JP2024007555A - Polarizing plate having retardation layer and picture display unit using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate having a retardation layer including an oriented solidified layer of a liquid crystal compound, in which a removal of the oriented solidified layer of the liquid crystal compound is restricted.

SOLUTION: A polarizing plate having a retardation layer includes: a polarizing plate including a polarizer and a protective layer at least on one side of the polarizer; and a retardation layer laminated on the polarizing plate interposing a first adhesive layer. The retardation layer is an oriented solidified layer of a liquid crystal compound, and includes a penetration layer formed by penetration of an adhesive agent of the first adhesive layer in a vicinity of a boundary face with the first adhesive layer.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a polarizing plate with a retardation layer and an image display device using the same.

In recent years, image display devices typified by liquid crystal display devices and electroluminescent (EL) display devices (eg, organic EL display devices and inorganic EL display devices) have rapidly become popular. Polarizing plates and retardation plates are typically used in image display devices. In practice, a polarizing plate with a retardation layer that integrates a polarizing plate and a retardation plate is widely used (for example, Patent Document 1), but recently there has been a strong demand for thinner image display devices. With this trend, there is an increasing demand for thinner polarizing plates with retardation layers. In order to meet such demands, a layer formed by aligning a liquid crystal compound in a predetermined direction and fixing the alignment state has been proposed as a retardation layer. However, there is a problem in that a layer formed of such a liquid crystal compound is easily peeled off.

Patent No. 5745686

The present invention has been made in order to solve the above-mentioned conventional problems, and its main purpose is to provide a retardation layer that has an alignment solidified layer of a liquid crystal compound, and in which peeling of the alignment solidified layer of the liquid crystal compound is suppressed. The purpose of the present invention is to provide a polarizing plate.

The polarizing plate with a retardation layer of the present invention includes a polarizing plate including a polarizer and a protective layer on at least one side of the polarizer; a retardation plate laminated on the polarizing plate via a first adhesive layer. It has a layer and; The retardation layer is an alignment solidified layer of a liquid crystal compound, and includes a permeation layer formed by permeation of the adhesive of the first adhesive layer near the interface with the first adhesive layer.
In one embodiment, the polarizing plate includes the polarizer and a protective layer disposed on a side of the polarizer opposite to the retardation layer.
In another embodiment, the polarizing plate includes the polarizer and protective layers disposed on both sides of the polarizer. In this case, the protective layer disposed on the retardation layer side of the polarizer is formed by penetration of the adhesive of the first adhesive layer into the vicinity of the interface with the first adhesive layer. It may contain layers.
In one embodiment, the retardation layer is a single layer of an alignment solidified layer of a liquid crystal compound, the Re(550) of the retardation layer is 100 nm to 190 nm, and the slow axis of the retardation layer and the above The angle formed with the absorption axis of the polarizer is 40° to 50°.
In another embodiment, the retardation layer includes a first liquid crystal compound alignment solidified layer and a second liquid crystal compound alignment solidified layer laminated on the first liquid crystal compound alignment solidified layer via a second adhesive layer. a solidified alignment layer of a liquid crystal compound; the first solidified liquid crystal compound alignment layer and the second solidified liquid crystal compound alignment layer each have a second solidified liquid crystal compound layer near the interface with the second adhesive layer; The adhesive layer includes a permeable layer formed by permeation of the adhesive of the adhesive layer. The Re(550) of the alignment solidified layer of the first liquid crystal compound is 200 nm to 300 nm, and the angle between its slow axis and the absorption axis of the polarizer is 10° to 20°; Re(550) of the alignment solidified layer of the liquid crystal compound is 100 nm to 190 nm, and the angle between its slow axis and the absorption axis of the polarizer is 70° to 80°.
In one embodiment, the adhesives of the first and second adhesive layers each include acryloylmorpholine.
In one embodiment, the polarizing plate with a retardation layer further includes another retardation layer outside the retardation layer, and the retardation index characteristic of the another retardation layer satisfies nz>nx=ny. Show relationships.
According to another aspect of the present invention, an image display device is provided. This image display device includes the above polarizing plate with a retardation layer.

According to the present invention, in a polarizing plate with a retardation layer having an alignment fixed layer of a liquid crystal compound, the adhesive of the adhesive layer penetrates into the vicinity of the interface between the alignment fixed layer of the liquid crystal compound and an adjacent adhesive layer. By providing the permeation layer formed by the above method, it is possible to realize a polarizing plate with a retardation layer in which peeling of the alignment solidified layer of the liquid crystal compound is suppressed.

1 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to yet another embodiment of the present invention. 2 is a transmission electron microscope (TEM) image showing the state of the interface between the adhesive layer and the retardation layer in the polarizing plate with a retardation layer of Example 1. 3 is a TEM image showing the state of the interface between the adhesive layer and the retardation layer in the polarizing plate with a retardation layer of Comparative Example 1.

Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

(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°.
(6) Orientation fixed layer "Orientation fixed layer" refers to a layer in which a liquid crystal compound is oriented in a predetermined direction and the orientation state is fixed. The term "alignment hardened layer" is a concept that includes an orientation hardened layer obtained by curing a liquid crystal monomer as described below.
(7) (meth)acrylic “(meth)acrylic” refers to acrylic and/or methacrylic.

A. Overall Configuration of Polarizing Plate with Retardation Layer FIG. 1 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention. The illustrated polarizing plate with a retardation layer 100 includes a polarizing plate 10 and a retardation layer 20 laminated on the polarizing plate 10 via a first adhesive layer 31. A polarizing plate typically includes a polarizer and a protective layer disposed on at least one side of the polarizer. The illustrated polarizing plate 10 includes a polarizer 11 and a first protective layer 12 disposed on one side of the polarizer 11 (on the opposite side to the retardation layer). In the embodiment of the present invention, the retardation layer 20 is an alignment solidified layer of a liquid crystal compound, and is formed by penetrating the adhesive of the first adhesive layer 31 into the vicinity of the interface with the first adhesive layer 31. It includes a permeable layer 20a. By providing such a permeation layer, peeling of the retardation layer (orientation solidified layer of liquid crystal compound) can be significantly suppressed. Furthermore, by directly providing the first adhesive layer 31 on the polarizer 11 as in this embodiment, peeling of the retardation layer (orientation solidified layer of liquid crystal compound) can be particularly significantly suppressed. According to the configuration of this embodiment, for example, the peel strength between the first adhesive layer and the alignment solidified layer of the liquid crystal compound becomes extremely high, and in a normal peeling operation, the alignment of the first adhesive layer and the liquid crystal compound It does not peel off from the solidified layer, and can also prevent other interlayer peeling (for example, peeling between the polarizer and the first adhesive layer).

