JP6815354B2 - Laminate - Google Patents

Description

The present invention relates to a laminate.

In recent years, image display devices typified by organic electroluminescence (hereinafter, also referred to as organic EL) display devices have rapidly become widespread. The organic EL display device is equipped with a circular polarizing plate including a polarizing film and a retardation film (λ / 4 plate, retardation value of about 140 nm). By arranging the circularly polarizing plate, it is possible to prevent reflection of external light and improve the visibility of the screen. The ability of the display device to prevent reflection of external light is directly linked to the ability to display black as the original black. The higher this performance, the higher the contrast of the display device.

The circular polarizing plate can be obtained by combining a polarizing film and an A plate.
The phase difference value of the A plate is apparently different when viewed from an oblique direction and when viewed from the front direction. Therefore, there is a problem that the color of the reflected light changes depending on the viewing direction of the screen, and the contrast of the display device is lowered.

It has been proposed to further combine a C plate in order to compensate for a change in the phase difference value depending on the viewing direction of this screen (Patent Document 1). The C plate can compensate for the phase difference when viewed from an oblique direction and can contribute to the improvement of contrast. The magnitude of the effect of compensation is determined by the relationship between the in-plane retardation value RoA of the A plate and the phase difference value RthC in the thickness direction of the C plate. In both cases of under-compensation and over-compensation, the reflected light may be colored, causing a decrease in contrast when viewed from an oblique direction. Conventionally, from the viewpoint of theoretical calculation, it has been considered that the phase difference value RthC in the thickness direction of the C plate required for ideal compensation is 1/2 of the in-plane phase difference value of the A plate. .. However, it cannot be said that a display device equipped with a circularly polarizing plate having a retardation film designed in this way achieves a contrast that does not necessarily depend on the viewing direction of the screen.

Japanese Unexamined Patent Publication No. 2016-40603

An object of the present invention is to provide a laminate provided with a circular polarizing plate capable of suppressing coloring of reflected light due to reflection of external light and imparting a good black display ability even when viewed from an oblique direction, and the laminate. It is to provide an organic EL display device provided with.

[1] A polarizing film, a retardation film, and a light reflecting layer are provided in this order.
The retardation film includes a first retardation film and a second retardation film.
The first retardation film has the characteristics represented by the formulas (1) to (3).
The second retardation film has the property represented by the formula (4).
The first retardation film and the second retardation film satisfy the relationship of the formula (5).
The light reflecting layer is a laminated body having the characteristics represented by the formula (6).
nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
nx ≒ ny <nz (4)
0.1 << | RthC (550) | / | RoA (550) | <0.5 (5)
45% <Yref <85% (6)
[In each equation, nx represents the refractive index in the slow axis direction in the film plane.
ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis.
nz represents the refractive index in the thickness direction of the film.
RoA (λ) represents the in-plane retardation value of the first retardation film at the wavelength λ nm.
RthC (λ) represents the retardation value in the thickness direction of the second retardation film at the wavelength λnm.
Yref represents the luminosity factor correction reflectance. ]
[2] A polarizing film, a retardation film, and a light reflecting layer are provided in this order.
The retardation film includes a first retardation film and a second retardation film.
The first retardation film has the characteristics represented by the formulas (1) to (3).
The second retardation film has the property represented by the formula (4).
The first retardation film and the second retardation film satisfy the relationship of the formula (7).
The light reflecting layer is a laminated body having the characteristics represented by the formula (8).
nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
nx ≒ ny <nz (4)
0.5 << | RthC (550) | / | RoA (550) | <1.0 (7)
85% ≤ Yref <100% (8)
[In each equation, nx represents the refractive index in the slow axis direction in the film plane.
ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis.
nz represents the refractive index in the thickness direction of the film.
RoA (λ) represents the in-plane retardation value of the first retardation film at the wavelength λ nm.
RthC (λ) represents the retardation value in the thickness direction of the second retardation film at the wavelength λnm.
Yref represents the luminosity factor correction reflectance. ]
[3] The laminate according to [1] or [2] is provided.
When observing from an oblique angle of 50 ° when displayed in black
The oblique hue difference, which is the distance in the a * b * plane between the reflected hue value at the in-plane angle at which the reflected hue value is maximized and the reflected hue value at an angle obtained by adding 90 ° to the in-plane angle, is less than 4. An organic electroluminescence display device.
[4] A polarizing film and a retardation film are provided.
The retardation film includes a first retardation film and a second retardation film.
The first retardation film has the characteristics represented by the formulas (1) to (3).
The second retardation film has the property represented by the formula (4).
The first retardation film and the second retardation film satisfy the relationship of the equation (5).
A circularly polarizing plate for bonding to a light reflecting layer having the characteristics represented by the formula (6).
nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
nx ≒ ny <nz (4)
0.1 << | RthC (550) | / | RoA (550) | <0.5 (5)
45% <Yref <85% (6)
[In each equation, nx represents the refractive index in the slow axis direction in the film plane.
ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis.
nz represents the refractive index in the thickness direction of the film.
RoA (λ) represents the in-plane retardation value of the first retardation film at the wavelength λ nm.
RthC (λ) represents the retardation value in the thickness direction of the second retardation film at the wavelength λnm.
Yref represents the luminosity factor correction reflectance. ]
[5] A polarizing film and a retardation film are provided.
The retardation film includes a first retardation film and a second retardation film.
The first retardation film has the characteristics represented by the formulas (1) to (3).
The second retardation film has the property represented by the formula (4).
The first retardation film and the second retardation film satisfy the relationship of the formula (7).
A circularly polarizing plate for bonding to a light reflecting layer having the characteristics represented by the formula (8).
nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
nx ≒ ny <nz (4)
0.5 << | RthC (550) | / | RoA (550) | <1.0 (7)
85% ≤ Yref <100% (8)
[In each equation, nx represents the refractive index in the slow axis direction in the film plane.
ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis.
nz represents the refractive index in the thickness direction of the film.
RoA (λ) represents the in-plane retardation value of the first retardation film at the wavelength λ nm.
RthC (λ) represents the retardation value in the thickness direction of the second retardation film at the wavelength λnm.
Yref represents the luminosity factor correction reflectance. ]

