WO2023176631A1 - Optical laminate, lens part, and display method - Google Patents

Abstract

Provided is an optical laminate capable of reducing the weight of VR goggles and improving visibility. An optical laminate (200) according to an embodiment of the present invention comprises, in the following order: a laminate film (32) having a base material and a surface treated layer; a reflective polarization member (14); an absorptive polarization member (28); and a retardation member (30), wherein the base material of the laminate film includes a (meth)acrylic resin, and the laminate smoothness is no more than 0.70 acrmin.

Description

Optical laminate, lens part and display method

The present invention relates to an optical laminate, a lens part, and a display method.

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. Since VR goggles are being considered for use in a variety of situations, it is desired that they be made lighter and have improved visibility. Weight reduction can be achieved, for example, by making the lenses used in VR goggles thinner. On the other hand, there is also a desire for the development of optical members suitable for display systems using thin lenses.

JP2021-103286A

In view of the above, the main purpose of the present invention is to provide an optical laminate that can reduce the weight of VR goggles and improve visibility.

1. An optical laminate according to an embodiment of the present invention includes a laminate film having a base material and a surface treatment layer, a reflective polarizing member, an absorptive polarizing member, and a retardation member in this order, The base material contains a (meth)acrylic resin, and the smoothness of the laminate is 0.70 arcmin or less.
2. In the optical laminate described in 1 above, the base material of the laminate film may have a surface smoothness of 0.7 arcmin or less.
3. In the optical laminate described in 1 or 2 above, the surface smoothness of the laminate film may be 0.5 arcmin or less.
4. In the optical laminate according to any one of 1 to 3 above, the surface treatment layer of the laminate film may have an antireflection function.
5. In the optical laminate according to any one of 1 to 4 above, the base material of the laminate film may have a transmittance of 20% or less at a wavelength of 400 nm.
6. In the optical laminate according to any one of 1 to 5 above, the absorptive polarizing member may include a protective layer and an absorptive polarizing film.
7. The lens unit according to the embodiment of the present invention is a lens unit used in a display system that displays an image to a user, and is a lens unit that emits light forward from a display surface of a display element that represents an image, and includes a polarizing member and a first an optical laminate according to any one of 1 to 6 above that reflects light that has passed through the λ/4 member; and a first lens portion disposed on an optical path between the display element and the optical laminate. , the reflective polarizing member is disposed between the display element and the first lens part, transmits the light emitted from the display element, and transmits the light reflected by the reflective polarizing member of the optical laminate. a second lens portion disposed in front of the optical laminate, and a second λ/4 member disposed on the optical path between the half mirror and the optical laminate. and.
8. A display method according to an embodiment of the present invention includes a step of causing light representing an image emitted through a polarizing member and a first λ/4 member to pass through a half mirror and a first lens portion; A step of causing the light that has passed through the first lens portion to pass through a second λ/4 member, and a step of transmitting the light that has passed through the second λ/4 member to the optical system according to any one of 1 to 6 above. reflecting the light reflected by the reflective polarizing member and the half mirror of the optical laminate toward the half mirror by the second λ/4 member; and a step of allowing the light transmitted through the reflective polarizing member to pass through a second lens portion.

According to the optical laminate according to the embodiment of the present invention, it is possible to reduce the weight of VR goggles and improve visibility.

1 is a schematic diagram showing a general configuration of a display system according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of details of a lens section of the display system shown in FIG. 1. FIG. 3 is a schematic cross-sectional view showing a modification of the optical laminate shown in FIG. 2. FIG. FIG. 2 is a schematic perspective view showing an example of a multilayer structure included in a reflective polarizing film.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. 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 only an example and does not limit the interpretation of the present invention. isn't it. Further, in the drawings, the same or equivalent elements are denoted by the same reference numerals, and overlapping explanations may be omitted.

(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. Therefore, for example, "45°" means ±45°.

FIG. 1 is a schematic diagram showing the general configuration of a display system according to one embodiment of the present invention. FIG. 1 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.

A half mirror or components disposed in front of the first lens part (in the illustrated example, the half mirror 18, the first lens part 16, the second retardation member 22, the reflective polarizing member 14, and the second lens part 24) ) may be collectively referred to as a lens section (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. The light emitted from the display surface 12a passes through a polarizing member (typically, a polarizing film) 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.

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 included in the display element 12 and the reflection axis of the reflective polarizing member 14 may be arranged substantially parallel to each other, or may be arranged substantially perpendicular to each other. The angle between the absorption axis of the polarizing member 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° to 50°. It may be 48° or 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°.

The in-plane retardation Re (550) of the first λ/4 member 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. 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. The first λ/4 member preferably satisfies the relationship Re(450)<Re(550)<Re(650). 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 in-plane retardation Re (550) of the second λ/4 member 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. 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. The second λ/4 member preferably satisfies the relationship Re(450)<Re(550)<Re(650). 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.

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.

