WO2023176632A1

WO2023176632A1 - Optical laminate, lens, and display method

Info

Publication number: WO2023176632A1
Application number: PCT/JP2023/008817
Authority: WO
Inventors: 理小島; 周作後藤
Original assignee: 日東電工株式会社
Priority date: 2022-03-14
Filing date: 2023-03-08
Publication date: 2023-09-21
Also published as: TW202400411A

Abstract

Provided is an optical laminate with which it is possible to reduce the weight and improve the vision qualitz of VR goggles. A optical laminate (200) according to one embodiment of the present invention comprises, in the following order: a laminated film (32) which has a substrate and a surface treatment layer; a reflection-type polarisation member (14); and an absorption-type polarisation member (28) which contains an absorption-type polarisation film. The surface smoothness of the absorption-type polarisation member is 0.4 arcmin or less.

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, in this order, a laminate film having a base material and a surface treatment layer, a reflective polarizing member, and an absorbing polarizing member including an absorbing polarizing film, and The surface smoothness of the polarizing member is 0.4 arcmin or less.
2. In the optical laminate described in 1 above, the absorption type polarizing film may have a thickness of 7 μm or less.
3. In the optical laminate described in 1 or 2 above, the absorption type polarizing film may be disposed adjacent to the reflective polarizing member, and the thickness of the absorption type polarizing film may be 4 μm or less.
4. In the optical laminate described in 1 or 2 above, the absorption type polarizing film may be disposed adjacent to the reflective polarizing member, and the thickness of the absorption type polarizing film may be 6 μm or more.
5. In the optical laminate according to 1 or 2 above, the absorption type polarizing member may include a protective layer, and the absorption type polarizing film may have a thickness of less than 6 μm.
6. In the optical laminate according to any one of 1 to 5 above, the laminate film, the reflective polarizing member, and the absorbing polarizing member may be integrated using an adhesive layer, and the adhesive layer The thickness of the layer may be between 4 μm and 13 μm.
7. In the optical laminate according to any one of 1 to 6 above, the surface treatment layer of the laminate film may have an antireflection function.
8. The optical laminate according to any one of 1 to 7 above may include the laminate film, the reflective polarizing member, the absorbing polarizing member, and the retardation member in this order.
9. The optical laminate according to any one of items 1 to 8 above may have a laminate smoothness of 0.7 arcmin or less.
10. The optical laminate according to any one of 1 to 9 above may have a degree of polarization of 99.5% or more.
11. The optical laminate according to any one of items 1 to 10 above may have a haze of 0.5% or less.
12. 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 the optical laminate according to any one of 1 to 11 above, which 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.
13. 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 11 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 even 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, and still more preferably 0.5 arcmin or less. 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.

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 facing 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 and effects, smoothness, thickness, and constituent materials of the second protection member.

As shown in FIG. 2, the second laminated section 200 may further include 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. If the third retardation member 30 does not include any member other than the third λ/4 member, 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. When the protective layer 28b is provided, the protective layer 28b may be disposed on the reflective polarizing member 14 side with respect to the absorption type polarizing film 28a, as shown in FIG. It may be arranged on the second lens section 24 side.

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, 0.001% 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 includes an absorption type polarizing film. 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 99.8% or more.

The surface smoothness of the absorption type polarizing member is preferably 0.4 arcmin or less, more preferably 0.3 arcmin or less, and still more preferably 0.2 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. By satisfying the above surface smoothness in an absorption type polarizing member that tends to affect the smoothness of the entire optical laminate, an optical laminate with excellent smoothness can be obtained. Moreover, according to such an optical laminate, significantly excellent visibility can be realized in the above-mentioned display system. For example, it is possible to suppress a phenomenon called ghost where an image appears double. Further, for example, a clear image without distortion can be realized. Substantially, the surface smoothness of the absorption type polarizing member is, for example, 0.1 arcmin or more.

An absorption type polarizing film is typically composed of a film containing a dichroic substance such as iodine or an organic dye. The thickness of the absorption type polarizing film is, for example, 10 μm or less, preferably 9 μm or less, more preferably 8 μm or less, and still more preferably 7 μm or less. By using an absorption type polarizing film having such a thickness, the above-mentioned surface smoothness can be satisfactorily satisfied. On the other hand, the thickness of the absorption type polarizing film is, for example, 1 μm or more.

For example, the absorption type polarizing film may be composed of a liquid crystal compound. The thickness of the absorption type polarizing film made of a liquid crystal compound can be, for example, 4 μm or less, 3 μm or less, or 2 μm or less. By using an absorption type polarizing film made of a liquid crystal compound, extremely high surface smoothness can be achieved. Further, by using an absorption type polarizing film made of a liquid crystal compound, the durability described below can be satisfactorily satisfied without using a protective layer as shown in FIG.

A lyotropic liquid crystal polymer is preferably used as the liquid crystal compound. The liquid crystal compound is typically aligned in a predetermined direction in the absorption type polarizing film, and the alignment state is fixed. Specifically, the absorption type polarizing film may be an alignment solidified layer of a liquid crystal compound. The structure of the liquid crystal phase of the liquid crystal compound may be, for example, any of a nematic phase, a smectic phase, and a columnar phase.

The lyotropic liquid crystalline polymer has, for example, a structural unit containing a ring structure, a linking group, and a sulfo group and/or a sulfonic acid group. The ring structure is typically included in the main chain of the lyotropic liquid crystalline polymer. The number of ring structures included in each structural unit is, for example, 1 or more and 5 or less. A typical example of the ring structure is an aromatic ring. Examples of the ring structure include a benzene ring, an oxazole ring, a thiazole ring, an oxadiazole ring, a biphenyl ring, and fused rings thereof. Preferably, a benzene ring is used. A linking group, for example, connects two ring structures. Both ends of the linking group are, for example, directly bonded to the ring structure. Examples of the linking group include an sp ³ carbon-containing linking group and an amide bond. Preferably, sp ³ carbon-containing linking groups are used. Specific examples of sp ³ carbon-containing linking groups include alkylene groups and oxyalkylene groups. Preferably, an alkylene group having 1 to 8 carbon atoms is used, and more preferably a methylene group and an ethylene group are used.

The sulfo group and/or sulfonic acid group can impart water solubility and lyotropic liquid crystallinity to the lyotropic liquid crystalline polymer. Sulfo groups and/or sulfonic acid groups are, for example, directly bonded to the ring structure. The number of sulfo groups and/or sulfonic acid groups contained in each structural unit is, for example, 1 or more and 5 or less. The counter cation of the sulfonic acid group typically includes an alkali metal cation, preferably Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , and Cs ⁺ . By exchanging the counter cation of the sulfonic acid group with a cation having lower water solubility (so-called insolubilization treatment), an absorption polarizing film with excellent water resistance can be obtained. Typical examples of cations having lower water solubility than alkali metal cations include ammonium ions and polyvalent metal cations. As the ammonium ion, ammonium ions of organic nitrogen compounds having two or more nitrogen atoms in the molecule are typically used. The number of nitrogen atoms contained in the organic nitrogen compound is not particularly limited, but is preferably 2 to 5, more preferably 2 to 3, and even more preferably 2. Examples of polyvalent metal cations include alkaline earth metal cations (e.g., Ca ²⁺ , Mg ²⁺ , Sr ²⁺ , Ba ²⁺ ), transition metal cations (e.g., La ³⁺ , Fe ³⁺ , Cr ³⁺ , Mn ²⁺ , Cu ²⁺ ). , Ce ³⁺ ), and poor metal cations (eg, Al ³⁺ , Pb ²⁺ , Sn ²⁺ , Zn ²⁺ ).

