Organic member, and head mounted display

Abstract

To suppress damage and deformation of an optical member joined to a display element of a head mounted display.SOLUTION: An optical member 20 is joined to a display element 13 of a head mounted display 10. The optical member 20 includes a resin layer 30. The resin layer 30 includes a plurality of unit optical elements 35 arrayed so as to form an uneven shape 36. The loss elastic modulus of the resin layer 30 is 4×105 Pa or more and 2×106 Pa or less. A ratio of the loss elastic modulus to the storage elastic modulus of the resin layer 30 is 0.02 or more and 0.5 or less.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an optical member and a head-mounted display. [Background technology]

[0002] Head-mounted displays are known that are worn on the head of a viewer and display images in front of the viewer's eyes. Head-mounted displays are used for applications such as games, entertainment, and creative work by displaying virtual spaces. Head-mounted displays include a light source and a display element. Light from the light source passes through the display element to form an image that the viewer observes.

[0003] In order to ensure that an observer can properly view an image displayed by a head-mounted display, an optical member may be bonded to the display element of the head-mounted display. The optical member includes a plurality of unit optical elements for achieving a desired optical function. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-148977 Summary of the Invention [Problem to be solved by the invention]

[0005] An observer wearing a head-mounted display may move around. The head-mounted display may vibrate. The optical members bonded to the display elements of the head-mounted display may collide with other members. The impact of the collision may scratch or deform the optical members. Scratches or deformations of the optical members may be noticeable in images displayed by the head-mounted display or may reduce the optical function exhibited by the optical members, thereby degrading the quality of images displayed by the head-mounted display. The present disclosure aims to suppress scratches and deformations of optical members bonded to the display elements of a head-mounted display. [Means for solving the problem]

[0006] The optical member of the present disclosure is an optical member bonded to a display element of a head-mounted display, a first surface and a second surface opposite the first surface; a base material and a resin layer arranged from the first surface toward the second surface, the resin layer includes a plurality of unit optical elements arranged to form a concave-convex shape; The loss modulus of the resin layer is 4×10 5 Pa or more 2×10 6 Pa or less, The ratio of the loss modulus to the storage modulus of the resin layer is 0.02 or more and 0.5 or less. [Effects of the Invention]

[0007] According to the present disclosure, scratches and deformation of optical members bonded to display elements of a head-mounted display can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view schematically illustrating a head-mounted display. [Figure 2] FIG. 2 is a cross-sectional view of the head-mounted display. [Figure 3] FIG. 3 is a perspective view of the optical member. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the drawings accompanying this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of ease of illustration and understanding. Components shown in some drawings may be omitted in other drawings.

[0010] In this specification, terms such as "parallel," "orthogonal," and "identical," which specify shapes and geometric conditions and their degrees, as well as values ​​of lengths and angles, are not limited to their strict meanings but are interpreted to include a range of degrees within which similar functions can be expected.

[0011] In this specification, when multiple upper limit value candidates and multiple lower limit value candidates are listed for a parameter, the parameter may be a numerical range that combines any one upper limit value candidate and any one lower limit value candidate.

[0012] An embodiment of the present disclosure relates to the following [1] to

[12] . [1] An optical member bonded to a display element of a head-mounted display, A resin layer is provided, the resin layer includes a plurality of unit optical elements arranged to form a concave-convex shape; The loss modulus of the resin layer is 4×10 5 Pa or more 2×10 6 Pa or less, An optical member, wherein the ratio of the loss modulus to the storage modulus of the resin layer is 0.02 or more and 0.5 or less. [2] The optical member according to [1], wherein the radius of curvature near the ridge line of the concave-convex shape is 0.1 μm or more and 25 μm or less. [3] a first surface and a second surface opposite the first surface; the unit optical element forms the second surface, The optical member according to [1] or [2], wherein the pencil hardness Hm of the first surface and the pencil hardness He of the second surface satisfy the following relationship (i): He+3≧Hm≧He+2 (i) [4] An optical member bonded to a display element of a head-mounted display, a first surface and a second surface opposite the first surface; A resin layer is provided, the resin layer includes a plurality of unit optical elements arranged to form a concave-convex shape; An optical member, wherein the pencil hardness Hm of the first surface and the pencil hardness He of the second surface satisfy the following relationship (i): He+3≧Hm≧He+2 (i) [5] The optical member according to any one of [1] to [4], wherein the resin layer has a maximum logarithmic decrement of 0.4 or less by a rigid pendulum method. [6] An optical member bonded to a display element of a head-mounted display, A resin layer is provided, the resin layer includes a plurality of unit optical elements arranged to form a concave-convex shape; The optical member has a maximum logarithmic decrement of 0.4 or less, as measured by a rigid pendulum method. [7] The optical member according to any one of [1] to [6], wherein the resin layer has a maximum temperature of logarithmic decrement by a rigid pendulum method of 60° C. or higher. [8] The equilibrium elastic modulus of the resin layer is 1×10 8 The optical member according to any one of [1] to [7], wherein the optical member has a temperature of 1000 Pa or more. [9] The optical member according to any one of [1] to [8], wherein the resin layer has an elastic deformation rate of 40% or more at 25°C.

