Light guide plate for image display

Abstract

To provide a light guide plate for image display that can suppress deterioration of a hologram layer.SOLUTION: A light guide plate for image display 8 has: a first laminate 11 sequentially having a first resin substrate 1, a first anchor coat layer 2 and a first barrier layer 3; and a hologram layer 4, in the stated order. The first barrier layer 3 has a thickness of 150 nm or less, and the total thickness of the first anchor coat layer 2 and the first barrier layer 3 is 300 nm or less. The first anchor coat layer 2 shows a tanδ peak temperature of 80°C or lower in a viscoelastic measurement.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light guide plate for image display. [Background technology]

[0002] A light guide plate for image display is sometimes used in a display device. For example, a light guide plate for image display in which a hologram layer is supported on a transparent substrate is used in a display device using VR (Virtual Reality) technology or AR (Augmented Reality) technology. Holograms having various optical functions, such as waveguiding, reflection, and diffraction, are formed in the hologram layer. The hologram material used to form the hologram layer is often a photosensitive composition containing a radical polymerizable monomer, a polyvalent acid, or a base such as an amine, which may deteriorate the resin substrate. It is also known that hologram materials deteriorate due to moisture absorption. Therefore, display devices in which the hologram layer is supported by a resin substrate are prone to deterioration in high-temperature, high-humidity environments.

[0003] Patent Document 1 describes forming a photosensitive material layer that forms a hologram on an optically transparent resin substrate, and covering the photosensitive material layer with an aqueous polymer protective barrier. Patent Document 1 suggests that the aqueous polymer protective barrier is provided for the purpose of resisting attack by moisture. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-181400 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 has the following problems. In the technique described in Patent Document 1, a resin substrate is adhered to the surface of the photosensitive material layer opposite the aqueous polymer protective barrier. Therefore, there is a risk that the photosensitive material will corrode the resin substrate in a high temperature environment. Furthermore, moisture is contained within the resin substrate, and the moisture diffuses into the photosensitive material layer through the contact surface with the photosensitive material layer. In addition, since the substrate is exposed to the outside, moisture continues to permeate the substrate from the outside. As a result, moisture permeates the photosensitive material layer via the resin substrate, and even if the moisture is blocked by the aqueous polymer protective barrier, it is not possible to prevent the photosensitive material layer from deteriorating over time due to moisture from the substrate side.

[0006] An object of the present invention is to provide a light guide plate for image display that can suppress deterioration of a hologram layer. [Means for solving the problem]

[0007] The present inventors have discovered that by providing an anchor coat layer having specific physical properties and a barrier layer between a resin substrate and a hologram layer, and by setting the thickness of the barrier layer and the total thickness of the anchor coat layer and the barrier layer within specific ranges, the barrier properties can be improved and deterioration of the hologram layer can be suppressed, and have completed the present invention. That is, the present invention has the following aspects.

[0008] [1] A light guide plate for image display, comprising a laminate having a resin substrate, an anchor coat layer, and a barrier layer in this order, and a hologram layer, arranged in this order, wherein the thickness of the barrier layer is 150 nm or less, the total thickness of the anchor coat layer and the barrier layer is 300 nm or less, and the tan δ peak temperature in viscoelasticity measurement of the anchor coat layer is 80°C or less. [2] The light guide plate for image display according to [1], wherein the resin substrate contains one or more resins selected from the group consisting of poly(meth)acrylic resins, epoxy resins, cyclic polyolefin resins, and polycarbonate resins. [3] The light guide plate for image display according to [1] or [2], wherein the barrier layer contains an inorganic material. [4] The light guide plate for image display according to any one of [1] to [3], wherein the barrier layer contains one or more inorganic materials selected from the group consisting of silicon oxide, silicon oxynitride, diamond-like carbon, and aluminum oxide. [5] The light guide plate for image display according to any one of [1] to [4], wherein the anchor coat layer contains one or more resins selected from the group consisting of acrylic resins, urethane resins, and polyester resins. [6] The light guide plate for image display according to any one of [1] to [5], wherein the laminate has hard coat layers on both surfaces of the resin substrate. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a light guide plate for image display that can suppress deterioration of the hologram layer. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view showing an example of a light guide plate for image display of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present invention will be described below. However, the present invention is not limited to the embodiment described below, and various modifications are possible without departing from the gist of the present invention.

[0012] <Light guide plate for image display> A light guide plate for image display according to an embodiment of the present invention will be described. The light guide plate for image display of this embodiment includes at least a laminate including a resin substrate, an anchor coat layer, and a barrier layer, and a hologram layer. The resin substrate, anchor coat layer, barrier layer, and hologram layer are arranged in this order in the thickness direction. The resin substrate, anchor coat layer, and barrier layer may be arranged on at least one surface of the hologram layer, but may also be arranged on both surfaces of the hologram layer. When laminates are arranged on both surfaces of the hologram layer, the laminate arranged on one surface of the hologram layer is referred to as the first laminate, and the laminate arranged on the other surface of the hologram layer is referred to as the second laminate. In this case, the hologram layer is sandwiched between the first barrier layer of the first laminate and the second barrier layer of the second laminate, with the first anchor coat layer and the first resin substrate laminated on the other surface of the first barrier layer, and the second anchor coat layer and the second resin substrate laminated on the other surface of the second barrier layer. In this embodiment, the first laminate and the second laminate may be collectively referred to simply as the "laminate" hereinafter. The first resin substrate and the second resin substrate may hereinafter be collectively referred to simply as "resin substrate." The first anchor coat layer and the second anchor coat layer may hereinafter be collectively referred to simply as "anchor coat layer." Furthermore, the first barrier layer and the second barrier layer may hereinafter be collectively referred to simply as "barrier layer."

[0013] One or more transparent layers may be disposed between the resin substrate and the anchor coat layer, between the anchor coat layer and the barrier layer, and between the barrier layer and the hologram layer. Examples of the transparent layer include a hard coat layer. The anchor coat layer, barrier layer, and transparent layer may be disposed on one surface of the resin substrate, but may also be disposed on both surfaces of the resin substrate. That is, the structure may be such that the barrier layer, anchor coat layer, resin substrate, anchor coat layer, barrier layer, and hologram layer are disposed in this order in the thickness direction, or the structure may be such that the barrier layer, anchor coat layer, transparent layer, resin substrate, transparent layer, anchor coat layer, barrier layer, and hologram layer are disposed in this order in the thickness direction.

[0014] The light guide plate for image display has an incident section for receiving image light and a display section for displaying an image based on the image light. The hologram layer is disposed between the incident section and the display section. The hologram layer has a diffraction grating pattern formed thereon for guiding at least the image light incident from the incident section to the display section and emitting it from the display section. The diffraction grating pattern in the display section transmits at least a portion of external light incident from outside the light guide plate for image display. The external light is incident from the surface opposite the display section.

