WO2023176590A1

WO2023176590A1 - Optical laminate with surface protection films and method for manufacturing display system

Info

Publication number: WO2023176590A1
Application number: PCT/JP2023/008561
Authority: WO
Inventors: 光貴野口; 理小島; 咲美 ▲徳▼岡; 周作後藤
Original assignee: 日東電工株式会社
Priority date: 2022-03-14
Filing date: 2023-03-07
Publication date: 2023-09-21
Also published as: TW202345432A

Abstract

The present invention is an optical laminate with surface protection films comprising: an optical laminate which includes at least one optical member and which is used for goggles with a display; and a first surface protection film and a second surface protection film attached to one surface of the optical laminate in the stated order toward the outside. The first surface protection film includes a first base material and a first adhesive layer laminated on the first base material, the second surface protection film includes a second base material and a second adhesive layer laminated on the second base material, the thickness of the second adhesive layer is 8 μm or more, and peel strength P1 of the first surface protection film to the optical laminate and peel strength P2 of the second surface protection film to the first surface protection film satisfy the relationship of P2/P1≤0.8.

Description

Method for manufacturing optical laminate with surface protection film and display system

The present invention relates to an optical laminate with a surface protection film and a method for manufacturing a display system using the optical laminate with a surface protection film.

Image display devices represented by liquid crystal display devices and electroluminescence (EL) display devices (eg, organic EL display devices) are rapidly becoming popular. In image display devices, optical members such as polarizing members and retardation members are generally used to realize image display and improve image display performance (see, for example, Patent Document 1).

In recent years, new uses for image display devices have been developed. For example, goggles with a display (VR goggles) for realizing Virtual Reality (VR) are beginning to be commercialized. In VR goggles, the image displayed on the display panel is enlarged for the viewer to see, so the optical laminate used in VR goggles is more expensive than the optical laminate used in conventional image display devices. Strict defect management is also required.

JP2021-103286A

As mentioned above, optical laminates applied to VR goggles require strict defect control, so the optical laminates applied to VR goggles must be subjected to the final assembly process before they become final products. Up to this point, multiple defect inspections may be performed. On the other hand, the surface of the optical laminate is preferably protected until it is subjected to the final assembly process. Therefore, the main object of the present invention is to provide an optical laminate that can be applied to VR goggles and that can be inspected for defects multiple times with its surface protected.

The present inventors have studied to solve the above problems, and found that the optical laminate protected with a surface protection film is subjected to defect inspection, and the inspection object (i.e., the surface protection film protected We came up with the idea that the above problem could be solved by further protecting the optical laminate (optical laminate) with another surface protection film. Based on this idea, when we produced an optical laminate with a surface protection film in which two surface protection films were laminated and subjected it to defect inspection, air bubbles were generated between the two surface protection films, and these air bubbles caused the optical It has been found that there are cases where it is erroneously detected as a defect in the laminate. Additionally, when peeling off the outer surface protection film to obtain an optical laminate protected only by the inner surface protection film, it was found that the inner surface protection film was sometimes peeled off as well. .

In order to solve the above problem, the present inventors increased the thickness of the adhesive layer of the outer surface protection film and investigated the relationship between the peeling force of the outer surface protection film and the peeling force of the inner surface protection film. It has been discovered that by making adjustments, the above problems can be solved while avoiding these problems, and the present invention has been completed.

According to one aspect of the present invention, there are provided the optical laminates with a surface protection film according to [1] to [8] and the method for manufacturing a display system according to [9].
[1] An optical laminate that includes at least one optical member and is used for goggles with a display, and a first surface protection film that is adhered to one surface of the optical laminate in this order outward. and a second surface protection film, the first surface protection film includes a first base material, and a first adhesive layer laminated on the first base material. layer, the second surface protection film has a second base material, and a second adhesive layer laminated on the second base material, and the second adhesive layer has a thickness of is 8 μm or more, and the peeling force P1 of the first surface protection film to the optical laminate and the peeling force P2 of the second surface protection film to the first surface protection film are P2/P1≦0. An optical laminate with a surface protection film that satisfies the relationship 8.
[2] The optical laminate with a surface protection film according to [1], wherein a peeling force P2 of the second surface protection film with respect to the first surface protection film is 0.5 N/50 mm or less.
[3] The optical laminate with a surface protection film according to [1] or [2], wherein the first surface protection film and the second surface protection film each have a total light transmittance of 85% or more.
[4] The ratio (L2/L1) of the total light transmittance L1 of the first surface protection film to the total light transmittance L2 of the second surface protection film is 0.8 to 1.2, [1 ] to [3]. The optical laminate with a surface protection film according to any one of [3].
[5] The optical laminate has (1) an absorptive polarizing member, a first retardation member, and a protective member in this order toward the first surface protection film, or (2) the second one. A retardation member and a protective member are provided in this order toward the first surface protection film, or (3) a reflective polarizing member and a protection member are provided in this order toward the first surface protection film. , the optical laminate with a surface protection film according to any one of [1] to [4].
[6] The optical laminate with a surface protection film according to [5], wherein the protective member includes a surface treatment layer, and the first surface protection film is attached to the surface treatment layer.
[7] The optical laminate with a surface protection film according to [6], wherein the surface treatment layer includes an antireflection layer, and the first surface protection film is attached to the antireflection layer.
[8] Any one of [1] to [7], wherein the optical laminate has an adhesive layer on the side opposite to the side to which the first surface protection film and the second surface protection film are attached. An optical laminate with a surface protection film according to claim 1.
[9] A method for manufacturing a display system, comprising inspecting the optical laminate with a surface protection film according to any one of [1] to [8] for defects, Obtaining a secondary laminate with a surface protection film by attaching another member to the side opposite to the side to which the surface protection film and the second surface protection film are attached, the secondary laminate with the surface protection film. Peeling the second surface protection film from the body, inspecting the secondary laminate with the surface protection film for defects, and peeling the first surface protection film from the secondary laminate with the surface protection film, obtaining a secondary laminate, the display system being goggles with a display.

According to the optical laminate with a surface protection film according to the embodiment of the present invention, the optical laminate can be attached to the surface of the optical laminate while suppressing the problems of air bubble formation between the surface protection films (resulting in erroneous detection of defects) and poor peeling. Can be inspected for defects multiple times while being protected.

1 is a schematic cross-sectional view of an optical laminate with a surface protection film according to one embodiment of the present invention. 1 is a schematic diagram showing a general configuration of a display system in which an optical laminate according to an embodiment of the present invention can be used. 3 is a schematic cross-sectional view showing an example of an optical laminate that can be used in the display system shown in FIG. 2. FIG. 3 is a schematic cross-sectional view showing an example of an optical laminate that can be used in the display system shown in FIG. 2. FIG. 3 is a schematic cross-sectional view showing an example of an optical laminate that can be used in the display system shown in FIG. 2. FIG. 1 is a schematic diagram illustrating a method of manufacturing a display system according to one embodiment of the present invention. FIG. It is a figure following FIG. 6A. It is a figure following FIG. 6B. It is a figure following FIG. 6C. It is a figure following FIG. 6D.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Further, in order to make the explanation more clear, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the embodiment, but this is just an example, and the interpretation of the present invention is It is not limited.

(Definition of terms and symbols)
Definitions of terms and symbols used herein are as follows.
(1) Refractive index (nx, ny, nz)
"nx" is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., slow axis direction), and "ny" is the direction perpendicular to the slow axis in the plane (i.e., fast axis direction) "nz" is the refractive index in the thickness direction.
(2) In-plane phase difference (Re)
"Re(λ)" is an in-plane retardation measured with light having a wavelength of λnm at 23°C. For example, "Re(550)" is an in-plane retardation measured with light having a wavelength of 550 nm at 23°C. Re(λ) is determined by the formula: Re(λ)=(nx−ny)×d, where d (nm) is the thickness of the layer (film).
(3) Phase difference in thickness direction (Rth)
"Rth (λ)" is a retardation in the thickness direction measured with light having a wavelength of λ nm at 23°C. For example, "Rth (550)" is the retardation in the thickness direction measured with light having a wavelength of 550 nm at 23°C. Rth(λ) is determined by the formula: Rth(λ)=(nx−nz)×d, where d (nm) is the thickness of the layer (film).
(4) Nz coefficient The Nz coefficient is determined by Nz=Rth/Re.
(5) Angle When an angle is referred to in this specification, the angle includes both clockwise and counterclockwise directions with respect to the reference direction. Thus, for example, "45°" means 45° clockwise or counterclockwise. In addition, in this specification, "substantially parallel" includes cases within the range of 0°±10°, for example, 0°±5°, preferably 0°±3°, more preferably 0°±1 90°±5°, preferably 90°±3°, more preferably 90°±1 within the range of °.

A. Optical laminate with surface protection film FIG. 1 is a schematic cross-sectional view of an optical laminate with a surface protection film according to one embodiment of the present invention. The optical laminate 200 with a surface protection film includes at least one optical member, and is attached in this order outward to the optical laminate 100 and one surface of the optical laminate 100, which is used for goggles with a display. It has a first surface protection film 110 and a second surface protection film 120. The first surface protection film 110 has a first base material 112 and a first adhesive layer 114 laminated on the first base material 112. The second surface protection film 120 has a second base material 122 and a second adhesive layer 124 laminated on the second base material 122. The first surface protection film 110 and the second surface protection film 120 are process members that are temporarily attached (temporary attachment) to the optical laminate 100, and when the optical laminate 100 is put into use. It is peeled off and removed. In this specification, the first surface protection film may be referred to as an inner surface protection film, and the second surface protection film may be referred to as an outer surface protection film.

The optical laminate with a surface protection film can be produced by attaching a first surface protection film and a second surface protection film to one surface of the optical laminate. A first surface protection film and a second surface protection film may be attached in this order to one surface of the optical laminate, or a laminate of the first surface protection film and the second surface protection film may be attached to the optical laminate. You may wear it. The adhesive layer side surface of each of the first surface protection film and the second surface protection film may be protected by a release liner until it is used.

