TW202327865A - Retardation layer-equipped polarizing plate and image display device including retardation layer-equipped polarizing plate - Google Patents

Abstract

The purpose of the present invention is to provide a retardation layer-equipped polarizing plate having excellent high-temperature durability. A retardation layer-equipped polarizing plate according to an embodiment of the present invention comprises: a polarizing plate including a polarizer with a thickness of 7 [mu]m or more; a first retardation layer being an alignment fixed layer of a liquid crystal compound; and a second retardation layer comprising a resin film including a polymer that exhibits negative birefringence.

Description

Polarizing plate with phase difference layer and image display device including the polarizing plate with phase difference layer

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

In recent years, image display devices typified by liquid crystal display devices and electroluminescent (EL) display devices (such as organic EL display devices and inorganic EL display devices) are rapidly spreading. Typically, a polarizing plate and a retardation plate are used in an image display device. From a practical point of view, a polarizing plate with a retardation layer in which a polarizing plate and a retardation plate are integrated is widely used (for example, Patent Document 1). As the demand for thinner image display devices increases, the demand for thinner polarizers with retardation layers is also increasingly strong. In order to realize the thinning of the polarizing plate with the retardation layer, the thinning of the retardation plate is being continuously developed, and the retardation plate made of a liquid crystal material is used. Regarding the thin retardation plate, the size shrinkage of the polarizer tends to increase under high temperature conditions, and the retardation may change. In addition, in the retardation layer formed of a liquid crystal material, the effect of dimensional shrinkage is greater, and as a result, the reflection hue may further change. prior art literature patent documents

Patent Document 1: Japanese Patent No. 3325560

[Problem to be solved by the invention]

The present invention was made to solve the aforementioned problems, and its main object is to provide a polarizing plate with a retardation layer that suppresses in-plane unevenness in reflection hue and is excellent in high-temperature durability. [Technical means to solve the problem]

A polarizing plate with a retardation layer according to an embodiment of the present invention has: a polarizing plate including a polarizing element with a thickness of 7 μm or more; a first retardation layer which is an alignment solidified layer of a liquid crystal compound; and a second retardation layer , which consists of a resin film comprising a polymer exhibiting negative birefringence. In one embodiment, the second retardation layer is adjacent to the first retardation layer. In one embodiment, the second retardation layer is a positive C plate. In one embodiment, the thickness of the second retardation layer is 1 μm˜30 μm. In one embodiment, the polymer exhibiting negative birefringence is at least one selected from the group consisting of acrylic resins, styrene resins, and maleimide resins. In one embodiment, the in-plane retardation of the first retardation layer is 100 nm<Re(550)<160 nm, and Re(450)/Re(550)<1, and Re(650)/Re (550)>1. In one embodiment, the angle formed by the slow axis of the first retardation layer and the absorption axis of the polarizer is 40°-50°. In one embodiment, the above-mentioned first phase layer has a laminated structure of an alignment solidified layer A of a liquid crystal compound and an alignment solidified layer B of a liquid crystal compound, and the alignment solidified layer A functions as a λ/2 plate, and the alignment solidified layer B functions as a λ/4 plate. In one embodiment, the angle formed by the slow axis of the alignment-cured layer A of the above-mentioned liquid crystal compound and the absorption axis of the above-mentioned polarizer is 70°-80°, and the slow axis of the alignment-cured layer B of the above-mentioned liquid crystal compound and the above-mentioned polarizer The angle formed by the absorption axes of the elements is 10°-20°. In another aspect of the present invention, an image display device is provided. The image display device includes the above-mentioned polarizing plate with a retardation layer. [Effect of Invention]

According to an embodiment of the present invention, it is possible to provide a polarizing plate with a retardation layer that suppresses in-plane unevenness in reflection hue and is excellent in high-temperature durability. According to the embodiment of the present invention, even in a polarizing plate with a retardation layer including a retardation layer as a liquid crystal alignment solidified layer, the retardation change of the polarizing plate under a high temperature environment is suppressed. Therefore, changes in the reflection hue can also be suppressed. As a result, it is possible to provide a polarizing plate with a retardation layer which suppresses in-plane unevenness of reflection hue and has excellent high-temperature durability.

Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

(Definition of terms and symbols) Definitions of terms and symbols in this manual are as follows. (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction of the maximum refractive index in the plane (that is, the direction of the slow axis), "ny" is the refractive index in the direction perpendicular to the slow axis in the plane (that is, the direction of the fast axis), and "nz" is the thickness direction of refraction. (2) In-plane retardation (Re) "Re(λ)" is the in-plane retardation measured at 23°C with light of wavelength λ nm. For example, "Re(550)" is the in-plane retardation measured at 23°C using light with a wavelength of 550 nm. When the thickness of the layer (film) is d (nm), Re(λ) is obtained from the formula: Re(λ)=(nx-ny)×d. (3) Phase difference in thickness direction (Rth) "Rth(λ)" is the retardation in the thickness direction measured at 23°C using light with a wavelength of λ nm. For example, "Rth(550)" is the retardation in the thickness direction measured at 23°C by using light with a wavelength of 550 nm. When the thickness of the layer (film) is d (nm), Rth(λ) is obtained from the formula: Rth(λ)=(nx-nz)×d. (4) Nz coefficient The Nz coefficient is obtained by Nz=Rth/Re. (5) angle When angles are mentioned in this specification, the angles include angles in both clockwise and counterclockwise directions relative to the reference direction. Thus, for example, "45°" means ±45°.

A. Overall composition of polarizing plate with retardation layer FIG. 1 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to an embodiment of the present invention. The polarizing plate 100 with a retardation layer shown in the illustration has a polarizing plate 10 , a first retardation layer 20 , and a second retardation layer 30 in this order from the viewing side. The polarizing plate 10 typically includes a polarizing element 11 and protective layers 12 and 13 disposed on both sides of the polarizing element 11 . The protective layer 13 can also be omitted. Each member constituting the polarizing plate with a retardation layer can be laminated via any appropriate adhesive layer (not shown). Specific examples of the adhesive layer include an adhesive layer and an adhesive layer. The first retardation layer 20 is an alignment solidified layer of a liquid crystal compound (hereinafter, sometimes simply referred to as a liquid crystal alignment solidified layer). The second retardation layer 30 is composed of a resin film containing a polymer exhibiting negative birefringence. In the illustrated example, the first retardation layer 20 is a single layer. By having the first retardation layer 20 as a liquid crystal alignment solidified layer, and the second retardation layer 30 composed of a resin film containing a polymer showing negative birefringence, it is possible to provide an in-plane unevenness of reflection hue Polarizing plate with retardation layer with excellent high temperature durability and suppression. The first retardation layer, which is the liquid crystal alignment solidification layer, is easily affected by the shrinkage of the polarizing plate in a high-temperature environment, and the retardation may change. Therefore, the reflection hue of the polarizing plate with a retardation layer changes, and in-plane unevenness of the reflection hue may occur. By having the second retardation layer made of a resin film containing a polymer showing negative birefringence, the influence of dimensional shrinkage of the polarizing plate on the first retardation layer can be alleviated. As a result, changes in the retardation of the first retardation layer can be suppressed. In addition, the second retardation layer is made of a resin film containing a polymer exhibiting negative birefringence, thereby reducing a change in retardation due to dimensional shrinkage of the polarizing plate under a high-temperature environment. Therefore, the retardation change of the polarizing plate with the retardation layer is suppressed in a high-temperature environment, and the in-plane reflection color unevenness can be further suppressed. The first retardation layer 20 and the second retardation layer 30 are preferably adjacent to each other. By adjoining the first retardation layer, which is a liquid crystal alignment solidified layer, and the second retardation layer made of a resin film, it is possible to provide a product with further suppressed in-plane unevenness in reflection hue and excellent high-temperature durability. Polarizing plate with retardation layer. In this specification, the term "adjacent" includes not only direct adjacency but also adjacency via any adhesive layer. In this specification, "liquid crystal alignment solidified layer" refers to a layer in which liquid crystal compounds are aligned along a specific direction within the layer, and the alignment state is fixed. In addition, the "alignment hardened layer" is a concept including an alignment hardened layer obtained by hardening a liquid crystal monomer as described below.

