Polarizing plate and method for manufacturing the same

Abstract

To provide a polarization plate having curve surface shape excellent in a lamination property on a surface to be laminated.SOLUTION: A polarization plate includes a curved surface substrate, and optical alignment film, and polarizer in this order, and has curved surface shape. The polarizer is constituted by a hardened material of a polymerizable liquid crystal composition including a polymerizable liquid crystal compound having at least one polymerizable group, and a dichroic dye. The polymerizable liquid crystal compound is oriented such that an absorption axis of the polarizer is directed in one direction relative to a surface direction of a curve surface of the curved surface substrate on which the polarizer is laminated.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polarizing plate having a curved surface shape and a method for manufacturing the polarizing plate.

Background Art

[0002] A polarizing plate composed of a polarizer is used as a member constituting various articles in a wide range of fields such as liquid crystal display devices, organic EL display devices using organic light emitting diodes (OLEDs), sunglasses, and lens filters. Conventionally, as such a polarizing plate, a protective layer such as a triacetyl cellulose film is laminated via an adhesive layer on at least one surface of a polarizer in which a compound exhibiting dichroism such as iodine or a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. A polarizing plate having such a configuration is widely used (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, as the uses of polarizing plates have become diverse, depending on the use, it has been required to provide a polarizing plate on an article having a curved surface shape rather than a planar shape. However, when using a film-like polarizing plate as described in Patent Document 1 when providing a polarizing plate on a curved surface shape, wrinkles and distortion are likely to occur when bonding to the curved surface, which not only causes defects in appearance and optical characteristics, but may also cause a decrease in adhesion to the surface on which the polarizing plate is laminated. The occurrence of wrinkles and distortion when using such a film-like polarizing plate and the problems caused thereby are particularly likely to become prominent when providing a polarizing plate on a three-dimensional curved surface rather than a developable surface.

[0005] An object of the present invention is to provide a polarizing plate having a curved surface shape excellent in lamination property with respect to a laminated surface.

Means for Solving the Problems

[0006] As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention includes the following aspects. [1] A polarizing plate having a curved surface shape, including a curved surface substrate, an optically oriented film, and a polarizer in this order, wherein the polarizer is composed of a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye, and the polymerizable liquid crystal compound is oriented so that the absorption axis of the polarizer is directed in one direction with respect to the surface direction of the curved surface of the curved surface substrate on which the polarizer is laminated. [2] The polarizing plate according to [1], wherein the curved surface shape is a three-dimensional curved surface shape. [3] The polarizing plate according to [1] or [2], wherein the curved surface shape is lens-shaped. [4] Formula (1): 20 mm ≦ R ≦ 300 mm (1) [In formula (1), R represents the radius of curvature of the portion of the polarizing plate having the smallest curvature] The polarizing plate according to any one of [1] to [3], which satisfies the above condition. [5] The polarizing plate according to any one of [1] to [4], wherein the polarizer further contains a leveling agent. [6] The polarizing plate according to any one of [1] to [5], wherein the dichroic dye is an azo dye. [7] The polarizing plate according to any one of [1] to [6], wherein the polarizer exhibits a Bragg peak in X-ray analysis measurement. [8] An elliptical polarizing plate including the polarizing plate according to any one of [1] to [7] and a retardation layer having a quarter-wave plate function. [9] (a) A step of forming an optically oriented film on a curved surface substrate, (b) A step of forming a coating film of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound and a dichroic dye on the optically oriented film, and (c) A step of forming a polarizer by polymerizing a polymerizable liquid crystal compound while maintaining a smectic liquid crystal state after phase-transitioning the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition into a smectic liquid crystal phase comprising A method for manufacturing a polarizing plate having a curved surface shape, wherein the polymerizable liquid crystal compound is aligned so that the absorption axis of the polarizer faces in one direction with respect to the surface direction of the curved surface of the curved substrate on which the polarizer is laminated.

[10] A flexible image display device having the elliptical polarizing plate according to [8] above.

[11] The flexible image display device according to

[10] above, further comprising a window and a touch panel touch sensor.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a polarizing plate having a curved surface shape excellent in lamination properties with respect to the surface to be laminated.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described in detail. It should be noted that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0009] The polarizing plate of the present invention includes a curved substrate, an optical alignment film, and a polarizer in this order. Since the optical alignment film and the polarizer are laminated on the curved substrate, the polarizing plate of the present invention is a polarizing plate having a curved surface shape at least in part.

[0010] In the present invention, the curved surface shape means a shape having a curvature exceeding 0, and includes a curved surface shape that is a developable surface and a three-dimensional curved surface shape. The developable surface means a surface that can be developed into a plane without stretching or contracting each part of the surface. As the curved surface shape, for example, surfaces corresponding to a part or all of a cylindrical circumferential surface, an elliptical cylindrical circumferential surface, a conical circumferential surface, an elliptical conical circumferential surface, etc. can be mentioned, and it may be a convex curved surface or a concave curved surface. The three-dimensional curved surface means a curved surface that cannot be formed by deforming a plane, that is, a curved surface that is not a developable surface. As the three-dimensional curved surface shape, surfaces corresponding to a part or all of a spherical surface, an ellipsoidal surface, etc., and surfaces corresponding to a part or all of a curved surface whose cross section forms a parabola, a hyperbola, etc. can be mentioned, and it may be a convex curved surface or a concave curved surface. Note that the polarizing plate of the present invention only needs to have a curved surface shape at least in a part thereof, and may have a shape combining a planar shape and a curved surface shape, or the entire polarizing plate may have a curved surface shape. Further, the curved surface shape included in the polarizing plate may be composed of only one of a curved surface shape that is a developable surface or a three-dimensional curved surface shape, or may be composed of a combination of a curved surface that is a developable surface and a three-dimensional curved surface, or a combination of a curved surface that is a developable surface and / or a three-dimensional curved surface and a plane.

[0011] The polarizer constituting the polarizing plate of the present invention is composed of a cured product of a polymerizable liquid crystal composition, and it is possible to easily provide a polarizer while maintaining a high alignment order along the curved surface shape even for a three-dimensional curved surface substrate to which it is difficult to bond a film-like polarizer such as a polyvinyl alcohol resin film adsorbed with a dichroic dye that has been widely used as a conventional polarizer. Therefore, when the curved surface shape included in the polarizing plate is a three-dimensional curved surface shape that cannot be obtained by developing a planar film, the effect of the present invention can be more remarkably achieved. Therefore, in one aspect of the present invention, the polarizing plate of the present invention includes a three-dimensional curved surface shape.

[0012] In one aspect of the present invention, it is preferable that the curved surface shape of the polarizing plate is lens-shaped. The lens-shaped curved surface shape means a curved surface shape having a constant curvature in all directions on the curved surface. Examples of the lens-shaped curved surface shape include a spherical surface, an ellipsoidal spherical surface, a hemispherical surface, a semi-ellipsoidal spherical surface, etc., and it may be a convex lens shape or a concave lens shape. The polarizing plate of the present invention can provide a lens-shaped polarizing plate that is excellent in the lamination property of the polarizer with respect to the laminated surface and suppresses the occurrence of wrinkles and distortion in each layer constituting the polarizing plate, and thus is excellent in appearance characteristics and optical characteristics.

[0013] In one aspect of the present invention, it is preferable that the polarizing plate of the present invention satisfies formula (1). 20 mm ≤ R ≤ 300 mm (1) [In formula (1), R represents the radius of curvature of the portion having the smallest curvature in the polarizing plate.] Formula (1) means that the radius of curvature of the gentlest curved surface of the polarizing plate is 20 mm or more and 300 mm or less. Even when the polarizing plate of the present invention has a curved surface shape with a relatively large curvature, it can achieve a high lamination property of the polarizer provided on the curved surface substrate. Therefore, the radius of curvature R of the portion having the smallest curvature in the polarizing plate of the present invention (hereinafter, also simply referred to as "radius of curvature R") may be, for example, 250 mm or less, or 200 mm or less. Further, the radius of curvature R is more preferably 25 mm or more, and even more preferably 30 mm or more. When the radius of curvature R is equal to or greater than the above lower limit value, the lamination property is more likely to be improved.

[0014] In the polarizing plate of the present invention, the radius of curvature R' of the portion having the largest curvature (hereinafter, also simply referred to as "radius of curvature R'") is preferably 10 mm or more, more preferably 15 mm or more, still more preferably 20 mm or more, particularly preferably 25 mm or more, and most preferably 30 mm or more. When the radius of curvature R' is equal to or greater than the above lower limit value, it is easier to further improve the lamination property and adhesion of the polarizer laminated as the cured product layer (coating layer) of the polymerizable liquid crystal composition to the laminated surface, and it is easy to obtain a polarizing plate in which peeling or floating of the polarizer as the cured product layer hardly occurs. Even when the polarizing plate of the present invention has a curved surface shape with a relatively large curvature, since it can achieve high lamination property of the polarizer provided on the curved substrate, the radius of curvature R' may be, for example, 250 mm or less, 200 mm or less, or even 150 mm or less. In addition, when the curved surface shape included in the polarizing plate is a shape having the same curvature in all directions of the curved surface such as a lens-shaped curved surface shape, the radius of curvature R'' is usually equal to or greater than the lower limit value of the radius of curvature R' and equal to or less than the upper limit value of the radius of curvature R.

