KR20210049798A - Circular polarizing plate and image display device using the same - Google Patents

Abstract

A polarizing film and a retardation film functioning as a λ/4 plate are provided in this order, and the angle formed by the absorption axis of the polarizing film and the slow axis of the retardation film is 35° to 55°, and the retardation film contains a liquid crystal material. And, the retardation film satisfies the following equations (α) and (β), and Re(450)/Re(550)≤1.00 (α), 1.00≤Re(650)/Re(550) (β) the phase difference A circular polarizing plate in which the film contains foreign substances, the retardation film has a thickness of 1.5 μm or more, and the retardation film has a substantially flat surface.

Description

Circular polarizing plate and image display device using the same

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

BACKGROUND ART In recent years, the spread of mobile phones and tablet terminals has progressed, and a liquid crystal display device and an organic electroluminescent display device (organic EL display device) have been widely used as image display devices. In an organic EL display device, a circularly polarizing plate is disposed on the surface of the organic EL panel on the visible side in order to suppress external light from being reflected by a metal electrode (cathode) and being visually recognized like a mirror surface. In addition, the display device is required to be thinner in the market. Therefore, in a display device that is required to be thinner, it is preferable that each member such as a polarizing plate and a circularly polarizing plate used in the display device is also thin.

As the circularly polarizing plate, a laminate of a polarizing plate and a λ/4 plate is generally used. As a circularly polarizing plate, for example, it is known that a polarizing film and one retardation layer having a specific refractive index characteristic are laminated (see, for example, Patent Document 1).

The retardation film is generally a stretched film produced by stretching a resin film, but there is a limit to thinning in the λ/4 plate using this stretched film. Therefore, for further thinning, a λ/4 plate using a layer cured with a polymerizable liquid crystal compound has been proposed (see, for example, Patent Document 2). However, in the circularly polarizing plate with such a λ/4 plate, depending on the manufacturing process, foreign substances may be mixed, and this foreign substance (which was not a problem in the λ/4 plate composed of a resin film) becomes a bright spot. It may be discarded and adversely affect the display characteristics. In addition, there may be a problem that the manufacturing yield decreases. Such an influence is even greater in a circularly polarizing plate using a λ/4 plate using a layer obtained by curing a polymerizable liquid crystal compound having reverse wavelength dispersion with respect to a retardation value. This is because the antireflection effect can be obtained at a broader wavelength, so that the bright spot tends to be easily recognized.

[Patent Document 1] Japanese Patent No. 3325560 Publication [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-123134

The present invention has been made to solve the above conventional problems, the main object of which is to provide a circularly polarizing plate that is very thin, has excellent antireflection properties, and suppresses adverse effects on the display performance of an image display device caused by foreign substances. In having to.

That is, the present invention provides the following circularly polarizing plate and image display device.

[1] a polarizing film and a retardation film functioning as a λ/4 plate are provided in this order, and the angle formed by the absorption axis of the polarizing film and the slow axis of the retardation film is 35° to 55°,

The retardation film includes a liquid crystal material,

The retardation film satisfies the following formulas (α) and (β),

Re(450)/Re(550)≤1.00 (α)

1.00≤Re(650)/Re(550) (β)

The retardation film contains foreign substances,

The retardation film has a thickness of 1.5 μm or more,

A circularly polarizing plate having a substantially flat surface of the retardation film.

[In the formula, Re(450) represents an in-plane retardation value at a wavelength of 450 nm, Re(550) represents an in-plane retardation value at a wavelength of 550 nm, and Re (650) is an in-plane retardation value at a wavelength of 650 nm. Represents the phase difference value.]

[2] The circular polarizing plate according to [1], wherein the foreign material is a rubbing residue.

[3] A laminate comprising the circularly polarizing plate according to [1] or [2] and a touch sensor.

[4] An image display device having the circularly polarizing plate according to [1] or [2].

[5] An image display device having the laminate according to [3].

[6] The image display device according to [4] or [5], wherein the image display device is an organic electroluminescent display device.

Advantageous Effects of Invention According to the present invention, it is possible to obtain a circularly polarizing plate that is very thin, has excellent antireflection properties, and has suppressed adverse effects on the display performance of an image display device caused by foreign substances.

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

(Definition of terms and symbols)

Definitions of terms and symbols in the present specification are as follows.

(1) refractive index (nx, ny, nz)

"Nx" is a refractive index in a direction in which the in-plane refractive index is maximum (ie, a slow axis direction), "ny" is a direction orthogonal to the slow axis in the plane, and "nz" is a refractive index in the thickness direction.

(2) In-plane phase difference value

The in-plane retardation value (Re(λ)) refers to the in-plane retardation value of the film at a temperature of 23°C and a wavelength of λ(nm). Re(λ) is calculated by Re(λ)=(nx-ny)×d when the film thickness is d(nm).

(3) The phase difference value in the thickness direction

The in-plane retardation value Rth(λ) refers to a retardation value in the thickness direction of the film at a temperature of 23°C and a wavelength of λ(nm). Rth(λ) is obtained by Rth(λ)=((nx+ny)/2-nz)×d when the film thickness is d(nm).

(Polarizing film)

The polarizing film is not particularly limited, and various things can be used. As a polarizing film, for example, a dichroic substance such as iodine or a dichroic dye is adsorbed to a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene/vinyl acetate copolymer-based partial saponification film. Then) polyene-based oriented films, such as a monoaxially stretched product, a polyvinyl alcohol dehydration treatment product, and a polyvinyl chloride dehydrochloric acid treatment product, etc. are mentioned. Among these, a polarizing film containing a polyvinyl alcohol-based film and a dichroic substance such as iodine is suitable. The film thickness of these polarizing films is not particularly limited, but is generally about 3 to 80 µm. As a polarizing film applied to a display device requiring thinning, the film thickness is preferably 15 µm or less.

As the polyvinyl alcohol-based film, one obtained by saponifying a polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. This polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can be used. In addition, the degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, and preferably about 1,500 to 5,000.

What formed a film of a polyvinyl alcohol-based resin is used as a raw film of a polarizing film. The method of forming a film of a polyvinyl alcohol-based resin can be formed by a known method. The film thickness of the original film of the polyvinyl alcohol-based resin is preferably about 5 to 35 µm, and more preferably 5 to 20 µm, considering that the thickness of the obtained polarizing film is 15 µm or less. When the film thickness of the original film exceeds 35 µm, it is necessary to increase the draw ratio when producing the polarizing film, and there is a tendency that the dimensional shrinkage of the obtained polarizing film is increased. On the other hand, when the film thickness of the raw film is less than 5 µm, the handling property during stretching is lowered, and problems such as cutting tend to occur during manufacture.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing of the dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Further, uniaxial stretching may be performed in a plurality of these steps. This boric acid treatment plays a role of crosslinking the dyed polyvinyl alcohol-based resin film.

In uniaxial stretching, it may be uniaxially stretched between rolls having different circumferential speeds, or uniaxially stretched using a hot roll. In addition, uniaxial stretching may be dry stretching performed in the air, or wet stretching performed in a state in which a polyvinyl alcohol-based resin film is swollen in a solvent (for example, water). The draw ratio is usually about 3 to 8 times.

As a method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye is adopted. As a dichroic dye, iodine or a dichroic dye is specifically used. In addition, it is preferable that the polyvinyl alcohol-based resin film is subjected to an immersion treatment in water before the dyeing treatment.

When iodine is used as the dichroic dye, a method of dyeing by immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by weight per 100 parts by weight of water. In addition, the content of potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40°C. In addition, the immersion time (dyeing time) in this aqueous solution is usually about 20 to 1,800 seconds.

On the other hand, when a dichroic dye is used as a dichroic dye, a method of dyeing by immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution is usually about 1×10 ^-4 to 10 parts by weight ^{per 100 parts by weight of water, preferably about 1×10 -3 to} 1 part by weight. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the dichroic dye aqueous solution used for dyeing is usually about 20 to 80°C. In addition, the immersion time (dyeing time) in this aqueous solution is usually about 10 to 1,800 seconds.

The boric acid treatment after dyeing with a dichroic dye can be performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid.

The amount of boric acid in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight per 100 parts by weight of water, preferably 5 to 12 parts by weight. When iodine is used as a dichroic dye, it is preferable that this boric acid-containing aqueous solution contains potassium iodide. The amount of potassium iodide in the aqueous solution containing boric acid is usually about 0.1 to 15 parts by weight, preferably about 5 to 12 parts by weight per 100 parts by weight of water. The immersion time in the aqueous solution containing boric acid is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50°C or higher, preferably 50 to 85°C, and more preferably 60 to 80°C.

The polyvinyl alcohol-based resin film after boric acid treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing a polyvinyl alcohol-based resin film treated with boric acid in water. The water temperature in the water washing treatment is usually about 5 to 40°C. In addition, the immersion time is usually about 1 to 120 seconds.

After washing with water, a drying treatment is performed and a polarizing film can be obtained. Drying treatment can be performed using a hot air dryer or a far-infrared heater. The drying treatment temperature is usually about 30 to 100°C, preferably 50 to 80°C. The drying treatment time is usually about 60 to 600 seconds, preferably 120 to 600 seconds.

The moisture content of the polarizing film is reduced to a practical level by drying treatment. The moisture content is usually 5 to 20% by weight, preferably 8 to 15% by weight. If the moisture content is less than 5% by weight, the flexibility of the polarizing film is lost, and the polarizing film may be damaged or broken after drying. In addition, when the moisture content exceeds 20% by weight, the thermal stability of the polarizing film may be inferior.

In addition, the stretching, dyeing, boric acid treatment, water washing step, and drying step of the polyvinyl alcohol-based resin film in the polarizing film manufacturing step may be performed according to, for example, a method described in Japanese Patent Laid-Open No. 2012-159778. In the method described in this document, a polyvinyl alcohol-based resin layer serving as a polarizing film is formed by coating a polyvinyl alcohol-based resin on a base film.

As described above, the thickness of the polarizing film is preferably 15 µm or less, more preferably 3 to 10 µm.

Moreover, the said polarizing film can be used as a single-sided protective polarizing plate which has a protective film only on one side of this polarizing film, or a double-sided protective polarizing plate which has a protective film on both sides of a polarizing film.

The polarizing film may be a liquid crystal coating type polarizing film obtained by applying a composition containing a liquid crystal compound. The composition including the liquid crystal compound may include a liquid crystal compound and a dichroic dye. As a liquid crystal compound, what is necessary is just to have the property which shows a liquid crystal state, and especially what has a high order alignment state, such as a smectic phase, can exhibit high polarization performance, and is preferable. In addition, it is also preferable that the liquid crystal compound has a polymerizable functional group. The dichroic dye is a dye that is oriented together with a liquid crystal compound to exhibit dichroism, and the dichroic dye itself may have liquid crystal properties or may have a polymerizable functional group. Any one compound in the composition containing the liquid crystal compound has a polymerizable functional group. The composition comprising the liquid crystal compound may also contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. A liquid crystal coating type polarizing film can be produced by applying and curing a composition containing a liquid crystal compound on an alignment film. The liquid crystal coating-type polarizing film can be formed to have a thin thickness compared to a film-type polarizing film (a polarizing film formed of a polyvinyl alcohol-based resin film). The thickness of the liquid crystal coated polarizing film may be 0.5 to 5 µm, preferably 1 to 4 µm.

(Protective film)

As a material for forming a protective film formed on one or both sides of the polarizing film, those excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropic properties, and the like are preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polystyrene or acrylonitrile-styrene copolymer (AS resin) ), such as styrene-based polymers and polycarbonate-based polymers. In addition, polyethylene, polypropylene, polyolefin having a cyclo- or norbornene structure, polyolefin-based polymer such as ethylene-propylene copolymer, vinyl chloride-based polymer, amide-based polymer such as nylon or aromatic polyamide, imide-based polymer, alcohol Pone polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, Epoxy polymers, blends of the polymers, and the like are also exemplified as examples of polymers forming the protective film. The protective film can also be formed as a cured layer of thermosetting, ultraviolet-curable resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone. When a protective film is formed on both sides of a polarizing film, a protective film made of the same polymer material may be used at the front and back, or a protective film made of another polymer material or the like may be used.

The thickness of the protective film is generally about 1 to 100 µm in terms of workability such as strength and handling properties, and thin film properties. It is preferably 5 to 80 µm, more preferably 5 to 50 µm.

The polarizing film and the protective film are usually laminated through a water-based adhesive or the like. Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based, water-based polyurethane, and water-based polyesters. In addition to the above, examples of the adhesive between the polarizing film and the protective film include an ultraviolet curing adhesive and an electron beam curing adhesive. The electron beam-curable adhesive exhibits suitable adhesion to the various protective films. The protective film and the polarizing film are preferably subjected to saponification treatment, corona treatment, plasma treatment, and the like prior to bonding with the polarizing film.

The surface of the protective film on which the polarizing film is not adhered may be treated with a hard coat layer or an antireflection treatment, an antistatic layer or an antisticking layer, and a treatment for the purpose of diffusion or antiglare.