In the illustrated example, although there is a second retardation layer 30 on the area layer of the first retardation layer 20 that is not in contact with the polarizing plate 10, the second retardation layer 30 can also be arranged on the polarizing plate 10 and the first retardation layer. Between 20.

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 polarizing plate 101 with a retardation layer shown in the illustration, the polarizing plate 10, the first retardation layer 20 as a liquid crystal alignment solidification layer, and a resin composed of a polymer showing negative birefringence are provided in order from the viewing side. The second retardation layer 30 composed of a film. In the illustrated example, the first retardation layer 20 has a laminated structure of a liquid crystal alignment solidified layer A21 and a liquid crystal alignment solidified layer B22. Even though a liquid crystal alignment solidified layer having a laminated structure is used as the first retardation layer 20, it is possible to provide a polarizing plate with a retardation layer that suppresses in-plane unevenness of reflection hue and has excellent high-temperature durability. In the illustrated example, although the liquid crystal alignment solidified layer B22 is disposed adjacent to the second retardation layer 30 , the second retardation layer 30 may also be disposed between the polarizer 10 and the liquid crystal alignment solidified layer A21 .

In one embodiment, the polarizing plates 100 and 101 with a retardation layer are provided with an adhesive layer on the outermost layer (for example, the surface on which the first retardation layer 20 is not laminated on the second retardation layer 30 in the illustrated example ), and can be attached to an image display device (essentially an image display unit). From a practical point of view, the surface of the adhesive layer is preferably temporarily bonded with a release liner before using the polarizing plate. By temporarily adhering the release liner, the adhesive layer can be properly protected.

The polarizing plate with a retardation layer may further be provided with another retardation layer (not shown) different from the first retardation layer 20 and the second retardation layer 30 . Other retardation layers are any layers that can be provided as needed, and can also be omitted. The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, etc. of other retardation layers can be appropriately set according to the purpose.

In the polarizing plate with a retardation layer, the ratio of the thickness of the polarizing element to the thickness of the first retardation layer, for example, the thickness of the polarizing element/thickness of the first retardation layer is 0.5-7, preferably 1-6 , and more preferably 2-5. According to the embodiment of the present invention, even in such a polarizing plate with a retardation layer, the change of the retardation caused by the dimensional shrinkage in a high-temperature environment is suppressed, and the change of the reflection hue can also be suppressed.

The total thickness of the polarizing plate with retardation layer is preferably from 40 μm to 120 μm, more preferably from 40 μm to 110 μm, and still more preferably from 50 μm to 100 μm. A polarizing plate with a retardation layer including a polarizing plate having a certain thickness can have such a thickness. In the case of such a polarizing plate with a retardation layer, the influence of the dimensional shrinkage of the polarizing plate under a high temperature environment tends to be large. According to the embodiment of the present invention, even in the polarizing plate with the retardation layer having the above-mentioned thickness, the retardation change caused by the dimensional shrinkage in the high-temperature environment is suppressed, and the change of the reflection hue can also be suppressed. Furthermore, the total thickness of the polarizing plate with a retardation layer refers to the polarizing plate, the retardation layer (when there are other retardation layers, the retardation layer and other retardation layers), and the adhesive layer used to make the layers equal. The total thickness of the layers (that is, the total thickness of the polarizing plate with retardation layer does not include the thickness of the adhesive layer provided as the outermost layer and the release liner that can be temporarily bonded to its surface).

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

B. Polarizer B-1. Polarizing element A polarizing element is typically composed of a polyvinyl alcohol (PVA)-based resin film containing a dichroic substance. As mentioned above, the thickness of the polarizer is 7 μm or more, for example 8 μm or more, for example 10 μm or more, for example 12 μm or more, and for example 15 μm or more. When the thickness of the polarizing element is large, the size shrinkage of the polarizing plate with a retardation layer tends to increase, and the retardation change may become more significant. In an embodiment of the present invention, even when a polarizing element having the above-mentioned thickness is used, high-temperature durability is excellent, and a change in retardation due to dimensional shrinkage can be suppressed. As a result, it is possible to suppress reflection color unevenness in the plane of the polarizing plate with a retardation layer. The thickness of the polarizer is, for example, 30 μm or less.

The content of boric acid in the polarizing element is preferably 20% by weight or less, more preferably 5% by weight to 20% by weight, further preferably 10% by weight to 18% by weight. When the boric acid content of the polarizing element is within such a range, a polarizing plate with a retardation layer excellent in high temperature durability can be provided. When the content of boric acid is less than 5% by weight, the polarizing element may be polyeneized, and the durability may be lowered. According to the embodiments of the present invention, even when placed in a high-temperature environment, it is possible to suppress a change in phase difference due to dimensional shrinkage of the polarizing plate, and it is also possible to suppress a change in reflection hue. As a result, a polarizing plate with a retardation layer having an excellent reflection hue can be provided. The boric acid content of the polarizer can be adjusted, for example, by adjusting the boric acid content in the aqueous solution used in the following steps. The boric acid content can be calculated as the amount of boric acid contained in a polarizing element per unit weight using the following formula, for example, according to the neutralization method. [number 1]

The iodine content of the polarizing element is preferably at least 2% by weight, more preferably 2% to 10% by weight. If the iodine content of the polarizing element is within this range, the synergistic effect with the above-mentioned boric acid content can well maintain the ease of adjusting curling during lamination, and well suppress curling during heating, and Improve the durability of appearance when heated. In this specification, "iodine content" means the content of all iodine contained in a polarizing element (PVA-type resin film). More specifically, iodine exists in the form of iodide ion (I ^- ), iodine molecule (I ₂ ), polyiodide ion (I ₃ ^- , I ₅ ^- ) in the polarizing element, so the iodine content in this specification means including The content of iodine in all its forms. The iodine content can be calculated by the calibration curve method of fluorescent X-ray analysis, for example. Furthermore, in the polarizing element, polyiodide ions exist in the state of forming PVA-iodine complexes. By forming such complexes, absorption dichroism can be exhibited in the wavelength range of visible light. Specifically, the complex of PVA and triiodide ions (PVA-I ₃ ^- ) has an absorption peak near 470 nm, and the complex of PVA and pentaiodide ions (PVA-I ₅ ^- ) has an absorption peak near 600 nm. Has an absorption peak. As a result, polyiodide ions can absorb light in a wide range of visible light depending on their form. On the other hand, iodide ion (I ^- ) has an absorption peak around 230 nm, and does not substantially participate in the absorption of visible light. Therefore, polyiodide ions existing in the state of a complex with PVA can mainly participate in the absorption performance of the polarizer.

The polarizing element preferably exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The single transmittance Ts of the polarizing element is preferably 40%-48%, more preferably 41%-46%. The degree of polarization P of the polarizing element is preferably at least 97.0%, more preferably at least 99.0%, and still more preferably at least 99.9%. The above-mentioned monomer transmittance is typically measured using a UV-visible spectrophotometer, and the Y value obtained after performing a sensitivity correction. Typically, the above degree of polarization can be obtained from the following formula based on the parallel transmittance Tp and the cross transmittance Tc obtained by measuring with an ultraviolet-visible spectrophotometer and correcting the light sensitivity. Degree of polarization (%)={(Tp－Tc)/(Tp+Tc)} ^1/2 ×100

The polarizer can be manufactured by any suitable method. For example, it can be produced by subjecting any appropriate resin film such as polyvinyl alcohol (PVA) resin film to swelling treatment, stretching treatment, dyeing treatment with dichroic substances such as iodine, crosslinking treatment, Various treatments such as washing treatment and drying treatment.