[0015] The polarizing plate of the present invention is a polarizing plate having a curved surface shape at least in a part thereof, and includes a curved substrate as a substrate for laminating the photo-alignment film and the polarizer. In the present invention, the curved substrate means a substrate having a surface at least a part of which is a curved surface shape, and the entire surface of the substrate may be a curved surface shape. The curved substrate usually has the same curved surface shape as the curved surface shape described above that the polarizing plate of the present invention has.

[0016] The curved substrate is not particularly limited as long as it is made of a material capable of forming a desired curved shape, and may be appropriately selected from known materials according to the desired curved shape, the use of the polarizing plate, etc. For example, a glass substrate, a film substrate, a metal substrate, etc. may be mentioned. From the viewpoint of easily forming various curved shapes, the curved substrate is preferably made of a glass substrate or a film substrate, and more preferably made of a glass substrate or a resin film substrate. Since the polarizing plate of the present invention usually constitutes an article such as a display device, sunglasses, a lens filter, etc. that is required to transmit light without removing the curved substrate, from the viewpoint of optical characteristics, the curved substrate is preferably made of a substrate having light transmittance. In the present invention, the substrate having light transmittance means a substrate having the property of transmitting light, particularly visible light, and the light transmittance means the property that the transmittance with respect to light rays ranging from a wavelength of 380 nm to 780 nm is 80% or more. Also, although it varies depending on the configuration of the polarizing plate, it is usually preferably optically isotropic.

[0017] Examples of the substrate having light transmittance include a glass substrate and a transparent resin film substrate. Examples of the resin constituting the resin film substrate include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid ester; polyacrylic acid ester; cellulose ester; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide; and polyphenylene oxide. From the viewpoint of forming a polarizer, a glass substrate or a material having a hardness similar thereto is suitable as the substrate.

[0018] The member itself having a curved shape that constitutes an article such as a display device incorporating the polarizing plate of the present invention may be used as the curved substrate.

[0019] The surface of the surface substrate may be subjected to surface treatments such as corona treatment and plasma treatment, and release treatments such as silicone treatment. Further, a hard coat treatment, an antireflection treatment, an antistatic treatment, etc. may be performed on the substrate surface on the side where the polarizer is not laminated.

[0020] The thickness of the curved surface substrate may be appropriately determined according to the curved surface shape, the material constituting the curved surface substrate, the use of the polarizing plate, etc. The entire curved surface substrate may have the same thickness or different thicknesses. The thickness of the curved surface substrate is, for example, 30 μm to 5 cm, preferably 100 μm to 3.5 cm, more preferably 500 μm to 3 cm.

[0021] The polarizer constituting the polarizing plate of the present invention is composed of a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye. The polarizer composed of the cured product of the polymerizable liquid crystal composition is, as described later, a coating layer obtained by applying the polymerizable liquid crystal composition on the surface on which the polarizer is formed and polymerizing it in a state where the polymerizable liquid crystal compound is aligned. By forming the polarizer as a coating layer, high lamination properties of the polarizer can be realized for curved surface shapes having various curvatures. When the lamination property is high, a high alignment order of the polarizer is easily maintained, and a polarizing plate with excellent optical properties is easily obtained. In the present invention, "lamination property" refers to a property in which, when forming a layer such as a polarizer on the surface to be laminated, there are no wrinkles, distortions, coating unevenness, etc. in the laminated layer, and floating or peeling from the surface to be laminated hardly occurs.

[0022] In the polarizer, the polymerizable liquid crystal compound is oriented so that the absorption axis of the polarizer is oriented in one direction in the surface direction of the curved surface of the curved surface substrate on which the polarizer is laminated. When the polymerizable liquid crystal compound constituting the polarizer is oriented so that the absorption axis of the polarizer is oriented in one direction, a polarizer with a high degree of alignment order of the polymerizable liquid crystal compound is obtained, and a polarizing plate with excellent optical properties can be obtained. Here, the alignment of the polymerizable liquid crystal compound such that the absorption axis of the polarizer is oriented in one direction means that, in the case of a curved surface that is a developable surface, when the curved surface is developed into a plane, the polymerizable liquid crystal compound is aligned such that the absorption axis of the polarizer is oriented in one direction on the plane. Further, in the case of a three-dimensional curved surface such as a spherical surface, it means that when the curved surface is viewed in a plan view from one direction, the absorption axis of the polarizer is oriented in one direction on the plane, and the polymerizable liquid crystal compound is aligned such that the absorption axis direction is the same as the specific one direction throughout the curved surface. In this specification, the absorption axis of the polarizer being oriented in one direction means a state where the absorption axis directions of the polarizer are substantially in the same direction, specifically, the deviation of the absorption axis direction of the polarizer in one curved surface connected as a surface is within 15°.

[0023] In the present invention, the polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (A)") contained in the polymerizable liquid crystal composition for forming a polarizer (hereinafter, also referred to as "polymerizable liquid crystal composition (A)") is a compound having at least one polymerizable group. Here, the polymerizable group refers to a group that can participate in a polymerization reaction by an active radical, an acid, or the like generated from a polymerization initiator. Examples of the polymerizable group of the polymerizable liquid crystal compound (A) include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, a (meth)acryloyl group, an oxiranyl group, an oxetanyl group, and the like. Among them, a radical polymerizable group is preferable, a (meth)acryloyl group, a vinyl group, and a vinyloxy group are more preferable, and a (meth)acryloyl group is even more preferable.

[0024] In the present invention, the polymerizable liquid crystal compound (A) is preferably a compound exhibiting smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizer with a high degree of alignment order can be formed. From the viewpoint of achieving a higher degree of alignment order, the liquid crystal state exhibited by the polymerizable liquid crystal compound (A) is more preferably a higher-order smectic phase (higher-order smectic liquid crystal state). Here, the higher-order smectic phase means a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, and a smectic L phase. Among these, the smectic B phase, the smectic F phase, and the smectic I phase are more preferable. The liquid crystallinity may be thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferable in terms of enabling precise film thickness control. Further, the polymerizable liquid crystal compound (A) may be a monomer, but may also be an oligomer or a polymer in which the polymerizable groups are polymerized.

[0025] The polymerizable liquid crystal compound (A) is not particularly limited as long as it is a liquid crystal compound having at least one polymerizable group, and known polymerizable liquid crystal compounds can be used. As the polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, for example, a compound represented by the following formula (A1) (hereinafter sometimes referred to as "polymerizable liquid crystal compound (A1)") can be mentioned. U 1 -V 1 -W 1 -(X 1 -Y 1 ) n -X 2 -W 2 -V 2 -U 2 (A1) [In formula (A1), X 1 and X 2Each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group, where the hydrogen atoms contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and the carbon atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom. However, X 1 and X 2 At least one of them is an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane-1,4-diyl group. Y 1 Is a single bond or a divalent linking group. n is 1 to 3. When n is 2 or more, a plurality of X 1 May be the same as or different from each other. X 2 May be the same as or different from any or all of the plurality of X 1 Also, when n is 2 or more, a plurality of Y 1 May be the same as or different from each other. From the viewpoint of liquid crystallinity, n is preferably 2 or more. U 1 Represents a hydrogen atom or a polymerizable group. U 2 Represents a polymerizable group. W 1 And W 2 Each independently is a single bond or a divalent linking group. V 1 And V 2 Each independently represents an optionally substituted alkanediyl group having 1 to 20 carbon atoms, and -CH2- constituting the alkanediyl group may be replaced with -O-, -CO-, -S- or -NH-.

[0026] In the polymerizable liquid crystal compound (A1), X 1 and X 2is, independently of one another, preferably a 1,4-phenylene group which may have a substituent, or a cyclohexane-1,4-diyl group which may have a substituent, and X 1 and X 2 at least one of which is a 1,4-phenylene group which may have a substituent, or a cyclohexane-1,4-diyl group which may have a substituent, and is preferably a trans-cyclohexane-1,4-diyl group. Examples of the substituent which the 1,4-phenylene group which may have a substituent or the cyclohexane-1,4-diyl group which may have a substituent may optionally have include alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group and butyl group, cyano group, and halogen atoms such as chlorine atom and fluorine atom. It is preferably unsubstituted.

[0027] Further, in the polymerizable liquid crystal compound (A1), in the formula (A1), the formula (A1-1): -(X 1 -Y 1 ) n -X 2 - (A1-1) [wherein X 1 , Y 1 , X 2 and n have the same meanings as described above, respectively.] It is preferable that the moiety represented by the following (hereinafter also referred to as partial structure (A1-1)) has an asymmetric structure in terms of easily exhibiting smectic liquid crystallinity. Examples of the polymerizable liquid crystal compound (A1) in which the partial structure (A1-1) has an asymmetric structure include, for example, a polymerizable liquid crystal compound (A1) in which n is 1 and one X 1 and X 2 have different structures from each other. Further, a compound in which n is 2 and two Y 1 have the same structure as each other, two X 1 have the same structure as each other, and one X 2 has a structure different from these two X 1 , a polymerizable liquid crystal compound (A1) in which one of the two X 1 bonded to W 1 is different from the other X 1 and the other X 1and X 2 has a structure different from that of the other X 1 X 2 There is also a polymerizable liquid crystal compound (A1) having the same structure as each other. Further, when n is 3, the three Y 1 are compounds having the same structure as each other, and among the three X 1 and one X 2 There is a polymerizable liquid crystal compound (A1) in which any one of them has a structure different from all of the other three.