[10] An optical member according to any one of [1] to [9], wherein the length of at least one of the unit optical elements along the arrangement direction is different from the length of the other unit optical elements along the arrangement direction.

[11] An optical member according to any one of [1] to

[10] , wherein the height of the uneven shape formed by at least one of the unit optical elements is different from the height of the uneven shape formed by the other unit optical elements.

[12] [1] to

[11] , and the optical member according to any one of [1] to

[11] . a display element bonded to the optical member.

[0013] An embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 shows a head-mounted display 10 according to the embodiment. The head-mounted display 10 is worn on the head of a viewer when in use. The head-mounted display 10 displays an image in front of the viewer's eyes 1. FIG. 2 shows an exploded cross-sectional view of the head-mounted display 10. As shown in FIG. 2, the head-mounted display 10 has a display element 13, a bonding layer 15, an optical member 20, a prism sheet 17, and a surface light source 19.

[0014] The display element 13 forms an image by transmitting light from the surface light source 19. The display element 13 may be, for example, a liquid crystal panel. As an example, a case where the display element 13 is a liquid crystal panel will be described. The liquid crystal panel can form an image by controlling the transmission or blocking of light from the surface light source 19 for each region (subpixel) that forms a pixel.

[0015] A liquid crystal panel has two polarizing plates and a liquid crystal layer disposed between the two polarizing plates. The polarizing plates separate incident light into two orthogonal polarization components (e.g., P-wave and S-wave), transmit the linearly polarized component (e.g., P-wave) vibrating in one direction (parallel to the transmission axis) and absorb the linearly polarized component (e.g., S-wave) vibrating in the other direction (parallel to the absorption axis) perpendicular to the first direction. A voltage can be applied to each pixel-forming region of the liquid crystal layer. The orientation of the liquid crystal molecules in the liquid crystal layer changes depending on whether or not a voltage is applied. For example, a polarized component in a specific direction rotates its polarization direction by 90° when passing through a liquid crystal layer with no voltage applied, and maintains its polarization direction when passing through a liquid crystal layer with a voltage applied. In this case, the application of a voltage to the liquid crystal layer can control whether the polarized component vibrating in a specific direction that has passed through one polarizing plate is further transmitted through the other polarizing plate or is absorbed and blocked. As a result, in the liquid crystal panel, the transmission or blocking of light from the surface light source 19 is controlled for each region where pixels are formed.

[0016] The bonding layer 15 bonds the display element 13 and the optical member 20. The bonding layer 15 is a thin film. The bonding layer 15 may be transparent. The bonding layer 15 may be an optical clear adhesive (OCA) sheet.

[0017] In this specification, "transparent" means a material having a degree of transparency that allows viewing from one side of the material to the other side through the material, e.g., a visible light transmittance of 30% or more, more preferably 70% or more. In this specification, visible light transmittance is defined as the average value of the total light transmittance at each wavelength measured in 1-nm increments within the wavelength range of 380 nm to 780 nm using a spectrophotometer (Shimadzu Corporation's "UV-3600i Plus," compliant with JIS K0115). The angle of incidence when measuring visible light transmittance is taken as 0° unless a specific transmission direction is specified. The angle of incidence is the angle between the normal to the incident surface and the direction of propagation of incident light, and is less than 90°.

[0018] The prism sheet 17 changes the traveling direction of light from the surface light source 19. Specifically, the prism sheet 17 can change the traveling direction of light from the surface light source 19 to a direction approximately perpendicular to the display element 13, allowing the light to enter the display element 13. The prism sheet 17 has a plurality of unit prisms arranged in one direction. Each unit prism extends in a direction non-parallel to the arrangement direction. The head mounted display 10 may have a plurality of prism sheets 17. In this case, the extending directions of the unit prisms of each prism sheet 17 may be different from each other.

