Optical laminates and display systems for near-eye devices

Abstract

To provide an optical laminate applicable to near-eye devices that can cut out unwanted light. [Solution] An optical laminate according to an embodiment of the present invention comprises an IR absorption layer and a functional member, wherein the light transmittance of the IR absorption layer at 940 nm is 60% or less. The optical laminate may also include a polarizing member, a first phase difference member, and a protective member as the functional member.

Description

Technical Field

[0001] The present invention relates to an optical laminate for a near-eye device and a display system.

Background Art

[0002] Image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (e.g., organic EL display devices) have been rapidly spreading. In image display devices, in order to realize image display and improve the performance of image display, generally, optical members such as polarizing members and retardation members are used (see, for example, Patent Document 1).

[0003] In recent years, new applications of image display devices have been developed. For example, near-eye devices such as display goggles (VR goggles) for realizing Virtual Reality (VR) have begun to be commercialized. A near-eye device is characterized in that the distance between a person's eye and a display is short. In such a device, there is concern about an adverse effect on the eye caused by unnecessary light emitted from the display. For example, a disease of the eye (e.g., cataract) caused by infrared light emitted from an OLED panel may become a problem.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The main object of the present invention is to provide an optical laminate applicable to a near-eye device, which can cut unnecessary light.

Means for Solving the Problems

[0006] 1. An optical laminate according to an embodiment of the present invention is for a near-eye device and comprises an IR absorption layer and a functional member, wherein the light transmittance of the IR absorption layer at 940 nm is 60% or less. 2. The optical laminate described in item 1 above may include a polarizing member, a first phase difference member, and a protective member as the functional members. 3. In the optical laminate described in 1 or 2 above, the light transmittance A1 of the IR absorption layer at 900 nm may be 90% or less of the light transmittance B1 of the functional member at 900 nm. 4. In the optical laminate described in any of items 1 to 3 above, the light transmittance A2 of the IR absorption layer at 550 nm may be 90% or more of the light transmittance B2 of the functional member at 550 nm. 5. The optical laminate described in any of items 1 to 4 above may have a ratio (A2 / A1) of the light transmittance A2 of the IR absorption layer at 550 nm to the light transmittance A1 of the IR absorption layer at 900 nm of 1.4 or more. 6. The optical laminate described in any of items 1 to 5 above may have a light transmittance A2 of the IR absorption layer at 550 nm of 80% or more. 7. The display system according to an embodiment of the present invention comprises a display element, the optical laminate, and a lens portion in this order. [Effects of the Invention]

[0007] According to embodiments of the present invention, it is possible to provide an optical laminate applicable to a near-eye device that can cut out unwanted light. [Brief explanation of the drawing]

[0008] [Figure 1A] This is a schematic cross-sectional view of an optical laminate according to an embodiment of the present invention. [Figure 1B] This is a schematic cross-sectional view of an optical laminate according to an embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of an optical laminate according to an embodiment of the present invention. [Figure 3]This is a schematic diagram showing the general configuration of a display system including an optical laminate according to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc., of each part compared to the embodiments, but these are merely examples and do not limit the interpretation of the present invention. Also, in this specification, "~" indicating a numerical range includes its upper and lower limits.

[0010] (Definitions of terms and symbols) The definitions of terms and symbols used in this specification are as follows: (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction where the refractive index is maximum in the plane (i.e., the slow phase axis direction), "ny" is the refractive index in the direction perpendicular to the slow phase axis in the plane (i.e., the fast phase axis direction), and "nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane phase difference measured with light of wavelength λnm at 23°C. For example, "Re(550)" is the in-plane phase difference measured with light of wavelength 550nm at 23°C. Re(λ) can be calculated using the formula: Re(λ) = (nx - ny) × d, where d (nm) is the thickness of the layer (film). (3) Phase difference in the thickness direction (Rth) "Rth(λ)" is the phase difference in the thickness direction measured with light of wavelength λnm at 23°C. For example, "Rth(550)" is the phase difference in the thickness direction measured with light of wavelength 550nm at 23°C. Rth(λ) can be calculated using the formula: Rth(λ) = (nx - nz) × d, where d (nm) is the thickness of the layer (film). (4) Nz coefficient The Nz coefficient is calculated using the formula Nz = Rth / Re. (5)Angle In this specification, when an angle is referred to, the angle includes both clockwise and counterclockwise directions with respect to the reference direction. Therefore, for example, "45°" means 45° clockwise or counterclockwise. Also in this specification, "approximately parallel" includes cases within the range of 0°±10°, for example, within the range of 0°±5°, preferably 0°±3°, more preferably 0°±1°, and "approximately orthogonal" includes cases within the range of 90°±10°, for example, within the range of 90°±5°, preferably 90°±3°, more preferably 90°±1°.

[0011] A. Optical laminate An optical laminate for a near-eye device according to an embodiment of the present invention comprises an IR absorption layer and a functional member. The IR absorption layer has a light transmittance of 60% or less at 940 nm. The optical laminate according to an embodiment of the present invention is applicable to a near-eye device. A near-eye device refers to a device with a short viewing distance from the display element, such as VR goggles or smart glasses. The viewing distance may be, for example, within 50 mm (preferably 20 to 30 mm). Therefore, the optical laminate for a near-eye device can be installed within 50 mm of the device user's eye. In this specification, "functional member" is a general term for members constituting the optical laminate other than the IR absorption layer. The functional member may be one layer or two or more layers. Examples of functional members include a polarizing member, a phase difference member, a protective member, and an adhesive member (adhesive layer).