FIG. 2 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. In the illustrated polarizing plate 101 with a retardation layer, the polarizing plate 10 includes a polarizer 11, a first protective layer 12 disposed on one side of the polarizer 11 (on the opposite side to the retardation layer), and a second protective layer 13 disposed on the other side (on the retardation layer side) of the polarizer 11. In this embodiment, the second protective layer 13 includes a permeable layer 13a formed by permeation of the adhesive of the first adhesive layer 31 near the interface with the first adhesive layer 31. Good too. By providing the permeation layer 13a, for example, it is possible to prevent peeling between the first adhesive layer and the alignment solidified layer of the liquid crystal compound, and to increase the peel strength between the first adhesive layer and the second protective layer. can do. Note that the permeable layer 13a is optional and may or may not be formed on the second protective layer 13.

The retardation layer 20 is an alignment solidified layer of a liquid crystal compound as described above. The retardation layer 20 may be a single layer of alignment fixed layers as shown in FIGS. 1 and 2, or may be a lamination of a first alignment fixed layer 21 and a second alignment fixed layer 22 as shown in FIG. It may have a structure. In the embodiment shown in FIG. 3, the first oriented solidified layer 21 and the second oriented solidified layer 22 are laminated with the second adhesive layer 32 in between. In this case, the first oriented solidified layer 21 includes a permeation layer 21a formed by permeation of the adhesive of the second adhesive layer 32 near the interface with the second adhesive layer 32; The alignment solidified layer 22 includes a permeation layer 22a formed by permeation of the adhesive of the second adhesive layer 32 near the interface with the second adhesive layer 32. In this embodiment, peeling between the second adhesive layer and the first and second alignment fixed layers 21 and 22 can be particularly significantly suppressed. For example, in a normal peeling operation, the second adhesive layer is not peeled off from the first oriented solidified layer 21 and the second oriented solidified layer 22, and cohesive failure of the second adhesive layer may occur. In the embodiment of the present invention, the permeation layer 20a (in this embodiment) is formed by the adhesive of the first adhesive layer 31 penetrating into the vicinity of the interface between the retardation layer 20 and the first adhesive layer 31. In terms of the configuration, it is sufficient that 21a) is formed. Therefore, the first oriented solidified layer 21 and the second oriented solidified layer 22 may be laminated, for example, with an adhesive layer interposed therebetween.

As described above, the permeable layer is formed by permeation of the adhesive of the adhesive layer. Specifically, the permeable layers 20a, 21a and 22a are the portions of the liquid crystal compound alignment and solidified layers 20, 21 and 22 where the adhesive component is present; the permeable layer 13a is the portion of the second protective layer 13 This is the part where the adhesive component is present. Although the detailed structure of the permeation layer is not clear, it is a combination of the permeated adhesive molecules (substantially the curing component before curing) and the liquid crystal molecules of the alignment solidified layer or the resin molecules constituting the second protective layer. It is presumed that entanglements (in some cases, chemical bonds due to reactions) are formed, thereby suppressing peeling. Furthermore, by forming the permeation layer, interface reflection can be suppressed, and as a result, display unevenness can be suppressed.

The thickness of the permeation layer is preferably 5 nm to 100 nm, more preferably 10 nm to 50 nm. The ratio of the thickness of the permeation layer to the thickness of the orientation solidified layer of the liquid crystal compound (permeation layer/orientation solidification layer) is preferably 0.2% to 20%, more preferably 0.2% to 10%. When the thickness and thickness ratio of the permeable layer are within such ranges, peeling can be satisfactorily suppressed and display unevenness can be satisfactorily suppressed. If the thickness of the permeable layer becomes too large, the permeable layer and/or the adhesive layer may become brittle and may peel off more easily. Note that the thickness of the permeation layer can be measured from a transmission electron microscope (TEM) image of a cross section of the polarizing plate with a retardation layer.

The peel strength between the first adhesive layer 31 and the alignment solidified layer 20 of the liquid crystal compound is preferably 0.7 N/15 mm or more, more preferably 1.0 N/15 mm or more, and even more preferably 1.5 N. /15mm or more. The upper limit of the peel strength is difficult to specify. Before the first adhesive layer 31 and the alignment solidified layer 20 of the liquid crystal compound peel off, the first adhesive layer may undergo cohesive failure or the first adhesive layer and the polarizing plate (typically, the second This is because delamination occurs between the protective layer and the protective layer. The same applies to the peel strength between the second adhesive layer 32 and the first and second alignment fixed layers 21 and 22. Note that the peel strength can be measured, for example, at a peel angle of 90° and a peel rate of 300 mm/min.

The above embodiments may be combined as appropriate, and the components in the above embodiments may be modified in a manner obvious to those skilled in the art. For example, the polarizing plate of the polarizing plate with a retardation layer shown in FIG. 3 may be provided with a second protective layer as shown in FIG. The retardation layer of the polarizing plate with a retardation layer shown in FIGS. As long as it is an alignment solidified layer of a liquid crystal compound, it may be replaced with an optically equivalent structure.