A-1. First surface protection film (inner surface protection film)
As shown in FIG. 1, the first surface protection film 110 includes a first base material 112 and a first adhesive layer 114 laminated on the first base material 112.

The total light transmittance L1 of the first surface protection film is, for example, 85% or more, preferably 88% or more, and more preferably 90% or more. If the total light transmittance L1 is within the above range, precise defect inspection can be suitably performed even when the surface of the optical laminate is protected by the first surface protection film.

The haze of the first surface protection film is, for example, 5% or less, preferably 4% or less, more preferably 3% or less, and typically 0.05% or more. As long as the haze is within the above range, precise defect inspection can be suitably performed even when the surface of the optical laminate is protected by the first surface protection film. A surface protection film having a haze within the above range can be obtained, for example, by using a low haze base material and/or an adhesive layer.

The peel force P1 (peel speed: 300 mm/min, peel angle: 180°) of the first surface protection film against the optical laminate is, for example, 1.0 N/50 mm or less, preferably 0.5 N/50 mm or less, more preferably 0. 3N/50mm or less, for example 0.05N/50mm or more, preferably 0.08N/50mm or more, more preferably 0.10N/50mm or more. If the peeling force P1 is within the above range, the problem of poor peeling in which the first surface protective film is peeled off together with the second surface protective film when the second surface protective film is peeled off can be suitably prevented. I can do it.

<First base material>
The first base material is formed of any suitable resin film that can be used as a surface protection film. Specific examples of materials that are the main components of the resin film include cycloolefin (COP) systems such as polynorbornene systems, polyester systems such as polyethylene terephthalate (PET) systems, cellulose systems such as triacetylcellulose (TAC), and polycarbonates. Examples include transparent resins such as (PC), (meth)acrylic, polyvinyl alcohol, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, polyolefin, and acetate. Further, thermosetting resins or ultraviolet curable resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone resins may also be mentioned. Note that "(meth)acrylic resin" refers to acrylic resin and/or methacrylic resin. Other examples include glassy polymers such as siloxane polymers. Furthermore, the polymer film described in JP-A-2001-343529 (WO01/37007) can also be used. Materials for this film include, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in its side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in its side chain. For example, a resin composition containing an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile/styrene copolymer can be used. The polymer film may be, for example, an extrusion molded product of the resin composition. The materials for the resin film can be used alone or in combination.

The first base material preferably contains at least one transparent resin selected from the group consisting of COP-based, PET-based, TAC-based, PC-based, and (meth)acrylic-based, and more preferably COP-based, PET-based, etc. The resin contains at least one transparent resin selected from the group consisting of COP-based, PC-based, and (meth)acrylic-based, and more preferably at least one transparent resin selected from the group consisting of COP-based, PET-based, and PC-based. Contains resin. When the first base material contains the above-mentioned transparent resin, false detections caused by the surface protection film can be more stably reduced in defect inspection.

The first base material may contain an antioxidant, an ultraviolet absorber, a light stabilizer, a nucleating agent, a filler, a pigment, a surfactant, an antistatic agent, and the like. The surface of the first base material (the surface opposite to the first adhesive layer) is provided with an easy-adhesion layer, an easy-slip layer, an anti-blocking layer, an antistatic layer, an anti-reflection layer, an anti-oligomer layer, etc. Good too.

The thickness of the first base material is typically 5 μm or more, preferably 20 μm or more, and typically 200 μm or less, preferably 100 μm or less.

<First adhesive layer>
The first adhesive layer is composed of any suitable adhesive. The adhesive constituting the first adhesive layer typically contains at least one type of adhesive selected from the group consisting of (meth)acrylic adhesives, urethane adhesives, and silicone adhesives. . Preferably, the first adhesive layer contains a (meth)acrylic adhesive.

The (meth)acrylic pressure-sensitive adhesive contains a polymer (hereinafter referred to as (meth)acrylic polymer) of a monomer component whose main component is alkyl (meth)acrylate. In other words, the (meth)acrylic polymer contains a structural unit derived from alkyl (meth)acrylate. The content of structural units derived from alkyl (meth)acrylate is typically 50% by mass or more, preferably 80% by mass or more, more preferably 93% by mass or more, for example 100% by mass or more, preferably 80% by mass or more, and more preferably 93% by mass or more in the (meth)acrylic polymer. It is not more than 98% by mass, preferably not more than 98% by mass.

The alkyl group that the alkyl (meth)acrylate has may be linear or branched. The number of carbon atoms in the alkyl group is, for example, 1 or more and 18 or less. Examples of the alkyl group include methyl group, ethyl group, butyl group, 2-ethylhexyl group, decyl group, isodecyl group, and octadecyl group. Alkyl (meth)acrylates can be used alone or in combination. The average number of carbon atoms in the alkyl group is preferably 3 to 10.

In addition to structural units derived from alkyl (meth)acrylates, the (meth)acrylic polymer may also contain structural units derived from copolymerizable monomers that are polymerizable with alkyl (meth)acrylates. Examples of the copolymerizable monomer include carboxyl group-containing monomers and hydroxyl group-containing monomers. Copolymerizable monomers can be used alone or in combination.

A carboxyl group-containing monomer is a compound that contains a carboxyl group in its structure and also contains a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, maleic acid, fumaric acid, and crotonic acid, with (meth)acrylic acid being preferred. When the (meth)acrylic polymer contains a structural unit derived from a carboxyl group-containing monomer, the adhesive properties of the adhesive layer can be improved. When the (meth)acrylic polymer contains a structural unit derived from a carboxyl group-containing monomer, the content ratio of the structural unit derived from the carboxyl group-containing monomer is preferably 0.01% by mass or more and 10% by mass or less.

A hydroxyl group-containing monomer is a compound that contains a hydroxyl group in its structure and also contains a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethyl cyclohexyl)-methyl acrylate, preferably 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, more preferably 2-hydroxyethyl (meth)acrylate. When the (meth)acrylic polymer contains a structural unit derived from a hydroxyl group-containing monomer, the durability of the adhesive layer can be improved. When the (meth)acrylic polymer contains a structural unit derived from a hydroxyl group-containing monomer, the content of the structural unit derived from the hydroxyl group-containing monomer is preferably 0.01% by mass or more and 10% by mass in the (meth)acrylic polymer. % or less.

The weight average molecular weight Mw of the (meth)acrylic polymer is, for example, 100,000 to 2,000,000, preferably 200,000 to 1,000,000.

Additionally, the (meth)acrylic pressure-sensitive adhesive can contain a crosslinking agent. The crosslinking agent typically includes an organic crosslinking agent and a polyfunctional metal chelate, preferably an organic crosslinking agent. Examples of the organic crosslinking agent include an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, and an imine crosslinking agent, and more preferably an isocyanate crosslinking agent. When the adhesive contains a crosslinking agent, the content of the crosslinking agent is usually 0.01 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the (meth)acrylic polymer.

The above adhesives ((meth)acrylic adhesives, urethane adhesives, and silicone adhesives) may contain various additives in appropriate proportions, if necessary. By adjusting the composition of the base polymer (for example, the type and content ratio of monomers, the type and content ratio of crosslinking agents, etc.), the molecular weight of the base polymer, and the type or content ratio of additives, An adhesive layer having desired adhesiveness can be obtained.

Additives include polymerization initiators, solvents, polymerization catalysts, crosslinking catalysts, silane coupling agents, tackifiers, plasticizers, softeners, deterioration inhibitors, fillers, colorants (pigments, dyes, etc.), light Examples include stabilizers, ultraviolet absorbers, antioxidants, surfactants, antistatic agents, chain transfer agents, and the like.

The thickness of the first adhesive layer is, for example, 10 μm or more, preferably 12 μm or more, and is, for example, 40 μm or less, preferably 30 μm or less, more preferably 25 μm or less. When the first adhesive layer has the above thickness, good protection for the optical laminate can be achieved.

In one embodiment, the ratio (T1/T2) between the thickness T1 of the first adhesive layer and the thickness T2 of the second adhesive layer of the second surface protection film is, for example, 2 or less, preferably 1.8 or less, More preferably 1.5 or less, still more preferably 1.2 or less, even more preferably 1 or less, particularly preferably 0.8 or less, for example 0.1 or more, preferably 0.2 or more, more preferably is 0.3 or more, more preferably 0.4 or more, even more preferably 0.5 or more. If the ratio (T1/T2) is within the above range, generation of bubbles and poor peeling between the first surface protection film and the second surface protection film can be suitably suppressed. Also, good protection for the optical laminate can be provided.

The first adhesive layer may be formed on the surface of the first base material by direct copying or by transfer. In the case of direct copying, the adhesive is directly applied to the surface of the first base material to form the first adhesive layer. In the case of transfer, a first adhesive layer is formed by applying an adhesive to the surface of a release liner, and then a base material is attached to the first adhesive layer. In particular, when the first base material includes an amorphous resin having a relatively low glass transition temperature Tg (for example, 150° C. or lower), the first adhesive layer is preferably formed by a transfer process. With the transfer process, it is possible to prevent the high temperature during drying required for forming the first adhesive layer from affecting the first base material.

A-2. Second surface protection film (outer surface protection film)
As shown in FIG. 1, the second surface protection film 120 includes a second base material 122 and a second adhesive layer 124 laminated on the second base material.

The total light transmittance L2 of the second surface protection film is, for example, 85% or more, preferably 88% or more, and more preferably 90% or more. If the total light transmittance L2 is within the above range, precise defect inspection can be suitably performed even when the surface of the optical laminate is protected by the first surface protection film and the second surface protection film. .

The ratio (L2/L1) between the total light transmittance L1 of the first surface protection film and the total light transmittance L2 of the second surface protection film is, for example, 0.8 to 1.2, preferably 0.85 to 1. 15, more preferably 0.9 to 1.1. If the ratio (L2/L1) is within the above range, precise defect inspection can be suitably performed even when the surface of the optical laminate is protected by the first surface protection film and the second surface protection film. can.