[0012] FIG. 1A and FIG. 1B are schematic cross-sectional views of an optical laminate according to an embodiment of the present invention. The optical laminates 100a and 100b include an IR absorption layer 40, and a polarizing member 10, a first retardation member 20, and a protective member 30 as functional members. In one embodiment, the polarizing member 10, the first retardation member 20, and the protective member 30 are arranged in this order. The arrangement position of the IR absorption layer 40 can be any appropriate position. In one embodiment, as shown in FIG. 1A, the IR absorption layer 40 can be arranged between the first retardation member 20 and the protective member 30. For example, the IR absorption layer 40 is arranged adjacent to the protective member 30 (preferably, directly arranged without intervening another layer). In another embodiment, as shown in FIG. 1B, the IR absorption layer 40 is arranged between the polarizing member 10 and the retardation member 20. For example, the IR absorption layer 40 is arranged adjacent to the first retardation member 20. The optical laminate can include any other appropriate layer as needed. For example, the optical laminate may include an adhesive layer, and each functional member can be laminated via the adhesive layer (not shown). Also, the optical laminate may include a member (so-called, positive C plate) having a refractive index characteristic showing a relationship of nz > nx = ny.

[0013] In one embodiment, the IR absorption layer is arranged adjacent to the first retardation member 20 (preferably, directly arranged without intervening another layer). A material having excellent heat resistance can be used for the first retardation member, and if the IR absorption layer is formed on the first retardation member, it is possible to prevent a change in the characteristics of the functional member due to heating during formation.

[0014] (IR absorption layer) As described above, the IR absorption layer has a light transmittance at 940 nm of 60% or less. By providing such an IR absorption layer, it is possible to reduce the adverse effects of the light emitted from the display element on the user's eyes. For example, it is possible to prevent cataracts caused by infrared light emitted from the display element. Further, if the above optical laminate is applied to a predetermined device, it is possible to suppress the influence of stray light generated in the device, and as a result, various sensors can function with high precision. Such an optical laminate that exhibits such an effect is particularly useful when the device includes a member having a high light reflectivity such as an OLED panel. The light transmittance of the IR absorption layer at 940 nm is preferably 55% or less, more preferably 50% or less, still more preferably 45% or less, and particularly preferably 40% or less. If it is within such a range, the above effect becomes remarkable. The lower limit of the light transmittance of the IR absorption layer at 940 nm is, for example, 10% (preferably 5%, more preferably 3%).

[0015] The light transmittance A1 of the IR absorption layer at 900 nm is preferably 65% or less, more preferably 60% or less, still more preferably 50% or less, and particularly preferably 45% or less. If it is within such a range, the effect of the present invention becomes remarkable. The lower limit of the light transmittance A1 of the IR absorption layer at 900 nm is, for example, 10% (preferably 5%, more preferably 3%).

[0016] The light transmittance A2 of the IR absorption layer at 550 nm is preferably 80% or more, more preferably 82% or more, still more preferably 84% or more, and particularly preferably 86% or more. If it is within such a range, the visibility of the device to which the above optical laminate is applied can be improved. The upper limit of the light transmittance A2 of the IR absorption layer at 550 nm is, for example, 98%.

[0017] The ratio of the light transmittance A2 at 550 nm to the light transmittance A1 at 900 nm of the IR absorption layer (A2 / A1) is preferably 1.4 or higher, more preferably 1.5 or higher, even more preferably 2 or higher, and particularly preferably 3 or higher. Within this range, it is possible to provide an optical laminate that cuts out unwanted light that adversely affects the eyes without impairing visibility. The upper limit of A2 / A1 is, for example, 15.

[0018] The light transmittance A1 of the IR absorption layer at 900 nm is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less, compared to the light transmittance B1 of the functional member at 900 nm. Within this range, the effects of the present invention are remarkable. Furthermore, the light transmittance A1 of the IR absorption layer at 900 nm may be 10% or more, or 5% or more, compared to the light transmittance B1 of the functional member at 900 nm. In this specification, the light transmittance of the functional member corresponds to the light transmittance of a sample obtained by removing the IR layer from the optical laminate.

[0019] The light transmittance A2 of the IR absorption layer at 550 nm is preferably 90% or more, more preferably 92% or more, and even more preferably 95% or more, compared to the light transmittance B2 of the functional member at 550 nm. Within this range, an optical laminate that does not impair visibility can be provided. Furthermore, the light transmittance A2 of the IR absorption layer at 550 nm may be 99% or less, or less than 100%, compared to the light transmittance B2 of the functional member at 550 nm.

[0020] In one embodiment, the IR absorption layer includes any suitable infrared absorbent. The infrared absorbent may be a compound having a maximum absorption peak in the infrared wavelength range (preferably in the wavelength range of 700 to 1200 nm). Preferably, the infrared absorbent does not have a maximum absorption peak in the visible region (preferably in the wavelength range of 400 to 650 nm).

[0021] Examples of infrared absorbers include cyanine compounds, squarylium compounds, thiol nickel complex salt compounds, phthalocyanine compounds, naphthalocyanine compounds, triallylmethane compounds, naphthoquinone compounds, anthraquinone compounds, and aminium salt compounds (e.g., perchlorate of N,N,N',N'-tetrakis(p-di-n-butylaminophenyl)-p-phenylenediaminium, chlorate of phenylenediaminium, hexafluoroantimonate of phenylenediaminium, phenyl Examples include phenylenediaminium borate salts, phenylenediaminium fluoride salts, and phenylenediaminium perchlorate salts; diimonium salt compounds (for example, product names "CIR-FS163M", "CIR-265", "CIR-1080", "CIR-1081", "CIR-1083", and "CIR-1085" manufactured by Nippon Carlit Co., Ltd.); copper compounds obtained by the reaction of copper compounds with bisthiourea compounds, phosphorus compounds with copper compounds, and copper phosphate ester compounds.