B-2. Protective layer The protective layers 12 and 13 are formed of any appropriate film that can be used as a protective layer of a polarizer. Specific examples of the material constituting the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, and polyamide-based resins. , polyimide series, polyether series series, polysteel series series, polystyrene series series, polynorthylene series series, polyolefin series series, (meth)acrylic series series, acetate series and other transparent resins, etc. In addition, thermosetting resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone, or ultraviolet curable resins can also be mentioned. wait. In addition, glassy polymers, such as a siloxane polymer, are mentioned, for example. Moreover, the polymer film described in Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007) can also be used. As the material of the film, for example, a thermoplastic resin having a substituted or unsubstituted imide group in the side chain, and a thermoplastic resin having a substituted or unsubstituted phenyl and nitrile group in the side chain can be used. The resin composition includes, for example, a resin composition having an alternating copolymer containing isobutylene and N-methylmaleimide, and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extruded product of the aforementioned resin composition.

The polarizing plate with a retardation layer is typically arranged on the viewing side of the image display device, and the protective layer 12 is typically arranged on the viewing side. Therefore, surface treatments such as hard coating treatment, anti-reflection treatment, anti-sticking treatment, and anti-glare treatment can also be applied to the protective layer 12 as required.

The thickness of the protective layer is preferably from 10 μm to 50 μm, more preferably from 10 μm to 30 μm. Furthermore, when surface treatment is applied, the thickness of the outer protective layer (protective layer 12) is the thickness including the thickness of the surface treatment layer.

C. The first retardation layer The first retardation layer 20 is an alignment solidified layer of a liquid crystal compound. By using a liquid crystal compound, it is possible to realize an in-plane retardation equivalent to that of a resin film with a thickness far thinner than that of a resin film. Also, if it is a liquid crystal alignment solidified layer, the phase difference change caused by the dimensional shrinkage of the polarizing plate with a phase difference layer in a high temperature environment may become more significant. In an embodiment of the present invention, even if a retardation layer is used as an alignment-cured layer of a liquid crystal compound, a polarizing plate with a retardation layer excellent in high-temperature durability can be provided. The first retardation layer may be a single layer or a laminate of two or more layers. Typically, the first retardation layer is provided for imparting antireflection characteristics to a polarizing plate.

C-1. The first retardation layer as a single layer When the first retardation layer 20 is a single layer, the single first retardation layer can function as a λ/4 plate. The in-plane retardation Re(550) of the first retardation layer is preferably more than 100 nm and less than 160 nm, more preferably 110 nm to 155 nm, further preferably 130 nm to less than 150 nm.

The Nz coefficient of the first retardation layer as a single layer is preferably from 0.9 to 1.5, more preferably from 0.9 to 1.3. By satisfying such a relationship, when the obtained polarizing plate with a retardation layer is used for an image display device, a very excellent reflection hue can be achieved.

The thickness of the first retardation layer is preferably from 0.5 μm to 10 μm, more preferably from 0.5 μm to 7 μm, and still more preferably from 1 μm to 5 μm.

The first retardation layer preferably exhibits reverse wavelength dispersion characteristics. In this case, Re(550)/Re(650) is preferably more than 1, more preferably more than 1 and 1.2 or less, and still more preferably 1.01 to 1.15. Also, Re(450)/Re(550) of the first retardation layer is preferably less than 1, more preferably less than 0.95, still more preferably less than 0.90. Re(450)/Re(550) is, for example, 0.8 or more. With such a configuration, very excellent antireflection characteristics can be realized.

The angle formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizing element 11 is preferably 40°-50°, more preferably 42°-48°, and even more preferably about 45°. If the angle is within such a range, by using the retardation layer as a λ/4 plate as described above, polarized light with a retardation layer having very excellent circular polarization characteristics (resulting in very excellent antireflection characteristics) can be obtained plate.

As mentioned above, the first retardation layer 20 is an alignment solidified layer of liquid crystal compound. By using the liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be made much larger than that of the non-liquid crystal material, so the thickness of the retardation layer for obtaining the desired in-plane retardation can be made extremely small. As a result, further thinning of the polarizing plate with a retardation layer can be achieved.

The retardation layer, which is an alignment-cured layer of a liquid crystal compound, can be formed using a composition containing a polymerizable liquid crystal compound. In this specification, the polymeric liquid crystal compound contained in a composition means the compound which has a polymeric group and has liquid crystallinity. The polymerizable group means a group participating in a polymerization reaction, preferably a photopolymerizable group. Here, the photopolymerizable group means a group capable of participating in a polymerization reaction due to an active radical or an acid generated by a photopolymerization initiator.

Liquid crystallinity can be thermotropic or lyotropic. Moreover, as a structure of a liquid crystal phase, it may be a nematic liquid crystal or a smectic liquid crystal. From the viewpoint of ease of manufacture, the liquid crystallinity is preferably a thermotropic nematic liquid crystal.

In one embodiment, the retardation layer as a single layer is formed using a composition containing a liquid crystal compound represented by the following formula (1). L ¹ -SP ¹ -A ¹ -D ³ -G ¹ -D ¹ -Ar-D ² -G ² -D ⁴ -A ² -SP ² -L ² (1)

L ¹ and L ² each independently represent a monovalent organic group, and at least one of L ¹ and L ² represents a polymerizable group. The monovalent organic group includes any suitable group. The polymerizable group represented by at least one of L ¹ and L ² may, for example, be a radical polymerizable group (radical polymerizable group). Any appropriate radical polymerizable group can be used as the radical polymerizable group. Acryl or methacryl is preferred. The acryl group is preferred from the standpoint of a faster polymerization rate and improved productivity. The methacryl group can also be used as a polymerizable group of high birefringence liquid crystals in the same way.

SP ¹ and SP ² each independently represent a single bond, a linear or branched alkylene group, or -CH ₂ - constituting a linear or branched alkylene group having 1 to 14 carbons More than one divalent linking group substituted by -O-. The linear or branched alkylene group having 1 to 14 carbon atoms preferably includes methylene, ethylylene, propylylene, butyl, pentylene and hexylene.

^A1 and ^A2 each independently represent an alicyclic hydrocarbon group or an aromatic ring substituent. A ¹ and A ² are preferably an aromatic ring substituent having 6 or more carbon atoms or a cycloalkylene ring having 6 or more carbon atoms.

D ¹ , D ² , D ³ and D ⁴ each independently represent a single bond or a divalent linking group. Specifically, D ¹ , D ² , D ³ and D ⁴ represent single bonds, -O-CO-, -C(=S)O-, -CR ¹ R ² -, -CR ¹ R ² -CR ³ R ⁴ -, -O-CR ¹ R ² -, -CR ¹ R ² -O-CR ³ R ⁴ -, -CO-O-CR ¹ R ² -, -O-CO-CR ¹ R ² -, -CR ¹ R ² -O-CO-CR ³ R ⁴ -, -CR ¹ R ² -CO-O-CR ³ R ⁴ -, -NR ¹ -CR ² R ³ -, or -CO-NR ¹ -. However, at least one of D ¹ , D ² , D ³ and D ⁴ represents -O-CO-. Among them, preferably ^D3 is -O-CO-, more preferably ^D3 and ^D4 are -O-CO-. D ¹ and D ² are preferably single bonds. R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 4 carbon atoms.

G ¹ and G ² each independently represent a single bond or an alicyclic hydrocarbon group. Specifically, G ¹ and G ² may represent unsubstituted or substituted divalent alicyclic hydrocarbon groups with 5-8 carbon atoms. Also, one or more -CH ₂ - constituting the alicyclic hydrocarbon group may be substituted by -O-, -S- or -NH-. G ¹ and G ² preferably represent a single bond.