FIG. 2 is a schematic cross-sectional view showing an example of details of the lens section of the display system shown in FIG. 1. Specifically, FIG. 2 shows a first lens part, a second lens part, and members disposed between them. The lens part 4 includes a first lens part 16 , a first laminated part 100 provided adjacent to the first lens part 16 , a second lens part 24 , and a second laminated part 100 provided adjacent to the second lens part 24 . A laminated portion 200 is provided. In the example shown in FIG. 2, the first laminated part 100 and the second laminated part 200 are arranged apart from each other. Although not shown, a half mirror may be provided integrally with the first lens section 16. Hereinafter, the second laminate section may be referred to as an optical laminate.

The first laminated part 100 includes a second retardation member 22 and an adhesive layer (for example, an adhesive layer) 41 disposed between the first lens part 16 and the second retardation member 22, and the adhesive layer 41, it is integrally provided to the first lens portion 16. The first laminated portion 100 further includes a first protection member 31 disposed in front of the second retardation member 22. The first protection member 31 is laminated on the second retardation member 22 via an adhesive layer (for example, a pressure-sensitive adhesive layer) 42, and is disposed adjacent to the second retardation member 22. The first protection member 31 may be located on the outermost surface of the first laminated portion 100. Note that in this specification, adjacent includes not only directly adjacent but also adjacent via an adhesive layer.

In the example shown in FIG. 2, the second retardation member 22 includes, in addition to the second λ/4 member (first retardation layer) 22a, a member (the second retardation layer) having a refractive index characteristic of nz>nx≧ny. (two retardation layers) 22b. The second retardation member 22 has a laminated structure of a first retardation layer 22a and a second retardation layer 22b. By using the member 22b that exhibits the relationship nz>nx≧ny, light leakage (for example, light leakage in an oblique direction) can be prevented. As shown in FIG. 2, in the second retardation member 22, it is preferable that the second λ/4 member 22a is located in front of the member 22b which exhibits the relationship nz>nx≧ny.

The second λ/4 member (first retardation layer) 22a and the member (second retardation layer) 22b exhibiting the relationship nz>nx≧ny are laminated with an adhesive layer 51 in between. The second retardation member 22 includes a first retardation layer 22a, an adhesive layer 51, and a second retardation layer 22b.

Preferably, the second λ/4 member 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 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 second 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. Note that the details of the polycarbonate resin that can be suitably used for the second λ/4 member and the method for forming the second λ/4 member can be found in, for example, JP-A No. 2014-10291 and JP-A No. 2014-26266. , 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 second 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 second λ/4 member, rod-shaped liquid crystal compounds are typically aligned in the slow axis direction of the second 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 second 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.

The retardation Rth (550) in the thickness direction of the member (second retardation layer) whose refractive index characteristics exhibit the relationship of nz>nx≧ny is preferably -260 nm to -10 nm, more preferably -230 nm to -230 nm. -15 nm, more preferably -215 nm to -20 nm. In one embodiment, the second retardation layer is a so-called positive C plate whose refractive index exhibits the relationship nx=ny. 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. For example, cases where Re(550) is less than 10 nm are also included. In another embodiment, the second retardation layer has a refractive index that exhibits a relationship of nx>ny. In this case, the in-plane retardation Re (550) of the second retardation layer is preferably 10 nm to 150 nm, more preferably 10 nm to 80 nm.

The member whose refractive index characteristics exhibit the relationship nz>nx≧ny may be formed of any suitable material. Preferably, it 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 such liquid crystal compounds and film forming methods include the liquid crystal compounds and forming methods described in [0020] to [0042] of JP-A No. 2002-333642. In this case, the thickness is preferably 0.1 μm to 5 μm, more preferably 0.5 μm to 4 μm.

As another preferred specific example, the member whose refractive index characteristics exhibit the relationship of nz>nx≧ny may be a retardation film formed from a fumaric acid diester resin described in JP-A No. 2012-32784. . In this case, the thickness is preferably 5 μm to 50 μm, more preferably 10 μm to 35 μm.

The first protection member typically includes a base material. The thickness of the base material is preferably 5 μm to 80 μm, more preferably 10 μm to 50 μm, and still more preferably 15 μm to 40 μm. The surface smoothness of the base material is preferably 0.7 arcmin or less, more preferably 0.6 arcmin or less, still more preferably 0.5 arcmin or less, particularly preferably 0.45 arcmin or less. In the above display system, the image can be enlarged in the lens portion (for example, by a convex lens), and the smoothness of the optical laminate can greatly affect visibility. Since the base material of the protective member that can be located on the outermost surface of the laminated portion has excellent smoothness, the smoothness of the optical laminate obtained using the base material can also be extremely excellent. Moreover, according to such an optical laminate, significantly excellent visibility can be realized in the above-mentioned display system. For example, a clear image without distortion can be realized. The surface smoothness of the base material is, for example, 0.1 arcmin or more. Note that surface smoothness can be measured by focusing irradiation light on the surface of the target.

The base material may be composed 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. Here, (meth)acrylic refers to acrylic and/or methacrylic. In one embodiment, the base material is preferably made of (meth)acrylic resin. By employing a (meth)acrylic resin, a base material with excellent smoothness (for example, satisfying the above-mentioned surface smoothness) can be formed into a film by extrusion molding. Then, a protective member with excellent smoothness can be obtained.

