JP2023011730A - Polarizing plate and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circularly polarizing plate having a retardation film, which shows a little change in reflection hues before and after the film is left in a high temperature environment.

SOLUTION: The circularly polarizing plate has a polarizing plate and a retardation film, in which the retardation film includes a retardation layer. The retardation film has a piercing elastic modulus of 15 gf/mm or more, where the piercing elastic modulus is an elastic modulus measured by a test using a needle having a tip with a diameter of 1 mmφ and 0.5R at a piercing speed of 0.33 cm/sec.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a polarizing plate and a display device.

2. Description of the Related Art In recent years, image display devices typified by organic electroluminescence (hereinafter also referred to as organic EL) display devices have rapidly spread. An organic EL display device is equipped with a circularly polarizing plate including a polarizer and a retardation film (λ/4 plate). By arranging the circularly polarizing plate, it is possible to prevent the reflection of external light and improve the visibility of the screen.

With the emergence of organic EL display devices, demand for thinner image display devices has increased, and thus thinner circular polarizers have also been demanded. A change from a conventional retardation film formed of a resin film to a retardation film formed using a liquid crystal compound that can be made thinner has been studied (see, for example, Patent Document 1). A retardation film using a polymerizable liquid crystal compound is produced by coating a polymerizable liquid crystal compound on a base material, aligning the compound, and fixing the alignment state by irradiating light as necessary. When a circularly polarizing plate having a retardation film formed from a polymerizable liquid crystal compound is placed in a high temperature environment, there is a problem that the hue of the circularly polarizing plate changes from the initial state to blue or red. Specifically, when the circularly polarizing plate is rectangular, the reflected hue near the four edges of the circularly polarizing plate sometimes changes to blue or red.

JP 2017-54093 A

An object of the present invention is to solve the above-mentioned problems, and to provide a circularly polarizing plate having a retardation film and having a small change in reflection hue before and after being placed in a high-temperature environment.

[1] A circularly polarizing plate having a polarizing plate and a retardation film,
The retardation film includes a retardation layer,
The retardation film has a puncture elastic modulus of 15 gf/mm or more,
The puncture elastic modulus is a circularly polarizing plate which is an elastic modulus measured by a test in which a needle with a tip diameter of 1 mmφ and 0.5R is used and the puncture speed is 0.33 cm/sec.
[2] The circularly polarizing plate has an adhesive layer on its surface,
The polarizing plate has a polarizer,
The retardation layer includes a layer in which a polymerizable liquid crystal compound is cured,
The circularly polarizing plate according to [1], wherein the retardation film is arranged between the polarizing plate and the pressure-sensitive adhesive layer.
[3] The circularly polarizing plate according to [2], wherein the polarizer is formed of a layer obtained by curing a liquid crystal compound.
[4] The shape of the circularly polarizing plate is substantially rectangular,
In the polarizing plate, a protective film is laminated on the surface of the polarizer opposite to the retardation film side,
The protective film is a stretched film,
The circularly polarizing plate according to [2] or [3], wherein the stretched direction of the protective film and the short side direction of the circularly polarizing plate are substantially parallel.
[5] The circularly polarizing plate according to any one of [1] to [4], wherein the retardation film includes two retardation layers.
[6] A circularly polarizing plate with a front plate, in which the circularly polarizing plate according to [1] to [5] and the front plate are laminated via an adhesive layer.
[7] A display device in which the circularly polarizing plate according to any one of [2] to [4] is laminated on a display element via the pressure-sensitive adhesive layer.

ADVANTAGE OF THE INVENTION According to this invention, it is a circularly-polarizing plate provided with a retardation film, Comprising: It can provide the circularly-polarizing plate with a small change of reflection hue before and behind putting in a high temperature environment.

It is an example of the schematic sectional drawing which shows the layer structure of a circularly-polarizing plate. 1 is an example of a schematic cross-sectional view showing a layer structure of an organic EL display device; FIG. It is a top view of a sample for evaluation.

<Circularly polarizing plate>
The circularly polarizing plate of the present invention comprises a polarizing plate and a retardation film. The polarizing plate and the retardation film can be laminated via an adhesive layer, for example. Examples of the adhesive layer include a pressure-sensitive adhesive layer and an adhesive layer, which will be described later. In the present invention, the polarizing plate refers to a laminate comprising a polarizer and a protective film laminated on one side or both sides of the polarizer.

An example of the layer structure of the circularly polarizing plate of the present invention will be described below with reference to FIG. Note that FIG. 1 does not show an adhesive layer for laminating the polarizer 10 and the protective films 11 and 12, respectively. The circularly polarizing plate 100 shown in FIG. 1(a) has a first protective film 11 laminated on one side of the polarizer 10 and a second protective film 12 laminated on the other side of the polarizer 10. It has a layer structure in which a polarizing plate 1 and a retardation film 2 including a layer 20 in which a polymerizable liquid crystal compound is cured are laminated via an adhesive layer 13 . Further, the circularly polarizing plate 100 has an adhesive layer 14 on the surface of the retardation film 2 opposite to the polarizing plate 1 . The adhesive layer 14 can be an adhesive layer for bonding to an organic EL display element or the like.

Circularly polarizing plate 101 shown in FIG. 1B has first protective film 11 laminated on one side of polarizer 10 and second protective film 12 laminated on the other side of polarizer 10. It has a layer structure in which a polarizing plate 1 and a retardation film 2 are laminated with an adhesive layer 13 interposed therebetween. In the circularly polarizing plate 101 , the retardation film 2 has a layer structure in which a layer 20 obtained by curing a polymerizable liquid crystal compound and a layer 21 obtained by curing a polymerizable liquid crystal compound are laminated via an adhesive layer 15 . Further, the circularly polarizing plate 101 has an adhesive layer 14 on the surface of the retardation film 2 opposite to the polarizing plate 1 . The adhesive layer 14 can be an adhesive layer for bonding to an organic EL display element or the like.

Circularly polarizing plate 103 shown in FIG. 1C is composed of polarizing plate 1 in which first protective film 11 is laminated on one surface of polarizer 10, and retardation film 2, with adhesive layer 13 interposed therebetween. It has a laminated layer structure. In circularly polarizing plate 103 , polarizing plate 1 is a polarizing plate having a protective film only on one side of polarizer 10 . In the circularly polarizing plate 103 , the retardation film 2 has a layer structure in which a layer 20 obtained by curing a polymerizable liquid crystal compound and a layer 21 obtained by curing a polymerizable liquid crystal compound are laminated via an adhesive layer 15 . Further, the circularly polarizing plate 103 has an adhesive layer 14 on the surface of the retardation film 2 opposite to the polarizing plate 1 . The adhesive layer 14 can be an adhesive layer for bonding to an organic EL display element or the like.

As shown in FIG. 1, the retardation film may have one or two retardation layers. Further, the retardation film may have an alignment film for orienting the polymerizable liquid crystal compound in the manufacturing stage. As shown in FIG. 1, the polarizing plate may have a protective film laminated only on one surface of the polarizer, or may be laminated on both surfaces.

The circular polarizer can have layers other than those shown in FIG. Layers that the circularly polarizing plate may further include include a front plate and a light shielding pattern. The front plate can be arranged on the opposite side of the polarizing plate to the side on which the retardation film is laminated.

The light shielding pattern can be formed on the polarizing plate side surface of the front plate. The light shielding pattern is formed in the frame (non-display area) of the image display device, and can prevent the wiring of the image display device from being visually recognized by the user.

The shape of the principal surface of the circular polarizer can be substantially rectangular. By major surface is meant the surface having the largest area corresponding to the display surface. The term "substantially rectangular" means that at least one of the four corners (corners) has an obtuse angle or a rounded shape, or has an end face perpendicular to the main surface. A part has a concave part (notch) that is depressed in the in-plane direction, and a part of the main surface has a perforated part that is hollowed out in a circular, oval, polygonal, or combination of these shapes. It means to have or to have.

The size of the circularly polarizing plate is not particularly limited. When the circularly polarizing plate is substantially rectangular, the length of the long side is preferably 6 cm or more and 35 cm or less, more preferably 10 cm or more and 30 cm or less, and the length of the short side is 5 cm or more and 30 cm or less. 6 cm or more and 25 cm or less is more preferable.

<Polarizing plate>
In the present invention, the polarizing plate refers to a laminate comprising a polarizer and a protective film laminated on one side or both sides of the polarizer. The protective film included in the polarizing plate may have a surface treatment layer such as a hard coat layer, an antireflection layer, an antistatic layer, and the like, which will be described later. A polarizer and a protective film can be laminated via an adhesive layer or a pressure-sensitive adhesive layer, for example. Members included in the polarizing plate will be described below.

(1) Polarizer A polarizer provided in a polarizing plate absorbs linearly polarized light having a vibration plane parallel to its absorption axis, and transmits linearly polarized light having a vibration plane orthogonal to the absorption axis (parallel to the transmission axis). It can be an absorptive polarizer having properties. As the polarizer included in the first layer, a polarizer in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol resin film can be suitably used. The polarizer is, for example, a process of uniaxially stretching a polyvinyl alcohol resin film; a process of dyeing a polyvinyl alcohol resin film with a dichroic dye to adsorb a dichroic dye; It can be produced by a method including a step of treating an alcohol-based resin film with a cross-linking liquid such as an aqueous boric acid solution; and a step of washing with water after the treatment with the cross-linking liquid.