Ar represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Ar represents, for example, an aromatic ring selected from the group consisting of groups represented by the following formulas (Ar-1) to (Ar-6). Furthermore, in the following formulas (Ar-1) to (Ar-6), *1 represents the bonding position with ^D1 , and *2 represents the bonding position with ^D2 . [chemical 1]

In formula (Ar-1), Q ¹ represents N or CH, and Q ² represents -S-, -O-, or -N(R ⁵ )-. R ⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbons.

In the formulas (Ar-1) to (Ar-6), Z ¹ , Z ² and Z ³ each independently represent a hydrogen atom, a monovalent aliphatic hydrocarbon group with 1 to 20 carbons, and a monovalent lipid with 3 to 20 carbons. A cyclic hydrocarbon group, a valent aromatic hydrocarbon group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -NR ⁶ R ⁷ , or -SR ⁸ . R ⁶ to R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbons, and Z ¹ and Z ² may be bonded to each other to form a ring. The ring may be any of an alicyclic ring, a heterocyclic ring, and an aromatic ring, and is preferably an aromatic ring. The formed ring may be substituted with a substituent.

In formulas (Ar-2) and (Ar-3), A ³ and A ⁴ are independently selected from the group consisting of -O-, -N(R ⁹ )-, -S-, and -CO- The base, R ⁹ represents a hydrogen atom or a substituent. The substituent represented by R ⁹ may, for example, be the same as the substituent that Y ¹ in the above formula (Ar-1) may have.

In formula (Ar-2), X represents a hydrogen atom, or an unsubstituted or substituted group 14 to 16 nonmetal atom. Examples of the nonmetallic atom of Groups 14 to 16 represented by X include an oxygen atom, a sulfur atom, an unsubstituted or substituted nitrogen atom, and an unsubstituted or substituted carbon atom. The substituent may, for example, be the same as the substituent that Y ¹ in the above formula (Ar-1) may have.

In formula (Ar-3), D ⁵ and D ⁶ each independently represent a single bond, -O-CO-, -C(=S)O-, -CR ¹ R ² -, -CR ¹ R ² -CR ³ R ⁴ -, -O-CR ¹ R ² -, -CR ¹ R ² -O-CR ³ R ⁴ -, -CO-O-CR ¹ R ² -, -O-CO-CR ¹ R ² -, - CR ¹ R ² -O-CO-CR ³ R ⁴ -, -CR ¹ R ² -CO-O-CR ³ R ⁴ -, -NR ¹ -CR ² R ³ -, or -CO-NR ¹ -. R ¹ , R ² , R ³ and R ⁴ are as described above.

In the formula (Ar-3), SP ³ and SP ⁴ each independently represent a single bond, a linear or branched alkylene group having 1 to 12 carbons, or a linear or branched chain having 1 to 12 carbons. A divalent linking group in which one or more -CH ₂ - of a branched chain alkylene is substituted by -O-, -S-, -NH-, -N(Q)-, or -CO-, Q represents polymerization sex base.

In formula (Ar-3), L ³ and L ⁴ each independently represent a monovalent organic group, and at least one of L ³ and L ⁴ and L ¹ and L ² in the above formula (1) represents a polymerizable group.

In the formulas (Ar-4) to (Ar-6), Ax represents an organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. In the formulas (Ar-4) to (Ar-6), Ax preferably has an aromatic heterocycle, more preferably has a benzothiazole ring. In the formulas (Ar-4) to (Ar-6), Ay represents a hydrogen atom, an unsubstituted or optionally substituent C1-6 alkyl group, or an alkyl group selected from an aromatic hydrocarbon ring and an aromatic heterocyclic ring An organic group having 2 to 30 carbon atoms in at least one aromatic ring in the group formed. In the formulas (Ar-4) to (Ar-6), Ay preferably represents a hydrogen atom.

In the formulas (Ar-4) to (Ar-6), Q ³ represents a hydrogen atom, or an unsubstituted or optionally substituted alkyl group having 1 to 6 carbon atoms. In the formulas (Ar-4) to (Ar-6), Q ³ preferably represents a hydrogen atom.

Among such Ar, preferably, a group (atomic group) represented by the above-mentioned formula (Ar-4) or the above-mentioned formula (Ar-6) is mentioned.

Specific examples of the liquid crystal compound represented by formula (1) are disclosed in International Publication No. 2018/123551. The description of this publication is incorporated by reference in this specification. These compounds may be used alone or in combination of two or more.

The composition containing a liquid crystal compound preferably contains a polymerization initiator. As the polymerization initiator, any appropriate polymerization agent is used. Preferably, it is a photopolymerization initiator capable of initiating a polymerization reaction by irradiating ultraviolet rays. As a photopolymerization initiator, for example, an α-carbonyl compound (described in the specifications of US Patent No. 2367661 and US Patent No. 2367670), alcohol ketone ether (described in the specification of US Patent No. 2448828), α-hydrocarbon substituted aromatic alcohol and ketone compound (described in US Patent No. 2722512 specification), polynuclear quinone compound (described in US Patent No. 3046127, US Patent No. 2951758 specification), triaryl imidazole dimer and A combination of p-aminophenyl ketone (described in US Patent No. 3549367), a oxadiazole compound (described in US Patent No. 4212970), and an acylphosphine oxide compound (described in Japanese Patent Publication No. 63 -40799 communique, Japanese Patent Application Publication No. 5-29234, Japanese Patent Application Publication No. 10-95788, Japanese Patent Application Publication No. 10-29997). The descriptions of these publications are incorporated herein by reference. The polymerization initiator may be used alone or in combination of two or more.

It is preferable that the composition containing a liquid crystal compound contains a solvent from the viewpoint of the workability of forming a retardation layer. As the solvent, any appropriate solvent can be used, and an organic solvent is preferably used.

The composition containing the liquid crystal compound further includes any appropriate other components. Examples thereof include antioxidants such as phenolic antioxidants, liquid crystal compounds other than the above, leveling agents, surfactants, tilt angle control agents, alignment aids, plasticizers, and crosslinking agents.

The liquid crystal alignment solidified layer can be formed by applying alignment treatment to the surface of a specific substrate, applying a composition (coating solution) containing a liquid crystal compound on the surface, and making the liquid crystal compound react with the above-mentioned The alignment process aligns in the corresponding direction, and fixes the alignment state. In one embodiment, the substrate is any appropriate resin film, and the liquid crystal alignment solidified layer formed on the substrate can be transferred to the surface of the polarizer.

Any appropriate alignment treatment can be adopted as the above-mentioned alignment treatment. Specifically, mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment may 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. The processing conditions of various alignment processing can adopt arbitrary appropriate conditions according to the purpose.

Alignment of the liquid crystal compound is carried out by treating it at a temperature at which a liquid crystal phase is displayed according to the type of the liquid crystal compound. By performing such temperature treatment, the liquid crystal compound is in a liquid crystal state, and the liquid crystal compound is aligned according to the direction of the alignment treatment on the surface of the substrate.

In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned in the above manner. In the case where the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the alignment state is fixed by subjecting the liquid crystal compound aligned in the above manner to a polymerization treatment or a crosslinking treatment.

The details of the formation method of the alignment solidified layer are described in Japanese Patent Laid-Open No. 2006-163343. The description of this publication is incorporated by reference in this specification.

C-2. The first retardation layer with a laminated structure In one embodiment, the first retardation layer has a laminated structure of an alignment solidified layer A of liquid crystal compounds and an alignment solidified layer B of liquid crystal compounds. When the first retardation layer has a laminated structure, either one of the liquid crystal alignment solidified layer A and the liquid crystal alignment solidified layer B can function as a λ/4 plate, and the other can function as a λ/2 plate. For example, when the liquid crystal alignment solidified layer A functions as a λ/2 plate and the liquid crystal alignment solidified layer B functions as a λ/4 plate, the Re(550) of the liquid crystal alignment solidified layer A is preferably 200 nm to 300 nm , more preferably 200 nm to 270 nm, further preferably 210 nm to 260 nm, particularly preferably 230 nm to 260 nm. The Re(550) of the liquid crystal alignment solidified layer B is preferably 100 nm to 200 nm, more preferably 100 nm to 170 nm, further preferably 110 nm to 150 nm, particularly preferably 110 nm to 130 nm.