[0019] The surface light source 19 emits light in a planar manner. The surface light source 19 may be any of an edge-light type, a direct-illumination type, and a back-illumination type. As an example, a case where the surface light source 19 is an edge-light type light source will be described. The surface light source 19 includes a light guide plate and a light source disposed on one side of the light guide plate. The light guide plate includes a light-entering surface facing the light source, a light-exiting surface facing the prism sheet 17, and a back surface opposite the light-exiting surface. Light entering the light guide plate from the light-entering surface is guided by being totally reflected inside the light guide plate by the light-exiting surface and the back surface toward the opposite surface opposite the light-entering surface. When a portion of the light guided inside the light guide plate reaches an angle less than the critical angle of total reflection at the light-exiting surface, the light is emitted from the light-exiting surface. The light source may be, for example, a linear fluorescent lamp such as a cold cathode fluorescent lamp, a point-shaped LED (light-emitting diode), an incandescent light bulb, or the like.

[0020] The optical element 20 exhibits a desired optical function. The optical function of the optical element 20 makes it easier for a viewer wearing the head-mounted display 10 to view an image. The optical element 20 is bonded to the display element 13 of the head-mounted display 10 by a bonding layer 15. The optical element 20 is positioned between the display element 13 and the prism sheet 17. FIG. 3 shows an enlarged perspective view of the optical element 20. The optical element 20 includes a first surface 20A and a second surface 20B. The first surface 20A and the second surface 20B are the main surfaces of the optical element 20. The second surface 20B is the surface opposite the first surface 20A. As shown in FIG. 2, the second surface 20B faces the prism sheet 17. As shown in FIG. 3, the optical element 20 includes a substrate 21 and a resin layer 30, in this order, from the first surface 20A to the second surface 20B. In the example shown in FIG. 3, the base material 21 forms the first surface 20A of the optical member 20, and the resin layer 30 forms the second surface 20B of the optical member 20.

[0021] The substrate 21 supports the resin layer 30. The substrate 21 is thin plate-shaped. The thickness of the substrate 21 may be 5 μm or more, 15 μm or more, 25 μm or more, 150 μm or more, or 120 μm or less. The substrate 21 is transparent. The material of the substrate 21 may be any of glass, acrylic resin, polycarbonate resin, vinyl chloride resin, polymethacrylimide resin, polyester resin, and cyclic olefin copolymers such as COP resin and COC resin. The substrate 21 may be removed from the optical member 20 by peeling or the like.

[0022] The resin layer 30 is provided to provide the optical member 20 with an optical function. The resin layer 30 may function as a lens, for example. The resin layer 30 refracts light to provide a desired optical function. The shape of the resin layer 30, more specifically, the concave-convex shape 36 of the unit optical elements 35 described below, is determined according to the optical function to be provided. The resin layer 30 is transparent. The resin layer 30 includes a base 31 and a plurality of unit optical elements 35 provided on the base 31. The base 31 is a flat plate-shaped portion having a pair of parallel main surfaces. The unit optical elements 35 are arranged in one direction on one main surface of the base 31. The arrangement direction of the unit optical elements 35 may be the same as or different from the arrangement direction of the unit prisms of the prism sheet 17. The unit optical elements 35 extend in a direction non-parallel to the arrangement direction.

[0023] The plurality of unit optical elements 35 are arranged to form a concave-convex shape 36. The plurality of unit optical elements 35 form the concave-convex shape 36 on the second surface 20B of the optical member 20. The concave-convex shape 36 formed by the unit optical elements 35 exhibits an optical function. The unit optical elements 35 may have the same shape or different shapes from each other. The unit optical elements 35 have a shape that allows the optical member 20 to exhibit a desired optical function. For example, the unit optical elements 35 may form the concave-convex shape 36 so as to form a lens structure.

[0024] The cross-sectional shape of the unit optical elements 35 is a shape that exhibits a desired optical function. In the example shown, the cross-sectional shape of the unit optical elements 35 is a triangle. The cross-sectional shape of the unit optical elements 35 may be any of a shape consisting of only straight lines, such as a triangle, rectangle, pentagon, or hexagon, a shape consisting of only curved lines, such as a circle, ellipse, parabola, hyperbola, or sinusoidal curve, or a shape containing both straight lines and curved lines. The cross-sectional shape of at least one unit optical element 35 may be different from the cross-sectional shapes of the other unit optical elements 35.

[0025] The length of each unit optical element 35 along the arrangement direction may be non-uniform. The length of at least one unit optical element 35 along the arrangement direction may be different from the lengths of the other unit optical elements 35 along the arrangement direction. The lengths of each unit optical element 35 along the arrangement direction may be different from one another. The length of each unit optical element 35 along the arrangement direction may be 10 μm or more, or 500 μm or less.