[0022] In one embodiment, azo, quinone, triarylmethane, cyanine, phthalocyanine, indigo, and diimonium dyes are used as infrared absorbers. Using these dyes, an IR absorption layer can be formed that exhibits excellent balance between infrared shielding and visible light transmission.

[0023] Inorganic infrared absorbers such as titanium dioxide, zirconium oxide, tantalum oxide, niobium oxide, zinc oxide, tin oxide, indium oxide, indium tin oxide, antimony tin oxide, tungsten oxide, cesium oxide, cesium tungsten oxide, hexaborides, and carbon black may be used as infrared absorbers.

[0024] The above IR absorption layer may further contain a binder. Examples of binders include acrylic resins, urethane-modified acrylic resins, polyurethane resins, polyester resins, melamine resins, polyvinyl acetate, cellulose acetate, polycarbonate, polyacetal, polybutyral, polyamide resins, polystyrene resins, polyimide resins, ABS resins, nitrile rubber, polyvinylidene fluoride, polyvinyl alcohol resins, gelatin, celluloses, thickening polysaccharides, and the like.

[0025] In the above IR absorption layer, the content ratio of the infrared absorbent is preferably 0.01 to 20 parts by weight, more preferably 0.02 to 5 parts by weight, and even more preferably 0.03 to 3 parts by weight, per 100 parts by weight of the binder.

[0026] The above IR absorption layer may contain any other suitable additives. Examples of additives include ultraviolet absorbers, anti-fading agents, fluorescent whitening agents, pH adjusters, defoamers, lubricants, preservatives, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, nucleating agents, inorganic particles, organic particles, viscosity reducers, lubricants, and the like.

[0027] The above-mentioned IR absorption layer can be obtained, for example, by coating any of the above-mentioned functional members with an IR absorption layer forming composition comprising an infrared absorbent, a binder, and additives added as needed. The IR absorption layer forming composition may further contain any suitable solvent. Examples of solvents include alcohols such as methanol, ethanol, n-propanol, and i-propanol; esters such as ethyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate; ethers such as diethyl ether and propylene glycol monomethyl ether; amides such as dimethylformamide; and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. The method for coating the IR absorption layer is not particularly limited and includes, for example, roll coating, flow coating, spray coating, printing, dip coating, bar coating, casting, inkjet printing, and gravure printing.

[0028] In the above IR absorption layer forming composition, the concentration of the infrared absorber is preferably 0.1% to 20% by weight, more preferably 0.5% to 15% by weight, and even more preferably 0.8% to 10% by weight.

[0029] The thickness of the above-mentioned IR absorption layer is preferably 10 nm to 5000 nm, more preferably 30 nm to 4000 nm, even more preferably 50 nm to 2000 nm, and particularly preferably 80 nm to 1000 nm.

[0030] (Polarizing material) The polarizing member 10 is typically an absorbing polarizing member comprising a resin film containing a dichroic substance (sometimes referred to as an absorbing polarizing film), and may further include a protective layer on one or both sides as needed. The protective layer is typically bonded to the absorbing polarizing film via any suitable adhesive layer. Typical adhesives used to form the adhesive layer include UV-curing adhesives.

[0031] The orthogonal transmittance (Tc) of the polarizing member (absorbent polarizing film) is preferably 0.5% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. The single-layer transmittance (Ts) of the polarizing member (absorbent polarizing film) is, for example, 41.0% to 45.0%, and preferably 42.0% or more. The degree of polarization (P) of the polarizing member (absorbent polarizing film) is, for example, 99.0% to 99.997%, and preferably 99.9% or more.

[0032] The above orthogonal transmittance, single-element transmittance, and polarization degree can be measured, for example, using a UV-Vis spectrophotometer. The polarization degree P can be calculated using a UV-Vis spectrophotometer to measure the single-element transmittance Ts, parallel transmittance Tp, and orthogonal transmittance Tc, and then calculated from the obtained Tp and Tc using the following formula. Note that Ts, Tp, and Tc are Y values ​​measured using a 2-degree field of view (C light source) according to JIS Z8701 and corrected for luminous efficiency. Polarization degree P(%)={(Tp-Tc) / (Tp+Tc)} 1 / 2×100

[0033] The thickness of the absorption polarizing film is, for example, 1 μm or more and 20 μm or less, but may also be 2 μm or more and 15 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, or 5 μm or less.

[0034] The above-mentioned absorption polarizing film may be made from a single layer of resin film, or it may be made using a laminate of two or more layers.

[0035] When manufactured from a single layer of resin film, for example, an absorption polarizing film can be obtained by subjecting a hydrophilic polymer film, such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, or a partially saponified ethylene-vinyl acetate copolymer film, to dyeing treatment with a dichroic substance such as iodine or a dichroic dye, and stretching treatment. Among these, an absorption polarizing film obtained by dyeing a PVA film with iodine and uniaxially stretching it is preferred.

[0036] The above iodine staining is carried out, for example, by immersing the PVA-based film in an iodine aqueous solution. The stretching ratio for the above uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the staining treatment, or during the staining process. Alternatively, staining may be performed after stretching. If necessary, the PVA-based film may be subjected to swelling, crosslinking, washing, drying, etc.