[0028] Y 1 is preferably -CH2CH2-, -CH2O-, -CH2CH2O-, -COO-, -OCOO-, a single bond, -N=N-, -CR a =CR b -, -C≡C-, -CR a =N- or -CO-NR a -. R a and R b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y 1 is more preferably -CH2CH2-, -COO- or a single bond. When a plurality of Y 1 are present, the Y 2 bonded to X 1 is more preferably -CH2CH2- or -CH2O-. When X 1 and X 2 all have the same structure, it is preferable that two or more Y 1 having different bonding modes from each other are present. When a plurality of Y 1 having different bonding modes from each other are present, an asymmetric structure is formed, and thus smectic liquid crystallinity tends to be easily exhibited.

[0029] U 2 is a polymerizable group. U 1 is a hydrogen atom or a polymerizable group, and is preferably a polymerizable group. U 1 and U 2It is preferable that both are polymerizable groups, and it is more preferable that both are radically polymerizable groups. Examples of the polymerizable group include the same groups as those exemplified above as the polymerizable group of the polymerizable liquid crystal compound (A). U 1 The polymerizable group represented by U 2 and the polymerizable group represented by U 1 and U 2 It is preferable that at least one of them is a (meth)acryloyl group, and it is more preferable that both are (meth)acryloyl groups. Further, the polymerizable group may be in a polymerized state or an unpolymerized state, but preferably it is in an unpolymerized state.

[0030] V 1 and V 2 Examples of the alkanediyl group represented by V 1 and V 2 include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a decane-1,10-diyl group, a tetradecane-1,14-diyl group, an icosane-1,20-diyl group, and the like. V 1 and V 2 are preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably an alkanediyl group having 6 to 12 carbon atoms.

[0031] Examples of the substituent optionally possessed by the alkanediyl group include a cyano group and a halogen atom, etc., but the alkanediyl group is preferably unsubstituted, and more preferably an unsubstituted linear alkanediyl group.

[0032] W 1 and W 2 are each independently preferably a single bond, -O-, -S-, -COO- or -OCOO-, and more preferably a single bond or -O-.

[0033] The polymerizable liquid crystal compound (A) is not particularly limited as long as it is a polymerizable liquid crystal compound having at least one polymerizable group, and known polymerizable liquid crystal compounds can be used. It is preferably a smectic liquid crystal, and in terms of a structure that easily exhibits smectic liquid crystallinity, it preferably has an asymmetric molecular structure in the molecular structure. Specifically, it is more preferably a polymerizable liquid crystal compound having the following partial structures (A-a) to (A-i) and exhibiting smectic liquid crystallinity. From the viewpoint of easily exhibiting higher-order smectic liquid crystallinity, it is more preferable to have the partial structure of (A-a), (A-b) or (A-c). In the following (A-a) to (A-i), * represents a bond (single bond).

[0034] [Chemical formula]

[0035] Specific examples of the polymerizable liquid crystal compound (A) include compounds represented by formula (A-1) to formula (A-25). When the polymerizable liquid crystal compound (A) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably in the trans form.

[0036] [Chemical formula]

[0037] [Chemical formula]

[0038] [Chemical formula]

[0039] [Chemical formula]

[0040] [Chemistry]

[0041] Among these, at least one selected from the group consisting of compounds represented by formula (A-2), formula (A-3), formula (A-4), formula (A-5), formula (A-6), formula (A-7), formula (A-8), formula (A-13), formula (A-14), formula (A-15), formula (A-16) and formula (A-17) is preferred. As the polymerizable liquid crystal compound (A), one kind may be used alone, or two or more kinds may be used in combination.

[0042] The polymerizable liquid crystal compound (A) can be produced by a known method described in, for example, Lub et al., Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

[0043] In the present invention, the polymerizable liquid crystal composition (A) may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound (A). However, from the viewpoint of obtaining a polarizing layer with a high degree of orientation order, the ratio of the polymerizable liquid crystal compound (A) to the total mass of all the polymerizable liquid crystal compounds contained in the polymerizable liquid crystal composition (A) is preferably 51% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass or more.

[0044] When the polymerizable liquid crystal composition (A) contains two or more kinds of polymerizable liquid crystal compounds (A), at least one of them may be the polymerizable liquid crystal compound (A1), or all of them may be the polymerizable liquid crystal compound (A1). By combining a plurality of polymerizable liquid crystal compounds, it may be possible to temporarily maintain liquid crystallinity even at a temperature below the liquid crystal-crystalline phase transition temperature.

[0045] In the polymerizable liquid crystal composition (A), the content of the polymerizable liquid crystal compound is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and still more preferably 70 to 99% by mass, based on the solid content of the polymerizable liquid crystal composition (A). When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be high. In this specification, the solid content means the total amount of components obtained by removing volatile components such as solvents from the polymerizable liquid crystal composition (A). Hereinafter, in the polymerizable liquid crystal composition for forming a retardation layer and the like, it also means the total amount of components obtained by removing volatile components such as solvents from the target composition.

[0046] In the present invention, the polymerizable liquid crystal composition (A) for forming a polarizer contains a dichroic dye. Here, the dichroic dye means a dye having a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction. The dichroic dye that can be used in the present invention is not particularly limited as long as it has the above property, and it may be a dye or a pigment. Further, two or more dyes or pigments may be used in combination, or a dye and a pigment may be used in combination. Either only one kind may be used, or two or more kinds may be used in combination. Further, the dichroic dye may have polymerizability or liquid crystallinity.

[0047] As the dichroic dye, those having a maximum absorption wavelength (λ MAX ) in the range of 300 to 700 nm are preferable. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes.

[0048] Examples of the azo dye include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes. Bisazo dyes and trisazo dyes are preferable. For example, a compound represented by the formula (I) (hereinafter, also referred to as "compound (I)") can be mentioned. K 1 (-N=N-K 2 ) p -N=N-K 3 (I) [In formula (I), K 1 and K 3 each independently represent a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent. K 2 represents a p-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent heterocyclic group which may have a substituent. p represents an integer of 1 to 4. When p is an integer of 2 or more, the plurality of K 2 may be the same as or different from each other. In the range showing absorption in the visible region, the -N=N- bond may be replaced by a -C=C-, -COO-, -NHCO-, -N=CH- bond.]

[0049] Examples of the monovalent heterocyclic group include groups obtained by removing one hydrogen atom from heterocyclic compounds such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the divalent heterocyclic group include groups obtained by removing two hydrogen atoms from the heterocyclic compounds.

[0050] K 1 and K 3 The phenyl group, naphthyl group and monovalent heterocyclic group in, and K 2Examples of the substituents optionally possessed by the p-phenylene group, naphthalene-1,4-diyl group, and divalent heterocyclic group include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms and a polymerizable group, an alkenyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 20 carbon atoms such as a methoxy group, an ethoxy group, and a butoxy group; an alkoxy group having 1 to 20 carbon atoms and a polymerizable group; an alkyl fluoride group having 1 to 4 carbon atoms such as a trifluoromethyl group; a cyano group; a nitro group; a halogen atom; a substituted or unsubstituted amino group such as an amino group, a diethylamino group, and a pyrrolidino group (the substituted amino group means an amino group having one or two alkyl groups having 1 to 6 carbon atoms, an amino group having one or two alkyl groups having 1 to 6 carbon atoms and a polymerizable group, or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms. The unsubstituted amino group is -NH2.). etc. Examples of the polymerizable group include an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group, etc.

[0051] Among the compounds (I), compounds represented by any of the following formulas (I-1) to (I-8) are preferable. [Chemical formula] [In formulas (I-1) to (I-8), B 1 ~B 30 independently of each other, represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (the definitions of the substituted amino group and the unsubstituted amino group are as described above), a chlorine atom, or a trifluoromethyl group. n1 to n4 independently of each other represent an integer of 0 to 3. When n1 is 2 or more, the plurality of B 2 may be the same as or different from each other, When n2 is 2 or more, the plurality of B 6 may be the same as or different from each other, When n3 is 2 or more, the plurality of B 9may be the same as or different from each other, when n4 is 2 or more, a plurality of Bs 14 may be the same as or different from each other.]

[0052] As the anthraquinone dye, a compound represented by the formula (I-9) is preferable. [Chemical formula] [In formula (I-9), R 1 ~R 8 are, independently of each other, a hydrogen atom, -R x , -NH2, -NHR x , -NR x 2, -SR x or a halogen atom. R x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

[0053] As the oxazone dye, a compound represented by the formula (I-10) is preferable. [Chemical formula] [In formula (I-10), R 9 ~R 15 are, independently of each other, a hydrogen atom, -R x , -NH2, -NHR x , -NR x 2, -SR x or a halogen atom. R x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

[0054] As the acridine dye, a compound represented by the formula (I-11) is preferable. [Chemical formula] [In formula (I-11), R 16 ~R 23are, independently of each other, a hydrogen atom, -R x , -NH2, -NHR x , -NR x 2, -SR x or a halogen atom. R x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. In formula (I-9), formula (I-10) and formula (I-11), examples of the alkyl group having 1 to 6 carbon atoms of R x include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and the like, and examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a toluyl group, a xylyl group, a naphthyl group and the like.