The protective film used on the side where the retardation film in the polarizing film is not laminated is provided with a treatment (typically circularly polarized light (or elliptically polarized light)) that improves visibility when visually recognized through polarized sunglasses, if necessary. Or imparting an ultra-high phase difference) may be implemented. By performing such a treatment, even when the display screen is visually recognized through a polarized lens such as polarized sunglasses, excellent visibility can be realized. Therefore, the circularly polarizing plate can be suitably applied to an image display device that can be used outdoors.

Moreover, it is preferable that the protective film used between a polarizing film and a retardation film is optically isotropic. In the present specification, "optically isotropic" means that Re(550) is 0 nm to 10 nm, and Rth(550) is -20 nm to +20 nm.

(A retardation film functioning as a λ/4 plate)

The retardation film containing the liquid crystal material used in the present invention can function as a so-called λ/4 plate. The in-plane retardation value Re(550) at a wavelength of 550 nm of the retardation film is 90 to 190 nm, preferably 110 to 170 nm, more preferably 120 to 160 nm.

The retardation film includes a liquid crystal material. Including a liquid crystal material is a concept including a liquid crystal material capable of forming a liquid crystal layer, or a cured product obtained by using a liquid crystal material and cured by polymerization reaction or the like in which the liquid crystal material is in a liquid crystal state. By using a liquid crystal material, the difference between nx and ny of the obtained retardation layer can be significantly increased compared to that of a non-liquid crystal material. As a result, the thickness of the retardation layer for obtaining a desired in-plane retardation value can be significantly reduced, and thus, it is possible to contribute to thinning of the resulting circularly polarizing plate and image display device. In addition, roll-to-roll is possible in the manufacture of the circularly polarizing plate, so that the manufacturing process can be significantly shortened. Details will be described later.

It is preferable that the liquid crystal material can form (nematic liquid crystal) in which the liquid crystal phase is a nematic phase. The liquid crystal expression mechanism of the liquid crystal material may be lyotropic or thermotropic. The alignment state of the liquid crystal material is preferably homogeneous alignment. As a liquid crystal material, it may be used independently and may be used combining multiple types.

The phase difference film is preferably a cured layer of a liquid crystal material. Specifically, it is preferable that the liquid crystal material is a polymerizable monomer and/or a crosslinkable monomer. The liquid crystal material of this polymerizable monomer or crosslinkable monomer is sometimes referred to as "polymerizable liquid crystal" below. The polymerizable liquid crystal can be fixed by polymerizing or crosslinking the polymerizable liquid crystal. After aligning the polymerizable liquid crystal, for example, by polymerizing or crosslinking the polymerizable liquid crystal, the alignment state can be fixed thereby. Here, a polymer is formed by polymerization, and a three-dimensional mesh structure is formed by crosslinking, which are non-liquid crystalline. Therefore, the formed retardation film does not cause a transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change peculiar to a liquid crystal compound such as a polymerizable liquid crystal. The retardation film obtained as a result can be a layer having very excellent stability that is not affected by temperature changes.

In order for the layer formed by polymerizing the polymerizable liquid crystal to exhibit an in-plane retardation, the polymerizable liquid crystal may be aligned in an appropriate direction. When the polymerizable liquid crystal is in a rod shape, an in-plane retardation is expressed by horizontally aligning the optical axis of the polymerizable liquid crystal with respect to the plane of the substrate. In this case, the optical axis direction and the slow axis direction coincide. When the polymerizable liquid crystal is disk-shaped, an in-plane retardation is expressed by horizontally aligning the optical axis of the polymerizable liquid crystal with respect to the plane of the substrate. In this case, the optical axis and the slow axis are orthogonal. The alignment state of a polymerizable liquid crystal can be adjusted by a combination of this alignment film and a polymerizable liquid crystal using an appropriate alignment film.

In the present invention, a retardation film having optical properties represented by formulas (α) and (β) can be obtained by using the cured layer of the polymerizable liquid crystal described below. In order to express such optical properties, two or more retardation films may be laminated to form a retardation film of the circularly polarizing plate of the present invention. In the case of using two or more retardation films, one or more of them should just contain a liquid crystal material.

Re(450)/Re(550)≤1.00 (α)

1.00≤Re(650)/Re(550) (β)

Re(450)/Re(550) is preferably 0.95 or less, and may be 0.90 or less. It is preferable that Re(650)/Re(550) exceed 1.00.

<Polymerizable liquid crystal>

As described above, the polymerizable liquid crystal is a liquid crystal material having a polymerizable group. The polymerizable group means a group involved in a polymerization reaction, and a photopolymerizable group is preferable. Here, the photopolymerizable group refers to a group that can participate in the polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described later. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, and the like. . Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The liquid crystallinity of the polymerizable liquid crystal may be a thermotropic liquid crystal or a lyotropic liquid crystal. When the thermotropic liquid crystal is classified by order, nematic liquid crystal or smectic liquid crystal may be used.

For example, the polymerizable liquid crystal used in the present invention is a compound represented by the following formula (1) (hereinafter sometimes referred to as "compound (1)"), since it can exhibit desirable optical properties.

P ¹ -F ¹ -(B ¹ -A ¹ ) _k -E ¹ -G ¹ -D ¹ -Ar-D ² -G ² -E ² -(A ² -B ² ) _l -F ² -P ² ( One)

[In formula (1), Ar represents a divalent group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle, and among Ar groups, the number of π electrons included in the aromatic ring N _π is 12 That's it.

D ¹ and D ² are each independently *-O-CO- (* indicates a position bonded to Ar), *-C(=S)-O-, *-OC(=S)-, *-CR ¹ R ² -, *-CR ¹ R ² -CR ³ R ⁴ -, *-O-CR ¹ R ² -, * ^{-CR 1} R ² -O-, *-CR ¹ R ² -O-CR ³ R ⁴ -, *-CR ¹ R ² -O-CO-, *-O-CO-CR ¹ R ² -, *-CR ¹ R ² -O-CO-R ³ R ⁴ -, *-CR ¹ R ² -CO-O-CR ³ R ⁴ -, *-NR ¹ -CR ² R ³ -, *-CR ² R ³ -NR ¹ -, *-CO-NR ¹ -or *-NR ¹ -CO- . R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 4 carbon atoms.

Each of G ¹ and G ² independently represents a divalent alicyclic hydrocarbon group. The hydrogen atom contained in this 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. The methylene group contained in the formula hydrocarbon group may be substituted with -O-, -S-, or -NH-.

E ¹ , E ² , B ¹ and B ² are each independently -CR ⁵ R ⁶ -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ⁵ -, -NR ⁵ -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond. R ⁵ and R ⁶ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 4 carbon atoms.

A ¹ and A ² each independently represent a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group. The hydrogen atom contained in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group. The hydrogen atom contained in the C1-C4 alkyl group and the C1-C4 alkoxy group may be substituted with a fluorine atom.

k and l each independently represent the integer of 0-3.

Each of F ¹ and F ² independently represents an alkylene group having 1 to 12 carbon atoms. The hydrogen atom contained in this alkylene group may be substituted with an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom, and the methylene group contained in the alkylene group is substituted with -O- or -CO- You may have it.

P ¹ and P ² each independently represent a hydrogen atom or a polymerizable group (however, ^{at least one of P 1} and P ² represents a polymerizable group).

It is preferable that compound (1) meets the requirements represented by formula (2) and formula (3).

(N _π -4)/3<k+l+4 (2)

12≤N _π ≤22 (3)

[In formulas (2) and (3), N _π , k and l represent the same meaning as described above.]

Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthroline ring. Examples of the aromatic heterocycle include a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, and a benzothiazole ring. Among these, a benzene ring, a thiazole ring, and a benzothiazole ring are preferable.

Ar is a divalent group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle, and the total number of π electrons of the aromatic ring contained in the divalent group N _π is 12 or more, preferably Is 12 or more and 22 or less, and more preferably 13 or more and 22 or less.

Ar is preferably a divalent group having at least two aromatic rings selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocycle.

In formula (1), it is preferable that Ar is any divalent group represented by formulas (Ar-1) to (Ar-13).

[In formulas (Ar-1) to (Ar-13), Z ¹ is a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 6 carbon atoms, and an alkyl having 1 to 6 carbon atoms. Sulfonyl group, carboxyl group, C1-C6 fluoroalkyl group, C1-C6 alkoxy group, C1-C6 alkylthio group, C1-C6 N-alkylamino group, C2-C12 N,N- A dialkylamino group, a C1-C6 N-alkylsulfamoyl group, or a C2-C12 N,N-dialkylsulfamoyl group is shown.

Q ¹ and Q ³ each independently represent -CR ⁷ R ⁸ -, -S-, -NR ⁷ -, -CO- or -O-.

R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Y ¹ , Y ² and Y ³ each independently represent an optionally substituted aromatic hydrocarbon group or an aromatic heterocyclic group.

Each of W ¹ and W ² independently represents a hydrogen atom, a cyano group, a methyl group, or a halogen atom.

m represents the integer of 0-6.

n represents the integer of 0-2.]

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among them, a fluorine atom, a chlorine atom, and a bromine atom are preferable.

Examples of the C1-C6 alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. Among these, a C1-C4 alkyl group is preferable, a C1-C2 alkyl group is more preferable, and a methyl group is especially preferable.

Examples of the alkylsulfinyl group having 1 to 6 carbon atoms include methylsulfinyl group, ethylsulfinyl group, propylsulfinyl group, isopropylsulfinyl group, butylsulfinyl group, isobutylsulfinyl group, sec-butylsulfinyl group, tert-butylsulfinyl group, and pentylsulfinyl group. And a nil group and a hexylsulfinyl group. Among them, an alkylsulfinyl group having 1 to 4 carbon atoms is preferable, an alkylsulfinyl group having 1 to 2 carbon atoms is more preferable, and a methylsulfinyl group is particularly preferable.

Examples of the alkylsulfonyl group having 1 to 6 carbon atoms include methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, isopropylsulfonyl group, butylsulfonyl group, isobutylsulfonyl group, sec-butylsulfonyl group, tert-butylsulfonyl group, and pentylsulfonyl group. A nil group, a hexylsulfonyl group, etc. are mentioned. Among them, an alkylsulfonyl group having 1 to 4 carbon atoms is preferable, an alkylsulfonyl group having 1 to 2 carbon atoms is more preferable, and a methylsulfonyl group is particularly preferable.

Examples of the fluoroalkyl group having 1 to 6 carbon atoms include a fluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a pentafluoroethyl group, a heptafluoropropyl group, and a nonafluorobutyl group. Among them, a fluoroalkyl group having 1 to 4 carbon atoms is preferable, a fluoroalkyl group having 1 to 2 carbon atoms is more preferable, and a trifluoromethyl group is particularly preferable.

Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, pentyloxy group, hexyloxy group, etc. Can be lifted. Especially, a C1-C4 alkoxy group is preferable, a C1-C2 alkoxy group is more preferable, and a methoxy group is especially preferable.

Examples of the C1-C6 alkylthio group include methylthio group, ethylthio group, propylthio group, isopropylthio group, butylthio group, isobutylthio group, sec-butylthio group, tert-butylthio group, and pentylthio group. Ogi, a hexylthio group, etc. are mentioned. Especially, a C1-C4 alkylthio group is preferable, a C1-C2 alkylthio group is more preferable, and a methylthio group is especially preferable.

Examples of the N-alkylamino group having 1 to 6 carbon atoms include N-methylamino group, N-ethylamino group, N-propylamino group, N-isopropylamino group, N-butylamino group, N-isobutylamino group, N-sec-butylamino group, N-tert-butylamino group, N-pentylamino group, N-hexylamino group, etc. are mentioned. Among these, an N-alkylamino group having 1 to 4 carbon atoms is preferable, an N-alkylamino group having 1 to 2 carbon atoms is more preferable, and an N-methylamino group is particularly preferable.

Examples of the N,N-dialkylamino group having 2 to 12 carbon atoms include N,N-dimethylamino group, N-methyl-N-ethylamino group, N,N-diethylamino group, N,N-dipropylamino group, N,N- Diisopropylamino group, N,N-dibutylamino group, N,N-diisobutylamino group, N,N-dipentylamino group, N,N-dihexylamino group, etc. are mentioned. Among these, an N,N-dialkylamino group having 2 to 8 carbon atoms is preferable, an N,N-dialkylamino group having 2 to 4 carbon atoms is more preferable, and an N,N-dimethylamino group is particularly preferable.

Examples of the N-alkylsulfamoyl group having 1 to 6 carbon atoms include N-methylsulfamoyl group, N-ethylsulfamoyl group, N-propylsulfamoyl group, N-isopropylsulfamoyl group, N-butylsulfamoyl group, N -Isobutylsulfamoyl group, N-sec-butylsulfamoyl group, N-tert-butylsulfamoyl group, N-pentylsulfamoyl group, N-hexylsulfamoyl group, etc. are mentioned. Among these, an N-alkylsulfamoyl group having 1 to 4 carbon atoms is preferable, an N-alkylsulfamoyl group having 1 to 2 carbon atoms is more preferable, and an N-methylsulfamoyl group is particularly preferable.

