a hybrid wire grid polarizing element (1) described above is formed in the head-up display device (100) for the purpose of preventing sunlight from being incident on the display element (3). Since this polarizing element (1) has a hybrid structure with high thermal conductivity, it has excellent heat dissipation and heat resistance. Therefore, by shielding sunlight incident from the outside into the head-up display device (100) with the polarizing element (1), it is possible to prevent it from reaching the display element (3), thereby preventing failure or damage to the display element (3). In addition, since the polarizing element (1) has excellent heat dissipation and heat resistance, damage to the polarizing element (1) itself can also be prevented.

[0351] Likewise, even when the projection display device (200) shown in FIGS. 15 to 17 is installed in a vehicle, the polarizing element (1) used as a polarizing beam splitter (230) can block sunlight from the outside, so it can prevent failure or damage to other parts such as the reflective liquid crystal display element (240). In addition, damage to the polarizing element (1) itself, which has excellent heat dissipation and heat resistance, can also be prevented.

[0352] As described above, the projection display device formed in the vehicle related to the present embodiment can achieve excellent polarization characteristics (such as solar light blocking performance or polarization separation characteristics) through the polarization element (1), and also realize excellent heat resistance and durability of the projection display device.

[0353] In addition, the vehicle is not particularly limited as long as it is equipped with the projection display device and polarizing element described above, and other conditions can be appropriately set and changed according to the performance required of the vehicle.

[0354] <6. Organic materials constituting the grid structure (Photocurable acrylic resin for imprinting)>

[0355] Next, the organic material (photocurable acrylic resin for imprinting) constituting the grid structure (20) related to the present embodiment will be described.

[0356] The photocurable acrylic resin for imprinting related to the present embodiment is an uncured resin composition. The photocurable acrylic resin for imprinting related to the present embodiment consists of a photopolymerization component and a photopolymerization initiator. The photopolymerization component related to the present embodiment is a type of acrylic polymerizable compound. In addition, the photopolymerization initiator related to the present embodiment is a substance for polymerizing the photopolymerization component and corresponds to the photocuring initiator.

[0357] <6.1. Composition of Photopolymerization Components>

[0358] Next, the composition of the photopolymerization component of the photocurable acrylic resin for imprinting related to the present embodiment will be described. The photopolymerization component related to the present embodiment comprises at least resin (A) and resin (B). In addition, the photopolymerization component related to the present embodiment may comprise resin (C) in addition to resin (A) and resin (B). Furthermore, the photopolymerization component related to the present embodiment may be composed only of resin (A) and resin (B), or may be composed only of resin (A), resin (B), and resin (C). Resins (A) to (C) will be described below.

[0359] Resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group. Resin (A) is, for example, one or both of phenylethyl acrylate and benzyl acrylate.

[0360] The resin (A) has a viscosity of 2.0 mPa·s or more and 10.0 mPa·s or less at 25°C, for example. If the resin (A) is phenylethyl acrylate, the resin (A) has a viscosity of 9.0 mPa·s at 25°C. If the resin (A) is benzyl acrylate, the resin (A) has a viscosity of 2.2 mPa·s at 25°C. In addition, the viscosity is the viscosity of the liquid using a rotational viscometer and a vibratory viscometer in accordance with JIS Z8803. The viscosity is measured using a cone plate, for example, in the product name "Brookfield Viscometer" manufactured by Eiko Seiki Co., Ltd.

[0361] Resin (B) is a difunctional compound. Resin (B) is, for example, a difunctional acrylate monomer. Resin (B) is, for example, one or more selected from the group consisting of (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene, and 1,6-hexanediol diacrylate. It is preferable that Resin (B) comprises 1,6-hexanediol diacrylate, and one of (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, and bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene.

[0362] (Octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate is a difunctional acrylate monomer represented by the following chemical formula (I). For example, the product name "KAYARAD R-684" manufactured by Nippon Fire & Marine Insurance Co., Ltd. can be used as (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate.

[0363] [Chemical Formula 1]

[0364]

[0365] Bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene is a difunctional acrylate monomer represented by the following chemical formula (II). For example, Bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene can be used under the product name "KAYARAD R-604" manufactured by Nippon Explosives Co., Ltd.

[0366] [Chemical Formula 2]

[0367]

[0368] 1,6-hexanediol diacrylate is a difunctional acrylate monomer represented by the following chemical formula (III). For example, 1,6-hexanediol diacrylate can be used under the product name "A-HD-N" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

[0369] CH2=CHCOO(CH2)6OOCCH=CH2… (III)

[0370] The resin (B) has a viscosity of 5.0 mPa·s or more and 500 mPa·s or less at 25°C, for example. If the resin (B) is (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, the resin (B) has a viscosity of 100 mPa·s or more and 250 mPa·s or less at 25°C. If the resin (B) is bisacrylic acid(2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene, the resin (B) has a viscosity of 200 mPa·s or more and 400 mPa·s or less at 25°C. When the resin (B) is 1,6-hexanediol diacrylate, the resin (B) has a viscosity of 6.5 mPa·s at 25 ℃.

[0371] The resin (C) is, for example, an acrylate monomer having three or more functional groups. The resin (C) comprises, for example, one or both of dipentaerythritol hexaacrylate and tris-(2-acryloxyethyl)isocyanurate. For dipentaerythritol hexaacrylate, for example, the product name "KAYARAD DPHA" manufactured by Nippon Explosives Co., Ltd. may be used. For tris-(2-acryloxyethyl)isocyanurate, for example, the product name "A-9300S" manufactured by Shin-Nakamura Chemical Industry Co., Ltd. may be used.

[0372] The resin (C) has a viscosity of 1,000 mPa·s or more and 12,000 mPa·s or less at 25°C, for example. If the resin (C) is dipentaerythritol hexaacrylate, the resin (C) has a viscosity of 5,000 mPa·s or more and 10,000 mPa·s or less at 25°C. If the resin (C) is tris-(2-acryloxyethyl)isocyanurate, the resin (C) has a viscosity of 1,000 mPa·s at 50°C.

[0373] <6.2. Content of each resin in the total photopolymerization components>

[0374] Next, the content of each resin in the entire photopolymerization component related to the present embodiment will be described. In the present embodiment, the content of resin (A) in the entire photopolymerization component is 20 mass% or more, preferably 23 mass% or more. The content of resin (A) in the entire photopolymerization component is 42 mass% or less, preferably 35 mass% or less, and more preferably 30 mass% or less. The content of resin (A) in the entire photopolymerization component is 20 mass% or more and 42 mass% or less, preferably 20 mass% or more and 35 mass% or less, and more preferably 20 mass% or more and 30 mass% or less.

[0375] In addition, in the present embodiment, the content of resin (B) relative to the total photopolymerization component is 43 mass% or more, preferably 45 mass% or more. The content of resin (B) relative to the total photopolymerization component is 66 mass% or less, preferably 60 mass% or less. The content of resin (B) relative to the total photopolymerization component is 43 mass% or more and 66 mass% or less, preferably 45 mass% or more and 66 mass% or less, and more preferably 45 mass% or more and 60 mass% or less.

[0376] In addition, in the present embodiment, the content of resin (C) relative to the total photopolymerization component is, for example, 1 mass% or more, preferably 10 mass% or more, and more preferably 15 mass% or more. The content of resin (C) relative to the total photopolymerization component is, for example, 30 mass% or less, and preferably 20 mass% or less. The content of resin (C) relative to the total photopolymerization component is, for example, 1 mass% or more and 30 mass% or less, and preferably 10 mass% or more and 20 mass% or less.

[0377] In addition, in the present embodiment, the total content of resin (A) and resin (B) with respect to the entire photopolymerization component is, for example, 70 mass% or more, preferably 80 mass% or more, and more preferably 85 mass%. The total content of resin (A) and resin (B) with respect to the entire photopolymerization component is, for example, 99 mass% or less, and preferably 90 mass% or less. The total content of resin (A) and resin (B) with respect to the entire photopolymerization component is, for example, 70 mass% or more and 99 mass% or less, and preferably 80 mass% or more and 90 mass% or less.

[0378] In addition, in the present embodiment, the total content of resin (A) and resin (C) with respect to the entire photopolymerization component is, for example, 34 mass% or more, and preferably 40 mass% or more. The total content of resin (A) and resin (C) with respect to the entire photopolymerization component is, for example, 57 mass% or less, and preferably 54 mass% or less. The total content of resin (A) and resin (C) with respect to the entire photopolymerization component is, for example, 34 mass% or more and 57 mass% or less, and preferably 40 mass% or more and 54 mass% or less.

[0379] In addition, in the present embodiment, the total content of resin (B) and resin (C) with respect to the entire photopolymerization component is, for example, 58 mass% or more, preferably 67 mass% or more, and more preferably 70 mass% or more. The total content of resin (B) and resin (C) with respect to the entire photopolymerization component is, for example, 80 mass% or less, and preferably 77 mass% or less. The total content of resin (B) and resin (C) with respect to the entire photopolymerization component is, for example, 58 mass% or more and 80 mass% or less, and preferably 67 mass% or more and 77 mass% or less.

[0380] In addition, in the present embodiment, the content of the resin having a viscosity of 20 mPa·s or less at 25°C relative to the total photopolymerization component is, for example, 43 mass% or more, preferably 46 mass% or more, and more preferably 50 mass% or more. The content of the resin having a viscosity of 20 mPa·s or less at 25°C relative to the total photopolymerization component is, for example, 84 mass% or less, preferably 66 mass% or less, and more preferably 60 mass% or less. The content of the resin having a viscosity of 20 mPa·s or less at 25°C relative to the total photopolymerization component is 43 mass% or more and 84 mass% or less, preferably 46 mass% or more and 66 mass% or less, and more preferably 50 mass% or more and 60 mass% or less.

[0381] <6.3. Photopolymerization Initiator>

[0382] Next, the photopolymerization initiator related to the present embodiment will be described. The photopolymerization initiator related to the present embodiment is, for example, an acylphosphine oxide-based photopolymerization initiator or an alkylphenone-based photopolymerization initiator. As a photopolymerization initiator, for example, the product name "Irgacure819" manufactured by IGM Resins BV can be used.

[0383] In a photocurable acrylic resin for imprinting, when the total content of the photopolymerization component is 100 mass%, the content of the photopolymerization initiator is preferably 0.5 mass% or more, and more preferably 1 mass% or more. In a photocurable acrylic resin for imprinting, when the total content of the photopolymerization component is 100 mass%, the content of the photopolymerization initiator is preferably 3 mass% or less. In a photocurable acrylic resin for imprinting, when the total content of the photopolymerization component is 100 mass%, the content of the photopolymerization initiator is preferably 0.5 mass% or more and 3 mass% or less, and more preferably 1 mass% or more and 3 mass% or less.

[0384] <6.4. Viscosity of Photocurable Acrylic Resin for Imprinting>

[0385] Next, the viscosity of the photocurable acrylic resin for imprinting related to the present embodiment will be described. Due to the relationship of the content ratios of resin (A), resin (B), and resin (C) shown in 6.2 above, the viscosity of the photocurable acrylic resin for imprinting at 25°C is, for example, 90 mPa·s or less, preferably 70 mPa·s or less, and more preferably 30 mPa·s or less. The viscosity of the photocurable acrylic resin for imprinting at 25°C is, for example, 10 mPa·s or more. The viscosity of the photocurable acrylic resin for imprinting at 25°C is, for example, 10 mPa·s or more and 90 mPa·s or less, preferably 10 mPa·s or more and 70 mPa·s or less, and more preferably 10 mPa·s or more and 30 mPa·s or less.

[0386] <6.5. YI Value of Cured Photocurable Acrylic Resin for Imprinting>

[0387] Next, the YI (Yellow Index) value of the cured product obtained by irradiating light (e.g., ultraviolet light) onto the photocurable acrylic resin for imprinting related to the present embodiment will be described. The YI value is calculated based on JIS K 7373:2006 “Plastics—Determination of yellowness index and change of yellowness index.” The YI value is calculated, for example, from the measurement results using the product name “Ultraviolet-Visible-Near-Infrared Spectrophotometer V-770” manufactured by Nippon Sensing Co., Ltd. Specifically, using the Ultraviolet-Visible-Near-Infrared Spectrophotometer V-770, a D65 light source is used to measure the transmittance of the cured product for light in the wavelength range of 380 nm to 800 nm at 0° incidence. Then, based on the measurement results, color calculation is performed by software, and X, Y, and Z of the XYZ color system are calculated. By substituting the X, Y, and Z values ​​of the calculated XYZ color system into the following equation (3) shown in JIS K 7373:2006, the YI value is calculated.

[0388] YI = 100 × (1.2985X - 1.1335Z) / Y... (3)

[0389] After maintaining the cured product of the photocurable acrylic resin for imprinting related to the present embodiment at 150°C for 500 hours, it is preferable that the YI value of the cured product be 0 or higher. After maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the YI value of the cured product may be 3.0 or lower, preferably 2.5 or lower, more preferably 2.0 or lower, and even more preferably 1.4 or lower. After maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the YI value of the cured product may be 0.0 or higher and 3.0 or lower, preferably 0.0 or higher and 2.5 or lower, more preferably 0.0 or higher and 2.0 or lower, and even more preferably 0.0 or higher and 1.4 or lower.

[0390] <6.6. Average Transmittance of Cured Photocurable Acrylic Resin for Imprinting>

[0391] Next, the average transmittance of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment will be described. The average transmittance is calculated by measuring the transmittance for every 1 nm in the wavelength range of 430 nm or more and 680 nm or less, and by simply averaging the 251 obtained measurement data. The transmittance is measured, for example, using the product name "UV-Visible-Near-Infrared Spectrophotometer V-770" manufactured by Nippon Sensing Co., Ltd.

[0392] When the cured product of the photocurable acrylic resin for imprinting related to the present embodiment is maintained at 150°C for 500 hours, the average transmittance of the cured product to light in a wavelength range of 430 nm or more and 680 nm or less may be 91% or more, preferably 91.5% or more, and more preferably 92% or more. When the cured product of the photocurable acrylic resin for imprinting is maintained at 150°C for 500 hours, the average transmittance of the cured product to light in a wavelength range of 430 nm or more and 680 nm or less may be 93% or less. After maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the average transmittance of the cured product for light in the wavelength range of 430 nm or more and 680 nm or less may be 91% or more and 93% or less, preferably 91.5% or more and 92% or less, and more preferably 92% or more and 93% or less.

[0393] In addition, the difference in average transmittance of the cured product (|average transmittance before maintenance - average transmittance after maintenance|) with respect to light in a wavelength range of 430 nm or more and 680 nm or less, before and after maintaining the cured product of the photocurable acrylic resin for imprinting related to the present embodiment at 150°C for 500 hours, may be -0.2% or more. The difference in average transmittance of the cured product (|average transmittance before maintenance - average transmittance after maintenance|) with respect to light in a wavelength range of 430 nm or more and 680 nm or less, before and after maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, may be 0.6% or less, preferably 0.5% or less, and more preferably 0.2% or less. The difference in average transmittance of the cured product of a photocurable acrylic resin for imprinting with respect to light in a wavelength range of 430 nm or more and 680 nm or less (|average transmittance before maintenance - average transmittance after maintenance|) before and after maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours may be -0.2% or more and 0.6% or less, preferably -0.2% or more and 0.5% or less, and more preferably -0.2% or more and 0.2% or less.

[0394] When the cured product of the photocurable acrylic resin for imprinting related to the present embodiment is maintained at 150°C for 500 hours, the average transmittance of the cured product to light in a wavelength range of 430 nm or more and 510 nm or less may be 90% or more, and preferably 91% or more. When the cured product of the photocurable acrylic resin for imprinting is maintained at 150°C for 500 hours, the average transmittance of the cured product to light in a wavelength range of 430 nm or more and 510 nm or less may be 92% or less. After maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours, the average transmittance of the cured product for light in a wavelength range of 430 nm or more and 510 nm or less may be 90% or more and 92% or less, and preferably 91% or more and 92% or less.