The laminated body of the present invention can suppress coloring of reflected light due to reflection of external light, and can impart good black display ability even when viewed from an oblique direction. The organic EL display device including the laminated body of the present invention can suppress the coloring of the reflected light due to the reflection of external light, and can exhibit a good black display ability even when viewed from an oblique direction.

It is an example of the schematic sectional view which shows the layer structure of a laminated body. It is the schematic for demonstrating the measurement of the oblique angle color difference.

<Laminated body>
The laminate of the present invention includes a polarizing film, a retardation film, and a light reflecting layer in this order. The polarizing film, the retardation film, the light reflecting layer, and other members can be laminated with each other via an adhesive layer. Examples of the adhesive layer include an adhesive layer and an adhesive layer described later.

Hereinafter, an example of the layer structure of the laminated body of the present invention will be described with reference to FIG. In FIG. 1, the adhesive layer for adhering the polarizing film 10 and the protective films 11 and 12, respectively, is not shown. The laminate 100 shown in FIG. 1 includes a polarizing plate in which a first protective film 11 is laminated on one surface of a polarizing film 10 and a second protective film 12 is laminated on the other surface of the polarizing film 10. The retardation film 2 and the light reflecting layer 16 have a layer structure in which they are laminated in this order.

The polarizing plate and the retardation film 2 are laminated via the pressure-sensitive adhesive layer 13, and the retardation film 2 and the light-reflecting layer 16 are laminated via the pressure-sensitive adhesive layer 14. In the retardation film 2, the first retardation film 20 and the second retardation film 21 are laminated via an adhesive layer 15. Further, the retardation film has, for example, an alignment film for orienting a polymerizable liquid crystal compound, a base film, and other retardation layers in addition to the first retardation film and the second retardation film. You may. The light reflecting layer 16 can be, for example, an electrode included in the organic EL display element. In this case, between the light reflecting layer 16 and the retardation film, a transparent or translucent electrode, a hole injection layer, a hole transport layer, an organic light emitting layer, a hole prevention layer, an electron transport layer, and an electron injection layer. It can have at least one layer selected from the group consisting of.

The stacking order of the first retardation film and the second retardation film is arbitrary. That is, the laminate of the present invention may include a polarizing film, a first retardation film, a second retardation film, and a light reflecting layer in this order, or a polarizing film, a second retardation film, and a first. The retardation film and the light reflecting layer may be provided in this order.