For example, the base material may have a transmittance of 20% or less at a wavelength of 400 nm.

The first protective member is preferably composed of a laminated film having a base material and a surface treatment layer formed on the base material. The thickness of the laminated film is preferably 10 μm to 80 μm, more preferably 15 μm to 60 μm, even more preferably 20 μm to 45 μm. The thickness of the surface treatment layer is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and still more preferably 2 μm to 5 μm.

The surface treatment layer typically includes a hard coat layer. The hard coat layer is typically formed by applying a hard coat layer forming material to a base material and curing the applied layer. The hard coat layer forming material typically contains a curable compound as a layer forming component. Examples of the curing mechanism of the curable compound include a thermosetting type and a photocuring type. Examples of the curable compound include monomers, oligomers, and prepolymers. Preferably, a polyfunctional monomer or oligomer is used as the curable compound. Examples of polyfunctional monomers or oligomers include monomers or oligomers having two or more (meth)acryloyl groups, urethane (meth)acrylate or urethane (meth)acrylate oligomers, epoxy monomers or oligomers, and silicone monomers or oligomers. can be mentioned.

The thickness of the hard coat layer is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and even more preferably 2 μm to 5 μm.

The surface treatment layer preferably includes a functional layer. The functional layer preferably functions as an antireflection layer. In a preferred embodiment, the surface treatment layer includes the hard coat layer and the antireflection layer in this order from the base material side. The thickness of the functional layer is preferably 0.05 μm to 10 μm, more preferably 0.1 μm to 5 μm, and even more preferably 0.1 μm to 2 μm.

The first protective 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 first laminated portion. The surface treatment layer may have any suitable function. The surface treatment layer preferably has an antireflection function, for example, from the viewpoint of suppressing optical loss at the interface with air and improving visibility. In one embodiment, the first protective member preferably has a maximum value of the 5° specular reflectance spectrum in the wavelength range of 420 nm to 680 nm of 2.0% or less, more preferably 1.2% or less. It is more preferably 1.0% or less, particularly preferably 0.8% or less. Here, to measure the 5° specular reflectance, use an adhesive to attach the measurement target to a black acrylic plate to prepare a measurement sample, and use a spectrophotometer (manufactured by Hitachi High-Technologies, trade name: "U-4100"), and the angle of incidence of light on the measurement sample is 5°.

The surface smoothness of the first protective member is preferably 0.5 arcmin or less, more preferably 0.4 arcmin or less. Substantially, the surface smoothness of the first protection member is, for example, 0.1 arcmin or more.

The second laminated portion 200 includes a reflective polarizing member 14 and an adhesive layer (for example, an adhesive layer) disposed between the reflective polarizing member 14 and the second lens portion 24. The second laminated section 200 further includes, for example, an absorptive polarizing member 28 disposed between the reflective polarizing member 14 and the second lens section 24 from the viewpoint of improving visibility. The absorptive polarizing member 28 is laminated in front of the reflective polarizing member 14 with an adhesive layer (for example, an adhesive layer) 44 interposed therebetween. The absorption type polarizing member 28 includes at least an absorption type polarizing film. As shown in FIG. 2, when the absorption type polarizing member 28 does not include any member (for example, a protective layer) other than the absorption type polarizing film, the absorption type polarizing member 28 can correspond to an absorption type polarizing film. Then, the absorptive polarizing film may be placed adjacent to the reflective polarizing member 14. The reflection axis of the reflective polarizing member 14 and the absorption axis of the absorbing polarizing film included in the absorbing polarizing member 28 may be arranged substantially parallel to each other, and the transmission axis of the reflective polarizing member 14 and the absorption axis of the absorbing polarizing film included in the absorbing polarizing member 28 may be arranged substantially parallel to each other. The transmission axes of the absorbing polarizing films may be arranged substantially parallel to each other. By laminating them through an adhesive layer, the reflective polarizing member 14 and the absorbing polarizing member 28 are fixed, and it is possible to prevent misalignment of the axis arrangement between the reflective axis and the absorption axis (the transmission axis and the transmission axis). . Further, it is possible to suppress the adverse effects of an air layer that may be formed between the reflective polarizing member 14 and the absorbing polarizing member 28.

The second laminated section 200 further includes a second protection member 32 disposed behind the reflective polarizing member 14. The second protection member 32 is laminated on the reflective polarizing member 14 via an adhesive layer (for example, an adhesive layer) 43. The second protection member 32 may be located on the outermost surface of the second laminated portion 200. The first protection member 31 and the second protection member 32 are arranged to face each other with a space interposed therebetween. Like the first protection member, the second protection member may typically be a laminated film having a base material and a surface treatment layer. In this case, the surface treatment layer may be located on the outermost surface of the second laminated portion. Regarding the details of the second protection member, the same explanation as that for the first protection member can be applied. Specifically, the same explanations as for the first protection member can be applied to the reflection characteristics, effects, smoothness, thickness, and constituent materials of the second protection member.

In the second laminate section 200, the selection of the second protective member 32 can greatly contribute to improving the smoothness of the entire laminate section (optical laminate). For example, when the base material of the second protection member 32 is made of (meth)acrylic resin, it can greatly contribute to improving the smoothness of the entire laminated portion (optical laminate).