[0395] In addition, the difference in average transmittance of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment with respect to light in a wavelength range of 430 nm or more and 510 nm or less before and after maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours (|average transmittance before maintenance - average transmittance after maintenance|) may be 0.0% or more. The difference in average transmittance of the cured product of the photocurable acrylic resin for imprinting with respect to light in a wavelength range of 430 nm or more and 510 nm or less before and after maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours (|average transmittance before maintenance - average transmittance after maintenance|) may be 1.6% or less, preferably 1.1% or less, and more preferably 0.5% or less. The difference in the average transmittance of the cured product of the photocurable acrylic resin for imprinting with respect to light in the wavelength range of 430 nm or more and 510 nm or less (|average transmittance before maintenance - average transmittance after maintenance|) before and after maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours may be 0.0% or more and 1.6% or less, preferably 0.0% or more and 1.1% or less, and more preferably 0.0% or more and 0.5% or less.

[0396] <6.7. Storage Modulus of Cured Photocurable Acrylic Resin for Imprinting>

[0397] Next, the storage modulus of the cured product of the photocurable acrylic resin for imprinting will be described. Storage modulus is the component of energy generated by external force and deformation that is stored within the object. In short, storage modulus indicates the hardness of the cured product. The higher the storage modulus, the harder the cured product. Storage modulus can be measured, for example, using the “DMA7100” manufactured by Hitachi High-Tech Inc. For example, a sheet of the cured product can be cut to a length of 20 mm × width of 3 mm, and in tensile mode, the temperature can be raised at a constant frequency (1 Hz) and a rate of 5 ℃ / min to measure the storage modulus at 25 ℃ to 300 ℃.

[0398] At 30 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment is 2.0 × 10 9 It may be Pa or greater, and preferably 2.5 × 10 9 Pa or more, and more preferably, 3.0 × 10 9 It is greater than Pa. At 30 ℃, the storage modulus of the cured photocurable acrylic resin for imprinting is 3.2 × 10⁻⁶ 9 It may be Pa or less. At 30 ℃, the storage modulus of the cured photocurable acrylic resin for imprinting is 2.0 × 10⁻⁶ 9 Pa or greater, 3.2 × 10⁻⁶ 9 It may be Pa or less, and preferably 2.5 × 10 9 Pa or greater, 3.2 × 10⁻⁶ 9 Pa or less, and more preferably, 3.0 × 10 9 Pa or greater, 3.2 × 10⁻⁶ 9 Pa is less than or equal to

[0399] At 110 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment is 1.3 × 10 8 It may be Pa or more, and preferably 1.5 × 10 8Pa or more, and more preferably, 3.0 × 10 8 Pa or more, and more preferably, 5.0 × 10 8 It is Pa or higher. At 110 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment is 1.1 × 10⁻⁶ 9 It may be Pa or less. At 110 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment is 1.3 × 10 8 Pa or greater, 1.1 × 10 9 It may be Pa or less, and preferably 1.5 × 10 8 Pa or greater, 1.1 × 10 9 Pa or less, and more preferably, 3.0 × 10 8 Pa or greater, 1.1 × 10 9 Pa or less, and more preferably, 5.0 × 10 8 Pa or greater, 1.1 × 10 9 Pa is less than or equal to

[0400] At 120 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment is 1.3 × 10⁻⁶ 8 It may be Pa or greater, and preferably 3.0 × 10 8 Pa or more, and more preferably, 5.0 × 10 8 It is greater than Pa. At 120 ℃, the storage modulus of the cured photocurable acrylic resin for imprinting is 9.1 × 10⁻⁶ 8 It may be Pa or less. At 120 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting is 1.3 × 10⁻⁶ 8 Pa or greater, 9.1 × 10 8 It may be Pa or less, and preferably 3.0 × 10 8 Pa or greater, 9.1 × 10 8 Pa or less, and more preferably, 5.0 × 10 8Pa or greater, 9.1 × 10 8 Pa is less than or equal to

[0401] At 130 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment is 1.4 × 10⁻⁶ 8 It may be Pa or higher, and preferably 2.0 × 10 8 Pa or more, and more preferably, 7.0 × 10 8 It is greater than Pa. At 130 ℃, the storage modulus of the cured photocurable acrylic resin for imprinting is 8.0 × 10⁻⁶ 8 It may be Pa or less. At 130 ℃, the storage modulus of the cured product of the photocurable acrylic resin for imprinting is 1.4 × 10⁻⁶ 8 Pa or higher, 8.0 × 10 8 It may be Pa or less, and preferably 2.0 × 10 8 Pa or greater, 8.0 × 10 8 Pa or less, and more preferably, 7.0 × 10 8 Pa or higher, 8.0 × 10 8 Pa is less than or equal to

[0402] <6.8. Glass Transition Temperature Tg of Cured Photocurable Acrylic Resin for Imprinting>

[0403] Next, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting will be described. The glass transition temperature Tg can be measured, for example, using the product name "DMA7100" manufactured by Hitachi High-Tech Co., Ltd. For example, the cured product sheet can be cut to a length of 20 mm × width of 3 mm, and in tensile mode, the temperature can be increased at a constant frequency (1 Hz) at a rate of 5 ℃ / min to measure the maximum value of the loss tangent tan δ at 25 ℃ to 300 ℃.

[0404] The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting related to the present embodiment may be 58°C or higher, preferably 80°C or higher, and more preferably 100°C or higher. The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting may be 181°C or lower. The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting may be 58°C or higher and 110°C or lower, preferably 80°C or higher and 110°C or lower, and more preferably 100°C or higher and 110°C or lower.

[0405] <6.9. Method for Manufacturing Photocurable Acrylic Resin for Imprinting>

[0406] Next, a method for manufacturing a photocurable acrylic resin for imprinting related to the present embodiment will be described.

[0407] The method for manufacturing a photocurable acrylic resin for imprinting related to the present embodiment preferably involves mixing a plurality of types of resins included in the photopolymerization component, and then mixing a powdered photopolymerization initiator into the mixed resin of the plurality of types of resins. For example, when the photopolymerization component includes resin (A) and resin (B), the method for manufacturing a photocurable acrylic resin for imprinting comprises mixing resin (A) and resin (B) and mixing a photopolymerization initiator into the mixed resin of resin (A) and resin (B). Additionally, when the photopolymerization component includes resin (A), resin (B), and resin (C), the method for manufacturing a photocurable acrylic resin for imprinting comprises mixing resin (A), resin (B), and resin (C), and mixing a photopolymerization initiator into the mixed resin of resin (A), resin (B), and resin (C).

[0408] In addition, when the photopolymerization component includes multiple types of resins, the method for manufacturing a photocurable acrylic resin for imprinting preferably produces a mixed resin by mixing, in order, the resin having low viscosity among the multiple types of resins included in the photopolymerization component. For example, when the photopolymerization component includes resin (A), resin (B), and resin (C), the method for manufacturing a photocurable acrylic resin for imprinting includes producing a first mixed resin by mixing resin (A) and resin (B), and producing a second mixed resin by mixing resin (C) with the first mixed resin. Furthermore, it is preferable to mix a photopolymerization initiator into the second mixed resin.

[0409] In addition, the method for manufacturing photocurable acrylic resin for imprinting can be, for example, by using a rotating or orbiting mixer.

[0410] <6.10. Effects of Photocurable Acrylic Resin for Imprinting>

[0411] As described above, the photocurable acrylic resin for imprinting related to the present embodiment is a photocurable acrylic resin for imprinting comprising a photopolymerization component, wherein the photopolymerization component comprises resin (A) and resin (B), resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and resin (B) is a difunctional compound, wherein the content of resin (A) relative to the total photopolymerization component is 20 mass% or more and 42 mass% or less, and the content of resin (B) relative to the total photopolymerization component is 43 mass% or more and 66 mass% or less.

[0412] As such, the photocurable acrylic resin for imprinting related to the present embodiment comprises resin (A). Resin (A) has one or both of a phenyl group and a benzyl group. Because of this, resin (A) has low steric hindrance and high reactivity. Therefore, in the photocurable acrylic resin for imprinting related to the present embodiment, even if the cured product of the photocurable acrylic resin for imprinting is heated, the decomposition of the cured product can be suppressed by the interaction of the terminal directional rings. Accordingly, the photocurable acrylic resin for imprinting related to the present embodiment can improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0413] A large accompaniment to the accompaniment of

[0414] In addition, the photocurable acrylic resin for imprinting related to the present embodiment includes resin (B). By doing so, the photocurable acrylic resin for imprinting related to the present embodiment can improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0415] In addition, as described above, in the photocurable acrylic resin for imprinting related to the present embodiment, the content of resin (A) relative to the total photopolymerization component is 20 mass% or more and 42 mass% or less, and the content of resin (B) relative to the total photopolymerization component is 43 mass% or more and 66 mass% or less. Thus, the photocurable acrylic resin for imprinting related to the present embodiment can achieve both low viscosity and improved heat resistance of the cured product.

[0416] Since the photocurable acrylic resin for imprinting related to this embodiment has low viscosity, the thickness (layer thickness) of the photocurable acrylic resin layer for imprinting can be made uniform when the disc (60) is pressed against the photocurable acrylic resin for imprinting (organic material) in the nanoimprinting process S12 (Fig. 11). As a result, it is possible to make the peeling force applied when peeling the disc (60) from the layer of the photocurable acrylic resin for imprinting uniform within the plane. Therefore, the situation in which the layer of the photocurable acrylic resin for imprinting peels off from the substrate (10) can be avoided. Because of this, the residue of the layer of the photocurable acrylic resin for imprinting on the disc (60) can be suppressed, making it possible to reuse the disc (60). In addition, since the peeling force can be made uniform within the plane, it is possible to avoid the situation where the fine irregular shape transferred to the layer of the cured photocurable acrylic resin for imprinting is deformed when peeling off the disc (60). Because of this, the degradation of optical properties caused by the fine irregular shape of the cured product of the photocurable acrylic resin for imprinting can be suppressed. Therefore, when a grid structure (20) is manufactured using the cured product of the photocurable acrylic resin for imprinting, it is possible to suppress the degradation of the polarization properties of the grid structure (20).

[0417] In addition, since the photocurable acrylic resin for imprinting related to the present embodiment has low viscosity, the following ability of the photocurable acrylic resin for imprinting to the fine irregular shape of the disc (60) can be improved when the disc (60) is pressed against the photocurable acrylic resin for imprinting in the nanoimprinting process S12. Accordingly, in the nanoimprinting process S12, it becomes possible to evenly transfer the fine irregular shape of the disc (60) to the layer of the photocurable acrylic resin for imprinting.

[0418] In addition, since the photocurable acrylic resin for imprinting related to this embodiment has low viscosity, the incorporation of bubbles into the photocurable acrylic resin for imprinting during the nanoimprinting process S12 can be suppressed. As a result, it is possible to avoid a situation where a part of the fine irregular shape in the cured product of the photocurable acrylic resin for imprinting is broken off by bubbles. Therefore, when a grid structure (20) is manufactured using the cured product of the photocurable acrylic resin for imprinting, the breakage of the convex portion (22) of the grid structure (20) can be suppressed.

[0419] The cured product of the photocurable acrylic resin for imprinting related to this embodiment has superior heat resistance. Therefore, when an optical material (e.g., the grid structure (20) of the wire grid polarizing element (1)) is manufactured using the cured product of the photocurable acrylic resin for imprinting, even if additional heat treatment such as deposition is performed on the optical material, the degradation of the optical properties of the optical material can be further suppressed.

[0420] In addition, as described above, the photopolymerization component may further include a resin (C), and the resin (C) is an acrylate monomer having three or more functional groups, and the content of the resin (C) relative to the total photopolymerization component may be 1 mass% or more and 30 mass% or less.

[0421] Thus, the photocurable acrylic resin for imprinting related to the present embodiment can increase the crosslinking density during curing and suppress the decrease in storage modulus of the cured product of the photocurable acrylic resin for imprinting at high temperatures. In addition, as described above, in the photocurable acrylic resin for imprinting related to the present embodiment, it is preferable that the content of resin (C) relative to the total photopolymerization component is 1 mass% or more and 30 mass% or less. This further suppresses the decrease in storage modulus of the cured product of the photocurable acrylic resin for imprinting at high temperatures.

[0422] Also, as described above, the resin (A) may be one or both of phenylethyl acrylate and benzyl acrylate.

[0423] Thus, the photocurable acrylic resin for imprinting related to the present embodiment can further improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting. In addition, in this case, the resin (A) has a viscosity of 9.0 mPa·s or less at 25°C. Because of this, the viscosity of the photocurable acrylic resin for imprinting related to the present embodiment can be lowered.

[0424] In addition, as described above, the resin (B) may be one or more selected from the group consisting of (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene, and 1,6-hexanedioldiacrylate.

[0425] Thus, the photocurable acrylic resin for imprinting related to the present embodiment can further improve the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0426] In addition, as described above, the resin (B) may comprise one of 1,6-hexanediol diacrylate, (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, and bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene.

[0427] By doing so, the viscosity of the photocurable acrylic resin for imprinting can be lowered, and the heat resistance of the photocurable acrylic resin for imprinting can be further improved.

[0428] In addition, as described above, the resin (C) may comprise one or both of dipentaerythritol hexaacrylate and tris-(2-acryloxyethyl)isocyanurate.

[0429] Thus, the decrease in storage modulus of the cured product of the photocurable acrylic resin for imprinting at high temperatures can be further suppressed.

[0430] In addition, as described above, the viscosity of the photocurable acrylic resin for imprinting at 25°C may be 90 mPa·s or less.

[0431] Thus, in the above nanoimprint process S12, when a disc (60) is pressed against the photocurable acrylic resin for imprint, the thickness of the layer of the photocurable acrylic resin for imprint can be made more uniform, the following ability of the photocurable acrylic resin for imprint to the fine irregular shape of the disc (60) can be further improved, and the incorporation of bubbles into the photocurable acrylic resin for imprint can be further suppressed.

[0432] In addition, as described above, in the photocurable acrylic resin for imprinting related to the present embodiment, by setting the content of resin (A) relative to the total photopolymerization component to 20 mass% or more and 42 mass% or less, and the content of resin (B) relative to the total photopolymerization component to 43 mass% or more and 66 mass% or less, the viscosity of the photocurable acrylic resin for imprinting at 25°C can be 90 mPa·s or less.

[0433] For example, since the cured product of the photocurable acrylic resin for imprinting related to the present embodiment has excellent heat resistance, the YI value of the cured product of the photocurable acrylic resin for imprinting becomes 3 or less after maintaining the cured product of the photocurable acrylic resin for imprinting at 150°C for 500 hours. Therefore, by manufacturing an optical material using the cured product of the photocurable acrylic resin for imprinting, even if additional heat treatment such as deposition is performed on the optical material, yellowing of the optical material can be suppressed and transparency can be maintained.

[0434] Also, as described above, the storage modulus of the cured product of the photocurable acrylic resin for imprinting at 30 ℃ is 2.0 × 10⁻⁶ 9 It may be considered as Pa or higher.

[0435] Thus, in the above nanoimprint process S12 (Fig. 11), when peeling off the disc (60), it becomes possible to further avoid the situation where the micro-irregular shape transferred to the layer of the cured photocurable acrylic resin for imprinting becomes deformed. Because of this, the degradation of optical properties caused by the micro-irregular shape of the cured product of the photocurable acrylic resin for imprinting can be further suppressed. Therefore, when a grid structure (20) is manufactured using the cured product of the photocurable acrylic resin for imprinting, it becomes possible to further suppress the degradation of the polarization properties of the grid structure (20).