The haze of the second surface protection film is, for example, 5% or less, preferably 4% or less, more preferably 3% or less, and typically 0.05% or more. If the haze is within the above range, precise defect inspection can be suitably performed even when the surface of the optical laminate is protected by the first surface protection film and the second surface protection film.

The peel force P2 (peel speed: 300 mm/min, peel angle: 180°) of the second surface protection film against the first surface protection film is, for example, 0.5 N/50 mm or less, preferably 0.3 N/50 mm or less, more preferably is 0.2N/50mm or less, more preferably 0.1N/50mm or less, for example 0.01N/50mm or more, preferably 0.03N/50mm or more, and even more preferably 0.05N/50mm. It is 50 mm or more. If the peeling force P2 is within the above range, it is possible to suitably prevent the problem of poor peeling in which the first surface protective film is peeled off together with the second surface protective film when the second surface protective film is peeled off. can. Moreover, generation of air bubbles between the first surface protection film and the second surface protection film can be suitably suppressed.

Peeling force P1 (peeling speed: 300 mm/min, peeling angle: 180°) of the first surface protective film against the optical laminate, P2 (peeling speed: 300 mm/min) of the second surface protective film against the first surface protective film The ratio (P2/P1) is typically 0.8 or less, preferably 0.6 or less, more preferably 0.5 or less, for example 0.2 or more. . If the ratio of peeling force (P2/P1) is within the above range, there will be a problem of poor peeling in which the first surface protective film is peeled off together with the second surface protective film when the second surface protective film is peeled off. can be suitably prevented. Moreover, generation of air bubbles between the first surface protection film and the second surface protection film can be suitably suppressed.

<Second base material>
The second base material is formed of any suitable resin film that can be used as a surface protection film. Specific examples of the material that is the main component of the resin film are as described above regarding the first base material.

The second base material may contain antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, fillers, pigments, surfactants, antistatic agents, and the like. The surface of the second base material (the surface opposite to the second adhesive layer) is provided with an easy-adhesion layer, an easy-slip layer, an anti-blocking layer, an antistatic layer, an anti-reflection layer, an anti-oligomer layer, etc. Good too.

The thickness of the second base material is typically 5 μm or more, preferably 20 μm or more, and typically 200 μm or less, preferably 100 μm or less.

<Second adhesive layer>
The second adhesive layer is made of any suitable adhesive. The adhesive constituting the second adhesive layer typically contains at least one adhesive selected from the group consisting of (meth)acrylic adhesives, urethane adhesives, and silicone adhesives. . Preferably, the second adhesive layer contains a (meth)acrylic adhesive. The details of the (meth)acrylic adhesive are as described above regarding the first adhesive layer.

The above-mentioned adhesives ((meth)acrylic adhesives, urethane adhesives, and silicone adhesives) may contain a base polymer (or its constituent monomer components) and, if necessary, additives. Specific examples of the additive are as described above for the first adhesive layer. By adjusting the composition of the base polymer (for example, the type and content ratio of monomers, the type and content ratio of crosslinking agents, etc.), the molecular weight of the base polymer, and the type or content ratio of additives, An adhesive layer having desired adhesiveness can be obtained.

The thickness of the second adhesive layer is typically 8 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and, for example, 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. When the second adhesive layer has the above-mentioned thickness, the generation of air bubbles between the first surface protection film and the second surface protection film is suppressed, and the optical laminate is formed with these surface protection films attached. Defect inspection can be performed satisfactorily.

The method for forming the second adhesive layer includes the same method as the method for forming the first adhesive layer.

A-3. Optical Laminate The optical laminate includes at least one optical member and is used in goggles with a display. Examples of the optical member include an absorptive polarizing member, a reflective polarizing member, a retardation member, and the like. The optical laminate may have an adhesive layer on the surface opposite to the side to which the first surface protection film and the second surface protection film are attached.

A-3-1. Display system to which the optical laminate can be applied FIG. 2 is a schematic diagram showing a general configuration of a display system (goggles with a display) to which the optical laminate can be applied. FIG. 2 schematically shows the arrangement, shape, etc. of each component of the display system 2. As shown in FIG. The display system 2 includes a display element 12, a reflective polarizing member 14, a first lens section 16, a half mirror 18, a first retardation member 20, a second retardation member 22, and a second lens section 24. It is equipped with The reflective polarizing member 14 is disposed at the front of the display element 12 on the display surface 12a side, and can reflect light emitted from the display element 12. The first lens section 16 is arranged on the optical path between the display element 12 and the reflective polarizing member 14, and the half mirror 18 is arranged between the display element 12 and the first lens section 16. The first retardation member 20 is arranged on the optical path between the display element 12 and the half mirror 18, and the second retardation member 22 is arranged on the optical path between the half mirror 18 and the reflective polarizing member 14. There is. Although not shown, the display system 2 may further include an absorptive polarizing member between the reflective polarizing member 14 and the second lens section 24.

The components disposed in front of the half mirror (in the illustrated example, the half mirror 18, the first lens section 16, the second retardation member 22, the reflective polarizing member 14, and the second lens section 24) are collectively assembled into a lens section ( It may also be referred to as a lens section 4).

The display element 12 is, for example, a liquid crystal display or an organic EL display, and has a display surface 12a for displaying images. For example, the light emitted from the display surface 12a passes through a polarizing member 10 that may be included in the display element 12, and is emitted as first linearly polarized light.

The first retardation member 20 includes a first λ/4 member that can convert the first linearly polarized light incident on the first retardation member 20 into first circularly polarized light. When the first retardation member does not include any member other than the first λ/4 member, the first retardation member may correspond to the first λ/4 member. The first retardation member 20 may be provided integrally with the display element 12.

The half mirror 18 transmits the light emitted from the display element 12 and reflects the light reflected by the reflective polarizing member 14 toward the reflective polarizing member 14. The half mirror 18 is provided integrally with the first lens section 16.

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

The first circularly polarized light emitted from the first λ/4 member included in the first retardation member 20 passes through the half mirror 18 and the first lens portion 16, and The second λ/4 member converts the light into a second linearly polarized light. The second linearly polarized light emitted from the second λ/4 member is reflected toward 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 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.

The second linearly polarized light reflected by the reflective polarizing member 14 is converted into second circularly polarized light by the second λ/4 member included in the second retardation member 22, and is emitted from the second λ/4 member. The second circularly polarized light passes through the first lens section 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 section 16 and is converted into third linearly polarized light by the second λ/4 member included in the second retardation 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 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.

As described above, the display system 2 may include an absorbing polarizing member (typically, an absorbing polarizing film) in front of the reflective polarizing member 14 (on the side closer to the eyes). 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. Thereby, the third linearly polarized light that has passed through the reflective polarizing member 14 can pass through the absorbing polarizing member as it is. For example, the reflective polarizing member and the absorbing polarizing member may be laminated with an adhesive layer interposed therebetween.

The light transmitted through the reflective polarizing member 14 passes through the second lens section 24 and enters the user's eyes 26.

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

In the lens portion 4, a space may be formed between the first lens portion 16 and the second lens portion 24. In this case, the member disposed between the first lens section 16 and the second lens section 24 is preferably provided integrally with either the first lens section 16 or the second lens section 24. For example, it is preferable that the member disposed between the first lens part 16 and the second lens part 24 be integrated with either the first lens part 16 or the second lens part 24 via an adhesive layer. According to such a configuration, for example, each member can be easily handled. The adhesive layer may be formed of an adhesive or a pressure-sensitive adhesive. Specifically, the adhesive layer may be an adhesive layer or an adhesive layer. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm.

A-3-2. Configuration of optical laminate FIG. 3 is a schematic cross-sectional view of an optical laminate that can be used in the display system illustrated in FIG. 2. The optical laminate 100a includes an adhesive layer 31, a polarizing member 10, a first retardation member 20, and a first protective member 41 in this order. The polarizing member 10, the first retardation member 20, and the first protection member 41 are laminated with

adhesive layers

51 and 52 interposed therebetween. The adhesive layers 51 and 52 are typically adhesive layers or adhesive layers, preferably adhesive layers. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm. The surface of the adhesive layer 31 is protected by a release liner 61 until it is used. Note that the first surface protection film and the second surface protection film are attached to the surface of the optical laminate 100a on the first protection member 41 side.

In the example shown in FIG. 3, the first retardation member 20 includes, in addition to the first λ/4 member 20a, a member (so-called positive C plate) 20b whose refractive index characteristics can exhibit the relationship nz>nx=ny. Contains. The first retardation member 20 has a laminated structure of a first λ/4 member 20a and a first positive C plate 20b. Unlike the illustrated example, the first positive C plate 20b may be located closer to the polarizing member 10 than the first λ/4 member 20a, or the first positive C plate 20b may be omitted. good. The first λ/4 member 20a and the first positive C plate 20b are laminated, for example, via an adhesive layer (not shown). Further, in the first retardation member 20, the angle between the absorption axis of the polarizing member 10 and the slow axis of the first λ/4 member 20a is preferably 40° to 50°, more preferably 42° to 48°. 45°, for example, about 45°.

The optical laminate 100a can be applied, for example, to manufacturing a display system illustrated in FIG. 2, in which the first retardation member 20 is integrally provided with the display element 12. For example, the release liner 61 is peeled off from the optical laminate 100a, and the polarizing member 10 is attached to the liquid crystal cell together with the back side polarizing member so that the polarizing member 10 becomes the front side (viewing side) polarizing member of the liquid crystal cell. A display system in which the retardation member 20 is integrally provided with a liquid crystal panel (display element) can be manufactured. Further, for example, the first retardation member 20 is integrated with the organic EL panel (display element) by peeling off the release liner 61 from the optical laminate 100a and bonding it to the front of the organic EL panel via the adhesive layer 31. A display system can be manufactured that is provided with a display system. In this case, from the viewpoint of antireflection, a third retardation member including a third λ/4 member may be disposed between the optical laminate 100a and the organic EL panel. The third retardation member may be included in the optical laminate. For example, the optical laminate may include an adhesive layer, a third retardation member, a polarizing member, a first retardation member, and a protection member in this order. The same explanation as for the first λ/4 member can be applied to the third λ/4 member. The third retardation member is configured such that the slow axis of the third λ/4 member makes an angle of, for example, 40° to 50°, 42° to 48°, or about 45° with the absorption axis of the polarizing member 10. may be placed.