Examples of the structural units of the lyotropic liquid crystalline polymer include structures shown in the following formulas (1) to (23). Here, formulas (1), (3) to (10) represent structural units having an alkylene group (linking group) and a benzene ring (ring structure). Formula (2) shows a structural unit having an amide bond (linking group) and a benzene ring (ring structure). Formulas (11) to (19) represent structural units having an alkylene group (linking group) and a condensed ring (ring structure). Formulas (20) to (23) represent structural units having an oxyalkylene group (linking group) and a benzene ring (ring structure). The following formulas (2) to (23) contain a sulfo group for convenience, but a sulfonic acid group may be used.

(In formula (1), X represents a hydrogen atom or a counter cation selected from ammonium ions, alkali metal cations, alkaline earth metal cations, transition metal cations, or poor metal cations.)

Among such structural units, structural units having an alkylene group (linking group) and a benzene ring (ring structure) (formulas (1), (3) to (10) above), amide bonds (linking group) and benzene A structural unit having a ring (ring structure) (formula (2) above) is preferably used, and a structural unit represented by formula (1) above is more preferably used. The lyotropic liquid crystalline polymer may have, for example, one constituent unit alone or a combination of a plurality of constituent units among the above constituent units. Preferably, the lyotropic liquid crystalline polymer is a homopolymer (homopolymer) having only one of the above structural units, more preferably a structural unit represented by the above formula (1) or (2). A homopolymer of the structural unit represented by the above formula (1) is more preferable.

In the lyotropic liquid crystalline polymer, the number of repeating structural units is, for example, 25 or more and 1000 or less. The lyotropic liquid crystalline polymer itself may be transparent and exhibit substantially no absorption dichroism. The single transmittance of the lyotropic liquid crystalline polymer is, for example, 85% or more and 100% or less.

In one embodiment, the absorption type polarizing film made of a liquid crystal compound may contain an organic dye capable of imparting absorption dichroism as a dichroic substance. Examples of such organic dyes include organic dyes represented by the following formulas (24) to (26).

(In formula (24), A represents a sulfo group or a sulfonic acid group. m represents 1 or more and 4 or less. B represents a chlorine atom. p represents 0 or more and 2 or less. m+p is 4 or less. When A is a sulfonic acid group, its countercation is Na ⁺ , K ⁺ , Cs ⁺ or NH ₄ ⁺ .)

(In formula (25), A represents a sulfo group or a sulfonic acid group. m represents 1 or more and 4 or less. B represents a hydroxyl group. p represents 0 or more and 4 or less. C represents a sulfonyl group. n represents 0 or more and 2 or less. R represents an oxygen atom. q represents 0 or more and 4 or less. m+p+q is 6 or less. When A is a sulfonic acid group, its counter cation is Na ⁺ , K ⁺ , Cs ⁺ , or NH ₄ ⁺ .)

(In formula (26), A represents a sulfo group or a sulfonic acid group. When A is a sulfonic acid group, its counter cation is Na ⁺ , K ⁺ , Cs ⁺ , or NH ₄ ⁺ .)

Examples of organic dyes include azo dyes, azoxy dyes, azomethine dyes, stilbene dyes, polymethine dyes, cationic dyes, and naphthalene dyes described in paragraphs [0035] to [0037] of Japanese Patent Publication No. 2004-528603. dyes, perylene dyes, anthrone dyes; stilbene dyes described in U.S. Pat. No. 5,007,942 or U.S. Pat. No. 5,340,504; European Patent No. 0 530 106, European Patent Application Publication Mention may be made of the azo and metallized dyes described in US Pat. No. 0,626,598 or US Pat. No. 5,318,856.

In addition, as organic dyes, for example, C.I. I. Direct Yellow 12, C. I. Direct Yellow 28, C. I. Direct Yellow 44, C. I. Direct Yellow 142, C. I. Direct Orange 6, C. I. Direct Orange 26, C. I. Direct Orange 39, C. I. Direct Orange 72, C. I. Direct Orange 107, C. I. Direct Red 2, C. I. Direct Red 31, C. I. Direct Red 79, C. I. Direct Red 81, C. I. Direct Red 240, C. I. Direct Red 247, C. I. Direct Violet 9, C. I. Direct Violet 48, C. I. Direct Violet 51, C. I. Direct Blue 1, C. I. Direct Blue 15, C. I. Direct Blue 71, C. I. Direct Blue 78, C. I. Direct Blue 98, C. I. Direct Blue 168, C. I. Direct Blue 202, C. I. Direct Brown 106, C. I. Direct Brown 223, C. I. Direct dyes such as Direct Green 85; C.I. I. Active Yellow 1, C. I. Active Red 1, C. I. Active Red 6, C. I. Active Red 14, C. I. Active Red 46, C. I. Active Violet 1, C. I. Active Blue 9, C. I. an active dye such as Active Blue 10; C.I. I. Acid Orange 63, C. I. Acid Red 85, C. I. Acid Red 144, C. I. Acid Red 152, C. I. Acid Brown 32, C. I. Acid Violet 50, C. I. Acid Blue 18, C. I. Acid Blue 44, C. I. Acid Blue 61, C. I. Acid Blue 102, C. I. Acidic dyes such as Acid Black 21; C.I. I. Basic Red 12, Basic Brown (C.I.33500), C.I. I. Examples include cationic dyes such as basic black.

Furthermore, examples of organic dyes include organic molecules described in US Patent Application Publication No. 2001/0029638. Specific examples include polymethine dyes (e.g. pseudoisocyanine, piacyanol), triarylmethane dyes (e.g. Basic Turquose, Acid Light Blue 3), diaminoxanthene dyes (e.g. sulforhodamine), acridine dyes (e.g. Basic Yellow). K), sulfonated acridine dyes (e.g. trans-quinacridone), water-soluble derivatives of anthraquinone dyes (e.g. Activite Light Blue KX), sulfonated vat dyes (e.g. flavanthrone, indanthrene yellow, vat・Yellow 4K, Bat Dark Green G, Bat Violet C, Indanthrone, Perylene Violet, Bat Scarlet 2G), Azo dyes (e.g. Benzopurpurin 4B, Direct Lightfast Yellow O), Water-soluble diazine dyes (e.g. Acid Dark Blue 3), sulfonated dioxazine dyes (e.g. Pigment Violet Dioxazine), soluble thiazine dyes (e.g. methylene blue), water-soluble phthalocyanine derivatives (e.g. copper octacarboxyphthalocyanine salt), Cromoglycanate disodium, perylenetetracarboxylic acid diimide red (PADR), PADR benzimidazole (i.e. purple), naphthalenetetracarboxylic acid (i.e. yellow, deep red-purple), phenanthro-9',10':2,3- Examples include quinoxaline and sulfo derivatives of benzimidazoles.