The thickness of the layer A can be adjusted, for example, to obtain the in-plane retardation required for the λ/2 plate. The thickness of the layer A is, for example, 2.0 μm˜4.0 μm. The thickness of the layer B can be adjusted, for example, to obtain the in-plane retardation required for the λ/4 plate. The thickness of the B layer is, for example, 0.5 μm˜2.5 μm. In this embodiment, the angle formed by the slow axis of layer A and the absorption axis of the polarizer is preferably 10°-20°, more preferably 12°-18°, and even more preferably 12°-16°. Also, the angle formed by the slow axis of the B layer and the absorption axis of the polarizer is preferably 70°-80°, more preferably 72°-78°, further preferably 72°-76°. When the first retardation layer has a laminated structure, each layer (such as A layer and B layer) can show the reverse wavelength dispersion characteristic that the retardation value becomes larger with the wavelength of the measurement light, and can also show the retardation value Positive wavelength dispersion characteristics that become smaller with the wavelength of the measurement light can also show flat wavelength dispersion characteristics in which the retardation value hardly changes regardless of the wavelength of the measurement light.

The retardation layer (at least one layer in the case of having a laminated structure) typically exhibits a relationship of nx>ny=nz in refractive index characteristics. Furthermore, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, ny>nz or ny<nz may exist in the range which does not impair the effect of this invention. The Nz coefficient of the retardation layer is preferably from 0.9 to 1.5, more preferably from 0.9 to 1.3.

In this embodiment, as the said liquid crystal compound used for a 1st retardation layer, the liquid crystal compound (nematic liquid crystal) whose liquid crystal phase is a nematic phase is mentioned, for example. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The expression mechanism of the liquid crystallinity of the 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. The reason for this is that the alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (ie, hardening) the liquid crystal monomer. After aligning the liquid crystal monomers, for example, if the liquid crystal monomers are polymerized or cross-linked, the above-mentioned alignment state can be fixed. Here, although a polymer is formed by polymerization and a three-dimensional network structure is formed by crosslinking, these are non-liquid crystalline. Therefore, the formed retardation layer does not undergo a transition to a liquid crystal phase, a glass phase, or a crystalline phase due to, for example, a temperature change peculiar to a liquid crystal compound. As a result, the retardation layer becomes a retardation layer extremely excellent in stability 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 from 40°C to 120°C, more preferably from 50°C to 100°C, and still more preferably from 60°C to 90°C.

Any appropriate liquid crystal monomer can be used as the liquid crystal monomer. For example, polymerizable mesogens described in Japanese Patent Application Laid-Open No. 2002-533742 (WO00/37585), EP358208 (US5211877), EP66137 (US4388453), WO93/22397, EP0261712, DE19504224, DE4408171, and GB2280445 can be used. base compound wait. Specific examples of such polymerizable mesogen compounds include, for example, a product named LC242 from BASF, a product named E7 from Merck, and a product named LC-Sillicon-CC3767 from Wacker-Chem. . As the liquid crystal monomer, a nematic liquid crystal monomer is preferable. The details of the specific examples of the liquid crystal compound and the formation method of the alignment solidified layer are as described above.

Although the case where the liquid crystal alignment solidified layer A functions as a λ/2 plate and the liquid crystal alignment solidified layer B functions as a λ/4 plate has been described, it is also possible to use the liquid crystal alignment solidified layer A as a λ/4 plate and the liquid crystal alignment solidified layer A to function as a λ/4 plate. The alignment solidified layer B serves as a λ/2 plate. Also, the angle formed by the slow axis of the liquid crystal alignment solidified layer A and the absorption axis of the polarizer can be set to about 75°, and the angle formed by the slow axis of the liquid crystal alignment solidified layer B and the absorption axis of the polarizer can be set to about 75°. 15°.

D. The second retardation layer The second retardation layer 30 is preferably composed of a resin film containing a polymer showing negative birefringence. Here, "showing negative birefringence" means that when a polymer is aligned by stretching or the like, the refractive index in the stretching direction becomes relatively small. In other words, it means that the refractive index in the direction perpendicular to the extending direction becomes larger. Since it is composed of a resin film containing a polymer exhibiting negative birefringence, it is possible to reduce a change in phase difference of the second phase difference layer due to dimensional shrinkage of the polarizing plate. Therefore, the retardation change of the polarizing plate with a retardation layer under a high-temperature environment can be suppressed, and in-plane reflection color unevenness can be suppressed.

The second retardation layer is preferably a so-called positive C plate whose refractive index characteristic exhibits the relationship of nz>nx=ny. By using the positive C plate as the second retardation layer, oblique reflection can be well prevented, and the wide viewing angle of the antireflection function can be realized. The retardation Rth(550) in the thickness direction of the second retardation layer is preferably -10 nm to -200 nm, more preferably -20 nm to -180 nm, further preferably -30 nm to -160 nm, especially The best range is -40 nm to -140 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 the second retardation layer may be less than 10 nm.

The thickness of the second retardation layer 30 can be set to any appropriate thickness. The thickness of the second retardation layer is preferably from 1 μm to 30 μm, more preferably from 2 μm to 20 μm, and still more preferably from 3 μm to 8 μm.

As a polymer showing negative birefringence, for example, a polymer having a chemical bond or a functional group having large polarization anisotropy such as an aromatic ring and/or a carbonyl group introduced into a side chain may be mentioned. Specifically, acrylic resin, styrene resin, maleimide resin, etc. are mentioned. Preferably, at least one polymer selected from the group consisting of acrylic resins, styrene resins, and maleimide resins can be used, and more preferably, styrene resins can be used. The polymer showing negative birefringence may be used alone or in combination of two or more.

An acrylic resin can be obtained by addition-polymerizing an acrylate monomer, for example. As an acrylic resin, polymethyl methacrylate (PMMA), polybutyl methacrylate, polycyclohexyl methacrylate, etc. are mentioned, for example.

A styrene-type resin can be obtained by addition-polymerizing a styrene-type monomer, for example. Examples of styrene-based monomers include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene, p-nitrostyrene, and p-aminostyrene , p-carboxystyrene, p-phenylstyrene, 2,5-dichlorostyrene, p-tert-butylstyrene, etc.

The maleimide resin can be obtained, for example, by addition-polymerizing a maleimide monomer. As maleimide-based monomers, for example, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(2- Methylphenyl)maleimide, N-(2-ethylphenyl)maleimide, N-(2-propylphenyl)maleimide, N-(2-isopropyl phenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-dipropylphenyl)maleimide, N- (2,6-diisopropylphenyl)maleimide, N-(2-methyl-6-ethylphenyl)maleimide, N-(2-chlorophenyl)maleimide Imide, N-(2,6-dichlorophenyl)maleimide, N-(2-bromophenyl)maleimide, N-(2,6-dibromophenyl)maleimide Maleimide, N-(2-biphenyl)maleimide, N-(2-cyanophenyl)maleimide, etc. Maleimide-based monomers can be obtained from, for example, Tokyo Chemical Industry Co., Ltd. and the like.

In addition polymerization, the birefringence properties of the obtained resin can also be controlled by substituting side chains after polymerization, performing maleimidization or grafting reactions, and the like.

Polymers exhibiting negative birefringence may also be copolymerized with other monomers. By copolymerizing other monomers, brittleness, moldability, and heat resistance can be improved. Examples of the above-mentioned other monomers include ethylene, propylene, 1-butene, 1,3-butadiene, 2-methyl-1-butene, 2-methyl-1-pentene, 1- Olefins such as hexene; acrylonitrile; (meth)acrylates such as methyl acrylate and methyl methacrylate; maleic anhydride; vinyl esters such as vinyl acetate, etc.