<Polarizing member>
The polarizing member 10 is typically an absorption type polarizing member including a resin film containing a dichroic substance (sometimes referred to as an absorption type polarizing film), and if necessary, a protective layer is provided on one or both sides thereof. may further include. The protective layer is typically bonded to the absorption polarizing film via any suitable adhesive layer. A typical example of the adhesive forming the adhesive layer is an ultraviolet curable adhesive.

The cross transmittance (Tc) of the polarizing member (absorbing polarizing film) is preferably 0.5% or less, more preferably 0.1% or less, and still more preferably 0.05% or less. The single transmittance (Ts) of the polarizing member (absorbing polarizing film) is, for example, 41.0% to 45.0%, preferably 42.0% or more. The degree of polarization (P) of the polarizing member (absorbing polarizing film) is, for example, 99.0% to 99.997%, preferably 99.9% or more.

The above-mentioned orthogonal transmittance, single transmittance, and degree of polarization can be measured using, for example, an ultraviolet-visible spectrophotometer. The degree of polarization P can be determined by measuring the single transmittance Ts, parallel transmittance Tp, and cross transmittance Tc using an ultraviolet-visible spectrophotometer, and 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 subjected to visibility correction.
Polarization degree P (%) = {(Tp-Tc)/(Tp+Tc)} ^1/2 ×100

The thickness of the absorption type polarizing film is, for example, 1 μm or more and 20 μm or less, may be 2 μm or more and 15 μm or less, may be 12 μm or less, may be 10 μm or less, or may be 8 μm or less, It may be 5 μm or less.

The above-mentioned absorption type polarizing film may be produced from a single layer resin film, or may be produced using a laminate of two or more layers.

When manufacturing from a single-layer resin film, for example, 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 is coated with iodine or dichloromethane. An absorption type polarizing film can be obtained by performing a dyeing treatment with a dichroic substance such as a color dye, a stretching treatment, and the like. Among these, an absorption type polarizing film obtained by dyeing a PVA film with iodine and uniaxially stretching it is preferred.

The above-mentioned staining with iodine is performed, for example, by immersing the PVA-based film in an iodine aqueous solution. The stretching ratio of the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing process or may be performed while dyeing. Alternatively, it may be dyed after being stretched. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc.

The laminate produced using the above-mentioned laminate of two or more layers is a laminate of a resin base material and a PVA resin layer (PVA resin film) laminated on the resin base material, or a laminate of a resin base material and a PVA resin layer (PVA resin film) laminated on the resin base material, or Examples include a laminate of a material and a PVA-based resin layer formed by coating on the resin base material. An absorption type polarizing film obtained by using a laminate of a resin base material and a PVA resin layer coated on the resin base material can be obtained by, for example, applying a PVA resin solution to the resin base material, drying it, and applying the resin. Forming a PVA-based resin layer on a base material to obtain a laminate of the resin base material and the PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer an absorption type polarizing film. can be produced by; In this embodiment, preferably, a polyvinyl alcohol resin layer containing a halide and a polyvinyl alcohol resin is formed on one side of the resin base material. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, the stretching may further include stretching the laminate in air at a high temperature (for example, 95° C. or higher) before stretching in the boric acid aqueous solution, if necessary. In addition, in the present embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated while being conveyed in the longitudinal direction to shrink by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an in-air auxiliary stretching process, a dyeing process, an underwater stretching process, and a drying shrinkage process in this order. By introducing auxiliary stretching, even when PVA is applied onto a thermoplastic resin, it becomes possible to improve the crystallinity of PVA and achieve high optical properties. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration of orientation and dissolution of PVA when it is immersed in water during the subsequent dyeing and stretching processes, resulting in high optical properties. becomes possible to achieve. Furthermore, when the PVA-based resin layer is immersed in a liquid, disturbance in the orientation of polyvinyl alcohol molecules and deterioration of orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide. Thereby, the optical properties of an absorption polarizing film obtained through a treatment process performed by immersing the laminate in a liquid, such as dyeing treatment and underwater stretching treatment, can be improved. Furthermore, optical properties can be improved by shrinking the laminate in the width direction by drying shrinkage treatment. The obtained resin base material/absorption type polarizing film laminate may be used as is (that is, the resin base material may be used as a protective layer of the absorption type polarizing film), or the resin base material/absorption type polarizing film laminate may be used as is. Any suitable protective layer depending on the purpose may be laminated on the peeled surface from which the resin base material is peeled off, or on the surface opposite to the peeled surface. Details of the manufacturing method of such an absorption type polarizing film are described in, for example, Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire descriptions of these publications are incorporated herein by reference.

The protective layer is formed of any suitable film that can be used as a protective layer of an absorption polarizing film. Specific examples of materials that are the main components of the film include cycloolefin (COP) systems such as polynorbornene systems, polyester systems such as polyethylene terephthalate (PET) systems, cellulose resins such as triacetyl cellulose (TAC), and polycarbonate. Examples include transparent resins such as (PC), (meth)acrylic, polyvinyl alcohol, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, polyolefin, and acetate. Further, thermosetting resins or ultraviolet curable resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone resins may also be mentioned. Note that "(meth)acrylic resin" refers to acrylic resin and/or methacrylic resin. Other examples include glassy polymers such as siloxane polymers. Furthermore, the polymer film described in JP-A-2001-343529 (WO01/37007) can also be used. Materials for this film include, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in its side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in its side chain. For example, a resin composition containing an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile/styrene copolymer can be used. The polymer film may be, for example, an extrusion molded product of the resin composition. The materials for the resin film can be used alone or in combination.

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, more preferably 15 μm to 35 μm.

<First λ/4 member>
The in-plane retardation Re (550) of the first λ/4 member 20a is, for example, 100 nm to 190 nm, may be 110 nm to 180 nm, may be 130 nm to 160 nm, or may be 135 nm to 155 nm. Good too. The first λ/4 member preferably exhibits inverse dispersion wavelength characteristics in which the retardation value increases depending on the wavelength of the measurement light. Re(450)/Re(550) of the first λ/4 member is, for example, 0.75 or more and less than 1, and may be 0.8 or more and 0.95 or less.

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

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

The resins contained in the above resin film include polycarbonate resin, polyester carbonate resin, polyester resin, polyvinyl acetal resin, polyarylate resin, cyclic olefin resin, cellulose resin, polyvinyl alcohol resin, and polyamide resin. , polyimide resin, polyether resin, polystyrene resin, acrylic resin, and the like. 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 dispersion wavelength characteristics, a resin film containing a polycarbonate resin or a polyester carbonate resin (hereinafter sometimes simply referred to as a polycarbonate resin) may be suitably used.

Any suitable polycarbonate resin can be used as the polycarbonate resin. For example, polycarbonate resins contain structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, alicyclic diols, alicyclic dimethanols, di-, tri-, or polyethylene glycols, and alkylene-based dihydroxy compounds. a structural unit derived from at least one dihydroxy compound selected from the group consisting of glycol or spiroglycol. Preferably, the polycarbonate resin contains a structural unit derived from a fluorene dihydroxy compound, a structural unit derived from an isosorbide dihydroxy compound, a structural unit derived from an alicyclic dimethanol, and/or a di, tri, or polyethylene glycol. More preferably, it contains a structural unit derived from a fluorene dihydroxy compound, a structural unit derived from an isosorbide dihydroxy compound, and a structural unit derived from di, tri or polyethylene glycol. . The polycarbonate resin may contain structural units derived from other dihydroxy compounds as necessary. In addition, details of the polycarbonate resin that can be suitably used for the first λ/4 member and the method for forming the first λ/4 member can be found in, for example, JP 2014-10291A and JP 2014-26266A. , JP 2015-212816, A, JP 2015-212817, and JP 2015-212818, and the descriptions of these publications are incorporated herein by reference.

The thickness of the first λ/4 member made 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.

The liquid crystal compound alignment and solidification layer is a layer in which the liquid crystal compound is aligned in a predetermined direction within the layer, and the alignment state is fixed. In addition, the "alignment hardened layer" is a concept that includes an orientation hardened layer obtained by curing a liquid crystal monomer as described below. In the first λ/4 member, rod-shaped liquid crystal compounds are typically aligned in the slow axis direction of the first λ/4 member (homogeneous alignment). Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. The liquid crystal compound is preferably polymerizable. If the liquid crystal compound is polymerizable, the alignment state of the liquid crystal compound can be fixed by aligning the liquid crystal compound and then polymerizing it.

The liquid crystal compound alignment and solidification layer (liquid crystal alignment solidification layer) is produced by subjecting the surface of a predetermined base material to an alignment treatment, applying a coating liquid containing the liquid crystal compound to the surface, and subjecting the liquid crystal compound to the alignment treatment. It can be formed by orienting it in a corresponding direction and fixing the orientation state. Any suitable orientation treatment may be employed as the orientation treatment. Specifically, mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment can be mentioned. Specific examples of mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of physical alignment treatment include magnetic field alignment treatment and electric field alignment treatment. Specific examples of chemical alignment treatment include oblique vapor deposition and photo alignment treatment. As the treatment conditions for various orientation treatments, any appropriate conditions may be adopted depending on the purpose.

The alignment of the liquid crystal compound is carried out by treatment at a temperature that exhibits a liquid crystal phase depending on the type of liquid crystal compound. By performing such temperature treatment, the liquid crystal compound assumes a liquid crystal state, and the liquid crystal compound is oriented in accordance with the orientation treatment direction of the substrate surface.

In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned as described above. When the liquid crystal compound is polymerizable or crosslinkable, the alignment state is fixed by subjecting the liquid crystal compound aligned as described above to polymerization treatment or crosslinking treatment.