Such organic dyes may be used alone or in combination of two or more. In a preferred embodiment, organic dyes represented by formulas (24) to (26) above are used in combination.

For example, an absorption type polarizing film composed of a liquid crystal compound is produced by coating a base film with a liquid crystal polymer solution obtained by dissolving the above lyotropic liquid crystal polymer in an aqueous solvent and drying it to form a lyotropic liquid crystal layer. It can be obtained by dyeing the layer. After staining, excess staining solution can be removed.

Examples of the aqueous solvent include water and a mixed solvent of water and alcohol, and preferably water is used. The solid content concentration in the liquid crystal polymer solution is, for example, 5% by mass or more and 30% by mass or less, preferably 10% by mass or more and 20% by mass or less. During coating of the liquid crystal polymer solution, a primer layer (eg, containing polyethyleneimine) may be formed on the coated surface of the base film. The thickness of the primer layer is, for example, 10 nm or more and 50 nm or less. The liquid crystal polymer solution can be applied by a coating method that can impart shear stress. A wire bar is typically used for coating. A lyotropic liquid crystal layer can be formed by drying the coating film of the liquid crystal polymer solution. The drying temperature is, for example, 40°C or higher and 80°C or lower, preferably 50°C or higher and 70°C or lower. The drying time is, for example, 10 seconds or more and 10 minutes or less, preferably 5 minutes or less. The lyotropic liquid crystalline polymer can be oriented by shear stress during coating, and the lyotropic liquid crystal layer can develop a retardation having a slow axis in the coating direction.

The above dyeing can typically be performed by immersing the lyotropic liquid crystal layer in a dyeing solution containing a dichroic substance. The temperature of the dyeing solution during dyeing is, for example, 10°C or more and 50°C or less, preferably 20°C or more and 40°C or less. The immersion time (dying time) is, for example, 5 seconds or more and 300 seconds or less, preferably 30 seconds or more and 180 seconds or less.

When the dichroic substance is iodine, the staining solution preferably further contains an iodine compound, more preferably an iodine compound and a polyvalent metal salt. Examples of iodine compounds include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide. Can be mentioned. Preferably potassium iodide is used. The mass ratio of iodine to iodine compound (iodine:iodine compound) in the staining solution is, for example, 1:5 to 1:30, preferably 1:5 to 1:15. When the staining solution contains a polyvalent metal salt, water resistance can be imparted to the absorption type polarizing film. Examples of polyvalent metal salts include chlorides, sulfates, nitrates, phosphates, oxalates, and acetates. Examples of the countermetal of the polyvalent metal salt include alkali metals, alkaline earth metals, transition metals, and poor metals. Specifically, barium, aluminum, lead, chromium, strontium, cerium, lanthanum, samarium, Examples include yttrium, copper, and iron. Preferably, strontium chloride is used. The mass ratio of iodine to polyvalent metal salt (iodine: polyvalent metal salt) in the staining solution is, for example, 1:5 to 1:30, preferably 1:5 to 1:15.

When the dichroic substance is an organic dye, the solid content concentration of the organic dye in the dyeing solution is, for example, 0.1% by mass or more and 3.0% by mass or less, and preferably 1.0% by mass or more. Further, when the organic dyes represented by the above formulas (24) to (26) are used together, the mass ratio of formula (24):formula (25):formula (26) is, for example, 40 to 60:10 to 30. :10-30.

Also, for example, the absorption type polarizing film may be composed of a resin film. In this case, the absorption type polarizing film is preferably a polyvinyl alcohol (PVA) film containing iodine. In one embodiment, the thickness of the absorptive polarizing film made of a resin film is preferably 6 μm or more. With such a thickness, the durability described below can be satisfactorily satisfied even without using a protective layer as shown in FIG. In another embodiment, the thickness of the absorptive polarizing film made of a resin film is preferably less than 6 μm. Even with such a thickness, by using a protective layer as shown in FIG. 3, the durability described below can be satisfactorily satisfied.

As a method for manufacturing an absorption type polarizing film composed of a resin film, for example, a polyvinyl alcohol resin layer containing a polyvinyl alcohol resin (PVA resin) and a halide is formed on one side of a long thermoplastic resin base material. (PVA resin layer) to form a laminate, and the laminate is subjected to aerial auxiliary stretching treatment, dyeing treatment, underwater stretching treatment, and heating while conveying in the longitudinal direction, so that the laminate is stretched in the width direction. A method including performing a drying shrinkage treatment to cause shrinkage by 2% or more in this order may be mentioned. The thickness of the resulting absorptive polarizing film can be controlled, for example, by adjusting the stretching ratio in the underwater stretching process.

The PVA-based resin layer is preferably formed by applying a coating liquid containing a PVA-based resin and a halide to a thermoplastic resin base material and drying the coating liquid. The content of the halide in the PVA resin layer is preferably 5 parts by weight to 20 parts by weight based on 100 parts by weight of the PVA resin. The thickness of the PVA resin layer is preferably 3 μm to 40 μm, more preferably 3 μm to 20 μm.

Examples of methods for applying the coating liquid include roll coating, spin coating, wire bar coating, dip coating, die coating, curtain coating, spray coating, and knife coating (comma coating, etc.). It will be done. The coating and drying temperature of the coating liquid is preferably 50°C or higher.

From the viewpoint of improving the adhesion between the thermoplastic resin base material and the PVA resin layer, the thermoplastic resin base material may be subjected to surface treatment such as corona treatment or heat treatment before forming the PVA resin layer. An easily adhesive layer may be formed on the plastic resin base material.

The thickness of the thermoplastic resin base material is preferably 20 μm to 300 μm, more preferably 50 μm to 200 μm. If it is less than 20 μm, for example, it may be difficult to form a PVA-based resin layer. If it exceeds 300 μm, for example, it may take a long time for the thermoplastic resin base material to absorb water in the underwater stretching treatment described below, and an excessive load may be required for stretching.

The water absorption rate of the thermoplastic resin base material is preferably 0.2% or more, more preferably 0.3% or more. The thermoplastic resin base material can absorb water, and the water can act as a plasticizer to be plasticized. As a result, stretching stress can be significantly reduced and stretching can be performed at a high magnification. On the other hand, the water absorption rate of the thermoplastic resin base material is preferably 3.0% or less, more preferably 1.0% or less. By using such a thermoplastic resin base material, it is possible to prevent problems such as a significant decrease in the dimensional stability of the base material during production and deterioration of the appearance of the resulting absorption type polarizing film. Furthermore, it is possible to prevent the base material from breaking or the PVA resin layer from peeling off from the base material during underwater stretching. Note that the water absorption rate of the thermoplastic resin base material can be adjusted, for example, by introducing a modifying group into the constituent material. The water absorption rate is a value determined according to JIS K 7209.