[0436] Also, for example, since the cured product of the photocurable acrylic resin for imprinting related to the present embodiment has excellent heat resistance, the storage modulus of said cured product at 120°C is 1.3 × 10⁻⁶ 8 It may be Pa or higher. Therefore, by manufacturing an optical material from a cured photocurable acrylic resin for imprinting, deformation of the optical material can be further suppressed even if additional heat treatments, such as deposition, are performed on the optical material. As a result, it becomes possible to further suppress the degradation of the optical properties of the optical material.

[0437] Also, for example, since the cured product of the photocurable acrylic resin for imprinting related to the present embodiment has superior heat resistance, the storage modulus of said cured product at 130°C is 1.4 × 10⁻⁶ 8It may be Pa or higher. Therefore, by manufacturing an optical material from a cured product of a photocurable acrylic resin for imprinting, deformation of the optical material can be suppressed more preferably even if additional heat treatment, such as deposition, is performed on the optical material. Because of this, it becomes possible to suppress the degradation of the optical properties of the optical material more preferably.

[0438] In addition, for example, since the cured product of the photocurable acrylic resin for imprinting related to the present embodiment has superior heat resistance, the average transmittance of the cured product for imprinting to light in the wavelength range of 430 nm or more and 680 nm or less is 91% or more after maintaining the cured product for imprinting at 150°C for 500 hours. Therefore, by manufacturing an optical material using the cured product of the photocurable acrylic resin for imprinting, even if additional heat treatment such as deposition is performed on the optical material, the average transmittance of the optical material to light in the above wavelength range can be maintained at a higher level.

[0439] In addition, for example, since the cured product of the photocurable acrylic resin for imprinting related to the present embodiment has superior heat resistance, the average transmittance of the cured product for imprinting to light in the wavelength range of 430 nm or more and 510 nm or less is 90% or more after maintaining the cured product for imprinting at 120°C for 500 hours. Therefore, by manufacturing an optical material using the cured product of the photocurable acrylic resin for imprinting, even if additional heat treatment such as deposition is performed on the optical material, the average transmittance of the optical material to light in the above wavelength range can be maintained at a higher level.

[0440] Also, as described above, when manufacturing a wire grid polarizing element (1), a reflective film (30) is deposited on a grid structure (20). When the reflective film (30) is deposited, the grid structure (20) is heated. Here, if the heat resistance of the grid structure (20) is low, there is a problem that the grid structure (20) is deformed when the reflective film (30) is deposited, and the polarization characteristics are degraded.

[0441] However, the cured product of the photocurable acrylic resin for imprinting related to the present embodiment has superior heat resistance. Therefore, by manufacturing the grid structure (20) with the cured product of the photocurable acrylic resin for imprinting, yellowing of the grid structure (20) and deformation of the grid structure (20) can be further suppressed even when a reflective film (30) is deposited, and the average transmittance of the grid structure (20) for light in the wavelength range of 430 nm or more and 680 nm or less and light in the wavelength range of 430 nm or more and 510 nm or less can be maintained at a higher level. Because of this, it becomes possible to suppress the deterioration of the polarization characteristics of the grid structure (20) more preferably.

[0442] In addition, as described above, in the photocurable acrylic resin for imprinting related to the present embodiment, it is preferable that the content of resin (C) relative to the total photopolymerization component is 1 mass% or more and 30 mass% or less. By doing so, the heat resistance of the photocurable acrylic resin for imprinting related to the present embodiment can be further improved. For example, the storage modulus of the cured product of the photocurable acrylic resin for imprinting at 120°C is 1.3 × 10⁻⁶ 8 The storage modulus of the cured product of the photocurable acrylic resin for imprinting, which can be Pa or greater, at 130 ℃ is 1.4 × 10⁻⁶ 8 It can be done beyond Pa.

[0443] In addition, as described above, in a method for manufacturing a photocurable acrylic resin for imprinting that includes a photopolymerization component and a photopolymerization initiator for polymerizing the photopolymerization component related to the present embodiment, the photopolymerization component comprises a resin (A) and a resin (B), wherein the resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and the resin (B) is a difunctional compound, wherein the content of the resin (A) relative to the total photopolymerization component is 20 mass% or more and 42 mass% or less, and the content of the resin (B) relative to the total photopolymerization component is 43 mass% or more and 66 mass% or less, and the method comprises mixing the resin (A) and the resin (B), and mixing a photopolymerization initiator into the mixed resin of the resin (A) and the resin (B).

[0444] Thus, the photopolymerization component and the photopolymerization initiator can be preferably mixed. Accordingly, the photopolymerization component can be cured evenly (without non-uniformity). For this reason, it becomes possible to achieve uniform heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0445] In addition, as described above, in a method for manufacturing a photocurable acrylic resin for imprinting comprising a photopolymerization component related to the present embodiment, the photopolymerization component comprises resin (A), resin (B), and resin (C), wherein resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, resin (B) is a difunctional compound, and resin (C) is an acrylate monomer having three or more functional groups, wherein the content of resin (A) relative to the total photopolymerization component is 20 mass% or more and 42 mass% or less, the content of resin (B) relative to the total photopolymerization component is 43 mass% or more and 66 mass% or less, and the content of resin (C) relative to the total photopolymerization component is 1 mass% or more and 30 mass% or less, and a first mixed resin is produced by mixing resin (A) and resin (B), and a first It includes producing a second mixed resin by mixing resin (C) into the mixed resin.

[0446] Thus, resin (A), resin (B), and resin (C) can be preferably mixed. Accordingly, it is possible to achieve uniformity in the viscosity of the photocurable acrylic resin for imprinting. In addition, it is possible to further achieve uniformity in the heat resistance of the cured product of the photocurable acrylic resin for imprinting.

[0447] <6.11. Other Ingredients>

[0448] The photocurable acrylic resin for imprinting may contain other components (additives) to the extent that they do not impair the effects described in 6.10 above. Other components include, for example, antioxidants, phosphors, plasticizers, UV absorbers, antifoaming agents, thixotropic agents, polymerization inhibitors, release agents, metal oxide particles, etc.

[0449] <7. Grid Slope Structure>

[0450] Next, with reference to FIGS. 18 and 19, a wire grid polarizing element (1) having a grid slope structure related to a second embodiment of the present invention will be described. FIG. 18 is a cross-sectional view schematically showing the grid slope structure of the wire grid polarizing element (1) related to the second embodiment. FIG. 19 is a cross-sectional view schematically showing an example of modification of the grid slope structure of the wire grid polarizing element (1) related to the second embodiment.

[0451] As shown in FIGS. 18 and 19, the grid structure (20) of the wire grid polarizing element (1) (hereinafter referred to as "polarizing element (1)") related to the second embodiment has a grid inclination structure. The grid inclination structure is a structure in which a plurality of convex portions (22) constituting the grid structure (20) are partially or entirely inclined in the width direction (X direction) of the convex portions (22). This grid inclination structure will be explained in more detail below.

[0452] The polarizing element (1) related to the second embodiment, like the polarizing element (1) related to the first embodiment described above (see FIG. 1, etc.), comprises a substrate (10) made of an inorganic material, a grid structure (20) made of an organic material, and a reflective film (30) (functional film) made of a metal material. The grid structure (20) is a resin structure in which a flat base portion (21) formed on the substrate (10) and a plurality of convex jaw portions (22) protruding from the base portion (21) are integrally formed. The convex jaw portions (22) have a shape that tapers toward the end, with the width in the X direction narrowing as they move away from the base portion (21).

[0453] Here, in the grid structure (20) related to the first embodiment described above, as shown in FIG. 1, etc., the convex portion (22) protrudes straight upward along the normal direction (Z direction) of the surface (XY plane) of the substrate (10) and is not inclined in the width direction (X direction) of the convex portion (22) with respect to the normal direction (Z direction) of the substrate (10). In short, the central axis of the convex portion (22) (an axis passing through the center of the width direction (X direction) of the convex portion (22) and extending in the height direction (Z direction) of the convex portion (22)) is generally perpendicular to the surface (XY plane) of the substrate (10) and generally parallel to the normal direction (Z direction) of the substrate (10). Also, the central axis of the convex part (22) is an axis that passes through the center of the convex part (22) in the width direction (X direction) and extends in the height direction (Z direction) of the convex part (22).

[0454] In this regard, in the grid structure (20) related to the second embodiment, as shown in FIGS. 18 and 19, at least the upper side of the convex portion (22) (at least the portion of the convex portion (22) covered with a reflective film (30)) is inclined in the width direction (X direction) of the convex portion (22) at a predetermined angle of inclination (α) with respect to the normal direction (Z direction) of the substrate (10). In short, the central axis (25) of the inclined portion of the convex portion (22) (an axis that passes through the center of the width direction of the inclined portion of the convex portion (22) and extends in the height direction of the inclined portion of the convex portion (22)) is inclined at an angle of inclination (α) with respect to the normal direction (Z direction) of the substrate (10) and is also inclined at (90° - α) with respect to the surface (XY plane) of the substrate (10). As a result, the reflective film (30) covering the upper side of the convex portion (22) is also inclined at an angle of inclination (α) with respect to the normal direction (Z direction) of the substrate (10).

[0455] In this way, the grid structure (20) related to the second embodiment has a grid inclination structure in which at least the upper side of the convex jaw (22) is inclined. By this grid inclination structure, the polarizing element (1) can be given directionality for incident oblique light (31) (e.g., θ = -45°) incident from the inclination direction of the side of the convex jaw (22) that is inclined (right side in the X direction of FIG. 18 and FIG. 19). In short, by the above grid inclination structure, the reflective film (30) covering the upper side of the inclined convex jaw (22) can be directed toward the incident oblique light (31) incident from the said inclination direction. Thus, the P polarization of the incident light (31) can easily pass through the gaps of the reflective films (30) of the adjacent convex portions (22), thereby improving the transmittance Tp of the P polarization, and at the same time, the reflectance Rs of the incident light (31) can be maintained at a high value without lowering it. Therefore, the polarization element (1) can be given a directivity that increases the transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) for the incident light (31) incident from the oblique direction.

[0456] For example, in the example of FIG. 18 and FIG. 19, the convex portion (22) of the grid structure (20) is inclined to the right in the X direction with respect to the normal direction (Z direction). As a result, the polarizing element (1) has excellent transmittance and polarization separation characteristics, particularly for incident light (31) (e.g., θ = -45°) incident from the direction inclined to the right among incident light. On the other hand, although not illustrated, when the convex portion (22) of the grid structure (20) is inclined to the left in the X direction with respect to the normal direction (Z direction), the polarizing element (1) has excellent transmittance and polarization separation characteristics, particularly for incident light (32) (e.g., θ = +45°) incident from the direction inclined to the left.

[0457] As described above, by the grid slope structure related to the second embodiment, a polarizing element (1) can be imparted with a directionality that further enhances the transmittance (transmittance Tp) and polarization separation characteristics (Tp × Rs characteristics) for incident oblique rays (31, 32) incident from a specific slope direction. Accordingly, a polarizing element (1) with superior transmittance (transmittance Tp) and polarization separation characteristics (Tp × Rs characteristics) for incident oblique rays (31, 32) incident from the said specific slope direction can be provided.

[0458] <7.1. Example of Grid Slope Structure Configuration>

[0459] Next, with reference to FIGS. 18 and 19, an example of the configuration of a grid slope structure related to the second embodiment will be described.

[0460] When applying a grid slope structure related to the second embodiment to a special tree-shaped grid (a structure combining a grid structure (20) and a reflective film (30)) related to the first embodiment described above, as shown in FIG. 18, only the upper part (22c) of the convex jaw (22) may be partially curved and sloped, forming a curved grid slope structure. Alternatively, as shown in FIG. 19, the entire convex jaw (22) may be sloped, forming a grid slope structure.

[0461] More specifically, in the grid slope structure shown in FIG. 18, the convex portion (22) is bent to the right in the width direction (X direction) of the convex portion (22) at a midpoint (27) in the height direction (Z direction) of the convex portion (22). Because of this, the upper part (22c) (the part above the bending position (27)) of the convex portion (22) is inclined at an angle of inclination (α) with respect to the normal direction (Z direction) of the surface of the substrate (10) and extends obliquely upward along this inclination direction. Meanwhile, the lower part (22d) of the convex portion (22) (the part below the bending position (27)) is not inclined with respect to the normal direction (Z direction) and extends straight upward along the Z direction.

[0462] For this reason, the central axis (25) of the upper part (22c) (sloping part) of the convex part (22) is bent to the right in the X direction at an angle of inclination (α) with respect to the central axis (26) of the lower part (22d) (non-sloping part) of the convex part (22). Additionally, the central axis (25) is an axis that passes through the center in the width direction of the sloping upper part (22c) of the convex part (22) and extends in the height direction of the said upper part (22c). The central axis (26) is an axis that passes through the center in the width direction (X direction) of the non-sloping lower part (22d) of the convex part (22) and extends in the height direction (Z direction) of the said lower part (22d).

[0463] Also, all or part of the upper portion (22c) of the convex jaw (22) is covered by a reflective film (30). As described above, since the upper portion (22c) of the convex jaw (22) is inclined at an angle of inclination (α), the reflective film (30) covering the upper portion (22c) (inclined portion) of the convex jaw (22) is also inclined at an angle of inclination (α) to the right in the X direction. Meanwhile, the lower portion (22d) of the convex jaw (22) is not covered by the reflective film (30).

[0464] As described above, in the grid slope structure shown in FIG. 18, the convex jaw (22) is bent in the X direction while in the Z direction, so that only the upper part (22c) of the convex jaw (22) is partially sloped. As a result, oblique incident light can preferably be incident on the lower side opening (resin part not covered by the reflective film (30)) of the side (22b) of the convex jaw (22) of the grid structure (20). Therefore, the curved grid slope structure shown in FIG. 18 has superior transmittance of oblique incident light and polarization separation characteristics compared to the overall grid slope structure shown in FIG. 19. In addition, the curved grid slope structure shown in FIG. 18 can extend the preferred range of the slope angle (α) compared to the overall grid slope structure shown in FIG. 19.

[0465] Also, in the grid slope structure shown in FIG. 19, the entire convex portion (22) is sloped in the width direction (X direction) of the convex portion (22) at an angle of inclination (α) with respect to the normal direction (Z direction) of the substrate (10). That is, the entire convex portion (22) is sloped from the source of the convex portion (22) that is joined to the base portion (21) and extends along this slope direction.

[0466] For this reason, the entire central axis (25) of the convex portion (22) is inclined at an angle of inclination (α) to the right in the X direction with respect to the normal direction (Z direction) of the substrate (10). As a result, the reflective film (30) covering the upper side of the convex portion (22) is also inclined at an angle of inclination (α) to the right in the X direction. Additionally, the central axis (25) shown in FIG. 19 is an axis that passes through the center in the width direction of the inclined convex portion (22) and extends in the height direction of the inclined convex portion (22).

[0467] As such, in the grid slope structure shown in FIG. 19, the entire convex portion (22) is sloped. The grid slope structure in which the entire convex portion (22) shown in FIG. 19 is sloped has a relatively simple shape compared to the curved grid slope structure shown in FIG. 18 described above. Therefore, when the grid structure (20) is formed using a transfer technique such as an imprint, the release properties are improved, so the grid slope structure can be formed relatively easily and with high precision.

[0468] <7.2. Desirable Range of Inclination Angle (α)>

[0469] Next, a preferred range of the inclination angle (α) of the convex portion (22) of the grid inclination structure related to the second embodiment will be described.

[0470] (1) 0°<α ≤ 15°

[0471] It is preferable that the inclination angle (α) of the convex shaping part (22) be greater than 0° and less than or equal to 15°. If the inclination angle (α) of the convex shaping part (22) is greater than 15°, the inclination of the convex shaping part (22) is excessively large, so there is a possibility that the transmittance Tp will decrease compared to when the convex shaping part (22) is not inclined. In contrast, if the inclination angle (α) of the convex shaping part (22) is less than or equal to 15°, the convex shaping part (22) can be inclined to an appropriate inclination angle (α) to match the incident light incident from the side where the convex shaping part (22) is inclined. Therefore, the transmittance Tp can be increased compared to when the convex shaping part (22) is not inclined, and the polarization separation characteristic (Tp × Rs characteristic) can be improved.