[0026] The height of the concave-convex shape 36 formed by each unit optical element 35 may be non-uniform. The height of the concave-convex shape 36 formed by at least one unit optical element 35 may be different from the height of the concave-convex shape 36 formed by the other unit optical elements 35. The heights of the concave-convex shape 36 formed by each unit optical element 35 may be different from each other. The height of the concave-convex shape 36 formed by each unit optical element 35 may be 5 μm or more or 250 μm or less. The difference between the maximum height and the minimum height of the concave-convex shape 36 formed by each unit optical element 35 may be 1 μm or more or 10 μm or less. The height of the concave-convex shape 36 formed by each unit optical element 35 refers to the distance from the base 31 to the furthest part of the concave-convex shape 36 formed by the unit optical element 35.

[0027] The radius of curvature near the ridge line 37 of the concave-convex shape 36 may be 0.1 μm or more, 0.5 μm or more, 0.7 μm or more, 25 μm or less, or 10 μm or less. The ridge line 37 of the concave-convex shape 36 refers to a line formed by connecting the furthest portions of the concave-convex shape 36 formed by the unit optical elements 35 from the base 31 in a cross section taken along the arrangement direction of the unit optical elements 35 forming the concave-convex shape 36 in the direction in which the unit optical elements 35 extend. The vicinity of the ridge line 37 of the concave-convex shape 36 may be, for example, a shape of the concave-convex shape 36 within 1 μm of the ridge line 37 of the concave-convex shape 36. The shape of the concave-convex shape 36 near the ridge line 37 may be a circle, ellipse, hyperbola, parabola, sinusoid, cardioid, cycloid, or the like. If the shape near the ridge line 37 of the concave-convex shape 36 is not a circle, the radius of the radius of the approximation circle that matches the shape of the ridge line 37 is taken as the radius of the radius of the circle. The radius of curvature near the ridge line 37 of the uneven shape 36 is identified from an image of the cross section of the resin layer 30. The image of the cross section of the resin layer 30 is obtained by a scanning electron microscope.

[0028] The angle formed by the uneven shape 36 at the furthest part of the uneven shape 36 in a cross section along the arrangement direction of the unit optical elements 35 that form the uneven shape 36, in other words, the apex angle at the ridge line 37 of the uneven shape 36, may be 80° or more or 110° or less.

[0029] The resin layer 30 has appropriate physical properties to prevent scratches and deformation of the optical member. The resin layer 30 has one or more of the physical properties described below. The resin layer 30 may have a combination of two or more of the physical properties described below.

[0030] The ratio of the loss modulus to the storage modulus of the resin layer may be 0.02 or more, 0.04 or more, 0.5 or less, or 0.2 or less. The ratio of the loss modulus to the storage modulus of the resin layer represents the diffusion component to the storage component of energy generated in the resin layer by force or strain. In other words, the ratio of the loss modulus to the storage modulus represents the shock absorption (diffusion) properties. The higher the ratio of the loss modulus to the storage modulus, the higher the shock absorption properties.

[0031] The loss modulus of the resin layer 30 is 4×10 5 Pa or more, 2 × 10 6 The loss modulus represents viscous properties. A higher loss modulus indicates a higher viscosity.

[0032] In this specification, the storage modulus and loss modulus are measured by dynamic viscoelasticity measurement using a viscoelasticity measuring device (Viscoelasticity Spectrometer DMS6100 manufactured by SII NanoTechnology, Inc.) The measurement conditions are constant: temperature 25°C, frequency 10 Hz, compression jig area 5 cm × 5 cm, strain amplitude 1.0%, and static load 2.45 N (250 gf).

[0033] The equilibrium elastic modulus of the resin layer 30 is 1×10 8 Pa or more, 2 × 10 8 Pa or more, 6 × 10 8 Pa or less, 4 × 10 8 The equilibrium modulus may be equal to or less than 100 Pa. The equilibrium modulus represents the storage modulus when the state changes from a viscoelastic body to a rubber bullet body when the glass transition temperature is exceeded.

[0034] In this specification, the equilibrium modulus is the value of the storage modulus measured by dynamic viscoelasticity measurement using a viscoelasticity measuring device (Viscoelasticity Spectrometer DMS6100 manufactured by SII NanoTechnology, Inc.) The measurement conditions were constant: temperature 160°C, frequency 1 Hz, compression jig area 5 cm × 5 cm, strain amplitude 1.0%, and static load 2.45 N (250 gf).