[0015] The image light incident on the incident portion is guided within the hologram layer and then emitted to the outside from the display portion. Meanwhile, external light also passes through the resin substrate and the display portion, so that a viewer of the display portion can observe both the image light and external light within their field of view. The light guide plate for image display of this embodiment is suitable for use in display devices using VR (virtual reality) technology or AR (augmented reality) technology, and is particularly suitable for use in in-vehicle displays and sports sunglasses for outdoor use. Furthermore, the light guide plate for image display of this embodiment may be used not only for displays but also for devices such as a combiner for a head-up display (HUD) mounted on an automobile or a holographic optical element (HOE) represented by a reflector for a reflective liquid crystal display device.

[0016] Hereinafter, a detailed configuration of an example of a light guide plate for image display of this embodiment will be described based on the example shown in Fig. 1. Fig. 1 is a schematic cross-sectional view showing an example of a light guide plate for image display of the embodiment of the present invention.

[0017] In the light guide plate 8 for image display shown in Figure 1, a first resin base material 1, a first anchor coat layer 2, a first barrier layer 3, a hologram layer 4, a second barrier layer 5, a second anchor coat layer 6, and a second resin base material 7 are arranged in this order in the thickness direction. There is no particular limitation on the shape in plan view of the image display light guide plate 8. For example, the image display light guide plate 8 may be shaped so as to be attachable to the display device to be used. For example, the light guide plate 8 for image display may be a rectangular plate larger than the shape to be attached to the display device. In this case, the light guide plate 8 for image display is shaped, for example, by cutting into a shape that can be attached to the display device before being assembled into the display device. The image display light guide plate 8 may be in the form of a flat plate, or may be in the form of a curved plate as required. In the following, an example will be described in which the image display light guide plate 8 is made of a flat plate that is rectangular in plan view.

[0018] <First laminate 11> The first laminate 11 includes, in this order, a first resin substrate 1, a first anchor coat layer 2, and a first barrier layer 3. By disposing the first laminate 11 on the surface of the hologram layer 4, the light guide plate 8 for image display can suppress deterioration of the hologram layer.

[0019] (barrier properties) The water vapor permeability of the first laminate 11 is 0.1 g / m 2 / day is preferred, with 0.08 g / m 2 / day is more preferable, and 0.05 g / m 2 / day is more preferably less than 0.03 g / m 2 / day, and even more preferably less than 0.01 g / m 2 / day is more preferably less than 0.005 g / m 2 Less than / day is even more preferable. When the water vapor transmission rate of the first laminate 11 is within the above range, deterioration of the hologram layer 4 can be further suppressed.

[0020] [First resin base material 1] The first resin base material 1 is disposed at the outermost part in the thickness direction of the light guide plate for image display 8. The first resin base material 1 is disposed on the surface of the light guide plate for image display 8 on the display image output side. The first resin base material 1 has the same shape as the outer shape of the light guide plate 8 for image display. The first resin base material 1 transmits image light emitted from the hologram layer 4 and external light that passes through the second resin base material 7 and the hologram layer 4, which will be described later.

[0021] The thickness of the first resin base material 1 is not particularly limited, but is preferably 0.05 to 10 mm. There is no particular lower limit to the thickness of the first resin base material 1, but from the viewpoint of improving scratch resistance, it is preferably 0.1 mm or more, and more preferably 0.2 mm or more. The upper limit of the thickness of the first resin base material 1 is not particularly limited, but from the viewpoint of improving moldability and total light transmittance, it is preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 2 mm or less. In this specification, the thickness of the first resin base material 1 can be measured by a dial gauge using a stylus, a micrometer, or the like.

[0022] The total light transmittance of the first resin base material 1 is not particularly limited, but is preferably 80% or more, and more preferably 90% or more. If the total light transmittance of the first resin base material 1 is 80% or more, the brightness value of the light guide plate for image display 8 will be better.

[0023] The surface roughness Sa of the first resin base material 1 is not particularly limited, but is preferably 10 nm or less, more preferably 8 nm or less, and even more preferably 6 nm or less, with a lower limit of 0 nm. If the surface roughness Sa is 10 nm or less, the surface roughness Sa of the first laminate 11 can be reduced, and the brightness value of the light guide plate for image display 8 will be improved. In this specification, the surface roughness Sa is the surface roughness measured using a white light interferometer (VertScan, manufactured by Ryoka Systems Co., Ltd.).

[0024] The first resin base material 1 preferably contains a thermoplastic resin from the viewpoint of improving optical properties, impact resistance, scratch resistance, and moldability. Preferred examples of thermoplastic resins include polyolefin resins such as homopolymers or copolymers of ethylene, propylene, butene, etc.; amorphous polyolefin resins such as cyclic polyolefin resins; polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); cellulose resins such as triacetyl cellulose, diacetyl cellulose, and cellophane; polyamide resins such as nylon 6, nylon 66, nylon 12, and copolymer nylon; ethylene-vinyl acetate copolymer partial hydrolyzate (EVOH), polyimide resins, polyetherimide resins, polysulfone resins, and polyethylene terephthalate resins. Examples of suitable thermoplastic resins include organic materials such as tert-butylene sulfone resins, polyether ether ketone resins, polycarbonate resins, polyvinyl butyral resins, polyarylate resins, fluororesins, poly(meth)acrylic resins, styrene resins such as polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, polyvinyl chloride, cellulose, acetyl cellulose, polyvinylidene chloride, polyphenylene sulfide, polyurethane, phenolic resins, epoxy resins, polynorbornene, styrene-isobutylene-styrene block copolymers (SIBS), allyl diglycol carbonate, and biodegradable resins. These thermoplastic resins can be used alone or in combination of two or more. The first resin substrate 1 may also be configured by laminating layers made of two or more materials selected from the group consisting of the above thermoplastic resins. In the present invention, from the viewpoint of transparency, one or more resins selected from the group consisting of poly(meth)acrylic resins, epoxy resins, cyclic polyolefin resins, and polycarbonate resins are preferred. Among these, poly(meth)acrylic resins are preferred because of their excellent scratch resistance and moldability.

[0025] (Poly(meth)acrylic resin) Examples of monomers constituting the poly(meth)acrylic resin include methyl methacrylate, methacrylic acid, acrylic acid, benzyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, Examples thereof include dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, acrylic (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, pentamethylpiperidyl (meth)acrylate, tetramethylpiperidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, etc. These may be used by polymerizing alone or by polymerizing two or more kinds.