[0037] When using the above-mentioned laminate of two or more layers, examples of laminates include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate. An absorption polarizing film obtained using a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate can be produced, for example, by applying a PVA-based resin solution to a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, and obtaining a laminate of a resin substrate and a PVA-based resin layer; or by stretching and dyeing the laminate to make the PVA-based resin layer an absorption polarizing film. In this embodiment, preferably, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, stretching may, if necessary, further include air-stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. In addition, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which it shrinks by 2% or more in the width direction by heating while being transported in the longitudinal direction. Typically, the manufacturing method of this embodiment includes applying an air-assisted stretching treatment, a dyeing treatment, a water-based stretching treatment, and a drying shrinkage treatment to the laminate in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA even when PVA is coated on a thermoplastic resin, making it possible to achieve high optical properties. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as a decrease in the orientation of PVA and dissolution when immersed in water in the subsequent dyeing and stretching processes, making it possible to achieve high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain halides. As a result, the optical properties of the absorption polarizing film obtained through processing steps in which the laminate is immersed in a liquid, such as dyeing and water-based stretching, can be improved. Furthermore, by shrinking the laminate in the width direction through a drying shrinkage treatment, the optical properties can be improved.The resulting resin substrate / absorbent polarizing film laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the absorbent polarizing film), or an appropriate protective layer may be laminated on the peeled surface obtained by removing the resin substrate from the resin substrate / absorbent polarizing film laminate, or on the surface opposite to the peeled surface, depending on the purpose. Details of such a method for manufacturing an absorbent polarizing film are described, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0038] The protective layer is formed from any suitable film that can be used as a protective layer for an absorption polarizing film. Specific examples of materials that make up the main component of the film include cycloolefin (COP) resins such as polynorbornene, polyester resins such as polyethylene terephthalate (PET), cellulose resins such as triacetylcellulose (TAC), polycarbonate (PC), (meth)acrylic, polyvinyl alcohol, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, polyolefin, and acetate transparent resins. Thermosetting resins or UV-curing resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone resins can also be used. In addition, glassy polymers such as siloxane polymers can also be used. Polymer films described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As materials for this film, for example, a resin composition containing a thermoplastic resin having substituted or unsubstituted imide groups in its side chains, and a thermoplastic resin having substituted or unsubstituted phenyl groups and nitrile groups in its side chains can be used. Examples include a resin composition having an alternating copolymer of isobutene and N-methylmaleimide, and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extruded product of the above resin composition. The materials for the resin film can be used individually or in combination.

[0039] The thickness of the protective layer is typically 100 μm or less, for example, 5 μm to 80 μm, preferably 10 μm to 50 μm, and more preferably 15 μm to 35 μm.

[0040] (First phase difference member) The first phase difference member 20 includes a first λ / 4 member 20a. The first λ / 4 member 20a is positioned such that the angle between the absorption axis of the polarizing member 10 (absorption type polarizing film) and the slow phase axis of the first λ / 4 member 20a is preferably 40° to 50°, more preferably 42° to 48°, for example, about 45°.

[0041] As shown in Figures 2(a) and 2(b), the first phase difference member 20 may include, in addition to the first λ / 4 member 20a, a member (a so-called positive C plate) 20b whose refractive index characteristics can exhibit the relationship nz>nx=ny. The first λ / 4 member 20a and the positive C plate 20b can be laminated via an adhesive layer b1. As shown in the illustrated example, it is preferable that the first λ / 4 member 20a is located on the polarizing member 10 side of the positive C plate 20b, but their arrangement may be reversed. The adhesive layer b1 is typically a tack layer or adhesive layer. In this specification, "nx=ny" includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal.

[0042] The in-plane phase difference Re(550) of the first λ / 4 member 20a is, for example, 100 nm to 190 nm, but may also be 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm. Preferably, the first λ / 4 member exhibits an inverse dispersion wavelength characteristic in which the phase difference value increases with the wavelength of the measured light. The Re(450) / Re(550) of the first λ / 4 member is, for example, 0.75 or more and less than 1, but may also be 0.8 or more and 0.95 or less.

[0043] The first λ / 4 member preferably exhibits a refractive index characteristic showing a relationship of nx > ny ≧ nz. Here, "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within a range that does not impair the effects of the present invention, ny < nz may occur. The Nz coefficient of the first λ / 4 member is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

[0044] The first λ / 4 member is formed of any suitable material that can satisfy the above characteristics. The first λ / 4 member can be, for example, a stretched film of a resin film or an alignment cured layer of a liquid crystal compound.

[0045] Examples of the resin contained in the resin film include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, acrylic resins, etc. These resins may be used alone or in combination. Examples of the combination method include blending and copolymerization. When the first λ / 4 member exhibits reverse wavelength dispersion characteristics, a resin film containing a polycarbonate resin or a polyester carbonate resin (hereinafter sometimes simply referred to as a polycarbonate resin) may be preferably used.

[0046] Any suitable polycarbonate resin can be used as the above-mentioned polycarbonate resin. For example, the polycarbonate resin includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic dimethanol, di, tri, or polyethylene glycol, and alkylene glycol or spiroglycol. Preferably, the polycarbonate resin includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, structural units derived from alicyclic dimethanol, and / or structural units derived from di, tri, or polyethylene glycol; more preferably, it includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from di, tri, or polyethylene glycol. The polycarbonate resin may optionally include structural units derived from other dihydroxy compounds. Further details regarding polycarbonate resins suitably used for the first λ / 4 member and methods for forming the first λ / 4 member are described, for example, in Japanese Patent Publication Nos. 2014-10291, 2014-26266, 2015-212816, 2015-212817, and 2015-212818, and the descriptions in these publications are incorporated herein by reference.