The polarizing plate with a retardation layer according to the embodiment of the present invention may further include other optical functional layers. For example, the polarizing plate with a retardation layer may further include another retardation layer and/or a conductive layer or an isotropic substrate with a conductive layer (none of which are shown). Another retardation layer and a conductive layer or an isotropic substrate with a conductive layer are typically provided outside the retardation layer 20 (on the opposite side to the polarizing plate 10). Another retardation layer typically exhibits a refractive index characteristic of nz>nx=ny. Such another retardation layer may be provided, for example, when the retardation layer 20 is a single layer of alignment fixed layer. Another retardation layer and a conductive layer or an isotropic substrate with a conductive layer are typically provided in this order from the retardation layer 20 side. Another retardation layer, a conductive layer, or an isotropic substrate with a conductive layer are typically arbitrary layers provided as needed, and either or both may be omitted. Note that when a conductive layer or an isotropic substrate with a conductive layer is provided, the polarizing plate with a retardation layer is a so-called inner polarizing plate in which a touch sensor is incorporated between an image display cell (for example, an organic EL cell) and a polarizing plate. It can be applied to a touch panel type input display device. The type, characteristics, number, combination, arrangement position, etc. of the optical functional layers that can be provided in the polarizing plate with a retardation layer can be appropriately set depending on the purpose.

The polarizing plate with a retardation layer of the present invention may have a single leaf shape or may have an elongated shape. In this specification, "elongated shape" means an elongated shape whose length is sufficiently longer than its width; for example, an elongated shape whose length is at least 10 times, preferably at least 20 times its width. include. The elongated polarizing plate with a retardation layer can typically be wound into a roll.

Practically, an adhesive layer (not shown) is provided as the outermost layer on the opposite side of the retardation layer to the polarizing plate, and the polarizing plate with the retardation layer can be attached to the image display cell. Furthermore, it is preferable that a release film is temporarily attached to the surface of the adhesive layer until the polarizing plate with a retardation layer is used. Temporarily attaching a release film protects the adhesive layer and enables roll formation of a polarizing plate with a retardation layer.

The total thickness of the polarizing plate with a retardation layer is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, particularly preferably 55 μm or less. The lower limit of the total thickness may be, for example, 28 μm. According to the embodiments of the present invention, it is possible to realize such an extremely thin polarizing plate with a retardation layer. Such a polarizing plate with a retardation layer can have extremely excellent flexibility and bending durability. Such a polarizing plate with a retardation layer can be particularly suitably applied to a curved image display device and/or a bendable or bendable image display device. Note that the total thickness of the polarizing plate with a retardation layer refers to the total thickness of all layers constituting the polarizing plate with a retardation layer, excluding the adhesive layer.

Hereinafter, the constituent elements of the polarizing plate with a retardation layer will be explained in more detail.

B. Polarizing plate B-1. Polarizer As the polarizer 11, any suitable polarizer may be adopted. For example, the resin film forming the polarizer may be a single layer resin film or a laminate of two or more layers.

Specific examples of polarizers composed of single-layer resin films include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene/vinyl acetate copolymer films. Examples include those that have been dyed with dichroic substances such as iodine and dichroic dyes and stretched, and polyene-based oriented films such as dehydrated PVA and dehydrochloric acid treated polyvinyl chloride. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because it has excellent optical properties.

The above-mentioned staining with iodine is performed, for example, by immersing the PVA-based film in an iodine aqueous solution. The stretching ratio of the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing process or may be performed while dyeing. Alternatively, it may be dyed after being stretched. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc. For example, by immersing a PVA film in water and washing it with water before dyeing, you can not only wash dirt and anti-blocking agents from the surface of the PVA film, but also swell the PVA film and prevent uneven dyeing. It can be prevented.

Specific examples of polarizers obtained using a laminate include a laminate of a resin base material and a PVA resin layer (PVA resin film) laminated on the resin base material, or a laminate of a resin base material and the resin Examples include polarizers obtained using a laminate with a PVA-based resin layer coated on a base material. A polarizer obtained using a laminate of a resin base material and a PVA-based resin layer coated on the resin base material can be obtained by, for example, applying a PVA-based resin solution to the resin base material and drying it. Forming a PVA-based resin layer thereon to obtain a laminate of a resin base material and the PVA-based resin layer; stretching and dyeing the laminate to use the PVA-based resin layer as a polarizer; obtain. In this embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, the stretching may further include stretching the laminate in air at a high temperature (for example, 95° C. or higher) before stretching in the boric acid aqueous solution, if necessary. The obtained resin base material/polarizer laminate may be used as is (that is, the resin base material may be used as a protective layer for the polarizer), or the resin base material may be peeled from the resin base material/polarizer laminate. However, any appropriate protective layer may be laminated on the peeled surface depending on the purpose. Details of the method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Publication No. 2012-73580. The entire description of this publication is incorporated herein by reference.

The thickness of the polarizer is preferably 15 μm or less, more preferably 1 μm to 12 μm, even more preferably 3 μm to 12 μm, particularly preferably 3 μm to 8 μm. When the thickness of the polarizer is within such a range, curling during heating can be suppressed well, and good appearance durability during heating can be obtained.

The polarizer preferably exhibits absorption dichroism at a wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is 43.0% to 46.0%, preferably 44.5% to 46.0%, as described above. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more.

B-2. Protective Layer The first protective layer 12 and the second protective layer 13 are each formed of any suitable film that can be used as a protective layer of a polarizer. Specific examples of materials that are the main components of the film include cellulose resins such as triacetylcellulose (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, and polysulfones. Examples include transparent resins such as polystyrene, polynorbornene, polyolefin, (meth)acrylic, and acetate. Further, thermosetting resins or ultraviolet curable resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone resins may also be mentioned. Other examples include glassy polymers such as siloxane polymers. Furthermore, the polymer film described in JP-A-2001-343529 (WO01/37007) can also be used. Materials for this film include, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in its side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in its side chain. For example, a resin composition containing an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile/styrene copolymer can be used. The polymer film may be, for example, an extrusion molded product of the resin composition.