When the polymer exhibiting negative birefringence is a copolymer of the above-mentioned styrene-based monomer and the above-mentioned other monomer, the compounding ratio of the styrene-based monomer is preferably 50 mol % to 80 mol %. When the above-mentioned polymer showing negative birefringence is a copolymer of the above-mentioned maleimide-based monomer and the above-mentioned other monomers, the blending ratio of the maleimide-based monomer is preferably 2 mol % to 50 mole %. By blending in such a range, a polymer film excellent in toughness and formability can be obtained.

As the above-mentioned polymer exhibiting negative birefringence, styrene-maleic anhydride copolymer, styrene-acrylonitrile copolymer, styrene-(meth)acrylate copolymer, styrene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, Imide copolymer, vinyl ester-maleimide copolymer, olefin-maleimide copolymer, etc. These can be used individually or in combination of 2 or more types. These polymers can exhibit high negative birefringence and are excellent in heat resistance. These polymers can be obtained from, for example, NOVA Chemical Japan, Arakawa Chemical Industry Co., Ltd., and the like.

As the above-mentioned polymer showing negative birefringence, a polymer having a repeating unit represented by the following general formula (II) can also be preferably used. Such polymers can exhibit higher negative birefringence, and are excellent in heat resistance and mechanical strength. Such a polymer can be obtained, for example, by using an N-phenyl-substituted maleimide having a phenyl group having a substituent at least in the ortho position introduced as an initiator. The N substituent of the maleimide-based monomer as the starting material. [Chem 2]

In the above general formula (II), R ₁ to R ₅ independently represent a hydrogen atom, a halogen atom, a carboxylic acid, a carboxylate, a hydroxyl group, a nitro group, or a linear or branched alkyl group having 1 to 8 carbon atoms or an alkoxy group (wherein, R ₁ and R ₅ are not hydrogen atoms at the same time), R ₆ and R ₇ represent a hydrogen atom, or a straight-chain or branched alkyl or alkoxy group with 1 to 8 carbons, and n represents An integer of 2 or more.

The polymer exhibiting negative birefringence is not limited to the above, and for example, a cyclic olefin-based copolymer disclosed in JP-A-2005-350544 and the like can also be used. Furthermore, compositions containing polymers and inorganic microparticles as disclosed in JP-A-2005-156862 and JP-A-2005-227427 are also suitably used. Furthermore, it can also be used after being modified by copolymerization, branching, crosslinking, molecular terminal modification (or sealing), stereoregular modification, and the like.

The resin composition for forming the second retardation layer may further contain any appropriate additives if necessary. Specific examples of additives include plasticizers, heat stabilizers, light stabilizers, lubricants, antioxidants, ultraviolet absorbers, flame retardants, colorants, antistatic agents, compatibilizers, and crosslinking agents , Tackifier, etc. The type and content of additives can be appropriately set depending on the purpose. Typically, the content of the additive is about 3 to 10 parts by weight with respect to 100 parts by weight of the total solid content of the resin composition. If the content of the additive is too high, the transparency of the polymer film may be impaired, or the additive may ooze out from the surface of the polymer film.

Any appropriate forming method can be adopted as the forming method of the second retardation layer. For example, compression molding method, transfer molding method, injection molding method, extrusion molding method, blow molding method, powder molding method, FRP (Fiber Reinforced Plastics, fiber reinforced plastics) molding method, solvent casting method, etc. may be mentioned. Among them, the extrusion molding method and the solvent casting method can be preferably used. The reason for this is that a retardation film with high smoothness and good optical uniformity can be obtained. Specifically, the extrusion molding method is a method in which a resin composition containing the above-mentioned thermoplastic resin, plasticizer, additives, etc. is heated to melt, and then extruded into a film form using a T-die or the like until it is cast. The surface of the roll is then cooled to form a film. The solvent casting method is a method as follows: After defoaming the thick solution (film-making solution) obtained by dissolving the above resin composition in a solvent, it is evenly cast in the form of a thin film on a metal ring or On the surface of the drum or plastic substrate, the solvent is evaporated to form a film. In addition, molding conditions can be suitably set according to the composition and kind of resin to be used, a molding processing method, etc.

E. Adhesive layer Any appropriate adhesive can be used as the adhesive constituting the adhesive layer (adhesive layer between the image display device) provided as the outermost layer. Examples of adhesives include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinyl alcohol-based adhesives, Vinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, and the like. Among these adhesives, those that are excellent in optical transparency, exhibit appropriate wettability, cohesiveness, and adhesive properties, and are excellent in weather resistance or heat resistance can be preferably used. As an adhesive exhibiting such characteristics, an acrylic adhesive can be preferably used.

F. Image display device The polarizing plate with a retardation layer described in the above items A to E can be applied to an image display device. Therefore, an embodiment of the present invention includes an image display device using such a polarizing plate with a retardation layer. Representative examples of image display devices include liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL 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 E on the viewing side. The polarizing plate with retardation layer is laminated in such a way that the retardation layer is on the side of the image display unit (eg liquid crystal cell, organic EL unit, inorganic EL unit) (the polarizer is on the viewing side). Example

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited by these examples. The measurement method of each characteristic is as follows. In addition, unless otherwise stated, "part" and "%" in an Example and a comparative example are a basis of weight.

(1) Thickness The thickness of 10 μm or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000"). The thickness exceeding 10 μm was measured using a digital micrometer (manufactured by Anlizhi Co., Ltd., product name "KC-351C").

(2) Uneven reflection hue The polarizing plates with retardation layers obtained in Examples and Comparative Examples were cut into samples of 60 mm in length and 130 mm in width. The portion of the sample that is 30 mm in length and 25 mm in width is defined as measurement position A, the portion of 30 mm in length and 65 mm in width is defined as measurement position B, and the portion of 30 mm in length and 105 mm in width is defined as measurement position C . Then, the adhesive layer of the polarizing plate with retardation layer was pasted and laminated on a glass plate (80 mm×150 mm) with a thickness of 0.5 mm. Thereafter, the polarizing plate with a retardation layer attached to the glass plate was left to stand at 80° C. for 500 hours. Using a spectrophotometer (manufactured by Konica Minolta, product name: CM-26d), the hue a* value and hue b* value at measurement positions A, B, and C were measured, respectively. Plot the hue a* value and hue b* value of each measurement position, compare the results of measurement position A and measurement position B, and the results of measurement position B and measurement position C, and compare the hue difference (between the plots) The value of the one with the larger distance) is used as the hue unevenness of each sample.

(3) Phase difference change The polarizing plates with retardation layers obtained in Examples and Comparative Examples were cut into samples with a width of 15 mm and a length of 200 mm. Using a tensiometer (manufactured by MyCarbon Corporation, product name: Digital Luggage Scale), tension was applied to the longitudinal direction of the obtained sample. The in-plane phase difference was measured using a phase difference measuring device (manufactured by Oji Scientific Instruments Co., Ltd., product name: KOBRA-WPR) at stages of tension of 0 kg, 0.5 kg, 1 kg, 1.5 kg, and 2 kg. Plot the phase difference measured under each tension, calculate the slope, and use it as the value of the phase difference change.