[0035] The elastic deformation rate of the resin layer 30 at 25°C may be 40% or more, 45% or more, 70% or less, or 55% or less. The elastic deformation rate refers to the ratio of the workload of elastic deformation to the total workload of elastic deformation and plastic deformation. The elastic deformation rate represents the rate at which an object is restored to its original shape when deformed. The higher the elastic deformation rate, the easier it is to restore the deformation.

[0036] In this specification, the elastic deformation rate is measured using a microhardness tester (device name: Fischerscope H-100, manufactured by Fischer Instruments). The indenter is an MK320, and the measuring device is an HU-100 (manufactured by Fischer Instruments). The indenter is driven as follows: The indenter is driven so that the force applied by the indenter to the resin layer 30 to be measured becomes 300 mN after 20 seconds. When the force applied by the indenter to the measurement object reaches 300 mN, the force of 300 mN is maintained for 60 seconds. Thereafter, the indenter is driven so that the force applied by the indenter to the measurement object becomes 0.4 mN after 4 seconds. When the force applied by the indenter to the measurement object reaches 0.4 mN, the force of 0.4 mN is maintained for 60 seconds. While the indenter is being driven, the elastic deformation rate is measured using analysis software (WIN-HCU, manufactured by Fischer Instruments).

[0037] The pencil hardness Hm of the first surface 20A and the pencil hardness He of the second surface 20B of the optical member 20 may satisfy the following relationship (i). He+3≧Hm≧He+2 (i) The pencil hardness indicates the hardness of each surface.

[0038] In relationship (i), a one-unit increase in hardness on the pencil hardness scale is +1. The pencil hardness scale, from softest to hardest, is 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, and 6H. On the pencil hardness scale, for example, "+1 unit" relative to "HB" means "F," which is the next higher hardness unit, and "+2 units" means "H," which is the next higher hardness unit. For example, if He is 2B, relationship (i) means F≧Hm≧HB.

[0039] The pencil hardness Hm of the first surface 20A may be B or higher.

[0040] In this specification, pencil hardness is measured using a pencil hardness tester (No. 431 Pencil Scratch Coating Hardness Tester manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K5600-5-4:1999. The pencil hardness is measured by applying a load of 1000 g to the tip of the pencil across a sample whose pencil hardness is to be measured in a horizontal position, while moving the pencil at a speed of 1 mm / s.

[0041] The maximum logarithmic damping factor of the resin layer 30, as determined by the rigid pendulum method, may be 0.1 or more, 0.2 or more, 0.4 or less, or 0.3 or less. The logarithmic damping factor represents the logarithmic damping ratio of free damped vibration when viscoelasticity changes due to heating. The logarithmic damping factor is maximum near the glass transition temperature. The maximum logarithmic damping factor represents the logarithmic damping ratio of free damped vibration at the glass transition temperature. The maximum logarithmic damping factor is an index representing the viscoelasticity of a material.

[0042] The maximum temperature of the logarithmic decrement of the resin layer 30 measured by the rigid pendulum method may be 60° C. or higher, 80° C. or higher, or 150° C. or lower. The maximum temperature of the logarithmic decrement represents the glass transition temperature.

[0043] In this specification, the rigid pendulum method, as defined in ISO 12013, is a method for evaluating the surface properties of a solid by analyzing the damping process of the pendulum's oscillations using a rigid pendulum. The fulcrum of the pendulum is located on the surface of the object being measured. In this specification, the maximum logarithmic attenuation rate and the maximum temperature of the logarithmic attenuation rate using the rigid pendulum method refer to the maximum attenuation rate and maximum temperature obtained when a pipe-edge rigid pendulum is used, oscillating around the fulcrum at the point of contact with the lens, and the temperature is raised from 30°C to 150°C at a rate of 3°C / min.

[0044] The refractive index of the resin layer 30 may be 1.50 or more, 1.53 or more, 1.70 or less, or 1.57 or less. The refractive index value is measured with an Abbe refractometer (for example, RX-7000α manufactured by Atago Co., Ltd.).

[0045] The material of the resin layer 30 may be a thermoplastic resin or a cured product of a curable resin. The curable resin may be a photocurable resin. The photocurable resin may be, for example, an ultraviolet curable resin or an ionizing radiation curable resin.