The glass transition temperature (Tg) of the thermoplastic resin base material is preferably 120°C or lower. By using such a thermoplastic resin base material, it is possible to sufficiently ensure the stretchability of the laminate while suppressing crystallization of the PVA-based resin layer. Considering the plasticization of the thermoplastic resin base material with water and the good performance of stretching in water, Tg is more preferably 100°C or less, and even more preferably 90°C or less. On the other hand, the Tg of the thermoplastic resin base material is preferably 60°C or higher. By using such a thermoplastic resin base material, defects such as deformation of the base material (e.g., occurrence of unevenness, sagging, wrinkles, etc.) when applying and drying the above coating solution can be prevented, resulting in good quality. A laminate can be produced. Further, the PVA resin layer can be stretched at a suitable temperature (for example, about 60° C.). Note that the glass transition temperature of the thermoplastic resin base material can be adjusted by, for example, heating using a crystallizing material that introduces a modifying group into the constituent material. The glass transition temperature (Tg) is a value determined according to JIS K 7121.

Examples of thermoplastic resins include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, polyamide resins, polycarbonate resins, and copolymer resins thereof. Can be mentioned. Among these, norbornene resins and amorphous polyethylene terephthalate resins are preferably used.

In one embodiment, amorphous (uncrystallized) polyethylene terephthalate resin is preferably used. Among these, amorphous (hard to crystallize) polyethylene terephthalate resin is preferably used. Specific examples of the amorphous polyethylene terephthalate resin include copolymers further containing isophthalic acid and/or cyclohexane dicarboxylic acid as a dicarboxylic acid, and copolymers further containing cyclohexanedimethanol or diethylene glycol as a glycol.

In a preferred embodiment, the thermoplastic resin base material is composed of a polyethylene terephthalate resin having an isophthalic acid unit. Such a thermoplastic resin base material has extremely excellent stretchability and can suppress crystallization during stretching. This is thought to be due to the fact that the introduction of the isophthalic acid unit imparts a large bend to the main chain. Polyethylene terephthalate resin has a terephthalic acid unit and an ethylene glycol unit. The content of the isophthalic acid unit is preferably 0.1 mol% or more, more preferably 1.0 mol% or more, based on the total of all repeating units. This is because a thermoplastic resin base material with extremely excellent stretchability can be obtained. On the other hand, the content of isophthalic acid units is preferably 20 mol% or less, more preferably 10 mol% or less, based on the total of all repeating units. By setting the content to such a content ratio, the degree of crystallinity can be favorably increased in the drying shrinkage treatment described below.

The thermoplastic resin base material may be stretched by any appropriate method before forming the PVA-based resin layer. For example, it may be stretched in the lateral direction of a long thermoplastic resin base material. The lateral direction is preferably a direction substantially perpendicular to the stretching direction of the laminate, which will be described later. The stretching temperature of the thermoplastic resin base material is preferably Tg-10°C to Tg+50°C relative to the glass transition temperature (Tg). The stretching ratio of the thermoplastic resin base material is preferably 1.5 times to 3.0 times.

As mentioned above, the coating liquid may contain a PVA-based resin and a halide. The coating liquid may typically be a solution in which a PVA-based resin and a halide are dissolved in a solvent. Examples of the solvent include water, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, polyhydric alcohols such as trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. Among these, water is preferably used. The PVA resin concentration is preferably 3 to 20 parts by weight based on 100 parts by weight of the solvent. The content of the halide in the coating liquid is preferably 5 parts by weight to 20 parts by weight, more preferably 10 parts by weight to 15 parts by weight, based on 100 parts by weight of the PVA resin.

Examples of the PVA-based resin include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. Ethylene-vinyl alcohol copolymer can be obtained by saponifying ethylene-vinyl acetate copolymer. The degree of saponification of the PVA resin is, for example, 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. It is. The degree of saponification can be determined according to JIS K 6726-1994. The average degree of polymerization of the PVA resin is, for example, 1,000 to 10,000, preferably 1,200 to 4,500, and more preferably 1,500 to 4,300. The average degree of polymerization can be determined according to JIS K 6726-1994. Examples of the halides include iodides such as potassium iodide, sodium iodide, and lithium iodide, and sodium chloride. Among these, potassium iodide is preferably used.

Additives may be added to the coating liquid. Examples of additives include plasticizers and surfactants. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants.

By stretching the PVA resin layer, the orientation of the polyvinyl alcohol molecules in the PVA resin can be increased, but when the stretched PVA resin layer is immersed in a liquid containing water, the orientation of the polyvinyl alcohol molecules can be improved. may become disordered and the orientation may deteriorate. When a laminate of a thermoplastic resin and a PVA-based resin layer is stretched in boric acid water at a relatively high temperature in order to stabilize the stretching of the thermoplastic resin, there is a remarkable tendency for the orientation to decrease. On the other hand, by stretching the laminate of a PVA resin layer containing a halide and a thermoplastic resin base material in air at high temperature (auxiliary stretching) before stretching it in boric acid water, the laminate after the auxiliary stretching can be Crystallization of the PVA resin in the PVA resin layer of the body can be promoted. As a result, when the PVA-based resin layer is immersed in a liquid, disordered 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. This can improve the optical properties of an absorption polarizing film obtained through a process performed by immersing the laminate in a liquid, such as a dyeing process and an underwater stretching process.

In order to obtain high optical properties, a two-stage stretching method that combines aerial stretching (auxiliary stretching) and boric acid water stretching may be selected. By introducing auxiliary stretching, it is possible to stretch while suppressing the crystallization of the thermoplastic resin base material, which reduces stretchability due to excessive crystallization of the thermoplastic resin base material during subsequent stretching in boric acid water. The problem can be solved and the laminate can be stretched to a high magnification. In addition, when applying PVA-based resin on a thermoplastic resin base material, in order to suppress the influence of the glass transition temperature of the thermoplastic resin base material, for example, compared to when applying PVA-based resin on a metal drum, , it is necessary to lower the coating temperature. As a result, the crystallization of the PVA-based resin becomes relatively low, which may cause a problem that sufficient optical properties cannot be obtained. On the other hand, by introducing auxiliary stretching, it is possible to increase the crystallinity of PVA-based resin even when applying PVA-based resin onto thermoplastic resin, making it possible to achieve high optical properties. Become. At the same time, by increasing the orientation of the PVA resin in advance, it is possible to prevent problems such as a decrease in orientation and dissolution of the PVA resin when it is immersed in water during subsequent dyeing and stretching treatments. High optical properties can be achieved.

The stretching method for aerial auxiliary stretching may be fixed end stretching (for example, stretching using a tenter stretching machine) or free end stretching (for example, uniaxial stretching by passing the laminate between rolls with different circumferential speeds). good. From the viewpoint of obtaining high optical properties, free end stretching is preferably used.