As the polyvinyl alcohol-based resin, a saponified polyvinyl acetate-based resin can be used. Examples of polyvinyl acetate-based resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate with other monomers that can be copolymerized. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

As used herein, "(meth)acryl" means at least one selected from acryl and methacryl. The same applies to "(meth)acryloyl", "(meth)acrylate" and the like.

The saponification degree of the polyvinyl alcohol resin is usually 85 to 100 mol %, preferably 98 mol % or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the polyvinyl alcohol resin is usually 1,000 to 10,000, preferably 1,500 to 5,000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined according to JIS K6726.

A film obtained by forming such a polyvinyl alcohol-based resin is used as a raw film for a polarizer (polarizer). A method for forming a polyvinyl alcohol-based resin into a film is not particularly limited, and a known method is employed. Although the thickness of the polyvinyl alcohol base film is not particularly limited, it is preferable to use a film having a thickness of 5 to 35 μm in order to make the thickness of the polarizer 15 μm or less. More preferably, it is 20 μm or less.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing with the dichroic dye, simultaneously with dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before or during the cross-linking treatment. Moreover, you may uniaxially stretch in these several steps.

In the uniaxial stretching, the film may be uniaxially stretched between rolls having different circumferential speeds, or may be uniaxially stretched using hot rolls. The uniaxial stretching may be dry stretching in which the film is stretched in the atmosphere, or wet stretching in which the polyvinyl alcohol resin film is stretched in a swollen state using a solvent or water. The draw ratio is usually 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 the film in an aqueous solution containing a dichroic dye is employed. Iodine and dichroic organic dyes are used as dichroic dyes. The polyvinyl alcohol resin film is preferably immersed in water before being dyed.

As a cross-linking treatment after dyeing with a dichroic dye, a method of immersing a dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid is usually adopted. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide.

The thickness of the polarizer is usually 30 µm or less, preferably 15 µm or less, more preferably 13 µm or less, still more preferably 10 µm or less, and particularly preferably 8 µm or less. The thickness of the polarizer is usually 2 μm or more, preferably 3 μm or more. The present inventors' investigation revealed that the change in hue of the circularly polarizing plate is caused by the change in the retardation value of the retardation film. Furthermore, it was clarified that the change in the retardation value of the retardation film is caused by the stress caused by the dimensional shrinkage of the circularly polarizing plate placed in a high-temperature environment. Therefore, from the viewpoint of reducing the influence of contraction of the polarizer, setting the thickness of the polarizer to 15 μm or less is effective in preventing the change in hue.

As a polarizer, for example, as described in JP-A-2016-170368, it may be formed from a layer in which a liquid crystal compound is cured. Specifically, a cured film in which a liquid crystal compound is polymerized has dichroic properties. Oriented dyes may also be used. As the dichroic dye, those having absorption in the wavelength range of 380 to 800 nm can be used, and organic dyes are preferably used. Dichroic dyes include, for example, azo compounds. A liquid crystal compound is a liquid crystal compound that can be polymerized while being aligned, and can have a polymerizable group in its molecule. This type of polarizer is produced by applying a composition containing a liquid crystal compound and a dichroic dye onto an alignment film and, if necessary, irradiating with ultraviolet rays or heating the liquid crystal compound and the dichroic dye. is obtained by fixing Further, as described in WO2011/024891 and JP-A-2018-120229, a polarizer may be formed from a dichroic dye having liquid crystallinity. Forming the polarizer from a layer in which the liquid crystal compound is cured in this way can contribute to reducing the dimensional change of the polarizer in a high-temperature environment, and is effective in preventing the hue from changing.

When a polarizer including a layer in which a liquid crystal compound is cured is used as the polarizer, the thickness of the polarizer can be 500 nm or more and 3 μm or less.

(2) Protective film The circularly polarizing plate of the present invention preferably has a protective film on at least one surface of the polarizer, and preferably has a protective film on the surface of the polarizer opposite to the retardation film side. . When the circularly polarizing plate is substantially rectangular and the protective film is a stretched film, it is preferable that the stretching direction of the protective film and the short side direction of the circularly polarizing plate are substantially parallel. When the circularly polarizing plate is substantially rectangular and the protective film is an unstretched film, the direction in which the tensile elastic modulus is the largest in the plane of the protective film and the short side direction of the circularly polarizing plate are substantially parallel. is preferred. When the stretching direction (or the direction of the highest tensile modulus) and the short side direction have such a relationship, the hue change of the circularly polarizing plate tends to be small regardless of the direction of the slow axis of the retardation film. It is in. When the stretched direction of the protective film (or the direction with the highest tensile modulus) is parallel to the short side, the shrinkage force in the stretched direction of the protective film due to stretching relaxation of the polarizer and the protective film in a high temperature environment is the long side. is smaller than when parallel to . For the tensile modulus, a value at 80° C. is adopted and measured by, for example, Autograph (registered trademark) (manufactured by Shimadzu Corporation, model number: AG-IS).

The stretched direction of the protective film and the short side direction of the circularly polarizing plate are substantially parallel, not only when both are strictly parallel, but also when the angle formed by the two is 0 ± 10 °. include. The angle formed by the stretched direction of the protective film and the short side direction of the circularly polarizing plate is preferably 0±5°. The unstretched film includes, in addition to the unstretched film, a substantially unstretched film having a stretch ratio of 1.1 times or less.

The protective films laminated on both sides of the polarizer are made of translucent (preferably optically transparent) thermoplastic resins such as linear polyolefin resins (polypropylene resins, etc.), cyclic polyolefin resins (norbornene polyolefin resins such as polyolefin resins); cellulose resins such as triacetyl cellulose and diacetyl cellulose; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate resins; meth) acrylic resin; polystyrene resin; polyvinyl chloride resin; acrylonitrile-butadiene-styrene resin; acrylonitrile-styrene resin; polyvinyl acetate resin; It can be a film made of a modified polyphenylene ether-based resin; a polysulfone-based resin; a polyethersulfone-based resin; a polyarylate-based resin; a polyamideimide-based resin;

Examples of linear polyolefin resins include polyethylene resins (polyethylene resins that are homopolymers of ethylene and copolymers that are mainly composed of ethylene), polypropylene resins (polypropylene resins that are homopolymers of propylene, and propylene resins that are mainly composed of propylene). In addition to homopolymers of chain olefins such as copolymers that form a chain olefin, copolymers composed of two or more types of chain olefins can be mentioned.

Cyclic polyolefin-based resin is a general term for resins polymerized using cyclic olefins as polymerized units, and is described, for example, in JP-A-1-240517, JP-A-3-14882, and JP-A-3-122137. resins. Specific examples of cyclic polyolefin-based resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically are random copolymers), graft polymers modified with unsaturated carboxylic acids or derivatives thereof, and hydrides thereof. Among them, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers as cyclic olefins are preferably used.

Polyester-based resins are resins having an ester bond, except for the cellulose ester-based resins described below, and generally consist of polycondensates of polyhydric carboxylic acids or derivatives thereof and polyhydric alcohols. Divalent dicarboxylic acids or derivatives thereof can be used as polyvalent carboxylic acids or derivatives thereof, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. Dihydric diols can be used as polyhydric alcohols, such as ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. A representative example of the polyester resin is polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol.

A (meth)acrylic resin is a resin containing a compound having a (meth)acryloyl group as a main constituent monomer. Specific examples of (meth)acrylic resins include, for example, poly(meth)acrylic acid esters such as polymethyl methacrylate; methyl methacrylate-(meth)acrylic acid copolymer; methyl methacrylate-(meth)acrylic acid Ester copolymer; methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymer; methyl (meth)acrylate-styrene copolymer (MS resin, etc.); (eg, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth)acrylate copolymer, etc.). Preferably, a polymer containing poly (meth)acrylic acid C _1-6 alkyl ester as a main component such as polymethyl (meth)acrylate is used, and more preferably a polymer containing methyl methacrylate as a main component (50 to 100 % by weight, preferably 70 to 100% by weight) is used.

Cellulose ester resin is an ester of cellulose and fatty acid. Specific examples of cellulose ester resins include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Copolymers thereof and those in which a part of hydroxyl groups are modified with other substituents are also included. Among these, cellulose triacetate (triacetylcellulose) is particularly preferred.

Polycarbonate-based resins are engineering plastics composed of polymers in which monomer units are linked via carbonate groups.

It is also useful to control the retardation value of the protective film to a value suitable for an image display device such as a liquid crystal display device. For example, in an in-plane switching (IPS) mode liquid crystal display device, it is preferable to use a film having substantially zero retardation value as the protective film. A substantially zero retardation value means that the in-plane retardation value Re(550) at a wavelength of 550 nm is 10 nm or less, and the absolute value of the thickness direction retardation value Rth at a wavelength of 550 nm is 10 nm or less. The absolute value of the thickness direction retardation value Rth at a wavelength of 480 to 750 nm is preferably 15 nm or less. Further, in order to improve the visibility of the screen when the user wears polarized sunglasses or the like, the in-plane retardation value Re(550) at a wavelength of 550 nm may be 70 to 140 nm.