[0047] The thickness of the first λ / 4 member, which is composed of a stretched resin film, is, for example, 10 μm to 100 μm, preferably 10 μm to 70 μm, and more preferably 20 μm to 60 μm.

[0048] The orientation-solidified layer of the above-mentioned liquid crystal compound is a layer in which the liquid crystal compound is oriented in a predetermined direction within the layer, and this orientation state is fixed. Note that the term "orientation-solidified layer" is a concept that includes the orientation-cured layer obtained by curing liquid crystal monomers, as described later. In the first λ / 4 member, typically, rod-shaped liquid crystal compounds are oriented in a state where they are aligned along the slow axis direction of the first λ / 4 member (homogenous orientation). Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. Preferably, the liquid crystal compound is polymerizable. If the liquid crystal compound is polymerizable, the orientation state of the liquid crystal compound can be fixed by polymerizing it after orientation.

[0049] The above-mentioned oriented solidified layer of liquid crystal compound (liquid crystal oriented solidified layer) can be formed by applying an orientation treatment to the surface of a predetermined substrate, coating the surface with a coating liquid containing the liquid crystal compound to orient the liquid crystal compound in the direction corresponding to the orientation treatment, and fixing the orientation state. Any appropriate orientation treatment can be used as the orientation treatment. Specifically, these include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of mechanical orientation treatment include rubbing treatment and stretching treatment. Specific examples of physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of chemical orientation treatment include oblique deposition and photo-orientation treatment. Any appropriate conditions can be adopted for each orientation treatment depending on the purpose.

[0050] The orientation of liquid crystal compounds is achieved by treating them at a temperature that exhibits the liquid crystal phase, depending on the type of liquid crystal compound. This temperature treatment causes the liquid crystal compound to enter a liquid crystal state, and it then orients according to the orientation treatment direction on the substrate surface.

[0051] In one embodiment, the orientation state is fixed by cooling the liquid crystal compound oriented as described above. If the liquid crystal compound is polymerizable or crosslinkable, the orientation state is fixed by subjecting the liquid crystal compound oriented as described above to a polymerization treatment or a crosslinking treatment.

[0052] As the above-mentioned liquid crystal compound, any suitable liquid crystal polymer and / or liquid crystal monomer can be used. The liquid crystal polymer and liquid crystal monomer may be used individually or in combination. Specific examples of liquid crystal compounds and methods for producing liquid crystal alignment solidified layers are described, for example, in Japanese Patent Publication No. 2006-163343, Japanese Patent Publication No. 2006-178389, and International Publication No. 2018 / 123551. The descriptions in these publications are incorporated herein by reference.

[0053] The thickness of the first λ / 4 member, which is composed of a liquid crystal alignment solidification layer, is, for example, 1 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 1 μm to 6 μm, and even more preferably 1 μm to 4 μm.

[0054] (Positive C plate) The phase difference Rth(550) in the thickness direction of the positive C plate 20b is preferably -50nm to -300nm, more preferably -70nm to -250nm, even more preferably -90nm to -200nm, and particularly preferably -100nm to -180nm. The in-plane phase difference Re(550) of the positive C plate is, for example, less than 10nm.

[0055] The positive C plate can be formed from any suitable material. Preferably, the positive C plate consists of a film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can be homeotropically oriented may be a liquid crystal monomer or a liquid crystal polymer. A specific example of a method for forming such a liquid crystal compound and positive C plate is the method for forming a liquid crystal compound and phase difference layer described in paragraphs

[0020] to

[0028] of Japanese Patent Application Publication No. 2002-333642. In this case, the thickness of the positive C plate is preferably 0.5 μm to 5 μm.

[0056] (Protective material) The protective member 30 typically includes a base material. The base material can be composed of any suitable film. Examples of materials that make up the main component of the film constituting the base material include cellulose resins such as triacetylcellulose (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyethersulfone resins, polysulfone resins, polystyrene resins, cycloolefin resins such as polynorbornene, polyolefin resins, (meth)acrylic resins, acetate resins, and other resins. The thickness of the base material is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and even more preferably 15 μm to 35 μm.

[0057] The protective member preferably comprises a substrate and a surface treatment layer formed on the substrate. The surface treatment layer may be located on the outermost surface of the optical laminate. The surface treatment layer may have any suitable function. Examples of surface treatment layers include a hard coat layer, an anti-reflective layer, an anti-sticking layer, and an anti-glare layer. The protective member may have two or more surface treatment layers.

[0058] An anti-reflective layer is provided to prevent reflection of external light, etc. Examples of anti-reflective layers include a fluororesin layer, a resin layer containing nanoparticles (typically hollow nanoparticles, such as hollow nanosilica particles), or an anti-reflective layer having a nanostructure (e.g., a moth-eye structure). The thickness of the anti-reflective layer is preferably 0.05 μm to 1 μm. Examples of methods for forming the above resin layer include the sol-gel method, a thermosetting method using isocyanate, and an ionizing radiation curing method (typically a photocuring method) using a crosslinkable monomer (e.g., polyfunctional acrylate) and a photopolymerization initiator.