The laminated body can have a layer other than the layer shown in FIG. Examples of the layer that the laminate may further include include a front plate, a light-shielding pattern, and a touch sensor. The front plate can be arranged on the side of the polarizing plate opposite to the side on which the retardation film is laminated. The shading pattern can be arranged between the front plate and the laminate. The light-shielding pattern can be formed on the surface of the front plate on the polarizing plate side. The shading pattern is formed on the frame (non-display area) of the image display device so that the wiring of the image display device is not visible to the user. The touch sensor can be arranged between the front plate and the laminated body, between the retardation film and the light reflecting layer in the laminated body, and the like.

The shape of the laminate of the present invention is not particularly limited. When the laminate is substantially rectangular, the length of the long side is preferably 5 cm or more and 35 cm or less, more preferably 10 cm or more and 25 cm or less, and the length of the short side is 5 cm or more and 25 cm or less. It is preferably 6 cm or more and 20 cm or less.

The substantially rectangular shape means that the laminated body has a shape or a rounded shape in which at least one of the four corners (corners) of the main surface is cut off so as to have an obtuse angle. Or, a part of the end face perpendicular to the main surface has a recess (cutout) recessed in the in-plane direction, or a part of the main surface is circular, elliptical, polygonal, or a combination thereof. It means that it may have a perforated portion hollowed out in a shape.

The organic EL display device including the laminated body of the present invention preferably has an oblique color difference of less than 4, more preferably less than 3. The lower limit of the oblique color difference is not particularly limited, but is ideally 0. When the oblique color difference takes such a value, the tint of the reflected light of the organic EL display device can be made more uniform.

In the present specification, the oblique hue difference is the reflected hue value at the in-plane angle at which the reflected hue value becomes maximum when observed from an elevation angle of 50 ° with the organic EL display device displaying black, and the surface. It refers to the distance in the a * b * plane from the reflected hue value at an angle obtained by adding 90 ° to the internal angle. The in-plane angle at which the reflected hue value is maximized is the angle at which the reflected hue value is maximized by measuring the reflected hue value by changing the in-plane angle from 0 ° to 360 ° with the elevation angle as 50 °.

Specifically, the oblique color difference will be described with reference to FIG. FIG. 2A is a side view of the laminated body 100. As the reflected hue value for calculating the oblique hue difference, the value when observed from the direction 40 in which the elevation angle 30 is 50 ° is adopted. FIG. 2B is a view of the laminated body 100 from above (from the side opposite to the retardation film side with reference to the polarizer). The oblique hue difference was observed from the direction 42 of the angle obtained by adding 90 ° (in-plane angle 32) to the in-plane angle of the direction 41 and the reflected hue value when observed from the direction 41 in which the reflected hue value became maximum. The reflected hue value at that time is measured, and the distance between them in the a * b * plane is calculated from the following formula.
Oblique color difference = (Δa * ² + Δb * ² ) ^1/2

Regarding the reflected hue value when observed from the direction 41 in which the reflected hue value becomes maximum, a * is preferably -3 or more and 3 or less, and more preferably −1.5 or more and 1.5 or less. b * is preferably -3 or more and 3 or less, and more preferably -1.5 or more and 1.5 or less.

Regarding the reflected hue value when observed from the direction 42, which is the in-plane angle of the direction 41 plus 90 ° (angle 32), a * is preferably -3 or more and 3 or less, and −1.5 or more and 1 More preferably, it is 5.5 or less. b * is preferably -3 or more and 3 or less, and more preferably -1.5 or more and 1.5 or less.

<Polarizer>
In the present invention, the polarizing plate refers to a film composed of a polarizing film and a protective film bonded to one side or both sides of the polarizing film. The protective film included in the polarizing plate may have a surface treatment layer such as a hard coat layer, an antireflection layer, and an antistatic layer described later. The polarizing film and the protective film can be laminated, for example, via an adhesive layer or an adhesive layer. The members included in the polarizing plate will be described below.

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

As the polyvinyl alcohol-based resin, a saponified 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 another monomer copolymerizable with the vinyl acetate. 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, the term "(meth) acrylic" means at least one selected from acrylic and methacrylic. The same applies to "(meth) acryloyl", "(meth) acrylate" and the like.