As a C2-C12 N,N-dialkylsulfamoyl group, N,N-dimethylsulfamoyl group, N-methyl-N-ethylsulfamoyl group, N,N-diethylsulfamoyl group, N,N- Dipropylsulfamoyl group, N,N-diisopropylsulfamoyl group, N,N-dibutylsulfamoyl group, N,N-diisobutylsulfamoyl group, N,N-dipentylsulfamoyl group, N,N -Dihexylsulfamoyl group, etc. are mentioned. Among them, a C2-C8 N,N-dialkylsulfamoyl group is preferable, a C2-C4 N,N-dialkylsulfamoyl group is more preferable, and a N,N-dimethylsulfamoyl group is particularly preferable. Do.

Z ¹ is a halogen atom, methyl group, cyano group, nitro group, carboxyl group, methylsulfonyl group, trifluoromethyl group, methoxy group, methylthio group, N-methylamino group, N,N-dimethylamino group, N-methylsulfamoyl group Or it is preferably an N,N-dimethylsulfamoyl group.

Examples of the alkyl group having 1 to 4 carbon atoms for R ⁷ and R ⁸ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group. Among them, an alkyl group having 1 to 2 carbon atoms is preferable, and a methyl group is more preferable.

It is preferable that Q ¹ is -S-, -CO-, -NH-, -N(CH ₃ )-, and it is preferable that Q ³ is -S-, -CO-.

Examples of the aromatic hydrocarbon group for Y ¹ , Y ² and Y ³ include an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group. Among them, a phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable. The aromatic heterocyclic group includes at least one hetero atom such as a nitrogen atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group, an oxygen atom, and a sulfur atom, and has 4 to 20 carbon atoms. And aromatic heterocyclic groups of, and a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, and a thiazolyl group are preferable.

Such an aromatic hydrocarbon group and an aromatic heterocyclic group may have at least one substituent, and examples of the substituent include a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 6 carbon atoms, and a 1 to 6 carbon atom. Alkylsulfonyl group, carboxyl group, C1-C6 fluoroalkyl group, C1-C6 alkoxy group, C1-C6 alkylthio group, C1-C6 N-alkylamino group, C2-C12 N, An N-dialkylamino group, a C1-C6 N-alkylsulfamoyl group, a C2-C12 N,N-dialkylsulfamoyl group, etc. are mentioned. Among them, halogen atom, C1-C2 alkyl group, cyano group, nitro group, C1-C2 alkylsulfonyl group, C1-C2 fluoroalkyl group, C1-C2 alkoxy group, C1-C2 alkyl Thio group, a C1-C2 N-alkylamino group, a C2-C4 N,N-dialkylamino group, and a C1-C2 alkylsulfamoyl group are preferable.

Halogen atom, C1-C6 alkyl group, cyano group, nitro group, C1-C6 alkylsulfinyl group, C1-C6 alkylsulfonyl group, carboxyl group, C1-C6 fluoroalkyl group, C1-C6 An alkoxy group, a C1-C6 alkylthio group, a C1-C6 N-alkylamino group, a C2-C12 N,N-dialkylamino group, a C1-C6 N-alkylsulfamoyl group, and a C2-C2 group Examples of the 12 N,N-dialkylsulfamoyl group include those described above.

It is preferable that Y ¹ , Y ² and Y ³ are each independently a group represented by formula (Y-1) to formula (Y-6).

[In formulas (Y-1) to (Y-6), Z ² is a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 6 carbon atoms, and an alkyl having 1 to 6 carbon atoms. Sulfonyl group, carboxyl group, C1-C6 fluoroalkyl group, C1-C6 alkoxy group, C1-C6 thioalkyl group, C1-C6 N-alkylamino group, C2-C12 N,N-di An alkylamino group, a C1-C6 N-alkylsulfamoyl group, or a C2-C12 N,N-dialkylsulfamoyl group is shown.

a ¹ is an integer of 0 to 5, a ² is an integer of 0 to 4, b ¹ is an integer of 0 to 3, b ² is an integer of 0 to 2, and R represents a hydrogen atom or a methyl group.]

As Z ² , a halogen atom, a methyl group, a cyano group, a nitro group, a sulfone group, a carboxyl group, a trifluoromethyl group, a methoxy group, a thiomethyl group, an N,N-dimethylamino group or an N-methylamino group is preferable.

In addition, ^{it is particularly preferable that Y 1} , Y ² and Y ³ are each independently a group represented by the formula (Y-1) or (Y-3) from the viewpoint of the manufacturing process and cost of the compound (1).

It is preferable that W ¹ and W ² are each independently a hydrogen atom, a cyano group, or a methyl group, and particularly preferably a hydrogen atom.

It is preferable that m is 0 or 1. It is preferable that n is 0.

In formula (1), Ar is preferably a group represented by formula (Ar-6), and among them, formula (Ar-6a), formula (Ar-6b), formula (Ar-6c), formula (Ar-10a) Or it is more preferable that it is a divalent group represented by (Ar-10b).

[In formulas (Ar-6a) to (Ar-6c), formulas (Ar-10a) and formulas (Ar-10b), Z ¹ , n, Q ¹ , Z ² , a ¹ and b ¹ are as described above Show meaning.]

Examples of Ar are shown in formulas (ar-1) to (ar-189).

Specific examples of the groups represented by formulas (Ar-1) to (Ar-4) include groups represented by formulas (ar-1) to (ar-29).

Specific examples of the group represented by formula (Ar-5) include groups represented by formulas (ar-30) to (ar-39).

As specific examples of the group represented by the formula (Ar-6) or the formula (Ar-7), groups represented by the formulas (ar-40) to (ar-119) can be mentioned.

Specific examples of the group represented by the formula (Ar-8) or (Ar-9) include groups represented by the formulas (ar-120) to (ar-129).

Specific examples of the group represented by formula (Ar-10) include groups represented by formulas (ar-130) to (ar-149).

Specific examples of the group represented by the formula (Ar-11) include groups represented by the formulas (ar-150) to (ar-159).

Specific examples of the group represented by formula (Ar-12) include groups represented by formulas (ar-160) to (ar-179).

Specific examples of the group represented by the formula (Ar-13) include groups represented by the formulas (ar-180) to (ar-189).

D ¹ and D ² are *-O-CO-, *-OC(=S)-, *-O-CR ¹ R ² -, *-NR ¹ -CR ² R ³ -or *-NR ¹ -CO- (* represents a bonding site with Ar.) It is preferable that it is. It is more preferable that D ¹ and D ² are *-O-CO-, *-OC(=S)- or *-NR ¹ -CO- (* represents a binding site to Ar.). R ¹ , R ² , R ³ and R ⁴ are each independently preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group.

As G ¹ and G ² , an alicyclic hydrocarbon group which may contain a hetero atom represented by formulas (g-1) to (g-10) is exemplified, and it is preferably a 5- or 6-membered alicyclic hydrocarbon group. Do.

Groups represented by the above formulas (g-1) to (g-10) include alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, isopropyl group, and tert-butyl group; Alkoxy groups having 1 to 4 carbon atoms such as a methoxy group and an ethoxy group; Fluoroalkyl groups having 1 to 4 carbon atoms such as trifluoromethyl groups; A fluoroalkoxy group having 1 to 4 carbon atoms such as a trifluoromethoxy group; Cyano group; Nitro group; It may be substituted with a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom.

As G ¹ and G ² , it is preferably an alicyclic hydrocarbon group containing a 6-membered ring represented by the formula (g-1), more preferably a 1,4-cyclohexylene group, and a trans-1,4-cyclohexyl group. It is particularly preferred that it is a silene group.

As the ^{divalent alicyclic hydrocarbon group or aromatic hydrocarbon group in A 1} and A ² , an alicyclic hydrocarbon group including a 5- or 6-membered ring represented by the above formulas (g-1) to (g-10), or And a divalent aromatic hydrocarbon group having about 6 to 20 carbon atoms represented by formulas (a-1) to (a-8).

Further, as A ¹ and A ² , some of the hydrogen atoms of the above-exemplified groups are alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, i-propyl group or t-butyl group; Alkoxy groups having 1 to 4 carbon atoms such as a methoxy group or an ethoxy group; Trifluoromethyl group; Trifluoromethyloxy group; Cyano group; Nitro group; It may be substituted with a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom.

As A ¹ and A ² , especially if both groups are of the same type, since the preparation of compound (1) is easy, it is preferable. In addition, as A ¹ and A ² , a monocyclic 1,4-phenylene group or 1,4-cyclohexylene group is preferable, and since preparation of compound (1) is easy, a 1,4-phenylene group is particularly preferable. .

If B ¹ and B ² are divalent groups of the same kind, since the preparation of compound (1) is easy, it is preferable. Furthermore, the compounds (1) so prepared is more easily, B ¹ and B ² of, A ¹ and A ² and are each coupled to only B ¹ and B ² are independently -CH ₂ -CH ₂ in the -, -CO- O-, -O-CO-, -CO-NH-, -NH-CO-, -O-CH ₂ -, -CH ₂ -O- or a single bond is preferable, and particularly, since it shows high liquid crystallinity- CO-O- or -O-CO- is preferred. B ¹ and B of the ^2, E ¹ or E ^2, B ¹ and B ² are bonded with each independently -O-, -CO-O-, -O- CO-, -O-CO-O-, - It is more preferable that it is CO-NH-, -NH-CO- or a single bond.

It is preferable that k and l each independently represent an integer of 0 to 3 from the viewpoint of liquid crystallinity, and it is more preferable that k and l are 0 to 2. The sum of k and l is preferably 5 or less, and more preferably 4 or less.

Each of P ¹ and P ² independently represents a hydrogen atom or a polymerizable group (however, ^{at least one of P 1} and P ² represents a polymerizable group). When both P ¹ and P ² are polymerizable groups, since the film hardness of the obtained retardation film tends to be excellent, it is preferable.

The polymerizable group is a substituent capable of polymerizing the compound (1) of the present invention, and specifically, a vinyl group, a p-stilbene group, an acryloyl group, a methacroyl group, an acryloyloxy group, a methacroyloxy group, a carboxyl group, A methylcarbonyl group, a hydroxyl group, an amide group, an alkylamino group having 1 to 4 carbon atoms, an amino group, an epoxy group, an oxetanyl group, an aldehyde group, an isocyanate group or a thioisocyanate group, and the like are exemplified. In addition, the polymerizable group may contain groups represented as ^{B 1} and B ² in order to bond the ^{above-exemplified groups with E 1} and E ^2. For example, a radical polymerizable or cationic polymerizable group suitable for photopolymerization is preferred, and since it is particularly easy to handle and manufacture is also easy, an acryloyl group or a methacroyl group is preferred, and an acryloyl group is more preferred. When both P ¹ and P ² are polymerizable groups, since the film hardness of the obtained retardation film tends to be excellent, it is more preferable.

-D ¹ -G ¹ -E ¹ -(A ¹ -B ¹ ) _k -F ¹ -P ¹ , -D ² -G ² -E ² -(A ² -B ² ) _l -F ² -P ² Examples include groups represented by formulas (R-1) to (R-134). * (Asterisk) indicates the bonding position with Ar. In addition, n in Formulas (R-1) to (R-134) represents an integer of 2 to 12.

Moreover, as compound (1), compound (i)-compound (xxxiv) are mentioned. In the table, R1 is -D ¹ -G ¹ -E ¹ -(A ¹ -B ¹ ) _k -F ¹ -P ¹ , and R2 is -D ² -G ² -E ² -(A ² -B ² ) ₁ -F ² -P ² is represented.

In addition, in the compound (xxx) and the compound (xxxi), either of R1 and R2 is any one of (R-57) to (R-120).

In Table 1, the compound (xvii) is a group represented by Ar, a group represented by formula (ar-78), a group represented by Ar, a group represented by formula (ar-79), or a group represented by Ar It means any one of a mixture of a group compound represented by formula (ar-78) and a group compound represented by formula (ar-79).

In Table 2, the compound (xxx) is a group represented by Ar, a group represented by the formula (ar-120), a group represented by Ar, a group represented by the formula (ar-121), or a group represented by Ar It means any one of a mixture of a group compound represented by the formula (ar-120) and a group compound represented by the formula (ar-121), and the compound (xxxi) is a group represented by the formula (ar-122) The group represented by the compound, the group represented by Ar is a group represented by the formula (ar-123), or the group represented by Ar is represented by the formula (ar-122) and the group represented by the formula (ar-123) It means any one of a mixture of compounds.

In addition, typical structural formulas of the compounds shown in Table 1 are illustrated below. In the formation of the retardation film, a plurality of different types of compounds (1) may be used.

Further as the compound (1), for example, the following are exemplified. However, in the formula, n1 and n2 each independently represent the integer of 2-12.

Compound (1) is a known organic compound described in organic chemistry methods (Methoden der Organischen Chemie), Organic Reactions, Organic Syntheses, Comprehensive Organic Synthesis, and new experimental chemistry courses. Synthesis reaction (e.g., condensation reaction, esterification reaction, Williamson reaction, Ullman reaction, Wittich reaction, Sif base formation reaction, Benzylation reaction, Sonogashira reaction, Suzuki-Miyaura reaction, Negishi reaction, Kumada reaction, Hiyama reaction, Buchwald-Hartwig (Buchwald-Hartwig) reaction, Friedel-Crafts (Friedel-Crafts) reaction, Heck reaction, Aldol reaction, etc.) can be prepared by appropriately combining according to the structure.