The stretching ratio of the aerial auxiliary stretching is preferably 2.0 times to 3.5 times. Aerial assisted stretching may be performed in one step or in multiple steps. In the case of multi-stage stretching, the stretching ratio is the product of the stretching ratios of each stage. The stretching direction in the aerial auxiliary stretching is preferably substantially the same as the stretching direction in the underwater stretching.

The stretching temperature of the aerial auxiliary stretching is preferably at least the glass transition temperature (Tg) of the thermoplastic resin base material, more preferably at least Tg + 10°C of the thermoplastic resin base material, and even more preferably at the glass transition temperature (Tg) of the thermoplastic resin base material. Tg+15°C or higher. On the other hand, the upper limit of the stretching temperature is preferably 170°C. By stretching at such a temperature, it is possible to suppress the rapid progress of crystallization of the PVA-based resin, and to suppress defects caused by crystallization (for example, hindering the orientation of the PVA-based resin layer due to stretching). . The crystallization index of the PVA-based resin after in-air assisted stretching is preferably 1.3 to 1.8, more preferably 1.4 to 1.7. The crystallization index of the PVA-based resin can be measured by the ATR method using a Fourier transform infrared spectrophotometer. Specifically, measurements are performed using polarized light as measurement light, and the crystallization index is calculated according to the following formula using the intensities at 1141 cm ^-1 and 1440 cm ^-1 of the obtained spectrum.
Crystallization index = (I _C /I _R )
Here, I _C is the intensity of 1141 cm ⁻¹ measured with the measurement light incident thereon, and I _R is the intensity of 1440 cm ⁻¹ measured with the measurement light incident thereon.

After the aerial auxiliary stretching treatment and before the underwater stretching treatment or dyeing treatment, an insolubilization treatment may be performed. The insolubilization treatment is typically performed by immersing the PVA resin layer in an aqueous boric acid solution. The insolubilization treatment imparts water resistance to the PVA-based resin layer and prevents the PVA from deteriorating in orientation when immersed in water. The concentration of the aqueous boric acid solution for insolubilization treatment is preferably 1 part by weight to 4 parts by weight per 100 parts by weight of water. The liquid temperature of the insolubilizing bath (boric acid aqueous solution) is preferably 20°C to 50°C.

The above dyeing treatment is typically performed by dyeing the PVA-based resin layer with iodine. Specifically, this is carried out by adsorbing iodine to the PVA resin layer. As a method for adsorbing iodine, preferably a method is employed in which the PVA resin layer (laminate) is immersed in a dye solution (dye bath) containing iodine.

The staining solution is preferably an iodine aqueous solution. In this case, the amount of iodine blended is preferably 0.05 part by weight to 0.5 part by weight per 100 parts by weight of water. In order to increase the solubility of iodine in water, it is preferable to add iodide to the iodine aqueous solution. Examples of iodides include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide. can be mentioned. Among these, potassium iodide is preferably used. The amount of iodide to be blended is preferably 0.1 parts by weight to 10 parts by weight, more preferably 0.3 parts by weight to 5 parts by weight, based on 100 parts by weight of water. The temperature of the dyeing solution during dyeing is preferably 20° C. to 50° C. in order to suppress dissolution of the PVA resin. When the PVA resin layer is immersed in the dyeing liquid, the immersion time is preferably 5 seconds to 5 minutes, more preferably 30 seconds to 90 seconds, in order to ensure the transmittance of the PVA resin layer.

The dyeing conditions (concentration, liquid temperature, immersion time) can be set so that the single transmittance and degree of polarization of the resulting absorption polarizing film fall within the above-mentioned ranges. For example, the content ratio of iodine and potassium iodide in the iodine aqueous solution used as the staining solution is preferably 1:5 to 1:20, more preferably 1:5 to 1:10.

When dyeing is performed continuously after immersing the laminate in a treatment bath containing boric acid (for example, insolubilization treatment), the boric acid contained in the treatment bath may mix into the dyeing bath, causing the dyeing bath to deteriorate. The boric acid concentration may change over time, resulting in unstable staining. In order to suppress such destabilization of dyeability, the upper limit of the concentration of boric acid in the dyeing bath is adjusted to preferably 4 parts by weight, more preferably 2 parts by weight, per 100 parts by weight of water. be done. On the other hand, the lower limit of the concentration of boric acid in the dyeing bath is preferably 0.1 part by weight, more preferably 0.2 part by weight, and still more preferably 0.5 part by weight, based on 100 parts by weight of water. It is. In one embodiment, a dye bath pre-blended with boric acid is used. This can reduce the rate of change in boric acid concentration when boric acid in the treatment bath is mixed into the dyeing bath. The amount of boric acid added to the dyeing bath in advance (that is, the content of boric acid not derived from the treatment bath) is preferably 0.1 parts by weight to 2 parts by weight based on 100 parts by weight of water. , more preferably 0.5 parts by weight to 1.5 parts by weight.

After the dyeing treatment and before the underwater stretching treatment, a crosslinking treatment may be performed. The above crosslinking treatment is typically performed by immersing the PVA resin layer in a boric acid aqueous solution. The crosslinking treatment imparts water resistance to the PVA-based resin layer, and subsequent underwater stretching can prevent the PVA from deteriorating in orientation when immersed in high-temperature water. The concentration of the aqueous boric acid solution for crosslinking treatment is preferably 1 to 5 parts by weight per 100 parts by weight of water. Moreover, when crosslinking treatment is performed after the above-mentioned dyeing treatment, it is preferable to further include an iodide. By blending iodide, it is possible to suppress elution of iodine adsorbed to the PVA-based resin layer. The amount of iodide to be blended is preferably 1 to 5 parts by weight per 100 parts by weight of water. Specific examples of iodides are as described above. The temperature of the crosslinking bath (boric acid aqueous solution) is preferably 20°C to 50°C.

The underwater stretching treatment is performed by immersing the laminate in a stretching bath. According to the underwater stretching treatment, stretching can be performed at a temperature lower than the glass transition temperature (typically about 80° C.) of the thermoplastic resin base material or the PVA resin layer, and the PVA resin layer can be It can be stretched while suppressing the As a result, a polarizing film having excellent optical properties can be manufactured.

Any suitable method can be adopted as the method for stretching the laminate. Specifically, fixed-end stretching or free-end stretching (for example, a method in which the laminate is passed between rolls having different circumferential speeds and uniaxially stretched) may be used. Preferably, free end stretching is chosen. The laminate may be stretched in one step or in multiple steps. When performing multi-stage stretching, the stretching ratio of the laminate described below is the product of the stretching ratios of each stage.

The stretching in water is preferably performed by immersing the laminate in an aqueous boric acid solution (stretching in boric acid water). By using a boric acid aqueous solution as a stretching bath, it is possible to impart rigidity to the PVA-based resin layer to withstand tension applied during stretching, and water resistance that does not dissolve in water. Specifically, boric acid can generate a tetrahydroxyborate anion in an aqueous solution and crosslink with the PVA-based resin through hydrogen bonding. As a result, rigidity and water resistance can be imparted to the PVA-based resin layer, and it can be stretched well, making it possible to manufacture an absorption type polarizing film having excellent optical properties.