[0026] Other monomers copolymerizable with the monomers constituting the poly(meth)acrylic resin may also be added. The other monomers may be monofunctional monomers, i.e., compounds having one polymerizable carbon-carbon double bond in the molecule, or polyfunctional monomers, i.e., compounds having at least two polymerizable carbon-carbon double bonds in the molecule. Examples of monofunctional monomers include aromatic alkenyl compounds such as styrene, α-methylstyrene, and vinyltoluene; alkenyl cyanide compounds such as acrylonitrile and methacrylonitrile; acrylic acid, methacrylic acid, maleic anhydride, and N-substituted maleimides. Examples of polyfunctional monomers include polyunsaturated carboxylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, and trimethylolpropane triacrylate; alkenyl esters of unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate, and allyl cinnamate; polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate, and triallyl isocyanurate; and aromatic polyalkenyl compounds such as divinylbenzene. The monofunctional monomers and polyfunctional monomers can be used alone or in combination of two or more.

[0027] The poly(meth)acrylic resin can be produced by polymerizing the above-mentioned monomer components by a known method such as suspension polymerization, emulsion polymerization, or bulk polymerization.

[0028] [First anchor coat layer 2] The first anchor coat layer 2 is disposed between the first resin substrate 1 and the first barrier layer 3 . By providing the first anchor coat layer 2, the adhesion between the first resin substrate 1 and the first barrier layer 3 is improved, resulting in good barrier properties.

[0029] The first anchor coat layer 2 also functions to relieve residual stress in the first barrier layer 3 and prevent cracks from occurring in the first barrier layer 3 when the first barrier layer 3 described below is formed by dry film deposition. From the viewpoint of sufficiently relaxing the residual stress in the first barrier layer 3, the thickness of the first anchor coat layer 2 is preferably 1 nm or more, more preferably 3 nm or more, and even more preferably 5 nm or more. On the other hand, from the viewpoint of preventing the first barrier layer 3 from being deformed too much due to residual stress, the thickness of the first anchor coat layer 2 is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less.

[0030] When the first resin base material 1 is made of a highly hygroscopic resin such as a poly(meth)acrylic resin, the first resin base material 1 may expand in a humid and hot environment. If the first anchor coat layer 2 and the first barrier layer 3 cannot keep up with this expansion, cracks may occur in the first barrier layer 3, and the barrier properties may deteriorate. In order to be able to follow the expansion of the first resin base material 1 in a humid and hot environment, the tan δ peak temperature in the viscoelasticity measurement of the first anchor coat layer 2 is 80°C or lower, and preferably 75°C or lower. On the other hand, from the viewpoint of preventing the first anchor coat layer 2 from being deformed too much due to the residual stress of the first barrier layer 3, the tan δ peak temperature in the viscoelasticity measurement of the first anchor coat layer 2 is preferably 10°C or higher, more preferably 15°C or higher, and even more preferably 20°C or higher. In this specification, the tanδ peak temperature is the peak temperature of the loss tangent (tanδ) when a sheet having a thickness of 200 μm is prepared from the first anchor coat layer 2 and viscoelasticity measurements are performed using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Measurement and Control Co., Ltd.) under conditions of a frequency of 1 Hz, a heating rate of 3°C / min, and a measurement temperature of -50 to 200°C.

[0031] The total light transmittance of the first anchor coat layer 2 is not particularly limited, but is preferably 80% or more, and more preferably 90% or more. If the total light transmittance of the first anchor coat layer 2 is 80% or more, the brightness value of the light guide plate for image display 8 will be good.

[0032] Furthermore, when the average refractive index of the first resin substrate 1 and the first barrier layer 3 is n1, the refractive index n2 of the first anchor coat layer 2 is preferably within the range of n1±0.20, more preferably within the range of n1±0.15, and even more preferably within the range of n1±0.10. If the refractive index n2 of the first anchor coat layer 2 is within the range of n1±0.20, the luminance value of the light guide plate for image display 8 will be good and color unevenness can be prevented. The refractive index was measured using an Abbe refractometer (NAR-4T, manufactured by Atago Co., Ltd.).

[0033] The material of the first anchor coat layer 2 is not particularly limited, but examples thereof include thermoplastic resins and curable resins. Examples of thermoplastic resins include fluorine-based resins, polyethersulfone-based resins, polycarbonate-based resins, acrylic-based resins, silicone-based resins, cycloolefin-based resins, thermoplastic polyimide-based resins, polyamide-based resins, polyamideimide-based resins, polyarylate-based resins, polysulfone-based resins, polyetherimide-based resins, polyetheretherketone-based resins, polyethersilicone-based resins, polyester-based resins, and polyphenylene sulfide-based resins. Examples of the curable resin include acrylic resin, urethane resin, epoxy resin, and silicone resin. Among these, acrylic resins or polyester resins are preferred as thermoplastic resins from the viewpoint of water vapor barrier properties.

[0034] A silane coupling agent, a sensitizer, a crosslinking agent, an ultraviolet absorber, a polymerization inhibitor, a surfactant, a filler, a release agent, and a thermoplastic resin other than those mentioned above may be added to the resin composition constituting the first anchor coat layer 2. These additives may be used alone or in combination of two or more.

[0035] The first anchor coat layer 2 can be formed, for example, by applying a resin composition for forming the first anchor coat layer 2 to the first resin substrate 1, laminating the first barrier layer 3 thereon, and treating this laminate with a method such as pressing, nip rolling, or thermal lamination. When the first anchor coat layer 2 is made of a curable resin, the formation of the first anchor coat layer 2 may include a curing step.

[0036] [First barrier layer 3] The first barrier layer 3 is disposed between the first anchor coat layer 2 and the hologram layer 4 described below. The first barrier layer 3 prevents gases such as water vapor and oxygen that penetrate from the outside of the light guide plate for image display 8 and from the first resin base material 1 from penetrating into the hologram layer 4 and causing deterioration. Therefore, the smaller the oxygen permeability and water vapor permeability of the first barrier layer 3, the more preferable. The oxygen permeability of the first barrier layer 3 is 1 cm 3 / m 2 / day / atm or less is preferred. The water vapor permeability of the first barrier layer 3 is 1 g / m 2 / day or less is preferable, and 0.5g / m 2 / day or less is more preferable, and 0.1g / m 2 / day or less is even more preferable. Here, the oxygen permeability is measured using an oxygen permeability measuring device (OX-TRAN 2 / 21, manufactured by MOCON), and the water vapor permeability is measured using a water vapor permeability measuring device (DELTAPERM, manufactured by Technolox).