For example, in the case of compound (1) wherein ^{D 1} and D ^{2 are *-O-CO-, formula (1-1)}

HO-Ar-OH (1-1)

(In the formula, Ar represents the same meaning as above.)

The compound represented by and formula (1-2)

(In the formula, G ¹ , E ¹ , A ¹ , B ¹ , F ¹ , P ¹ and k represent the same meaning as above.)

By reacting the compound represented by the formula (1-3)

(In the formula, Ar, G ¹ , E ¹ , A ¹ , B ¹ , F ¹ , P ¹ and k represent the same meaning as above.) A compound represented by the above can be obtained, and the obtained formula (1-3) Compounds and formulas represented by (1-4)

(In the formula, G ² , E ² , A ² , B ² , F ² , P ² and 1 have the same meaning as described above.) It can be produced by reacting a compound represented by.

The reaction of the compound represented by the formula (1-1) and the compound represented by the formula (1-2) and the reaction of the compound represented by the formula (1-3) and the compound represented by the formula (1-4) is an ester It is preferred to carry out in the presence of an agent.

As an esterifying agent (condensing agent), dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, 1-ethyl-3- (3-dimethylaminopropyl)carbodiimide hydrochloride, bis(2,6-diisopropylphenyl)carbodiimide, bis(trimethylsilyl)carbodiimide, bisisopropylcarbodiimide, 2,2'-carbonyl Bis-1H-imidazole is preferred.

The composition containing a polymerizable liquid crystal may contain, in addition to the compound represented by the formula (1), other liquid crystal compounds (however, it is different from the compound (1)).

It is preferable that other liquid crystal compounds also have a polymerizable group. As specific examples of other liquid crystal compounds, Chapter 3 Molecular Structure and Liquid Crystalline of the Liquid Crystal Handbook (Liquid Crystal Handbook Editing Committee edition, Maruzen Co., Ltd. issued on October 30, 2000), 3.2 non-chiral rod-shaped liquid crystal molecules, and 3.3 chiral membranes. Among the compounds described in large liquid crystal molecules, a compound having a polymerizable group is exemplified.

As the other liquid crystal compound, a plurality of other compounds may be used in combination.

Examples of other liquid crystal compounds include compounds represented by formula (4) (hereinafter sometimes referred to as "compound (4)") and the like.

P ¹¹ -E ¹¹ -(B ¹¹ -A ¹¹ ) _t -B ¹² -G (4)

[In formula (4), A ¹¹ represents an aromatic hydrocarbon group, an alicyclic hydrocarbon group or a heterocyclic group, and the hydrogen atom contained in the aromatic hydrocarbon group, the alicyclic hydrocarbon group and the heterocyclic group is a halogen atom, 1 to 6 carbon atoms, It may be substituted with an alkyl group, an alkoxy group having 1 to 6 carbon atoms, an alkylamino group having 1 to 6 carbon atoms, a nitro group, a nitrile group, or a mercapto group.

B ¹¹ and B ¹² are each independently -CR ¹⁴ R ¹⁵ -, -C≡C-, -CH=CH-, -CH ₂ -CH ₂ -, -O-, -S-, -CO-, -CO -O-, -O-CO-, -O-CO-O-, -C(=S)-, -C(=S)-O-, -OC(=S)-, -CH=N-, -N = CH-, -N = N-, -CO-NR 14 -, -NR 14 -CO-, -OCH 2 -, -OCF 2 -, -NR 14 -, -CH 2 O-, -CF 2 O-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond. R ¹⁴ and R ¹⁵ may each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 4 carbon atoms, and R ¹⁴ and R ¹⁵ may be connected to each other to form an alkylene group having 4 to 7 carbon atoms.

E ¹¹ represents an alkylene group having 1 to 12 carbon atoms. The hydrogen atom contained in this alkylene group may be substituted with a C1-C6 alkyl group, a C1-C6 alkoxy group, or a halogen atom.

P ¹¹ represents a polymerizable group.

G is a hydrogen atom, a halogen atom, a C1-C13 alkyl group, a C1-C13 alkoxy group, a C1-C13 fluoroalkyl group, a C1-C13 alkylamino group, a nitrile group, a nitro group, or a C1-C13 alkoxy group. It represents a polymerizable group bonded through a 12 alkylene group, and the hydrogen atom contained in the alkylene group may be substituted with an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

t represents the integer of 1-5.]

In particular, as ^{the polymerizable group in P 11} and G, any group capable of polymerizing with compound (1) may be used, and a vinyl group, a vinyloxy group, a p-stilbene group, an acryloyl group, an acryloyloxy group, a metachromyl group, Methacroyloxy group, carboxyl group, acetyl group, hydroxyl group, carbamoyl group, amino group, alkylamino group having 1 to 4 carbon atoms, epoxy group, oxetanyl group, formyl group, -N=C=O or N=C=S, etc. I can. Among them, from the viewpoint of being suitable for photopolymerization, a radical polymerizable group or a cationic polymerizable group is preferable, and from the viewpoint of easy handling and easy production of a liquid crystal compound, an acryloyloxy group, a metachromyloxy group, or a vinyloxy group Group is preferred.

In addition, ^{the number of carbon atoms of the aromatic hydrocarbon group, alicyclic hydrocarbon group and heterocyclic group of A 11} is, for example, 3 to 18, preferably 5 to 12, and particularly preferably 5 or 6.

Examples of the compound (4) include compounds represented by formulas (4-1) and (4-2).

P ¹¹ -E ¹¹ -(B ¹¹ -A ¹¹ ) _t1 -B ¹² -E ¹² -P ¹² (4-1)

P ¹¹ -E ¹¹ -(B ¹¹ -A ¹¹ ) _t2 -B ¹² -F ¹¹ (4-2)

[In formula (4-1) and formula (4-2), P ¹¹ , E ¹¹ , B ¹¹ , A ¹¹ and B ¹² have the same definition as above.

F ¹¹ represents a hydrogen atom, a halogen atom, a C1-C13 alkyl group, a C1-C13 alkoxy group, a C1-C13 fluoroalkyl group, a C1-C13 alkylamino group, a cyano group, or a nitro group.

E ¹² is synonymous with E ^11.

P ¹² is synonymous with P ^11.

t ¹ and t ² are synonymous with t.]

In addition, the compounds represented by formulas (4-1) and (4-2) include compounds represented by formulas (I), (II), (III), (IV), or (V). do.

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -A ¹³ -B ¹⁴ -A ¹⁴ -B ¹⁵ -A ¹⁵ -B ¹⁶ -E ¹² -P ¹² (I)

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -A ¹³ -B ¹⁴ -A ¹⁴ -B ¹⁵ -E ¹² -P ¹² (II)

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -A ¹³ -B ¹⁴ -E ¹² -P ¹² (III)

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -A ¹³ -B ¹⁴ -F ¹¹ (IV)

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -F ¹¹ (V)

[In formulas (I) to (V), A ^{12 to} A ¹⁵ are synonymous with A ^11, and B ^{13 to} B ¹⁶ are synonymous with B ¹¹ ].

In addition, in the compound represented by formula (4-1), formula (4-2), formula (I), formula (II), formula (III), formula (IV) and formula (V), P ¹¹ and By appropriately selecting the combination of E ¹¹ and by appropriately selecting the combination of P ¹² and E ¹² , it is preferable that both are bonded via an ether bond or an ester bond.

As a specific example of compound (4), the following formula (I-1)-formula (I-5), formula (II-1)-formula (II-6), formula (III-1)-formula (III-19) ), compounds represented by formulas (IV-1) to (IV-14), and formulas (V-1) to (V-5), and the like. However, in the formula, k represents the integer of 1-11. These liquid crystal compounds are preferable because they are easy to synthesize and are available on the market.

In the case of using other liquid crystal compounds, the amount used is, for example, 90 parts by weight or less based on 100 parts by weight of the total of the other liquid crystal compounds and compound (1).

It is preferable that the composition containing a polymerizable liquid crystal (hereinafter referred to as "liquid crystal composition") further contains a polymerization initiator. It is preferable that the polymerization initiator is a photopolymerization initiator. Examples of the photopolymerization initiator include benzoins, benzophenones, benzyl ketals, α-hydroxy ketones, α-amino ketones, iodonium salts or sulfonium salts, and more specifically, Irgacure 907 , Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369 (above, all manufactured by Chiba Specialty Chemicals), Sakeall BZ, Sakeall Z, Sakeall BEE (above , All manufactured by Seiko Chemical Co., Ltd.), Kayacure BP100 (manufactured by Nippon Kayaku Corporation), Kayacure UVI-6992 (manufactured by Dawoo Corporation), Adeka Optoma SP-152 or Adeka Optoma SP-170 (above, all manufactured by ADEKA Co., Ltd.), etc. are mentioned.

The amount of the polymerization initiator used is, for example, 0.1 parts by weight to 30 parts by weight, preferably 0.5 parts by weight to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. When the amount of the polymerization initiator is within the above range, compound (1) can be polymerized without disturbing the orientation.

The wavelength dispersion characteristics of the retardation film can be arbitrarily determined according to the content of the structural unit derived from the compound (1). When the content of the structural unit derived from compound (1) among the structural units in the retardation film is increased, a more flat wavelength dispersion characteristic, and furthermore, a reverse wavelength dispersion characteristic that satisfies the equations (α) and (β) is exhibited. .

The wavelength dispersion characteristics of the retardation film can be confirmed by appropriate preliminary experiments. Hereinafter, it shows about the preliminary experiment in the case of using the compound (1) which is a preferable polymerizable liquid crystal. The retardation value of the retardation film obtained by preparing 2 to 5 kinds of liquid crystal compositions having different contents of the structural unit derived from compound (1), and preparing a retardation film having the same thickness as described below for each liquid crystal composition. A compound required to obtain a correlation between the content of the structural unit derived from compound (1) and the retardation value of the retardation film from the result, and from the obtained correlation to give a desired retardation value to the retardation film in the film thickness What is necessary is just to determine the content of the structural unit derived from (1).

The film thickness of the retardation film may be set to function most appropriately as a λ/4 plate. The thickness of the retardation film is preferably 1.5 to 10 µm, more preferably 1.5 to 8 µm, and particularly preferably 1.5 to 5 µm.

(Method of manufacturing a retardation film functioning as a λ/4 plate)

The manufacturing method of a retardation film is demonstrated below. First, additives such as an organic solvent, another liquid crystal compound, a polymerization initiator, a polymerization inhibitor, a photosensitizer or a leveling agent are added to the compound (1) as necessary to prepare a liquid crystal composition. In particular, since film formation becomes easy, it is preferable that the liquid crystal composition is in a liquid state. Moreover, since this liquid crystal composition preferably contains an organic solvent and has a function of curing the obtained retardation film, the liquid crystal composition preferably contains a polymerization initiator.

The amount of the polymerization initiator used is, for example, 0.1 parts by weight to 30 parts by weight, preferably 0.5 parts by weight to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. Within the above range, a polymerizable liquid crystal can be polymerized without disturbing the orientation of the polymerizable liquid crystal.

〔Polymerization inhibiting agent〕

The liquid crystal composition may contain a polymerization inhibitor. Examples of the polymerization inhibitor include hydroquinones having a substituent such as hydroquinone or alkyl ether, catechols having a substituent such as alkyl ether such as butylcatechol, pyrogallols, 2,2,6,6-tetramethyl-1- Radical supplements such as piperidinyloxy radicals, thiophenols, β-naphthylamines, or β-naphthols.

By using a polymerization inhibitor, polymerization of a polymerizable liquid crystal can be controlled, and stability of the obtained retardation film can be improved. The amount of the polymerization inhibitor used is, for example, 0.1 parts by weight to 30 parts by weight, preferably 0.5 parts by weight to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. Within the above range, a polymerizable liquid crystal can be polymerized without disturbing the orientation of the liquid crystal compound. In addition, in the case of using other liquid crystal compounds in addition to compound (1) as the polymerizable liquid crystal, the standard for the preferred amount of the polymerization inhibitor to be used is as described above.

〔Photo-sensitizer〕

The liquid crystal composition may include a photosensitizer. Examples of the photosensitizer include xanthones such as xanthone or thioxanthone, anthracenes having a substituent such as anthracene or alkyl ether, phenothiazine, or rubrene.

By using a photosensitizer, the polymerization of the polymerizable liquid crystal can be highly sensitized. The used amount of the photosensitizer is, for example, 0.1 parts by weight to 30 parts by weight, and preferably 0.5 parts by weight to 10 parts by weight based on 100 parts by weight of the polymerizable liquid crystal. If it is within the said range, it can superpose|polymerize without disturbing the orientation of a polymeric liquid crystal. In addition, in the case of using other liquid crystal compounds in addition to compound (1) as the polymerizable liquid crystal, the standard of the preferred amount of the photosensitizer is as described above.