[0059] The hard coat layer preferably has sufficient surface hardness, excellent mechanical strength, and excellent light transmittance. The hard coat layer can be formed from any suitable resin. Typically, the hard coat layer is formed from an ultraviolet-curable resin. Examples of ultraviolet-curable resins include polyester, acrylic, urethane, amide, silicone, and epoxy resins. The thickness of the hard coat layer is, for example, 0.5 μm or more, preferably 1 μm or more, for example 20 μm or less, preferably 15 μm or less.

[0060] (Adhesive layer) The adhesive layer can be composed of any suitable adhesive. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination, and blending ratio of monomers forming the base resin of the adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc., an adhesive with desired properties for a specific purpose can be prepared. The base resin of the adhesive may be used alone or in combination of two or more types. Acrylic resins are preferably used as the base resin. Specifically, the adhesive layer is preferably composed of an acrylic adhesive.

[0061] For example, an adhesive layer can be formed by coating an adhesive composition containing a base resin, additives such as a crosslinking agent, and a solvent, and then drying it. The adhesive composition may be applied directly to the adherend, or it may be applied to a separate substrate such as a base film (e.g., a release liner). Drying is typically carried out by heating.

[0062] The thickness of the adhesive layer is, for example, 1 μm to 100 μm, preferably 3 μm to 70 μm, more preferably 5 μm to 50 μm, even more preferably 10 μm to 40 μm, and particularly preferably 15 μm to 30 μm.

[0063] B. Display System The above optical laminate can be applied to display systems (e.g., goggles with a display). Figure 3 is a schematic diagram showing an example of a display system including the above optical laminate.

[0064] As shown in Figure 3, the display system 2 comprises a display element 12, a reflective polarizing member 14, a first lens portion 16, a half mirror 18, a first phase difference member 20, a second phase difference member 22, and a second lens portion 24. The reflective polarizing member 14 is positioned in front of the display element 12 on the display surface 12' side and can reflect light emitted from the display element 12. The first lens portion 16 is positioned in the optical path between the display element 12 and the reflective polarizing member 14, and the half mirror 18 is positioned between the display element 12 and the first lens portion 16. The first phase difference member 20 is positioned in the optical path between the display element 12 and the half mirror 18, and the second phase difference member 22 is positioned in the optical path between the half mirror 18 and the reflective polarizing member 14. Although not shown, the display system 2 may further include an absorbing polarizing member between the reflective polarizing member 14 and the second lens portion 24.

[0065] The components positioned in front of the half-mirror (in the illustrated example, the half-mirror 18, the first lens section 16, the second phase difference member 22, the reflective polarizing member 14, and the second lens section 24) are sometimes collectively referred to as the lens section (lens section 4).

[0066] The display element 12 is, for example, a liquid crystal display or an organic EL display, and has a display surface 12' for displaying an image. Light emitted from the display surface 12' passes through, for example, a polarizing member 10 which may be included in the display element 12, and is first linearly polarized.

[0067] In one embodiment, the reflectance of light with a wavelength of 800 nm on the lens portion 4 side of the display element is 10% or more. Even in a display system equipped with such a display element, using the optical laminate can suppress the effects of stray light generated within the display element, and as a result, various sensors can be made to function with high precision. The upper limit of the reflectance of light with a wavelength of 800 nm on the lens portion 4 side of the display element is, for example, 50% (preferably 40%).

[0068] The first phase difference member 20 includes a first λ / 4 member capable of converting a first linearly polarized light incident on the first phase difference member 20 into a first circularly polarized light. If the first phase difference member does not include any members other than the first λ / 4 member, the first phase difference member may correspond to the first λ / 4 member. In addition to the first λ / 4 member, the first phase difference member 20 may also include a member whose refractive index characteristics satisfy the relationship nz>nx=ny (hereinafter also referred to as the "first positive C plate").

[0069] The half mirror 18 transmits light emitted from the display element 12 and reflects the light reflected by the reflective polarizing member 14 back towards the reflective polarizing member 14. The half mirror 18 may be integrally provided with the first lens portion 16.

[0070] The second phase difference member 22 includes a second λ / 4 member that can transmit light reflected by the reflective polarizing member 14 and the half mirror 18 through the reflective polarizing member 14. If the second phase difference member does not include any members other than the second λ / 4 member, the second phase difference member may correspond to the second λ / 4 member. The second phase difference member 22 may be provided integrally with the first lens portion 16.

[0071] The first circularly polarized light emitted from the first λ / 4 member included in the first phase difference member 20 passes through the half mirror 18 and the first lens portion 16 and is converted into a second linearly polarized light by the second λ / 4 member included in the second phase difference member 22. The second linearly polarized light emitted from the second λ / 4 member is reflected towards the half mirror 18 without passing through the reflective polarizing member 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing member 14 is in the same direction as the reflection axis of the reflective polarizing member 14. Therefore, the second linearly polarized light incident on the reflective polarizing member 14 is reflected by the reflective polarizing member 14.

[0072] The second linearly polarized light reflected by the reflective polarizing member 14 is converted into a second circularly polarized light by the second λ / 4 member included in the second phase difference member 22. The second circularly polarized light emitted from the second λ / 4 member passes through the first lens portion 16 and is reflected by the half mirror 18. The second circularly polarized light reflected by the half mirror 18 passes through the first lens portion 16 and is converted into a third linearly polarized light by the second λ / 4 member included in the second phase difference member 22. The third linearly polarized light is transmitted through the reflective polarizing member 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing member 14 is in the same direction as the transmission axis of the reflective polarizing member 14. Therefore, the third linearly polarized light incident on the reflective polarizing member 14 is transmitted through the reflective polarizing member 14.