Any suitable liquid crystal polymer and/or liquid crystal monomer can be used as the liquid crystal compound. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination. Specific examples of liquid crystal compounds and methods for producing liquid crystal alignment solidified layers are described in, for example, JP 2006-163343A, JP 2006-178389A, and WO 2018/123551A. The descriptions of these publications are incorporated herein by reference.

The thickness of the first λ/4 member composed of the liquid crystal alignment solidified layer is, for example, 1 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 1 μm to 6 μm, and still more preferably 1 μm to 4 μm. be.

<First positive C plate>
The retardation Rth (550) in the thickness direction of the first positive C plate 20b is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, and still more preferably -90 nm to -200 nm. , particularly preferably -100 nm to -180 nm. Here, "nx=ny" includes not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. The in-plane retardation Re (550) of the first positive C plate is, for example, less than 10 nm.

The first positive C-plate may be formed of any suitable material. The first positive C-plate preferably consists of a film containing liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the method for forming such a liquid crystal compound and positive C plate include the method for forming the liquid crystal compound and the retardation layer described in [0020] to [0028] of JP-A No. 2002-333642. In this case, the thickness of the first positive C plate is preferably 0.5 μm to 5 μm.

<First protection member>
The first protection member 41 typically includes a base material. The substrate may be comprised of any suitable film. Materials that are the main components of the film constituting the base material include, for example, cellulose resins such as triacetyl cellulose (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, Examples include polysulfone-based, polystyrene-based, cycloolefin-based resins such as polynorbornene, polyolefin-based resins, (meth)acrylic-based resins, and acetate-based 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.

The first protective member preferably has a base material and a surface treatment layer formed on the base material. The first protection member having the surface treatment layer may be arranged such that the surface treatment layer is located on the front side. Specifically, the surface treatment layer may be located on the outermost surface of the optical laminate 100a. The surface treatment layer may have any suitable function. Examples of the surface treatment layer include a hard coat layer, an antireflection layer, an antisticking layer, and an antiglare layer. The first protection member may have two or more surface treatment layers.

The antireflection layer is provided to prevent reflection of external light and the like. Examples of the antireflection layer include a fluororesin layer, a resin layer containing nanoparticles (typically hollow nanoparticles, such as hollow nanosilica particles), or an antireflection layer having a nanostructure (e.g. moth-eye structure). . The thickness of the antireflection layer is preferably 0.05 μm to 1 μm. Examples of methods for forming the resin layer include a sol-gel method, a thermosetting method using isocyanate, and an ionizing radiation curing method using a crosslinking monomer (e.g., polyfunctional acrylate) and a photopolymerization initiator (typically a photopolymerization method). curing method). In one embodiment, the antireflection layer is provided on the outermost surface of the first protective member, and an inner surface protection film is attached to the surface of the antireflection layer. According to the embodiment in which the antireflection layer is provided on the outermost surface of the first protective member, an excellent antireflection effect can be achieved in a display system in which a space is formed between the half mirror 18 and the first retardation member 20. Obtainable.

The hard coat layer preferably has sufficient surface hardness, excellent mechanical strength, and excellent light transparency. The hard coat layer may be formed from any suitable resin. The hard coat layer is typically formed from an ultraviolet curable resin. Examples of the ultraviolet curable resin 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, and, for example, 20 μm or less, preferably 15 μm or less.

<Adhesive layer>
Adhesive layer 31 may 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 that form the base resin of the adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc., adhesives can have desired characteristics depending on the purpose. can be prepared. The base resin of the adhesive may be used alone or in combination of two or more types. As the base resin, acrylic resin is preferably used. Specifically, the adhesive layer is preferably composed of an acrylic adhesive.

The thickness of the adhesive layer is typically 1 μm or more, preferably 5 μm or more, more preferably 12 μm or more, and typically 60 μm or less, preferably 30 μm or less, more preferably 23 μm or less.

<Release liner>
Release liner 61 is formed of any suitable resin film. Specific examples of the material that is the main component of the resin film include polyethylene terephthalate (PET), polyethylene, and polypropylene. The materials for the resin film can be used alone or in combination. The release liner may be transparent (eg, haze of 5% or less, and such as 3% or less) or non-transparent. When inspecting the optical laminate with a surface protection film attached with a release liner, the release liner is preferably transparent.

A release treatment layer may be provided on the surface of the release liner 61 that comes into contact with the adhesive layer 31. Examples of the mold release treatment agent forming the mold release treatment layer include silicone mold release treatment agents, fluorine mold release treatment agents, and long chain alkyl acrylate type mold release treatment agents. The mold release treatment agents can be used alone or in combination. The thickness of the release treatment layer is typically 50 nm or more and 400 nm or less.

The thickness of the release liner is typically 5 μm or more, preferably 20 μm or more, and typically 60 μm or less, preferably 45 μm or less. In addition, when a mold release treatment layer is applied, the thickness of the release liner is the thickness including the thickness of the mold release treatment layer.

FIG. 4 is a schematic cross-sectional view of another optical laminate that may be used in the display system illustrated in FIG. 2. The optical laminate 100b includes an adhesive layer 32, a second retardation member 22, and a second protection member 42 in this order. The second retardation member 22 and the second protection member 42 are laminated with an adhesive layer 53 in between. The adhesive layer 53 is typically an adhesive layer or an adhesive layer, and preferably an adhesive layer. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm. The surface of the adhesive layer 32 is protected by a release liner 62 until it is ready for use. The inner surface protection film and the outer surface protection film are attached to the surface of the optical laminate 100b on the second protection member 42 side.

In the example shown in FIG. 4, the second retardation member 22 includes, in addition to the second λ/4 member 22a, a member (so-called positive C plate) 22b whose refractive index characteristics can exhibit the relationship nz>nx=ny. Contains. The second retardation member 22 has a laminated structure of a second λ/4 member 22a and a second positive C plate 22b. Unlike the illustrated example, the second positive C plate 22b may be located closer to the second protection member 42 than the second λ/4 member 22a, and the second positive C plate 22b may be omitted. It's okay. The second λ/4 member 22a and the second positive C plate 22b are laminated, for example, via an adhesive layer (not shown).

The optical laminate 100b can be applied, for example, to manufacturing a display system illustrated in FIG. 2 in which the second retardation member 22 is integrally provided with the first lens portion 16. Specifically, by peeling off the release liner 62 from the optical laminate 100b and bonding it to the first lens part 16 via the adhesive layer 32, the second retardation member 22 is integrally attached to the first lens part 16. A display system provided can be manufactured.

<Second λ/4 member>
The in-plane retardation Re (550) of the second λ/4 member 22a is, for example, 100 nm to 190 nm, may be 110 nm to 180 nm, may be 130 nm to 160 nm, or may be 135 nm to 155 nm. Good too. The second λ/4 member preferably exhibits inverse dispersion wavelength characteristics in which the retardation value increases depending on the wavelength of the measurement light. Re(450)/Re(550) of the second λ/4 member is, for example, 0.75 or more and less than 1, and may be 0.8 or more and 0.95 or less.

The second λ/4 member preferably exhibits a refractive index characteristic of nx>ny≧nz. Here, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where ny and nz are substantially equal. Therefore, there may be a case where ny<nz within a range that does not impair the effects of the present invention. The Nz coefficient of the second λ/4 member is preferably 0.9 to 3, more preferably 0.9 to 2.5, even more preferably 0.9 to 1.5, and particularly preferably is 0.9 to 1.3.

The second λ/4 member is formed of any suitable material that can satisfy the above characteristics. The second λ/4 member may be, for example, a stretched film of a resin film or an oriented solidified layer of a liquid crystal compound. The same explanation as for the first λ/4 member can be applied to the second λ/4 member composed of a stretched resin film or an oriented solidified layer of a liquid crystal compound. The first λ/4 member and the second λ/4 member may have the same configuration (for example, forming material, thickness, optical properties, etc.) or may have different configurations.

<Second positive C plate>
The retardation Rth (550) in the thickness direction of the second positive C plate 22b is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, and still more preferably -90 nm to -200 nm. , particularly preferably -100 nm to -180 nm. Here, "nx=ny" includes not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. The in-plane retardation Re (550) of the second positive C plate is, for example, less than 10 nm.

The second positive C plate is formed of any suitable material that can satisfy the above characteristics. The same explanation as for the first positive C plate can be applied to the constituent material of the second positive C plate. The first positive C plate and the second positive C plate may have the same configuration (for example, forming material, thickness, optical properties, etc.) or may have different configurations.

<Second protection member>
The second protection member 42 typically includes a base material, and preferably includes a base material and a surface treatment layer formed on the base material. In this case, the surface treatment layer may be located on the outermost surface of the optical laminate 100b. Regarding the details of the base material and the surface treatment layer, the same explanation as for the first protective member can be applied. According to an embodiment in which an antireflection layer is provided as a surface treatment layer on the outermost surface of the second protection member 42, the second retardation member 22 is integrated with the first lens portion 16, and the reflective polarizing member 14 is integrated with the second protection member 42. In a display system that is integrated with the lens portion 24 and a space is formed between them, an excellent antireflection effect can be obtained.

The same explanation as for the adhesive layer 31 and release liner 61 used in the optical laminate 100a can be applied to the adhesive layer 32 and release liner 62 used in the optical laminate 100b, respectively.

FIG. 5 is a schematic cross-sectional view of yet another optical laminate that can be used in the display system illustrated in FIG. 2. The optical laminate 100c includes an adhesive layer 33, an absorptive polarizing member 11, a reflective polarizing member 14, and a third protection member 43 in this order. The absorption axis of the absorption type polarization member 11 and the reflection axis of the reflection type polarization member 14 are arranged to be substantially parallel to each other, and the transmission axis of the absorption type polarization member 11 and the transmission axis of the reflection type polarization member 14 are arranged to be substantially parallel to each other. are arranged substantially parallel to each other. The absorptive polarizing member 11, the reflective polarizing member 14, and the third protection member 43 are laminated with

adhesive layers

54 and 55 interposed therebetween. The adhesive layers 54 and 55 are typically adhesive layers or adhesive layers, preferably adhesive layers. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm. The surface of the adhesive layer 33 is protected by a release liner 63 until it is used. The inner surface protection film and the outer surface protection film are attached to the third protection member 43 side surface of the optical laminate 100c.