〔Leveling agent〕

The liquid crystal composition may include a leveling agent. As a leveling agent, for example, additives for radiation curing paints (Bikchemy Japan: BYK-352, BYK-353, BYK-361N), paint additives (Toray Dow Corning, Ltd.: SH28PA, DC11PA, ST80PA), paint additives (Shin-Etsu Chemical Co., Ltd.: KP321, KP323, X22-161A, KF6001) or a fluorine-based additive (Dinippon Ink Chemical Co., Ltd.: F-445, F-470, F-479), etc. Can be mentioned.

The phase difference film can be smoothed by using a leveling agent. In addition, in the manufacturing process of an optical film, the fluidity|liquidity of a liquid liquid crystal composition can be controlled, or the crosslinking density of the obtained retardation film can be adjusted. The leveling agent is used in an amount of 0.1 parts by weight to 30 parts by weight, and preferably 0.5 parts by weight to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. If it is in the said range, this polymeric liquid crystal can be polymerized without disturbing the orientation of a polymeric liquid crystal.

〔Organic solvent〕

It is preferable that the liquid crystal composition contains an organic solvent as described above. As the organic solvent used for preparing the liquid crystal composition, an organic solvent capable of dissolving a polymerizable liquid crystal is preferable. Further, any solvent that is inert to the polymerization reaction may be used, and specifically, alcohols such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve or butyl cellosolve; Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, gamma butyrolactone or propylene glycol methyl ether acetate; Ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, or methyl isobutyl ketone; Aliphatic hydrocarbon solvents such as pentane, hexane or heptane; Aromatic hydrocarbon solvents such as toluene, xylene or chlorobenzene, acetonitrile, propylene glycol monomethyl ether, tetrahydrofuran, dimethoxyethane, ethyl lactate, chloroform, phenol, and the like. These organic solvents may be used alone, or may be used in combination of a plurality of them. Particularly, the composition of the present embodiment has excellent compatibility and can be dissolved in alcohols, ester solvents, ketone solvents, non-chlorine aliphatic hydrocarbon solvents, and non-chlorine aromatic hydrocarbon solvents, so that halogenated hydrocarbons such as chloroform are not used. It can be melted and applied without needing to.

The viscosity of the liquid crystal composition is preferably adjusted to, for example, 10 Pa·s or less, preferably about 0.1 to 7 Pa·s so as to facilitate application.

The concentration of the solid content in the liquid crystal composition is, for example, 5 to 50% by weight. When the concentration of the solid content is 5% or more, the retardation film tends not to become too thin, so it is preferable. Further, if it is 50% or less, it is preferable because there is a tendency that unevenness does not occur in the film thickness of the retardation film.

Subsequently, the liquid crystal composition is applied to the supporting substrate, dried, and polymerized to obtain a target retardation film on the supporting substrate. The production of this retardation film will be described in detail below.

[Unpolymerized film preparation process]

When the liquid crystal composition is applied on the supporting substrate and dried, an unpolymerized film is obtained. When the unpolymerized film shows a liquid crystal phase such as a nematic phase, the obtained retardation film has birefringence due to monodomain orientation. Since the unpolymerized film is oriented at a low temperature of about 0 to 120°C, preferably 25 to 80°C, a supporting substrate that is not necessarily sufficient in terms of heat resistance as exemplified above can be used as the alignment film. In addition, it is easy to handle because there is no crystallization even after further cooling to about 30 to 10°C after orientation. Further, by appropriately adjusting the coating amount or concentration of the composition, the film thickness can be adjusted so as to impart a desired retardation.

Examples of the method of applying the liquid crystal composition to the supporting substrate include an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a CAP coating method, or a die coating method. Further, a method of applying using a coater such as a dip coater, a bar coater, or a spin coater may be mentioned.

Examples of the supporting substrate include glass, plastic sheet, plastic film, or translucent film. In addition, as the translucent film, for example, a polyolefin film such as polyethylene, polypropylene, norbornene polymer, a polyvinyl alcohol film, a polyethylene terephthalate film, a polymethacrylic acid ester film, a polyacrylic acid ester film, a cellulose ester film, polyethylene or A phthalate film, a polycarbonate film, a polysulfone film, a polyethersulfone film, a polyetherketone film, a polyphenylene sulfide film, or a polyphenylene oxide film.

For example, by using the supporting substrate in a process requiring the strength of the film, such as a bonding process of a retardation film, a conveying process, and a storage process, it can be easily handled without tearing or the like.

Further, it is preferable to form an alignment film on the supporting substrate and apply the liquid crystal composition on the alignment film. It is preferable that the alignment film has a solvent resistance that does not dissolve in the liquid crystal composition when the liquid crystal composition is applied, has heat resistance during removal of the solvent or heat treatment, and does not peel off due to friction or the like during rubbing. The alignment layer can be formed of a composition containing a suitable polymer (composition for forming an alignment layer).

Examples of the polymer include polyamides and gelatins having an amide bond in the molecule, polyimide having an imide bond in the molecule, and a hydrolyzate thereof such as polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxa And polymers such as sol, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid or polyacrylic acid esters. These polymers may be used alone, or two or more of them may be mixed or airborne. These polymers can be easily obtained by polycondensation by dehydration or deamination, chain polymerization such as radical polymerization, anionic polymerization, cationic polymerization, coordination polymerization, ring-opening polymerization, or the like.

It is preferable that these polymers can be applied by dissolving in a solvent. An appropriate solvent can be selected according to the solubility of the polymer to be used. Specific examples of the solvent include alcohols such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve or butyl cellosolve; Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, gamma butyrolactone or propylene glycol methyl ether acetate; Ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, or methyl isobutyl ketone; Aliphatic hydrocarbon solvents such as pentane, hexane or heptane; Aromatic hydrocarbon solvents such as toluene, xylene or chlorobenzene, acetonitrile, propylene glycol monomethyl ether, tetrahydrofuran, dimethoxyethane, ethyl lactate, chloroform, and the like. These solvents may be used alone, or may be used in combination of a plurality of them.

In order to form an alignment film, a commercially available alignment film material may be used as it is. As a commercially available alignment film material, San-Eva (registered trademark, manufactured by Nissan Chemical Co., Ltd.) or Optoma (registered trademark, manufactured by JSR Corporation), and the like may be mentioned.

When such an alignment film is used, since it is not necessary to perform refractive index control by stretching, the in-plane variation of birefringence becomes small. Therefore, the effect of being able to provide a phase difference film of a large area that can cope with a large image display device is exhibited.

As a method of forming an alignment layer on the supporting substrate, for example, applying a solution containing a commercially available alignment layer material or a polymer used as the material of the alignment layer is applied onto the supporting substrate, and then annealing to form an alignment layer on the supporting substrate. Can be formed.

The thickness of the alignment film thus obtained is, for example, 10 nm to 10000 nm, preferably 10 nm to 1000 nm. When it is within the above range, the polymerizable liquid crystal can be aligned at a desired angle on the alignment layer.

In addition, these alignment films can be subjected to a rubbing treatment as necessary. Accordingly, the polymerizable liquid crystal can be aligned in a desired direction.

As a method of rubbing the alignment film, for example, a method of bringing a rubbing roll wound around a rubbing cloth and rotating on a stage to be brought into contact with the alignment film being conveyed can be used.

As described above, in the unpolymerized film preparation step, an unpolymerized film (liquid crystal layer) is laminated on the alignment film laminated on the supporting substrate. Therefore, it is possible to produce a film as a roll film.

Although drying of the solvent may be performed with the progress of polymerization, drying most of the solvent before polymerization is preferable from the viewpoint of film-forming properties.

Examples of the drying method of the solvent include methods such as natural drying, air drying, and vacuum drying. As a specific heating temperature, it is preferable that it is 10-120 degreeC, and it is more preferable that it is 25-80 degreeC. In addition, the heating time is preferably from 10 seconds to 60 minutes, and more preferably from 30 seconds to 30 minutes. When the heating temperature and the heating time are within the above ranges, a supporting base material having insufficient heat resistance can be used as the supporting base material.

[Unpolymerized film polymerization process]

In the unpolymerized film polymerization step, the polymerizable liquid crystal contained in the unpolymerized film obtained in the unpolymerized film preparation step is polymerized and cured (hereinafter, the polymerization of the polymerizable liquid crystal contained in this unpolymerized film is referred to as “the unpolymerized film. It may be called "polymerization"). Thereby, a film in which the orientation of the polymerizable liquid crystal is fixed, that is, a polymer film is obtained. Accordingly, a polymer film having a small change in refractive index in the plane direction of the film and a large change in refractive index in the normal direction of the film can be prepared.

The method of polymerizing the unpolymerized film is determined according to the kind of polymerizable liquid crystal to be used. As described above, in the case of using a preferred compound (1) as the polymerizable liquid crystal, ^{photopolymerization if the polymerizable group of P 1} and/or P ² contained in the compound (1) is photopolymerizable, and heat polymerization if the polymerizable group is thermally polymerizable. By polymerization, the unpolymerized film can be polymerized. In the present invention, it is particularly preferable to polymerize the unpolymerized film by photopolymerization. According to photopolymerization, since the unpolymerized film can be polymerized at a low temperature, the choice of heat resistance of the supporting substrate is wide. In addition, it becomes easy to manufacture industrially. In addition, photopolymerization is also preferable from the viewpoint of film-forming properties. Photopolymerization is performed by irradiating the unpolymerized film with visible light or ultraviolet light. From the viewpoint of handling properties, ultraviolet light is particularly preferred. Light may be irradiated while heating to a temperature at which compound (1) takes a liquid crystal phase. At this time, the polymerization film may be patterned by masking or the like.

Since the retardation film obtained by such a manufacturing method has good adhesion to the alignment film, it is easy to manufacture a retardation film.

Moreover, the retardation film obtained by using a polymerizable liquid crystal has an advantage of being a thin film compared to a stretched film that imparts a retardation by stretching.

In the above manufacturing method, following the above step, a step of peeling the supporting substrate may be included. By setting it as such a structure, the film obtained becomes a laminated body containing a support base material, an alignment film, and a retardation film. Further, in addition to the step of peeling the supporting substrate, a step of peeling the alignment film from the laminate may be further included. By setting it as such a structure, a retardation film without an alignment film can be obtained.

The retardation film thus obtained is excellent in transparency and is used as a film for various image display devices. As described above, the thickness of the retardation film to be formed varies depending on the retardation value of the retardation film to be obtained.

In the circularly polarizing plate of the present invention, a retardation film containing a liquid crystal material, which functions as a λ/4 plate, contains a foreign material. The foreign material is a foreign material that may be inevitably incorporated in the manufacturing process, and is, for example, a foreign material produced by an alignment treatment of a liquid crystal compound, and more specifically, a foreign material (rubbing residue) produced by a rubbing treatment. In the case where the retardation film is composed of a stretched film, such a foreign material does not exist in the first place, and even when a foreign material is present, it is presumed that it does not lead to a display defect due to the thickness of the stretched film. As described above, one of the features of the present invention is to prevent adverse effects of foreign matters, which may become a problem (display defect) in a form in which the retardation film contains a very thin liquid crystal material. Specifically, the actual number of foreign substances in the retardation film containing a liquid crystal material is 100/m2 or more in one embodiment, and may be, for example, about 150/m2 to 300/m2. The average particle diameter of the foreign material is typically 1.3 µm or less, and preferably 0.1 µm to 1.0 µm. In order to achieve such a range of the average particle diameter, it is preferable to perform a treatment of removing most of the foreign matter having a particle diameter of 3 µm or more by blowing air onto the surface of the alignment film on which the rubbing treatment has been performed after the rubbing treatment. On the other hand, in the circularly polarizing plate according to the embodiment of the present invention, the number of display defects is preferably 10 pieces/m 2 or less, and more preferably 8 pieces/m 2 or less. That is, according to the embodiment of the present invention, even if a large number of foreign matters exist in the retardation film, most of such foreign matters can be prevented from being recognized as display defects. In addition, the actual number of foreign bodies can be recognized and measured by observing the circularly polarizing plate with, for example, an optical microscope (eg, differential interference microscope). The number of display defects can be recognized and measured as a bright point in a pseudo-cross Nicol state obtained by disposing a circularly polarizing plate, for example, on an optical microscope, and disposing a circularly polarizing plate for inspection using a retardation film containing a stretched film.

The retardation film functioning as a λ/4 plate has a thickness of 1.5 µm or more, and its surface is substantially flat. The upper limit of the thickness of the retardation film is not particularly limited, but may be 5 µm. By setting it as such a thickness, even if a foreign material exists, the surface can be made substantially flat. In addition, in this specification, "substantially flat" means that there is no protrusion of 0.4 µm or more in height.

The ratio of the thickness of the retardation film to the average particle diameter of the foreign material is preferably 1.2 or more, and more preferably 1.5 to 4.0. If the ratio is within such a range, the generation of protrusions due to foreign matter can be reduced, and a substantially flat surface can be satisfactorily realized. As a result, display defects due to foreign substances can be prevented satisfactorily.