[Manufacturing example 1: Production of polarizing plate] 1. Fabrication of polarizing elements For a long roll of polyvinyl alcohol (PVA)-based resin film (manufactured by Kuraray, product name "PE3000") with a thickness of 30 μm, use a roll stretcher so that it becomes 5.9 times longer in the longitudinal direction. Uniaxial stretching is carried out on the upper side, swelling, dyeing, cross-linking, washing are applied to one side at the same time, and finally drying is applied to produce a polarizing element with a thickness of 12 μm. Specifically, the swelling treatment was extended to 2.2 times while being treated in pure water at 20°C. Next, the dyeing treatment was carried out in an aqueous solution at 30°C whose iodine concentration was adjusted to a weight ratio of iodine to potassium iodide of 1:7 so that the single transmittance of the obtained polarizing element became 45.0%. 1.4 times. Furthermore, the cross-linking treatment adopts a two-stage cross-linking treatment. The first-stage cross-linking treatment is carried out in an aqueous solution at 40°C dissolved in boric acid and potassium iodide, and is extended to 1.2 times while being treated. The content of boric acid in the aqueous solution of the crosslinking treatment in the first stage was 5.0% by weight, and the content of potassium iodide was 3.0% by weight. The second stage of cross-linking treatment is in a 65°C aqueous solution dissolved with boric acid and potassium iodide, and the cross-linking treatment is performed while extending to 1.6 times. The content of boric acid in the aqueous solution of the cross-linking treatment in the second stage was 3.7% by weight, and the content of potassium iodide was set at 5.0% by weight. In addition, the cleaning treatment was performed in a potassium iodide aqueous solution at 20°C. The potassium iodide content of the aqueous solution of washing|cleaning process was 3.1 weight%. Finally, the drying treatment is performed at 70° C. for 5 minutes to obtain a polarizing element.

2. Production of polarizing plate On the surface of the polarizing element obtained above (the surface opposite to the resin substrate), an HC-COP film was bonded as a protective layer via an ultraviolet curing adhesive. Specifically, it was applied so that the total thickness of the curable adhesive became 1.0 μm, and bonded using a roller press. Thereafter, UV (Ultraviolet) rays are irradiated from the protective layer side to harden the adhesive. Furthermore, the HC-COP film is a film with a hard coat (HC) layer (thickness 2 μm) formed on a cycloolefin (COP) film (manufactured by Japan Zeon Corporation, product name "ZF12", thickness 25 μm), and The COP film is bonded so that it becomes the polarizer side. Then, the resin substrate was peeled off to obtain a polarizing plate having a protective layer (HC layer/COP film)/adhesive layer/polarizing element.

[Manufacturing Example 2: Preparation of the first retardation layer A (single first retardation layer)] 55 parts by weight of the compound represented by the following formula (I), 25 parts by weight of the compound represented by the following formula (II) 20 parts by weight and 20 parts by weight of the compound represented by formula (III) were added to 400 parts by weight of cyclopentanone (CPN), and then heated to 60° C. and stirred to dissolve. Thereafter, the solution of the above-mentioned compound was returned to room temperature, and 3 parts by weight of Irgacure 907 (manufactured by BASF Japan), 0.2 parts by weight of MEGAFAC F-554 (manufactured by DIC Corporation), and p-methoxyl were added to the solution of the above-mentioned compound. 0.1 parts by weight of phenol (MEHQ) was further stirred. The solution after stirring was transparent and uniform. The obtained solution was filtered with a 0.20 μm membrane filter to obtain a polymerizable composition. In addition, using a spin coating method, polyimide for an alignment film is solution-coated on a glass substrate with a thickness of 0.7 mm, dried at 100°C for 10 minutes, and then baked at 200°C for 60 minutes. Get a coating. The obtained coating film was rubbed with a commercially available rubbing device to form an alignment film. Next, the polymerizable composition obtained above was coated on a substrate (substantially an alignment film) by a spin coating method, and dried at 100° C. for 2 minutes. After the obtained coating film was cooled to room temperature, it was irradiated with ultraviolet light at an intensity of 30 mW/ ^cm2 for 30 seconds using a high-pressure mercury lamp to obtain a first retardation layer (thickness 3 μm) as an alignment solidified layer of a liquid crystal compound. ). The in-plane retardation Re(550) of the first retardation layer was 130 nm. Also, Re(450)/Re(550) of the first retardation layer was 0.851, showing reverse wavelength dispersion characteristics. The first retardation layer can function as a λ/4 plate. [Chem 3] [chemical 4]

[Manufacturing Example 3: Fabrication of the Second Retardation Layer] In an autoclave equipped with a stirrer, a condenser tube, a nitrogen inlet tube, and a thermometer, 48 parts by weight of hydroxypropyl methylcellulose (manufactured by Shin-Etsu Chemical, trade name: Metolose 60SH-50), 15601 parts by weight of distilled water, and transbutene were added. 8161 parts by weight of diisopropyl diacid, 240 parts by weight of 3-ethyl-3-oxetanylmethyl acrylate, and 45 parts by weight of tert-butyl peroxypivalate as a polymerization initiator, for 1 hour After blowing nitrogen gas, the mixture was kept at 49° C. for 24 hours while stirring, thereby performing radical suspension polymerization. Then, after cooling to room temperature, the resulting suspension containing polymer particles was centrifuged. The obtained polymer was washed twice with distilled water and washed twice with methanol, and then dried under reduced pressure. The obtained fumarate resin was dissolved in a toluene-methyl ethyl ketone mixed solution (toluene/methyl ethyl ketone 50% by weight/50% by weight) to prepare a 20% solution. Furthermore, 5 parts by weight of tributyl trimellitate was added as a plasticizer with respect to 100 parts by weight of the fumarate resin, and a film-forming liquid was prepared. As the support film, a biaxially stretched film (thickness: 75 μm) of polyester (polyethylene terephthalate-polyethylene isophthalate copolymer) was used. On the support film, the prepared film-forming solution was applied so that the film thickness after drying would be 5 μm, and dried at 140° C. The coating film after drying (positive C plate) is Re(550)≒0 nm, Rth(550)=-75 nm.

[Manufacturing Example 4: Production of the first retardation layer B (the first retardation layer having a laminated structure)] A polymerizable liquid crystal displaying a nematic liquid crystal phase (manufactured by BASF: trade name "Paliocolor LC242") was made from the following 10 g of the above formula) and 3 g of a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF: trade name "Irgacure 907") were dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid ). [chemical 5] The surface of a polyethylene terephthalate (PET) film (thickness: 38 μm) was rubbed with a rubbing cloth to perform an alignment treatment. The direction of the alignment treatment is set so that when it is attached to a polarizing plate, the direction relative to the absorption axis of the polarizing element is a 15° direction when viewed from the viewing side. The above-mentioned liquid crystal coating solution was coated on the alignment-treated surface with a bar coater, and heated and dried at 90° C. for 2 minutes, thereby aligning the liquid crystal compound. The thus-formed liquid crystal layer was irradiated with light of 1 mJ/cm ² using a metal halide lamp to harden the liquid crystal layer, whereby a liquid crystal alignment-cured layer A was formed on the PET film. The thickness of the liquid crystal alignment solidified layer A is 2.5 μm, and the in-plane retardation Re(550) is 270 nm. Furthermore, the liquid crystal alignment solidified layer A exhibits a refractive index characteristic of nx>ny=nz.

The liquid crystal alignment solidified layer B was formed on the PET film in the same manner as above except that the coating thickness was changed, and the alignment treatment direction was set at 75° from the viewing side relative to the absorption axis of the polarizer. The thickness of the liquid crystal alignment solidified layer B is 1.5 μm, and the in-plane retardation Re(550) is 140 nm. Furthermore, the liquid crystal alignment solidified layer B exhibits a refractive index characteristic of nx>ny=nz.