For example, depending on the mode of the liquid crystal display device, the protective film may be stretched and/or shrunk to impart a suitable retardation. For example, for the purpose of viewing angle compensation, a single-layer or multi-layer protective film can be used.

The thickness of the protective film is usually 1 to 100 μm, preferably 5 to 60 μm, more preferably 10 to 55 μm, even more preferably 15 to 40 μm, from the viewpoint of strength and handleability.

The protective film attached to one side or both sides of the polarizer may be composed of the same kind of thermoplastic resin, or may be composed of different kinds of thermoplastic resins. Moreover, the thickness may be the same or may be different. Furthermore, they may have the same phase difference characteristics or different phase difference characteristics.

As described above, at least one of the protective films has, on its outer surface (the surface opposite to the polarizer), a hard coat layer, an antiglare layer, a light diffusion layer, an antireflection layer, a low refractive index layer, a charging A surface treatment layer (coating layer) such as an antifouling layer and an antifouling layer may be provided. The thickness of the protective film includes the thickness of the surface treatment layer.

The protective film can be attached to the polarizer via an adhesive layer or a pressure-sensitive adhesive layer, for example. As the adhesive for forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive or a thermosetting adhesive can be used, preferably a water-based adhesive or an active energy ray-curable adhesive. As the adhesive layer, those described later can be used.

Examples of water-based adhesives include adhesives composed of a polyvinyl alcohol-based resin aqueous solution, water-based two-liquid type urethane-based emulsion adhesives, and the like. Among them, a water-based adhesive composed of an aqueous polyvinyl alcohol resin solution is preferably used. Polyvinyl alcohol-based resins include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate with other monomers copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by saponifying a polymer, or a modified polyvinyl alcohol-based polymer obtained by partially modifying the hydroxyl groups thereof can be used. The water-based adhesive can contain cross-linking agents such as aldehyde compounds (glyoxal, etc.), epoxy compounds, melamine compounds, methylol compounds, isocyanate compounds, amine compounds, polyvalent metal salts, and the like.

When using a water-based adhesive, it is preferable to carry out a drying process for removing water contained in the water-based adhesive after bonding the polarizer and the protective film. After the drying step, a curing step of curing at a temperature of, for example, 20 to 45°C may be provided.

The active energy ray-curable adhesive is an adhesive containing a curable compound that is cured by irradiation with an active energy ray such as ultraviolet rays, visible light, electron beams, and X-rays, and is preferably an ultraviolet curable adhesive. is.

The curable compound can be a cationically polymerizable curable compound or a radically polymerizable curable compound. Examples of cationic polymerizable curable compounds include epoxy compounds (compounds having one or more epoxy groups in the molecule) and oxetane compounds (one or two or more oxetane rings in the molecule). compound), or a combination thereof. Examples of radically polymerizable curable compounds include (meth)acrylic compounds (compounds having one or more (meth)acryloyloxy groups in the molecule) and radically polymerizable double bonds. Other vinyl-based compounds or combinations thereof can be included. A cationic polymerizable curable compound and a radically polymerizable curable compound may be used in combination. The active energy ray-curable adhesive usually further contains a cationic polymerization initiator and/or a radical polymerization initiator for initiating the curing reaction of the curable compound.

When bonding the polarizer and the protective film, surface activation treatment may be applied to the bonding surface of at least one of them in order to enhance the adhesiveness. Surface activation treatments include dry treatments such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionizing active ray treatment (ultraviolet treatment, electron beam treatment, etc.). ; ultrasonic treatment using a solvent such as water or acetone, saponification treatment, and wet treatment such as anchor coating treatment can be mentioned. These surface activation treatments may be performed singly or in combination of two or more.

When the protective films are laminated on both sides of the polarizer, the adhesive for laminating these protective films may be of the same type or different types.

A protective layer may be formed on at least one surface of the polarizer instead of the protective film. The protective layer can be formed on the polarizer without an adhesive layer or pressure-sensitive adhesive layer, that is, the protective layer can be formed in contact with the polarizer. The protective layer can be a layer containing a (meth)acrylic resin or a layer containing a water-based resin.

A layer containing a (meth)acrylic resin is formed by applying a composition containing a (meth)acrylic resin to a polarizer, heating or irradiating an active energy ray, or applying a (meth)acrylic resin on a base film. It can be formed by applying a composition containing and heating or irradiating an active energy ray. In the latter case, a polarizer may be formed on the layer containing the (meth)acrylic resin.

A (meth)acrylic resin means a polymer whose main component is a monomer having a (meth)acryloyl group among the monomers constituting the (meth)acrylic resin. Here, the main component means a monomer having the largest content (% by mass) among the monomer components constituting the (meth)acrylic resin. By using a (meth)acrylic resin as a material for forming the protective layer, it is possible to suppress deterioration of the optical properties of the circularly polarizing plate even in a moist and hot environment.

The (meth)acrylic resin is preferably obtained by polymerizing a photopolymerizable monomer. For example, a monofunctional monomer or a polyfunctional monomer having a (meth)acryloyl group is polymerized alone or in combination of two or more. can be The (meth)acrylic resin may be polymerized with a monomer other than a (meth)acryloyl group-containing monomer, for example, a vinyl group-containing monomer.

The monomer having a (meth)acryloyl group is not particularly limited, but may include compounds having one or two or more (meth)acryloyl groups in the molecule, which may be used alone or in combination of two or more. can be used as Specifically, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethylene oxide or propylene oxide of the above (meth)acrylates Additive compound; oligoester (meth)acrylate, oligoether (meth)acrylate, oligourethane (meth)acrylate, oligoepoxy (meth)acrylate, oligomelamine (meth) having 4 or more (meth)acryloyl groups in the molecule Examples include acrylates and polyfunctional acrylates having a dendrimer structure.

The thickness of the layer containing the (meth)acrylic resin is usually 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, and usually 20.0 μm or less. It is preferably 15 μm or less, more preferably 10 μm or less. When the thickness of the layer containing the (meth)acrylic resin is within the above range, it becomes easier to obtain a bendable circularly polarizing plate.

A layer containing a water-based resin is formed by applying a composition containing a water-based resin to a polarizer and then heating or irradiating it with an active energy ray, or applying a composition containing a (meth)acrylic resin on a base film. , heating or irradiation with active energy rays. In the latter case, a polarizer may be formed on the layer containing the aqueous resin.

Water-based resins include water-soluble polymers such as polyvinyl alcohol, ethylene-vinyl acetate copolymer, polyvinylpyrrolidone, starches, methylcellulose, carboxymethylcellulose, and sodium alginate, among which polyvinyl alcohol is preferred.

The thickness of the layer containing the aqueous resin is preferably 0.1 μm or more, more preferably 0.3 μm or more, and is preferably 3 μm or less, more preferably 1.5 μm or less. , 1 μm or less. When the thickness of the layer containing the water-based resin is within the above range, it becomes easier to obtain a bendable circularly polarizing plate.

The protective layer may be a single layer or may be formed from multiple layers. An embodiment in which the protective layer is formed from a plurality of layers includes an embodiment in which the protective layer is composed of a layer containing a (meth)acrylic resin and a layer containing a water-based resin.

<Retardation film>
The circularly polarizing plate of the present invention has a retardation film. The puncture elastic modulus of the retardation film is 15 gf/mm or more, preferably 20 gf/mm or more, more preferably 25 gf/mm or more, further preferably 30 gf/mm or more. The upper limit of the puncture elastic modulus of the retardation film is not particularly limited, and may be, for example, 200 gf/mm or less, and may be 50 gf/mm or less. A retardation film having a puncture elastic modulus in such a range tends to be difficult to change its retardation value in a high-temperature environment. The larger the puncture elastic modulus, the less likely the retardation value will change with respect to the stress caused by the dimensional shrinkage of the polarizing plate.

When the retardation film includes one retardation layer, the puncture elastic modulus of the retardation film is 15 gf/mm or more, preferably 20 gf/mm or more, and more preferably 25 gf/mm or more. It is preferably 30 gf/mm or more, and more preferably 30 gf/mm or more. The upper limit of the puncture elastic modulus of the retardation film is not particularly limited, and may be, for example, 200 gf/mm or less, 90 gf/mm or less, or 50 gf/mm or less.

When the retardation film includes two retardation layers, the puncture elastic modulus of the retardation film is preferably 30 gf/mm or more, more preferably 40 gf/mm or more, and 50 gf/mm or more. It is more preferably 70 gf/mm or more, particularly preferably 70 gf/mm or more. The upper limit of the puncture elastic modulus of the retardation film is not particularly limited, and may be, for example, 200 gf/mm or less, 150 gf/mm or less, or 100 gf/mm or less.