The polarizing plate with a retardation layer according to an embodiment of the present invention is typically placed on the viewing side of an image display device, as described later, and the first protective layer 12 is typically placed on the viewing side. Ru. Therefore, the first protective layer 12 may be subjected to surface treatments such as hard coat treatment, antireflection treatment, antisticking treatment, and antiglare treatment, as necessary. Furthermore/or, the first protective layer 12 may be treated, if necessary, to improve visibility when viewed through polarized sunglasses (typically, an (elliptical) circularly polarizing function is applied); (imparting an ultra-high phase difference) may also be applied. By performing such processing, excellent visibility can be achieved even when the display screen is viewed through polarized lenses such as polarized sunglasses. Therefore, the polarizing plate with a retardation layer can be suitably applied to an image display device that can be used outdoors.

The thickness of the first protective layer is typically 300 μm or less, preferably 100 μm or less, more preferably 5 μm to 80 μm, and still more preferably 10 μm to 60 μm. In addition, when surface treatment is performed, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

In one embodiment, the second protective layer 13 is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is -10 nm to +10 nm. say. The second protective layer 13 may be a retardation layer having any suitable retardation value in one embodiment. In this case, the in-plane retardation Re (550) of the retardation layer is, for example, 110 nm to 150 nm. The thickness of the second protective layer is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm, even more preferably 10 μm to 60 μm.

C. Retardation Layer As described above, the retardation layer 20 is an alignment solidified layer of a liquid crystal compound. By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be made much larger than that of non-liquid crystal materials, so the thickness of the retardation layer can be adjusted to obtain the desired in-plane retardation. can be made significantly smaller. As a result, it is possible to further reduce the thickness of the polarizing plate with a retardation layer. In this embodiment, rod-shaped liquid crystal compounds are typically aligned in the slow axis direction of the retardation layer (homogeneous alignment).

Examples of the liquid crystal compound include a liquid crystal compound whose liquid crystal phase is a nematic phase (nematic liquid crystal). As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The mechanism for developing liquid crystallinity of a liquid crystal compound may be either lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a crosslinkable monomer. This is because the alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (that is, curing) the liquid crystal monomer. After aligning the liquid crystal monomers, for example, by polymerizing or crosslinking the liquid crystal monomers, the alignment state can be fixed. Here, a polymer is formed by polymerization, and a three-dimensional network structure is formed by crosslinking, but these are non-liquid crystalline. Therefore, the formed retardation layer does not undergo transition to a liquid crystal phase, a glass phase, or a crystalline phase due to a temperature change, which is characteristic of liquid crystal compounds, for example. As a result, the retardation layer becomes an extremely stable retardation layer that is not affected by temperature changes.

The temperature range in which a liquid crystal monomer exhibits liquid crystallinity varies depending on its type. Specifically, the temperature range is preferably 40°C to 120°C, more preferably 50°C to 100°C, and most preferably 60°C to 90°C.

Any suitable liquid crystal monomer may be employed as the liquid crystal monomer. For example, the Synthetic mesogenic compounds etc. can be used. Specific examples of such polymerizable mesogenic compounds include, for example, BASF's product name LC242, Merck's product name E7, and Wacker-Chem's product name LC-Sillicon-CC3767. As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferable.

The alignment solidified layer of a liquid crystal compound is obtained by subjecting the surface of a predetermined base material to an alignment treatment, applying a coating liquid containing a liquid crystal compound to the surface to align the liquid crystal compound in a direction corresponding to the alignment treatment, It can be formed by fixing the orientation state. In one embodiment, the base material is any suitable resin film, and the alignment solidified layer formed on the base material can be transferred to the surface of the polarizing plate 10. In another embodiment, the substrate may be the second protective layer 13. In this case, the transfer step is omitted and lamination can be performed continuously by roll-to-roll from the formation of the orientation solidified layer (retardation layer), so that productivity is further improved.

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 at which it 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 oriented as described above. When the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the alignment state is fixed by subjecting the liquid crystal compound oriented as described above to a polymerization treatment or a crosslinking treatment.

Specific examples of the liquid crystal compound and details of the method for forming the alignment solidified layer are described in, for example, JP-A No. 2006-163343. The description of the publication is incorporated herein by reference.

In one embodiment, the retardation layer 20 is a single layer of an alignment solidified layer of a liquid crystal compound as shown in FIGS. 1 and 2. When the retardation layer 20 is composed of a single layer of an alignment solidified layer of a liquid crystal compound, its thickness is preferably 0.5 μm to 7 μm, more preferably 1 μm to 5 μm. By using a liquid crystal compound, it is possible to achieve an in-plane retardation equivalent to that of a resin film with a thickness much thinner than that of a resin film.

The retardation layer typically exhibits a refractive index characteristic of nx>ny=nz. The retardation layer is typically provided to impart antireflection properties to the polarizing plate, and can function as a λ/4 plate when the retardation layer is a single layer of the alignment fixed layer. In this case, the in-plane retardation Re (550) of the retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, even more preferably 130 nm to 160 nm. Note that "ny=nz" here includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there may be cases where ny>nz or ny<nz as long as the effects of the present invention are not impaired.

The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, more preferably 0.9 to 1.3. By satisfying such a relationship, when the obtained polarizing plate with a retardation layer is used in an image display device, an extremely excellent reflected hue can be achieved.

The retardation layer may exhibit inverse dispersion wavelength characteristics in which the retardation value increases depending on the wavelength of the measurement light, or may exhibit positive wavelength dispersion characteristics in which the retardation value decreases in accordance with the wavelength of the measurement light. Often, the phase difference value may exhibit flat wavelength dispersion characteristics that hardly change depending on the wavelength of the measurement light. In one embodiment, the retardation layer exhibits inverse dispersion wavelength characteristics. In this case, Re(450)/Re(550) of the retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and 0.95 or less. With such a configuration, extremely excellent antireflection properties can be achieved.

The angle θ between the slow axis of the retardation layer 20 and the absorption axis of the polarizer 11 is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°. be. If the angle θ is in this range, by using a λ/4 plate as the retardation layer as described above, it will have very good circular polarization properties (as a result, very good anti-reflection properties). A polarizing plate with a retardation layer can be obtained.