The aqueous boric acid solution is preferably obtained by dissolving boric acid and/or a borate salt in water, which is a solvent. The boric acid concentration is preferably 1 to 10 parts by weight, more preferably 2.5 to 7 parts by weight, even more preferably 3 to 6 parts by weight, based on 100 parts by weight of water. It is. By setting the boric acid concentration to 1 part by weight or more, dissolution of the PVA-based resin layer can be effectively suppressed, and an absorption type polarizing film with higher characteristics can be manufactured. In addition to boric acid or a borate salt, an aqueous solution obtained by dissolving a boron compound such as borax, glyoxal, glutaraldehyde, etc. in a solvent can also be used.

Preferably, iodide is added to the stretching bath (boric acid aqueous solution). By blending iodide, it is possible to suppress elution of iodine adsorbed to the PVA-based resin layer. Specific examples of iodides are as described above. The concentration of iodide is preferably 0.05 parts by weight to 15 parts by weight, more preferably 0.5 parts by weight to 8 parts by weight, based on 100 parts by weight of water.

The stretching temperature (the liquid temperature of the stretching bath) is preferably 40°C or higher, more preferably 60°C or higher. At such a temperature, the film can be stretched well. Specifically, as described above, the glass transition temperature (Tg) of the thermoplastic resin base material is preferably 60° C. or higher in relation to the formation of the PVA-based resin layer. In this case, if the stretching temperature is lower than 40° C., there is a possibility that the stretching cannot be performed satisfactorily even if the plasticization of the thermoplastic resin base material by water is taken into account. On the other hand, the stretching temperature (the liquid temperature of the stretching bath) is preferably 85°C or lower, more preferably 75°C or lower. As the temperature of the stretching bath becomes higher, the solubility of the PVA-based resin layer increases, and there is a possibility that excellent optical properties may not be obtained. The immersion time of the laminate in the stretching bath is preferably 15 seconds to 5 minutes.

In one embodiment, the stretching ratio by underwater stretching is preferably 1.0 times to 2.2 times, more preferably 1.1 times to 2.0 times, and even more preferably 1.1 times. 1.8 times, particularly preferably 1.2 times to 1.6 times. By setting the stretching ratio in water stretching within such a range, an absorption polarizing film that can achieve the durability described below can be obtained without combining a protective layer. Moreover, a polarizing film in which breakage along the absorption axis direction is suppressed can be obtained. The total stretching ratio of the laminate is preferably 3.0 to 4.5 times, more preferably 3.0 to 4.3 times, even more preferably 3. It is .0 times to 4.0 times.

In one embodiment, the stretching ratio by underwater stretching is preferably 1.5 times or more, more preferably 3.0 times or more. The total stretching ratio of the laminate is preferably 5.0 times or more, more preferably 5.5 times or more, relative to the original length of the laminate. By achieving such a high stretching ratio, an absorption type polarizing film with excellent optical properties can be manufactured. Such a high stretching ratio can be achieved by employing an underwater stretching method (boric acid underwater stretching).

The above drying shrinkage treatment may be performed by zone heating in which the entire zone is heated, or by heating a conveyance roll (using a so-called heating roll). Preferably, both are used. By drying using a heating roll, heating curl of the laminate can be efficiently suppressed, and an absorption type polarizing film with excellent appearance can be manufactured. Specifically, by drying the laminate along a heating roll, it is possible to efficiently promote crystallization of the thermoplastic resin base material and increase the degree of crystallinity, which is relatively low. Even at drying temperatures, the degree of crystallinity of the thermoplastic resin base material can be increased favorably. As a result, the thermoplastic resin base material has increased rigidity and is in a state where it can withstand shrinkage of the PVA resin layer due to drying, thereby suppressing curling. Furthermore, by using a heating roll, the laminate can be dried while maintaining it in a flat state, so that not only curling but also wrinkles can be suppressed. At this time, the optical properties of the laminate can be improved by shrinking the laminate in the width direction by drying shrinkage treatment. This is because the orientation of PVA and PVA/iodine complex can be effectively improved. The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment is preferably 1% to 10%, more preferably 2% to 8%, particularly preferably 4% to 6%. By using a heating roll, the laminate can be continuously contracted in the width direction while being conveyed, and high productivity can be achieved.

For example, the drying conditions can be controlled by adjusting the heating temperature of the transport roll (temperature of the heating roll), the number of heating rolls, the contact time with the heating roll, etc. The temperature of the heating roll is preferably 60°C to 120°C, more preferably 65°C to 100°C, even more preferably 70°C to 80°C. The degree of crystallinity of the thermoplastic resin can be increased favorably, curling can be favorably suppressed, and excellent strength can be imparted to the laminate. Note that the temperature of the heating roll can be measured with a contact thermometer. The number of conveyance rolls used is usually 2 to 40, preferably 4 to 30. The contact time (total contact time) between the laminate and the heating roll is preferably 1 second to 300 seconds, more preferably 1 to 20 seconds, and even more preferably 1 to 10 seconds.

The heating roll may be provided within a heating furnace (for example, an oven) or may be provided on a normal production line (at room temperature). Preferably, it is provided in a heating furnace equipped with air blowing means. By using both heating roll drying and hot air drying, a sharp temperature change between the heating rolls can be suppressed, and shrinkage in the width direction can be easily controlled. The temperature of hot air drying is preferably 30°C to 100°C. The hot air drying time is preferably 1 second to 300 seconds. The wind speed of the hot air is preferably about 10 m/s to 30 m/s. Note that the wind speed is the wind speed within the heating furnace, and can be measured with a mini-vane digital anemometer.

Preferably, a washing treatment is performed after the underwater stretching treatment and before the drying shrinkage treatment. The above-mentioned cleaning treatment is performed, for example, by immersing the PVA-based resin layer in an aqueous potassium iodide solution.

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. Among these, (meth)acrylic resins and cycloolefin resins are preferably used. By employing these resins, a protective layer with excellent smoothness can be formed by extrusion molding, and an absorption type polarizing member with excellent smoothness can be obtained. Furthermore, the protective layer made of a cycloolefin resin can have excellent durability in birefringence characteristics (for example, has little change over time).

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. Further, by using a water-based adhesive, the resulting absorption type polarizing member can have excellent smoothness and satisfy the above-mentioned surface smoothness. Note that as the adhesive, for example, a curable adhesive such as an ultraviolet curable adhesive may be used. The curable adhesive may undergo curing shrinkage during formation of the adhesive layer, and the curing shrinkage may affect the smoothness of the resulting absorptive polarizing member.