The piercing elastic modulus is the force (gf) immediately before the retardation film breaks (or tears) when a needle (piercing jig) is pierced perpendicularly to the main surface of the retardation film. It means the value divided by the strain (mm). A needle having a tip diameter of 1 mmφ and 0.5R can be used. The needle penetration speed can be 0.33 cm/sec. The puncture elastic modulus is measured by sandwiching the retardation film between two plates having a circular hole with a diameter of 15 mm or less through which a needle can pass. The puncture elastic modulus can be measured in an environment at a temperature of 23°C. For example, the puncture elastic modulus of five retardation films can be measured, and the average value can be used as the puncture elastic modulus of the retardation film. A commercially available device can be used to measure the puncture modulus. Examples of commercially available devices include a handy compression tester “KES-G5 needle penetration force measurement specification” manufactured by Kato Tech Co., Ltd., and a small desktop tester “EZ Test” manufactured by Shimadzu Corporation.

The puncture elastic modulus of the retardation film can be controlled by, for example, adjusting the type of the polymerizable liquid crystal compound and alignment film used, the degree of curing of the polymerizable liquid crystal compound, the thickness of the retardation film, and the like.

A retardation film has a retardation layer. The retardation layer preferably has a layer composed of a composition containing a polymerizable liquid crystal compound. A layer composed of a composition containing a polymerizable liquid crystal compound specifically means a layer in which the polymerizable liquid crystal compound is cured. In the present specification, a layer giving a retardation of λ/2, a layer giving a retardation of λ/4 (positive A layer), a positive C layer, etc. may be collectively referred to as a retardation layer. Furthermore, the retardation film may contain an alignment film, which will be described later.

The layer that provides a retardation of λ/2 preferably means a layer having an in-plane retardation value of 200 to 280 nm at a wavelength of 550 nm, more preferably a layer having an in-plane retardation value of 215 to 265 nm. means that The layer that provides a retardation of λ/4 preferably means a layer having an in-plane retardation value of 100 to 160 nm at a wavelength of 550 nm, more preferably a layer having an in-plane retardation value of 110 to 150 nm. means that The positive C layer may be a layer having a refractive index relationship of nx≈ny<nz. The through-thickness retardation value of the positive C layer can be −50 nm to −150 nm and −70 nm to −120 nm at a wavelength of 550 nm.

A layer in which a polymerizable liquid crystal compound is cured is formed, for example, on an alignment film provided on a substrate. The base material may be a base material having a function of supporting the alignment film and formed in an elongated shape. This substrate functions as a release support and can support a retardation layer for transfer. Furthermore, it is preferable that the surface has adhesive strength to the extent that it can be peeled off. Examples of the base material include the resin films exemplified as the material of the protective film.

The thickness of the substrate is not particularly limited, but is preferably in the range of, for example, 20 μm or more and 200 μm or less. Strength is imparted when the thickness of the substrate is 20 μm or more. On the other hand, if the thickness is 200 μm or less, it is possible to suppress an increase in processing waste and wear of the cutting blade when cutting the base material into a sheet base material.

The substrate may be subjected to various antiblocking treatments. Anti-blocking treatments include, for example, easy-adhesion treatments, kneading treatments with fillers and the like, embossing (knurling treatments), and the like. By applying such antiblocking treatment to the base material, it is possible to effectively prevent sticking between the base materials when winding the base material, that is, so-called blocking, and to produce an optical film with high productivity. becomes possible.

A layer in which the polymerizable liquid crystal compound is cured is formed on the substrate via the alignment film. That is, the substrate and the alignment film are laminated in this order, and the layer in which the polymerizable liquid crystal compound is cured is laminated on the alignment film.

The alignment film is not limited to a vertical alignment film, and may be an alignment film that horizontally aligns the molecular axis of the polymerizable liquid crystal compound, or an alignment film that tilts the molecular axis of the polymerizable liquid crystal compound. . The alignment film has a solvent resistance that does not dissolve when a composition containing a polymerizable liquid crystal compound described later is applied, etc., and also has heat resistance in heat treatment for solvent removal and alignment of the liquid crystal compound. preferable. Examples of the alignment film include an alignment film containing an alignment polymer, a photo-alignment film, and a groove alignment film in which an uneven pattern or a plurality of grooves are formed on the surface for alignment. The thickness of the alignment film is usually in the range of 10 nm to 10000 nm, preferably 10 nm to 1000 nm, more preferably 500 nm or less, and still more preferably 10 nm to 200 nm. When the retardation film has an alignment film, increasing the thickness of the alignment film tends to increase the puncture elastic modulus.

The resin used for the alignment film is not particularly limited as long as it is a resin used as a material for a known alignment film. A cured product or the like can be used. Specifically, (meth)acrylate monomers include, for example, 2-ethylhexyl acrylate, cyclohexyl acrylate, diethylene glycol mono-2-ethylhexyl ether acrylate, diethylene glycol monophenyl ether acrylate, tetraethylene glycol monophenyl ether acrylate, trimethylolpropane triacrylate. , lauryl acrylate, lauryl methacrylate, isobornyl acrylate, isobornyl methacrylate, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxypropyl acrylate, benzyl acrylate, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, benzyl methacrylate , cyclohexyl methacrylate, methacrylic acid, urethane acrylate, and the like. In addition, as resin, these 1 types may be sufficient, and the mixture of 2 or more types may be sufficient.

Although the type of the polymerizable liquid crystal compound used in the present embodiment is not particularly limited, it is classified into a rod-shaped type (rod-shaped liquid crystal compound) and a disk-shaped type (disk-shaped liquid crystal compound, discotic liquid crystal compound) according to its shape. can. Furthermore, there are low-molecular-weight types and high-molecular-weight types, respectively. Polymers generally refer to those having a degree of polymerization of 100 or more (polymer physics, phase transition dynamics, Masao Doi, p. 2, Iwanami Shoten, 1992).

Any polymerizable liquid crystal compound can be used in the present embodiment. Furthermore, two or more kinds of rod-like liquid crystal compounds, two or more kinds of discotic liquid crystal compounds, or mixtures of rod-like liquid crystal compounds and discotic liquid crystal compounds may be used.

As the rod-like liquid crystal compound, for example, claim 1 of JP-A-11-513019, or paragraphs [0026] to [0098] of JP-A-2005-289980 can be preferably used. can be done. As the discotic liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP-A-2007-108732, or paragraphs [0013] to [0108] of JP-A-2010-244038 are suitable. can be used for

Two or more types of polymerizable liquid crystal compounds may be used in combination. In that case, at least one type has two or more polymerizable groups in the molecule. That is, the layer in which the polymerizable liquid crystal compound is cured is preferably a layer formed by fixing a liquid crystal compound having a polymerizable group by polymerization. In this case, it is no longer necessary to exhibit liquid crystallinity after forming a layer.

A polymerizable liquid crystal compound has a polymerizable group capable of undergoing a polymerization reaction. As the polymerizable group, for example, a functional group capable of an addition polymerization reaction such as a polymerizable ethylenically unsaturated group or a ring-polymerizable group is preferable. More specifically, examples of polymerizable groups include (meth)acryloyl groups, vinyl groups, styryl groups, and allyl groups. Among them, a (meth)acryloyl group is preferred. In addition, a (meth)acryloyl group is a concept including both a methacryloyl group and an acryloyl group.

The layer in which the polymerizable liquid crystal compound is cured can be formed by, for example, applying a composition containing the polymerizable liquid crystal compound onto the alignment film and irradiating it with an active energy ray, as described later. The composition may contain components other than the polymerizable liquid crystal compound described above. For example, the composition preferably contains a polymerization initiator. As the polymerization initiator to be used, for example, a thermal polymerization initiator or a photopolymerization initiator is selected according to the type of polymerization reaction. Examples of photopolymerization initiators include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, combinations of triarylimidazole dimers and p-aminophenyl ketones, and the like. The amount of the polymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the total solid content in the coating liquid.

Moreover, the composition may contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film. Polymerizable monomers include radically polymerizable or cationically polymerizable compounds. Among these, polyfunctional radically polymerizable monomers are preferred.

As the polymerizable monomer, one that can be copolymerized with the polymerizable liquid crystal compound described above is preferable. The amount of the polymerizable monomer used is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, based on the total mass of the polymerizable liquid crystal compound.

Further, the composition may contain a surfactant from the viewpoint of the uniformity of the coating film and the strength of the film. Surfactants include conventionally known compounds. Among them, fluorine-based compounds are particularly preferable.

Moreover, the composition may contain a solvent, and an organic solvent is preferably used.
Examples of organic solvents include amides (eg, N,N-dimethylformamide), sulfoxides (eg, dimethylsulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , chloroform, dichloromethane), esters (eg, methyl acetate, ethyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Among them, alkyl halides and ketones are preferred. Moreover, you may use together 2 or more types of organic solvents.

Further, the composition contains a vertical alignment accelerator such as a polarizer interface side vertical alignment agent and an air interface side vertical alignment agent, and a horizontal alignment accelerator such as a polarizer interface side horizontal alignment agent and an air interface side horizontal alignment agent. Various alignment agents may also be included. Furthermore, the composition may contain an adhesion improver, a plasticizer, a polymer, etc., in addition to the above components.