[0037] When the first barrier layer 3 is formed by dry film formation, residual stress may occur that causes the first barrier layer 3 to curl outward. If this residual stress is large, cracks may occur in the first barrier layer 3, deteriorating the barrier properties. In order to prevent the residual stress from becoming too large, the thickness of the first barrier layer 3 is preferably 150 nm or less, and more preferably 130 nm or less. On the other hand, from the viewpoint of improving the barrier property, the thickness of the first barrier layer 3 is preferably 5 nm or more, and more preferably 10 nm or more.

[0038] Furthermore, from the viewpoint of preventing cracks and deformation due to residual stress in the first barrier layer 3, the total thickness of the first anchor coat layer 2 and the first barrier layer is preferably 300 nm or less, more preferably 250 nm or less, and even more preferably 200 nm or less. On the other hand, from the viewpoint of sufficiently alleviating the residual stress with the first anchor coat layer 2 and also improving the barrier properties of the first barrier layer 3, the total thickness of the first anchor coat layer 2 and the first barrier layer is preferably 30 nm or more, and more preferably 50 nm or more.

[0039] The first barrier layer 3 preferably has a higher refractive index than the first resin base material 1. For example, when an acrylic resin is used as the first resin base material 1, the refractive index of the first barrier layer 3 is preferably 1.48 or higher, more preferably 1.48 or higher and 3.0 or lower. If the first barrier layer 3 has a higher refractive index than the first resin base material 1, light passing through the first resin base material 1 via the first barrier layer 3 will be incident on the optically coarse first resin base material 1 from the optically dense first barrier layer 3, and the exit angle of the light from the first barrier layer 3 toward the first resin base material 1 will increase according to the difference in refractive index between the first barrier layer 3 and the first resin base material 1. This enables the field of view (FOV) of the present light guide plate for image display to be widened.

[0040] The first barrier layer 3 preferably contains an inorganic material. Among these, it is more preferable that it contains at least one material selected from the group consisting of silicon oxide, silicon oxynitride, diamond-like carbon (DLC), and aluminum oxide. Furthermore, from the viewpoint of improving the total light transmittance and barrier properties, it is even more preferable that the first barrier layer 3 contains silicon oxide or silicon oxynitride.

[0041] When the first barrier layer 3 is made of silicon oxide or silicon oxynitride, the first barrier layer 3 can be formed by a conventional method such as vacuum deposition, sputtering, ion plating, or plasma CVD. Of these, sputtering is preferred from the viewpoint of obtaining good barrier properties and improving the clarity of the light guide plate 8 for image display. In order to improve the adhesion between the first anchor coat layer 2 and the first barrier layer 3, the surface of the first anchor coat layer 2 may be subjected to a surface treatment such as corona discharge treatment or low-temperature plasma treatment, or may be coated with a silane coupling agent or a mixture of saturated polyester and isocyanate. For example, when forming a film by vacuum deposition, silicon, silicon monoxide, silicon dioxide, silicon nitroxide, or a mixture thereof is used as the evaporation material, and the concentration of the evaporation material is 1.0 × 10 -3 ~2.0×10 -1Under a vacuum of 100 Pa, the material is evaporated by heating using an electron beam, resistance heating, or high-frequency heating. Alternatively, reactive vapor deposition can be employed, which is carried out while supplying oxygen gas and nitrogen gas. In addition, for example, when forming a film by sputtering, silicon, silicon monoxide, silicon dioxide, silicon oxynitride, or a mixture thereof is used as a target, and a concentration of 1.0 × 10 -2 ~5.0×10 -1 Film formation can be performed under a vacuum of 100 Pa. Alternatively, a reactive sputtering method can be employed, which is carried out while supplying oxygen gas, nitrogen gas, or argon gas.

[0042] The silicon oxide or silicon oxynitride forming the first barrier layer 3 may contain calcium, magnesium, or oxides thereof as impurities, as long as the content is 10 mass % or less.

[0043] Diamond-like carbon (DLC) is an amorphous carbon material that generally consists of a ternary structure consisting of a diamond-like structure, a graphite-like structure, and a polyethylene-like polymer structure containing hydrogen atoms. When a hydrocarbon such as ethylene, acetylene, or benzene is used as the carbon source to produce DLC, the resulting structure is basically a ternary structure containing hydrogen. DLC has excellent hardness, lubricity, abrasion resistance, chemical stability, heat resistance, and surface smoothness. Because DLC forms the dense polymer structure described above, it also has excellent gas barrier properties and water vapor barrier properties.

[0044] When the first barrier layer 3 is formed using DLC, any suitable known coating method can be used, such as a physical vapor deposition method such as plasma CVD, ion plating, or ion beam sputtering.

[0045] When the first barrier layer 3 is made of aluminum oxide, the first barrier layer 3 may be made of, for example, Al2O3 only, or may be made of a mixture of two or more selected from the group consisting of Al, AlO, and Al2O3. The atomic ratio of Al:O in the aluminum oxide layer varies depending on the conditions for producing the aluminum oxide layer. The aluminum oxide layer usable as the first barrier layer 3 may contain trace amounts (up to 3% of the total components) of other components as long as the barrier performance is not impaired.

[0046] There are no particular limitations on the method for forming the first barrier layer 3 from aluminum oxide. For example, the first barrier layer 3 may be formed by a PVD method (physical vapor deposition method) such as vacuum deposition, sputtering, or ion plating, or a CVD method (chemical vapor deposition method). For example, in vacuum deposition, Al, Al2O3, etc. are used as deposition source materials, and resistance heating, high-frequency induction heating, electron beam heating, etc. may be used as the deposition source heating method. In vacuum deposition, oxygen, nitrogen, water vapor, etc. may be introduced as a reactive gas, or reactive deposition using ozone addition or ion-assisted means may be used. Furthermore, a bias may be applied to the deposition surface, or the temperature of the deposition surface may be increased or cooled. The same applies to other deposition methods other than sputtering and other vacuum deposition methods, such as PVD and CVD.

[0047] [Configuration of first anchor coat layer 2 and first barrier layer 3] In the first anchor coat layer 2 and the first barrier layer 3 of this embodiment, the thickness of the first barrier layer 3 is 150 nm or less, the total thickness of the first anchor coat layer 2 and the first barrier layer 3 is 300 nm or less, and the tan δ peak temperature in the viscoelasticity measurement of the first anchor coat layer 2 is 80°C or less. If the thickness of the first barrier layer 3 is 150 nm or less, the residual stress of the first barrier layer 3 does not become too large, and therefore the occurrence of cracks in the first barrier layer 3 can be prevented. Furthermore, if the total thickness of the first anchor coat layer 2 and the first barrier layer 3 is 300 nm or less, the first barrier layer 3 can be prevented from being deformed too much due to residual stress. Furthermore, if the tan δ peak temperature in the viscoelasticity measurement of the first anchor coat layer 2 is 80°C or less, even if the first resin base material 1 expands in a humid and hot environment, the first anchor coat layer 2 follows and cracks are less likely to occur. Therefore, by having the above configuration, it is possible to prevent cracks and deformations caused by residual stress in the first barrier layer 3, as well as cracks caused by expansion of the first resin base material 1 in a humid and hot environment, thereby improving the barrier properties and suppressing deterioration of the hologram layer.