[0046] The thermoplastic resin may be, for example, a homopolymer of a (meth)acrylic acid ester such as polymethyl(meth)acrylate or polybutyl(meth)acrylate, or a copolymer of a (meth)acrylic acid ester such as a methyl(meth)acrylate-butyl(meth)acrylate copolymer ("(meth)acrylic acid" means acrylic acid or methacrylic acid), a polyester such as polyethylene terephthalate or polybutylene terephthalate, polycarbonate, polystyrene, or polymethylpentene.

[0047] The UV-curable resin may contain a reactive prepolymer and a monomer component. The reactive prepolymer may be, for example, epoxy (meth)acrylate, urethane (meth)acrylate, or polyester (meth)acrylate. The monomer component may be a monofunctional monomer or a polyfunctional monomer. Examples of the monofunctional monomer include vinyl monomers such as N-vinylpyrrolidone, N-vinylcaprolactone, vinylimidazole, vinylpyridine, and styrene, phenoxyethyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, and baramol phenanthroline. The monomer may be a (meth)acrylic acid ester monomer such as methylphenoxyethyl (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, orthophenylphenoxyethyl (meth)acrylate, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylate, or acryloylmorpholine, or a (meth)acrylamide derivative.Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, bisphenol A poly The copolymer may be ethoxydiol di(meth)acrylate, bisphenol A polypropoxydiol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glyceryl tri(meth)acrylate, propoxylated glyceryl tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0048] The ionizing radiation curable resin contains a monomer and / or a prepolymer that is polymerized and cured by a reaction such as crosslinking under ionizing radiation. The monomer may be, for example, a radical polymerizable monomer or a cationically polymerizable monomer. The prepolymer (or oligomer) may be a radical polymerizable prepolymer or a cationically polymerizable prepolymer. The radical polymerizable monomer may be any of various (meth)acrylates, for example, monofunctional (meth)acrylates such as methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentenyl (meth)acrylate, and polyfunctional (meth)acrylates such as dipropylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. The cationically polymerizable monomer may be, for example, any of alicyclic epoxides such as 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexenecarboxylate, glycidyl ethers such as bisphenol A diglycidyl ether, vinyl ethers such as 4-hydroxybutyl vinyl ether, and oxetanes such as 3-ethyl-3-hydroxymethyloxetane. The radically polymerizable prepolymer may be, for example, any of various (meth)acrylate prepolymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, triazine (meth)acrylate, and silicone (meth)acrylate, polythiol-based prepolymers such as trimethylolpropane trithioglycolate and pentaerythritol tetrathioglycolate, and unsaturated polyester prepolymers.The cationically polymerizable prepolymer may be, for example, a novolac-based epoxy resin prepolymer, an aromatic vinyl ether-based resin prepolymer, or the like.

[0049] The ionizing radiation curable resin may contain a photopolymerization initiator, such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-hydroxy-2-methyl-1-phenyl-propane-1-ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, or a combination thereof.

[0050] As a specific example, the proportions of each resin contained in the ionizing radiation curable resin may be 5 to 50 parts by weight of epoxy (meth)acrylate, 5 to 50 parts by weight of urethane (meth)acrylate, 1 to 60 parts by weight of monofunctional monomer, 5 to 30 parts by weight of polyfunctional monomer, and 0.01 to 10 parts by weight of photopolymerization initiator.

[0051] The resin layer 30 may contain silicone, an antioxidant, a polymerization inhibitor, a release agent, an antistatic agent, an ultraviolet stabilizer, an antifoaming agent, a solvent, a non-reactive acrylic resin, a non-reactive urethane resin, a non-reactive polyester resin, a pigment, a dye, a diffusing agent, etc.

[0052] A resin layer 30 having one or more of the above-described physical properties can be obtained by appropriately adjusting the material of the resin layer 30. To obtain a resin layer 30 having one or more of the above-described physical properties, the material of the resin layer 30 may be an appropriate combination of two or more of the above-described materials.

[0053] Head-mounted displays are required to be thin so as not to interfere with the viewer's wearing of the display. To make head-mounted displays thin, the components included in the head-mounted display are placed close to each other. The components included in the head-mounted display are likely to come into contact with each other. A viewer wearing a head-mounted display may move around, which can cause the head-mounted display to vibrate. The vibrations cause the components included in a particularly thin head-mounted display to come into contact and rub against each other. This can cause scratches and deformations in the optical components included in the head-mounted display. Because the head-mounted display is located in front of the viewer's eyes, scratches on the optical components are easily visible in the images displayed by the head-mounted display. Scratches and deformations on the optical components can reduce the optical functions of the optical components, thereby degrading the quality of the images displayed by the head-mounted display.