(2nd retardation film)

As the retardation film used in the present invention, one obtained by laminating and integrating a second retardation film on the retardation film described above may be used. In the case of using a laminate in which a plurality of types of retardation films, such as a second retardation film, are laminated as described above, at least one of the plurality of retardation films constituting the laminated body contains a liquid crystal material, and the formula ( It satisfies α) and equation (β), and has a film thickness of 1.5 µm or more. As the second retardation film, it is preferable to use one produced without performing a treatment such as rubbing treatment or photo-alignment treatment. Such a retardation film can suppress the occurrence of orientation defects and the like, and there are almost no bright spot defects, so that the display quality is not impaired. For example, as the second retardation film, those having a refractive index characteristic of nz>nx≥ny are preferably used. By having a second retardation film having such a refractive index characteristic, for example, when used as an antireflection polarizing plate, the angle dependence of the effect of absorbing reflected light is reduced, and the emission of reflected light reflected at various angles can be prevented. desirable.

In one embodiment, the second phase difference film exhibits a relationship in which the refractive index is nx=ny. Here, "nx=ny" includes not only the case where nx and ny are strictly the same, but also the case where nx and ny are substantially the same. Specifically, it means that Re(550) is less than 10 nm.

Rth (550) of the second retardation film is preferably -260 nm to -10 nm, more preferably -230 nm to -15 nm, and still more preferably -215 nm to -20 nm. Since the above effect becomes remarkable by being in such a range, it is preferable.

The second retardation film may be formed of any suitable material, and is not particularly limited, but is preferably a liquid crystal layer fixed in homeotropic alignment. The liquid crystal material (liquid crystal compound) capable of homeotropic alignment may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the liquid crystal layer include, for example, the liquid crystal compounds and forming methods described in Japanese Unexamined Patent Application Publication No. 2002-333642 [0020] to [0042]. In this case, the thickness is preferably 0.1 µm to 5 µm, more preferably 0.2 µm to 3 µm.

Re(550) at a wavelength of 550 nm of the retardation film on which the second retardation film is laminated is also 90 to 190 nm, preferably 110 to 170 nm, more preferably 120 to 160 nm. If Re (550) of the second retardation film is within this range, even if it is laminated with the first retardation film that functions as a lambda /4 plate, the retardation film of the laminate also functions as a lambda /4 plate.

In order to laminate and integrate the second retardation film, any adhesive layer or pressure-sensitive adhesive layer may be used. The adhesive layer or the pressure-sensitive adhesive layer is, for example, an acrylic pressure-sensitive adhesive made of a (meth)acrylic polymer as a base polymer, or a rubber-based pressure-sensitive adhesive formed of a rubber-based resin, has excellent optical transparency, adequate wettability, cohesiveness and adhesive properties, and weather resistance or It is preferable because it is excellent in heat resistance and the like. As the adhesive, various types such as water-based, solvent-based, hot-melt-based, active energy ray-curable type are used, but water-based adhesives or active energy ray-curable adhesives are suitable. In addition, any known adhesive layer or pressure-sensitive adhesive layer may be used.

(Circular polarizing plate)

Any suitable adhesive (adhesive layer) or pressure-sensitive adhesive is used for lamination of each layer constituting the circularly polarizing plate of the present invention. In the lamination of the polarizing film and the retardation film, typically, an active energy ray (for example, ultraviolet) curable adhesive or a pressure-sensitive adhesive layer is used. The thickness of the adhesive layer is preferably 0.01 µm to 7 µm, more preferably 0.01 µm to 5 µm, and still more preferably 0.01 µm to 2 µm. Further, the thickness of the pressure-sensitive adhesive layer is 1 to 30 µm, more preferably 3 to 20 µm, and still more preferably 3 to 15 µm.

The polarizing plate having the polarizing film or the protective film, and the retardation film may be subjected to a surface modification treatment such as a corona treatment or a plasma treatment, or a treatment such as forming an easily adhesive layer before lamination.

(Configuration of circular polarizing plate)

The configuration of the circularly polarizing plate of the present invention will be described in more detail.

For example, when using a single-sided protective polarizing plate having a protective film on only one side of the polarizing film, it can be set as a circularly polarizing plate composed of a protective film/polarizing film/adhesive layer/phase difference film. In addition, when using a double-sided protective polarizing plate having a protective film on both sides of a polarizing film, it can be set as a circularly polarizing plate composed of a protective film/polarizing film/protective film/adhesive adhesive layer/phase difference film.

In the above configuration, the angle formed by the absorption axis of the polarizing film and the slow axis of the retardation film is 35° to 55°, more preferably 38° to 52°, even more preferably 40° to 50°, and 42° to 48° is more preferable, and 44° to 46° is particularly preferable.

If the angle is within such a range, it is preferable because a desired circularly polarizing function can be realized. In addition, when referring to an angle in the specification, the angle includes an angle in both a clockwise direction and a counterclockwise direction unless otherwise specified.

The circularly polarizing plate of the present invention may contain an intervening layer such as an adhesive layer, an adhesive layer, or an undercoat layer (primer layer), or an easily adhesive layer other than those described above.

In addition, a functional layer may be provided on the circularly polarizing plate of the present invention. By providing a functional layer, it is preferable because it can suppress generation|occurrence|production of defects, such as a penetration crack and nano slits, which occur in a polarizing film. The functional layer can be formed of various forming materials. The functional layer can be formed, for example, by applying a resin material to a polarizing film.

Examples of the resin material forming the functional layer include polyester resins, polyether resins, polycarbonate resins, polyurethane resins, silicone resins, polyamide resins, polyimide resins, PVA resins, acrylic resins, etc. Can be mentioned. These resin materials may be used alone or in combination of two or more, but among them, at least one selected from the group consisting of polyurethane-based resins and polyvinyl alcohol (PVA)-based resins is preferred, and PVA-based resins Is more preferable. In addition, the form of the resin may be either water-based or solvent-based. The form of the resin is preferably a water-based resin, and a PVA-based resin. In addition, an aqueous acrylic resin solution or an aqueous urethane resin solution can be used as the aqueous resin.

If the functional layer is too thick, optical reliability and water resistance are deteriorated, so the thickness of the functional layer is preferably 15 µm or less, more preferably 10 µm or less, even more preferably 8 µm or less, and even more preferably 6 µm or less. And 5 µm or less is more preferable, and 3 µm or less is particularly preferable. On the other hand, the thickness of the functional layer is preferably 0.2 µm or more, more preferably 0.5 µm or more, and even more preferably 0.7 µm or more. It is preferable because the occurrence of cracks can be suppressed by the functional layer having the above thickness.

(Circular polarizing plate with adhesive)

The circularly polarizing plate of the present invention can be made into a circularly polarizing plate with an adhesive by forming an adhesive layer on at least one of the surfaces. The pressure-sensitive adhesive layer can be formed on the opposite side from the polarizing film side based on the retardation film. The pressure-sensitive adhesive to be used is not particularly limited, and a known adhesive can be used.

As this pressure-sensitive adhesive layer, any one having excellent optical transparency and exhibiting appropriate adhesive properties such as wettability, cohesiveness, and adhesiveness may be used, but those having excellent durability and the like are preferably used. Specifically, as the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer, for example, a pressure-sensitive adhesive (also referred to as an acrylic pressure-sensitive adhesive or rubber-based pressure-sensitive adhesive) containing an acrylic resin or a rubber-based resin may be mentioned.

The pressure-sensitive adhesive layer formed of the acrylic pressure-sensitive adhesive is not particularly limited, but (meth)acrylic acid esters such as butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. A type resin or a copolymer resin using two or more types of these (meth)acrylic acid esters is preferably used. In addition, a polar monomer is copolymerized with these resins. As a polar monomer, for example, (meth)acrylic acid, (meth)acrylate 2-hydroxypropyl, (meth)acrylate 2-hydroxyethyl, (meth)acrylamide, 2-N,N-dimethylaminoethyl (meth)acrylate And monomers having polar functional groups such as a carboxyl group such as glycidyl (meth)acrylate, a hydroxyl group, an amide group, an amino group and an epoxy group. In addition, the pressure-sensitive adhesive is usually blended with an acrylic resin and a crosslinking agent.

In addition, various additives may be blended in the pressure-sensitive adhesive. Suitable additives include silane coupling agents and antistatic agents. The silane coupling agent is effective in enhancing the adhesion to glass. Antistatic agents are effective in reducing or preventing the generation of static electricity.

It is preferable that the thickness of at least one of the pressure-sensitive adhesives is 3 to 50 µm. More preferably, it is 3-30 micrometers.

In the case where the pressure-sensitive adhesive layer has conductivity, the resistance value may be appropriately selected. For example, it is preferably in the range of ^{1×10 9 to} 1×10 ^{11 Ω/□.}

The method of forming the pressure-sensitive adhesive layer formed on the circularly polarizing plate can be formed by a known method.

(Laminate)

A laminate can be obtained by laminating a window to be described later or a touch sensor to be described later on the circularly polarizing plate of the present invention. In addition to the windows described later, glass may be used. Examples of the laminate include a laminate comprising a circularly polarizing plate and a touch sensor, a laminate comprising a circularly polarizing plate and a window, or a laminate comprising a circularly polarizing plate, a touch sensor, and a window. In a laminate comprising a circularly polarizing plate, a touch sensor, and a window, a window, a touch sensor, and a circularly polarizing plate may be stacked in this order, and a window, a circularly polarizing plate, and a touch sensor may be stacked in this order.

(Image display device)

The image display device of the present invention is characterized by having the circularly polarizing plate or laminate of the present invention. For example, the circularly polarizing plate may be laminated on the image display device through the pressure-sensitive adhesive layer.

Any known type of image display device can be used. For example, the circularly polarizing plate of the present invention can be suitably used for an organic EL display device. In particular, it can be suitably used as an antireflection polarizing plate for a flexible organic EL display device.

(Flexible image display device)

The flexible image display device includes a laminate for a flexible image display device and an organic EL display panel, and a laminate for a flexible image display device is disposed on the viewer side with respect to the organic EL display panel so that it can be folded and bent. The laminated body for a flexible image display device may include a window, a circularly polarizing plate, and a touch sensor, and the order of stacking them is arbitrary, but the order of the window, circularly polarizing plate, touch sensor or window, touch sensor, and circularly polarizing plate from the viewer side. It is preferable that they are laminated. If the circularly polarizing plate is present on the visual recognition side of the touch sensor, the pattern of the touch sensor becomes difficult to be visually recognized, and the visibility of the displayed image is improved, which is preferable. Each member may be laminated using an adhesive or an adhesive.

In addition, a light blocking pattern may be provided on any one layer of the window, the circular polarizing plate, and the touch sensor.

(window)

The window is disposed on the visible side of the flexible image display device, and serves to protect other components from external impacts or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer, but a window in a flexible image display device is not rigid and rigid like glass, but has a flexible characteristic. The window includes a flexible transparent substrate, and may include a hard coat layer on at least one surface.

The transparent substrate used for the window has a visible light transmittance of 70% or more, preferably 80% or more. As the transparent substrate, any transparent polymer film may be used. Specifically, (modified) polyolefins such as polyethylene, polypropylene, polymethylpentene, norbornene or cycloolefin derivatives having a monomer unit containing a cycloolefin, diacetyl cellulose, triacetyl cellulose, propionyl cellulose, etc. Cellulose, acrylics such as methyl methacrylate (co)polymers, polystyrenes such as styrene (co)polymers, acrylonitrile/butadiene/styrene copolymers, acrylonitrile/styrene copolymers, ethylene-vinyl acetate copolymers , Polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyesters such as polyarylate, polyamides such as nylon, polyimides, polyamides Films formed of polymers such as imides, polyetherimides, polyethersulfones, polysulfones, polyvinyl alcohol, polyvinyl acetals, polyurethanes, and epoxy resins may be used. These polymers may be used alone or in combination of two or more. This polymer film may be any of an unstretched, uniaxial or biaxially stretched film. Preferably, among the transparent substrates described above, a polyamide film, polyamide-imide film or polyimide film, polyester film, olefin film, acrylic film, and cellulose film are preferred among the transparent substrates described above. In the polymer film, it is also preferable to disperse inorganic particles such as silica, organic fine particles, rubber particles, and the like. Further, a coloring agent such as a pigment or dye, an optical brightener, a dispersant, a plasticizer, a heat stabilizer, a light stabilizer, an infrared absorber, an ultraviolet absorber, an antistatic agent, an antioxidant, a lubricant, a solvent, and the like may be contained. The thickness of the transparent substrate is 5 to 200 µm, preferably 20 to 100 µm.

The window may have a hard coat layer formed on at least one surface of the transparent substrate. The thickness of the hard coat layer is not particularly limited, and may be, for example, 2 to 100 µm. If the thickness of the hard coat layer is within such a range, there is an effect of ensuring sufficient scratch resistance and excellent bending resistance. In addition, it is also possible to reduce the occurrence of curls due to cure shrinkage.

The hard coat layer may be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure by irradiation with active energy rays or thermal energy. Among them, the ones obtained by curing with active energy rays are preferable. An active energy ray is defined as an energy ray capable of generating an active species by decomposing a compound that generates an 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. Ultraviolet rays are particularly preferred. The hard coat composition contains at least one polymer of a radical polymerizable compound and a cationic polymerizable compound.