[0048] [Hologram layer 4] The hologram layer 4 is disposed on the surface of the first barrier layer 3 opposite to the surface to which the first anchor coat layer 2 is adhered. The hologram layer 4 has a diffraction grating appropriately formed thereon that corresponds to the function that the light guide plate 8 for image display should have.

[0049] The material of the hologram layer 4 is not particularly limited, and any known resin material for forming a hologram can be used. Examples of materials for the hologram layer 4 include hologram recording materials consisting of a solvent-soluble thermosetting resin having at least one cationic polymerizable ethylene oxide ring in its structural unit and a radically polymerizable ethylenic monomer (see JP-A-9-62169, JP-A-11-161141, and JP-A-2002-310932). Specifically, the hologram layer 4 is preferably formed from a photosensitive material containing an epoxy resin such as a bisphenol-based epoxy resin; a (meth)acrylate such as triethylene glycol diacrylate; a photopolymerization initiator such as 4,4'-bis(tert-butylphenyl)iodonium hexafluorophosphate; a wavelength sensitizer such as 3,3'-carbonylbis(7-diethylamino)coumarin; and an organic solvent such as 2-butanone.

[0050] <Second laminate 12> The second laminate 12 includes, in this order, a second barrier layer 5, a second anchor coat layer 6, and a second resin base material 7. By disposing the second laminate 12 on the surface of the hologram layer 4 opposite to the surface facing the first laminate 11, the light guide plate 8 for image display can further suppress deterioration of the hologram layer 4.

[0051] (barrier properties) The water vapor permeability of the second laminate 12 is 0.1 g / m 2 / day is preferred, with 0.08 g / m 2 / day is more preferable, and 0.05 g / m 2 / day is more preferably less than 0.03 g / m 2 / day, and even more preferably less than 0.01 g / m 2 / day is more preferably less than 0.005 g / m 2 Less than / day is even more preferable. When the water vapor transmission rate of the second laminate 12 is within the above range, deterioration of the hologram layer 4 can be further suppressed.

[0052] [Second barrier layer 5] The second barrier layer 5 is laminated on the opposite side of the first barrier layer 3 with the hologram layer 4 interposed therebetween. The second barrier layer 5 has the same structure as that exemplified in the description of the first barrier layer 3. However, the thickness, material, etc. of the second barrier layer 5 may be different from those of the first barrier layer 3.

[0053] [Second anchor coat layer 6] The second anchor coat layer 6 is disposed between the second barrier layer 5 and the second resin substrate 7. The second anchor coat layer 6 has a configuration similar to that exemplified in the description of the first anchor coat layer 2. However, the thickness, material, etc. of the second anchor coat layer 6 may be different from those of the first anchor coat layer 2.

[0054] [Second resin base material 7] The second resin base material 7 is laminated on the surface of the second barrier layer 5. The second resin base material 7 has the same configuration as that exemplified in the description of the first resin base material 1. However, the thickness, material, etc. of the second resin base material 7 may be different from those of the first resin base material 1. In particular, since the second resin base material 7 is disposed on the surface of the external light incident side, which is located opposite the display image output side of the light guide plate 8 for image display, a material having a higher surface hardness than the first resin base material 1 may be used.

[0055] [Light guide plate for image display 8] In the light guide plate 8 for image display, a first anchor coat layer 2 and a first barrier layer 3, and a second barrier layer 5 and a second anchor coat layer 6 are arranged between the first resin substrate 1 and the hologram layer 4, and between the second resin substrate 7 and the hologram layer 4, respectively. Gases outside the light guide plate 8 for image display pass through the first resin base material 1 and the second resin base material 7 to some extent and accumulate inside. At this time, moisture in particular tends to accumulate in the first resin base material 1 and the second resin base material 7. However, according to the configuration of this embodiment, moisture that has penetrated into the first resin base material 1 and the second resin base material 7 from the outside can be blocked by the first barrier layer 3 and the second barrier layer 5, thereby suppressing the penetration of water vapor into the hologram layer 4 and preventing deterioration of the hologram layer 4.

[0056] Furthermore, the chemical resistance of the first resin base material 1 and the second resin base material 7 is significantly lower than that of glass, although the degree of resistance varies depending on the type of resin material, and therefore the first resin base material 1 and the second resin base material 7 have lower solvent resistance and hologram material resistance than glass. When the first resin substrate 1 and the second resin substrate 7 are in contact with the hologram layer 4, the hologram agent, which is a component of the hologram layer 4, is likely to pass through the first resin substrate 1 and the second resin substrate 7, or to accumulate inside the first resin substrate 1 and the second resin substrate 7. When the first resin substrate 1 and the second resin substrate 7 are exposed to the hologram agent, the first resin substrate 1 and the second resin substrate 7 deteriorate, and a decrease in FOV (Field of View) and a decrease in clarity are likely to occur. However, according to the configuration of this embodiment, by providing the first barrier layer 3 and the second barrier layer 5 between the first resin base material 1 and the hologram layer 4 and the second resin base material 7, respectively, the penetration of the hologram agent into the first resin base material 1 and the second resin base material 7 is suppressed, and deterioration of the first resin base material 1 can also be prevented.

[0057] [Hard coat layer] The light guide plate for image display of this embodiment may have a hard coat layer on one or both surfaces of the first resin substrate for the purpose of increasing the pencil hardness of the surface of the first resin substrate or for the purpose of reducing the surface roughness Sa of the first barrier layer.

[0058] The hard coat layer is preferably formed from a curable resin composition. The curable resin composition is not particularly limited as long as it is cured by irradiation with energy rays such as electron beams, radioactive rays, or ultraviolet rays, or by heating. However, from the viewpoints of molding time and productivity, an ultraviolet-curable resin composition is preferred.

[0059] Preferred examples of the curable resin constituting the curable resin composition include acrylate compounds, urethane acrylate compounds, epoxy acrylate compounds, carboxyl group-modified epoxy acrylate compounds, polyester acrylate compounds, copolymeric acrylates, alicyclic epoxy resins, glycidyl ether epoxy resins, vinyl ether compounds, and oxetane compounds. These curable resins can be used alone or in combination of two or more. Among these, examples of curable resins that impart excellent surface hardness include radical polymerization type curable compounds such as polyfunctional acrylate compounds, polyfunctional urethane acrylate compounds, and polyfunctional epoxy acrylate compounds, and thermal polymerization type curable compounds such as alkoxysilanes and alkylalkoxysilanes.