[0054] One way to prevent scratches and deformation of optical members is to make the materials of the optical members hard and resistant to deformation. However, even if the optical members are made of a hard and resistant material, when they are bonded to the display element of a head-mounted display, scratches and deformation occur due to repeated vibrations caused by an observer wearing the head-mounted display moving around or using the head-mounted display for a long period of time.

[0055] In the optical member 20 of this embodiment, the loss modulus of the resin layer 30 is 4×10 5 Pa or more 2×10 6The resin layer 30 has a loss modulus of 0.02 or more and a storage modulus of 0.5 or less. The resin layer 30 can absorb external impacts because the loss modulus of the resin layer 30 is not too low and the ratio of the loss modulus of the resin layer 30 to the storage modulus of the resin layer 30 is not too low. The optical member 20 including the resin layer 30 is less susceptible to damage. The resin layer 30 has a sufficiently low loss modulus and a sufficiently low ratio of the loss modulus of the resin layer 30 to the storage modulus of the resin layer 30, so that the resin layer 30 returns to its original shape even if it is deformed by an external impact or the like. Deformation of the optical member 20 can be suppressed. The optical member 20 can maintain its optical function due to the shape of the resin layer 30.

[0056] In the optical member 20 of this embodiment, the radius of curvature near the ridgeline of the uneven shape 36 formed by the unit optical elements 35 of the resin layer 30 is 0.1 μm or more and 25 μm or less. Because the radius of curvature near the ridgeline of the uneven shape 36 is sufficiently large, the optical member 20 including the resin layer 30 is less likely to be damaged even if the resin layer 30 comes into contact with another member. Because the radius of curvature near the ridgeline of the uneven shape 36 is not too large, the uneven shape 36 can be properly formed by the unit optical elements 35. The optical member 20 can properly exhibit the optical function provided by the uneven shape 36.

[0057] In the optical member 20 of this embodiment, the pencil hardness Hm of the first surface 20A and the pencil hardness He of the second surface 20B satisfy the following relationship (i). He+3≧Hm≧He+2 (i) The optical member 20 is wound into a roll before being bonded to the display element 13 of the head-mounted display 10. The first surface 20A and the second surface 20B of the optical member 20 are in contact with each other. If the pencil hardness is high, the first surface 20A and the second surface 20B of the optical member 20 are less likely to be scratched by other members, but if the pencil hardness is too high, the first surface 20A and the second surface 20B of the optical member 20 may scratch each other. When the pencil hardness Hm of the first surface 20A and the pencil hardness He of the second surface 20B satisfy the above-mentioned relationship (i), the first surface 20A and the second surface 20B of the optical member 20 are less likely to be scratched even if the first surface 20A and the second surface 20B of the optical member 20 rub against each other.

[0058] In the optical member 20 of this embodiment, the maximum logarithmic attenuation of the resin layer 30 measured by the rigid pendulum method is 0.4 or less. A sufficiently small maximum logarithmic attenuation results in a sufficiently large equilibrium elastic modulus. Even if the resin layer 30 is deformed by an external impact or the like, it returns to its original shape. Deformation of the optical member 20 can be suppressed. The optical member 20 can maintain the optical function due to the shape of the resin layer 30. Furthermore, the maximum logarithmic attenuation of the resin layer 30 measured by the rigid pendulum method may be 0.1 or less. A sufficiently large maximum attenuation rate means that the resin layer 30 is not too hard and is unlikely to damage members facing the resin layer 30.

[0059] In the optical element 20 of this embodiment, the maximum temperature of the logarithmic decrement of the resin layer 30 measured by the rigid pendulum method is 60°C or higher. Since the maximum temperature of the logarithmic decrement is sufficiently high, the resin layer 30 is less likely to soften due to temperature. Even if the resin layer 30 is subjected to an external impact, the resin layer 30 is less likely to deform. Deformation of the optical element 20 can be suppressed. The optical element 20 can maintain its optical function due to the shape of the resin layer 30.

[0060] In the optical member 20 of this embodiment, the equilibrium elastic modulus of the resin layer 30 is 1×10 8 The equilibrium elastic modulus of the resin layer 30 is equal to or higher than 1 / 2 Pa. When the resin layer 30 has a sufficiently high equilibrium elastic modulus, the resin layer 30 returns to its original shape even if it is deformed by an external impact or the like. This makes it possible to suppress deformation of the optical member 20. The optical member 20 can maintain its optical function due to the shape of the resin layer 30.