The active energy ray includes ultraviolet rays, visible light, electron beams and X-rays, preferably ultraviolet rays. Examples of the light source of the active energy ray include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, and wavelength ranges. LED light sources, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, etc., which emit light in the range of 380 to 440 nm can be used.

The irradiation intensity of ultraviolet rays is usually 100 mW/cm ² to 3,000 mW/cm ² . The ultraviolet irradiation intensity is preferably in the wavelength region effective for activating the cationic polymerization initiator or the radical polymerization initiator. The irradiation time of ultraviolet rays is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, still more preferably 0.1 seconds. ~1 minute.

The ultraviolet rays can be applied once or in multiple times. The ultraviolet rays are preferably applied multiple times. When the polymerization rate of the liquid crystal compound increases, the puncture elastic modulus tends to increase within the range of the present invention. Depending on the polymerization initiator used, the integrated amount of light at a wavelength of 365 nm is preferably 700 mJ/cm ² or more, more preferably 1,100 mJ/cm ² or more, and 1,300 mJ/cm ² or more. more preferably. Setting the integrated light amount to the above is advantageous for increasing the polymerization rate of the polymerizable liquid crystal compound constituting the retardation film and increasing the puncture elastic modulus of the retardation film. The integrated amount of light at a wavelength of 365 nm is preferably 2,000 mJ/cm ² or less, more preferably 1,800 mJ/cm ² or less. Using the above-described integrated light quantity may cause coloring of the retardation film.

Moreover, in order to prevent the alignment of the liquid crystal compound from being disturbed by the heat immediately after the ultraviolet irradiation, it is preferable to provide a cooling step after the ultraviolet irradiation. By providing the cooling step after the ultraviolet irradiation, it is possible to suppress the disturbance of the alignment of the liquid crystal compound due to the heat generated immediately after the irradiation. As a result, the degree of orientation of the liquid crystal compound increases, and a film having higher rigidity can be obtained. The cooling temperature can be, for example, 20° C. or lower, and can be 10° C. or lower. The cooling time can be, for example, 10 seconds or longer, or 20 seconds or longer.

In this embodiment, the thickness of the retardation layer is preferably 0.5 μm or more. Moreover, the thickness of the retardation layer is preferably 10 μm or less, more preferably 5 μm or less. In addition, the upper limit value and the lower limit value mentioned above can be combined arbitrarily. Sufficient durability is acquired as the thickness of a retardation layer is more than the said lower limit. When the thickness of the retardation layer is equal to or less than the upper limit, it can contribute to making the circularly polarizing plate thinner. The thickness of the retardation layer is a layer that provides a retardation of λ/4, a layer that provides a retardation of λ/2, or a desired in-plane retardation value of the positive C layer and a retardation value in the thickness direction. can be adjusted accordingly.

The retardation film may include one layer in which the polymerizable liquid crystal compound is cured, or may include two or more layers in which the polymerizable liquid crystal compound is cured. When the retardation film includes two layers in which the polymerizable liquid crystal compound is cured, the two layers are a layer giving a retardation of λ / 4 and a positive C layer, or a layer giving a retardation of λ / 4 and λ / 2 is preferably a layer that provides a retardation of When the retardation film includes two layers in which the polymerizable liquid crystal compound is cured, each layer in which the polymerizable liquid crystal compound is cured is formed on the alignment film, and both are laminated via an adhesive layer or a pressure-sensitive adhesive layer. Thus, the retardation film may be produced, or a layer further cured of the polymerizable liquid crystal compound may be formed on the layer of the cured polymerizable liquid crystal compound. After laminating both, the substrate and the alignment film can be peeled off. The thickness of the retardation film is preferably 3 to 30 μm, more preferably 5 to 25 μm.

<Adhesive layer>
The pressure-sensitive adhesive layer can be composed of a pressure-sensitive adhesive composition whose main component is a (meth)acrylic, rubber, urethane, ester, silicone, or polyvinyl ether resin. Among them, a pressure-sensitive adhesive composition using a (meth)acrylic resin as a base polymer, which is excellent in transparency, weather resistance, heat resistance, etc., is preferable. The adhesive composition may be active energy ray-curable or heat-curable. The thickness of the adhesive layer is usually 3-30 μm, preferably 3-25 μm.

Examples of the (meth)acrylic resin (base polymer) used in the adhesive composition include butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-(meth)acrylate. Polymers or copolymers containing one or more of (meth)acrylic acid esters such as ethylhexyl as monomers are preferably used. Preferably, the base polymer is copolymerized with a polar monomer. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, glycidyl ( Monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as meth)acrylates, can be mentioned.

The pressure-sensitive adhesive composition may contain only the above base polymer, but usually further contains a cross-linking agent. The cross-linking agent is a metal ion having a valence of 2 or more, which forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound, which forms an amide bond with a carboxyl group; Examples include epoxy compounds and polyols that form ester bonds with carboxyl groups; and polyisocyanate compounds that form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferred.

<Front panel>
The present invention includes a circularly polarizing plate with a front plate in which a circularly polarizing plate and a front plate are laminated via an adhesive layer. The front plate is arranged on the viewing side of the polarizing plate. The front plate can be laminated on the polarizing plate via an adhesive layer. Examples of the adhesive layer include the adhesive layer and the adhesive layer described above. As shown in FIGS. 2(a), (b), and (c), the front plate 4 can be laminated on the protective film 11 of the polarizing plate 1 with an adhesive layer 16 interposed therebetween.

Examples of the front plate include glass and a resin film having a hard coat layer on at least one surface thereof. As the glass, for example, high transmission glass or tempered glass can be used. Especially when using a thin transparent surface material, chemically strengthened glass is preferable. The thickness of the glass can be, for example, 100 μm to 5 mm.

A front panel comprising a hard coat layer on at least one surface of a resin film can have flexible characteristics, unlike existing glass, which is not rigid. The thickness of the hard coat layer is not particularly limited, and may be, for example, 5 to 100 μm.

Examples of resin films include cycloolefin derivatives having units of monomers containing cycloolefins such as norbornene or polycyclic norbornene monomers, cellulose (diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose , propionyl cellulose, butyryl cellulose, acetylpropionyl cellulose) ethylene-vinyl acetate copolymer, polycycloolefin, polyester, polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyamideimide, polyethersulfone, polysulfone, polyethylene, Polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyetherketone, polyetheretherketone, polyethersulfone, polymethylmethacrylate, polyethyleneterephthalate, polybutyleneterephthalate, polyethylenenaphthalate, polycarbonate , polyurethane, and epoxy. Unstretched, uniaxially stretched or biaxially stretched film can be used as the resin film. These polymers can be used alone or in combination of two or more. Resin films include polyamide-imide films or polyimide films with excellent transparency and heat resistance, uniaxially or biaxially oriented polyester films, and cycloolefin derivative films with excellent transparency and heat resistance that can be used for larger films. , polymethyl methacrylate films and transparent and optically non-anisotropic triacetyl cellulose and isobutyl ester cellulose films are preferred. The thickness of the resin film may be 5-200 μm, preferably 20-100 μm.

The hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure upon exposure to light or heat energy. The hard coat layer can be formed by curing a hard coat composition containing a photocurable (meth)acrylate monomer or oligomer and a photocurable epoxy monomer or oligomer at the same time. The photocurable (meth)acrylate monomer may include one or more selected from the group consisting of epoxy (meth)acrylate, urethane (meth)acrylate and polyester (meth)acrylate. The epoxy (meth)acrylate can be obtained by reacting an epoxy compound with a (meth)acryloyl group-containing carboxylic acid.

The hardcoat composition may further include one or more selected from the group consisting of solvents, photoinitiators and additives. The additive can include one or more selected from the group consisting of inorganic nanoparticles, leveling agents and stabilizers, and other components commonly used in the art, such as Oxidizing agents, UV absorbers, surfactants, lubricants, antifouling agents and the like can be further included.

<Light shielding pattern>
The light shielding pattern can be provided as at least part of the front panel or the bezel or housing of the display device to which the front panel is applied. The light shielding pattern can be formed on the display element side of the front panel. The light shielding pattern can hide each wiring of the display device so that it cannot be visually recognized by the user. The color and/or material of the light-shielding pattern is not particularly limited, and may be formed of resin materials having various colors such as black, white, and gold.
In one embodiment, the thickness of the light shielding pattern may range from 2 μm to 50 μm, preferably from 4 μm to 30 μm, more preferably from 6 μm to 15 μm. Further, in order to suppress the inclusion of bubbles due to the difference in level between the light shielding pattern and the display portion and the visibility of the boundary portion, the light shielding pattern can be given a shape.

<Method for manufacturing circularly polarizing plate>
A method for manufacturing a circularly polarizing plate will be described using the circularly polarizing plate 100 shown in FIG. 1(a) as an example. The circularly polarizing plate 100 can be produced by laminating the polarizing plate 1 and the retardation film 2 with the adhesive layer 13 interposed therebetween.