The degree of saponification of the polyvinyl alcohol-based 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 can be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, preferably 1500 to 5000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726.

A film formed of such a polyvinyl alcohol-based resin is used as a raw film for a polarizing film. The method for forming a film of the polyvinyl alcohol-based resin is not particularly limited, and a known method is adopted. The thickness of the polyvinyl alcohol-based raw film is not particularly limited, but in order to reduce the thickness of the polarizing film to 15 μm or less, it is preferable to use a film having a thickness of 5 to 35 μm. More preferably, it is 20 μm or less.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing the dichroic dye, at the same time as dyeing, or after dyeing. If the uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before or during the cross-linking treatment. Moreover, uniaxial stretching may be performed in these a plurality of steps.

In uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched, or thermal rolls may be used to uniaxially stretch. Further, the uniaxial stretching may be a dry stretching performed in the atmosphere, or a wet stretching performed in a state where the polyvinyl alcohol-based resin film is swollen with 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 adopted. As the dichroic dye, iodine or a dichroic organic dye is used. The polyvinyl alcohol-based resin film is preferably immersed in water before the dyeing treatment.

As a cross-linking treatment after dyeing with a dichroic dye, a method of immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution 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 polarizing film 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 polarizing film is usually 2 μm or more, preferably 3 μm or more.

As the polarizing film, for example, as described in JP-A-2016-170368, a film in which a dichroic dye is oriented in a cured film in which a liquid crystal compound is polymerized may be used. As the dichroic dye, those having absorption in the wavelength range of 380 to 800 nm can be used, and it is preferable to use an organic dye. Examples of the dichroic dye include an azo compound. The liquid crystal compound is a liquid crystal compound that can be polymerized while being oriented, and can have a polymerizable group in the molecule. Further, as described in WO2011 / 024891, a polarizing film may be formed from a dichroic dye having a liquid crystal property.

The luminosity factor correction polarization degree of the polarizing film is preferably 90% or more, and more preferably 95% or more. The upper limit is not particularly limited, but is 99.9999% or less. Further, the transmittance of the polarizing film for correcting the luminosity factor is preferably 35% or more, and more preferably 40% or more. The upper limit is not particularly limited, but is 49.9% or less. When the laminate is provided with a polarizing film having such performance, the reflected light is less likely to leak, and the coloring can be made inconspicuous.

(2) Protective film The protective film laminated on one side or both sides of the polarizing film can be a translucent (preferably optically transparent) thermoplastic resin. The protective film is, for example, a polyolefin resin such as a chain polyolefin resin (polypropylene resin or the like) or a cyclic polyolefin resin (norbornen resin or the like); a cellulose resin such as triacetyl cellulose or diacetyl cellulose; polyethylene terephthalate. , Polybutylene terephthalate-based polyester resin; Polycarbonate resin; (Meta) acrylic resin such as methyl methacrylate-based resin; Polystyrene-based resin; Polyvinyl chloride-based resin; Acrylonitrile-butadiene-styrene-based resin; Acrylonitrile- Styrene resin; Polyvinyl acetate resin; Polyvinylidene chloride resin; Polyamide resin; Polyacetal resin; Modified polyphenylene ether resin; Polysulfone resin; Polyether sulfone resin; Polyallylate resin; Polyamiimide resin; It can be a film made of a polyimide resin or the like.

As the chain polyolefin resin, polyethylene resin (polyethylene resin which is a homopolymer of ethylene or a copolymer mainly composed of ethylene), polypropylene resin (polypropylene resin which is a homopolymer of propylene or propylene as a main component) are used. In addition to homopolymers of chain olefins such as (copolymers), copolymers composed of two or more kinds of chain olefins can be mentioned.

Cyclic polyolefin resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin is mentioned. Specific examples of the cyclic polyolefin resin include an open (co) polymer of a cyclic olefin, an addition polymer of a cyclic olefin, and a copolymer of a cyclic olefin and a chain olefin such as ethylene and propylene (typically). Is a random copolymer), a graft polymer obtained by modifying these with an unsaturated carboxylic acid or a derivative thereof, and a hydride thereof. Of these, a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer is preferably used as the cyclic olefin.

The polyester-based resin is a resin having an ester bond, excluding the following cellulose ester-based resin, and is generally composed of a polyvalent carboxylic acid or a polycondensate of a derivative thereof and a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylic acid. As the polyhydric alcohol, a divalent diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. A typical example of the polyester resin is polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol.