In another embodiment, the retardation layer 20 may have a laminated structure of a first alignment fixed layer 21 and a second alignment fixed layer 22, as shown in FIG. In this case, either the first orientation fixed layer 21 or the second orientation fixed layer 22 may function as a λ/4 plate, and the other may function as a λ/2 plate. Therefore, the thicknesses of the first alignment fixed layer 21 and the second alignment fixed layer 22 can be adjusted so as to obtain a desired in-plane retardation of the λ/4 plate or the λ/2 plate. For example, when the first oriented solidified layer 21 functions as a λ/2 plate and the second oriented solidified layer 22 functions as a λ/4 plate, the thickness of the first oriented solidified layer 21 is, for example, 2.0 μm or more. The thickness of the second alignment fixed layer 22 is, for example, 1.0 μm to 2.0 μm. In this case, the in-plane retardation Re(550) of the first alignment fixed layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and still more preferably 250 nm to 280 nm. The in-plane retardation Re (550) of the second alignment fixed layer is as explained above for the single layer alignment fixed layer. The angle between the slow axis of the first alignment solidified layer and the absorption axis of the polarizer is preferably 10° to 20°, more preferably 12° to 18°, and still more preferably about 15°. be. The angle between the slow axis of the second alignment solidified layer and the absorption axis of the polarizer is preferably 70° to 80°, more preferably 72° to 78°, and still more preferably about 75°. be. With such a configuration, it is possible to obtain characteristics close to ideal reverse wavelength dispersion characteristics, and as a result, extremely excellent antireflection characteristics can be realized. Regarding the liquid crystal compounds constituting the first alignment fixed layer and the second alignment fixed layer, the formation method of the first alignment fixed layer and the second alignment fixed layer, optical properties, etc., please refer to the above for the single layer alignment fixed layer. As explained in .

D. Adhesive Layer The first adhesive layer and the second adhesive layer will be collectively described as an adhesive layer. Note that the first adhesive layer and the second adhesive layer may have the same configuration or may have mutually different configurations. As the adhesive constituting the adhesive layer, any suitable adhesive that can penetrate the alignment solidified layer of the liquid crystal compound to form a permeation layer can be employed. Typical examples of the adhesive include active energy ray-curable adhesives. Examples of active energy ray curable adhesives include ultraviolet ray curable adhesives and electron beam curable adhesives. From the viewpoint of the curing mechanism, active energy ray-curable adhesives include, for example, radical-curable adhesives, cation-curable adhesives, anion-curable adhesives, and hybrids of radical-curable and cationic-curable adhesives. Typically, a radical-curable ultraviolet curable adhesive may be used. This is because it has excellent versatility and its characteristics (configuration) can be easily adjusted.

The adhesive typically contains a curing component and a photopolymerization initiator. The curing component typically includes monomers and/or oligomers having functional groups such as (meth)acrylate groups and (meth)acrylamide groups. Specific examples of curing components include tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecanedimethanol diacrylate, phenoxydiethylene glycol acrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, and EO modification. Diglycerin tetraacrylate, γ-butyrolactone acrylate, acryloylmorpholine, unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone, N-methylpyrrolidone, hydroxyethylacrylamide, N-methylolacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide Can be mentioned. These curing components may be used alone or in combination of two or more.

Preferably, the adhesive includes a curing component having a heterocycle. Examples of the curing component having a heterocycle include acryloylmorpholine, γ-butyrolactone acrylate, unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone, and N-methylpyrrolidone. More preferred curing components are unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone and acryloylmorpholine, and a particularly preferred curing component is acryloylmorpholine. The curing component having a heterocycle is preferably 50 parts by weight or more, more preferably 60 parts by weight, based on 100 parts by weight of the curing component (the total of the curing component and oligomer component if an oligomer component described below is present). More preferably, it may be contained in the adhesive in an amount of 70 to 95 parts by weight. Acryloylmorpholine is preferably 5 parts by weight to 60 parts by weight, more preferably 10 parts by weight to 50 parts by weight, based on 100 parts by weight of the curing component (the total of the curing component and oligomer component if an oligomer component is present). may be included in the adhesive.

The adhesive may further contain an oligomer component in addition to the above-mentioned curing component. By using the oligomer component, the viscosity of the adhesive before curing can be reduced and the operability can be improved. A typical example of the oligomer component is a (meth)acrylic oligomer. Examples of (meth)acrylic monomers constituting the (meth)acrylic oligomer include (meth)acrylic acid (carbon number 1 to 20) alkyl esters, cycloalkyl (meth)acrylates (such as cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, etc.), aralkyl (meth)acrylates (e.g., benzyl (meth)acrylate, etc.), polycyclic (meth)acrylates (e.g., 2-isobornyl (meth)acrylate, 2-norbornylmethyl (meth)acrylate, etc. ) acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc.), hydroxyl group-containing (meth)acrylic esters (for example, hydroxyethyl ( (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), (meth)acrylic acid esters containing an alkoxy group or phenoxy group (2-methoxyethyl (meth)acrylate, etc.) Acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic esters (e.g., glycidyl (meth)acrylate, etc.), halogen-containing (meth)acrylic esters (e.g., 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2- trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, etc.), alkylaminoalkyl (meth)acrylate Acrylates (eg, dimethylaminoethyl (meth)acrylate, etc.) can be mentioned. Specific examples of (meth)acrylic acid (1 to 20 carbon atoms) alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and 2-methyl -2-Nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t- Pentyl (meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, and n-octadecyl (meth)acrylate. These (meth)acrylates may be used alone or in combination of two or more.

A detailed description of the photopolymerization initiator will be omitted since photopolymerization initiators well known in the industry can be used in amounts well known in the industry.

The thickness of the adhesive layer (after the adhesive is cured) is preferably 0.1 μm to 3.0 μm. By applying the adhesive to such a thickness, a permeable layer with an appropriate thickness can be formed.

Details of the adhesive are described in, for example, Japanese Patent Application Publication No. 2018-017996. The description of the publication is incorporated herein by reference.