The water-based adhesive preferably contains a PVA-based resin. The average degree of polymerization of the PVA resin contained in the water-based adhesive is preferably about 100 to 5,000, more preferably 1,000 to 4,000 from the viewpoint of adhesive properties. The average degree of saponification is preferably about 85 mol% to 100 mol%, more preferably 90 mol% to 100 mol%, from the viewpoint of adhesive properties. It is preferable that the PVA-based resin contains an acetoacetyl group. This is because the adhesion between the absorption type polarizing film and the protective layer can be excellent. The acetoacetyl group-containing PVA resin can be obtained, for example, by reacting a PVA resin and diketene by any method. The degree of acetoacetyl group modification of the acetoacetyl group-containing PVA resin is, for example, 0.1 mol% or more, preferably 0.1 mol% to 40 mol%, more preferably 1 mol% to 20 mol%. The content is more preferably 2 mol% to 7 mol%. Note that the degree of acetoacetyl group modification can be measured by NMR.

The water-based adhesive may contain any suitable crosslinking agent. As the crosslinking agent, for example, a compound having a functional group (for example, a methylol group) that is reactive with the PVA-based resin can be used. Further, the water-based adhesive may contain a metal compound colloid. The metal compound colloid may be one in which metal compound fine particles are dispersed in a dispersion medium, and may be electrostatically stabilized due to mutual repulsion of like charges of the fine particles, and may have permanent stability. . The average particle diameter of the fine particles forming the metal compound colloid can be any appropriate value, for example, as long as it does not adversely affect the optical properties of the absorption type polarizing member. The average particle diameter of the fine particles forming the metal compound colloid is, for example, 1 nm to 100 nm, preferably 1 nm to 50 nm. According to such an average particle diameter, for example, the fine particles can be uniformly dispersed in the adhesive layer, and nicks can be suppressed while ensuring adhesiveness. Here, the term "knick" refers to a local unevenness defect that occurs at the interface between the absorbing polarizing film and the protective layer.

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 even more preferably 0.2 μm or less. With such a thickness, it is possible to obtain an absorption type polarizing member that can satisfactorily satisfy the above-mentioned surface 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-mentioned members is preferably 20 μm or less, may be 15 μm or less, or may be 13 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. On the other hand, the thickness of each adhesive layer used for laminating the above-mentioned members is preferably 3 μm or more, and may be 4 μm or more. For example, the second protective member (laminated film) 32, the reflective polarizing member 14, and the absorptive polarizing member 28, or the second protective member (laminated film) 32, the reflective polarizing member 14, and the absorbing polarizing member 28 The third retardation member 30 may be integrated with an adhesive layer having a thickness of 4 μm to 13 μm.

The laminate smoothness of the optical laminate 200 is preferably 0.7 arcmin or less, more preferably 0.6 arcmin or less, and still more preferably 0.5 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).

It is preferable that the optical laminate 200 has excellent durability. For example, the optical laminate 200 preferably has a laminate smoothness of 0.7 arcmin or less, more preferably 0.6 arcmin or less, and even more preferably is 0.5 arcmin or less.

The degree of polarization (P) of the optical laminate 200 is, for example, 99.5% to 99.99%, preferably 99.8% or more.

The haze of the optical laminate 200 is preferably 0.5% or less, more preferably 0.4% or less, may be 0.3% or less, or may be 0.2% or less. . When the optical laminate that can be combined with the lens satisfies such a haze value, excellent visibility can be achieved. For example, the ghosting described above may be reduced. The haze of the optical laminate 200 is, for example, 0.01% or more.

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 primer composition was prepared according to US Patent Application Publication No. 2020/0110209. The obtained primer composition was applied to a 25 μm thick TAC film (manufactured by Konica Minolta, “KC2UA”) using a wire bar, and the coated film was dried at 60° C. for 3 minutes to form a 30 nm thick primer layer. was formed.
Next, a lyotropic liquid crystalline polymer consisting of the structural unit of the above formula (1) was dissolved in water to a solid content concentration of 14% by mass. As a lyotropic liquid crystalline polymer, Birefringent Aromatic Polymer (Structure P1) was produced according to Example 17 of US Patent Application Publication No. 2020/0110209. The lyotropic liquid crystalline polymer had a sodium sulfonate base. The obtained liquid crystal polymer aqueous solution was applied onto the primer layer using a wire bar and dried at 60° C. for 3 minutes to form a 2 μm thick lyotropic liquid crystal layer. Since the molecules of this material are oriented due to shear stress during coating, a phase difference with a slow axis in the coating direction was observed.
Next, organic dyes represented by the above formulas (24) to (26) were prepared according to US Patent Application Publication No. 2020/0110209. Thereafter, the organic dyes shown in formulas (24) to (26) above are dissolved in water at a mass ratio of formula (24): formula (25): formula (26) = 18:7:8, and the solid content concentration is A 1.9% by mass staining solution was prepared.
Next, the lyotropic liquid crystal layer was immersed in the dyeing solution for 90 seconds to dye it, and then immersed in a 10% by mass SrCl ₂ aqueous solution for 3 seconds to perform an insolubilization treatment. Thereafter, the lyotropic liquid crystal layer was washed by immersing it in pure water for 3 seconds, and then the excess water was blown off with compressed air and air-dried.
In this way, an absorption type polarizing film having a thickness of 2 μm and a surface smoothness of 0.18 arcmin was formed on the TAC film.

(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.

(Preparation of optical laminate)
A reflective polarizing film (Nitto Denko's "APCF ”) were pasted together. Here, the acrylic film of the protective member was attached to the reflective polarizing film side.
Next, only the above-mentioned absorption polarizing film was attached to the reflective polarizing film as an absorbing polarizing member through an adhesive layer having a thickness of 11 μm and a surface smoothness of 0.30 arcmin, and the reflective axis of the reflective polarizing film and the absorption polarizing film were attached to the reflective polarizing film. The membranes were attached so that their absorption axes were parallel to each other. After bonding, the TAC film (including the primer layer) was peeled off from the absorption type polarizing film.
Next, the above λ/4 member was attached to the absorption type polarizing film through an adhesive layer having a thickness of 5 μm and a surface smoothness of 0.30 arcmin, so that the absorption axis of the absorption type polarizing film and the slow axis of the λ/4 member were aligned. They were attached so that they formed an angle of 45°.
Next, an adhesive layer having a thickness of 15 μm and a surface smoothness of 0.30 arcmin was formed on 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 a polarizing film produced as described below was used as the absorption type polarizing film.