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

Cellulose ester-based resins are esters of cellulose and fatty acids. Specific examples of the cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. In addition, these copolymers and those in which a part of the hydroxyl group is modified with another substituent can also be mentioned. Among these, cellulose triacetate (triacetyl cellulose) is particularly preferable.

Polycarbonate-based resin is an engineering plastic composed of a polymer in which monomer units are bonded via a carbonate group.

The retardation value of the protective film may be appropriately controlled to a suitable value. In order to improve the visibility of the screen when the user wears polarized sunglasses or the like, the in-plane phase difference value at a wavelength of 550 nm may be set to 70 to 140 nm.

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

The protective film bonded to both sides of the polarizing film may be made of the same type of thermoplastic resin, or may be made of different types of thermoplastic resin. Further, the thickness may be the same or different. Further, it may have the same phase difference characteristic or may have different phase difference characteristics.

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

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

Examples of the water-based adhesive include an adhesive composed of a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. Of these, a water-based adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin is preferably used. The polyvinyl alcohol-based resin includes a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and a co-polymer of vinyl acetate and another monomer copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by saponifying the polymer, or a modified polyvinyl alcohol-based polymer in which the hydroxyl groups thereof are partially modified can be used. The water-based adhesive may contain a cross-linking agent such as an aldehyde compound (glioxal or the like), an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, or a polyvalent metal salt.

When a water-based adhesive is used, it is preferable to carry out a drying step for removing water contained in the water-based adhesive after the polarizing film and the protective film are bonded together. 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 active energy rays 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 the cationically polymerizable curable compound include an epoxy compound (a compound having one or two or more epoxy groups in the molecule) and an oxetane compound (one or two or more oxetane rings in the molecule). Compounds), or a combination thereof. Examples of the radically polymerizable curable compound include a (meth) acrylic compound (a compound having one or more (meth) acryloyloxy groups in the molecule) and a radically polymerizable double bond. Other vinyl compounds or combinations thereof can be mentioned. A cationically 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 the polarizing film and the protective film are bonded together, a surface activation treatment may be applied to at least one of these bonding surfaces in order to enhance the adhesiveness. The surface activation treatment includes dry treatment such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionization active ray treatment (ultraviolet ray treatment, electron beam treatment, etc.). Wet treatments such as ultrasonic treatment using a solvent such as water or acetone, saponification treatment, and anchor coating treatment can be mentioned. These surface activation treatments may be performed alone or in combination of two or more.

When the protective films are bonded to both sides of the polarizing film, the adhesive for bonding these protective films may be the same type of adhesive or different types of adhesives.

<Phase difference film>
The retardation film includes a first retardation film and a second retardation film. Further, the retardation film may include a substrate, an alignment film, and other retardation layers described later.

The first retardation film has the characteristics represented by the formulas (1) to (3). The first retardation film can be a positive A plate and can be a λ / 4 plate. Further, the first retardation film exhibits anti-wavelength dispersibility. By providing such a first retardation film, it is possible to suppress the coloring of the reflected light. The first retardation film can be arranged so that its slow axis is approximately 45 ° with respect to the absorption axis of the polarizing film. Approximately 45 ° means 45 ± 5 °.

nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
In the formulas (1) to (3), nx represents the refractive index in the slow axis direction in the film plane, and ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis. nz represents the refractive index in the thickness direction of the film. RoA (λ) represents the in-plane retardation value of the first retardation film at a wavelength of λ nm.

ny≈nz includes not only the case where ny and nz are completely equal, but also the case where ny and nz are substantially equal. Specifically, if the magnitude of the difference between ny and nz is within 0.01, it can be said that ny and nz are substantially equal.

RoA (λ) can be calculated from the refractive index n (λ) at the wavelength λ nm and the thickness d based on the following formula.
RoA (λ) = [nx (λ) -ny (λ)] × d
RoA (450) / RoA (550) represents the wavelength dispersibility of the first retardation film, and is preferably 0.92 or less.

Regarding the in-plane retardation value RoA (λ) of the first retardation film at a wavelength of λ nm, RoA (450) is preferably 100 nm or more and 135 nm or less, and RoA (550) is 137 nm or more and 145 nm or less. Is preferable, and RoA (650) is preferably 137 or more and 165 or less.