[0055] As the cyanine dye, a compound represented by formula (I-12) and a compound represented by formula (I-13) are preferable.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0056] Among these dichroic dyes, azo dyes are highly linear and thus suitable for producing polarizers with excellent polarization performance. Therefore, in one embodiment of the present invention, the dichroic dye contained in the composition for forming a polarizing layer that forms a polarizer is preferably an azo dye.

[0057] In the present invention, the weight average molecular weight of the dichroic dye is usually 300 to 2000, preferably 400 to 1000.

[0058] In one embodiment of the present invention, the dichroic dye contained in the polymerizable liquid crystal composition (A) for forming a polarizer is preferably hydrophobic. When the dichroic dye is hydrophobic, the compatibility between the dichroic dye and the polymerizable liquid crystal compound is improved, and the dichroic dye and the polymerizable liquid crystal compound form a uniform phase state, and a polarizer having a high degree of alignment order can be obtained. In the present invention, the hydrophobic dichroic dye means a dye having a solubility of 1 g or less in 100 g of water at 25°C.

[0059] The content of the dichroic dye in the polymerizable liquid crystal composition (A) can be appropriately determined according to the type of the dichroic dye used, etc., but is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and still more preferably 0.1 to 12 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the dichroic dye is within the above range, it is difficult to disturb the alignment of the polymerizable liquid crystal compound, and a polarizer having a high degree of alignment order can be obtained.

[0060] In the present invention, the polymerizable liquid crystal composition (A) for forming a polarizer may contain a polymerization initiator. The polymerization initiator is a compound that can initiate the polymerization reaction of the polymerizable liquid crystal compound, and a photoinitiator is preferred in that it can initiate the polymerization reaction under lower temperature conditions. Specifically, photoinitiators that can generate active radicals or acids by the action of light are mentioned, and among them, photoinitiators that generate radicals by the action of light are preferred. The polymerization initiator can be used alone or in combination of two or more.

[0061] As the photopolymerization initiator, known photopolymerization initiators can be used. For example, as the photopolymerization initiator that generates active radicals, there are self-cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators. As the self-cleavage type photopolymerization initiator, self-cleavage type benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. can be used. Further, as the hydrogen abstraction type photopolymerization initiator, hydrogen abstraction type benzophenone compounds, benzoin ether compounds, benzyl ketal compounds, dibenzosuberone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, halogenoacetophenone compounds, dialkoxyacetophenone compounds, halogenobisimidazole compounds, halogenotriazine compounds, triazine compounds, etc. can be used.

[0062] As the photopolymerization initiator that generates an acid, iodonium salts, sulfonium salts, etc. can be used.

[0063] Among these, from the viewpoint of preventing the dissolution of the dye, the reaction at a low temperature is preferable, and from the viewpoint of the reaction efficiency at a low temperature, the self-cleavage type photopolymerization initiator is preferable, and particularly acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, and oxime ester compounds are preferable.

[0064] Specific examples of the photopolymerization initiator include the following. Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; Hydroxyacetophenone compounds such as oligomers of 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethan-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one; α-Aminoacetophenone compounds such as 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one; Oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)] and ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetoxyoxime); Acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; Benzophenone compounds such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone; Dialkoxyacetophenone compounds such as diethoxyacetophenone; Triazine compounds such as 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine, and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine. The photoinitiator may be appropriately selected, for example, in relation to the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition (A) from the above photoinitiators.

[0065] Also, commercially available photoinitiators may be used. Examples of commercially available photoinitiators include Irgacure (registered trademark) 907, 184, 651, 819, 250, and 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by BASF); Omnirad BCIM, Esacure 1001M, Esacure KIP160 (manufactured by IDM Resins B.V.); Seikol (registered trademark) BZ, Z, and BEE (manufactured by Seiko Chemical Co., Ltd.); Kayacure (registered trademark) BP100 and UVI-6992 (manufactured by Dow Chemical Co., Ltd.); Adeka Optomer SP-152, N-1717, N-1919, SP-170, Adeka Arcles NCI-831, Adeka Arcles NCI-930 (manufactured by Adeka Corporation); TAZ-A and TAZ-PP (manufactured by Nippon Sieber Hegner Co., Ltd.); and TAZ-104 (manufactured by Sankyo Chemical Co., Ltd.); etc.

[0066] In the polymerizable liquid crystal composition (A), the content of the polymerization initiator is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, still more preferably 2 to 8 parts by mass, and particularly preferably 4 to 8 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the above range, the polymerization reaction of the polymerizable liquid crystal compound can be carried out without significantly disturbing the alignment of the polymerizable liquid crystal compound.

[0067] From the viewpoints of line contamination during production and handling, the polymerization rate of the polymerizable liquid crystal compound in the present invention is preferably 60% or more, more preferably 65% or more, and still more preferably 70% or more.

[0068] In the present invention, the polarizer preferably contains a leveling agent. That is, the polymerizable liquid crystal composition (A) for forming the polarizer preferably contains a leveling agent. The leveling agent has a function of adjusting the fluidity of the polymerizable liquid crystal composition (A) and making the coating film obtained by applying the polymerizable liquid crystal composition (A) flatter. When the polarizer contains a leveling agent, a smooth polarizer with little coating unevenness can be obtained even on curved surfaces of various shapes, particularly curved surfaces with a relatively large curvature, which is advantageous for improving the appearance and optical properties of the polarizing plate.

[0069] Specific examples of the leveling agent include surfactants, and at least one selected from the group consisting of leveling agents mainly composed of polyacrylate compounds and leveling agents mainly composed of fluorine atom-containing compounds is preferred. The leveling agent can be used alone or in combination of two or more.

[0070] Examples of the leveling agent mainly composed of a polyacrylate compound include "BYK-350", "BYK-35"2", "BYK-353", "BYK-354", "BYK-355", "BYK-358N", "BYK-361N", "BYK-380", "BYK-381", and "BYK-392" (BYK Chemie).

[0071] Examples of the leveling agent mainly composed of a fluorine atom-containing compound include "Megafac (registered trademark) R-08", "R-30", "R-90", "F-410", "F-411", "F-443", "F-445", "F-470", "F-471", "F-477", "F-479", "F-482", and "F-483" (DIC Corporation); "Surflon (registered trademark) S-381", "S-382", "S-383", "S-393", "SC-101", "SC-105", "KH-40", and "SA-100" (AGC Seimi Chemical Co., Ltd.); "E1830", "E5844" (Daikin Fine Chemical Research Institute Co., Ltd.); "F-Top EF301", "F-Top EF303", "F-Top EF351", and "F-Top EF352" (Mitsubishi Materials Electronic Chemicals Co., Ltd.).

[0072] When the polymerizable liquid crystal composition (A) contains a leveling agent, the content is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, it is easy to align the polymerizable liquid crystal compound, and unevenness is less likely to occur, and a more smooth polarizer tends to be obtained.

[0073] The polymerizable liquid crystal composition (A) may contain other additives in addition to the leveling agent. Examples of other additives include polymerizable non-liquid crystal compounds, photosensitizers, antioxidants, release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When the polymerizable liquid crystal composition (A) contains other additives, the content of the other additives is preferably more than 0% and 20% by mass or less, more preferably more than 0% and 10% by mass or less, based on the solid content of the polymerizable liquid crystal composition (A).

[0074] By blending a photosensitizer into the polymerizable liquid crystal composition (A), the polymerization reaction of the polymerizable liquid crystal compound can be further promoted. Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone (e.g., 2,4 - diethylthioxanthone, 2 - isopropylthioxanthone, etc.); anthracene compounds such as anthracene and alkoxy group - containing anthracene (e.g., dibutoxyanthracene, etc.); phenothiazine, rubrene, and the like. The photosensitizer can be used alone or in combination of two or more kinds.

[0075] When the polymerizable liquid crystal composition (A) contains a photosensitizer, its content can be appropriately determined according to the types and amounts of the polymerization initiator and the polymerizable liquid crystal compound. However, with respect to 100 parts by mass of the polymerizable liquid crystal compound, 0.1 to 30 parts by mass is preferable, 0.5 to 10 parts by mass is more preferable, and 0.5 to 8 parts by mass is even more preferable.

[0076] The polymerizable liquid crystal composition (A) can be produced by a conventionally known method for preparing a composition for forming a polarizer. Usually, it can be prepared by mixing and stirring a polymerizable liquid crystal compound, a dichroic dye, and, if necessary, a polymerization initiator and the above - mentioned additives, etc. Also, since compounds generally exhibiting smectic liquid crystallinity have a high viscosity, from the viewpoint of improving the coatability of the polymerizable liquid crystal composition (A) and facilitating the formation of a polarizer, the viscosity can be adjusted by adding a solvent.

[0077] The solvent used in the alignment liquid crystal composition (A) can be appropriately selected according to the solubility of the polymerizable liquid crystal compound and the dichroic dye to be used. Specifically, for example, water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, alcohol solvents such as propylene glycol monomethyl ether, ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, ester solvents such as ethyl lactate, acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, ketone solvents such as methyl isobutyl ketone, pentane, hexane, aliphatic hydrocarbon solvents such as heptane, toluene, aromatic hydrocarbon solvents such as xylene, nitrile solvents such as acetonitrile, tetrahydrofuran, ether solvents such as dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents can be used alone or in combination of two or more. The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and still more preferably 180 to 600 parts by mass with respect to 100 parts by mass of the solid content of the polymerizable liquid crystal composition (A).