The polarizing plate 1 can be manufactured by laminating a polarizer 10 and protective films 11 and 12 with adhesive layers interposed therebetween. The polarizing plate may be produced by preparing long members, bonding the respective members together by roll-to-roll, and then cutting them into a predetermined shape, or by cutting each member into a predetermined shape. Afterwards, they can be pasted together. After bonding the protective films 11 and 12 to the polarizer 10, a heating process and a humidity control process may be provided.

The retardation film 2 can be manufactured, for example, as follows. An alignment film is formed on a substrate, and a coating liquid containing a polymerizable liquid crystal compound is applied onto the alignment film. While the polymerizable liquid crystal compound is oriented, it is irradiated with an active energy ray to cure the polymerizable liquid crystal compound. The pressure-sensitive adhesive layer 14 formed on the release film is laminated on the layer in which the polymerizable liquid crystal compound is cured. Then, the substrate and/or the alignment film are peeled off. Next, the adhesive layer 13 formed on the release film is laminated on the protective film 12 . The retardation film 2 may be manufactured by preparing long members, bonding the respective members together by roll-to-roll, and then cutting them into a predetermined shape, or by cutting each member into a predetermined shape. After cutting, it may be pasted together.

Then, the release film laminated on the adhesive layer 13 is peeled off, and the retardation film 2 and the polarizing plate 1 are bonded via the adhesive layer 13, whereby the circularly polarizing plate 100 can be produced. .

The color difference visually recognized within the plane of the circularly polarizing plate on the reflector after the heat resistance test can be reduced by uniformizing the reflection hue within the plane of the circularly polarizing plate after the heat resistance test. In order to make the reflection color uniform within the plane of the circularly polarizing plate after the heat resistance test, it is necessary to ensure that the reflection color is uniform within the plane of the circular polarizing plate before the heat resistance test, and that the reflection color does not change before and after the heat resistance test. There are small things.

It is preferable that the reflected hue of the circularly polarizing plate before the heat resistance test is uniform in the plane in order to reduce the difference in the reflected hue within the plane of the circularly polarizing plate after the heat resistance test. Specifically, the reflection hue at the center of the main surface before the heat resistance test (may be the center of gravity or the center point 5 shown in FIG. 3), and the portion other than the center of the main surface ( For example, the magnitude of the difference between the reflected hue and the reflected hue at a point 5 other than the center shown in FIG. It is more preferably 0.6 or less. The reflected hue difference between the central portion and other portions can be calculated, for example, from the following equation.
Δa*b*=[(Δa*) ² +(Δb*) ² ] ^1/2
where Δa* is the difference between a* in the central portion and a* in the non-central portion, and Δb* is the corresponding difference in b*. When the uniformity of the reflected hue in the plane of the circularly polarizing plate before the heat resistance test is low, even if the reflected hue change is small before and after the heat resistance test, the visibility improvement effect may be small. The heat resistance test can be performed, for example, by storing the circularly polarizing plate in a dryer set at a temperature of 80° C. for 168 hours.

<Application>
Circularly polarizing plates can be used in various display devices. A display device is a device having a display element, and includes a light-emitting element or a light-emitting device as a light source. Examples of display devices include liquid crystal display devices, organic EL display devices, inorganic electroluminescence (hereinafter also referred to as inorganic EL) display devices, electron emission display devices (for example, field emission display devices (also referred to as FED), and surface field emission displays). device (also called SED)), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection display device (for example, grating light valve (GLV) display device, digital micromirror device (DMD and piezoelectric ceramic displays, etc. Liquid crystal display devices include both transmissive liquid crystal display devices, transflective liquid crystal display devices, etc. These display devices can display two-dimensional images. It may be a display device that displays or a stereoscopic display device that displays a three-dimensional image.The circularly polarizing plate can be particularly effectively used in an organic EL display device or an inorganic EL display device. .

In FIGS. 2A and 2B, the organic EL display devices 104 and 105 have a circularly polarizing plate laminated on the organic EL display element 3 via an adhesive layer 14 laminated on the retardation film 20. It has a layered structure.

(1) Method for measuring film thickness Measured using MH-15M, a digital micrometer manufactured by Nikon Corporation.

(2) Method for measuring phase difference value Measured using a phase difference measuring device KOBRA-WPR (manufactured by Oji Scientific Instruments Co., Ltd.).

[Preparation of Retardation Film 1]
5 parts of a photo-alignable material having the following structure (weight average molecular weight: 30,000) and 95 parts of cyclopentanone (solvent) are mixed, and the resulting mixture is stirred at 80° C. for 1 hour to form an alignment film. A composition for

A leveling agent (F-556; manufactured by DIC Corporation) is added to 100 parts of a mixture obtained by mixing the following polymerizable liquid crystal compound A and polymerizable liquid crystal compound B at a mass ratio of 90:10, and 6 parts of 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (“Irgacure 369 (Irg369)”, manufactured by BASF Japan Ltd.) as a polymerization initiator were added.

Furthermore, 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 composition for forming a cured liquid crystal film.

Polymerizable liquid crystal compound A was produced by the method described in JP-A-2010-31223. Polymerizable liquid crystal compound B was produced according to the method described in JP-A-2009-173893. Each molecular structure is shown below.

(Polymerizable liquid crystal compound A)

(Polymerizable liquid crystal compound B)

[Production of Laminate Consisting of Base Material, Alignment Film, and Layer in which Polymerizable Liquid Crystal Compound is Cured]
Corona treatment was performed on a 50 μm-thick cycloolefin resin film [trade name “ZF-14-50” manufactured by Nippon Zeon Co., Ltd.] as a substrate. A composition for forming an alignment film was applied to the corona-treated surface with a bar coater. The coating film was dried at 80° C. for 1 minute. The dried coating film was irradiated with polarized UV at an axial angle of 45° using a polarized UV irradiation device (trade name “SPOT CURE SP-9” manufactured by Ushio Inc.) to obtain an alignment film. Irradiation with polarized UV was performed so that the integrated amount of light at a wavelength of 313 nm was 100 mJ/cm ² .

Subsequently, the composition for forming a liquid crystal cured film was applied onto the alignment film using a bar coater. The coating film was dried at 120° C. for 1 minute. The dried coating film was irradiated with ultraviolet rays using a high-pressure mercury lamp (trade name of Ushio Inc.: "Unicure VB-15201BY-A"). The UV irradiation step was performed in a nitrogen atmosphere so that the integrated amount of light at a wavelength of 365 nm was 250 mJ/cm ² . As a cooling step immediately after the irradiation, the cured film was placed in an oven set at 5° C. for 20 seconds. Immediately after taking out from the oven, the ultraviolet irradiation step and the cooling step were performed again to obtain a laminate comprising a substrate, an alignment film, and a layer in which the polymerizable liquid crystal compound was cured.

(Measurement of phase difference value)
A pressure-sensitive adhesive layer was laminated on the layer of the laminate in which the polymerizable liquid crystal compound was cured. The laminate was attached to glass via the pressure-sensitive adhesive layer. After that, the substrate included in the laminate was peeled off to obtain a sample for evaluating the retardation value. As a result, the layer in which the polymerizable liquid crystal compound was cured had Re (450) = 121 nm, Re (550) = 142 nm, and Re (650) = 146 nm as the retardation value Re (λ) at each wavelength. . As a result, Re(450)/Re(550)=0.85 and Re(650)/Re(550)=1.03 were calculated. The layer in which the polymerizable liquid crystal compound was cured was a layer giving a retardation of λ/4.

(Measurement of puncture elastic modulus)
The puncture elastic modulus was measured as follows. A needle was attached to a handy compression tester "KES-G5 needle penetration force measurement specification" manufactured by Kato Tech Co., Ltd. A needle was vertically pierced into the main surface of the laminate from which the substrate was peeled, which was fixed between two plates having a circular hole with a diameter of 11 mm, and the force (gf) immediately before breaking was measured. A value divided by the strain (mm) was calculated. This operation was performed for each of the five retardation films (puncture test samples), and the average value was taken as the puncture elastic modulus of the retardation film. A needle with a tip diameter of 1 mmφ and 0.5R was used. The needle piercing speed was 0.33 cm/sec. Table 1 shows the puncture elastic modulus of Retardation Film 1.

[Preparation of Retardation Film 2]
When curing the coating film of the composition for forming a liquid crystal cured film, the integrated amount of ultraviolet light per irradiation is 400 mJ/cm ² at a wavelength of 365 nm (that is, the total integrated amount of ultraviolet light irradiated twice is 800 mJ/cm ^2. ) A laminate including the retardation film 2 was produced in the same manner as in [Preparation of the retardation film 1], except that it was made to be. The puncture elastic modulus of the retardation film 2 was measured in the same manner as described above. Table 1 shows the puncture elastic modulus of the retardation film 2.