The radical polymerizable compound is a compound having a radical polymerizable group. The radical polymerizable group of the radical polymerizable compound may be a functional group capable of causing a radical polymerization reaction, and examples thereof include a group containing a carbon-carbon unsaturated double bond. Specifically, a vinyl group, a (meth)acryloyl group, etc. are mentioned. Further, when the radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be the same or different. The number of radically polymerizable groups in one molecule of the radical polymerizable compound is preferably two or more from the viewpoint of improving the hardness of the hard coat layer. As the radical polymerizable compound, a compound having a (meth)acryloyl group is particularly preferable from the viewpoint of high reactivity, and is a polyfunctional acrylate monomer having 2 to 6 (meth)acryloyl groups per molecule. Compounds called epoxy (meth) acrylate, urethane (meth) acrylate, and polyester (meth) acrylate oligomers having several (meth) acryloyl groups in a molecule having a molecular weight of hundreds to thousands can be preferably used. have. It is preferable to include at least one selected from epoxy (meth) acrylate, urethane (meth) acrylate and polyester (meth) acrylate.

The cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, and a vinyl ether group. The number of cationic polymerizable groups in one molecule of the cationic polymerizable compound is preferably two or more, and more preferably three or more, from the viewpoint of improving the hardness of the hard coat layer. Further, as the cationic polymerizable compound, a compound having at least one of an epoxy group and an oxetanyl group as a cationic polymerizable group is particularly preferable. Cyclic ether groups, such as an epoxy group and an oxetanyl group, are preferable from the viewpoint that the shrinkage due to the polymerization reaction is small. In addition, the compound having an epoxy group among the cyclic ether groups has the advantage that it is easy to obtain compounds of various structures, does not adversely affect the durability of the obtained hard coat layer, and is easy to control compatibility with the radical polymerizable compound. In addition, the oxetanyl group among the cyclic ether groups tends to have a higher degree of polymerization compared to the epoxy group, has low toxicity, and accelerates the rate of network formation obtained from the cationic polymerizable compound of the obtained hard coat layer, even in a region where it is mixed with the radical polymerizable compound. There is an advantage of forming an independent network without leaving unreacted monomers in the film.

As a cationic polymerizable compound having an epoxy group, for example, an alicyclic epoxy obtained by epoxidating a polyglycidyl ether of a polyhydric alcohol having an alicyclic ring, a cyclohexene ring, or a cyclopentene ring-containing compound with a suitable oxidizing agent such as hydrogen peroxide or peracid. Suzy; Aliphatic epoxy resins such as polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, polyglycidyl esters of aliphatic long-chain polybasic acids, homopolymers of glycidyl (meth)acrylates, and copolymers; Bisphenols such as bisphenol A, bisphenol F or hydrogenated bisphenol A, or derivatives such as alkylene oxide adducts and caprolactone adducts thereof, and glycidyl ether prepared by reaction with epichlorohydrin, and furnace And a glycidyl ether type epoxy resin derived from bisphenols, such as a rock epoxy resin.

The hard coat composition may further include a polymerization initiator. Examples of the polymerization initiator include a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, and the like, and may be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations to advance radical polymerization and cationic polymerization.

The radical polymerization initiator only needs to be capable of releasing a substance for starting radical polymerization by at least one of irradiation with active energy rays and heating. Examples of the thermal radical polymerization initiator include organic peroxides such as hydrogen peroxide and hyperbenzoic acid, and azo compounds such as azobisbutyronitrile.

Active energy ray radical polymerization initiators include type 1 radical polymerization initiators that generate radicals by decomposition of molecules, and type 2 radical polymerization initiators that coexist with tertiary amines to generate radicals through hydrogen release reactions. It can also be used in combination or in combination.

The cationic polymerization initiator should be capable of releasing a substance for starting cationic polymerization by at least one of irradiation with active energy rays and heating. As a cationic polymerization initiator, an aromatic iodonium salt, an aromatic sulfonium salt, a cyclopentadienyl iron (II) complex, etc. can be used. These can initiate cationic polymerization by either or both of irradiation with active energy rays or heating, depending on the difference in structure. The polymerization initiator may contain 0.1 to 10% by weight based on 100% by weight of the total hard coat composition. When the content of the polymerization initiator is less than 0.1% by weight, curing cannot sufficiently proceed, and it is difficult to implement the mechanical properties or adhesion of the finally obtained coating film, and when it exceeds 10% by weight, poor adhesion or cracking due to cure shrinkage Development and curling may occur.

The hard coat composition may further include one or more selected from the group consisting of solvents and additives. The solvent is capable of dissolving or dispersing the polymerizable compound and the polymerization initiator, and can be used without limitation if known as a solvent for the hard coat composition in the art. The additive may further include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

(Touch sensor)

The touch sensor is used as an input means. As the touch sensor, 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, and any method may be used. Among them, the electrostatic capacity method is preferable. The capacitive touch sensor is divided into an active area and an inactive area located at an outer portion of the active area. The active area is an area corresponding to an area where a screen is displayed (display unit) on the display panel, an area in which a user's touch is sensed, and the inactive area is an area corresponding to an area where the screen is not displayed on the display device (non-display unit) . The touch sensor includes a substrate having a flexible characteristic; A sensing pattern formed in the active region of the substrate; It is formed in the non-active region of the substrate, and may include each sensing line for connecting to an external driving circuit through the sensing pattern and the pad portion. As the substrate having flexible properties, the same material as the transparent substrate for the window can be used. It is preferable that the substrate of the touch sensor has a toughness of 2,000 MPa% or more from the viewpoint of suppressing cracks of the touch sensor. More preferably, the toughness may be from 2,000 MPa% to 30,000 MPa%.

The sensing pattern may include a first pattern formed in a first direction and a second pattern formed in a second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed on the same layer, and each pattern must be electrically connected in order to sense a touched point. In the first pattern, each unit pattern is interconnected through a joint, but since the second pattern has a structure in which each unit pattern is separated from each other in the form of an island, a separate bridge electrode is used to electrically connect the second pattern. I need this. As the sensing pattern, a known transparent electrode material may be applied. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), PEDOT (poly(3,4-ethylenedioxythiophene)) , Carbon nanotubes (CNT), graphene, metal wires, and the like, and these may be used alone or in combination of two or more. Preferably, ITO can be used. The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, tellurium, and chromium. These may be used alone or in combination of two or more.

The bridge electrode may be formed on the insulating layer through the insulating layer on the sensing pattern, and the bridge electrode may be formed on the substrate, and the insulating layer and the sensing pattern may be formed thereon. The bridge electrode may be formed of the same material as the sensing pattern, or may be formed of a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of two or more of them. Since the first pattern and the second pattern must be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joint portion of the first pattern and the bridge electrode, or may be formed in the structure of a layer covering the sensing pattern. In the latter case, the bridge electrode may connect the second pattern through a contact hole formed in the insulating layer. The touch sensor is for appropriately compensating for a difference in transmittance between a patterned area in which a pattern is formed and a non-patterned area in which a pattern is not formed, specifically, a difference in light transmittance caused by a difference in refractive indices in these areas. As a means, an optical control layer may be further included between the substrate and the electrode, and the optical control layer may include an inorganic insulating material or an organic insulating material. The optical control layer may be formed by coating a photocurable composition including a photocurable organic binder and a solvent on a substrate. The photocurable composition may further include inorganic particles. The refractive index of the optical control layer may be increased by the inorganic particles.

The photocurable organic binder may include, for example, a copolymer of each monomer such as an acrylate-based monomer, a styrene-based monomer, and a carboxylic acid-based monomer. The photocurable organic binder may be, for example, a copolymer containing different repeating units such as an epoxy group-containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit. The inorganic particles may include, for example, zirconia particles, titania particles, alumina particles, and the like. The photocurable composition may further contain additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

Each layer (window, circularly polarizing plate, touch sensor) forming the laminate for a flexible image display device can be laminated with an adhesive. As adhesives, water-based adhesives, organic solvents, solvent-free adhesives, solid adhesives, solvent vaporizing adhesives, moisture curing adhesives, heat curing adhesives, anaerobic curing adhesives, active energy ray curing adhesives, curing agent mixture adhesives, heat melting adhesives, pressure sensitive adhesives What is generally used, such as an adhesive (adhesive) and a rewet adhesive, can be used. Among them, water-based adhesives, active energy ray-curable adhesives, and pressure-sensitive adhesives are often used. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive force, etc., and is 0.01 µm to 500 µm, preferably 0.1 µm to 300 µm, and there are a plurality of laminates for the flexible image display device, but each type of thickness May be the same or different.

(Shading pattern)

The light blocking pattern can be applied as at least a part of a bezel or a housing of a flexible image display device. The light-shielding pattern hides the wiring arranged at the edge of the flexible image display device and makes it difficult to recognize the image, thereby improving the visibility of the image. The shading pattern may be in the form of a single layer or a multilayer. The color of the shading pattern is not particularly limited, and has various colors such as black, white, and metallic colors. The shading pattern may be formed of a pigment for realizing color and a polymer such as acrylic resin, ester resin, epoxy resin, polyurethane, and silicone. These may be used alone or as a mixture of two or more. The shading pattern may be formed by various methods such as printing, lithography, and inkjet. The thickness of the shading pattern may be 1 µm to 100 µm, preferably 2 µm to 50 µm. In addition, it is also preferable to give a shape such as an inclination to the thickness direction of the light pattern.

Example

Hereinafter, the present invention will be described in more detail by showing examples, but the present invention is not limited by these examples. In the examples, the parts and% indicating the content to the amount used are based on weight unless otherwise specified. In addition, each physical property in the following examples was measured by the following method.

(1) Measurement of thickness:

It measured using a digital micrometer "MH-15M" manufactured by Shanikon Co., Ltd.

(2) Measurement of in-plane retardation and thickness direction retardation:

Using a phase difference meter “KOBRA (registered trademark)-WPR” based on the parallel Nicol rotation method manufactured by Oji-Isokugiki Co., Ltd., in-plane retardation and thickness direction at each wavelength at a temperature of 23°C. The retardation was measured.

(3) Actual number of foreign bodies

The circularly polarizing plates obtained in Examples and Comparative Examples were observed at 50 times magnification using a differential interference microscope (OLYMPUS LG-PS2), and the number of recognized foreign substances was measured.

(4) The number of indication defects

Using a digital optical microscope (digital microscope VHX-500, manufactured by G&C), the number of display defects was observed at a magnification of 100 times. Specifically, the circularly polarizing plate obtained in Examples and Comparative Examples was placed in a microscope, and the circularly polarizing plate produced in Production Example 5 described later was placed as a polarizing plate for inspection, and observation was performed in a pseudo-cross Nicol state. The number of observed bright spots was taken as the number of display defects.

[Production Example 1] Preparation of polarizing film

A polyvinyl alcohol film with a thickness of 30 μm (average polymerization degree of about 2400, saponification degree of 99.9 mol% or more) was uniaxially stretched by about four times by dry stretching, and immersed in pure water at 40° C. for 40 seconds while maintaining a tension state. Thereafter, dyeing treatment was performed by immersing in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.052/5.7/100 at 28°C for 30 seconds. Thereafter, it was immersed in an aqueous solution having a weight 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 maintaining the tension at 300 N, and the thickness 12 in which iodine is adsorbed and oriented to the polyvinyl alcohol film. A µm polarizing film was obtained.

[Production Example 2] Preparation of retardation film A

A 2% by mass aqueous solution of polyvinyl alcohol (polyvinyl alcohol 1000 complete saponification type, manufactured by Wako Pure Chemical Industries, Ltd.) was used as the composition for forming an alignment film.

To a mixture obtained by mixing the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B shown below in a mass ratio of 90:10, 1.0 part of a leveling agent (F-556; manufactured by DIC) and 2-dimethylamino- as a polymerization initiator 6 parts of 2-benzyl-1-(4-morpholinophenyl)butan-1-one ("Irgacure 369 (Irg369)", manufactured by BASF Japan Co., Ltd.) was added.

Further, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration was 13%, and the mixture was stirred at 80°C for 1 hour to obtain a liquid crystal composition.

The polymerizable liquid crystal compound A was produced by the method described in Japanese Unexamined Patent Application Publication No. 2010-31223. In addition, the polymerizable liquid crystal compound B was manufactured according to the method described in Japanese Patent Application Laid-Open No. 2009-173893. Each molecular structure is shown below.

[Polymerizable liquid crystal compound A]

[Polymerizable liquid crystal compound B]

[Production of a laminate comprising a supporting substrate, an alignment film, and an alignment liquid crystal cured film]

After corona treatment was performed on a 50 µm-thick cycloolefin film [product name "ZF-14-50" manufactured by Nippon Xeon Co., Ltd.] as a supporting substrate, the composition for forming an alignment film was applied with a bar coater, and at 60°C. It dried for 1 minute and further at 80 degreeC for 3 minutes, and formed the film of 89 nm thickness.