The optical laminate 100c can be applied, for example, to manufacturing a display system of an embodiment that further includes an absorptive polarizing member between the reflective polarizing member 14 and the second lens part 24 in the display system illustrated in FIG. . Specifically, by peeling off the release liner 63 from the optical laminate 100c and bonding it to the second lens part 24 via the adhesive layer 33, the reflective polarizing member 14 and the absorbing polarizing member 11 are separated from each other by the second lens part 24. A display system integrated with the lens portion 24 can be manufactured.

<Reflective polarizing member>
The reflective polarizing member 14 can transmit polarized light parallel to its transmission axis (typically, linearly polarized light) while maintaining its polarized state, and can reflect light with other polarized states. The cross transmittance (Tc) of the reflective polarizing member may be, for example, 0.01% to 3%. The single transmittance (Ts) of the reflective polarizing member may be, for example, 43% to 49%, preferably 45 to 47%. The degree of polarization (P) of the reflective polarizing member may be, for example, 92% to 99.99%. The reflective polarizing member is typically composed of a film having a multilayer structure (sometimes referred to as a reflective polarizing film). Commercially available reflective polarizing films include, for example, 3M's product names "DBEF" and "APF" and Nitto Denko's product name "APCF".

<Third protection member>
The third protection member 43 typically includes a base material, and preferably includes a base material and a surface treatment layer formed on the base material. In this case, the surface treatment layer may be located on the outermost surface of the optical laminate 100c. Regarding the details of the base material and the surface treatment layer, the same explanation as for the first protective member can be applied. According to the embodiment in which an antireflection layer is provided as a surface treatment layer on the outermost surface of the third protection member 43, the second retardation member 22 is integrated with the first lens portion 16, and the reflective polarizing member 14 is integrated with the second protection member 43. In a display system that is integrated with the lens portion 24 and a space is formed between them, an excellent antireflection effect can be obtained.

The absorption type polarizing member 11, adhesive layer 33, and release liner 63 used in the optical laminate 100c are explained in the same manner as the polarizing member 10, adhesive layer 31, and release liner 61 used in the optical laminate 100a, respectively. can be applied.

B. Method for manufacturing a display system According to another aspect of the present invention, there is provided a method for manufacturing a display system (goggles with a display) using the optical laminate with a surface protection film described in Section A. A method of manufacturing a display system according to one embodiment of the present invention includes:
Inspecting the optical laminate with a surface protection film according to item A for defects;
Adhering another member to the side opposite to the side to which the inner surface protection film and the outer surface protection film are attached of the optical laminate with the surface protection film to obtain a secondary laminate with the surface protection film;
Peeling the outer surface protection film from the secondary laminate with the surface protection film,
inspecting the secondary laminate with the surface protection film for defects; and peeling the inner surface protection film from the secondary laminate with the surface protection film to obtain a secondary laminate;
In this order.
The obtained secondary laminate is subjected to an assembly process and assembled with other members to form a display system. Hereinafter, an example of a method for manufacturing a display system using an optical laminate with a surface protection film having the optical laminate 100a illustrated in FIG. 3 will be described with reference to FIGS. 6A to 6E.

As shown in FIG. 6A, the optical laminate 200 with a surface protection film to be inspected has an optical laminate 100a, and an inner surface protection film 110 and an outer surface on the surface of the optical laminate 100a on the first protection member 41 side. The protective film 120 is pasted outward in this order. Defect inspection performed on the optical laminate with a surface protection film includes visual defect inspection and automatic optical inspection (AOI) using a known automatic defect inspection device. The defect inspection may be of a transmission type or a reflection type. In one embodiment, the defect inspection is reflective. In this case, for example, an inspection light is irradiated from a light source onto the surface of the outer surface protection film 120 side of the optical laminate with a surface protection film 200, and the reflected light image is acquired by an imaging device C such as a line sensor or a two-dimensional camera. Then, defect detection is performed based on the acquired image data. In another embodiment, the defect inspection is transparent. In this case, for example, an inspection light is irradiated from a light source to the release liner 61 side surface of the optical laminate 200 with a surface protection film, a transmitted light image is acquired by the imaging device C, and based on the acquired image data, , performs defect detection. If necessary, the reflection type inspection and the transmission type inspection may be combined. Preferably, the inspection is performed in a clean room. Detected defects include scratches, foreign objects, bubbles, dirt, and the like. The size of the defect can be, for example, between 45 μm and 500 μm. Note that another surface protection film may be provided on the outside of the outer surface protection film and/or release liner of the optical laminate with a surface protection film to be inspected until it is subjected to inspection. By peeling off another surface protection film immediately before inspection, it is possible to prevent scratches, foreign matter, dirt, etc. from adhering to the outer surface protection film and/or release liner surface, and as a result, these can be removed from the optical laminate. It is possible to prevent erroneous detection, which is a drawback. As such another surface protection film, one is preferably used that has a lower adhesion force to the outer surface protection film or release liner than the adhesion force of the outer surface protection film or release liner to the adherend.

Next, another member is attached to the side opposite to the side to which the inner surface protection film and the outer surface protection film of the optical laminate with the surface protection film that was determined to be good in the defect inspection described above is applied to protect the surface. A secondary laminate with film is obtained. Specifically, as shown in FIG. 6B, the release liner 61 is peeled off from the optical laminate 200 with the surface protection film attached, and the release liner 61 is attached to another member 300 using the exposed adhesive layer 31. A secondary laminate 400a is obtained. In one embodiment, the other member 300 is an optical member such as an organic EL panel or a liquid crystal cell, and the optical laminate with a surface protection film is bonded to the viewing side (front) surface thereof.

When attached to another member 300, the optical laminate 200 with a surface protection film may have a shape corresponding to the shape of the other member 300. For example, the optical laminate 200 with a surface protection film is formed into a long shape, and after the defect inspection described above, it can be processed into a desired shape by cutting, punching, machining, or the like. Alternatively, the optical laminate 200 with a surface protection film may be subjected to defect inspection after being processed into a desired shape.

Next, as shown in FIGS. 6C and 6D, the outer surface protection film 120 is peeled off from the surface protection film-attached secondary laminate 400a, and the obtained surface protection film-attached secondary laminate 400b is inspected for defects. An example of the defect inspection performed on the secondary laminate with a surface protection film is the same inspection as the defect inspection performed on the optical laminate 200 with a surface protection film.

Next, as shown in FIG. 6E, the inner surface protection film 110 is peeled off from the surface protection film-attached secondary laminate 400b, which was determined to be good in the defect inspection, to obtain a secondary laminate 400c.

The secondary laminate 400c is subjected to an assembly process and assembled with other members (for example, the optical laminate shown in FIG. 4 or 5) to configure a display system.

According to the above manufacturing method, it is possible to perform multiple defect inspections on the optical laminate while the surface is protected, and there is no need for scratches, dirt, etc. to adhere to the surface until just before it is incorporated into a display system. can be suitably prevented. This effect occurs when processes such as manufacturing the optical laminate, manufacturing intermediate products (e.g. display elements) using the optical laminate, and manufacturing (assembly) the display system using the intermediate products are performed at different locations. This is particularly advantageous when In one embodiment, an optical laminate manufactured by an optical laminate manufacturer is inspected for defects in the form of an optical laminate with a surface protection film to which inner and outer surface protection films have been applied (e.g., FIG. 6A ); Items judged to be good in the defect inspection are shipped as the first semi-finished product to a display element manufacturer; The display element manufacturer then converts the optical laminate with a surface protection film into liquid crystal cells, organic EL panels, etc. A display element (liquid crystal display element, organic EL display element, etc.) is produced (for example, Fig. 6B); from here, the outer surface protection film is peeled off and the inner surface protection film is protected. A defect inspection is performed on the display element in the state shown in FIG. The display element, which is ready for use after the inner surface protective film is peeled off by the display system manufacturer, can be assembled with other components (eg, FIG. 6E). According to the manufacturing method of this embodiment, defects (scratches, foreign objects, dirt, etc.), defect inspection when manufacturing a display element that is a second semi-finished product, and prevention of defects (scratches, foreign objects, dirt, etc.) when shipping the second semi-finished product. As a result, it can contribute to efficient manufacturing of final products.

The method of manufacturing the display system is not limited to the illustrated example. For example, the outer surface protective film may be peeled off before the release liner is peeled off and attached to another component, and a second defect inspection may be performed before attachment to another component. It's okay. For example, the inner surface protection film may be peeled off after the optical laminate is placed at a predetermined position of the display system.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. Note that the thickness is a value measured by the following measuring method.
<Thickness>
The thickness was measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C").
<In-plane phase difference or thickness direction phase difference>
A sample was prepared by cutting out the central part in the width direction of the member to be measured into a square shape with a width of 50 mm and a length of 50 mm, with one side parallel to the width direction of the member. The in-plane retardation and thickness direction retardation of the sample were measured using "KOBRA-WPR" manufactured by Oji Scientific Instruments.

[Production Example 1A: Production of surface protection film A]
<Acrylic polymer A>
In a reaction vessel equipped with a thermometer, a stirrer, a cooler, and a nitrogen gas introduction tube, 100 parts by mass of 2-ethylhexyl acrylate (2EHA) and 4 parts by mass of hexyl acrylate were added as monomer components, and 2,2'- as a polymerization initiator. 0.2 parts by mass of azobisisobutyronitrile (AIBN) was charged together with 150 parts by mass of ethyl acetate, and while stirring gently at 23°C, nitrogen gas was introduced to perform nitrogen substitution. Thereafter, a polymerization reaction was carried out for 6 hours while maintaining the liquid temperature at around 65° C. to prepare a solution of acrylic polymer A (concentration: 40% by mass). The weight average molecular weight of acrylic polymer A was 530,000.