In the example shown in FIG. 2, the second laminated section 200 further includes a third retardation member 30 disposed between the absorptive polarizing member 28 and the second lens section 24. The third retardation member 30 is laminated on the absorption type polarizing member 28 via an adhesive layer (for example, an adhesive layer) 45. Further, the third retardation member 30 is laminated on the second lens portion 24 via an adhesive layer (for example, an adhesive layer) 46, and the second laminated portion 200 is integrally provided on the second lens portion 24. There is. The third retardation member 30 includes, for example, a third λ/4 member. The angle between the absorption axis of the absorption type polarizing member 28 and the slow axis of the third λ/4 member included in the third retardation member 30 is, for example, 40° to 50°, and 42° to 48°. The angle may be approximately 45°. By providing such a member, for example, reflection of external light from the second lens portion 16 side can be prevented. From the viewpoint of improving smoothness, it is preferable that the third retardation member 30 does not include any member (for example, an adhesive layer or a retardation layer) other than the third λ/4 member. In this case, the third retardation member 30 may correspond to the third λ/4 member.

FIG. 3 is a schematic cross-sectional view showing a modification of the optical laminate (second laminate part) shown in FIG. 2. In the example shown in FIG. 3, the absorption type polarizing member 28 includes a protective layer 28b in addition to the absorption type polarizing film 28a. The absorption type polarizing film 28a and the protective layer 28b are laminated with an adhesive layer 52 in between. The absorption type polarizing member 28 includes an absorption type polarizing film 28a, an adhesive layer 52, and a protective layer 28b. In the illustrated example, the protective layer 28b is arranged between the absorption type polarizing film 28a and the reflective polarizing member 14, but it may be arranged between the absorption type polarizing film 28a and the third retardation member 30. . Further, although not shown, protective layers may be laminated on both sides of the absorption type polarizing film with adhesive layers interposed therebetween.

The reflective polarizing member can transmit polarized light parallel to its transmission axis (typically, linearly polarized light) while maintaining its polarized state, and can reflect light in other polarized states. The reflective polarizing member is typically composed of a film having a multilayer structure (sometimes referred to as a reflective polarizing film). In this case, the thickness of the reflective polarizing member is, for example, 10 μm to 150 μm, preferably 20 μm to 100 μm, and more preferably 30 μm to 60 μm.

FIG. 4 is a schematic perspective view showing an example of a multilayer structure included in a reflective polarizing film. The multilayer structure 14a has layers A having birefringence and layers B having substantially no birefringence alternating. The total number of layers making up the multilayer structure may be between 50 and 1000. For example, the refractive index nx in the x-axis direction of the A layer is larger than the refractive index ny in the y-axis direction, and the refractive index nx in the x-axis direction and the refractive index ny in the y-axis direction of the B layer are substantially the same, The refractive index difference between layer A and layer B is large in the x-axis direction and substantially zero in the y-axis direction. As a result, the x-axis direction can become the reflection axis, and the y-axis direction can become the transmission axis. The refractive index difference between layer A and layer B in the x-axis direction is preferably 0.2 to 0.3.

The above layer A is typically made of a material that exhibits birefringence when stretched. Such materials include, for example, naphthalene dicarboxylic acid polyesters (eg, polyethylene naphthalate), polycarbonates, and acrylic resins (eg, polymethyl methacrylate). The B layer is typically made of a material that does not substantially exhibit birefringence even when stretched. Examples of such materials include copolyesters of naphthalene dicarboxylic acid and terephthalic acid. The multilayer structure may be formed by a combination of coextrusion and stretching. For example, after extruding the material constituting layer A and the material constituting layer B, they are multilayered (for example, using a multiplier). The obtained multilayer laminate is then stretched. The x-axis direction in the illustrated example may correspond to the stretching direction.

Commercially available reflective polarizing films include, for example, 3M's product names "DBEF" and "APF" and Nitto Denko's product name "APCF".

The cross transmittance (Tc) of the reflective polarizing member (reflective polarizing film) may be, for example, 0.01% to 3%. The single transmittance (Ts) of the reflective polarizing member (reflective polarizing film) is, for example, 43% to 49%, preferably 45% to 47%. The degree of polarization (P) of the reflective polarizing member (reflective polarizing film) can be, for example, 92% to 99.99%.

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 visual field (C light source) according to JIS Z 8701 and subjected to visibility correction.
Polarization degree P (%) = {(Tp-Tc)/(Tp+Tc)} ^1/2 ×100

The absorption type polarizing member may typically include a resin film (sometimes referred to as an absorption type polarizing film) containing a dichroic substance. 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 method for manufacturing 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 orthogonal transmittance (Tc) of the absorption type polarizing member (absorption type polarizing film) is preferably 0.5% or less, more preferably 0.1% or less, and still more preferably 0.05% or less. be. The single transmittance (Ts) of the absorption type polarizing member (absorption type polarizing film) is, for example, 41.0% to 45.0%, preferably 42.0% or more. The degree of polarization (P) of the absorption type polarizing member (absorption type polarizing film) is, for example, 99.0% to 99.997%, preferably 99.9% or more.