[0472] For example, in the grid inclination structure shown in FIG. 18, when incident light (31) is incident from the side where the convex portion (22) is inclined at an incident angle θ = -45°, if the inclination angle (α) is greater than 0° and less than or equal to 15°, the grid structure (20) can be given directionality suitable for said incident light (31). Thus, while maintaining the reflectance Rs at a high value of, for example, 90% or more, the transmittance Tp can be increased to, for example, 84% or more, so that Tp × Rs can be increased to a reference value or higher (for example, 76% or more).

[0473] In addition, the reference value is a reference value of Tp × Rs measured using a grid structure (20) that does not tilt the convex jaw (22) related to the first embodiment, and is, for example, 76%. If the value of Tp × Rs can be increased above the reference value by adopting a grid tilt structure related to the second embodiment, it can be said that there is an effect of increasing the polarization separation characteristic (Tp × Rs) for oblique incident light incident from a specific tilt direction.

[0474] In addition, in the grid inclination structure shown in FIG. 19, when incident light (31) is incident from the side where the convex part (22) is inclined at an incident angle θ = -45°, if the inclination angle (α) is greater than 0° and less than or equal to 10°, directionality suitable for said incident light can be imparted to the grid structure (20). Thus, while maintaining the reflectance Rs at a high value of, for example, 90% or more, the transmittance Tp can be increased to, for example, 84% or more, so that Tp × Rs can be increased to a reference value or higher (for example, 76% or more).

[0475] (2) 5° ≤ α ≤ 10°

[0476] In addition, it is more preferable that the inclination angle (α) of the convex jaw (22) be 5° or more and 10° or less. By doing so, the convex jaw (22) can be tilted to a more appropriate inclination angle (α) to match the incident light (31) incident from the side on which the convex jaw (22) is tilted. Accordingly, the transmittance Tp can be further increased and the polarization separation characteristic (Tp × Rs characteristic) can be further improved.

[0477] For example, in the grid inclination structure shown in FIG. 18, when incident light (31) (θ = -45°) incident from the side of the convex portion (22) is inclined, if the inclination angle (α) is 5° or more and 10° or less, the grid structure (20) can be given a directionality more suitable for said incident light. Thus, by maintaining Rs at a high value of, for example, 90% or more, Tp can be further increased to, for example, 85.8% or more, and thus Tp × Rs can be further increased to, for example, 77.3% or more.

[0478] In addition, in the grid inclination structure shown in FIG. 19, when the incident oblique light (31) (θ = -45°) is incident, if the inclination angle (α) is 5° or more and 10° or less, the grid structure (20) can be given a directionality more suitable for the incident oblique light (31). Thus, by maintaining Rs at a high value of, for example, 90% or more, Tp can be further increased to, for example, 84.5% or more, and thus Tp × Rs can be further increased to, for example, 76.7% or more.

[0479] <7.3. Desirable Range of Coverage Rate (Rc)>

[0480] Next, regarding the grid slope structure related to the second embodiment, a preferred range of coverage rate (Rc) when covering the side (22b) of the convex portion (22) by the reflective film (30) will be described.

[0481] <7.3.1. Coverage Rate (Rc) on Both Sides>

[0482] As shown in FIGS. 18 and 19, in a grid structure (20) having a grid slope structure related to the second embodiment, a reflective film (30) (functional film) covers the upper side of the leading edge (22a) and both sides (22b1, 22b2) (hereinafter collectively referred to as "sides (22b)") of the sloped convex portion (22). And, it is preferable that the coverage rate (Rc) (hereinafter referred to as "coverage rate Rc1, Rc2") of both sides (22b1, 22b2) of the convex portion (22) by the reflective film (30) is 30% or more and 70% or less.

[0483] In this way, the reflective film (30) covers both sides (22b1, 22b2) of the inclined convex jaw (22), and the coverage rate (Rc1, Rc2) is 30% or more and 70% or less, so that the grid inclined structure having the inclined convex jaw (22) can respond to both "incident light in the - direction (31)" and "incident light in the + direction (32)". Therefore, regardless of which direction the incident light is incident, it is possible to achieve good transmittance (transmittance Tp) and polarization separation characteristics (Tp × Rs characteristics).

[0484] In addition, in this specification, "oblique incident light in the - direction" refers to oblique incident light incident from the side where the convex part (22) is inclined with respect to the surface (XY plane) of the polarizing element (1). The incident angle θ of the "oblique incident light in the - direction (31)" is a negative value less than 0° (θ < 0°). In short, when the incident angle θ is a negative value (e.g., θ = -45°), it means that the oblique incident light is incident obliquely from the direction where the convex part (22) is inclined (positive direction of the X-axis) toward the negative direction of the X-axis.

[0485] Meanwhile, "oblique incident light in the + direction" is oblique incident light incident from the side opposite to the side on which the convex jaw (22) is inclined. The incident angle θ of the "oblique incident light in the + direction" is a positive value greater than 0° (θ > 0°). In short, when the incident angle θ is a positive value (e.g., θ = +45°), it means that the oblique incident light is incident obliquely from the direction opposite to the side on which the convex jaw (22) is inclined (negative direction of the X-axis) toward the direction on which the convex jaw (22) is inclined (positive direction of the X-axis).

[0486] For example, in the grid slope structure shown in FIGS. 18 and 19, the convex portion (22) is inclined to the right of the X direction (positive direction of the X-axis) with respect to the Z direction. Because of this, the "oblique incident light in the - direction" is oblique incident light (31) incident from the right of the X direction (positive direction of the X-axis) toward the left of the X direction (negative direction of the X-axis) at a negative incident angle θ (e.g., θ = -45°). Also, the "oblique incident light in the + direction" is oblique incident light (32) incident from the left of the X direction (negative direction of the X-axis) toward the right of the X direction (positive direction of the X-axis) at a positive incident angle θ (e.g., θ = +45°).

[0487] In addition, the range of the incident angle θ of the incident light varies depending on the specifications or use of the polarizing element (1), for example, it is a range of a predetermined angle width (e.g., ±15°, ±10°) centered on the central incident light from an inclination of 45°. More specifically, when the incident angle of the central incident light is 45° and the angle width is ±15°, the range of the incident angle θ of the incident light is, for example, +45° ±15° (i.e., +30° to 60°) and -45° ±15° (i.e., -60° to -30°). In addition, the incident angle of the central incident light may be various angles such as 30°, 55°, etc., in addition to the example of 45° above. In addition, the specified angle width may be various angle widths, such as ±5°, ±20°, ±25°, etc., in addition to the examples of ±15° and ±10° mentioned above.

[0488] <7.3.2. First and Second Sides of the Convex Grave>

[0489] The first side of the convex portion (22) is the side of the convex portion (22) that is inclined among the two sides (22b, 22b) of the convex portion (22). Meanwhile, the second side of the convex portion (22) is the side of the convex portion (22) that is opposite to the side of the convex portion (22) that is inclined among the two sides (22b, 22b) of the convex portion (22).

[0490] In the example of FIG. 18, since the upper part (22c) of the convex portion (22) is inclined to the right in the X direction, among the two sides (22b, 22b) of the upper part (22c) of the convex portion (22), the right side (22b1) of the upper part (22c) of the convex portion (22) is the first side, and the left side (22b2) of the upper part (22c) of the convex portion (22) is the second side. Also, in the example of FIG. 19, since the entire convex portion (22) is inclined to the right in the X direction, among the two sides (22b, 22b) of the entire convex portion (22), the right side (22b1) of the convex portion (22) is the first side, and the left side (22b2) of the convex portion (22) is the second side.

[0491] The coverage rate (Rc1) of the first side (22b1) of the convex portion (22) is represented by the following formula (11).

[0492] Rc1 [%] = (Hx1 / H) × 100... (11)

[0493] H: Height in the Z direction of the convex portion (22) [nm]

[0494] Hx1: Height in the Z direction of the portion covered by the reflective film (30) on the first side (22b1) of the convex portion (22) [nm]

[0495] Likewise, the coverage rate (Rc2) of the second side (22b2) of the convex portion (22) is represented by the following equation (12).

[0496] Rc2 [%] = (Hx2 / H) × 100... (12)

[0497] H: Height in the Z direction of the convex portion (22) [nm]

[0498] Hx2: Height in the Z direction of the portion covered by the reflective film (30) on the second side (22b2) of the convex portion (22) [nm]

[0499] <7.3.3. Coverage Rate of the First Side of the Convex Grain (Rc1)>

[0500] (1) - Obliquely incident light in the - direction (35 % ≤ Rc1 ≤ 50 %)

[0501] With respect to the surface of the polarizing element (1), when incident light (31) is incident from the side of the convex portion (22) that is inclined (in other words, when incident light in the - direction is incident at a negative incident angle θ), the coverage rate (Rc1) of the first side (22b1) of the convex portion (22) is preferably 35% or more and 50% or less.

[0502] Thus, when "oblique incident light in the - direction" is incident, the coverage rate (Rc1) of the first side (22b1) can be adjusted to an appropriate range by matching a negative incident angle θ (e.g., θ = -45°). Therefore, while maintaining the reflectance Rs at a high value of, for example, 90% or more, the transmittance Tp can be increased to, for example, 84% or more, so Tp × Rs can be increased to a reference value or higher (e.g., 76% or more) (see FIG. 23).

[0503] (2) + direction oblique incidence light (40 % ≤ Rc1 ≤ 53 %)

[0504] With respect to the surface of the polarizing element (1), when incident light (32) is incident from the side opposite to the side on which the convex portion (22) is inclined (in other words, when "incident light in the + direction" is incident at a positive incident angle θ), the coverage rate (Rc1) of the first side (22b1) of the convex portion (22) is preferably 40% or more and 53% or less.

[0505] Thus, when "obliquely incident light in the + direction" is incident, the coverage rate (Rc1) of the first side (22b1) can be adjusted to an appropriate range in accordance with the positive incident angle θ (e.g., θ = +45°). Therefore, since the reflectance Rs can be maintained at a high value of, for example, 90% or more, and the transmittance Tp can be increased to, for example, 84% or more, Tp × Rs can be increased to a reference value or higher (e.g., 76% or more) (see FIG. 23).

[0506] <7.3.4. Coverage Rate of the Second Side of the Convex Grain (Rc2)>

[0507] (1) - Obliquely incident light in the - direction (35 % ≤ Rc2 ≤ 55 %)

[0508] With respect to the surface of the polarizing element (1), when incident light (31) is incident from the side of the convex portion (22) that is inclined (in other words, when incident light in the - direction is incident at a negative incident angle θ), the coverage rate (Rc2) of the second side (22b2) of the convex portion (22) is preferably 35% or more and 55% or less.

[0509] Thus, when "oblique incident light in the - direction" is incident, the coverage rate (Rc2) of the second side (22b2) can be adjusted to an appropriate range by matching a negative incident angle θ (e.g., θ = -45°). Therefore, since the reflectance Rs can be maintained at a high value of, for example, 90% or more, and the transmittance Tp can be increased to, for example, 84% or more, Tp × Rs can be increased to a reference value or higher (e.g., 76% or more) (see FIG. 24).

[0510] (2) + direction oblique incidence light (35 % ≤ Rc2 ≤ 45 %)

[0511] With respect to the surface of the polarizing element (1), when incident light (32) is incident from the side opposite to the side on which the convex portion (22) is inclined (in other words, when "incident light in the + direction" is incident with a positive incident angle θ), the coverage rate (Rc2) of the second side (22b2) of the convex portion (22) is preferably 35% or more and 45% or less.

[0512] Thus, when "obliquely incident light in the + direction" is incident, the coverage rate (Rc2) of the second side (22b2) can be adjusted to an appropriate range in accordance with the positive incident angle θ (e.g., θ = +45°). Therefore, since the reflectance Rs can be maintained at a high value of, for example, 90% or more, and the transmittance Tp can be increased to, for example, 84% or more, Tp × Rs can be increased to a reference value or higher (e.g., 76% or more) (see FIG. 24).

[0513] Examples

[0514] Next, embodiments of the present invention will be described. However, the embodiments described below are specific examples provided to explain the configuration or effects of the polarizing element (1) related to the embodiments described above, and the present invention is not limited to the following embodiments.

[0515] <1. Verification Results of Grid Slope Structure>

[0516] As an embodiment of the present invention, a model of a wire grid polarizing element (1) having a grid tilt structure related to the second embodiment described above was fabricated, and by simulating various characteristics thereof, the wire grid polarizing element (1) (tilt angle α > 0°) related to the embodiment was evaluated. In addition, to compare with the wire grid polarizing element (1) (tilt angle α > 0°) having a grid tilt structure related to the embodiment of the present invention, a model of a wire grid polarizing element (1) (tilt angle α = 0°) related to a comparative example not having the said grid tilt structure was also fabricated and simulated and evaluated in the same way. Furthermore, for convenience of explanation, in the following, the same reference numerals and symbols are used for the reference numerals indicating the components of the polarizing element (1) (substrate (10), grid structure (20), base part (21), convex part (22), reflective film (30), etc.) and for the symbols indicating various dimensions of these components.

[0517] In addition, the symbols representing various dimensions of the polarizing element (1) used in the following description are explained as follows.

[0518] P: Pitch of the convex part (22)

[0519] W T : The width of the government of the convex grandfather (22) (convex grandfather government width)

[0520] W M : Width of the central position in the height direction of the convex part (22) (central width of the convex part)

[0521] W B : Width of the bottom of the convex part (22) (grid bottom width)

[0522] W MAX : Maximum width of the reflective film (30) covering the convex portion (22) (maximum grid width)

[0523] H: Height of the convex protrusion (22)

[0524] Hx: Height of the portion covered by the reflective film (30) on the side (22b) of the convex portion (22).

[0525] Hx1: Height of the portion covered by the reflective film (30) on the first side (22b1) of the convex protrusion (22).

[0526] Hx2: Height of the portion covered by the reflective film (30) on the second side (22b2) of the convex portion (22).

[0527] Dt: Thickness of the reflective film (30) covering the tip (22a) of the convex portion (22) (tip thickness of the reflective film (30))

[0528] Ds: Thickness of the reflective film (30) covering the side (22b) of the convex portion (22) (side thickness of the reflective film (30))

[0529] Rc: Coverage rate of the side (22b) of the convex portion (22) by the reflective film (30)

[0530] Rc1: Coverage rate of the first side (22b1) of the convex portion (22) by the reflective film (30).

[0531] Rc2: Coverage rate of the second side (22b2) of the convex portion (22) by the reflective film (30).

[0532] Rr: Opening rate of the side (22b) of the convex portion (22) by the reflective film (30)

[0533] Rr1: Opening rate of the first side (22b1) of the convex portion (22) by the reflective film (30)

[0534] Rr2: Opening rate of the second side (22b2) of the convex portion (22) by the reflective film (30)

[0535] θ: Angle of incidence of incident light

[0536] λ: Wavelength of incident light

[0537] α: Angle of inclination of the convex portion (22)

[0538] (Example 40)

[0539] First, with reference to FIGS. 20 and FIGS. 21, an embodiment 40 of the present invention will be described.

[0540] As shown in FIG. 20, a model of a polarizing element (1) related to Example 40 was fabricated. The polarizing element (1) related to Example 40 comprises a glass substrate (10) and a grid structure (20) made of a UV-curable resin (acrylic resin). The grid structure (20) has a base portion (21) formed along the surface of the substrate (10) and a plurality of convex portions (22) protruding in a grid pattern from the base portion (21). The cross-sectional shape of the convex portions (22) is a vertically elongated trapezoid, and is a shape that tapers toward the tip (22a) of the convex portion (22).