(Preparation of absorption type polarizing film)
As the thermoplastic resin base material, a long, amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of about 75° C. was used. One side of the resin base material was subjected to corona treatment.
Iodine was added to 100 parts by weight of a PVA resin prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, product name "Gosenex Z410") in a ratio of 9:1. A PVA aqueous solution (coating liquid) was prepared by dissolving 13 parts by weight of potassium chloride in water.
The PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60° C. to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate.
The obtained laminate was uniaxially stretched free end to 2.4 times in the longitudinal direction (longitudinal direction) between rolls having different circumferential speeds in an oven at 130° C. (in-air auxiliary stretching treatment).
Next, the laminate was immersed for 30 seconds in an insolubilization bath (boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40° C. (insolubilization treatment).
Next, the final polarizing film was added to a dyeing bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 to 100 parts by weight of water) at a liquid temperature of 30°C. It was immersed for 60 seconds while adjusting the concentration so that the single transmittance (Ts) was 42.0% or more (staining treatment).
Next, it was immersed for 30 seconds in a crosslinking bath (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C. (Crosslinking treatment).
Thereafter, while immersing the laminate in a boric acid aqueous solution (boric acid concentration: 4% by weight, potassium iodide concentration: 5% by weight) at a liquid temperature of 62°C, the laminate was moved vertically (longitudinal direction) once between rolls having different circumferential speeds. Uniaxial stretching was performed to .46 times (total stretching ratio was 3.5 times) (underwater stretching treatment).
Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20° C. (cleaning treatment).
Thereafter, while drying in an oven maintained at 90°C, it was brought into contact with a SUS heating roll whose surface temperature was maintained at 75°C for about 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 2%.
In this way, a polarizing film (absorption type polarizing film) with a thickness of 6.7 μm and a surface smoothness of 0.24 arcmin was formed on the resin base material.

[Example 3]
An optical laminate was obtained in the same manner as in Example 1 except that a polarizing film produced as described below was used as the absorption type polarizing film.

(Preparation of absorption type polarizing film)
As the thermoplastic resin base material, a long, amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of about 75° C. was used. One side of the resin base material was subjected to corona treatment.
Iodine was added to 100 parts by weight of a PVA resin prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, product name "Gosenex Z410") in a ratio of 9:1. A PVA aqueous solution (coating liquid) was prepared by dissolving 13 parts by weight of potassium chloride in water.
The PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60° C. to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate.
The obtained laminate was uniaxially stretched free end to 2.4 times in the longitudinal direction (longitudinal direction) between rolls having different circumferential speeds in an oven at 130° C. (in-air auxiliary stretching treatment).
Next, the laminate was immersed for 30 seconds in an insolubilization bath (boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40° C. (insolubilization treatment).
Next, the final polarizing film was added to a dyeing bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 to 100 parts by weight of water) at a liquid temperature of 30°C. It was immersed for 60 seconds while adjusting the concentration so that the single transmittance (Ts) was 42.0% or more (staining treatment).
Next, it was immersed for 30 seconds in a crosslinking bath (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C. (Crosslinking treatment).
Thereafter, while immersing the laminate in a boric acid aqueous solution (boric acid concentration: 4% by weight, potassium iodide concentration: 5% by weight) at a liquid temperature of 62°C, the laminate was completely rolled in the longitudinal direction (longitudinal direction) between rolls having different circumferential speeds. Uniaxial stretching was performed so that the stretching ratio was 5.5 times (underwater stretching treatment).
Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20° C. (cleaning treatment).
Thereafter, while drying in an oven maintained at 90°C, it was brought into contact with a SUS heating roll whose surface temperature was maintained at 75°C for about 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%.
In this way, a polarizing film (absorption type polarizing film) having a thickness of 5 μm and a surface smoothness of 0.26 arcmin was formed on the resin base material.

[Example 4]
An optical laminate was obtained in the same manner as in Example 1, except that an absorption type polarization member produced as described below was used as the absorption type polarization member.

(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 added to an absorption type polarizing film prepared in the same manner as in Example 3 using the following water-based adhesive (thickness after curing: 0.1 μm). The films were bonded together to obtain an absorption type polarizing member.

(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.

[Comparative example 1]
An optical laminate was obtained in the same manner as in Example 1, except that an absorption type polarization member produced as described below was used as the absorption type polarization member.

(Production of absorption type polarizing member)
A lactone ring structure with a thickness of 20 μm and a surface smoothness of 0.10 arcmin was formed on the absorption polarizing film produced in the same manner as in Example 3 using the following ultraviolet curable adhesive (thickness after curing: 0.7 μm). An acrylic film containing the above was bonded together to obtain an absorption type polarizing member.

(Preparation of ultraviolet curable adhesive)
62 parts by weight of hydroxyethyl acrylamide (manufactured by Kojinsha, trade name "HEAA"), 25 parts by weight of acryloylmorpholine (manufactured by Kojinsha, trade name "ACMO"), and PEG400# diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., product 7 parts by weight of ``Light Acrylate 9EG-A''), 3 parts by weight of BASF's brand name ``Irgacure 907'', and 3 parts by weight of Nippon Kayaku Co., Ltd.'s brand name ``KAYACURE DETX-S''. A UV curable adhesive was prepared by mixing for a minute.

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) Durability After the measurement in (1) above, the measurement sample was placed in an oven at 80°C for 500 hours. Thereafter, the smoothness of the laminate was measured in the same manner as in (1) above, and the difference between the measured values before and after heating was calculated to evaluate durability.
(Evaluation criteria)
- Very good: The amount of change in the measured value is less than +0.05 arcmin - Good: The amount of change in the measured value is +0.05 arcmin or more and less than 0.10 arcmin (3) Good appearance Optical lens (manufactured by Thorabs, product name "LA1145") The appearance of the optical laminate (light transmitted through the lens) was evaluated using a point light source (manufactured by Hamamatsu Photonics, model number "L8425-01").
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 light reflected on the screen through the optical lens was visually observed, and the appearance was evaluated using the following evaluation criteria.
(Evaluation criteria)
・Good: Wrinkles and undulations are not visible. ・Bad: Wrinkles and undulations are visible. ”) was used to measure haze.
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 obtained measurement sample was subjected to the above measurement.

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 purpose.

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

A laminated film having a base material and a surface treatment layer, a reflective polarizing member, and an absorbing polarizing member including an absorbing polarizing film, in this order,
The surface smoothness of the absorptive polarizing member is 0.4 arcmin or less,
Optical laminate.
The optical laminate according to claim 1, wherein the absorption type polarizing film has a thickness of 7 μm or less.
The optical laminate according to claim 1, wherein the absorption type polarizing film is arranged adjacent to the reflective polarizing member, and the thickness of the absorption type polarizing film is 4 μm or less.
The optical laminate according to claim 1, wherein the absorption type polarizing film is arranged adjacent to the reflective polarizing member, and the thickness of the absorption type polarizing film is 6 μm or more.
The optical laminate according to claim 1, wherein the absorption type polarizing member includes a protective layer, and the thickness of the absorption type polarizing film is less than 6 μm.
The optical laminate according to claim 1, wherein the laminate film, the reflective polarizing member, and the absorbing polarizing member are integrated using an adhesive layer, and the adhesive layer has a thickness of 4 μm to 13 μm. body.
The optical laminate according to claim 1, wherein the surface treatment layer of the laminate film has an antireflection function.
The optical laminate according to claim 1, comprising the laminate film, the reflective polarizing member, the absorbing polarizing member, and the retardation member in this order.
The optical laminate according to claim 1, wherein the laminate smoothness is 0.7 arcmin or less.
The optical laminate according to claim 1, having a degree of polarization of 99.5% or more.
The optical laminate according to claim 1, having a haze of 0.5% or less.
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 11, 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:
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 11;
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.