The protective layer that may be included in the absorption type polarizing member may be composed of any suitable film. Examples of the main component of the film constituting the protective layer include cellulose resins such as triacetylcellulose (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 protective layer is preferably 5 μm to 80 μm, more preferably 10 μm to 50 μm, even more preferably 15 μm to 40 μm. The surface smoothness of the protective layer is preferably 0.7 arcmin or less, more preferably 0.6 arcmin or less, and still more preferably 0.5 arcmin or less.

The adhesive layer 52 that may be included in the absorptive polarizing member 28 may be formed of any suitable adhesive. As the adhesive, preferably a water-based adhesive is used. By using a water-based adhesive, an extremely thin adhesive layer can be formed. Furthermore, by using a water-based adhesive, the resulting absorption type polarizing member can have excellent smoothness. The thickness of the adhesive layer that may be included in the absorption type polarizing member is preferably 1 μm or less, more preferably 0.5 μm or less, and still more preferably 0.2 μm or less. With such a thickness, the laminated portion can have excellent smoothness. The thickness of the adhesive layer that may be included in the absorbent member is, for example, 0.01 μm or more from the viewpoint of adhesiveness and the like.

The in-plane retardation Re (550) of the third λ/4 member 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 third 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 third 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 third λ/4 member preferably exhibits a refractive index characteristic of nx>ny≧nz. The Nz coefficient of the third λ/4 member is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably is 0.9 to 1.3.

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

The thickness of the adhesive layer used for laminating each of the above members can be set to any appropriate thickness. The thickness of each adhesive layer used for laminating the above members is preferably 3 μm or more and 20 μm or less, and may be 15 μm or less, 10 μm or less, or 7 μm or less. With such a thickness, the degree of unevenness on the surface of the adhesive layer can be suppressed, and the laminated portion can have excellent smoothness.

For example, the adhesive layer has a linear expansion coefficient α1 when the temperature is raised from 20°C to 30°C and a linear expansion coefficient α2 when the temperature is lowered from 30°C to 20°C of 0.8≦α1/α2≦1.2. It is preferable that the following relationship be satisfied, preferably 0.85≦α1/α2≦1.15, more preferably 0.9≦α1/α2≦1.1. By using an adhesive layer that satisfies such a relationship, an optical laminate with excellent stability of optical properties can be obtained even under harsh environments. α1 may be, for example, 5.0×10 ⁻⁴ /°C or more and 7.0×10 ⁻⁴ /°C or less. α2 may be, for example, 5.0×10 ⁻⁴ /°C or more and 7.0×10 ⁻⁴ /°C or less, and for example, 6.0×10 ⁻⁴ /°C or more and 7.0×10 ⁻⁴ /°C or less. .

For example, the adhesive layer has a linear expansion coefficient β1 when the temperature is raised from 60°C to 70°C and a linear expansion coefficient β2 when the temperature is lowered from 70°C to 60°C of 1.0≦β1/β2≦1.5. The following relationship is satisfied, preferably 1.05≦β1/β2≦1.45, more preferably 1.1≦β1/β2≦1.4. By using an adhesive layer that satisfies such a relationship, an optical laminate with excellent stability of optical properties can be obtained even under harsh environments. β1 may be, for example, 8.0×10 ⁻⁴ /°C or more and 9.0×10 ⁻⁴ /°C or less. β2 may be, for example, 6.0×10 ⁻⁴ /°C or more and 7.0×10 ⁻⁴ /°C or less.

The adhesive layer 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.

For example, the adhesive layer can be formed by applying an adhesive composition containing a base resin, additives such as a crosslinking agent, and a solvent, and drying. The adhesive composition may be applied directly to an adherend, or may be applied to a separately prepared substrate such as a base film. Drying is typically performed by heating.

The laminate smoothness of the optical laminate 200 is 0.70 arcmin or less, preferably 0.65 arcmin or less, and more preferably 0.55 arcmin or less. When the optical laminate satisfies such laminate smoothness, it is possible to suppress the generation of diffused light and to suppress images from becoming unclear. The laminate smoothness of the optical laminate 200 is, for example, 0.1 arcmin or more. Note that the smoothness of the laminate can be obtained by irradiating an object with irradiation light and detecting the degree of reflection and transmission of each member constituting the object (the laminate). The thickness variation (σ) of the optical laminate 200 is preferably less than 0.001.