[0060] The curable resin composition forming the hard coat layer may contain a leveling agent as a surface conditioning component. Examples of the leveling agent include a fluorine-based leveling agent, a silicone-based leveling agent, and an acrylic-based leveling agent. Among these, an acrylic-based leveling agent is preferred as the leveling agent because it can ensure excellent adhesion when the first barrier layer is laminated on the surface of the hard coat layer.

[0061] When the curable resin composition is cured by ultraviolet light, a photopolymerization initiator is used. Examples of the photopolymerization initiator include benzil, benzophenone and its derivatives, thioxanthones, benzil dimethyl ketals, α-hydroxyalkylphenones, hydroxyketones, aminoalkylphenones, and acylphosphine oxides. The amount of the photopolymerization initiator added is generally 0.1 to 8 parts by mass per 100 parts by mass of the curable resin composition.

[0062] The curable resin composition forming the hard coat layer may contain a refractive index adjusting component. Examples of the refractive index adjusting component include fine particles of a high refractive index metal compound such as zinc oxide, zirconium oxide, or titanium oxide, and fine particles of a low refractive index metal compound such as magnesium fluoride. The size of the fine particles is preferably 5 to 50 nm, since this does not impair the transparency or total light transmittance of the hard coat layer. Alternatively, the fine particles of such a refractive index adjusting component may be premixed with a curable resin composition and then mixed with the curable resin composition forming the hard coat layer. Alternatively, the fine particles of the refractive index adjusting component may be premixed with a curable resin composition and then directly used as the curable resin composition forming the hard coat layer. Premixed fine particles of the refractive index adjusting component with a curable resin composition are commercially available. Examples of such commercially available products include Lioduras TYZ, Lioduras TYT, and Lioduras TYM (all manufactured by Toyochem Co., Ltd.).

[0063] In addition to the above-mentioned components, the curable resin composition for forming the hard coat layer may contain additives such as lubricants such as silicon-based compounds, fluorine-based compounds, or mixtures thereof, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants such as silicone-based compounds, fillers, glass fibers, silica, etc. These additives may be used alone or in combination of two or more.

[0064] The thickness of the hard coat layer is not particularly limited, but is preferably 1 to 20 μm. If the thickness of the hard coat layer is 1 μm or more, sufficient hardness can be imparted to the surface of the first resin substrate 1. If the thickness of the hard coat layer is 20 μm or less, moldability and cuttability of the first resin substrate 1 can be ensured. Furthermore, it is also preferable in that cure shrinkage of the hard coat layer is suppressed, preventing warping and undulation of the first resin substrate 1.

[0065] When the refractive index of the first resin base material 1 is na, the refractive index nb of the hard coat layer is preferably within the range of na±0.20, more preferably within the range of na±0.15, and even more preferably within the range of na±0.10. If the refractive index nb of the hard coat layer is within the range of na±0.20, the luminance value of the light guide plate for image display 8 can be improved and color unevenness can be prevented.

[0066] Examples of methods for forming the hard coat layer include, but are not limited to, a method in which a curable resin composition is applied as a coating material to the surface of the first resin substrate 1, and then a cured film is formed and laminated on the surface of the first resin substrate 1. A known method is used as a lamination method for the first resin substrate 1. Examples of known methods include dip coating, natural coating, reverse coating, comma coater, roll coating, spin coating, wire bar coating, extrusion, curtain coating, spray coating, and gravure coating. Alternatively, for example, a method may be employed in which a hard coat layer is laminated on the first resin substrate 1 using a transfer sheet having a release layer on which a hard coat layer is formed. In order to improve the adhesion between the hard coat layer and the first resin base material 1, a base film (primer layer) may be provided on the surface of the first resin base material 1 in advance.

[0067] <Method of manufacturing a light guide plate for image display> As an example of a method for manufacturing a light guide plate for image display of this embodiment, a method for manufacturing a light guide plate for image display 8 shown in FIG. 1 will be described. A first resin substrate 1 and a second resin substrate 7 are prepared ([Substrate preparation step]), and a first barrier layer 3 and a second barrier layer 5 are formed on the surfaces of the first resin substrate 1 and the second resin substrate 7 via a first anchor coat layer 2 and a second anchor coat layer 6, respectively ([Barrier layer formation step]). As a method for manufacturing the first barrier layer 3 and the second barrier layer 5, an appropriate manufacturing method is selected depending on the materials of the first barrier layer 3 and the second barrier layer 5. For example, a photosensitive material for forming a hologram is applied to the surface of the first barrier layer 3 formed on the first resin substrate 1. At this time, a transparent sealing layer having the same thickness as the hologram layer 4 may be provided on the outer periphery of the first barrier layer 3. The sealing layer seals the outer periphery of the hologram layer 4 after the hologram layer 4 is formed from the photosensitive material. The sealing layer is made of a transparent material, such as an epoxy resin, a silicone resin, or an enethiol resin. Thereafter, the second resin substrate 7 on which the second barrier layer 5 has been formed is placed on the photosensitive material with the second barrier layer 5 facing the photosensitive material ([Light guide plate manufacturing process]). However, the above-described manufacturing order is an example. For example, a photosensitive material may be applied to the second resin base material 7 on which the second barrier layer 5 is formed, and then the first resin base material 1 on which the first barrier layer 3 is formed may be placed on the hologram layer 4. Thereafter, the first resin substrate 1, the first anchor coat layer 2, the first barrier layer 3, the hologram layer 4, the second barrier layer 5, the second anchor coat layer 6 and the second resin substrate 7 are bonded together by a reduced pressure press to obtain a light guide plate 8 for image display. Thereafter, interference fringes corresponding to the diffraction pattern are formed on the photosensitive material, forming a diffraction grating in the photosensitive material. [Example]

[0068] The present invention will be described in more detail below with reference to examples and production examples. However, the present invention is not limited to the examples and production examples described below, and various modifications are possible without departing from the gist of the present invention.

[0069] Example 1 The resin substrate is made of PMMA (polymethyl methacrylate, trade name "Acrylite (registered trademark), manufactured by Mitsubishi Chemical Corporation). The resin substrate is a rectangular plate with a width of 200 mm, a length of 200 mm, and a thickness of 1 mm. The material of the hard coat layer is an acrylic UV-curable resin (product name "Shikou UV1700B", manufactured by Mitsubishi Chemical Corporation). The anchor coat layer is made of anchor coat solution 1 (referred to as "AC-1" in Table 1, tan δ peak temperature: 20°C) which is a mixture of amorphous polyester resin and isocyanate compound in a mass ratio of 10:1. The barrier layer is made of silicon oxynitride.