[0541] The reflective film (30) covering the convex portion (22) of Example 40 is an Al film. The reflective film (30) is formed to cover the tip (22a) of the convex portion (22) and the upper side of both sides (22b1, 22b2). However, the reflective film (30) does not cover the lower side of both sides (22b1, 22b2) of the convex portion (22) and the base portion (21). The coverage rate (Rc1, Rc2) of both sides (22b1, 22b2) of the convex portion (22) by the reflective film (30) is 45%. In this way, the reflective film (30) of Example 40 covers the top of the convex portion (22) (the upper side of the tip (22a) and the two sides (22b1, 22b2)) in a rounded manner. The surface of the reflective film (30) is approximately elliptical in shape with a rounded shape that bulges outward, and is bulged outward in the width direction of the convex portion (22).

[0542] As a result, the grid related to Example 40 (a structure combining the convex portion (22) and the reflective film (30)) has the special tree shape described above. The maximum width (W) of the grid of the special tree shape said is MAX ) (the width of the grid at the most bulging part of the reflective film (30)) is the width (W) of the bottom of the convex part (22). B ) (Width of the convex part (22) at a height position 20% above the bottom of the convex part (22)) or more.

[0543] In Example 40, to form a grid slope structure, the upper part (22c) of the convex jaw (22) was sloped at an angle of inclination (α) on one side in the width direction of the convex jaw (22) (right side of FIG. 20(a)). The sloped upper part (22c) was set to be the upper 50% portion in the height direction of the convex jaw (22). The angle of inclination (α) in Example 40 was set to 5°, 10°, and 15°.

[0544] Meanwhile, in the model of the polarizing element (1) related to Comparative Example 40, the convex portion (22) is not tilted and a grid tilt structure is not formed. That is, in Comparative Example 40, the tilt angle α = 0° and the convex portion (22) is extended straight upward in the normal direction (Z direction) of the surface of the substrate (10).

[0545] In addition, as Comparative Example 41, a model was also created in which the upper part (22c) of the convex jaw (22) is inclined at a large inclination angle (α) of 15° or more on one side (right side of FIG. 20(a)) in the width direction of the convex jaw (22). The inclination angle (α) of Comparative Example 41 was set to 20°, 25°, 30°, 40°, and 45°.

[0546] The dimensions and shapes of each part of the model of the polarizing element (1) related to Example 40 and Comparative Examples 40 and 41 are as follows.

[0547] P : 142 nm

[0548] W T : 17 nm

[0549] W B : 65 nm

[0550] W MAX : 65 nm

[0551] H : 225 nm

[0552] Hx = Hx1 = Hx2 : 101 nm

[0553] Dt : 38 nm

[0554] Ds : 17.5 nm (maximum value)

[0555] Rc = Rc1 = Rc2 : 45 %

[0556] Rr = Rr1 = Rr2 : 55 %

[0557] θ : -45°, +45°

[0558] λ : 430 ∼ 680 nm

[0559] α : 5°, 10°, 15° (Example 40)

[0560] α : 0° (Comparative Example 40)

[0561] α : 20°, 25°, 30°, 35°, 40°, 45° (Comparative Example 41)

[0562] Simulations were performed on the models of polarizing elements (1) related to Example 40 and Comparative Examples 40 and 41 manufactured as described above, and transmission axis transmittance (Tp), reflection axis transmittance (Ts), transmission axis reflectance (Rp), reflection axis reflectance (Rs), and Tp × Rs required as a polarizing beam splitter (PBS) were calculated, respectively. At this time, for Example 40 (α = 5° ~ 15°), Comparative Example 40 (α = 0°), and Comparative Example 41 (α = 20° ~ 45°), the values ​​of Tp, Ts, Rp, and Rs were calculated for each case where "oblique incident light in the - direction (θ = -45°)" was incident and when "oblique incident light in the + direction (θ = +45°)" was incident. In addition, for the values ​​of Tp, Ts, Rp, and Rs, the wavelength λ of the incident light was varied in the range of 430 to 680 nm, and the average value of multiple Tp, Ts, Rp, and Rs values ​​calculated for each incident light of wavelength λ was used.

[0563] The relationship between the Tp characteristic, Rs characteristic, Tp × Rs characteristic and the slope angle (α) related to Example 40 and Comparative Examples 40 and 41, obtained as described above, is shown in the graphs of FIGS. 20(b) to (d) and FIGS. 21(b) to (d). In addition, FIGS. 20(b) to (d) and FIGS. 21(b) to (d) show the same Tp characteristic, Rs characteristic, and Tp × Rs characteristic, although the scale of the slope angle (α) on the horizontal axis is different.

[0564] As shown in FIG. 20(a), in the model of the polarizing element (1) related to Example 40, the reflective film (30) covers the upper part of the convex jaw (22) and leaves the lower part of the convex jaw (22) open, and the coverage rate (Rc) is 45%. Because of this, the grid related to Example 40 (a structure combining the convex jaw (22) and the reflective film (30)) has the special tree shape described above. In addition, the grid related to Example 40 has a curved grid slope structure in which the upper part (22c) of the convex jaw (22) is bent to the right and sloped, and the slope angle (α) of the upper part (22c) of the convex jaw (22) is adjusted to an appropriate range of greater than 0° and less than or equal to 15°.

[0565] As shown in FIGS. 20 and 21, Example 40 (α = 5° to 15°) has an inclination angle (α) of the curved grid inclination structure within an appropriate range, so compared to Comparative Example 40 (α = 0°) or Comparative Example 41 (α = 20° to 45°), it has excellent transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) for incident light from a specific inclination direction (e.g., incident light in the - direction (θ = -45°) and incident light in the + direction (θ = +45°)).

[0566] In detail, first, when comparing the reflectance Rs, as shown in FIG. 20(c) and FIG. 21(c), in the range of inclination angle (α) from 0° to 45°, Rs maintains a high value of 90% or more regardless of the size of α. Therefore, it can be seen that when the convex portion (22) is inclined as in Example 40 (α = 5° to 15°), a high Rs of 90% or more can be secured, just as in Comparative Example 40 (α = 0°), where the convex portion (22) is not inclined, and thus excellent reflectivity (Rs characteristic) can be exhibited by the reflective film (30).

[0567] Next, when comparing the transmittance Tp, as shown in FIG. 20(b), the Tp of the reference comparative example 40 (α = 0°) is approximately 84%. Also, as shown in FIG. 21(b), in comparative example 41 (α = 20° to 45°), Tp is 82% or less, which is lower than that of the reference comparative example 40 (α = 0°). Furthermore, in comparative example 41, as α increases in the range of 20° or more, Tp decreases, and in the case of α = 45°, Tp decreases to 60% or less. Therefore, in the case of the curved grid slope structure shown in FIG. 20(a), when α is 20° or more as in Comparative Example 41, it can be seen that Tp becomes small because the slope angle (α) of the convex part (22) is excessively large, which is undesirable.

[0568] In this regard, the Tp of Example 40 (α = 5° to 15°) is 84.3% or higher, and is higher than that of the standard Comparative Example 40 (α = 0°) for both obliquely incident light in the + direction (θ = +45°) and obliquely incident light in the - direction (θ = -45°). In particular, in the case of α = 5° and 10° of Example 40, it has excellent directivity for obliquely incident light in the - direction (θ = -45°), and the Tp is 85.8% or higher, which is significantly higher compared to Comparative Example 40 (α = 0°).

[0569] Accordingly, as in Example 40, it can be seen that if α is in an appropriate range greater than 0° and less than or equal to 15°, the transmittance (Tp characteristic) for obliquely incident light from a specific oblique direction (θ = -45°, +45°) can be improved. In particular, if α is in a desirable range greater than or equal to 5° and less than or equal to 10°, it can be seen that it has very excellent transmittance (Tp characteristic) for obliquely incident light in the - direction (θ = -45°).

[0570] Next, we compare Tp × Rs, which is the product of the above Rs and Tp. As shown in FIG. 20(d), the Tp × Rs of the reference comparative example 40 (α = 0°) is approximately 76%. Also, as shown in FIG. 21(d), in comparative example 41 (α = 20° to 45°), Tp × Rs is 75% or less, which is lower than that of the reference comparative example 40 (α = 0°). Furthermore, in comparative example 41, as α increases in the range of 20° or more, Tp × Rs decreases, and in the case of α = 45°, Tp × Rs decreases to 55% or less. Therefore, in the case of the curved grid slope structure shown in FIG. 20(a), as in Comparative Example 41, if α is 20° or more, it can be seen that Tp × Rs becomes small because α is excessively large, which is undesirable.

[0571] In this regard, the Tp × Rs of Example 40 (α = 5° to 15°) is 76.2% or higher, and is higher than that of the standard Comparative Example 40 for both obliquely incident light in the + direction (θ = +45°) and obliquely incident light in the - direction (θ = -45°). In particular, in the case of α = 5° and 10° of Example 40, it has excellent directivity for obliquely incident light in the - direction (θ = -45°), and the Tp × Rs is 77.3% or higher, which is significantly higher compared to Comparative Example 40 (α = 0°).

[0572] Accordingly, in the case of the curved grid tilt structure shown in FIG. 20(a), as in Example 40, if α is in an appropriate range greater than 0° and less than or equal to 15°, it can be seen that the polarization separation characteristics (Tp × Rs characteristics) for obliquely incident light from a specific tilt direction (θ = -45°, +45°) can be improved. In particular, if α is in a desirable range greater than 5° and less than or equal to 10°, it can be seen that it has very excellent polarization separation characteristics (Tp × Rs characteristics) for obliquely incident light in the - direction (θ = -45°).

[0573] As such, regarding the Tp × Rs characteristics required for a polarizing beam splitter (PBS), Example 40 is superior to Comparative Examples 40 and 41, and in particular, when the tilt angle (α) is 5° to 10°, Tp × Rs characteristics with directional properties for oblique incident light in the - direction (θ = -45°) are obtained. For this reason, when the polarizing element (1) related to Example 40 is used as a polarizing beam splitter, it can be seen that the transmittance of P polarization (transmittance Tp) and polarization separation characteristics (Tp × Rs characteristics) are significantly superior for oblique incident light incident from a specific direction. Therefore, it can be said that the polarization separation characteristics required for a polarizing beam splitter can be sufficiently satisfied for oblique incident light incident from the said specific direction. Therefore, when an image is projected using the polarizing element (1) related to Example 40 as a polarizing beam splitter, the balance of brightness of the displayed image is good when viewed from an observer, and the image condition is also good.

[0574] As described above, in Example 40, in the curved grid slope structure shown in FIG. 20(a), the slope angle (α) of the convex portion (22) is adjusted to an appropriate angle greater than 0° and less than or equal to 15°. Thus, in Example 40, while maintaining Rs at a high value of 90% or more, Tp can be increased to more than 84%, and thus Tp × Rs can be increased to more than the reference value of 76%. Therefore, according to Example 40, it can be seen that superior transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) are obtained for both obliquely incident light in the + direction (θ = +45°) and obliquely incident light in the - direction (θ = -45°) compared to the reference Comparative Example 40.

[0575] In particular, regarding oblique incident light in the - direction (θ = -45°), it can be seen that by tilting the upper part (22c) of the convex part (22) at an angle of inclination (α) of 5° or more and 10° or less, the transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) can be greatly improved. Therefore, it can be said that a polarizing element (1) with excellent transmittance and polarization separation characteristics can be provided, which has directionality for oblique incident light in the - direction (θ = -45°).

[0576] (Example 42)

[0577] Next, with reference to FIG. 22, Example 42 of the present invention will be described.

[0578] As shown in FIG. 22, a model of the polarizing element (1) related to Example 42 was fabricated. In Example 42, a grid having a special tree shape (a structure combining the convex jaw (22) and the reflective film (30)) was fabricated, similar to Example 40 described above, except for the method of tilting the convex jaw (22).

[0579] In Example 42, in order to form a grid slope structure, the entire convex portion (22) was sloped at an angle of inclination (α) on one side (right side of FIG. 22(a)) in the width direction of the convex portion (22). The angle of inclination (α) in Example 42 was set to 5°, 10°, and 15°.

[0580] Meanwhile, in the model of the polarizing element (1) related to Comparative Example 42, the convex portion (22) is not tilted and a grid tilt structure is not formed. That is, in Comparative Example 42, the tilt angle α = 0° and the convex portion (22) is extended straight upward in the normal direction (Z direction) of the surface of the substrate (10).

[0581] In addition, as Comparative Example 43, a model was also created in which the entire convex portion (22) was inclined at a large inclination angle (α) of more than 10° on one side (right side of FIG. 22(a)) in the width direction of the convex portion (22). The inclination angle (α) of Comparative Example 43 was set to 15° and 30°.

[0582] The dimensions and shapes of each part of the model of the polarizing element (1) related to Example 42 and Comparative Examples 42 and 43 are as follows.

[0583] P : 142 nm

[0584] W T : 17 nm

[0585] W B : 65 nm

[0586] W MAX : 65 nm

[0587] H : 225 nm

[0588] Hx = Hx1 = Hx2 : 101 nm

[0589] Dt : 38 nm

[0590] Ds : 17.5 nm (maximum value)

[0591] Rc = Rc1 = Rc2 : 45 %

[0592] Rr = Rr1 = Rr2 : 55 %

[0593] θ : -45°, +45°

[0594] λ : 430 ∼ 680 nm

[0595] α : 0° (Comparative Example 42)

[0596] α : 5°, 10° (Example 42)

[0597] α : 15°, 30° (Comparative Example 43)

[0598] Simulations were performed on the models of polarizing elements (1) related to Example 42 and Comparative Examples 42 and 43 manufactured as described above, and Tp, Ts, Rp, Rs, and Tp × Rs were calculated, respectively. At this time, for Example 42 (α = 5° ~ 15°), Comparative Example 42 (α = 0°), and Comparative Example 43 (α = 30°), the values ​​of Tp, Ts, Rp, and Rs were calculated in the case where "oblique incident light in the - direction (θ = -45°)" was incident and in the case where "oblique incident light in the + direction (θ = +45°)" was incident, respectively. In addition, for the values ​​of Tp, Ts, Rp, and Rs, the wavelength λ of the incident light was varied in the range of 430 to 680 nm, and the average value of multiple Tp, Ts, Rp, and Rs values ​​calculated for each incident light of wavelength λ was used.

[0599] The relationship between the Tp characteristic, Rs characteristic, Tp × Rs characteristic and slope angle (α) related to Example 42 and Comparative Examples 42 and 43, obtained as described above, is shown in the graphs of FIGS. 22(b) to (d).

[0600] As shown in FIG. 22(a), in the model of the polarizing element (1) related to Example 42, the reflective film (30) covers the upper part of the convex jaw (22) and leaves the lower part of the convex jaw (22) open, and the coverage rate (Rc) is 45%. Because of this, the grid related to Example 42 (a structure combining the convex jaw (22) and the reflective film (30)) has the special tree shape described above. In addition, the grid related to Example 42 has an overall grid tilt structure in which the entire convex jaw (22) is tilted to the right, and the overall tilt angle (α) of the convex jaw (22) is adjusted to an appropriate range of greater than 0° and less than or equal to 15°.

[0601] As shown in FIG. 22, Example 42 (α = 5° to 10°) has an inclination angle (α) of the overall grid inclination structure within an appropriate range, so compared to Comparative Example 42 (α = 0°) and Comparative Example 43 (α = 30°), it has excellent transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) for incident light from a specific inclination direction (e.g., incident light in the - direction (θ = -45°) and incident light in the + direction (θ = +45°)).

[0602] In detail, first, when comparing the reflectance Rs, as shown in FIG. 22(c), in the range of inclination angle (α) from 0° to 30°, Rs maintains a high value of 90% or more regardless of the size of α. Therefore, it can be seen that when the convex portion (22) is inclined as in Example 42 (α = 5° to 15°), a high Rs of 90% or more can be secured, just as in Comparative Example 42 (α = 0°), where the convex portion (22) is not inclined, and excellent reflectivity (Rs characteristic) can be exhibited by the reflective film (30).