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, retardation value, and surface smoothness are values measured by the following measuring method. Furthermore, unless otherwise specified, "parts" and "%" are based on weight.
<Thickness>
The thickness of 10 μm or less was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name “JSM-7100F”). Thickness exceeding 10 μm was measured using a digital micrometer (manufactured by Anritsu Corporation, product name “KC-351C”).
<Phase difference value>
The phase difference value at each wavelength at 23° C. was measured using a Mueller matrix polarimeter (manufactured by Axometrics, product name “Axoscan”).
<Surface smoothness>
Surface smoothness was measured using a scanning white interferometer (manufactured by Zygo, product name "NewView9000"). Specifically, a measurement sample is placed on a measurement table with a vibration-proof table, interference fringes are generated using a single white LED illumination, and an interference objective lens (1.4x) with a reference plane is placed in the Z direction (thickness The smoothness (surface smoothness) of the outermost surface of the object to be measured in a field of view of 12.4 mm□ was selectively obtained by scanning in the 12.4 mm□ field of view.
When the measurement target was an adhesive layer, the adhesive layer was attached to a microslide glass (manufactured by Matsunami Glass Industries Co., Ltd., product name "S200200"), and the smoothness of the exposed adhesive surface was measured. If the object to be measured is a film, an acrylic adhesive layer with a thickness of 5 μm and less unevenness is formed on the glass, and the film to be measured is laminated on this adhesive surface to prevent foreign objects, air bubbles, and deformation lines from entering. The smoothness of the surface opposite to the adhesive layer was measured. Incidentally, the surface smoothness of the acrylic pressure-sensitive adhesive layer having a thickness of 5 μm and having few irregularities was 0.30 arcmin.
Regarding the analysis, the value obtained by doubling the angle index "Slope magnitude RMS" (corresponding to 2σ) was defined as surface smoothness (unit: arcmin).

[Example 1]
(Preparation of absorption type polarizing film)
A long roll of polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, trade name "PE3000") with a thickness of 30 μm was simultaneously uniaxially stretched in the longitudinal direction so as to be 5.9 times larger in the longitudinal direction using a roll stretching machine. After performing swelling, dyeing, crosslinking, and washing treatments in this order, a drying treatment was finally performed to produce an absorption type polarizing film with a thickness of 12 μm.
In the above 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 polarizing film obtained was 45.0%. However, it was stretched 1.4 times. Next, a two-stage crosslinking treatment was adopted for the crosslinking treatment, and the first crosslinking treatment was performed in an aqueous solution containing boric acid and potassium iodide at 40° C. and 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. Next, washing treatment was performed with 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, it was dried at 70° C. for 5 minutes to obtain an absorption type polarizing film.

(Preparation of water-based adhesive)
Dissolve 50 parts by weight of methylolmelamine in pure water per 100 parts by weight of PVA resin having an acetoacetyl group (average degree of polymerization 1200, average degree of saponification 98.5 mol%, degree of acetoacetyl group modification 5 mol%). An aqueous solution with a solid content concentration of 3.7% by weight was prepared, and 18 parts by weight of an aqueous solution containing a positively charged alumina colloid (average particle size 15 nm) with a solid content concentration of 10% by weight was added to 100 parts by weight of this aqueous solution. % to prepare a water-based adhesive.

(Production of absorption type polarizing member)
An acrylic film having a lactone ring structure with a thickness of 20 μm and a surface smoothness of 0.10 arcmin was bonded to one side of the absorption type polarizing film using the water-based adhesive (thickness after curing: 1 μm). On the other side, a 25 μm thick TAC film (manufactured by Konica Minolta, “KC2UA”) was pasted using the above water-based adhesive (thickness 1 μm after curing) to form an absorptive polarizing member with a surface smoothness of 0.48 arcmin. I got it.

(Preparation of λ/4 member)
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 to obtain a stretched film with a thickness of 47 μm. The obtained stretched film had Re(550) of 143 nm, Re(450)/Re(550) of 0.86, and Nz coefficient of 1.12.

(Production of protective member)
The following hard coat layer forming material was applied to an acrylic film having a lactone ring structure (thickness: 40 μm, surface smoothness: 0.45 arcmin), heated at 90°C for 1 minute, and the coated layer after heating was coated with a high-pressure mercury lamp. The coating layer was cured by irradiating ultraviolet rays with a cumulative light intensity of 300 mJ/cm ² to produce an acrylic film (44 μm thick, surface smoothness on the hard coat layer side 0.4 arcmin) on which a 4 μm thick hard coat layer was formed.
Next, on the hard coat layer, apply the following coating solution A for forming an antireflection layer with a wire bar, heat the applied coating solution at 80 ° C. for 1 minute, and dry it to form a coating film. did. The dried coating film was cured by irradiating ultraviolet rays with a cumulative light intensity of 300 mJ/cm ² using a high-pressure mercury lamp to form an antireflection layer A with a thickness of 140 nm.
Next, on the antireflection layer A, the following coating solution B for forming an antireflection layer is applied using a wire bar, and the applied coating solution is heated at 80° C. for 1 minute and dried to form a coating film. Formed. The dried coating film was cured by irradiating ultraviolet rays with a cumulative light intensity of 300 mJ/cm ² using a high-pressure mercury lamp to form an antireflection layer B having a thickness of 105 nm.
In this way, a protective member (thickness: 44 μm, surface smoothness on the antireflection layer side: 0.4 arcmin) was obtained.

(Hard coat layer forming material)
50 parts of urethane acrylic oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., "NK Oligo UA-53H"), polyfunctional acrylate whose main component is pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300") 30 parts, 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 20 parts, a leveling agent (manufactured by DIC Corporation, "GRANDIC PC4100") 1 part, and a photopolymerization initiator (manufactured by Ciba Japan, "Irgacure 907") Three parts were mixed and diluted with methyl isobutyl ketone to a solid content concentration of 50% to prepare a hard coat layer forming material.