The second retardation film has the characteristics represented by the formula (4). The second retardation film can be a positive C plate. By providing such a second retardation film, it is possible to suppress the coloring of the reflected light.
nx ≒ ny <nz (4)
In the formula (4), nx represents the refractive index in the slow axis direction in the film plane, ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis, and nz represents the refractive index of the film. Represents the refractive index in the thickness direction.

nx≈ny includes not only the case where nx and ny are completely equal, but also the case where nx and ny are substantially equal. Specifically, if the magnitude of the difference between nx and ny is within 0.01, it can be said that nx and ny are substantially equal.

Although it depends on the reflection characteristics of the light reflecting layer described later, specifically, the retardation value in the thickness direction of the second retardation film is preferably −150 nm or more and 0 nm or less at a wavelength of 550 nm, and is −90 nm or more. It is more preferably −20 nm or less.

The retardation film may include one or more layers having a retardation other than the first retardation film and the second retardation film (hereinafter, may be referred to as other retardation layers). Examples of other retardation layers include a touch sensor included in the display element, a sealing layer of the light emitting element, a base film of the light emitting element, and the like. The other retardation layer is arranged between the polarizing film and the light reflection layer, and preferably is arranged between the second retardation film and the light reflection layer.

The other retardation layer may be an A plate, but can usually be a C plate. The other retardation layer may have the characteristics represented by the equation (9). That is, the other retardation layer can be a negative C plate.
nx ≒ ny> nz (9)

nx≈ny includes not only the case where nx and ny are completely equal, but also the case where nx and ny are substantially equal. Specifically, if the magnitude of the difference between nx and ny is within 0.01, it can be said that nx and ny are substantially equal.

The retardation film including at least the first retardation film and the second retardation film satisfies the following formula (5) or (7) depending on the luminosity factor correction reflectance of the light reflecting layer.
0.1 << | RthC (550) | / | RoA (550) | <0.5 (5)
0.5 << | RthC (550) | / | RoA (550) | <1.0 (7)
In the formulas (5) and (7), RoA (λ) represents the in-plane retardation value at the wavelength λnm of the first retardation film, and RthC (λ) represents the wavelength λnm of the second retardation film. Represents the phase difference value in the thickness direction in.

RthC (λ) can be calculated from the refractive index n (λ) at the wavelength λ nm and the thickness d based on the following formula.
RthC (λ) = {[nx (λ) + ny (λ)] / 2-nz} × d

RthC (450) / RthC (550) represents the wavelength dispersibility of the second retardation film, and is preferably 1.5 or less, more preferably 1.1 or less.

As a result of diligent studies by the inventor of the above equations (5) and (7), the optimum compensation value in an actual display device may differ from the conventional ideal compensation value depending on the reflection characteristics of the light reflecting layer. It is based on what has become clear.

When the light reflecting layer satisfies the characteristics of the formula (6) described later, the retardation film preferably satisfies the relationship of the formula (5). That is, the ratio of the retardation value RthC in the thickness direction of the second retardation film to the in-plane retardation value of the first retardation film was conventionally considered to be able to achieve ideal compensation. Less than 5. | RthC (550) | / | RoA (550) | is preferably more than 0.1 and less than 0.5, and more preferably 0.2 or more and 0.4 or less. When the retardation film satisfies the above relationship, it is possible to suppress the coloring of the reflected light when viewed from an oblique direction.

On the other hand, when the light reflecting layer satisfies the characteristics of the formula (8) described later, the retardation film preferably satisfies the relationship of the formula (7). That is, the ratio of the retardation value RthC in the thickness direction of the second retardation film to the in-plane retardation value of the first retardation film was conventionally considered to be able to achieve ideal compensation. Greater than 5. | RthC (550) | / | RoA (550) | is preferably more than 0.5 and less than 1.0, and more preferably 0.55 or more and 0.8 or less. When the retardation film satisfies the above relationship, it is possible to suppress the coloring of the reflected light when viewed from an oblique direction.

The first retardation film and the second retardation film forming the retardation film can be formed from the composition containing the above-mentioned thermoplastic resin film and the polymerizable liquid crystal compound. The first retardation film and the second retardation film are preferably formed from a composition containing a polymerizable liquid crystal compound. Examples of the layer formed from the composition containing the polymerizable liquid crystal compound include a layer obtained by curing the polymerizable liquid crystal compound.