E. Another Retardation Layer The other retardation layer may be a so-called positive C plate whose refractive index characteristics exhibit the relationship nz>nx=ny, as described above. By using a positive C plate as another retardation layer, reflection in an oblique direction can be effectively prevented, and the antireflection function can provide a wide viewing angle. In this case, the retardation Rth (550) in the thickness direction of another retardation layer is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, still more preferably -90 nm to -200 nm, particularly preferably - It is 100 nm to -180 nm. Here, "nx=ny" includes not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. That is, the in-plane retardation Re(550) of another retardation layer may be less than 10 nm.

Another retardation layer having a refractive index characteristic of nz>nx=ny may be formed of any suitable material. The further retardation layer preferably consists of a film containing liquid crystal material fixed in a homeotropic alignment. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the retardation layer include the liquid crystal compound and the method for forming the retardation layer described in [0020] to [0028] of JP-A No. 2002-333642. In this case, the thickness of the other retardation layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and even more preferably 0.5 μm to 5 μm.

F. Conductive layer or isotropic base material with conductive layer The conductive layer can be formed on any suitable base material by any suitable film forming method (e.g., vacuum evaporation method, sputtering method, CVD method, ion plating method, spray method, etc.). It can be formed by depositing a metal oxide film thereon. Examples of metal oxides include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Among them, indium-tin composite oxide (ITO) is preferred.

When the conductive layer contains a metal oxide, the thickness of the conductive layer is preferably 50 nm or less, more preferably 35 nm or less. The lower limit of the thickness of the conductive layer is preferably 10 nm.

The conductive layer may be transferred from the base material to the retardation layer (or another retardation layer if present), and the conductive layer alone may be a constituent layer of the polarizing plate with a retardation layer. The retardation layer (or another retardation layer if present) may be laminated as a laminate (conductive layer-attached base material) with the retardation layer. Preferably, the base material is optically isotropic, and therefore, the conductive layer can be used as an isotropic base material with a conductive layer in a polarizing plate with a retardation layer.

Any suitable isotropic base material can be employed as the optically isotropic base material (isotropic base material). Materials constituting the isotropic base material include, for example, materials whose main skeleton is a resin without a conjugated system such as norbornene resins and olefin resins, and materials with cyclic structures such as lactone rings and glutarimide rings such as acrylic resins. Examples include materials contained in the main chain. When such a material is used, when an isotropic base material is formed, the development of retardation due to the orientation of molecular chains can be suppressed to a small level. The thickness of the isotropic base material is preferably 50 μm or less, more preferably 35 μm or less. The lower limit of the thickness of the isotropic base material is, for example, 20 μm.

The conductive layer and/or the conductive layer of the isotropic base material with a conductive layer may be patterned as necessary. A conductive part and an insulating part can be formed by patterning. As a result, an electrode can be formed. The electrode can function as a touch sensor electrode that senses contact with the touch panel. Any suitable method can be adopted as the patterning method. Specific examples of patterning methods include wet etching and screen printing.

G. Image display device The polarizing plate with a retardation layer described in the above items A to F can be applied to an image display device. Therefore, the present invention includes an image display device using such a polarizing plate with a retardation layer. Typical examples of image display devices include liquid crystal display devices and electroluminescence (EL) display devices (eg, organic EL display devices, and inorganic EL display devices (eg, quantum dot display devices)). The image display device according to the embodiment of the present invention includes the polarizing plate with a retardation layer described in the above items A to F on the viewing side. The polarizing plate with a retardation layer is laminated so that the retardation layer is on the image display cell (eg, liquid crystal cell, organic EL cell, inorganic EL cell) side (with the polarizer on the viewing side). In one embodiment, the image display device has a curved shape (substantially a curved display screen) and/or is bendable or foldable. In such an image display device, the effect of the polarizing plate with a retardation layer of the present invention becomes remarkable.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. The method for measuring each characteristic is as follows. Note that unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are based on weight.

[Manufacture example 1]
50 parts of unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (“Plaxel FA1DDM” manufactured by Daicel), 40 parts of acryloylmorpholine (“ACMO (registered trademark)” manufactured by Kojinsha), acrylic oligomer (“ARFON” manufactured by Toagosei Co., Ltd.) UP-1190''), 3 parts of ``KAYACURE DETX-S'' (manufactured by Nippon Kayaku Co., Ltd.) as a photopolymerization initiator, and 3 parts of OMNIRAD907 (IGM Resins Italia S.r.l.) were mixed and bonded. Agent A was prepared.

[Manufacture example 2]
50 parts of unsaturated fatty acid hydroxyalkyl ester-modified ε-caprolactone (“Plaxel FA1DDM” manufactured by Daicel), 40 parts of phenoxydiethylene glycol acrylate (“Light Acrylate P2H-A” manufactured by Kyoeisha Chemical Co., Ltd.), acrylic oligomer (“ARFON” manufactured by Toagosei Co., Ltd.) UP-1190''), 3 parts of ``KAYACURE DETX-S'' (manufactured by Nippon Kayaku Co., Ltd.) as a photopolymerization initiator, and 3 parts of OMNIRAD907 (IGM Resins Italia S.r.l.) were mixed and bonded. Agent B was prepared.