[Example 1] The protective layer (triacetyl cellulose (TAC) film, thickness: 20 μm) was bonded to the polarizing element of the polarizing plate obtained in Production Example 1 through an adhesive layer to obtain a protective layer (HC layer/COP film) /Adhesive layer/polarizer/adhesive layer/protective layer (TAC) polarizer. In addition, for the liquid crystal alignment solidified layer A and the liquid crystal alignment solidified layer B obtained in Manufacturing Example 4, the angle formed by the absorption axis of the polarizer and the slow axis of the alignment solid layer A is 15°, and the absorption axis of the polarizer and the slow axis of the alignment solidification layer A are 15°. The slow axis of the alignment solidified layer B forms an angle of 75°, and the transfer (lamination) is performed sequentially. The alignment-cured layer A and the alignment-cured layer B are respectively laminated via ultraviolet curable adhesives (thickness after curing: 1 μm). Next, apply an ultraviolet curable adhesive (thickness after curing: 1 μm) on the liquid crystal alignment solidified layer B, and laminate the second retardation layer obtained in Production Example 3 to obtain liquid crystal alignment solidified layer A/adhesive layer/ Laminate of liquid crystal alignment solidified layer B/adhesive layer/second retardation layer. Next, the TAC-side surface of the obtained polarizing plate was laminated with the liquid crystal alignment solidified layer A of the above-mentioned laminate through an acrylic adhesive layer (thickness: 5 μm). Then, the base material of the second retardation layer was peeled off. Thereafter, an acrylic adhesive (thickness: 26 μm) was applied on the substrate peeling surface of the second retardation layer to obtain a protective layer (HC layer/COP film)/adhesive layer/polarizer/adhesive layer/ Adhesive layer (TAC)/adhesive layer/first retardation layer (liquid crystal alignment solidified layer A/adhesive layer/liquid crystal alignment solidified layer B)/adhesive layer/second retardation layer/adhesive layer Polarizer for phase difference layer. The above-mentioned evaluation was performed on the obtained polarizing plate. The results are shown in Table 1.

(comparative example 1) Except not having laminated|stacked the 2nd retardation layer, it carried out similarly to Example 1, and obtained the polarizing plate with a retardation layer. The above-mentioned evaluation was performed on the obtained polarizing plate. The results are shown in Table 1.

[Manufacturing Example 5: Production of a positive C plate as a liquid crystal alignment solidified layer] Make the following chemical formula (numbers 65 and 35 in the formula represent the mole % of the monomer unit, and express it with a block polymer body for convenience: weight 20 parts by weight of a side-chain type liquid crystal polymer represented by an average molecular weight of 5000), 80 parts by weight of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name Paliocolor LC242), and a photopolymerization initiator (Ciba Specialty Chemicals Inc.: Trade name Irgacure 907) 5 parts by weight was dissolved in 200 parts by weight of cyclopentanone to prepare a liquid crystal coating liquid. Then, this coating liquid was applied on the PET substrate subjected to the vertical alignment treatment using a bar coater, and then heated and dried at 80° C. for 4 minutes to align the liquid crystals. The liquid crystal layer was irradiated with ultraviolet rays to harden the liquid crystal layer, thereby forming a retardation layer (thickness 3 μm) exhibiting a refractive index characteristic of nz>nx=ny on the substrate. [chemical 6]

(comparative example 2) Except having used the retardation layer obtained in the manufacture example 5 instead of the 2nd retardation layer obtained in the manufacture example 3, it carried out similarly to Example 1, and obtained the polarizing plate with a retardation layer. The above-mentioned evaluation was performed on the obtained polarizing plate. The results are shown in Table 1.

[Example 2] The protective layer (triacetyl cellulose (TAC) film, thickness: 20 μm) was bonded to the polarizing element of the polarizing plate obtained in Production Example 1 through an adhesive layer to obtain a protective layer (HC layer/COP film) /Adhesive layer/polarizer/adhesive layer/protective layer (TAC) polarizer. In addition, for the first retardation layer A obtained in Production Example 2, the angle formed by the absorption axis of the polarizer and the slow axis of the first retardation layer A was 45° to the protective layer of the above-mentioned polarizing plate ( TAC) for bonding. The first retardation layer and the protective layer (TAC) are laminated through an ultraviolet curable adhesive (thickness after curing: 1 μm). Next, the TAC-side surface of the obtained polarizing plate and the first retardation layer were laminated through an acrylic adhesive layer (thickness: 5 μm). Then, the base material of the second retardation layer was peeled off. Thereafter, an acrylic adhesive (thickness: 26 μm) was applied on the substrate peeling surface of the second retardation layer to obtain a protective layer (HC layer/COP film)/adhesive layer/polarizer/adhesive layer/ Protective layer (TAC)/adhesive layer/first retardation layer/adhesive layer/second retardation layer/adhesive layer is a polarizing plate with a retardation layer. The above-mentioned evaluation was performed on the obtained polarizing plate. The results are shown in Table 1.

(comparative example 3) Except not having laminated|stacked the 2nd retardation layer, it carried out similarly to Example 2, and obtained the polarizing plate with a retardation layer. The above-mentioned evaluation was performed on the obtained polarizing plate. The results are shown in Table 1.

(comparative example 4) Except having used the retardation layer obtained in the manufacture example 5 instead of the 2nd retardation layer obtained in the manufacture example 3, it carried out similarly to Example 1, and obtained the polarizing plate with a retardation layer. The above-mentioned evaluation was performed on the obtained polarizing plate. The results are shown in Table 1.

[Table 1] Composition of the first retardation layer Composition of the second retardation layer Phase difference change (slope) Uneven reflection Example 1 Laminated structure of two layers resin 0.8 0.3 Comparative example 1 none 1.6 0.62 Comparative example 2 liquid crystal 2.1 0.81 Example 2 single layer resin 1.7 0.7 Comparative example 3 none 2.7 0.91 Comparative example 4 liquid crystal 3.2 1.11

[evaluate] As can be seen from Table 1, the polarizing plate with a retardation layer according to the examples of the present invention has excellent high-temperature durability, and the in-plane unevenness of reflection hue is suppressed. [Industrial availability]

The polarizing plate with retardation layer of the present invention is suitable for image display devices such as liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

10: polarizer 11: Polarizing element 12: Protective layer 13: Protective layer 20: The first retardation layer 21: Liquid crystal alignment curing layer A 22: Liquid crystal alignment solidified layer B 30: The second retardation layer 100: Polarizing plate with retardation layer 101: Polarizing plate with retardation layer

FIG. 1 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention.

10: polarizer

11: Polarizing element

12: Protective layer

13: Protective layer

20: The first retardation layer

30: The second retardation layer

100: Polarizing plate with retardation layer

Claims (10)

A polarizing plate with a retardation layer, which has: Polarizing plate, which includes a polarizing element with a thickness of 7 μm or more; The first retardation layer is an alignment solidified layer of a liquid crystal compound; and The second retardation layer is composed of a resin film containing a polymer exhibiting negative birefringence. The polarizing plate with a retardation layer according to claim 1, wherein the second retardation layer is adjacent to the first retardation layer. The polarizing plate with retardation layer according to claim 1 or 2, wherein the second retardation layer is a positive C plate. A polarizing plate with a retardation layer according to any one of claims 1 to 3, wherein the thickness of the second retardation layer is 1 μm to 30 μm. A polarizing plate with a phase difference layer according to any one of Claims 1 to 4, wherein the above-mentioned polymer showing negative birefringence is selected from acrylic resins, styrene resins, and maleimide resins. At least one of the group. A polarizing plate with a retardation layer according to any one of claims 1 to 5, wherein the in-plane retardation of the first retardation layer is 100 nm<Re(550)<160 nm, and Re(450)/ Re(550)<1, and Re(650)/Re(550)>1. The polarizing plate with a retardation layer according to claim 6, wherein the angle formed by the slow axis of the first retardation layer and the absorption axis of the polarizing element is 40°-50°. The polarizing plate with a phase difference layer according to any one of claims 1 to 5, wherein the first phase layer has a laminated structure of an alignment solidified layer A of a liquid crystal compound and an alignment solidified layer B of a liquid crystal compound, and The alignment-hardened layer A functions as a λ/2 plate, and the alignment-hardened layer B functions as a λ/4 plate. A polarizing plate with a phase difference layer as claimed in claim 8, wherein the angle formed by the slow axis of the alignment-cured layer A of the above-mentioned liquid crystal compound and the absorption axis of the above-mentioned polarizer is 70° to 80°, and the alignment-cured layer of the above-mentioned liquid crystal compound is The angle formed by the slow axis of layer B and the absorption axis of the polarizer is 10°-20°. An image display device comprising the polarizing plate with a retardation layer according to any one of Claims 1 to 9.