The relationship between equations (1) to (3) satisfied by the first retardation film, the relationship between equations (4) satisfied by the second retardation film, and the equation (5) or equation (7) satisfied by the retardation film. For example, the type and compounding ratio of the thermoplastic resin and the polymerizable liquid crystal compound forming the first retardation film and the second retardation film can be adjusted, and the first retardation film and the second position can be adjusted. It is controlled by adjusting the thickness of the retardation film.

The cured layer of the polymerizable liquid crystal compound is formed on, for example, an alignment film provided on the base material. The base material has a function of supporting the alignment film and may be a long base material. This substrate can function as a releasable support and support a retardation film for transfer. Further, it is preferable that the surface has an adhesive force that can be peeled off. Examples of the base material include a resin film exemplified as a material for the protective film.

The thickness of the base material is not particularly limited, but is preferably in the range of, for example, 20 μm or more and 200 μm or less. When the thickness of the base material is 20 μm or more, strength is imparted. On the other hand, when the thickness is 200 μm or less, when the base material is cut to obtain a single-wafer base material, an increase in processing waste and wear of the cutting blade can be suppressed.

The base material may be subjected to various blocking prevention treatments. Examples of the blocking prevention treatment include an easy-adhesion treatment, a treatment of kneading a filler and the like, an embossing treatment (knurling treatment) and the like. By applying such a blocking prevention treatment to the base material, it is possible to effectively prevent the base materials from sticking to each other when the base material is wound, so-called blocking, and to manufacture an optical film with high productivity. Is possible.

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

The alignment film is not limited to the vertical alignment film, and may be an alignment film for horizontally aligning the molecular axis of the polymerizable liquid crystal compound, or may be an alignment film for tilting the molecular axis of the polymerizable liquid crystal compound. .. A horizontal alignment film can be used when the first retardation film is produced, and a vertically alignment film can be used when the second retardation film is produced. The alignment film has solvent resistance that does not dissolve due to coating of a composition containing a polymerizable liquid crystal compound, which will be described later, and heat resistance in heat treatment for removing the solvent and aligning the liquid crystal compound. preferable. Examples of the alignment film include an alignment film containing an orientation polymer, a photo-alignment film, and a grub alignment film that forms an uneven pattern or a plurality of grooves on the surface to align. The thickness of the alignment film is usually in the range of 10 nm to 10000 nm, preferably in the range of 10 nm to 1000 nm, more preferably in the range of 500 nm or less, and further preferably in the range of 10 nm to 200 nm.

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, and a conventionally known monofunctional or polyfunctional (meth) acrylate-based monomer is used under a polymerization initiator. A cured product or the like that has been cured can be used. Specifically, examples of the (meth) acrylate-based monomer include 2-ethylhexyl acrylate, cyclohexyl acrylate, diethylene glycol mono2-ethylhexyl ether acrylate, diethylene glycol monophenyl ether acrylate, tetraethylene glycol monophenyl ether acrylate, and trimethyl propantriacrylate. , 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 can be exemplified. The resin may be one of these or a mixture of two or more.

The type of the polymerizable liquid crystal compound used in the present embodiment is not particularly limited, but 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. it can. Further, there are a low molecular weight type and a high molecular weight type, respectively. The polymer generally refers to a polymer having a degree of polymerization of 100 or more (Polymer Physics / Phase Transition Dynamics, Masao Doi, 2 pages, Iwanami Shoten, 1992).

In this embodiment, any polymerizable liquid crystal compound can be used. Further, two or more kinds of rod-shaped liquid crystal compounds, two or more kinds of disc-shaped liquid crystal compounds, or a mixture of rod-shaped liquid crystal compounds and disc-shaped liquid crystal compounds may be used.

As the rod-shaped liquid crystal compound, for example, those described in claim 1 of JP-A-11-513019 or paragraphs [0026] to [00998] of JP-A-2005-289980 are preferably used. Can be done. As the disk-shaped 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 preferable. Can be used for.

Two or more kinds 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 cured layer of the polymerizable liquid crystal compound 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.