[0603] Next, when comparing the transmittance Tp, as shown in FIG. 22(b), the Tp of the reference comparative example 42 (α = 0°) is approximately 84%. In addition, in comparative example 43 (α = 15°, 30°), Tp is 83% or less, which is significantly lower than that of the reference comparative example 42 (α = 0°). Furthermore, in comparative example 43, as α increases in the range of 15° or more, Tp decreases. Therefore, in the case of the overall grid slope structure shown in FIG. 22(a), when α is 15° or more as in comparative example 43, it can be seen that Tp becomes small because the slope angle (α) of the convex part (22) is excessively large, which is undesirable.

[0604] In this regard, the Tp of Example 42 (α = 5°, 10°) is 84% ​​or higher, and for both obliquely incident light in the + direction (θ = +45°) and obliquely incident light in the - direction (θ = -45°), it is equivalent to or higher than the standard Comparative Example 42 (α = 0°). In particular, in the case of obliquely incident light in the - direction (θ = -45°), the Tp of Example 42 (α = 5°, 10°) is 84.5% or higher, which is significantly higher compared to Comparative Example 42 (α = 0°). In addition, in the case of α = 5° in Example 42, for both obliquely incident light in the + direction (θ = +45°) and obliquely incident light in the - direction (θ = -45°), Tp is 84.5% or higher, and is significantly higher compared to Comparative Example 42 (α = 0°).

[0605] Therefore, in the case of the overall grid tilt structure shown in FIG. 22(a), as in Example 42, if α is in an appropriate range greater than 0° and less than or equal to 10°, it can be seen that the transmittance (Tp characteristic) for incident oblique light from a specific tilt direction (θ = -45°, +45°) can be improved. In particular, it can be seen that it has very excellent transmittance (Tp characteristic) for incident oblique light in the - direction (θ = -45°).

[0606] Next, we compare Tp × Rs, which is the product of the above Rs and Tp. As shown in FIG. 22(d), the Tp × Rs of the reference Comparative Example 42 (α = 0°) is approximately 76%. In addition, in Comparative Example 43 (α = 15°, 30°), Tp × Rs is 75.2% or less, which is lower than that of the reference Comparative Example 42 (α = 0°). Therefore, in the case of the overall grid slope structure shown in FIG. 22(a), it can be seen that if α is 15° or more as in Comparative Example 43, α is excessively large, causing Tp × Rs to become smaller, which is undesirable.

[0607] In this regard, the Tp × Rs of Example 42 (α = 5°, 10°) is 76.2% or higher, and for both obliquely incident light in the + direction (θ = +45°) and obliquely incident light in the - direction (θ = -45°), it is equivalent to or better than the standard Comparative Example 42. In particular, it has excellent directivity for obliquely incident light in the - direction (θ = -45°), and the Tp × Rs is 76.7% or higher, which is significantly higher compared to Comparative Example 42 (α = 0°).

[0608] Accordingly, in the case of the overall grid tilt structure shown in FIG. 22(a), as in Example 42, if α is in an appropriate range greater than 0° and less than or equal to 10°, it can be seen that the polarization separation characteristics (Tp × Rs characteristics) for obliquely incident light from a specific tilt direction (θ = -45°, +45°) can be improved. In particular, if α is in a desirable range greater than 5° and less than or equal to 10°, it can be seen that it has very excellent polarization separation characteristics (Tp × Rs characteristics) for obliquely incident light in the - direction (θ = -45°).

[0609] As described above, in Example 42, in the overall grid inclination structure shown in FIG. 22(a), the inclination angle (α) of the convex portion (22) is adjusted to an appropriate angle greater than 0° and less than or equal to 10°. Thus, in Example 42, while maintaining Rs at a high value of 90% or more, Tp can be increased to 84% or more, thereby increasing Tp × Rs to a value greater than the reference value of 76%. Therefore, according to Example 42, it can be seen that superior transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) are obtained for both obliquely incident light in the + direction (θ = +45°) and obliquely incident light in the - direction (θ = -45°) compared to the reference Comparative Example 42.

[0610] In particular, regarding oblique incident light in the - direction (θ = -45°), it can be seen that by tilting the entire convex portion (22) at an angle of inclination (α) of 5° or more and 10° or less, the transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) can be greatly improved. Therefore, it can be said that a polarizing element (1) with excellent transmittance and polarization separation characteristics can be provided, which has directionality for oblique incident light in the - direction (θ = -45°).

[0611] (Example 43)

[0612] Next, with reference to FIG. 23, Example 43 of the present invention will be described.

[0613] As shown in FIG. 23, a model of the polarizing element (1) related to Example 43 was fabricated. In Example 43, a grid having a special tree shape (a structure combining the convex jaw (22) and the reflective film (30)) was fabricated, similar to Example 40 described above, except that the coverage rate (Rc1) of the first side (22b1) of the convex jaw (22) was changed. In Example 43, to form a grid slope structure, the upper part (22c) of the convex jaw (22) (the upper 50% portion of the convex jaw (22)) was sloped at an angle of inclination (α) toward one side in the width direction of the convex jaw (22) (the right side of FIG. 23(a)). The angle of inclination (α) in Example 43 was fixed at 10°.

[0614] Also, in Example 44, the coverage rate (Rc) of the reflective film (30) covering the convex portion (22) was varied between the first side (22b1) and the second side (22b2). The first side (22b1) is the side (22b) on the side where the convex portion (22) is inclined (the right side in FIG. 23(a)), and the second side (22b2) is the side (22b) on the opposite side of the convex portion (22) from the inclined side (the left side in FIG. 23(a)). In Example 43, the coverage rate (Rc2) (= Hx2 / H) of the second side (22b2) was fixed at 45%, and the coverage rate (Rc1) (= Hx1 / H) of the first side (22b1) was varied in the range of 35 to 55%.

[0615] The dimensions and shapes of each part of the model of the polarizing element (1) related to Example 43 are as follows.

[0616] P : 142 nm

[0617] W T : 17 nm

[0618] W B : 65 nm

[0619] W MAX : 65 nm

[0620] H : 225 nm

[0621] Hx1 : 79 nm, 90 nm, 101 nm, 113 nm, 124 nm (variable value)

[0622] Hx2 : 101 nm (fixed value)

[0623] Dt : 38 nm

[0624] Ds : 17.5 nm (maximum value)

[0625] Rc1 : 35 %, 40 %, 45 %, 50 %, 55 % (variable value)

[0626] Rr1 : 65 %, 60 %, 55 %, 50 %, 45 % (variable value)

[0627] Rc2 : 45 % (fixed value)

[0628] Rr2 : 55 % (fixed value)

[0629] θ : -45°, +45°

[0630] λ : 430 ∼ 680 nm

[0631] α : 10° (fixed value)

[0632] A simulation was performed on the model of the polarizing element (1) related to Example 43 fabricated as described above, and Tp, Ts, Rp, Rs, and Tp × Rs were calculated, respectively. At this time, the values ​​of Tp, Ts, Rp, and Rs were calculated for the case where "oblique incident light in the - direction (θ = -45°)" was incident and for the case where "oblique incident light in the + direction (θ = +45°)" was incident. In addition, for the values ​​of Tp, Ts, Rp, and Rs, the wavelength λ of the oblique incident light was varied in the range of 430 to 680 nm, and the average value of the multiple values ​​of Tp, Ts, Rp, and Rs calculated for each wavelength λ was used. In addition, the contrast (CR) of the transmitted light was also calculated by dividing Tp by Ts (CR = Tp / Ts).

[0633] The relationship between the Tp characteristic, Rs characteristic, Tp × Rs characteristic, contrast CR related to Example 43 obtained as described above, and the coverage rate (Rc1) of the first side (22b1) is shown in the graphs of FIGS. 23(b) to (e).

[0634] As shown in FIG. 23(c), the reflectance Rs of Example 43 maintains a high value of 90% or more regardless of the magnitude (35 to 55%) of the coverage rate (Rc1) in both cases of "oblique incident light in the - direction (θ = -45°)" and "oblique incident light in the + direction (θ = +45°)". Therefore, it can be seen that a high Rs of 90% or more can be secured regardless of Rc1, and excellent reflectivity (Rs characteristic) can be exhibited by the reflective film (30).

[0635] Meanwhile, as shown in FIGS. 23(b) and FIGS. 23(d), regarding the Tp characteristics and Tp × Rs characteristics, the behavior of the Tp characteristics and Tp × Rs characteristics according to the coverage rate (Rc1) differs depending on whether the incident direction of the obliquely incident light is the "- direction (θ = -45°)" or the "+ direction (θ = +45°)". Below, the reference values ​​of Tp (84%) and Tp × Rs (76%) of Comparative Example 40 (α = 0°) shown in FIG. 20 described above are compared with the Tp and Tp × Rs of Example 43 (α = 10°) shown in FIG. 23, and the Tp characteristics and Tp × Rs characteristics of Example 43 are evaluated.

[0636] (1) - Obliquely incident light in the - direction (35 % ≤ Rc1 ≤ 50 %)

[0637] First, when the incident direction is the "- direction (θ = -45°)", in Example 43, if Rc1 is in the range of 35% or more and 50% or less, Tp becomes equal to or greater than the reference value (84%) as shown in FIG. 23(b), and as a result, Tp × Rs also becomes equal to or greater than the reference value (76%) as shown in FIG. 23(d). Therefore, in the case of "oblique incident light in the - direction (θ = -45°)", it can be seen that good transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) are obtained by adjusting Rc1 to the range of 35% or more and 50% or less.

[0638] In addition, it is desirable to adjust Rc1 to a range of 40% or more and 45% or less. As a result, as shown in FIG. 23(b), Tp becomes 85.8% or more, and as shown in FIG. 23(d), Tp × Rs becomes 77% or more. Therefore, it can be seen that better transmittance (Tp characteristics) and polarization separation characteristics (Tp × Rs characteristics) are obtained.

[0639] (2) + direction oblique incidence light (40 % ≤ Rc1 ≤ 53 %)

[0640] Meanwhile, when the incident direction is the "+ direction (θ = +45°)", in Example 43, if Rc1 is in the range of 40% or more and 53% or less, Tp becomes equal to or greater than the reference value (84%) as shown in FIG. 23(b), and as a result, Tp × Rs also becomes equal to or greater than the reference value (76%) as shown in FIG. 23(d). Therefore, it can be seen that in the case of "obliquely incident light in the + direction (θ = +45°)", good transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) are obtained by adjusting Rc1 to the range of 40% or more and 53% or less.

[0641] In addition, it is desirable to adjust Rc1 to a range of 45% or more and 50% or less. As a result, as shown in FIG. 23(b), Tp becomes 85% or more, and as shown in FIG. 23(d), Tp × Rs becomes 76.5% or more. Therefore, it can be seen that better transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) are obtained.

[0642] Also, regarding the contrast CR, as shown in FIG. 23(e), it can be seen that in both cases of "obliquely incident light in the - direction (θ = -45°)" and "obliquely incident light in the + direction (θ = +45°)", the greater the coverage rate (Rc1), the higher the contrast CR becomes.

[0643] From the results of Example 43 above, it can be seen that even if the coverage rate (Rc1) is non-uniform when manufacturing the grid, by tilting the convex portion (22), transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) equivalent to or greater than that of the standard (Comparative Example 40) can be obtained. Therefore, it can be said that by changing the installation direction of the grid tilt structure of the polarizing element (1) according to the incident direction (+ direction or - direction) of the incident oblique light, a polarizing element (1) with excellent transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) for directional oblique light can be provided.

[0644] (Example 44)

[0645] Next, with reference to FIG. 24, Example 44 of the present invention will be described.

[0646] As shown in FIG. 24, a model of the polarizing element (1) related to Example 44 was fabricated. In Example 44, a grid having a special tree shape (a structure combining the convex jaw (22) and the reflective film (30)) was fabricated, similar to Example 40 described above, except that the coverage ratio (Rc2) of the second side (22b2) of the convex jaw (22) was changed. In Example 44, to form a grid slope structure, the upper part (22c) of the convex jaw (22) (the upper 50% portion of the convex jaw (22)) was sloped at an angle of inclination (α) toward one side in the width direction of the convex jaw (22) (the right side of FIG. 24(a)). The angle of inclination (α) in Example 44 was fixed at 10°.

[0647] Also, in Example 44, the coverage rate (Rc) of the reflective film (30) covering the convex portion (22) was varied between the first side (22b1) and the second side (22b2). The first side (22b1) is the side (22b) on the side where the convex portion (22) is inclined (the right side in FIG. 24(a)), and the second side (22b2) is the side (22b) on the opposite side of the convex portion (22) from the inclined side (the left side in FIG. 24(a)). In Example 44, the coverage rate (Rc1) (= Hx1 / H) of the first side (22b1) was fixed at 45%, and the coverage rate (Rc2) (= Hx2 / H) of the second side (22b2) was varied in the range of 35 to 55%.

[0648] The dimensions and shapes of each part of the model of the polarizing element (1) related to Example 44 are as follows.

[0649] P : 142 nm

[0650] W T : 17 nm

[0651] W B : 65 nm

[0652] W MAX : 65 nm

[0653] H : 225 nm

[0654] Hx1 : 101 nm (fixed value)

[0655] Hx2 : 79 nm, 90 nm, 101 nm, 113 nm, 124 nm (variable value)

[0656] Dt : 38 nm

[0657] Ds : 17.5 nm (maximum value)

[0658] Rc1 : 45 % (fixed value)

[0659] Rr1 : 55 % (fixed value)

[0660] Rc2 : 35 %, 40 %, 45 %, 50 %, 55 % (variable value)

[0661] Rr2 : 65 %, 60 %, 55 %, 50 %, 45 % (variable value)

[0662] θ : -45°, +45°

[0663] λ : 430 ∼ 680 nm

[0664] α : 10° (fixed value)

[0665] A simulation was performed on the model of the polarizing element (1) related to Example 44 fabricated as described above, and Tp, Ts, Rp, Rs, and Tp × Rs were calculated, respectively. At this time, the values ​​of Tp, Ts, Rp, and Rs were calculated for the case where "oblique incident light in the - direction (θ = -45°)" was incident and for the case where "oblique incident light in the + direction (θ = +45°)" was incident. In addition, for the values ​​of Tp, Ts, Rp, and Rs, the wavelength λ of the oblique incident light was varied in the range of 430 to 680 nm, and the average value of the multiple values ​​of Tp, Ts, Rp, and Rs calculated for each wavelength λ was used. In addition, the contrast (CR) of the transmitted light was also calculated by dividing Tp by Ts (CR = Tp / Ts).

[0666] The relationship between the Tp characteristic, Rs characteristic, Tp × Rs characteristic, contrast CR and the coverage rate (Rc2) of the first side (22b1) related to Example 44, obtained as described above, is shown in the graphs of FIGS. 24(b) to (e).

[0667] As shown in FIG. 24(c), the reflectance Rs of Example 44 maintains a high value of 90% or more regardless of the magnitude (35 to 55%) of the coverage rate (Rc2) in both cases of "oblique incident light in the - direction (θ = -45°)" and "oblique incident light in the + direction (θ = +45°)". Therefore, it can be seen that a high Rs of 90% or more can be secured regardless of Rc2, and excellent reflectivity (Rs characteristic) can be exhibited by the reflective film (30).

[0668] Meanwhile, as shown in FIGS. 24(b) and FIGS. 24(d), regarding the Tp characteristics and Tp × Rs characteristics, the behavior of the Tp characteristics and Tp × Rs characteristics according to the coverage rate (Rc2) differs depending on whether the incident direction of the obliquely incident light is the "- direction (θ = -45°)" or the "+ direction (θ = +45°)". Below, the reference values ​​of Tp (84%) and Tp × Rs (76%) of Comparative Example 40 (α = 0°) shown in FIG. 20 described above are compared with Tp and Tp × Rs of Example 44 (α = 10°) shown in FIG. 24, and the Tp characteristics and Tp × Rs characteristics of Example 44 are evaluated.