[0073] The display system 2 may include an absorptive polarizing member (typically an absorptive polarizing film) in front of the reflective polarizing member 14 (closer to the eye). The reflection axis of the reflective polarizing member 14 and the absorption axis of the absorptive polarizing member may be arranged substantially parallel to each other, and the transmission axis of the reflective polarizing member and the transmission axis of the absorptive polarizing member may be arranged substantially parallel to each other. As a result, the third linearly polarized light that has passed through the reflective polarizing member 14 can pass through the absorptive polarizing member as is. The reflective polarizing member and the absorptive polarizing member may be laminated together, for example, with an adhesive layer in between.

[0074] Light that has passed through the reflective polarizing member 14 passes through the second lens portion 24 and enters the user's eye 26.

[0075] For example, the absorption axis of the polarizing member 10 included in the display element 12 and the reflection axis of the reflective polarizing member 14 may be arranged substantially parallel to each other or substantially orthogonal to each other. The angle between the absorption axis of the polarizing member 10 included in the display element 12 and the lagging axis of the first λ / 4 member included in the first phase difference member 20 is, for example, 40° to 50°, may be 42° to 48°, or may be about 45°. The angle between the absorption axis of the polarizing member 10 included in the display element 12 and the lagging axis of the second λ / 4 member included in the second phase difference member 22 is, for example, 40° to 50°, may be 42° to 48°, or may be about 45°.

[0076] In one embodiment, the optical laminate may include a first phase difference member 20. Therefore, the optical laminate may be positioned in the optical path between the display element 12 and the lens portion 4 (substantially between the display element 12 and the half mirror 18). [Examples]

[0077] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The thickness and other values ​​were measured using the measurement method described below. <Thickness> Thicknesses of 10 μm or less were measured using a scanning electron microscope (JEOL Ltd., product name "JSM-7100F"). Thicknesses exceeding 10 μm were measured using a digital micrometer (Anritsu Corporation, product name "KC-351C"). <In-plane phase difference> The in-plane phase difference at 23°C was measured using the "KOBRA-WPR" manufactured by Oji Instruments Co., Ltd.

[0078] [Manufacturing Example 1: Fabrication of Protective Components] An acrylic film having a lactone ring structure was coated with the hard coat layer forming material shown below, and the coated layer was dried to form a hard coat layer with a thickness of 0.5 μm. Next, the anti-reflective layer forming material shown below was applied to the surface of the hard coat layer and heated at 80°C for 1 minute. After heating, the coated layer was exposed to a high-pressure mercury lamp with an integrated light intensity of 300 mJ / cm². 2The coating layer was cured by irradiation with ultraviolet light to form an anti-reflective layer with a thickness of 0.1 μm. This resulted in a protective member 1 (thickness 44 μm) having the configuration of [acrylic film / hard coat layer / anti-reflective layer].

[0079] (Material for forming a hard coat layer) A hard coat layer forming material was prepared by adding 0.5% by weight of a leveling agent to an acrylic resin raw material (manufactured by Dainippon Ink & Co., Ltd., product name: GRANDIC PC1071), and then diluting it with ethyl acetate to a solid content concentration of 50% by weight. The leveling agent is a copolymer produced by copolymerizing dimethylsiloxane, hydroxypropylsiloxane, 6-isocyanate hexyl isocyanuric acid, and aliphatic polyester in a molar ratio of 6.3:1.0:2.2:1.0.

[0080] (Anti-reflection layer forming material) A mixture was prepared by combining 100 parts by weight of a polyfunctional acrylate mainly composed of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., product name "Viscoat #300", solid content 100% by weight), 100 parts by weight of hollow nanosilica particles (manufactured by JGC Catalysts & Chemicals Co., Ltd., product name "Thru-Ria 5320", solid content 20% by weight, weight-average particle size 75 nm), solid nanosilica particles (manufactured by Nissan Chemical Industries, Ltd., product name "MEK-2140Z-AC", solid content 30% by weight, weight-average particle size 10 nm), 12 parts by weight of a fluorine-containing additive (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KY-1203", solid content 20% by weight), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, product name "OMNIRAD907", solid content 100% by weight). To this mixture, a mixed solvent consisting of tert-butyl alcohol, methyl isobutyl ketone, and propylene glycol monomethyl ether acetate in a weight ratio of 60:25:15 was added to adjust the total solid content to 4% by weight, and the mixture was stirred to prepare an anti-reflective layer forming material.

[0081] [Manufacturing Example 2] Manufacturing of Phase Difference Members (λ / 4 Members) 55 parts by weight of the compound represented by formula (I), 25 parts by weight of the compound represented by formula (II), and 20 parts by weight of the compound represented by formula (III) were added to 400 parts by weight of cyclopentanone (CPN), and then heated to 60°C and stirred to dissolve. After that, the solution of the compounds was allowed to return to room temperature, and 3 parts by weight of Irgacure 907 (BASF Japan), 0.2 parts by weight of Megafac F-554 (DIC), and 0.1 parts by weight of p-methoxyphenol (MEHQ) were added to the solution of the compounds, and the mixture was stirred further. The solution after stirring was clear and homogeneous. The obtained solution was filtered through a 0.20 μm membrane filter to obtain a polymerizable composition. A polyimide solution for alignment films was applied to a 0.7 mm thick glass substrate using a spin coating method, dried at 100°C for 10 minutes, and then baked at 200°C for 60 minutes to obtain a coating film. The obtained coating film was then rubbed using a commercially available rubbing device to form an alignment film. Next, the polymerizable composition obtained above was applied to the substrate (essentially the orientation film) by spin coating and dried at 100°C for 2 minutes. After the resulting coated film was cooled to room temperature, it was heated using a high-pressure mercury lamp at 30 mW / cm². 2 A 3 μm thick liquid crystal alignment solidified layer was obtained by irradiating with ultraviolet light at a certain intensity for 30 seconds. The obtained liquid crystal alignment solidified layer had a Re(550) of 130 nm and a Re(450) / Re(550) of 0.851, exhibiting inverse wavelength dispersion characteristics. The refractive index of the obtained liquid crystal alignment solidified layer was 1.57. [ka] [ka]