[Example 1]
1. Preparation of polarizing plate A-PET (amorphous polyethylene terephthalate) film (manufactured by Mitsubishi Plastics Co., Ltd., product name: Novaclear SH046, thickness 200 μm) was prepared as a base material, and the surface was corona treated (58 W/m2/min). did. On the other hand, 1 wt% of acetoacetyl-modified PVA (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., trade name: Gosefimer Z200, degree of polymerization 1200, degree of saponification 99.0% or more, degree of acetoacetyl modification 4.6%) was added. Prepare PVA (polymerization degree 4200, saponification degree 99.2%), apply it so that the film thickness after drying is 12 μm, dry it for 10 minutes with hot air drying in an atmosphere of 60 ° C. A laminate in which a PVA resin layer was provided on the material was produced. Next, this laminate was first stretched 2.0 times in air at 130°C to obtain a stretched laminate. Next, the stretched laminate was immersed in a boric acid insolubilizing aqueous solution at a liquid temperature of 30° C. for 30 seconds to insolubilize the PVA-based resin layer in which the PVA molecules contained in the stretched laminate were oriented. The boric acid insolubilized aqueous solution used in this step had a boric acid content of 3% by weight based on 100% by weight of water. A colored laminate was produced by dyeing this stretched laminate. The colored laminate is obtained by immersing the stretched laminate in a dye solution containing iodine and potassium iodide at a liquid temperature of 30° C. so that iodine is adsorbed onto the PVA resin layer contained in the stretched laminate. The iodine concentration and immersion time were adjusted so that the single transmittance of the obtained polarizer was 44.5%. Specifically, the staining solution was made using water as a solvent, with an iodine concentration in the range of 0.08 to 0.25% by weight, and a potassium iodide concentration in the range of 0.56 to 1.75% by weight. . The ratio of iodine to potassium iodide concentrations was 1:7. Next, the colored laminate was immersed in a boric acid crosslinking aqueous solution at 30° C. for 60 seconds to crosslink the PVA molecules of the PVA resin layer on which iodine had been adsorbed. The boric acid crosslinking aqueous solution used in this step had a boric acid content of 3% by weight based on 100% water, and a potassium iodide content of 3% by weight based on 100% water. Furthermore, the obtained colored laminate was stretched in a boric acid aqueous solution at a stretching temperature of 70°C to 2.7 times in the same direction as in the above stretching in air, and the final stretching ratio was 5.4. As a double layer, a base material/polarizer laminate was obtained. The thickness of the polarizer was 5 μm. The boric acid crosslinking aqueous solution used in this step had a boric acid content of 6.5% by weight based on 100% water, and a potassium iodide content of 5% by weight based on 100% water. The obtained laminate was taken out of the boric acid aqueous solution, and the boric acid adhering to the surface of the polarizer was washed with an aqueous solution having a potassium iodide content of 2% by weight based on 100% by weight of water. The washed laminate was dried with warm air at 60°C.
A triacetyl cellulose (TAC) film with a thickness of 40 μm was attached to the polarizer surface of the base material/polarizer laminate obtained above via a PVA adhesive, and a protective layer (TAC film)/polarizer A laminate having a structure of /resin base material was obtained. Furthermore, the resin base material is peeled off from this laminate, and a TAC film with a thickness of 40 μm is laminated to the peeled surface to form a laminate ( polarizing plate) was obtained.

ポリエチレンテレフタレート（ＰＥＴ）フィルム（厚み３８μｍ）表面を、ラビング布を用いてラビングし、配向処理を施した。配向処理の方向は、偏光板に貼り合わせる際に偏光子の吸収軸の方向に対して視認側から見て４５°方向となるようにした。この配向処理表面に、上記液晶塗工液をバーコーターにより塗工し、９０℃で２分間加熱乾燥することによって液晶化合物を配向させた。このようにして形成された液晶層に、メタルハライドランプを用いて１ｍＪ/ｃｍ^２の光を照射し、当該液晶層を硬化させることによって、ＰＥＴフィルム上に液晶配向固化層Ａを形成した。液晶配向固化層Ａの厚みは１．５μｍ、面内位相差Ｒｅ（５５０）は１４０ｎｍであった。さらに、液晶配向固化層Ａは、ｎｘ＞ｎｙ＝ｎｚの屈折率分布を有していた。 2. Preparation of an alignment solidified layer of a liquid crystal compound constituting a retardation layer 10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF, trade name "Paliocolor LC242", represented by the following formula) and a A liquid crystal composition (coating liquid) was prepared by dissolving 3 g of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 907") in 40 g of toluene.

The surface of a polyethylene terephthalate (PET) film (thickness: 38 μm) was rubbed using a rubbing cloth to perform orientation treatment. The direction of the alignment treatment was set to be 45° when viewed from the viewing side with respect to the direction of the absorption axis of the polarizer when bonding to the polarizing plate. The above-mentioned liquid crystal coating solution was applied to this alignment-treated surface using a bar coater, and the liquid crystal compound was aligned by heating and drying at 90° C. for 2 minutes. The thus formed liquid crystal layer was irradiated with light of 1 mJ/cm ² using a metal halide lamp to cure the liquid crystal layer, thereby forming a liquid crystal alignment solidified layer A on the PET film. The thickness of the liquid crystal alignment solidified layer A was 1.5 μm, and the in-plane retardation Re (550) was 140 nm. Furthermore, the liquid crystal alignment solidified layer A had a refractive index distribution of nx>ny=nz.

3. Preparation of polarizing plate with retardation layer 1. The above 2. is applied to the surface of the polarizing plate obtained in 2. The liquid crystal alignment solidified layer A obtained in Example 1 was transferred via the adhesive A obtained in Production Example 1 (thickness after curing: 1.0 μm). In this way, the protective layer (TAC film) / polarizer / protective layer (TAC film) / adhesive layer (adhesive A) / retardation layer (liquid crystal alignment solidified layer A, λ/4 plate, slow axis 45 A polarizing plate with a retardation layer having a configuration in the direction (° direction) was obtained. When the cross section of the obtained polarizing plate with a retardation layer was observed using a transmission electron microscope (TEM), it was found that the adhesive A had penetrated into both the retardation layer (liquid crystal alignment solidified layer A) and the protective layer (TAC film). A permeable layer was observed. FIG. 4 shows a TEM image showing the state of the interface between the adhesive layer and the retardation layer (liquid crystal alignment solidified layer A).

4. Evaluation of releasability The releasability of the obtained polarizing plate with a retardation layer was evaluated. Specifically, the details are as follows. The obtained polarizing plate with a retardation layer was cut into a size of 200 mm in parallel to the absorption axis direction of the polarizer and 15 mm in the orthogonal direction, and bonded to a glass plate. A peel test was conducted in a 90° direction at a peel rate of 300 mm/min using a Tensilon universal testing machine RTC manufactured by A&D Co., Ltd., and the peel strength at that time was measured. In the peel test, peeling occurred at the interface between the TAC film and the adhesive layer, and the peel strength was 0.8 N/15 mm.