[0078] In the present invention, the polarizer is preferably a polarizer having a high degree of orientation order. A polarizer having a high degree of orientation order can obtain Bragg peaks derived from higher-order structures such as a hexagonal phase or a crystal phase in X-ray diffraction measurement. The Bragg peak means a peak derived from the surface periodic structure of molecular orientation. Therefore, it is preferable that the polarizer constituting the polarizing plate of the present invention shows a Bragg peak in X-ray diffraction measurement. That is, in the polarizer constituting the polarizing plate of the present invention, it is preferable that the polymerizable liquid crystal compound or its polymer is oriented so that the polarizer shows a Bragg peak in X-ray diffraction measurement, and it is more preferable that the molecules of the polymerizable liquid crystal compound are "horizontally oriented" in the direction of absorbing light. In the present invention, a polarizer having a surface periodic interval of molecular orientation of 3.0 to 6.0 Å is preferable. A high degree of orientation order showing a Bragg peak can be realized by controlling the type of the polymerizable liquid crystal compound used, the type and amount of the dichroic dye, and the type and amount of the polymerization initiator, etc.

[0079] The polarizer can be obtained, for example, by forming a coating film of the polymerizable liquid crystal composition (A) on an optical alignment film provided on a curved substrate, removing the solvent from the coating film, phase-transitioning the polymerizable liquid crystal compound to a liquid crystal phase (smectic phase), and polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal phase.

[0080] As a method of applying the polymerizable liquid crystal composition (A) on the optical alignment film, from the viewpoint of being less likely to cause coating unevenness and easily obtaining a uniform coating film of the polymerizable liquid crystal composition (A) even for a curved surface or a concave curved surface having a relatively large curvature, it is preferable to adopt a coating method such as a spin coating method, a spray method, or a dip coating method.

[0081] Next, a dry coating film is formed by removing the solvent by drying or the like under the condition that the polymerizable liquid crystal compound contained in the coating film obtained from the polymerizable liquid crystal composition (A) does not polymerize. Examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method, and a reduced-pressure drying method.

[0082] Furthermore, in order to cause the polymerizable liquid crystal compound to undergo a phase transition to the liquid phase, the temperature is raised to a temperature equal to or higher than the temperature at which the polymerizable liquid crystal compound undergoes a phase transition to the liquid phase and then lowered to cause the polymerizable liquid crystal compound to undergo a phase transition to the liquid crystal phase (smectic phase). Such a phase transition may be carried out after removal of the solvent in the coating film, or may be carried out simultaneously with the removal of the solvent.

[0083] While maintaining the liquid crystal state of the polymerizable liquid crystal compound, the polymerizable liquid crystal compound is polymerized to form a polarizer as a cured product of the polymerizable liquid crystal composition (A). As the polymerization method, a photopolymerization method is preferable. In photopolymerization, the light irradiated on the dry coating film is appropriately selected according to the type of the polymerizable liquid crystal compound contained in the dry coating film (particularly, the type of the polymerizable group possessed by the polymerizable liquid crystal compound), the type of the polymerization initiator, and their amounts. Specific examples thereof include one or more types of active energy rays and electron beams selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays. Among them, ultraviolet light is preferable in terms of easy control of the progress of the polymerization reaction and the availability of widely used photopolymerization apparatuses in the art. By ultraviolet light, it is preferable to select the types of the polymerizable liquid crystal compound and the polymerization initiator contained in the polymerizable liquid crystal composition (A) so that photopolymerization is possible. Further, during polymerization, the polymerization temperature can also be controlled by irradiating light while cooling the dry coating film by an appropriate cooling means. During photopolymerization, a patterned polarizing layer can also be obtained by performing masking, development, or the like.

[0084] Examples of the light source for the active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources emitting in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, and the like.

[0085] The ultraviolet irradiation intensity is usually 10 to 3,000 mW / cm 2It is so. The ultraviolet irradiation intensity is preferably the intensity in the wavelength region effective for activating the polymerization initiator. The time for irradiating light is usually from 0.1 second to 10 minutes, preferably from 1 second to 5 minutes, more preferably from 5 seconds to 3 minutes, and still more preferably from 10 seconds to 1 minute. When irradiated once or a plurality of times with such an ultraviolet irradiation intensity, the integrated light quantity is 10 to 3,000 mJ / cm 2 , preferably 50 to 2,000 mJ / cm 2 , more preferably 100 to 1,000 mJ / cm 2 .

[0086] By performing photopolymerization, the polymerizable liquid crystal compound polymerizes while maintaining the liquid crystal state of the liquid crystal phase, particularly the smectic phase, preferably the higher-order smectic phase, and a polarizer is formed. The polarizer obtained by polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal state of the smectic phase has an advantage of high polarizing performance compared with a conventional host-guest type polarizing film, that is, a polarizing layer composed of a liquid crystal state of a nematic phase, due to the action of the dichroic dye. Further, it also has an advantage of excellent strength compared with a coating of only a dichroic dye or a lyotropic liquid crystal.

[0087] The thickness of the polarizer can be appropriately selected according to the display device to be applied, and is preferably a film of 0.1 to 5 μm, more preferably 0.3 to 4 μm, and still more preferably 0.5 to 3 μm. When the film thickness of the polarizer is equal to or greater than the above lower limit value, it is easy to prevent the necessary light absorption from not being obtained, and when it is equal to or less than the above upper limit value, it is easy to suppress the occurrence of alignment defects due to a decrease in the alignment regulating force by the photoalignment film.

[0088] When forming a polarizer, by applying the polymerizable liquid crystal composition (A) onto the alignment film, it becomes easier to align the polymerizable liquid crystal compound and the dichroic dye in a desired direction. The polarizing plate of the present invention uses a photo-alignment film as the alignment film. By using a photo-alignment film capable of arbitrarily controlling the direction of the alignment regulating force by selecting the polarization direction of the polarized light to be irradiated, it is difficult to provide an alignment film having an alignment regulating force by physically changing the surface of the alignment film such as a rubbing alignment film that has been widely used conventionally. In a curved surface shape, for example, a curved surface with a large curvature or a concave curved surface, it is easy to obtain an alignment film with high quality by accurately controlling the alignment angle, so a polarizer with higher alignment accuracy can be formed. In order to suppress the decrease in the alignment regulating force by the photo-alignment film and sufficiently enhance the alignment accuracy, in the polarizing plate of the present invention, usually, the polarizer is laminated adjacent to the photo-alignment film.

[0089] The photo-alignment film is obtained, for example, by applying a composition containing a polymer, oligomer, or monomer having a photoreactive group (hereinafter also referred to as "polymer having a photoreactive group, etc.") and a solvent (hereinafter also referred to as "photo-alignment film forming composition") onto a curved substrate and irradiating with polarized light (preferably, polarized UV). When the polymer, etc. contained in the photo-alignment film forming composition has the same reactive group (for example, (meth)acryloyl group) as the polymerizable group of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition (A), the adhesion between the photo-alignment film and the polarizer tends to improve, which can be advantageous in suppressing the occurrence of floating or peeling of the polarizer in a polarizing plate with a curved surface shape.

[0090] The photoreactive group refers to a group that generates liquid crystal alignment ability upon light irradiation. Specifically, it includes groups involved in photoreactions that are the origin of liquid crystal alignment ability, such as orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodegradation reaction of molecules caused by light irradiation. Among them, groups involved in dimerization reaction or photocrosslinking reaction are preferred in terms of excellent orientation. As the photoreactive group, a group having an unsaturated bond, particularly a double bond, is preferred, and a group having at least one selected from the group consisting of carbon-carbon double bond (C = C bond), carbon-nitrogen double bond (C = N bond), nitrogen-nitrogen double bond (N = N bond), and carbon-oxygen double bond (C = O bond) is particularly preferred.

[0091] Examples of the photoreactive group having a C = C bond include vinyl group, polyene group, stilbene group, stilbazole group, stilbazolium group, chalcone group, and cinnamoyl group. Examples of the photoreactive group having a C = N bond include groups having structures such as aromatic Schiff base and aromatic hydrazone. Examples of the photoreactive group having an N = N bond include azobenzene group, azonaphthalene group, aromatic heterocyclic azo group, bisazo group, formazan group, and groups having an azoxybenzene structure. Examples of the photoreactive group having a C = O bond include benzophenone group, coumarin group, anthraquinone group, and maleimide group. These groups may have substituents such as alkyl group, alkoxy group, aryl group, allyloxy group, cyano group, alkoxycarbonyl group, hydroxyl group, sulfonic acid group, and halogenated alkyl group.

[0092] Among them, photoreactive groups involved in photodimerization reaction are preferred. Cinnamoyl group and chalcone group are preferred in that a relatively small amount of polarized light irradiation required for photoalignment is needed, and a photoalignment film excellent in thermal stability and stability over time can be easily obtained. As the polymer having a photoreactive group, etc., a polymer having a cinnamoyl group in which the terminal portion of the polymer side chain has a cinnamic acid structure is particularly preferred.