[0082] [Example 1] (Preparation of composition for forming an IR absorption layer) An infrared absorbent (in powder form, manufactured by Nippon Carlit Co., Ltd., trade name "CIR-LR") was dissolved in methyl isobutyl ketone to prepare an IR absorption layer forming composition with a weight concentration of 0.4%. (Manufacturing of optical laminates) An IR absorption layer-forming composition was applied to the acrylic side of an optical film made of an acrylic film having an anti-reflective layer using a wire bar. After application, the solvent was evaporated by drying in a 120°C oven for 2 minutes to obtain an optical laminate. The coating was performed so that the thickness of the IR absorption layer after drying was 50 nm. (Transmittance measurement) The obtained laminate was transferred to adhesive-backed glass to prepare a sample. Using this sample, the transmittance of the optical laminate in the wavelength range of 780 nm to 2500 nm was measured at room temperature using the transmittance measurement mode of the Hitachi UH-4150 spectrophotometer manufactured by Hitachi High-Tech Science Corporation. Table 1 shows the transmittance at wavelengths of 940 nm, 900 nm, and 550 nm.

[0083] [Example 2] An optical laminate was obtained in the same manner as in Example 1, except that the concentration of the IR dye in the IR absorption layer forming composition was 0.8% by weight and the thickness of the IR absorption layer was 100 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0084] [Example 3] An optical laminate was obtained in the same manner as in Example 1, except that the concentration of the IR dye in the IR absorption layer forming composition was 1.2% by weight and the thickness of the IR absorption layer was 150 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0085] [Example 4] An optical laminate was obtained in the same manner as in Example 1, except that the concentration of the IR dye in the IR absorption layer forming composition was 2% by weight and the thickness of the IR absorption layer was 250 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0086] [Comparative Example 1] The protective member obtained in Manufacturing Example 1 was used as an evaluation sample, and this evaluation sample was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0087] [Table 1]

[0088] [Example 5] (Preparation of composition for forming an IR absorption layer) An IR absorption layer-forming composition was prepared in the same manner as in Example 1. (Manufacturing of optical laminates) An IR absorption layer-forming composition was applied to the liquid crystal alignment surface of a liquid-phase phase difference film (1 / 4λ plate) having a PET substrate using a wire bar. After application, the solvent was evaporated by drying in a 120°C oven for 2 minutes to obtain an optical laminate. The coating was performed so that the thickness of the IR absorption layer after drying was 50 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[0089] [Example 6] An optical laminate was obtained in the same manner as in Example 5, except that the concentration of the IR dye in the IR absorption layer forming composition was 2% by weight and the thickness of the IR absorption layer was 125 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[0090] [Example 7] An optical laminate was obtained in the same manner as in Example 5, except that the concentration of the IR dye in the IR absorption layer forming composition was 4% by weight and the thickness of the IR absorption layer was 250 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[0091] [Comparative Example 2] The phase difference member obtained in Manufacturing Example 2 was used as an evaluation sample, and this evaluation sample was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

[0092] [Table 2]

[0093] As is clear from Tables 1 and 2, according to embodiments of the present invention, it is possible to provide an optical laminate that can cut out unwanted light (infrared light). [Industrial applicability]

[0094] An optical laminate according to an embodiment of the present invention can be used, for example, in the manufacture of goggles with a display, such as VR goggles. [Explanation of symbols]

[0095] 2 Display System 4. Lens section 10 Polarizing component 12 Display elements 14 Reflective polarizing member 16 First lens section 18 Half Mirror 20 First phase difference member 22 Second phase difference member 24 Second lens section 40 IR absorption layer 100 Optical laminate

Claims

1. It comprises an IR absorbing layer and a functional component, The light transmittance of the IR absorption layer at 940 nm is 60% or less. Optical laminate for near-eye devices.

2. The optical laminate for a near-eye device according to claim 1, comprising a polarizing member, a first phase difference member, and a protective member as the functional members.

3. The optical laminate for a near-eye device according to claim 1, wherein the light transmittance A1 of the IR absorbing layer at 900 nm is 90% or less of the light transmittance B1 of the functional member at 900 nm.

4. The optical laminate for a near-eye device according to claim 1, wherein the light transmittance A2 of the IR absorbing layer at 550 nm is 90% or more of the light transmittance B2 of the functional member at 550 nm.

5. The optical laminate for a near-eye device according to claim 1, wherein the ratio (A2 / A1) of the light transmittance A2 of the IR absorption layer at 550 nm to the light transmittance A1 of the IR absorption layer at 900 nm is 1.4 or more.

6. The optical laminate for a near-eye device according to claim 1, wherein the light transmittance A2 of the IR absorption layer at 550 nm is 80% or more.

7. A display system comprising, in this order, a display element, an optical laminate for a near-eye device as described in claim 1, and a lens portion.

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