Next, rubbing treatment was performed on the surface of the obtained film to form an alignment film. The rubbing treatment was performed by using a semi-automatic rubbing device (brand name: LQ-008, manufactured by Joyogo Chemical Co., Ltd.) and fabric (trade name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.), The treatment was performed under the conditions of a press fit of 0.15 mm, a rotational speed of 500 rpm, and 16.7 mm/s. After that, compressed air was sprayed on the surface of the alignment film on which the rubbing treatment was performed. In addition, the rubbing treatment direction was made to be a 45° direction counterclockwise when viewed from the viewer side with respect to the absorption axis direction of the polarizing film when it adheres to the polarizing film.

Subsequently, the liquid crystal composition was applied to the alignment film using a bar coater, dried at 120° C. for 1 minute, and then ultraviolet rays were applied using a high-pressure mercury lamp (Ushio Denki's brand name: “Unicure VB-15201BY-A”). An alignment liquid crystal cured film was formed by irradiation (in a nitrogen atmosphere, accumulated light quantity at a wavelength of 365 nm: 500 mJ/cm 2 ), and a laminate comprising a substrate, an alignment film, and a retardation film was obtained.

Re(λ) of the retardation film produced by the above method was bonded to glass through an adhesive, and then the cycloolefin-based film as a supporting substrate was peeled off (the film obtained by peeling this cycloolefin-based film was referred to as “phase difference film A”. It was measured later. When the film thickness of the obtained retardation film A was measured with a laser microscope, the film thickness was 2.1 µm. The results of measuring the retardation value Re(λ) at each wavelength were Re(450)=121 nm, Re(550)=142 nm, and Re(650)=146 nm. Re(550) was in the range of 90 to 190 nm and functioned as a λ/4 plate. Re(450)/Re(550)=0.85, Re(650)/Re(550)=1.03, satisfying the relationship between the equations (α) and (β). In addition, since a protrusion of 0.4 µm or more in height was not recognized on the surface of the retardation film A, it was confirmed that it was substantially flat.

[Production Example 3] Preparation of retardation film B

A 2% by mass aqueous solution of polyvinyl alcohol (polyvinyl alcohol 1000 complete saponification type, manufactured by Wako Pure Chemical Industries, Ltd.) was used as the composition for forming an alignment film.

Next, 10 g of a polymerizable liquid crystal showing a nematic liquid crystal phase (manufactured by BASF, brand name Paliocolor LC242), and a photoinitiator for the polymerizable liquid crystal compound (manufactured by Chiba Specialty Chemicals, brand name Irgacure (registered trademark) 907) , 0.5 g of a benzotriazole-based ultraviolet absorber containing 1%) was dissolved in 40 g of toluene to prepare a liquid crystal composition.

After corona treatment was performed on a 50 µm-thick cycloolefin-based film [product name "ZF-14-50" manufactured by Nippon Xeon Co., Ltd.] as a supporting substrate, the composition for forming an alignment film was applied with a bar coater, and at 60°C. It dried for 1 minute and at 80 degreeC for 3 minutes, and formed the film of 95 nm thickness.

Next, rubbing treatment was performed on the surface of the obtained film to form an alignment film. The rubbing treatment uses a semi-automatic rubbing device (brand name: LQ-008, manufactured by Joyogo Chemical Co., Ltd.), and press-fitting with a cloth (brand name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.). The treatment was carried out under conditions of an amount of 0.15 mm, a rotational speed of 500 rpm, and 16.7 mm/s. In addition, the direction of the rubbing treatment was set to be a 45° direction counterclockwise when viewed from the viewer side with respect to the direction of the absorption axis of the polarizing film when it adhered to the polarizing film.

Next, the liquid crystal composition was applied onto this alignment film using a bar coater, and dried at 100°C for 1 minute. Thereafter, using a high-pressure mercury lamp, a phase difference film B was formed on this alignment film by irradiating ultraviolet rays (in a nitrogen atmosphere, the accumulated light amount at a wavelength of 365 nm: 1200 mJ/cm 2 ). When the film thickness of the obtained retardation film B was measured with a laser microscope, the film thickness was 973 nm. When the retardation value was measured, Re(550) = 135 nm, and the orientation angle was 75° with respect to the length direction of the TAC. Further, when the phase difference values of the wavelength 450 nm and the wavelength 650 nm were measured, Re(450)=145 nm and Re(650)=132 nm. Re(450)/Re(550)=1.07, Re(650)/Re(550)=0.98, which did not satisfy the relationship between equations (α) and (β). On the surface of the retardation film B, many protrusions having a height of 0.4 µm or more were observed, and were not substantially flat.

[Production Example 4] Preparation of the second retardation film C

After diluting a commercially available vertical alignment film (JALS-204R, manufactured by Nippon Kosei Rubber Co., Ltd.) on the surface of the base film (triacetyl cellulose film, thickness of 80 µm) 1:1 with methyl ethyl ketone, use a wire bar coater. It applied (application amount 2.4 ml/m 2 ). Immediately, it was dried for 120 seconds with a warm air of 120°C.

Next, 3.8 g of the following rod-shaped liquid crystal compound, 0.06 g of a photopolymerization initiator (Irgacure (registered trademark) 907), a sensitizer (Kayacure (registered trademark) DETX, manufactured by Nippon Kayaku Corporation) 0.02 g, the following A solution in which 0.002 g of the vertical alignment agent on the air interface side of was dissolved in 9.2 g of methyl ethyl ketone was prepared. On the side of the alignment layer of the film on which the alignment layer was formed, this solution was applied to a wire bar and heated at 100° C. for 2 minutes to align the rod-shaped liquid crystal compound. Subsequently, UV irradiation at 80°C with a 120 W/cm 2 high pressure mercury lamp for 20 seconds to crosslink the rod-shaped liquid crystal compound, and then allow to cool to room temperature to prepare a retardation layer having the characteristics of a positive C plate. The obtained retardation layer had a thickness of 0.5 µm and an Rth (550) of -70.3 nm.

Rod-shaped liquid crystal compound

Vertical orientation agent on the air interface side:

Exemplary compounds described in Japanese Patent Application No. 2003-119959 (II-4)

[Production Example 5] Preparation of circularly polarizing plate for inspection

On one side of the polarizing film obtained in Production Example 1, a polyvinyl alcohol-based adhesive was applied so that the thickness of the adhesive layer was 0.1 μm, and a protective film (triacetylcellulose (TAC) film (trade name: KC2UAW, thickness: 25 μm, After sticking (manufactured by Konica Minolta Co., Ltd.), drying was performed at 80°C for 2 minutes to prepare a polarizing plate with a single-sided protective film.

On the polarizing film side of the obtained single-sided protective film-equipped polarizing plate, through an acrylic adhesive (manufactured by Lintech, NCF #L2, thickness 5 µm), a retardation film (stretched film manufactured by Nippon Zeon Corporation; ZD12 series; Re) (550) = 141 nm). Here, it adhered so that the slow axis of the retardation film was 45° in the clockwise direction with respect to the absorption axis of the polarizing film.

[Example 1]

A protective film (triacetylcellulose (TAC) film (trade name: KC2UAW, thickness: 25 μm, Konica) while applying a polyvinyl alcohol-based adhesive so that the thickness of the adhesive layer becomes 0.1 μm on one side of the polarizing film obtained in Preparation Example 1 After attaching (manufactured by Minolta), drying was performed at 80° C. for 2 minutes to prepare a polarizing plate with a single-sided protective film On the polarizing film side of the obtained polarizing plate with a single-sided protective film, an acrylic adhesive (manufactured by Lintech, NCF#) L2, thickness 5 µm), the retardation film A obtained in Production Example 2 was pasted together so that the slow axis of the retardation film A is 45 degrees counterclockwise with respect to the absorption axis of the polarizing film. After peeling the base film of the retardation film A, an acrylic pressure-sensitive adhesive (manufactured by Lintech, P-3132, thickness 25 μm) was attached to obtain a circularly polarizing plate. It had a structure including an adhesive layer/phase difference film A/acrylic adhesive/separator.

The obtained circularly polarizing plate was cut into dimensions of 100 mm x 100 mm. The obtained circularly polarizing plate was used for the evaluation of the above (3) and (4). As a result of inspecting 100 sheets of the obtained circularly polarizing plate, the actual number of foreign matters of the retardation film A was about 200 pieces/m 2, and the number of display defects of the circularly polarizing plate was 7 pieces/m 2. The foreign material was polyvinyl alcohol and was a rubbing residue.

[Example 2]

A protective film (triacetylcellulose (TAC) film (trade name: KC2CT, thickness: 20 μm, Konica Minolta) while applying a polyvinyl alcohol-based adhesive so that the thickness of the adhesive layer becomes 0.1 μm on both sides of the polarizing film obtained in Preparation Example 1 Co., Ltd.) was attached, followed by drying at 80°C for 2 minutes to prepare a polarizing plate with a double-sided protective film.

An evaluation sample was produced in the same manner except that the polarizing plate with a single-sided protective film of Example 1 was changed to the above-described polarizing plate with a double-sided protective film. The obtained circularly polarizing plate had a structure including a TAC film/adhesive layer/polarizing film/adhesive layer/TAC film/acrylic pressure-sensitive adhesive layer/phase difference film A/acrylic pressure-sensitive adhesive/separator.

The obtained circularly polarizing plate was cut into dimensions of 100 mm x 100 mm. The obtained circularly polarizing plate was used for the evaluation of the above (3) and (4). As a result of examining 100 obtained circularly polarizing plates, the actual number of foreign matters of the retardation film was about 200 pieces/m 2, and the number of display defects of the circularly polarizing plate was 6 pieces/m 2. The foreign material was polyvinyl alcohol and was a rubbing residue.

[Example 3]

A protective film (triacetylcellulose (TAC) film (trade name: KC2UAW, thickness: 25 μm, Konica) while applying a polyvinyl alcohol-based adhesive so that the thickness of the adhesive layer becomes 0.1 μm on one side of the polarizing film obtained in Preparation Example 1 After attaching (manufactured by Minolta), drying was performed at 80° C. for 2 minutes to prepare a polarizing plate with a single-sided protective film On the polarizing film side of the obtained polarizing plate with a single-sided protective film, an acrylic adhesive (manufactured by Lintech, NCF#) L2, thickness 5 µm), the retardation film A obtained in Production Example 2 was pasted together so that the slow axis of the retardation film A is 45 degrees counterclockwise with respect to the absorption axis of the polarizing film. After the base film of the retardation film A was peeled off, the retardation film C obtained in Production Example 4 was pasted through an acrylic pressure sensitive adhesive (manufactured by Lintech, NCF #L2, thickness of 5 μm). After peeling the film, an acrylic pressure-sensitive adhesive (manufactured by Lintech, P-3132, thickness 25 μm) was attached to obtain a circularly polarizing plate The obtained circularly polarizing plate was a TAC film/adhesive layer/polarizing film/adhesive layer/phase difference film A It had a structure including /acrylic pressure-sensitive adhesive/phase difference film C/acrylic pressure-sensitive adhesive/separator.

The obtained circularly polarizing plate was cut into dimensions of 100 mm x 100 mm. The obtained circularly polarizing plate was used for the evaluation of the above (3) and (4). As a result of inspecting 100 sheets of the obtained circularly polarizing plate, the actual number of foreign matters of the retardation film A was about 200 pieces/m 2, and the number of display defects of the circularly polarizing plate was 7 pieces/m 2. The foreign material was polyvinyl alcohol and was a rubbing residue.

[Comparative Example 1]

A circularly polarizing plate was produced in the same manner except that the retardation film A of Example 1 was changed to the retardation film B obtained in Production Example 3.

The obtained circularly polarizing plate was cut into dimensions of 100 mm x 100 mm. The obtained circularly polarizing plate was used for the evaluation of the above (3) and (4). As a result of examining 100 sheets of the obtained circularly polarizing plate, the actual number of foreign matters of the retardation film was about 200 pieces/m 2, and the number of display defects of the circularly polarizing plate was 168 pieces/m 2. The foreign material was polyvinyl alcohol and was a rubbing residue.

Advantageous Effects of Invention According to the present invention, it is useful because it is possible to obtain a circularly polarizing plate that is very thin, has excellent antireflection properties, and has suppressed adverse effects on the display performance of an image display device caused by foreign substances.

Claims (6)

A polarizing film and a retardation film functioning as a λ/4 plate are provided in this order, and the angle formed by the absorption axis of the polarizing film and the slow axis of the retardation film is 35° to 55°,
The retardation film includes a liquid crystal material,
The retardation film satisfies the following formulas (α) and (β),
Re(450)/Re(550)≤1.00 (α)
1.00≤Re(650)/Re(550) (β)
The retardation film contains foreign substances,
The retardation film has a thickness of 1.5 μm or more,
A circularly polarizing plate having a substantially flat surface of the retardation film.
[In the formula, Re(450) represents an in-plane retardation value at a wavelength of 450 nm, Re(550) represents an in-plane retardation value at a wavelength of 550 nm, and Re(650) is an in-plane retardation value at a wavelength of 650 nm. Represents the phase difference value.] The circular polarizing plate according to claim 1, wherein the foreign material is a rubbing residue. A laminate comprising the circularly polarizing plate according to claim 1 or 2 and a touch sensor. An image display device comprising the circularly polarizing plate according to claim 1 or 2. An image display device having the laminate according to claim 3. The image display device according to claim 4 or 5, wherein the image display device is an organic electroluminescence display device.