[0093] The number average molecular weight of the polymer having a photoreactive group for forming the photo-aligned film is preferably from 20,000 to 100,000, more preferably 22,000 or more, still more preferably 25,000 or more, and also more preferably 90,000 or less, still more preferably 80,000 or less. When the number average molecular weight of the polymer having a photoreactive group is within the above range, the adhesion to the layer adjacent to the photo-aligned film is likely to be improved, and a polarizing plate in which a curved substrate and a polarizer are laminated with good adhesion via the photo-aligned film can be obtained. The number average molecular weight of the polymer having a photoreactive group can be controlled by the amount of the monomer used in the photo-aligned film-forming composition, the type and amount of the polymerization initiator, etc. Here, the "number average molecular weight of the polymer having a photoreactive group" substantially corresponds to the number average molecular weight of the polymer constituting the cured photo-aligned film, and can be calculated by measuring the cured photo-aligned film itself using a measuring instrument such as gel permeation chromatography.

[0094] A photo-alignment induction layer can be formed by applying, for example, the photo-aligned film-forming composition onto a curved substrate. Examples of the solvent contained in the composition include the same solvents as those exemplified above as solvents that can be used when forming a polarizer, and can be appropriately selected according to the solubility of the polymer having a photoreactive group and the like.

[0095] The content of the polymer having a photoreactive group and the like in the photo-aligned film-forming composition can be appropriately adjusted according to the type of the polymer and the like and the thickness of the target photo-aligned film, but it is preferably at least 0.2% by mass, more preferably in the range of 0.3 to 10% by mass, based on the mass of the photo-aligned film-forming composition. The photo-aligned film-forming composition may contain a polymer material such as polyvinyl alcohol or polyimide and a photosensitizer as long as the characteristics of the photo-aligned film are not significantly impaired.

[0096] Examples of the method for applying the photo-aligned film-forming composition onto a curved substrate and the method for removing the solvent from the applied photo-aligned film-forming composition include the same methods as those for applying the polymerizable liquid crystal composition (A) onto the photo-aligned film and removing the solvent from the formed coating film.

[0097] The polarized light irradiation may be in a form of directly irradiating the polarized UV onto the composition for forming an optically oriented film from which the solvent has been removed and which is applied on the curved substrate, or in a form of irradiating the polarized light from the curved substrate side and transmitting the polarized light for irradiation. Also, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength region where a photoreactive group such as a polymer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) in the range of 250 to 400 nm in wavelength is particularly preferable. Examples of the light source used for the polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and high-pressure mercury lamps, ultra-high-pressure mercury lamps and metal halide lamps are more preferable. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps and metal halide lamps are preferable because they have a high emission intensity of ultraviolet rays with a wavelength of 313 nm. By passing the light from the light source through an appropriate polarizer and irradiating, polarized UV can be irradiated. As such a polarizer, a polarizing filter, a polarizing prism such as a Glan-Taylor or Glan-Thompson, or a wire grid type polarizer can be used.

[0098] Note that, if masking is performed during the polarized light irradiation, a plurality of regions (patterns) having different liquid crystal alignment directions can also be formed.

[0099] The thickness of the optically oriented film is preferably 10 to 5000 nm, more preferably 10 to 1000 nm, and still more preferably 30 to 300 nm. When the thickness of the optically oriented film is within the above range, good adhesion at the interface with the polarizer or the interface with the curved substrate can be exhibited, while the alignment regulating force can be exerted, and a polarizer can be formed with a high alignment order.

[0100] The polarizing plate of the present invention may include layers other than the curved substrate, the optically oriented film and the polarizer as long as it does not affect the effects of the present invention. Examples of such other layers include a protective layer, a hard coat layer, a primer layer, an adhesive layer, etc. for the purpose of protecting or reinforcing the polarizer.

[0101] The polarizing plate of the present invention is, for example, (a) a step of forming an optically oriented film on a curved substrate, (b) a step of forming a coating film of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound and a dichroic dye on the optically oriented film, and (c) a step of forming a polarizer by phase-transitioning the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition into a smectic liquid crystal phase and then polymerizing the polymerizable liquid crystal compound while maintaining the smectic liquid crystal state It can be manufactured by a method including. The above steps (a), (b), and (c) can be carried out according to the respective methods described in the previous paragraphs as a method of forming an optically oriented film on a curved substrate, a method of forming a coating film of the polymerizable liquid crystal composition (A), and a method of forming a polarizer from the coating film of the polymerizable liquid crystal composition (A), respectively.

[0102] The present invention also targets an elliptical polarizing plate including the polarizing plate of the present invention and a retardation layer having a quarter-wave plate function. In the elliptical polarizing plate of the present invention, the retardation layer is preferably a coating layer, and more preferably a cured product of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound. When the retardation layer is a coating layer, wrinkles and distortions are less likely to occur in the retardation layer having a curved surface shape, and it is likely to become a retardation layer capable of exhibiting high optical characteristics.

[0103] In the present invention, the retardation layer having a quarter-wave plate function means the following formula (2): 100 nm ≦ Re(550) ≦ 170 nm (2) [In formula (2), Re(λ) represents the in-plane retardation value of the retardation layer at a wavelength of λ nm] It means a layer that satisfies. By satisfying the above formula (2), it becomes a retardation layer that functions as a λ / 4 plate, and when an elliptical polarizing plate including the retardation layer is applied to an organic EL display device or the like, the effect of improving the front reflection hue (the effect of suppressing coloring) is likely to be enhanced. A more preferable range of the in-plane retardation value of the retardation layer is 130 nm ≦ Re(550) ≦ 150 nm.

[0104] Further, the retardation layer satisfies the following formulas (3) and (4): Re(450) / Re(550) ≦ 1.00 (3) 1.00 ≦ Re(650) / Re(550) (4) [In the formula, Re(λ) represents the in-plane retardation value of the retardation layer at a wavelength of λ nm.] It is preferably satisfied. When the retardation layer satisfies formulas (3) and (4), the retardation layer exhibits so-called inverse wavelength dispersion in which the in-plane retardation value at a short wavelength is smaller than the in-plane retardation value at a long wavelength. An elliptical polarizing plate having such a retardation layer tends to be excellent in the front color tone when incorporated into an organic EL display device or the like. From the viewpoint of improving the inverse wavelength dispersion and further enhancing the effect of improving the reflection color tone in the front direction of the elliptical polarizing plate, Re(450) / Re(550) is preferably 0.70 or more, more preferably 0.78 or more, and preferably 0.92 or less, more preferably 0.90 or less, still more preferably 0.87 or less, particularly preferably 0.86 or less, and even more particularly preferably 0.85 or less. Further, Re(650) / Re(550) is preferably 1.01 or more, more preferably 1.02 or more.

[0105] The above in-plane retardation value can be adjusted by the film thickness d of the retardation layer. Since the in-plane retardation value is determined by the formula Re(λ) = (nx(λ) - ny(λ)) × d (d represents the thickness of the target retardation layer, nx represents the principal refractive index at a wavelength of λ nm in the direction parallel to the plane of the retardation layer in the refractive index ellipsoid formed by the retardation layer, and ny represents the refractive index at a wavelength of λ nm in the direction parallel to the plane of the retardation layer and orthogonal to the direction of nx in the refractive index ellipsoid formed by the retardation layer), in order to obtain a desired in-plane retardation value (Re(λ): the in-plane retardation value of the retardation layer at a wavelength of λ (nm)), it is only necessary to adjust the three-dimensional refractive index and the film thickness d.

[0106] In the present invention, as the polymerizable liquid crystal compound for forming the retardation layer, it can be appropriately selected from the polymerizable liquid crystal compounds conventionally known in the field of retardation films according to the desired optical properties.

[0107] The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. As the polymerizable liquid crystal compound, generally, polymers (cured products) obtained by polymerizing the polymerizable liquid crystal compound alone in an oriented state in a specific direction include polymerizable liquid crystal compounds showing positive wavelength dispersion and polymerizable liquid crystal compounds showing negative wavelength dispersion. In the present invention, only one type of polymerizable liquid crystal compound may be used, or both types of polymerizable liquid crystal compounds may be mixed and used.

[0108] Examples of the polymerizable liquid crystal compound capable of forming the retardation layer in the present invention include polymerizable liquid crystal compounds as described in JP-A-2011-207765.

[0109] The retardation layer can be obtained by applying a polymerizable liquid crystal composition for forming a retardation layer (hereinafter also referred to as "polymerizable liquid crystal composition (B)") containing a polymerizable liquid crystal compound, a solvent, and additives such as a polymerization initiator and a leveling agent as necessary, onto a substrate or an alignment film, drying the coating film, and polymerizing the polymerizable liquid crystal compound by light irradiation or the like while maintaining the alignment state after aligning the polymerizable liquid crystal compound in the polymerizable liquid crystal composition (B). Examples of the solvent, polymerization initiator, and additives constituting the polymerizable liquid crystal composition (B) are the same as those exemplified above as the solvent, polymerization initiator, and additives that can be used for the polymerizable liquid crystal composition (A) for forming a polarizer.

[0110] From the viewpoint of easily imparting a desired alignment regulating force with high accuracy to various curved surface shapes, the alignment film used for forming the retardation layer is preferably a photo-alignment film. Examples of the photo-alignment film and the method for forming the retardation layer on the photo-alignment film include the same photo-alignment films, methods, and conditions as those exemplified in the method for forming a polarizer, and they may be appropriately selected according to the desired alignment regulating force and the configuration of the retardation layer.