[0070] Using the above materials, a laminate is produced by carrying out the substrate preparation step and barrier layer formation step described below.

[0071] [Base material preparation process] In the substrate preparation step, the resin substrate is washed and dried, and then a hard coat layer is formed on the resin substrate. The resin substrate is cut into a 200 mm x 200 mm rectangle and ultrasonically cleaned for 5 minutes while immersed in a 5% aqueous surfactant solution of a neutral detergent (product name "Semiclean (registered trademark) M-LO", manufactured by Yokohama Oil & Fat Industries Co., Ltd.). The resin substrate is then ultrasonically cleaned for 5 minutes while immersed in ultrapure water. The resin substrate is then rinsed with ultrapure water, air-dried, and then dried in a nitrogen atmosphere in an oven at 80°C. The air-dried evaluation sample is then UV-ozone cleaned for 1 minute in a UV-ozone cleaner. Next, an acrylic UV-curable resin, which is the material for the hard coat layer, is applied to both surfaces of the resin substrate using a bar coater, dried at 90°C for 1 minute, and then exposed to an integrated light intensity of 500 mJ / cm 2 Both surfaces are exposed to light with a 5 μm thick hard coat layer.

[0072] [Barrier layer formation process] In the barrier layer forming step, a barrier layer is formed on the surface of the hard coat layer via an anchor coat layer. Anchor coating solution 1 is applied to the surface of the hard coating layer using a bar coater and dried at 60° C. for 1 minute to provide an anchor coating layer with a thickness of 25 nm. A silicon oxynitride film having a thickness of 130 nm is formed by reactive sputtering using silicon (manufactured by Kojundo Chemical Laboratory Co., Ltd.) as a target under the conditions shown in Table 1 while supplying oxygen gas, nitrogen gas, and argon gas. By the above operations, a laminate of Example 1 consisting of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-1, 25 nm) / barrier layer (silicon oxynitride, 130 nm) is obtained.

[0073] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Example 1.

[0074] <Example 2> In Example 2, a laminate was produced in the same manner as in Example 1, except that the thickness of the anchor coat layer, the thickness of the barrier layer, and the film-forming conditions were changed as shown in Table 1. That is, the laminate of Example 2 consists of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-1, 100 nm) / barrier layer (silicon oxynitride, 50 nm).

[0075] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Example 2.

[0076] Example 3 In Example 3, the material for the anchor coat layer was anchor coat solution 2 (referred to as "AC-2" in Table 1, tan δ peak temperature: 56°C), which was a mixture of an acrylic resin and an isocyanate compound in a mass ratio of 10:1, and a laminate was produced in the same manner as in Example 1, except that the thickness of the anchor coat layer, the thickness of the barrier layer, and the film-forming conditions were changed as shown in Table 1. That is, the laminate of Example 3 consists of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-2, 100 nm) / barrier layer (silicon oxynitride, 100 nm).

[0077] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Example 3.

[0078] Example 4 In Example 4, a laminate was produced in the same manner as in Example 3, except that the thickness of the anchor coat layer, the thickness of the barrier layer, and the film-forming conditions were changed as shown in Table 1. That is, the laminate of Example 4 consists of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-2, 50 nm) / barrier layer (silicon oxynitride, 20 nm).

[0079] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Example 4.

[0080] <Example 5> In Example 5, the material for the anchor coat layer was anchor coat solution 3 (referred to as "AC-3" in Table 1, tan δ peak temperature: 72°C), which was a mixture of an acrylic resin and an isocyanate compound in a mass ratio of 10:1, and a laminate was produced in the same manner as in Example 1, except that the thickness of the anchor coat layer, the thickness of the barrier layer, and the film-forming conditions were changed as shown in Table 1. That is, the laminate of Example 5 consists of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-3, 100 nm) / barrier layer (silicon oxynitride, 100 nm).

[0081] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Example 5.

[0082] Example 6 In Example 6, a laminate was produced in the same manner as in Example 5, except that the thickness of the anchor coat layer, the thickness of the barrier layer, and the film-forming conditions were changed as shown in Table 1. That is, the laminate of Example 6 consists of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-3, 50 nm) / barrier layer (silicon oxynitride, 70 nm).

[0083] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Example 6.

[0084] <Comparative Example 1> In Comparative Example 1, a laminate was produced in the same manner as in Example 1, except that the thickness of the anchor coat layer was changed as shown in Table 1. That is, the laminate of Comparative Example 1 consisted of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-1, 200 nm) / barrier layer (silicon oxynitride, 130 nm).

[0085] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Comparative Example 1.

[0086] <Comparative Example 2> In Comparative Example 2, a laminate was produced in the same manner as in Example 4, except that the thickness of the barrier layer was changed as shown in Table 1. That is, the laminate of Comparative Example 2 consisted of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-3, 100 nm) / barrier layer (silicon oxynitride, 160 nm).

[0087] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Comparative Example 2.

[0088] <Comparative Example 3> In Comparative Example 3, the material for the anchor coat layer was anchor coat solution 4 (referred to as "AC-4" in Table 1, tan δ peak temperature: 82°C), which was a mixture of an acrylic resin and an isocyanate compound in a mass ratio of 10:1, and a laminate was prepared in the same manner as in Example 1, except that the thickness of the anchor coat layer, the thickness of the barrier layer, and the film-forming conditions were changed as shown in Table 1. That is, the laminate of Comparative Example 3 consisted of hard coat layer / resin substrate / hard coat layer / anchor coat layer (AC-4, 100 nm) / barrier layer (silicon oxynitride, 100 nm).

[0089] Table 1 shows the material of the resin substrate, the material of the hard coat layer, the material and thickness of the anchor coat layer, the material of the barrier layer, the deposition pressure of the barrier layer, the power during deposition, the flow rates of Ar, O2, and N2, and the thickness of the barrier layer for the laminate of Comparative Example 3.

[0090] <Measurement and evaluation methods> The methods for measuring and evaluating various physical properties of the laminates obtained in the examples and comparative examples will be described below.

[0091] (tanδ peak temperature) Anchor coating solutions 1 to 4 of the examples and comparative examples were dried at 80° C. to prepare sheets with a thickness of 200 μm. The prepared sheet is subjected to viscoelasticity measurement using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Measurement Control Co., Ltd.) under conditions of a frequency of 1 Hz, a heating rate of 3°C / min, and a measurement temperature of -50 to 200°C, and the peak temperature [°C] of the loss tangent (tanδ) is determined.

[0092] In the "tan δ peak temperature [°C]" column of "anchor coat layer" in Table 1, the measured value of the peak temperature [°C] of the loss tangent (tan δ) is shown.