[Preparation of Retardation Film 3]
When curing the coating film of the composition for forming a liquid crystal cured film, the integrated amount of ultraviolet light per irradiation is 600 mJ/cm ² at a wavelength of 365 nm (that is, the total integrated amount of ultraviolet light irradiated twice is 1200 mJ/cm ^2. ) A laminate including the retardation film 3 was produced in the same manner as in [Preparation of the retardation film 1] except that the thickness was set as follows. The puncture elastic modulus of the retardation film 3 was measured in the same manner as described above. Table 1 shows the puncture elastic modulus of the retardation film 3.

[Preparation of Retardation Film 4]
When curing the coating film of the composition for forming a liquid crystal cured film, the integrated amount of ultraviolet light per irradiation is 800 mJ/cm ² at a wavelength of 365 nm (that is, the total integrated amount of ultraviolet light irradiated twice is 1600 mJ/cm ^2. ) A laminate including the retardation film 4 was produced in the same manner as in [Preparation of the retardation film 1], except that the thickness was set as follows. The puncture elastic modulus of the retardation film 4 was measured in the same manner as described above. Table 1 shows the puncture elastic modulus of the retardation film 4.

[Preparation of Retardation Film 5]
As a composition for forming a vertical alignment film, 5 parts by weight of Sanever SE-610 (manufactured by Nissan Chemical Industries, Ltd.), which is a commercially available alignment polymer, and 95 parts by weight of methyl ethyl ketone (solvent) were mixed to obtain a composition for forming a vertical alignment film. A composition was obtained.

As a composition for forming a vertical alignment retardation layer, 20 parts by weight of a photopolymerizable nematic liquid crystal compound (RMM28B manufactured by Merck) and 1 part by weight of Irgacure 907 (Irg-907 manufactured by BASF) as a photopolymerization initiator, It was dissolved in 80 parts by weight of propylene glycol monomethyl ether acetate to prepare a coating liquid for forming a vertical alignment retardation layer.

Corona treatment was performed on a 50 μm-thick cycloolefin resin film [trade name “ZF-14-50” manufactured by Nippon Zeon Co., Ltd.] as a substrate. A composition for forming a vertical alignment film was applied to the corona-treated surface using a bar coater. The coating film was cured by heating at 100° C. for 120 seconds to form a vertical alignment film.

A coating liquid for forming a vertical alignment retardation layer was applied onto the previously obtained vertical alignment film, and the coating film was heated at a temperature of 80° C. for 60 seconds. After that, ultraviolet rays (UVB) are irradiated so that the integrated amount of light becomes 220 mJ/cm ² to polymerize and cure the composition for forming a vertical alignment retardation layer to form a vertical film having a thickness of 0.7 μm on the vertical alignment film. An oriented retardation layer was formed. When the retardation value of the obtained vertically aligned retardation layer was measured at a wavelength of 550 nm, Re(550)=1 nm and Rth(550)=-75 nm. That is, the vertically aligned retardation layer was a positive C layer satisfying the relationship of nx≈ny<nz. In addition, since the retardation value at a wavelength of 550 nm of the cycloolefin-based resin film as the substrate is approximately 0, the optical properties of the vertically aligned retardation layer are not affected.

Subsequently, on the obtained vertically aligned retardation layer, a layer giving a retardation of λ/4 is formed in the same manner as in [Production of retardation film 2] to produce a laminate including retardation film 5. bottom. In this way, a laminate including the retardation film 5 was produced, in which the substrate, the vertical alignment film, the positive C layer, the alignment film, and the layer giving a retardation of λ/4 were laminated in this order. The puncture elastic modulus of the retardation film 5 was measured in the same manner as described above. Table 1 shows the puncture elastic modulus of the retardation film 5 .

[Preparation of adhesive layer]
Adhesive A: Sheet adhesive with a thickness of 5 μm (“NCF #L2” manufactured by Lintec Corporation) Adhesive B: Sheet adhesive with a thickness of 25 μm (“P-3132” manufactured by Lintec Corporation)

[Preparing protective film]
Protective film A: A film obtained by forming a hard coat layer with a thickness of 3 μm on a stretched film made of a norbornene resin with a thickness of 25 μm [manufactured by Nippon Paper Industries Co., Ltd. under the trade name “COP25ST-HC”
Protective film B: Triacetyl cellulose film with a thickness of 20 μm [trade name “ZRG20SL” manufactured by Fujifilm Corporation]
Protective film C: unstretched film made of triacetyl cellulose with a thickness of 25 μm

[Fabrication of front plate]
A front plate having hard coat layers on both sides of the base film was prepared. The base film was a polyimide film with a thickness of 50 μm, and the hard coat layer had a thickness of 10 μm.

[Example 1]
[Preparation of polarizing plate]
Polyvinyl alcohol film with a thickness of 20 μm (average degree of polymerization: about 2400, degree of saponification: 99.9 mol% or more) is uniaxially stretched by dry stretching to about 4 times, and furthermore, while maintaining tension, it is placed in pure water at 40 ° C. After being immersed for 40 seconds, it was dyed by being immersed in an aqueous solution of iodine/potassium iodide/water at a weight ratio of 0.052/5.7/100 at 28° C. for 30 seconds. After that, it was immersed in an aqueous solution of potassium iodide/boric acid/water at a weight ratio of 11.0/6.2/100 at 70° C. for 120 seconds. Subsequently, after washing with pure water at 8°C for 15 seconds, the film was dried at 60°C for 50 seconds and then at 75°C for 20 seconds while maintaining a tension of 300N. A polarizer having a thickness of 7 μm was obtained.

A water-based adhesive was applied to one surface of the polarizer, and the protective film A was attached. At this time, the protective film A was attached so that the stretching direction of the protective film A was 45 degrees with respect to the absorption axis of the polarizer.
A water-based adhesive was applied to the other surface of the polarizer, and the protective film B was attached. Then, it was dried to obtain a polarizing plate. The water-based adhesive is prepared by dissolving 3 parts of carboxyl group-modified polyvinyl alcohol [trade name "KL-318" obtained from Kuraray Co., Ltd.] in 100 parts of water. 1.5 parts of [Aqueous solution with a solid content concentration of 30%, trade name "Sumireze Resin 650 (30)" manufactured by Taoka Kagaku Kogyo Co., Ltd.] is added.

Adhesive A was laminated on the layer in which the polymerizable liquid crystal compound was cured in the laminate produced in [Preparation of Retardation Film 2]. Next, the base material was peeled off from the laminate, and the pressure-sensitive adhesive B was laminated on the surface exposed by peeling. In this manner, a retardation film 2 with double-sided pressure-sensitive adhesive, comprising the pressure-sensitive adhesive A, the layer in which the polymerizable liquid crystal compound was cured, the alignment film, and the pressure-sensitive adhesive B, was produced.

[Production of circularly polarizing plate]
On the protective film B of the polarizing plate, the retardation film 2 with double-sided adhesive was attached via the adhesive A of the retardation film 2 with double-sided adhesive. The slow axis of the layer in which the polymerizable liquid crystal compound was cured was 45 degrees with respect to the absorption axis of the polarizer and 90 degrees with respect to the stretching direction of the protective film A. Thus, the protective film A, the water-based adhesive layer, the polarizer, the water-based adhesive layer, the protective film B, the adhesive A, the layer in which the polymerizable liquid crystal compound is cured, the alignment film, and the circularly polarizing plate consisting of the adhesive B was made.

A circularly polarizing plate was cut into a rectangle with a size of 140 mm×70 mm so that the slow axis of the layer in which the polymerizable liquid crystal compound was cured was parallel to the long side. At this time, the stretching direction of the protective film A was parallel to the short side direction. The cut circularly polarizing plate was attached to a 0.4 mm-thick glass plate (manufactured by Corning, product number: EAGLE XG (registered trademark)) with adhesive B interposed therebetween.
Thus, samples for evaluation were produced.

[Example 2]
In Example 1, a circle was formed in the same manner as in Example 1, except that the laminate prepared in [Preparation of retardation film 3] was used instead of the laminate prepared in [Preparation of retardation film 2]. A polarizing plate was produced and a sample for evaluation was produced.

[Example 3]
In Example 1, a circle was formed in the same manner as in Example 1, except that the laminate prepared in [Preparation of retardation film 4] was used instead of the laminate prepared in [Preparation of retardation film 2]. A polarizing plate was produced and a sample for evaluation was produced.

[Example 4] (Comparison)
In Example 2, the slow axis of the layer in which the polymerizable liquid crystal compound is cured is 45 degrees with respect to the absorption axis of the polarizer, and the protective film is 0 degrees with respect to the stretching direction of the protective film A. A circularly polarizing plate was produced in the same manner as in Example 2, except that A was attached to the polarizer, and a sample for evaluation was produced. At this time, the stretching direction of the protective film A was parallel to the long side direction.

[Example 5]
In Example 1, a circle was formed in the same manner as in Example 1, except that the laminate prepared in [Preparation of retardation film 5] was used instead of the laminate prepared in [Preparation of retardation film 2]. A polarizing plate was produced and a sample for evaluation was produced.