[0669] (1) - Obliquely incident light in the - direction (35 % ≤ Rc2 ≤ 55 %)

[0670] First, when the incident direction is the "- direction (θ = -45°)", in Example 44, if Rc2 is in the range of 35% or more and 55% or less, Tp becomes equal to or greater than the reference value (84%) as shown in FIG. 24(b), and as a result, Tp × Rs also becomes equal to or greater than the reference value (76%) as shown in FIG. 24(d). Therefore, in the case of "oblique incident light in the - direction (θ = -45°)", it can be seen that good transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) are obtained by adjusting Rc2 to the range of 35% or more and 55% or less.

[0671] In addition, it is desirable to adjust Rc2 to a range of 40% or more and 55% or less. As a result, as shown in FIG. 24(b), Tp becomes 85.5% or more, and as shown in FIG. 24(d), Tp × Rs becomes 77% or more. Therefore, it can be seen that better transmittance (Tp characteristics) and polarization separation characteristics (Tp × Rs characteristics) are obtained.

[0672] (2) + direction oblique incidence light (35 % ≤ Rc2 ≤ 45 %)

[0673] Meanwhile, when the incident direction is the "+ direction (θ = +45°)", in Example 44, if Rc2 is in the range of 35% or more and 45% or less, Tp becomes equal to or greater than the reference value (84%) as shown in FIG. 24(b), and as a result, Tp × Rs also becomes equal to or greater than the reference value (76%) as shown in FIG. 24(d). Therefore, it can be seen that in the case of "obliquely incident light in the + direction (θ = +45°)", good transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) are obtained by adjusting Rc2 to the range of 35% or more and 45% or less.

[0674] In addition, it is desirable to adjust Rc2 to a range of 40% or more and 45% or less. As a result, as shown in FIG. 24(b), Tp becomes about 85%, and as shown in FIG. 24(d), Tp × Rs becomes 76.5% or more. Therefore, it can be seen that better transmittance (Tp characteristics) and polarization separation characteristics (Tp × Rs characteristics) are obtained.

[0675] Also, regarding the contrast CR, as shown in FIG. 24(e), in both cases of "obliquely incident light in the - direction (θ = -45°)" and "obliquely incident light in the + direction (θ = +45°)", it can be seen that the contrast CR increases as the coverage rate (Rc2) increases, and in particular, the contrast CR increases rapidly at 45% or more.

[0676] From the results of Example 44 above, it can be seen that even if the coverage rate (Rc2) is non-uniform when manufacturing the grid, by tilting the convex portion (22), transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) equivalent to or greater than that of the standard (Comparative Example 40) can be obtained. Therefore, it can be said that by changing the installation direction of the grid tilt structure of the polarizing element (1) according to the incident direction (+ direction or - direction) of the incident oblique light, a polarizing element (1) with excellent transmittance (Tp characteristic) and polarization separation characteristic (Tp × Rs characteristic) for directional oblique light can be provided.

[0677] <2. Verification Results of the Composition of Organic Material (Photocurable Acrylic Resin for Imprinting)>

[0678] Examples 51 to 58 and Comparative Examples 51 to 57 were prepared as photocurable acrylic resins for imprinting.

[0679] The viscosity of the photocurable acrylic resin for imprinting related to Examples 51 to 58 and Comparative Examples 51 to 57 was measured. The viscosity was measured using a cone plate with a "Brookfield Viscometer" manufactured by Eiko Seiki Co., Ltd.

[0680] The YI values ​​of the cured products of the photocurable acrylic resins for imprinting related to Examples 51 to 58 and Comparative Examples 51 to 57 were measured after being held at 150°C for 500 hours (heat treatment). The YI values ​​were calculated based on the measurement results using the "UV-Visible-Near-Infrared Spectrophotometer V-770" manufactured by Nippon Bunko Co., Ltd. The measurement conditions and the method for calculating the YI values ​​were the same as those in the above embodiments.

[0681] For the cured products of the photocurable acrylic resin for imprinting related to Examples 51 to 58 and Comparative Examples 51 to 57, the average transmittance of the cured product for light in a wavelength range of 430 nm or more and 680 nm or less, and the average transmittance of the cured product for light in a wavelength range of 430 nm or more and 510 nm or less, were measured before heat treatment (maintained at 150 °C for 500 hours). In addition, after maintaining the cured products of the photocurable acrylic resin for imprinting related to Examples 51 to 58 and Comparative Examples 51 to 57 at 150 °C for 500 hours, the average transmittance of the cured product for light in a wavelength range of 430 nm or more and 680 nm or less, and the average transmittance of the cured product for light in a wavelength range of 430 nm or more and 510 nm or less, were measured. The average transmittance was calculated by measuring the transmittance at 1 nm intervals in the wavelength range of 430 nm or more and 680 nm or less, and by simply averaging the 251 obtained measurement data. The average transmittance was measured using the "UV-Visible Near-Infrared Spectrophotometer V-770" manufactured by Nippon Spectroscopic Corp.

[0682] The storage modulus at 30°C, 110°C, 120°C, and 130°C of the cured product of the photocurable acrylic resin for imprinting related to Examples 51 to 58 and Comparative Examples 51 to 57 was measured. The storage modulus was measured using the product name "DMA7100" manufactured by Hitachi High-Tech Co., Ltd. Sheets of the cured product of the photocurable acrylic resin for imprinting related to Examples 51 to 58 and Comparative Examples 51 to 57 were cut into lengths of 20 mm × widths of 3 mm, and in tensile mode, the temperature was increased at a rate of 5°C / min at a constant frequency (1 Hz) to measure the storage modulus at 25°C to 300°C.

[0683] The glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting related to Examples 51 to 58 and Comparative Examples 51 to 57 was measured. The glass transition temperature Tg was measured using the product name "DMA7100" manufactured by Hitachi High-Tech Co., Ltd. Sheets of the cured product of the photocurable acrylic resin for imprinting related to Examples 51 to 58 and Comparative Examples 51 to 57 were cut to a length of 20 mm × width of 3 mm, and the temperature was raised at a constant frequency (1 Hz) and a rate of 5 ℃ / min in tensile mode, and the measurement was performed by confirming the maximum value of the loss tangent tanδ at 25 ℃ to 300 ℃.

[0684] The composition and viscosity of the photocurable acrylic resins for imprinting in Examples 51 to 54 are shown in Table 1 below. The YI value, average transmittance, storage modulus, and glass transition temperature Tg of the cured products of the photocurable acrylic resins for imprinting related to Examples 51 to 54 are shown in Table 2 below.

[0685] The composition and viscosity of the photocurable acrylic resins for imprinting in Examples 55 to 58 are shown in Table 3 below. The YI value, average transmittance, storage modulus, and glass transition temperature Tg of the cured products of the photocurable acrylic resins for imprinting related to Examples 55 to 58 are shown in Table 4 below.

[0686] The composition and viscosity of the photocurable acrylic resins for imprinting in Comparative Examples 51 to 54 are shown in Table 5 below. The YI value, average transmittance, storage modulus, and glass transition temperature Tg of the cured products of the photocurable acrylic resins for imprinting related to Comparative Examples 51 to 54 are shown in Table 6 below.

[0687] The composition and viscosity of the photocurable acrylic resins for imprinting in Comparative Examples 55 to 57 are shown in Table 7 below. The YI value, average transmittance, storage modulus, and glass transition temperature Tg of the cured products of the photocurable acrylic resins for imprinting related to Comparative Examples 55 to 57 are shown in Table 8 below.

[0688] Also, the unit of the content in Tables 1, 3, 5, and 7 is mass%. Also, the viscosity in Tables 1, 3, 5, and 7 is the viscosity at 25°C [mPa·s].

[0689]

[0690]

[0691] [Example 51]

[0692] As shown in Table 1, Example 51 comprises only resin (A), resin (B), and resin (C) as photopolymerization components, and additionally includes a photopolymerization initiator. Phenylethyl acrylate (PEA) was used as resin (A). Phenylethyl acrylate was used under the product name "Viscot #192HP" manufactured by Osaka Organic Chemical Industry Co., Ltd. Bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene and 1,6-hexanediol diacrylate were used as resin (B). Bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene was used under the product name "KAYARAD R-604" manufactured by Nippon Explosives Co., Ltd. For 1,6-hexanediol diacrylate, the product name "A-HD-N" manufactured by Shin-Nakamura Chemical Industry Co., Ltd. was used. For resin (C), dipentaerythritol hexaacrylate (DPHA) was used. For dipentaerythritol hexaacrylate, the product name "KAYARAD DPHA" manufactured by Nippon Hwagyak Co., Ltd. was used. For photopolymerization initiator, the product name "Irgacure 819" manufactured by IGM Resins BV was used. In addition, in Example 51, the content of resin (A) in the total photopolymerization components was set to 33 mass%, the content of resin (B) to 66 mass%, and the content of resin (C) to 1 mass%. In addition, in Example 51, the ratio of 1,6-hexanediol diacrylate to bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene in resin (B) was set to 1:1. In addition, in Example 51, the content of the photopolymerization initiator was set to 0.5 mass% when the total content of the photopolymerization components was 100 mass%.

[0693] As shown in Table 1, the viscosity of the photocurable acrylic resin for imprinting in Example 51 was 12.32 mPa·s.

[0694] As shown in Table 2, the YI value after heat treatment of the cured product of the photocurable acrylic resin for imprinting of Example 51 was 1.1. From the above results, it was confirmed that a low YI value can be maintained even when heat treatment at 150°C is performed on the cured product of Example 51.

[0695] As shown in Table 2, in the cured product of the photocurable acrylic resin for imprinting of Example 51, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less before heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less before heat treatment was 91.7%. In addition, in the cured product of the photocurable acrylic resin for imprinting of Example 51, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less after heat treatment was 92.1%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less after heat treatment was 91.6%.

[0696] In the cured product of Example 51, the difference ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm or more and 680 nm or less before and after heat treatment became -0.2%. In the cured product of Example 51, the difference ΔA for light in the wavelength range of 430 nm or more and 510 nm or less before and after heat treatment became +0.1%. From the above results, it was confirmed that even if heat treatment at 150°C is performed on the cured product of Example 51, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less hardly decrease.

[0697] As shown in Table 2, the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 51 at 30°C is 2.0 × 10⁻⁶ 9 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 51 at 110°C was 1.3 × 10⁻⁶. 8 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 51 at 120°C was 1.3 × 10⁻⁶. 8 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 51 at 130°C was 1.4 × 10⁻⁶. 8 It was Pa. From the above results, the cured product of Example 51 was 2.0 × 10 before heat treatment. 9 It was confirmed that it has a high storage modulus of Pa. In addition, it was confirmed that the decrease in storage modulus is suppressed even when heat treatment at 150°C is performed on the cured product of Example 51.

[0698] As shown in Table 2, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of Example 51 was 70.7 °C. From the above results, it was confirmed that the cured product of Example 51, despite having a glass transition temperature Tg of less than 110 °C, can keep the YI value low after heat treatment at 150 °C, maintain a high average transmittance after heat treatment at 150 °C, and also suppress the decrease in storage modulus after heat treatment at 150 °C.

[0699] [Example 52]

[0700] As shown in Table 1, Example 52 differs from Example 51 only in the content ratio of resins (A) to resin (C). In Example 52, the content ratio of resin (A) in the total photopolymerization components was set to 30 mass%, the content ratio of resin (B) was set to 60 mass%, and the content ratio of resin (C) was set to 10 mass%. In addition, in Example 52, the ratio of 1,6-hexanediol diacrylate to bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene in resin (B) was set to 1 to 1.

[0701] As shown in Table 1, the viscosity of the photocurable acrylic resin for imprinting in Example 52 was 20.54 mPa·s. In addition, the photocurable acrylic resin for imprinting in Example 52 has a higher content of resin (C) compared to the photocurable acrylic resin for imprinting in Example 51. Thus, it is inferred that the viscosity of the photocurable acrylic resin for imprinting in Example 52 is higher than that of the photocurable acrylic resin for imprinting in Example 51.

[0702] As shown in Table 2, the YI value after heat treatment of the cured product of the imprint photocurable acrylic resin of Example 52 was 1.6. From the above results, it was confirmed that a low YI value can be maintained even when heat treatment at 150°C is performed on the cured product of Example 52. In addition, the photocurable acrylic resin for imprint of Example 52 has a higher resin (C) content compared to the photocurable acrylic resin for imprint of Example 51. Thus, it is inferred that the YI value of the cured product of the imprint photocurable acrylic resin of Example 52 is higher than the YI value of the cured product of the imprint photocurable acrylic resin of Example 51.

[0703] As shown in Table 2, in the cured product of the photocurable acrylic resin for imprinting of Example 52, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less before heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less before heat treatment was 91.8%. In addition, in the cured product of the photocurable acrylic resin for imprinting of Example 52, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less after heat treatment was 91.8%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less after heat treatment was 91.0%.

[0704] In the cured product of Example 52, the difference ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm or more and 680 nm or less before and after heat treatment became +0.1%. In the cured product of Example 52, the difference ΔA for light in the wavelength range of 430 nm or more and 510 nm or less before and after heat treatment became +0.8%. From the above results, it was confirmed that even if heat treatment at 150°C is performed on the cured product of Example 52, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less do not decrease significantly. In addition, the photocurable acrylic resin for imprinting of Example 52 has a higher content of resin (C) compared to the photocurable acrylic resin for imprinting of Example 51. As a result, it is inferred that the difference ΔA of the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less of the cured product of the photocurable acrylic resin for imprinting of Example 52 is slightly larger than the difference ΔA of the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Example 51.

[0705] As shown in Table 2, the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 52 at 30°C is 3.1 × 10⁻⁶ 9 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 52 at 110°C was 5.1 × 10⁻⁶. 8 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 52 at 120°C was 3.9 × 10⁻⁶. 8 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 52 at 130°C was 3.3 × 10⁻⁶.8 It was Pa. From the above results, the cured product of Example 52 was 3.1 × 10⁻⁶ before heat treatment. 9 It was confirmed that it has a high storage modulus of Pa. In addition, it was confirmed that the decrease in storage modulus is suppressed even when heat treatment at 150°C is performed on the cured product of Example 52. Furthermore, the photocurable acrylic resin for imprinting of Example 52 has a higher content of resin (C) compared to the photocurable acrylic resin for imprinting of Example 51. Thus, it is inferred that the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 52 is greater than the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 51.

[0706] As shown in Table 2, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of Example 52 was 103.1 °C. From the above results, it was confirmed that the cured product of Example 52, despite having a glass transition temperature Tg of less than 110 °C, can keep the YI value low after heat treatment at 150 °C, can maintain a high average transmittance after heat treatment at 150 °C, and can also suppress the decrease in storage modulus after heat treatment at 150 °C.

[0707] [Example 53]

[0708] As shown in Table 1, Example 53 differs from Examples 51 and 52 only in the content ratios of resins (A) to resins (C). In Example 53, the content ratio of resin (A) in the total photopolymerization components was set to 23.3 mass%, the content ratio of resin (B) was set to 46.7 mass%, and the content ratio of resin (C) was set to 30 mass%. In addition, in Example 53, the ratio of 1,6-hexanediol diacrylate to bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene in resin (B) was set to 1 to 1.

[0709] As shown in Table 1, the viscosity of the photocurable acrylic resin for imprinting in Example 53 was 68.12 mPa·s. In addition, the photocurable acrylic resin for imprinting in Example 53 has a higher content of resin (C) compared to the photocurable acrylic resin for imprinting in Example 52. Thus, it is inferred that the viscosity of the photocurable acrylic resin for imprinting in Example 53 is higher than that of the photocurable acrylic resin for imprinting in Example 52.

[0710] As shown in Table 2, the YI value after heat treatment of the cured product of the imprint photocurable acrylic resin of Example 53 was 2.3. From the above results, it was confirmed that a low YI value can be maintained even when heat treatment at 150°C is performed on the cured product of Example 53. In addition, the photocurable acrylic resin for imprint of Example 53 has a higher resin (C) content compared to the photocurable acrylic resin for imprint of Example 52. Thus, it is inferred that the YI value of the cured product of the imprint photocurable acrylic resin of Example 53 is higher than the YI value of the cured product of the imprint photocurable acrylic resin of Example 52.