<Adhesive composition A>
Ethyl acetate was added to the solution of acrylic polymer A to dilute it to a concentration of 20% by mass. To 500 parts by mass of this solution (solid content: 100 parts by mass), 5 parts by mass of an isocyanurate of hexamethylene diisocyanate ("Coronate HX" manufactured by Tosoh Corporation) as a crosslinking agent, and a surfactant ("Aqualon" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) HS-10'') was added and stirred to prepare adhesive composition A.

<Surface protection film A>
Adhesive composition A was applied to the surface (corona treated surface) of a base material (PET film, "CE901-38" manufactured by KOLON, thickness 38 μm), and then dried to form an adhesive layer (thickness 10 μm). . Next, a release liner (manufactured by Toyobo Co., Ltd., product number TG704) was attached to the surface of the adhesive layer opposite to the base material.

[Production Example 1B: Production of surface protection film B]
<Adhesive composition B>
Ethyl acetate was added to the solution of acrylic polymer A obtained in Production Example 1A to dilute the solution to a concentration of 20% by mass. To 500 parts by mass of this solution (solid content 100 parts by mass), 4 parts by mass of an isocyanurate of hexamethylene diisocyanate ("Coronate HX" manufactured by Tosoh Corporation) as a crosslinking agent, and a surfactant ("Aqualon" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) HS-10'') was added and stirred to prepare adhesive composition B.

<Surface protection film B>
Adhesive composition B was applied to the surface (corona-treated surface) of a base material (PET film, manufactured by Mitsubishi Chemical Corporation, product number T100C38, thickness 38 μm), and then dried to form an adhesive layer (thickness 20 μm). Next, a release liner (manufactured by Toyobo Co., Ltd., product number TG704) was attached to the surface of the adhesive layer opposite to the base material.

[Production Example 1C: Production of surface protection film C]
<Acrylic polymer C>
In a reaction vessel equipped with a thermometer, a stirrer, a cooler, and a nitrogen gas introduction tube, 96.2 parts by mass of 2-ethylhexyl acrylate (2EHA) and 3.8 parts by mass of hydroxyethyl acrylate (HEA) were placed as monomer components, and the polymerization As an initiator, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was charged together with 150 parts by mass of ethyl acetate, and nitrogen gas was introduced while stirring gently at 23°C to perform nitrogen substitution. . Thereafter, a polymerization reaction was carried out for 6 hours while maintaining the liquid temperature at around 65° C. to prepare a solution of acrylic polymer C (concentration: 40% by mass). The weight average molecular weight of acrylic polymer C was 540,000.

<Adhesive composition C>
Ethyl acetate was added to the solution of acrylic polymer C to dilute it to a concentration of 20% by mass. To 500 parts by mass of this solution (solid content: 100 parts by mass), 4 parts by mass of an isocyanurate of hexamethylene diisocyanate ("Coronate HX" manufactured by Tosoh Corporation) as a crosslinking agent, and dibutyltin dilaurate (1% by mass ethyl acetate) as a crosslinking catalyst. Solution) 3 parts by mass (solid content: 0.03 parts by mass) were added and stirred to prepare adhesive composition C.

<Surface protection film C>
A PET film (product number T100C38, manufactured by Mitsubishi Chemical Corporation, thickness 38 μm) was used as a base material, and adhesive composition C was applied to the corona-treated surface of the film, followed by drying to form an adhesive layer (thickness 5 μm). Next, a release liner (manufactured by Toyobo Co., Ltd., product number TG704) was attached to the surface of the adhesive layer opposite to the base material. As a result, a surface protection film C was obtained.

[Production Example 1D: Production of surface protection film D]
Same as Production Example 1C except that a PET film ("CE905-38" manufactured by KOLON, thickness 38 μm) was used as the base material, and adhesive composition C was applied to one side of the film to form an adhesive layer with a thickness of 15 μm. A surface protection film D was obtained.

The following evaluations (1) and (2) were performed on the above surface protection films A to D. The results are shown in Table 1 along with the thicknesses of the base material and adhesive layer.
(1) Total light transmittance and haze For each surface protection film, the release liner was peeled off from the adhesive layer, and light was irradiated from the substrate side using a haze meter (“HZ-V3” manufactured by Suga Test Instruments Co., Ltd.). According to JIS-K-7136, haze was calculated using haze (%) = (Td/Tt) x 100 (Td: diffuse transmittance, Tt: total light transmittance). Total light transmittance was measured in accordance with JIS-K-7316.
(2) Peeling force Cut the surface protection film into a size of 50 mm in width and 100 mm in length, peel off the release liner from the adhesive layer, and roll it onto the adherend at a pressure of 0.25 MPa and a feed speed of 0.3 m/min. It was crimped. This sample was allowed to stand for 30 minutes in an environment with a temperature of 23°C and a relative humidity of 50%, and then a peel test was conducted under the same environment at a peel angle of 180° and a tensile speed of 300 mm/min, and the 180° peel force was measured. . Regarding surface protection films A to C, surface protection film D was used as an adherend, and the peeling force of surface protection film D against the substrate side surface was measured. Regarding the surface protection film D, the optical laminate A prepared in Example 1 described below was used as an adherend, and the peeling force against the surface of the protection member A was measured. The measurement was performed with N=10, and the average value was taken as the peeling force.

[Production Example 2: Production of polarizing film A]
A long roll of polyvinyl alcohol (PVA) resin film (manufactured by Kuraray Co., Ltd., product name "PE3000") with a thickness of 30 μm was uniaxially stretched in the longitudinal direction so as to be 5.9 times the length in the longitudinal direction using a roll stretching machine. At the same time, swelling, dyeing, crosslinking, and washing treatments were performed, and finally a drying treatment was performed to prepare an absorption type polarizing film with a thickness of 12 μm.
Specifically, in the swelling treatment, the film was stretched 2.2 times while being treated with pure water at 20°C. Next, the dyeing process was carried out in an aqueous solution at 30°C in which the weight ratio of iodine and potassium iodide was 1:7, and the iodine concentration was adjusted so that the single transmittance of the obtained absorption type polarizing film was 45.0%. It was stretched 1.4 times during processing. Furthermore, a two-stage crosslinking process was adopted for the crosslinking process, and the first crosslinking process was performed in an aqueous solution containing boric acid and potassium iodide at 40°C, and was stretched to 1.2 times. The boric acid content of the aqueous solution for the first stage crosslinking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. In the second stage of crosslinking treatment, the film was stretched to 1.6 times while being treated in an aqueous solution containing boric acid and potassium iodide at 65°C. The boric acid content of the aqueous solution for the second stage crosslinking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. Further, the cleaning treatment was performed using a potassium iodide aqueous solution at 20°C. The potassium iodide content of the aqueous solution for cleaning treatment was 2.6% by weight. Finally, the drying process was carried out at 70° C. for 5 minutes to obtain an absorption type polarizing film.
A triacetyl cellulose (TAC) resin film with HC (TAC thickness: 25 μm, HC thickness: 7 μm) was placed on one side of the obtained absorption type polarizing film, and a cycloolefin resin film (thickness: 13 μm) was placed on the other side. were laminated together as a protective layer. Specifically, the curable adhesive was coated to a total thickness of about 1 μm, and then bonded together using a roll machine. Thereafter, UV light was irradiated from the TAC film side to cure the adhesive.
Thereby, a polarizing film A having the structure of [TAC film (protective layer)/absorption type polarizing film/COP film (protective layer)] was obtained.

[Production Example 3: Production of λ/4 member A]
Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100°C. Bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol), spiroglycol (SPG) 42 .28 parts by mass (0.139 mol), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19×10 ⁻² parts by mass (6.78×10 −2 of calcium acetate monohydrate as a catalyst ^{). 5} mol) was prepared. After the inside of the reactor was replaced with nitrogen under reduced pressure, it was heated with a heating medium, and when the internal temperature reached 100°C, stirring was started. 40 minutes after the start of temperature rise, the internal temperature was controlled to reach 220°C, and at the same time, pressure reduction was started to maintain this temperature, and the pressure was reduced to 13.3 kPa in 90 minutes after reaching 220°C. Phenol vapor produced as a by-product during the polymerization reaction was led to a reflux condenser at 100°C, a small amount of monomer component contained in the phenol vapor was returned to the reactor, and uncondensed phenol vapor was led to a condenser at 45°C for recovery. After nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Next, temperature increase and pressure reduction in the second reactor were started, and the internal temperature was 240° C. and the pressure was 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined stirring power was reached. When a predetermined power was reached, nitrogen was introduced into the reactor to restore the pressure, the produced polyester carbonate resin was extruded into water, and the strands were cut to obtain pellets.

After vacuum drying the obtained polyester carbonate resin (pellets) at 80°C for 5 hours, a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder temperature setting: 250°C) and a T-die (width 200mm, setting temperature: 250°C) were used. A long resin film with a thickness of 135 μm was produced using a film forming apparatus equipped with a chill roll (set temperature: 120 to 130° C.), a winder and a winder. The obtained elongated resin film was stretched in the width direction at a stretching temperature of 143° C. and a stretching ratio of 2.8 times. Thereby, a stretched film (λ/4 member A) having a thickness of 47 μm was obtained. Re(590) of λ/4 member A was 143 nm, Re(450)/Re(550) was 0.86, and the Nz coefficient was 1.12.

[Production Example 4: Production of positive C plate A]
20 parts by weight of a side chain type liquid crystal polymer represented by the following chemical formula (1) (numbers 65 and 35 in the formula indicate mol% of monomer units, and are conveniently expressed as a block polymer: weight average molecular weight 5000), 80 parts by weight of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF, trade name Paliocolor LC242) and 5 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name Irgacure 907) were dissolved in 200 parts by weight of cyclopentanone. A liquid crystal coating solution was prepared. Then, the coating solution was applied to a PET substrate subjected to vertical alignment treatment using a bar coater, and then heated and dried at 80° C. for 4 minutes to align the liquid crystal. By irradiating this liquid crystal layer with ultraviolet rays and curing the liquid crystal layer, a positive C plate A having a thickness of 4 μm and an Rth (550) of −100 nm was formed on the base material.