(Coating liquid A for forming antireflection layer)
100 parts by weight of polyfunctional acrylate (manufactured by Arakawa Chemical Co., Ltd., trade name "Opstar KZ6728", solid content 20% by weight), 3 parts by weight of a leveling agent (manufactured by DIC Corporation, "GRANDIC PC4100"), and a photopolymerization initiator ( 3 parts by weight of "OMNIRAD907" (trade name, manufactured by BASF, solid content: 100% by weight) were mixed. The mixture was made to have a solid content of 12% by weight using butyl acetate as a diluting solvent, and stirred to prepare a coating liquid A for forming an antireflection layer.

(Coating liquid B 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 liquid B for forming an antireflection layer was prepared by stirring the mixture so that the amount was 4% by weight.

(Formation of adhesive layer A)
92 parts by weight of butyl acrylate, 2.9 parts by weight of acrylic acid, 0.1 part by weight of 2-hydroxyethyl acrylate, and N-acryloyl were placed in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. A monomer mixture containing 5 parts by weight of morpholine was charged. Furthermore, to 100 parts by weight of this monomer mixture, 0.1 part by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 200 parts by weight of ethyl acetate, and nitrogen gas was introduced while stirring gently. After purging the inside of the flask with nitrogen, a polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55° C. to prepare a solution of an acrylic polymer having a weight average molecular weight (Mw) of 1.78 million.
The resulting acrylic polymer solution was applied to a base film and dried to form an adhesive layer.

(Formation of adhesive layer B)
A monomer containing 94.9 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, and 0.1 parts by weight of 2-hydroxyethyl acrylate was placed in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. Brew the mixture. Further, to 100 parts by weight of this monomer mixture, 0.3 parts by weight of dibenzoyl peroxide as a polymerization initiator was charged together with ethyl acetate, and nitrogen gas was introduced while stirring gently to replace the inside of the flask with nitrogen. The polymerization reaction was carried out for 7 hours while maintaining the liquid temperature in the flask at 60°C. Next, ethyl acetate was added to the obtained reaction solution to adjust the solid content concentration to 30% by weight, thereby preparing a solution of an acrylic polymer having a weight average molecular weight (Mw) of 2.2 million.
To 100 parts by weight of the solid content of the obtained acrylic polymer solution, 0.6 parts by weight of trimethylolpropane/tolylene diisocyanate adduct (trade name: Coronate L, manufactured by Tosoh Corporation) and a silane coupling agent (product name: Coronate L, manufactured by Tosoh Corporation) were added. An acrylic pressure-sensitive adhesive was prepared by blending 0.075 parts by weight of KBM403 (manufactured by Shin-Etsu Chemical Co., Ltd.).
The obtained acrylic adhesive composition was applied to a base film and dried to form an adhesive layer.

(Preparation of optical laminate)
A reflective polarizing film ("APCFU4" manufactured by Nitto Denko Corporation) was bonded to the absorption type polarizing member with an adhesive layer A having a thickness of 5 μm interposed therebetween. Here, they were bonded together so that the reflection axis of the reflective polarizing film and the absorption axis of the absorbing polarizing film of the absorbing polarizing member were arranged parallel to each other.
Next, the protective member (an acrylic film on which a hard coat layer and an antireflection layer were formed) was bonded to the reflective polarizing film via an adhesive layer A having a thickness of 5 μm. Here, the acrylic film of the protective member was attached to the reflective polarizing film side.
Next, the above λ/4 member was attached to the absorption type polarizing member through an adhesive layer A having a thickness of 5 μm, so that the absorption axis of the absorption type polarizing film and the slow axis of the λ/4 member made an angle of 45°. I pasted it like this.
Next, a 15 μm thick adhesive layer B was attached to the λ/4 member to obtain an optical laminate.

[Example 2]
An optical laminate was obtained in the same manner as in Example 1, except that the protective member and the reflective polarizing film were laminated via the adhesive layer B having a thickness of 12 μm.

[Comparative example 1]
In the production of the protective member, a TAC film (thickness 60 μm, surface smoothness 0.5 arcmin) was used instead of the acrylic film having a lactone ring structure, and the hard coat layer was 12 μm thick and 72 μm thick. An optical laminate was obtained in the same manner as in Example 1, except that a protective member with a surface smoothness of 0.5 arcmin on the antireflection layer side was obtained.

[Comparative example 2]
In the production of the protective member, a TAC film (thickness 60 μm, surface smoothness 0.5 arcmin) was used instead of the acrylic film having a lactone ring structure, and the hard coat layer was 12 μm thick and 72 μm thick. An optical laminate was obtained in the same manner as in Example 2, except that a protective member with a surface smoothness of 0.5 arcmin on the antireflection layer side was obtained.