[Example 6]
A circularly polarizing plate was produced in the same manner as in Example 1, except that the protective film B was not laminated during the production of the polarizing plate. Furthermore, the adhesive layer B was laminated on the protective film A. The front plate and the circularly polarizing plate were bonded together with the pressure-sensitive adhesive layer B interposed therebetween. Thus, a circularly polarizing plate consisting of the front plate, the adhesive layer B, the protective film A, the water-based adhesive layer, the polarizer, the adhesive A, the layer in which the polymerizable liquid crystal compound is cured, the alignment film, and the adhesive B is produced. made. Furthermore, in the same manner as in Example 1, a sample for evaluation was produced.

[Example 7]
[Composition for forming surface treatment layer]
A composition for forming a surface treatment layer was prepared by mixing the following components.
2.0 parts by mass of a dendrimer acrylate having an 18-functional acrylic group (Miramer SP1106, Miwon);
Urethane acrylate having a hexafunctional acrylic group (Miramer PU-620D, Miwon) 10.0 parts by mass,
8.0 parts by mass of an acrylate monomer having a trifunctional acrylic group (M340, Miwon);
Photopolymerization initiator (Irgacure-184, BASF) 2 parts by mass,
leveling agent (BYK-3530, BYK) 0.1 parts by mass,
Methyl ethyl ketone (MEK) 77.9 parts by mass

[Polarizer-forming composition]
(Polymerizable liquid crystal compound)
The polymerizable liquid crystal compound includes a polymerizable liquid crystal compound represented by formula (1-6) [hereinafter, also referred to as compound (1-6)] and a polymerizable liquid crystal compound represented by formula (1-7) [hereinafter, Also referred to as compound (1-7)] was used.

Compound (1-6) and compound (1-7) were prepared according to Lub et al. Recl. Trav. Chim. It was synthesized according to the method described in Pays-Bas, 115, 321-328 (1996).

(Dichroic dye)
As the dichroic dye, the azo dyes described in the examples of JP-A-2013-101328 represented by the following formulas (2-1a), (2-1b), and (2-3a) were used.

The composition for forming a polarizing layer includes 75 parts of compound (1-6), 25 parts of compound (1-7), and the above formulas (2-1a), (2-1b), and (2-3a) as dichroic dyes. ) 2.5 parts each of the azo dyes, 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369, manufactured by BASF Japan) as a polymerization initiator 6 parts by weight , and 1.2 parts of a polyacrylate compound (BYK-361N, manufactured by BYK-Chemie) as a leveling agent are mixed with 400 parts of toluene as a solvent, and the resulting mixture is stirred at 80 ° C. for 1 hour. bottom.

Protective film A was coated with the composition for forming a surface treatment layer. The coating film was dried at 80° C. for 5 minutes, and then irradiated with ultraviolet rays using a UV irradiation device so that the exposure amount was 500 mJ/cm ² (365 nm standard) to cure the coating film. SPOT CURE SP-7 manufactured by Ushio Inc. was used as the UV irradiation device. The thickness of the surface treatment layer was 10.0 μm.

On the surface treatment layer of the protective film A, the alignment film-forming composition used in the production of the retardation film 1 was applied by a bar coating method. The coating was dried at 80°C for 1 minute. Then, the coating film was irradiated with polarized UV light using the UV irradiation device and wire grid described above to impart alignment performance to the coating film. The exposure dose was 100 mJ/cm ² (365 nm standard). UIS-27132## (manufactured by Ushio Inc.) was used as the wire grid. Thus, an alignment film was formed. The thickness of the alignment film was 100 nm.

The polarizer-forming composition was applied onto the formed alignment film by a bar coating method. After the coating film was dried by heating at 100° C. for 2 minutes, it was cooled to room temperature. A polarizer was formed by irradiating the coating film with ultraviolet rays at an integrated light amount of 1200 mJ/cm ² (365 nm standard) using the above UV irradiation device. The thickness of the obtained polarizer was 3 μm. A composition containing polyvinyl alcohol and water was coated on the polarizer so as to have a thickness of 0.5 μm after drying, and dried at a temperature of 80° C. for 3 minutes to form a protective layer. Thus, a polarizing plate comprising the protective film A, the surface treatment layer, the alignment film, the polarizer, and the protective layer was produced.

A circularly polarizing plate was produced in the same manner as in Example 6 except that the above polarizing plate was used, and a sample for evaluation was produced. The evaluation sample includes the front plate, adhesive layer B, protective film A, surface treatment layer, alignment film, polarizer, protective layer, adhesive A, layer in which the polymerizable liquid crystal compound is cured, alignment film and adhesive B. I was prepared for this order.

[Example 8]
A circularly polarizing plate was produced and a sample for evaluation was produced in the same manner as in Example 7, except that the protective film C was used instead of the laminate of the protective film A and the surface treatment layer. The sample for evaluation comprises a front plate, adhesive layer B, protective film C, alignment film, polarizer, protective layer, adhesive A, layer in which polymerizable liquid crystal compound is cured, alignment film and adhesive B in this order. rice field.

[Example 9]
A circularly polarizing plate was produced and an evaluation sample was produced in the same manner as in Example 8, except that the front plate was not laminated. The evaluation sample was provided with a protective film C, an alignment film, a polarizer, a protective layer, an adhesive A, a layer in which a polymerizable liquid crystal compound was cured, an alignment film, and an adhesive B in this order.

[Comparative Example 1]
In Example 1, a circle was formed in the same manner as in Example 1, except that the laminate prepared in [Preparation of retardation film 1] was used instead of the laminate prepared in [Preparation of retardation film 2]. A polarizing plate was produced and a sample for evaluation was produced.

[Evaluation of hue before and after heat resistance test]
As a reflector, MIRO (5011GP) manufactured by ALANOD was prepared. This reflector is a specular reflector having a reflective surface formed by vapor deposition.

The evaluation sample was placed on the reflector. Reflection hues (a*, b*) were measured using a spectrophotometer (trade name: CM-2600d, manufactured by Konica Minolta Japan Co., Ltd.). The reflection hue is a value when the light source is D65, and was measured by the SCI method (including specular reflection light).

Specifically, point 5 shown in FIG. 3 was used as the measurement point. Nine points 5 shown in FIG. 3 are points in a region 5 mm inside from the edge of the circularly polarizing plate, and are positioned at intervals of about 30 mm in the short side direction and at intervals of about 65 mm in the long side direction.

The evaluation samples prepared in Examples 1 to 9 and Comparative Example 1 were measured for reflection hue before and after being stored in a dryer at a temperature of 80° C. for 168 hours. The absolute value of hue change Δa*b* at each point was calculated. The hue change value at each point was calculated based on the direction of hue change, and the difference between the maximum and minimum hue change values of each evaluation sample was defined as Δa*b* (MAX-MIN). The results are shown in Tables 2 and 3.

Δa* = a* (after heat resistance test) - a* (before heat resistance test)
Δb* = b* (after heat resistance test) - b* (before heat resistance test)
Δa*b*=[(Δa*) ² +(Δb*) ² ] ^1/2
The hue change value is Δa*b* when Δa* is 0 or more, and Δa*b*×−1 when Δa* is less than 0.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a circularly polarizing plate that includes a retardation film and that exhibits a small change in hue before and after being placed in a high-temperature environment, which is useful.

1 polarizing plate 2 retardation film 3 organic EL display element 4 front panel 5 point 10 polarizer
11, 12 Protective films 13, 14, 16 Adhesive layer 15 Adhesive layers 20, 21 Layers obtained by curing polymerizable liquid crystal compounds 100, 101, 102, 103 Circularly polarizing plates 104, 105, 106 Organic EL display device

Claims (6)

A circularly polarizing plate in which a polarizing plate and a retardation film are laminated via an adhesive layer,
The circularly polarizing plate has an adhesive layer on its surface,
The polarizing plate has a polarizer,
The retardation film is arranged between the polarizing plate and the pressure-sensitive adhesive layer,
The retardation film includes two retardation layers,
The retardation layer includes a layer in which a polymerizable liquid crystal compound is cured,
The retardation film has a puncture elastic modulus of 30 gf/mm or more and 150 gf/mm or less,
The shape of the circularly polarizing plate is substantially rectangular,
In the polarizing plate, a protective film is laminated on the surface of the polarizer opposite to the retardation film side,
The protective film is a stretched film,
The stretched direction of the protective film and the short side direction of the circularly polarizing plate are substantially parallel,
The puncture elastic modulus is an elastic modulus measured by a test in which a needle with a tip diameter of 1 mmφ and 0.5R is used and the puncture speed is 0.33 cm/sec. Circularly polarizing plate with a retardation film fixed between two plates with circular holes. 2. The circularly polarizing plate according to claim 1, wherein the polarizer has a thickness of 15 [mu]m or less. 3. The circularly polarizing plate according to claim 1, wherein the retardation film has a thickness of 25 [mu]m or less. 4. The circularly polarizing plate according to claim 1, wherein the polarizer is formed of a layer obtained by curing a liquid crystal compound. A circularly polarizing plate with a front plate, wherein the circularly polarizing plate according to any one of claims 1 to 4 and the front plate are laminated via an adhesive layer. A display device, wherein the circularly polarizing plate according to any one of claims 1 to 4 is laminated on a display element via the pressure-sensitive adhesive layer.

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