[Manufacture example 5: Production of protective member A]
A hard coat layer forming material shown below was applied to an acrylic film (40 μm thick) having a lactone ring structure, and the applied layer was dried to form a 0.5 μm thick hard coat layer. Next, the coating solution for forming an antireflection layer shown below was applied to the surface of the hard coat layer, heated at 80°C for 1 minute, and the heated coating layer was exposed to ultraviolet rays at a cumulative light intensity of 300 mJ/cm ² using a high-pressure mercury lamp. The coating layer was cured by irradiation to form an antireflection layer with a thickness of 0.1 μm. As a result, a protective member A having a structure of [acrylic film/hard coat layer/antireflection layer] was obtained.

(Material for forming hard coat layer)
By adding 0.5% by weight of a leveling agent to acrylic resin raw material (manufactured by Dainippon Ink Co., Ltd., product name: GRANDIC PC1071), and further diluting with ethyl acetate so that the solid content concentration is 50% by weight, A material for forming a hard coat layer was prepared. The leveling agent is a copolymer copolymerized at a molar ratio of dimethylsiloxane: hydroxypropylsiloxane: 6-isocyanatehexylisocyanuric acid: aliphatic polyester = 6.3:1.0:2.2:1.0. It is.

(Coating liquid for forming antireflection layer)
100 parts by weight of polyfunctional acrylate whose main component is pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., product name "Viscoat #300", solid content 100% by weight), hollow nano silica particles (JGC Catalysts & Chemicals Co., Ltd.) 150 parts by weight, solid nano silica particles (manufactured by Nissan Chemical Industries, Ltd., trade name "MEK-2140Z-AC", solid content 20% by weight, weight average particle diameter 75 nm), solid content 30% 50 parts by weight (wt%, weight average particle diameter 10 nm), 12 parts by weight of a fluorine element-containing additive (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solid content 20 wt%), and a photopolymerization initiator ( 3 parts by weight of "OMNIRAD907" (trade name, manufactured by BASF, solid content: 100% by weight) were mixed. To the mixture, a mixed solvent of TBA (tertiary butyl alcohol), MIBK (methyl isobutyl ketone) and PMA (propylene glycol monomethyl ether acetate) mixed in a weight ratio of 60:25:15 was added as a diluting solvent to dissolve the entire solid. The coating solution for forming an antireflection layer was prepared by stirring the mixture so that the amount thereof was 4% by weight.

[Production Example 6: Preparation of adhesive layer A]
In a four-neck flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, add 80.3 parts of butyl acrylate, 16 parts of phenoxyethyl acrylate, 3 parts of N-vinyl-2-pyrrolidone (NVP), and acrylic acid. A monomer mixture containing 0.3 parts and 0.4 parts of 4-hydroxybutyl acrylate was charged. Further, to 100 parts of the above monomer mixture (solid content), 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate, and nitrogen gas was added while stirring gently. The atmosphere was replaced with nitrogen. Next, a polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55° C. to prepare an acrylic polymer solution. The weight average molecular weight of the acrylic polymer was 1.5 million. An acrylic adhesive solution was prepared by adding 0.3 parts of benzoyl peroxide (BPO: Niper BMT manufactured by NOF Corporation) as a crosslinking agent to 100 parts of the solid content of the obtained acrylic polymer solution.
The obtained adhesive composition was applied to the release-treated layer surface of a release liner (manufactured by Toray Industries, Inc., Therapel) and dried at 155° C. for 3 minutes to form an adhesive layer with a thickness of 20 μm.

[Example 1]
The above-mentioned adhesive layer A was attached to the COP protective layer side surface of the above-mentioned polarizing film A together with a release liner.
On the other hand, positive C plate A was bonded to λ/4 member A via an ultraviolet curable adhesive (thickness after curing: 1 μm), and then the base material was peeled off to obtain a retardation member.
The obtained retardation member was bonded to the TAC film side surface of polarizing film A via an acrylic adhesive layer (thickness: 15 μm). At this time, the surface of the retardation member on the λ/4 member A side should be on the polarizing film A side, and the angle between the absorption axis of the absorption type polarizing film and the slow axis of the λ/4 member A should be 45°. I pasted them together so that
Next, the protective member A was bonded to the surface of the retardation member via an acrylic adhesive layer (thickness: 12 μm). At this time, the protective member A was attached so that the surface on the acrylic film side was on the retardation member side (in other words, so that the antireflection layer was on the outermost surface). As described above, an optical laminate A having the configuration of [release liner/adhesive layer A/polarizing film A/λ/4 member A/positive C plate A/protective member A] was obtained.
Next, the release liner was peeled off from the surface protection film D, and it was bonded to the protective member A side surface (antireflection layer surface) of the optical laminate A as an inner surface protection film. Next, the release liner was peeled off from the surface protection film A, and was bonded to the base material side surface of the surface protection film D as an outer surface protection film. Thereby, an optical laminate with a surface protection film having the structure of [Optical laminate A/Surface protection film D/Surface protection film A] was obtained.

[Example 2]
An optical laminate with a surface protection film having the structure of [optical laminate A/surface protection film D/surface protection film B] was prepared in the same manner as in Example 1 except that surface protection film B was used as the outer surface protection film. I got a body.

[Comparative example 1]
An optical laminate with a surface protection film having the structure of [optical laminate A/surface protection film D/surface protection film C] was prepared in the same manner as in Example 1 except that surface protection film C was used as the outer surface protection film. I got a body.

<Bubble evaluation>
The optical laminates with surface protection films obtained in the above Examples and Comparative Examples were cut into a size of 371.87 mm x 236.58 mm and used as evaluation samples. The evaluation sample was set in an automatic optical inspection device, and a reflective visual inspection was performed to count the number of air bubbles present between the inner surface protection film and the outer surface film. Table ² shows the number of bubbles generated per 1 m2.

<Peeling stability evaluation>
The optical laminates with surface protection films obtained in Examples and Comparative Examples were placed on a laboratory bench with the surface protection film side up at room temperature, and peeled at a peeling angle of 180° and a peeling speed of 300 mm/min. The outer surface protective film was peeled off, and evaluation was made according to the following criteria. The results are shown in Table 2.
Good: Only the outer surface protection film was peeled off. Bad: Both the outer and inner surface protection films were peeled off.

As shown in Table 2, the optical laminate with a surface protection film of the example suppresses the generation of air bubbles between the inner surface protection film and the outer surface protection film, and therefore, when subjected to defect inspection. , it can be seen that erroneous detection of air bubbles as a defect is prevented. In addition, an optical laminate with a surface protection film having such a structure can be inspected for defects multiple times with the surface protection film attached, and the surface of the optical laminate can be inspected for defects until it is used for final assembly. can be suitably protected. Furthermore, the optical laminate with a surface protection film of the example has excellent peeling stability.

The present invention is not limited to the above embodiments, and various modifications are possible. For example, it can be replaced with a configuration that is substantially the same as the configuration shown in the above embodiment, a configuration that has the same effect, or a configuration that can achieve the same objective.

The optical laminate with a protective film according to the embodiment of the present invention can be used, for example, to manufacture goggles with a display such as VR goggles.

2 Display system 4 Lens section 10 Polarizing member 12 Display element 14 Reflective polarizing member 16 First lens section 18 Half mirror 20 First retardation member 22 Second retardation member 24 Second lens section 100 Optical laminate 110 First surface Protective film 120 Second surface protection film 200 Optical laminate with surface protection film

Claims

An optical laminate including at least one optical member and used for goggles with a display;
A first surface protection film and a second surface protection film, which are attached in this order outward to one surface of the optical laminate;
An optical laminate with a surface protection film, comprising:
The first surface protection film has a first base material and a first adhesive layer laminated on the first base material,
The second surface protection film has a second base material and a second adhesive layer laminated on the second base material,
The thickness of the second adhesive layer is 8 μm or more,
A surface in which a peeling force P1 of the first surface protection film to the optical laminate and a peeling force P2 of the second surface protection film to the first surface protection film satisfy the relationship P2/P1≦0.8. Optical laminate with protective film.
The optical laminate with a surface protection film according to claim 1, wherein a peeling force P2 of the second surface protection film with respect to the first surface protection film is 0.5 N/50 mm or less.
The optical laminate with a surface protection film according to claim 1, wherein the first surface protection film and the second surface protection film each have a total light transmittance of 85% or more.
According to claim 1, the ratio (L2/L1) of the total light transmittance L1 of the first surface protection film to the total light transmittance L2 of the second surface protection film is 0.8 to 1.2. Optical laminate with surface protection film.
The optical laminate includes:
(1) An absorption type polarizing member, a first retardation member, and a protective member are provided in this order toward the first surface protection film, or
(2) A second retardation member and a protection member are provided in this order toward the first surface protection film, or (3) a reflective polarizing member and a protection member are provided in the first surface protection film. have in this order towards,
The optical laminate with a surface protection film according to claim 1.
The protective member includes a surface treatment layer,
The optical laminate with a surface protection film according to claim 5, wherein the first surface protection film is attached to the surface treatment layer.
the surface treatment layer includes an antireflection layer,
The optical laminate with a surface protection film according to claim 6, wherein the first surface protection film is attached to the antireflection layer.
The optical laminate with a surface protection film according to claim 1, wherein the optical laminate has an adhesive layer on a surface opposite to the side to which the first surface protection film and the second surface protection film are attached. body.
A method of manufacturing a display system, the method comprising:
Inspecting the optical laminate with a surface protection film according to any one of claims 1 to 8 for defects;
Another member is attached to the side opposite to the side to which the first surface protection film and the second surface protection film are attached of the optical laminate with a surface protection film, thereby producing a secondary laminate with a surface protection film. to obtain,
Peeling the second surface protection film from the surface protection film-attached secondary laminate;
inspecting the secondary laminate with the surface protection film for defects; and peeling off the first surface protection film from the secondary laminate with the surface protection film to obtain a secondary laminate.
In this order,
A manufacturing method, wherein the display system is goggles with a display.