The optical laminates obtained in Examples and Comparative Examples were evaluated as follows. The evaluation results are shown in Table 1.
(1) Smoothness of the laminate The smoothness of the laminate was measured using a phase shift laser interferometer (manufactured by Zygo, product name "DynaFiz"). Specifically, the optical laminate was laminated onto a microslide glass (manufactured by Matsunami Glass Industry Co., Ltd., product name "S200200") to prevent foreign matter, air bubbles, and deformation lines from entering. Next, in order to remove the influence of minute air bubbles, defoaming was performed using a pressurized defoaming device (autoclave). The defoaming conditions were 50° C., 0.5 MPa, and 30 minutes. After defoaming, it was left to cool at room temperature for 30 minutes or more to obtain a measurement sample.
The measurement sample is placed on a measuring table with a vibration-isolating table, and a laser with a single wavelength (wavelength 633 nm) is used to interfere with a reference device whose flatness is guaranteed, and the relative displacement within a predetermined area (a circle of 30 mmφ) is measured. It was measured. For analysis, the value (equivalent to 2σ) obtained by doubling the angle index "Slope magnitude RMS" obtained by extracting frequency values from 0.1/mm to 1/mm is calculated as the laminate smoothness (unit: arcmin).
(2) Thickness variation (σ)
The thickness of the obtained optical laminate was measured at five arbitrary points within the plane using a digital gauge (manufactured by PEACOCK, model number DG-205), and the standard deviation thereof was determined.
(3) Appearance The appearance of the optical laminate (light transmitted through the lens) is improved by using an optical lens (manufactured by Thorabs, product name "LA1145") and a point light source (manufactured by Hamamatsu Photonics, model number "L8425-01"). was evaluated.
Specifically, an optical laminate cut into a 45 mm diameter circle was laminated on the flat side of the optical lens to prevent foreign matter, air bubbles, and deformation lines from entering the surface. Next, in order to remove the influence of minute air bubbles, defoaming was performed using a pressurized defoaming device (autoclave). The defoaming conditions were 50° C., 0.5 MPa, and 30 minutes. After defoaming, it was left to cool at room temperature for 30 minutes or more to obtain a measurement sample.
A point light source, an optical lens (measurement sample), and a screen were installed in this order, and the light from the point light source was projected onto the screen via the optical lens to evaluate its appearance. Here, the lens was held by a holder at a position where light from a point light source was incident from the flat side of the optical lens. The distance from the point light source to the screen was 1050 mm, and the distance from the optical lens to the screen was 130 mm.
The appearance was evaluated by 10 evaluators who visually observed the light reflected on the screen through an optical lens and judged the presence or absence of wrinkles and undulations. Table 1 shows the number of evaluators who judged that there were no wrinkles or undulations.

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 according to the embodiment of the present invention can be used, for example, in a display body such as VR goggles.

2 Display system, 4 Lens section, 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, 28 Absorption type polarizing member, 30 third retardation member, 31 first protection member, 32 second protection member, 41 adhesive layer, 42 adhesive layer, 43 adhesive layer, 44 adhesive layer, 45 adhesive layer, 46 adhesive layer, 51 adhesive layer, 52 adhesive layer, 100 first laminated part, 200 second laminated part (optical laminate).

Claims (8)

1. A laminated film having a base material and a surface treatment layer, a reflective polarizing member, an absorbing polarizing member, and a retardation member in this order,
   The base material of the laminated film contains a (meth)acrylic resin,
   The smoothness of the laminate is 0.70 arcmin or less,
   Optical laminate.
2. The optical laminate according to claim 1, wherein the base material of the laminate film has a surface smoothness of 0.7 arcmin or less.
3. The optical laminate according to claim 1, wherein the laminate film has a surface smoothness of 0.5 arcmin or less.
4. The optical laminate according to claim 1, wherein the surface treatment layer of the laminate film has an antireflection function.
5. The optical laminate according to claim 1, wherein the base material of the laminate film has a transmittance of 20% or less at a wavelength of 400 nm.
6. The optical laminate according to claim 1, wherein the absorption type polarizing member includes a protective layer and an absorption type polarizing film.
7. A lens unit used in a display system that displays images to a user, the lens unit comprising:
   The optical laminate according to any one of claims 1 to 6, which reflects light that is emitted forward from a display surface of a display element that represents an image and has passed through a polarizing member and a first λ/4 member. ,
   a first lens portion disposed on an optical path between the display element and the optical laminate;
   Disposed between the display element and the first lens part, transmits the light emitted from the display element, and transmits the light reflected by the reflective polarizing member of the optical laminate to the reflective polarizing member. A half mirror that reflects toward the
   a second lens portion disposed in front of the optical laminate;
   a second λ/4 member disposed on the optical path between the half mirror and the optical laminate;
   A lens section comprising:
8. A step of passing the light representing the image emitted through the polarizing member and the first λ/4 member through the half mirror and the first lens part;
   passing the light that has passed through the half mirror and the first lens section through a second λ/4 member;
   a step of reflecting the light that has passed through the second λ/4 member toward the half mirror by the optical laminate according to any one of claims 1 to 6;
   a step of allowing light reflected by the reflective polarizing member and the half mirror of the optical laminate to be transmitted through the reflective polarizing member by the second λ/4 member;
   passing the light that has passed through the reflective polarizing member through a second lens section;
   A display method having.

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