[0111] The thickness of the retardation layer can be appropriately selected according to the display device or the like to which it is applied. From the viewpoints of adhesion and thinning of the film, etc., it is preferably 0.1 to 5 μm, more preferably 0.2 to 4 μm, and still more preferably 0.4 to 3 μm.

[0112] In the elliptical polarizing plate of the present invention, it is preferable that the retardation layer is directly formed on the polarizing plate of the present invention via an alignment film, or a polarizer is formed on the retardation layer formed on a curved substrate via an alignment film via an optical alignment film. Instead of laminating a separately manufactured polarizing plate and a retardation layer via, for example, an adhesive layer, a polymerizable liquid crystal composition (B) is applied on a polarizing plate having a curved surface shape to form a retardation layer, or a polymerizable liquid crystal composition (A) is applied on a curved substrate on which a retardation layer is formed to form a polarizer. When laminating the polarizing plate of the present invention and the retardation layer, the occurrence of wrinkles and distortion on the laminated surface having a curved surface shape can be suppressed, and an elliptical polarizing plate excellent in appearance characteristics and optical characteristics can be obtained. Therefore, the elliptical polarizing plate of the present invention preferably does not contain an adhesive layer between the polarizer and the retardation layer.

[0113] When laminating the polarizer and the retardation layer of the present invention, it is preferable to laminate them such that the slow axis (optical axis) of the retardation layer and the absorption axis of the polarizer are substantially 45°. By laminating the slow axis (optical axis) of the retardation layer and the absorption axis of the polarizer so as to be substantially 45°, the function as an elliptical polarizing plate can be obtained. Note that "substantially 45°" is usually in the range of 45 ± 5°.

[0114] The polarizing plate and the elliptical polarizing plate of the present invention can be used in various display devices such as liquid crystal display devices and organic EL display devices of flexible image display devices, etc., sunglasses, lens filters, and the like. When using the polarizing plate and / or the elliptical polarizing plate of the present invention for the above various applications, the separately manufactured polarizing plate and / or the elliptical polarizing plate of the present invention may be incorporated into various articles, or the members constituting the various articles may be used as a curved substrate to manufacture the polarizing plate and / or the elliptical polarizing plate of the present invention and then incorporated as a constituent member of the various articles.

[0115] The flexible image display device having the elliptical polarizing plate of the present invention preferably further includes a window and a touch panel touch sensor. The flexible image display device includes, for example, a laminate for a flexible image display device and an organic EL display panel. The laminate for a flexible image display device is disposed on the viewing side with respect to the organic EL display panel and is configured to be foldable. As the laminate for a flexible image display device, in addition to the above-described elliptical polarizing plate of the present invention, a window, a touch panel touch sensor, etc. may be included. The lamination order thereof is arbitrary, but it is preferable that they are laminated in the order of a window, an elliptical polarizing plate, a touch panel touch sensor, or a window, a touch panel touch sensor, an elliptical polarizing plate from the viewing side.

[0116] It is preferable that an elliptical polarizing plate is present on the viewing side of the touch panel touch sensor because the pattern of the touch panel touch sensor becomes difficult to be visually recognized and the visibility of the display image is improved. Each member can be laminated using an adhesive, an adhesive agent, or the like. Further, the laminate for a flexible image display device can include a light-shielding pattern formed on at least one surface of any layer of the window, the elliptical polarizing plate, and the touch panel touch sensor.

[0117] The window is disposed on the viewing side of the flexible image display device and plays a role of protecting other components from external impacts or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer, but the window in a flexible image display device is not as rigid and hard as glass and has flexible characteristics. The window is made of a flexible transparent substrate and may include a hard coat layer on at least one surface.

[0118] The transparent substrate preferably has a visible light transmittance of 70% or more, more preferably 80% or more. As the transparent substrate, any transparent polymer film can be used. Among them, a polyamide film, a polyamideimide film or a polyimide film, a polyester-based film, an olefin-based film, an acrylic film, or a cellulose-based film, which are excellent in transparency and heat resistance, is preferable. It is also preferable to disperse inorganic particles such as silica, organic fine particles, rubber particles, etc. in the polymer film.

[0119] The thickness of the transparent substrate is preferably 5 to 200 μm, more preferably 20 to 100 μm.

[0120] A hard coat layer may be provided on at least one surface of the transparent substrate constituting the window. The thickness of the hard coat layer is not particularly limited, and may be, for example, 2 to 100 μm. When the thickness of the hard coat layer is within the above range, it is easy to ensure sufficient impact resistance, scratch resistance, and bending resistance.

[0121] The hard coat layer can be formed by curing a hard coat forming composition containing a reactive material that forms a crosslinked structure by irradiating active energy rays or thermal energy, but is preferably formed by curing with active energy rays. Active energy rays are defined as energy rays that can decompose a compound that generates active species to generate active species. Examples of active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays, and electron beams, and ultraviolet rays are particularly preferred. The hard coat forming composition usually contains at least one of a radical polymerizable compound and a cationic polymerizable compound, and a polymerization initiator. The radical polymerizable compound, cationic polymerizable compound, and polymerization initiator are not particularly limited, and examples thereof include those conventionally known. The hard coat composition can further contain one or more selected from the group consisting of a solvent and an additive. The solvent can be used without limitation as long as it can dissolve or disperse the polymerizable compound and the polymerization initiator, and is known as a solvent for a composition for forming a hard coat in the field of optical films. Examples of the additive include inorganic particles, a leveling agent, a stabilizer, a surfactant, an antistatic agent, a lubricant, and an antifouling agent.

[0122] The touch panel touch sensor is used as an input means. Various modes such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and a capacitance method have been proposed as the touch panel touch sensor, and any method may be used. Among them, the capacitance method is preferred. The capacitance type touch panel touch sensor is divided into an active area and an inactive area located outside the outline of the active area. The active area is an area corresponding to the area (display part) where the screen is displayed on the display panel and is an area where the touch of the user is detected, and the inactive area is an area corresponding to the area (non-display part) where the screen is not displayed on the display device. The touch panel touch sensor can include a flexible substrate; a sensing pattern formed in the active area of the substrate; and each sensing line formed in the inactive area of the substrate and connected to an external drive circuit via the sensing pattern and a pad part.

[0123] The substrate, sensing pattern, and each sensing line having flexible characteristics are not particularly limited, and materials applicable in the relevant technical field can be selected for each of them.

[0124] As the substrate having flexible characteristics, for example, a substrate composed of the same material as the transparent substrate of the window can be used. The substrate of the touch panel touch sensor preferably has a toughness of 2,000 MPa% or more from the perspective of crack suppression of the touch panel touch sensor, and more preferably has a toughness of 2,000 MPa% to 30,000 MPa%. Here, the toughness is defined as the lower area of the curve up to the breaking point in the stress (MPa)-strain (%) curve (Stress-strain curve) obtained through the tensile experiment of the polymer material.

[0125] Each layer (window, elliptical polarizing plate, touch panel touch sensor) forming the laminate for the flexible image display device can be formed by an adhesive. As the adhesive, water-based adhesives, organic solvent-based, solventless adhesives, solid adhesives, solvent-evaporating adhesives, moisture-curing adhesives, heat-curing adhesives, anaerobic-curing adhesives, active energy ray-curing adhesives, curing agent-mixed adhesives, hot-melt adhesives, pressure-sensitive adhesives (adhesives), re-wetting adhesives, etc., which are commonly used, can be used. Among them, water-based solvent-evaporating adhesives, active energy ray-curing adhesives, and adhesives are preferably used. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive force, etc., but usually, it is 0.01 μm to 500 μm, preferably 0.1 μm to 300 μm. When there are a plurality of adhesive layers in the laminate for the flexible image display device, the types and thicknesses of the adhesives constituting each adhesive layer may be the same or different.

Examples

[0126] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the Examples and Comparative Examples, “%” and “parts” are “mass %” and “parts by mass” unless otherwise specified.

[0127] 1. Example 1 (1) Preparation of Composition for Forming Alignment Film The following components were mixed, and the resulting mixture was stirred at 80 °C for 1 hour to obtain a composition for forming a photo-alignment film. · 2 parts of a polymer having a photoreactive group shown below (number average molecular weight: about 28,000)

Chemical formula

[0128] (2) Preparation of Composition for Forming Polarizer The following components were mixed and stirred at 80 °C for 1 hour to obtain a composition for forming a polarizer. As the dichroic dyes, the following dichroic dye (1), dichroic dye (2), and dichroic dye (3) described in the examples of JP-A-2013-101328 were used.