[0093] (Appearance evaluation) The appearance of the laminates of the Examples and Comparative Examples was observed immediately after the barrier layer was formed in the barrier layer forming step, and evaluated according to the following criteria. Furthermore, the laminates of the examples and comparative examples were placed in a thermo-hygrostat set at a temperature of 40°C and a relative humidity of 90%RH, and after one day, the appearance was observed and again evaluated according to the following criteria. ◯ (good): No cracks are observed on the barrier layer surface. × (poor): Cracks were generated on the surface of the barrier layer.

[0094] The columns "Immediately after film formation" and "After 1 day at 40°C and 90%RH" under "Appearance evaluation" in Table 1 show the appearance evaluation immediately after the barrier layer was formed and the appearance evaluation after the laminate was placed in a thermo-hygrostat set at a temperature of 40°C and a relative humidity of 90%RH and left for 1 day, respectively.

[0095] (Water vapor barrier properties) Using a water vapor transmission rate measuring device (DELTAPERM, manufactured by Technolox), the laminates of the examples and comparative examples were set so that the first barrier layer side faced the detector side (the first resin substrate side faced the water vapor exposure side), and the water vapor transmission rate [g / m2 / day] was measured under conditions of a temperature of 40°C and a relative humidity of 90%RH.

[0096] Table 1 "Water vapor transmission rate [g / m 2 / day] column shows the measured water vapor transmission rate.

[0097] [Table 1]

[0098] <Explanation of results> In the laminates of Examples 1 to 6, the thickness of the barrier layer is 150 nm or less, the total thickness of the anchor coat layer and barrier layer is 300 nm or less, and the tan δ peak temperature in the viscoelasticity measurement of the anchor coat layer is 80° C. or less. Since the thickness of the barrier layer and the total thickness of the anchor coat layer and the barrier layer are within the above ranges, these laminates are less likely to develop cracks or deformations due to residual stress caused by the formation of the barrier layer, and therefore have a good appearance immediately after formation. Furthermore, since the tan δ peak temperature in the viscoelasticity measurement of the anchor coat layer of these laminates is within the above range, cracks caused by expansion of the resin substrate in a humid and hot environment are less likely to occur, and the appearance is also good even after one day at 40°C and 90% humidity.

[0099] <Production Example 1> An example of manufacturing a light guide plate 8 for image display using the laminate of Example 1 will be described below. The photosensitive material used to form the hologram layer 4 is a mixture of 100 parts by mass of bisphenol-based epoxy resin jER (registered trademark) 1007 (manufactured by Mitsubishi Chemical Corporation, degree of polymerization n=10.8, epoxy equivalent: 1750 to 2200), 50 parts by mass of triethylene glycol diacrylate, 5 parts by mass of 4,4'-bis(tert-butylphenyl)iodonium hexafluorophosphate, and 0.5 parts by mass of 3,3'-carbonylbis(7-diethylamino)coumarin in 100 parts by mass of 2-butanone (hereinafter also referred to as "photosensitive material A").

[0100] (Light guide plate manufacturing process) In the light guide plate manufacturing process of Manufacturing Example 1, a light guide plate 8 for image display is manufactured using two sheets of the laminate of Example 1. A sealing layer having a width of 5 mm and a thickness of 5 μm is applied to the periphery of the barrier layer of one of the laminates. The sealing layer is made of a transparent material and is not particularly limited as long as it is a material that can bond the barrier layers of the laminate to each other, but in Production Example 1, an optical adhesive (manufactured by Denka Company, product name "Hardlock (registered trademark) OP-1045K") is used. As a result, an intermediate body with a stepped seal layer is formed, the opening of which is surrounded by the seal layer and has a size of 50 mm x 50 mm. Thereafter, the photosensitive material A for forming the hologram layer 4 is applied onto this intermediate body by spin coating. The photosensitive material A is applied so that the thickness after drying is 5 μm. Thereafter, the other laminate is laminated on the hologram layer 4 via the seal layer so that its barrier layer faces the barrier layer of the stepped seal layer intermediate, and press-laminated under reduced pressure under the conditions of an absolute pressure of 5 kPa, a temperature of 70°C, and a press pressure of 0.04 MPa. After this, a diffraction grating is recorded in the press-bonded hologram layer 4. During this process, the temperature of the laminate including the hologram layer 4 is maintained at 20°C. The diffraction grating is formed by irradiating the laminate with two laser beams and adjusting the irradiation angle and intensity of each beam to form interference fringes so that the required diffraction pattern is formed. In this way, the diffraction grating is recorded in the hologram layer 4. This diffraction grating is a color display diffraction grating that diffracts light in the red, green, and blue wavelength regions that is incident as image light on the incident portion and outputs it from the display portion at positions corresponding to the pixels of the image light. Thereafter, while the laminate including the hologram layer 4 was kept at 20° C., ultraviolet light (wavelength 365 nm, irradiance 80 W / cm ) was irradiated from one side of the laminate. 2 ) is irradiated over the entire surface for 30 seconds. A high-pressure mercury lamp is used as the source of ultraviolet light. As a result, the sealing layer is hardened, and the light guide plate 8 for image display of Production Example 1 is produced. [Industrial Applicability]

[0101] A light guide plate for image display using the light guide plate substrate of the present invention is useful, for example, for use as a display device for VR and AR applications, such as a head-up display, a wearable display, or a head-mounted display. [Explanation of symbols]

[0102] 1 First resin base material 2 First anchor coat layer 3 First barrier layer 4 Hologram Layer 5 Second barrier layer 6 Second anchor coat layer 7 Second resin base material 8 Light guide plate for image display 11 First laminate 12 Second laminate

Claims

1. A light guide plate for displaying images, comprising a laminate having a resin substrate, an anchor coat layer, and a barrier layer in that order, and a hologram layer arranged in that order, wherein the anchor coat layer contains an acrylic resin, the thickness of the anchor coat layer is 100 nm or less, the thickness of the barrier layer is 130 nm or less, the total thickness of the anchor coat layer and the barrier layer is 200 nm or less, and the water vapor transmittance of the laminate is less than 0.1 g / m² / day.

2. The image display light guide plate according to claim 1, wherein the resin substrate comprises one or more resins selected from the group consisting of poly(meth)acrylic resins, epoxy resins, cyclic polyolefin resins, and polycarbonate resins.

3. The image display light guide plate according to claim 1 or 2, wherein the barrier layer includes an inorganic material.

4. The image display light guide plate according to any one of claims 1 to 3, wherein the barrier layer comprises one or more inorganic materials selected from the group consisting of silicon oxide, silicon oxynitride, diamond-like carbon, and aluminum oxide.

5. The image display light guide plate according to any one of claims 1 to 4, wherein the laminate has hard coat layers on both surfaces of the resin substrate.

Images