[0061] In the optical member 20 of this embodiment, the elastic deformation rate of the resin layer 30 at 25°C is 40% or more. Since the elastic deformation rate of the resin layer 30 is sufficiently high, even if the resin layer 30 is deformed by an external impact or the like, it returns to its original shape. Deformation of the optical member 20 can be suppressed. The optical member 20 can maintain its optical function due to the shape of the resin layer 30.

[0062] In the optical member 20 of this embodiment, the length along the arrangement direction of at least one unit optical element 35 is different from the length along the arrangement direction of the other unit optical elements 35. The portion where the optical member 20 comes into contact with other members is the protruding portion of the uneven shape 36 formed by the unit optical elements 35. Since the length along the arrangement direction of the unit optical elements 35 is non-uniform, the portion where the optical member 20 comes into contact with other members also becomes non-uniform. In the head-mounted display 10, the portion where the optical member 20 comes into contact with other members becomes less noticeable. This makes it possible to suppress deterioration in the quality of images displayed by the head-mounted display 10.

[0063] In the optical member 20 of this embodiment, the height of the uneven shape 36 formed by at least one unit optical element 35 is different from the height of the uneven shape 36 formed by the other unit optical elements 35. The portion of the optical member 20 that comes into contact with other members is limited to the unit optical element 35 where the uneven shape 36 formed has the greatest height. The uneven shape 36 having a non-uniform height reduces the area where the resin layer 30 comes into contact with other members. Even if the optical member 20 comes into contact with other members, the optical member 20 including the resin layer 30 is less likely to be damaged.

[0064] The aspects of the present disclosure are not limited to the above-described embodiments, but include various modifications that may be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the contents of the above-described embodiments. Various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and intent of each disclosure derived from the contents defined in the claims and their equivalents. [Explanation of symbols]

[0065] 1 eye 10 Head-mounted display 13 Display element 15 Bonding layer 17 Prism sheet 19 Area light source 20 Optical Components 20A Page 1 20B 2nd side 21 Base material 30 resin layer 31 Base 35 unit optical elements 36 Uneven shape 37 Ridgeline

Claims

1. An optical member bonded to a display element of a head-mounted display, A resin layer is provided, the resin layer includes a plurality of unit optical elements arranged to form a concave-convex shape; The loss modulus of the resin layer is 4×10 ５ Pa or more 2×10 ６ Pa or less, An optical member, wherein the ratio of the loss modulus to the storage modulus of the resin layer is 0.02 or more and 0.5 or less.

2. 2. The optical member according to claim 1, wherein the radius of curvature near the ridge line of the concave-convex shape is 0.1 μm or more and 25 μm or less.

3. a first surface and a second surface opposite the first surface; the unit optical element forms the second surface, The optical member according to claim 1 , wherein a pencil hardness Hm of the first surface and a pencil hardness He of the second surface satisfy the following relationship (i): He+3≧Hm≧He+2...(i)

4. An optical member bonded to a display element of a head-mounted display, a first surface and a second surface opposite the first surface; A resin layer is provided, the resin layer includes a plurality of unit optical elements arranged to form a concave-convex shape; the unit optical element forms the second surface, An optical member, wherein the pencil hardness Hm of the first surface and the pencil hardness He of the second surface satisfy the following relationship (i): He+3≧Hm≧He+2...(i)

5. 5. The optical member according to claim 1, wherein the resin layer has a maximum logarithmic decrement of 0.4 or less as measured by a rigid pendulum method.

6. An optical member bonded to a display element of a head-mounted display, A resin layer is provided, the resin layer includes a plurality of unit optical elements arranged to form a concave-convex shape; An optical member, wherein the resin layer has a maximum logarithmic decrement of 0.4 or less as measured by a rigid pendulum method.

7. 7. The optical member according to claim 6, wherein the resin layer has a maximum temperature of logarithmic decrement measured by a rigid pendulum method of 60°C or higher.

8. The equilibrium elastic modulus of the resin layer is 1×10 ８ The optical member according to claim 6 , wherein the viscosity is 100 Pa or more.

9. 7. The optical member according to claim 6, wherein the resin layer has an elastic deformation rate of 40% or more at 25°C.

10. 7. The optical member according to claim 1, wherein a length of at least one of the unit optical elements along the arrangement direction is different from a length of the other unit optical elements along the arrangement direction.

11. 7. The optical member according to claim 1, wherein the height of the concave-convex shape formed by at least one of the unit optical elements is different from the height of the concave-convex shape formed by the other unit optical elements.

12. The optical member according to claim 1, 4 or 6; a display element bonded to the optical member.

Images