[0129] · 75 parts of a polymerizable liquid crystal compound represented by formula (1-6)

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0130] (3) Manufacture of polarizing plate A substrate obtained by subjecting the surface of a glass concave lens (SLB-30-50N manufactured by OptoSigma) to corona treatment (AGF-B10, manufactured by Kasuga Electric Co., Ltd.) was used as a curved substrate. After applying the above composition for forming an optical alignment film on the surface subjected to corona treatment using a spin coater, it was dried in a drying oven set at 120 °C for 1 minute to obtain a coating film for an optical alignment film. On the coating film for the optical alignment film, polarized UV was irradiated onto the lens at an integrated light quantity of 50 mJ / cm 2 (standard of 313 nm) using a polarized UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.) to form an optical alignment film. After applying the above composition for forming a polarizer on the obtained optical alignment film using a spin coater, it was dried in a drying oven set at 110 °C for 1 minute. Then, using a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio Inc.), ultraviolet rays were irradiated (under a nitrogen atmosphere, wavelength: 365 nm, integrated light quantity at wavelength 365 nm: 1000 mJ / cm 2 ) to form a polarizer in which the polymerizable liquid crystal compound and the dichroic dye were aligned, and a polarizing plate composed of a curved substrate / optical alignment film / polarizer was obtained. Regarding the obtained polarizing plate, it was confirmed that it had polarizing performance by arranging it through another separately prepared polarizing plate in the same manner as in the method described in paragraph

[0321] of JP-A-2015-163935 so as to be para-nicol and cross-nicol.

[0131] (4) Evaluation of the laminated state Regarding the obtained polarizing plate, the laminated state was visually confirmed. The results are shown in Table 1. ○: No wrinkles or coating unevenness are observed. △: Some coating unevenness is observed. ×: A large number of wrinkles are observed.

[0132] 2. Example 2 A substrate obtained by subjecting the surface of a concave glass lens (SLB-30-70N manufactured by OptoSigma) to corona treatment (AGF-B10 manufactured by Kasuga Electric Co., Ltd.) was used as the curved substrate, and a polarizing plate composed of a curved substrate / photo-alignment film / polarizer was obtained in the same manner as in Example 1. Similar to Example 1, it was confirmed that it had polarization performance, and the laminated state was evaluated. The results are shown in Table 1.

[0133] 3. Example 3 A substrate obtained by subjecting the surface of a concave glass lens (SLB-30-100N manufactured by OptoSigma) to corona treatment (AGF-B10 manufactured by Kasuga Electric Co., Ltd.) was used as the curved substrate, and a polarizing plate composed of a curved substrate / photo-alignment film / polarizer was obtained in the same manner as in Example 1. Similar to Example 1, it was confirmed that it had polarization performance, and the laminated state was evaluated. The results are shown in Table 1.

[0134] 4. Example 4 A substrate obtained by subjecting the surface of a concave glass lens (SLB-30-200N manufactured by OptoSigma) to corona treatment (AGF-B10 manufactured by Kasuga Electric Co., Ltd.) was used as the curved substrate, and a polarizing plate composed of a curved substrate / photo-alignment film / polarizer was obtained in the same manner as in Example 1. Similar to Example 1, it was confirmed that it had polarization performance, and the laminated state was evaluated. The results are shown in Table 1.

[0135] 5. Example 5 A substrate obtained by subjecting the surface of a convex glass lens (SLB-30-70P manufactured by OptoSigma) to corona treatment (AGF-B10 manufactured by Kasuga Electric Co., Ltd.) was used as the curved substrate, and a polarizing plate composed of a curved substrate / photo-alignment film / polarizer was obtained in the same manner as in Example 1. Similar to Example 1, it was confirmed that it had polarization performance, and the laminated state was evaluated. The results are shown in Table 1.

[0136] 6. Example 6 A substrate obtained by subjecting the surface of a glass convex lens (SLB-30-200P manufactured by OptoSigma Corporation) to corona treatment (AGF-B10 manufactured by Kasuga Electric Co., Ltd.) was used as the curved substrate, and a polarizing plate composed of a curved substrate / photo-aligned film / polarizer was obtained in the same manner as in Example 1. Similar to Example 1, it was confirmed that it had polarization performance and the laminated state was evaluated. The results are shown in Table 1.

[0137] 7. Comparative Example 1 (1) Manufacture of iodine PVA type polarizing plate A polyvinyl alcohol film with a thickness of 30 μm (average degree of polymerization of about 2400, saponification degree of 99.9 mol% or more) was uniaxially stretched about 5 times by dry stretching, and then immersed in pure water at 40 ° C for 40 seconds while maintaining the tension state. Thereafter, it was immersed in a dyeing aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.044 / 5.7 / 100 at 28 ° C for 30 seconds for dyeing treatment. Next, it was immersed in a boric acid aqueous solution having a mass ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100 at 70 ° C for 120 seconds. Subsequently, after washing with pure water at 8 ° C for 15 seconds, it was dried at 60 ° C for 50 seconds and then at 75 ° C for 20 seconds while being held at a tension of 300 N to obtain a polarizer with a thickness of 12 μm in which iodine was adsorbed and oriented on the polyvinyl alcohol film. An aqueous adhesive was injected between the obtained polarizer and a cycloolefin film (ZF14 manufactured by Nippon Zeon Co., Ltd.) and laminated with a nip roll. While maintaining the tension of the obtained laminate at 430 N / m, it was dried at 60 ° C for 2 minutes to obtain an iodine PVA type polarizer having a cycloolefin film as a protective film on one side. The above aqueous adhesive was prepared by adding 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318; manufactured by Kuraray Co., Ltd.) and 1.5 parts of water-soluble polyamide epoxy resin (Sumirez Resin 650; manufactured by Sumika Chemtex Corporation, aqueous solution with a solid content concentration of 30%) to 100 parts of water.

[0138] A polarizing plate composed of a curved substrate / an adhesive layer / an iodine PVA-type polarizer was obtained in the same manner as in Example 3, except that the above iodine PVA-type polarizing plate and the curved substrate used in Example 3 were bonded with an adhesive (25 μm) manufactured by Lintec Corporation. Similar to Example 1, it was confirmed that it had polarization performance, and the laminated state was evaluated. The results are shown in Table 1.

[0139] 8. Comparative Example 2 A 2 mass% aqueous solution (composition for forming an alignment film) of polyvinyl alcohol (fully saponified type of polyvinyl alcohol 1000, manufactured by Wako Pure Chemical Industries, Ltd.) was applied onto the curved substrate used in Example 3 by spin coating. After drying, a coating film with a thickness of 100 nm was formed. Subsequently, an attempt was made to create an alignment film by performing the following rubbing treatment on the surface of the obtained coating film, but the rubbing treatment could not be sufficiently performed due to the shape of the curved substrate. The rubbing treatment was carried out using a semi-automatic rubbing apparatus (product name: LQ-008 type, manufactured by Shoyo Kogyo Co., Ltd.) with a cloth (product name: YA-20-RW, manufactured by Yoshikawa Chemical Industry Co., Ltd.) under the conditions of a pushing-in amount of 0.15 mm, a rotation speed of 500 rpm, and 16.7 mm / s.

[0140] A polarizing plate composed of a curved substrate / rubbing alignment film / polarizer was obtained by applying a composition for forming a polarizer in the same manner as in Example 1 onto the rubbing alignment film obtained by the above rubbing treatment, followed by drying and polymerization. When the polarization performance was confirmed in the same manner as in Example 1, it did not have polarization performance. Also, the laminated state was evaluated. The results are shown in Table 1.

[0141]

Table 1

Claims

An elliptical polarizing plate comprising a curved substrate made of a glass substrate, an optical alignment film, and a polarizer in this order, and a retardation layer having a quarter-wave plate function, wherein: Formula (1): 20 mm ≤ R ≤ 300 mm (1) [In formula (1), R represents the radius of curvature of the portion of the polarizing plate having the smallest curvature.] is satisfied, the polarizer is composed of a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye, the polymerizable liquid crystal compound is aligned so that the absorption axis of the polarizer is oriented in one direction with respect to the surface direction of the curved surface of the curved substrate on which the polarizer is laminated, an elliptical polarizing plate not including an adhesive layer between the polarizer and the retardation layer.

2. The elliptical polarizing plate according to claim 1, wherein the curved surface shape is a three-dimensional curved surface shape.

3. The elliptical polarizing plate according to claim 1 or 2, wherein the curved surface shape is lens-shaped.

4. The elliptical polarizing plate according to any one of claims 1 to 3, wherein the polarizer further contains a leveling agent.

5. The elliptical polarizing plate according to any one of claims 1 to 4, wherein the dichroic dye is an azo dye.

6. The elliptical polarizing plate according to any one of claims 1 to 5, wherein the polarizer exhibits a Bragg peak in X-ray analysis measurement.

7. (a) a step of forming an optical alignment film on a curved substrate made of a glass substrate, (b) a step of forming a coating film of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound and a dichroic dye on the optical alignment film, and (c) a step of forming a polarizer by phase-transitioning the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition to a smectic liquid crystal phase and then polymerizing the polymerizable liquid crystal compound while maintaining the smectic liquid crystal state, and a step of forming a retardation layer having a quarter-wave plate function is included, the polymerizable liquid crystal compound is aligned so that the absorption axis of the polarizer is oriented in one direction with respect to the surface direction of the curved surface of the curved substrate on which the polarizer is laminated, no adhesive layer is included between the polarizer and the retardation layer, Formula (1): 20 mm ≤ R ≤ 300 mm (1) [In formula (1), R represents the radius of curvature of the portion of the polarizing plate having the smallest curvature.] A method for manufacturing an elliptical polarizing plate having a curved surface shape, which satisfies the above conditions.

8. A flexible image display device having the elliptical polarizing plate according to any one of claims 1 to 6.

9. The flexible image display device according to claim 8, further comprising a window and a touch panel touch sensor.

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