[Example 2]
In the production of the polarizing plate, the protective layer (TAC film)/polarizer/ Obtain a polarizing plate with a retardation layer having a configuration of a protective layer (COP film)/adhesive layer (adhesive A)/retardation layer (liquid crystal alignment solidified layer A, λ/4 plate, slow axis 45° direction) Ta. When the cross section of the obtained polarizing plate with a retardation layer was observed with a transmission electron microscope (TEM), a permeation layer formed by the adhesive A permeating into the retardation layer (liquid crystal alignment solidified layer A) was confirmed. Ta. Furthermore, the peelability of the obtained polarizing plate with a retardation layer was evaluated in the same manner as in Example 1. In the peel test, peeling occurred at the interface between the retardation layer (liquid crystal alignment solidified layer A) and the adhesive layer, and the peel strength was 0.7 N/15 mm.

[Example 3]
In manufacturing the polarizing plate, the protective layer (TAC film)/polarizer/protective layer (acrylic A polarizing plate with a retardation layer having a configuration of (film)/adhesive layer (adhesive A)/retardation layer (liquid crystal alignment solidified layer A, λ/4 plate, slow axis 45° direction) was obtained. When the cross section of the obtained polarizing plate with a retardation layer was observed with a transmission electron microscope (TEM), a permeation layer formed by the adhesive A permeating into the retardation layer (liquid crystal alignment solidified layer A) was confirmed. Ta. Furthermore, the peelability of the obtained polarizing plate with a retardation layer was evaluated in the same manner as in Example 1. In the peel test, peeling occurred at the interface between the acrylic film and the adhesive layer, and the peel strength was 0.3 N/15 mm.

[Example 4]
In the production of the polarizing plate, the protective layer (TAC film)/polarizer/adhesive layer (adhesive A)/retardation was prepared in the same manner as in Example 1 except that the protective layer was not provided on the peeling surface of the resin base material. A polarizing plate with a retardation layer having a structure of layers (liquid crystal alignment solidified layer A, λ/4 plate, slow axis in 45° direction) was obtained. When the cross section of the obtained polarizing plate with a retardation layer was observed with a transmission electron microscope (TEM), a permeation layer formed by the adhesive A permeating into the retardation layer (liquid crystal alignment solidified layer A) was confirmed. Ta. Furthermore, the peelability of the obtained polarizing plate with a retardation layer was evaluated in the same manner as in Example 1. In the peel test, no peeling occurred.

[Example 5]
A polarizing plate having a protective layer (TAC film)/polarizer structure was obtained in the same manner as in Example 4. Here, the procedure was the same as in Example 1, except that the coating thickness was changed and the orientation treatment direction was set at 15 degrees when viewed from the viewing side with respect to the direction of the absorption axis of the polarizer. , a liquid crystal alignment solidified layer B was formed on the PET film. The thickness of the liquid crystal alignment solidified layer B was 2.5 μm, and the in-plane retardation Re (550) was 270 nm. The liquid crystal alignment solidified layer B is transferred to the polarizer surface of the polarizing plate via the adhesive A (thickness 1.0 μm after curing), and the alignment treatment direction is set on the viewing side with respect to the direction of the absorption axis of the polarizer. Liquid crystal alignment solidified layer A, which was prepared in the same manner as in Example 1 except that the direction was 75° when viewed from transferred onto the surface of In this way, the protective layer (TAC film) / polarizer / adhesive layer (adhesive A) / liquid crystal alignment solidified layer B (λ/2 plate, slow axis 15° direction) / adhesive layer (adhesive A )/liquid crystal alignment fixed layer A (λ/4 plate, slow axis 75° direction). A polarizing plate with a retardation layer was obtained. When the cross section of the obtained polarizing plate with a retardation layer was observed with a transmission electron microscope (TEM), it was found that a permeation layer was formed by the adhesive A permeating into both the liquid crystal alignment solidified layer A and the liquid crystal alignment solidified layer B. was confirmed. Furthermore, the peelability of the obtained polarizing plate with a retardation layer was evaluated in the same manner as in Example 1. In the peel test, the adhesive layer between the liquid crystal alignment solidified layer A and the liquid crystal alignment solidified layer B suffered cohesive failure.

[Comparative example 1]
Protective layer (TAC film)/polarizer/adhesive was prepared in the same manner as in Example 4 except that adhesive B obtained in Production Example 2 (thickness 1.0 μm after curing) was used instead of adhesive A. A polarizing plate with a retardation layer having a configuration of adhesive layer (adhesive B)/retardation layer (liquid crystal alignment solidified layer A, λ/4 plate, slow axis 45° direction) was obtained. When the cross section of the obtained polarizing plate with a retardation layer was observed using a transmission electron microscope (TEM), no permeation layer was observed. FIG. 5 shows a TEM image showing the state of the interface between the adhesive layer and the retardation layer (liquid crystal alignment solidified layer A). Furthermore, the peelability of the obtained polarizing plate with a retardation layer was evaluated in the same manner as in Example 1. In the peel test, peeling occurred at the interface between the liquid crystal alignment solidified layer A and the adhesive layer, and the peel strength was 0.5 N/15 mm.

[evaluation]
As is clear from comparing the Examples and Comparative Examples, the Examples of the present invention can suppress peeling of the liquid crystal alignment solidified layer.

The polarizing plate with a retardation layer of the present invention is suitably used as a circularly polarizing plate for liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

10 Polarizing plate 11 Polarizer 12 First protective layer 13 Second protective layer 20 Retardation layer 20a Permeation layer 21 First orientation solidified layer 21a Permeation layer 22 Second orientation solidification layer 22a Permeation layer 31 First adhesive Agent layer 32 Second adhesive layer 100 Polarizing plate with retardation layer 101 Polarizing plate with retardation layer 102 Polarizing plate with retardation layer

Claims (1)

A polarizing plate including a polarizer and a protective layer on at least one side of the polarizer, and a retardation layer laminated on the polarizing plate via a first adhesive layer, the retardation layer an oriented solidified layer of a liquid crystal compound, including a permeation layer formed by penetration of the adhesive of the first adhesive layer near the interface with the first adhesive layer;
Polarizing plate with retardation layer.

Images