[0711] As shown in Table 2, in the cured product of the photocurable acrylic resin for imprinting of Example 53, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less before heat treatment was 92.0%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less before heat treatment was 91.8%. In addition, in the cured product of the photocurable acrylic resin for imprinting of Example 53, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less after heat treatment was 91.8%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less after heat treatment was 90.7%.

[0712] In the cured product of Example 53, the difference ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm or more and 680 nm or less before and after heat treatment became +0.2%. In the cured product of Example 53, the difference ΔA for light in the wavelength range of 430 nm or more and 510 nm or less before and after heat treatment became +1.1%. From the above results, it was confirmed that even if heat treatment at 150°C is performed on the cured product of Example 53, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less hardly decrease. In addition, the photocurable acrylic resin for imprinting of Example 53 has a higher content of resin (C) compared to the photocurable acrylic resin for imprinting of Example 52. As a result, it is inferred that the difference ΔA in the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Example 53 is greater than the difference ΔA in the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Example 52.

[0713] As shown in Table 2, the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 53 at 30°C is 3.2 × 10⁻⁶ 9 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 53 at 110°C was 1.1 × 10⁻⁶. 9 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 53 at 120°C was 9.1 × 10⁻⁶. 8 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 53 at 130°C was 8.0 × 10⁻⁶. 8 It was Pa. From the above results, the cured product of Example 53 was 3.2 × 10⁻⁶ before heat treatment. 9 It was confirmed that it has a high storage modulus of Pa. In addition, it was confirmed that the decrease in storage modulus is suppressed even when heat treatment at 150°C is performed on the cured product of Example 53. Furthermore, the photocurable acrylic resin for imprinting of Example 53 has a higher content of resin (C) compared to the photocurable acrylic resin for imprinting of Example 52. Thus, it is inferred that the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 53 is greater than the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 52.

[0714] As shown in Table 2, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting of Example 53 was 103.8 °C. From the above results, it was confirmed that the cured product of Example 53, despite having a glass transition temperature Tg of less than 110 °C, can keep the YI value low after heat treatment at 150 °C, maintain a high average transmittance after heat treatment at 150 °C, and also suppress the decrease in storage modulus after heat treatment.

[0715] [Example 54]

[0716] As shown in Table 1, Example 54 differs from Examples 51 to 53 only in the content ratio of resin (A) to resin (C). In Example 54, the content ratio of resin (A) in the total photopolymerization components was set to 42 mass%, the content ratio of resin (B) was set to 43 mass%, and the content ratio of resin (C) was set to 15 mass%. Additionally, in Example 54, the content ratio of 1,6-hexanediol diacrylate in resin (B) was set to 42 mass%, and the content ratio of bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene was set to 1 mass%.

[0717] As shown in Table 1, the viscosity of the photocurable acrylic resin for imprinting in Example 54 was 13.45 mPa·s. In addition, the photocurable acrylic resin for imprinting in Example 54 has a higher content of 1,6-hexanediol diacrylate compared to Examples 52 and 53. As a result, it is inferred that the viscosity of the photocurable acrylic resin for imprinting in Example 54 is lower than that of the photocurable acrylic resin for imprinting in Examples 52 and 53.

[0718] As shown in Table 2, the YI value after heat treatment of the cured product of the imprint photocurable acrylic resin of Example 54 was 1.4. From the above results, it was confirmed that a low YI value can be maintained even when heat treatment at 150°C is performed on the cured product of Example 54. In addition, the content of 1,6-hexanediol diacrylate is higher in the imprint photocurable acrylic resin of Example 54 compared to Examples 52 and 53. Thus, it is inferred that the YI value of the cured product of the imprint photocurable acrylic resin of Example 54 is lower than the YI value of the cured products of the imprint photocurable acrylic resin of Examples 52 and 53.

[0719] As shown in Table 2, in the cured product of the photocurable acrylic resin for imprinting of Example 54, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less before heat treatment was 91.8%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less before heat treatment was 91.6%. In addition, in the cured product of the photocurable acrylic resin for imprinting of Example 54, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less after heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less after heat treatment was 91.3%.

[0720] In the cured product of Example 54, the difference ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm or more and 680 nm or less before and after heat treatment became -0.1%. In the cured product of Example 54, the difference ΔA for light in the wavelength range of 430 nm or more and 510 nm or less before and after heat treatment became +0.3%. From the above results, it was confirmed that even if heat treatment at 150°C is performed on the cured product of Example 54, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less are hardly reduced. In addition, the photocurable acrylic resin for imprinting of Example 54 has a higher content of 1,6-hexanediol diacrylate compared to Examples 52 and 53. As a result, it is inferred that the difference ΔA in the average transmittance of the cured product of the photocurable acrylic resin for imprinting of Example 54 is smaller than the difference ΔA in the average transmittance of the cured products of the photocurable acrylic resin for imprinting of Examples 52 and 53.

[0721] As shown in Table 2, the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 54 at 30°C is 2.3 × 10⁻⁶ 9 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 54 at 110°C was 1.9 × 10⁻⁶. 8 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 54 at 120°C was 2.2 × 10⁻⁶. 8 It was Pa. The storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 54 at 130°C was 2.3 × 10⁻⁶. 8It was Pa. From the above results, the cured product of Example 54 was 2.3 × 10⁻⁶ before heat treatment. 9 It was confirmed that it has a high storage modulus of Pa. In addition, it was confirmed that the decrease in storage modulus is suppressed even when heat treatment at 150°C is performed on the cured product of Example 54. Furthermore, the photocurable acrylic resin for imprinting of Example 54 has a higher content of resin (C) compared to Example 51. Thus, it is inferred that the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 54 is greater than the storage modulus of the cured product of the photocurable acrylic resin for imprinting of Example 51.

[0722] As shown in Table 2, the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 54 was 58.0 °C. From the above results, it was confirmed that the cured product of Example 54 can keep the YI value low after heat treatment at 150 °C, maintain a high average transmittance after heat treatment at 150 °C, and suppress the decrease in storage modulus after heat treatment at 150 °C, even though the glass transition temperature Tg is less than 110 °C. Furthermore, the photocurable acrylic resin for imprinting in Example 54 has a higher content of 1,6-hexanediol diacrylate compared to Examples 52 and 53. Thus, it is inferred that the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Example 54 is lower than the glass transition temperature Tg of the cured product of the photocurable acrylic resin for imprinting in Examples 52 and 53.

[0723]

[0724]

[0725] [Example 55]

[0726] As shown in Table 3, Example 55 differs from Example 54 only in the content ratio of 1,6-hexanediol diacrylate and bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene in resin (B). In Example 55, the content ratio of 1,6-hexanediol diacrylate in resin (B) was set to 1 mass%, and the content ratio of bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene was set to 42 mass%.

[0727] As shown in Table 3, the viscosity of the photocurable acrylic resin for imprinting in Example 55 was 85.01 mPa·s. In addition, compared to Example 54, the photocurable acrylic resin for imprinting in Example 55 has a lower content of 1,6-hexanediol diacrylate and a higher content of bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene. Thus, it is inferred that the viscosity of the photocurable acrylic resin for imprinting in Example 55 is higher than that of the photocurable acrylic resin for imprinting in Example 54.

[0728] As shown in Table 4, the YI value after heat treatment of the cured product of the photocurable acrylic resin for imprinting of Example 55 was 1.1. From the above results, it was confirmed that a low YI value can be maintained even when heat treatment at 150°C is performed on the cured product of Example 55.

[0729] As shown in Table 4, in the cured product of the photocurable acrylic resin for imprinting of Example 55, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less before heat treatment was 91.9%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less before heat treatment was 91.7%. In addition, in the cured product of the photocurable acrylic resin for imprinting of Example 55, the average transmittance for light in the wavelength range of 430 nm or more and 680 nm or less after heat treatment was 92.0%, and the average transmittance for light in the wavelength range of 430 nm or more and 510 nm or less after heat treatment was 91.5%.

[0730] In the cured product of Example 55, the difference ΔA (average transmittance before heat treatment - average transmittance after heat treatment) for light in the wavelength range of 430 nm or more and 680 nm or less before and after heat treatment became -0.2%. In the cured product of Example 55, the difference ΔA for light in the wavelength range of 430 nm or more and 510 nm or less before and after heat...

Claims

Claim 1 A wire grid polarizing element comprising a substrate made of an inorganic material, a grid structure integrally formed with a base portion formed on the substrate made of an organic material and a plurality of convex portions protruding from the base portion, and a functional film made of a metal material covering a portion of the convex portions, wherein the organic material is a cured product of a photocurable acrylic resin for imprinting containing a photopolymerization component, wherein the photopolymerization component comprises a resin (A) and a resin (B), wherein the resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and the resin (B) is a difunctional compound, wherein the content of the resin (A) relative to the entire photopolymerization component is 20 mass% or more and 42 mass% or less, and the content of the resin (B) relative to the entire photopolymerization component is 43 mass% or more and 66 mass% or less. Claim 2 A wire grid polarizing element according to claim 1, wherein the photopolymerization component further comprises a resin (C), the resin (C) is an acrylate monomer having three or more functional groups, and the content of the resin (C) relative to the entire photopolymerization component is 1 mass% or more and 30 mass% or less. Claim 3 A wire grid polarizing element according to claim 1 or 2, wherein the resin (A) is one or both of phenylethyl acrylate and benzyl acrylate. Claim 4 A wire grid polarizing element according to claim 1 or 2, wherein the resin (B) is one or more selected from the group consisting of (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene, and 1,6-hexanedioldiacrylate. Claim 5 In claim 4, the resin (B) comprises one of 1,6-hexanediol diacrylate, (octahydro-4,7-methano-1H-indenediyl)bis(methylene)diacrylate, and bisacrylic acid (2,2-dimethylethylene)(5-ethyl-1,3-dioxane-2,5-diyl)methylene, a wire grid polarizing element. Claim 6 In claim 2, the wire grid polarizing element, wherein the resin (C) comprises one or both of dipentaerythritol hexaacrylate and tris-(2-acryloxyethyl)isocyanurate. Claim 7 A wire grid polarizing element according to claim 1 or 2, wherein the viscosity of the photocurable acrylic resin for imprinting at 25°C is 90 mPa·s or less. Claim 8 A wire grid polarizing element according to claim 1 or 2, wherein, after maintaining the cured product of the photocurable acrylic resin for imprint at 150°C for 500 hours, the YI value of the cured product is 3.0 or less. Claim 9 In claim 1 or 2, the storage modulus of the cured product of the photocurable acrylic resin for imprinting at 30 ℃ is 2.0 × 10 9 The storage modulus of the cured product at 120°C, which is Pa or higher, is 1.3 × 10⁻⁶ 8 Wire grid polarizing element with Pa or higher. Claim 10 In claim 9, the storage modulus of the said cured product at 130 ℃ is 1.4 × 10⁻⁶ 8 Wire grid polarizing element with Pa or higher. Claim 11 A wire grid polarizing element according to claim 1 or 2, wherein, after maintaining the cured product of the photocurable acrylic resin for imprint at 150°C for 500 hours, the average transmittance of the cured product for light in a wavelength range of 430 nm or more and 680 nm or less is 91% or more, and the average transmittance of the cured product for light in a wavelength range of 430 nm or more and 510 nm or less is 90% or more. Claim 12 A wire grid polarizing element according to claim 1 or 2, wherein the convex jaw has a shape that tapers toward the end, with the width narrowing as it moves away from the base portion, and the functional film covers the tip of the convex jaw and the upper side of at least one side, and does not cover the lower side of both sides of the convex jaw and the base portion, and when the coverage rate (Rc) of the side of the convex jaw by the functional film is the ratio of the height (Hx) of the portion covered by the functional film on the side of the convex jaw to the height (H) of the convex jaw, the coverage rate (Rc) is 30% or more and 70% or less. Claim 13 A wire grid polarizing element according to claim 1 or 2, wherein at least the portion of the convex portion covered with the functional film is inclined at an inclination angle (α) greater than 0° and less than or equal to 15° with respect to the normal direction of the substrate. Claim 14 A wire grid polarizing element according to claim 13, wherein the convex portion is bent in the middle of the height direction of the convex portion, and the portion above the bent position of the convex portion is inclined at the inclination angle (α) with respect to the normal direction of the substrate. Claim 15 A wire grid polarizing element according to claim 13, wherein the entire convex portion is inclined at the inclination angle (α) with respect to the normal direction of the substrate. Claim 16 In claim 13, the wire grid polarizing element, wherein the inclination angle (α) is 5° or more and 10° or less. Claim 17 A wire grid polarizing element according to claim 13, wherein the functional film covers the leading edge and the upper side of both sides of the convex jaw portion, and the coverage rate (Rc) of both sides of the convex jaw portion by the functional film is 30% or more and 70% or less. Claim 18 A wire grid polarizing element according to claim 17, wherein the coverage rate (Rc) of the first side of the side on which the convex part is inclined among the two sides of the convex part is 35% or more and 50% or less. Claim 19 In claim 18, the wire grid polarizing element, wherein the coverage rate (Rc) of the first side is 40% or more and 53% or less. Claim 20 A wire grid polarizing element according to claim 17, wherein the coverage rate (Rc) of the second side opposite to the inclined side of the convex portion among the two sides of the convex portion is 35% or more and 55% or less. Claim 21 In claim 20, the wire grid polarizing element, wherein the coverage rate (Rc) of the second side is 35% or more and 45% or less. Claim 22 A method for manufacturing a wire grid polarizing element as described in claim 1 or 2 comprises: a process of forming a grid structure material made of an organic material on a substrate made of an inorganic material; a process of forming a grid structure in which a base portion formed on the substrate and a plurality of convex portions protruding from the base portion are integrally formed by performing nanoimprinting on the grid structure material; and a process of forming a functional film that covers a portion of the convex portions using a metal material, wherein the organic material is a cured product of a photocurable acrylic resin for imprinting comprising a photopolymerization component, wherein the photopolymerization component comprises a resin (A) and a resin (B), wherein the resin (A) is a monofunctional acrylate monomer having one or both of a phenyl group and a benzyl group, and the resin (B) is a difunctional compound, wherein the content of the resin (A) relative to the entire photopolymerization component is 20 mass% or more and 42 mass% or less, and the resin (B) relative to the entire photopolymerization component A method for manufacturing a wire grid polarizing element having a content of 43 mass% or more and 66 mass% or less. Claim 23 A method for manufacturing a wire grid polarizing element according to claim 22, wherein the photocurable acrylic resin for imprinting further comprises a photopolymerization initiator for polymerizing the photopolymerization component, and the process of forming the grid structure comprises mixing the resin (A) and the resin (B) and mixing the photopolymerization initiator into the mixed resin of the resin (A) and the resin (B). Claim 24 A method for manufacturing a wire grid polarizing element according to claim 22, wherein the photopolymerization component further comprises a resin (C), the resin (C) is an acrylate monomer having three or more functional groups, the content of the resin (C) relative to the entire photopolymerization component is 1 mass% or more and 30 mass% or less, and the process of forming the grid structure comprises producing a first mixed resin by mixing the resin (A) and the resin (B), and producing a second mixed resin by mixing the resin (C) with the first mixed resin. Claim 25 A projection display device comprising: a light source; a polarizing beam splitter positioned so that incident light from the light source is incident at an incident angle of 30° or more and 60° or less, and separating the incident light into a first polarization and a second polarization; a reflective liquid crystal display element positioned so that the first polarization reflected from the polarizing beam splitter or the second polarization transmitted through the polarizing beam splitter is incident, and reflecting and modulating the incident first polarization or the second polarization; and a lens positioned so that the first polarization or the second polarization reflected and modulated from the reflective liquid crystal display element is incident through the polarizing beam splitter, wherein the polarizing beam splitter is composed of a wire grid polarizing element as described in claim 1 or claim 2. Claim 26 A vehicle equipped with a projection display device as described in claim 25.

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