The polymerizable liquid crystal compound has a polymerizable group capable of carrying out 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 the polymerizable group include a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, the (meth) acryloyl group is preferable. The (meth) acryloyl group is a concept that includes both a meta-acryloyl group and an acryloyl group.

The cured layer of the polymerizable liquid crystal compound can be formed by applying a composition containing the polymerizable liquid crystal compound, for example, on an alignment film, as will be described later. The composition may contain components other than the above-mentioned polymerizable liquid crystal compound. For example, the composition preferably contains a polymerization initiator. As the polymerization initiator used, for example, a thermal polymerization initiator or a photopolymerization initiator is selected depending on the type of the polymerization reaction. For example, examples of the photopolymerization initiator include an α-carbonyl compound, an acyloin ether, an α-hydrocarbon-substituted aromatic acyloin compound, a polynuclear quinone compound, and a combination of a triarylimidazole dimer and a p-aminophenyl ketone. 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.

Further, the composition may contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Among them, a polyfunctional radically polymerizable monomer is preferable.

The polymerizable monomer is preferably one that can be copolymerized with the above-mentioned polymerizable liquid crystal compound. Specific examples of the polymerizable monomer include those described in paragraphs [0018] to [0020] in JP-A-2002-296423. 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. Examples of the surfactant include conventionally known compounds. Among them, fluorine-based compounds are particularly preferable. Specific examples of the surfactant include the compounds described in paragraphs [0028] to [0056] in JP 2001-330725, and paragraphs [0069] to [0126] in Japanese Patent Application No. 2003-295212. ] The compounds described in.

In addition, the composition may contain a solvent, and an organic solvent is preferably used.
Examples of the organic solvent include amide (eg, N, N-dimethylformamide), sulfoxide (eg, dimethyl sulfoxide), heterocyclic compound (eg, pyridine), hydrocarbon (eg, benzene, hexane), alkyl halide (eg, 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 preferable. Further, two or more kinds of organic solvents may be used in combination.

Further, the composition includes vertical alignment promoters such as a polarizing film interface side vertical alignment agent and an air interface side vertical alignment agent, and horizontal alignment promotion such as a polarizing film interface side horizontal alignment agent and an air interface side horizontal alignment agent. Various orienting agents such as agents may be included. Further, the composition may contain an adhesion improver, a plasticizer, a polymer and the like in addition to the above components.

In the present embodiment, the thickness of the first retardation film and the second retardation film can be 0.1 μm or more and 5 μm or less. When the thickness of the first retardation film and the second retardation film is within the above range, sufficient durability can be obtained, which can contribute to thinning of the laminated body. As a matter of course, the thickness of the first retardation film and the second retardation film is a desired layer such as a layer giving a phase difference of λ / 4, a layer giving a phase difference of λ / 2, or a positive C plate. It can be adjusted so that an in-plane retardation value and a thickness direction retardation value can be obtained.

When the retardation film contains two layers in which the polymerizable liquid crystal compound is cured as the first retardation film and the second retardation film, the layers in which the polymerizable liquid crystal compound is cured are prepared on the alignment film, respectively. , A retardation film can be produced by laminating both via an adhesive layer or an adhesive layer. After laminating both, the base material 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.

<Light reflection layer>
The light reflecting layer is a layer that reflects light incident on the laminated body, and can typically include an electrode included in the organic EL display element. The organic EL display element has a thin film structure in which an organic light emitting material layer is sandwiched between a pair of electrodes facing each other. Electrons are injected into the organic light emitting material layer from one electrode, and holes are injected from the other electrode, so that the electrons and holes are combined in the organic light emitting material layer to perform self-emission. Compared with a liquid crystal display element or the like that requires a backlight, it has the advantages of better visibility, thinner size, and low DC voltage drive.

The material of the light reflecting layer is not limited as long as it satisfies the formula (6) or the formula (8). The light reflecting layer can be formed of metals such as gold, silver, copper, iron, nickel, chromium, molybdenum, titanium, aluminum, and alloys thereof.

The light reflecting layer satisfies the following formula (6) or formula (8) depending on the characteristics of the retardation film.
45% <Yref <85% (6)
85% ≤ Yref <100% (8)
In the formulas (6) and (8), Yref represents the luminosity factor correction reflectance.

Yref is a reflectance measured by the SCI method including specularly reflected light, and is a reflectance corrected for luminosity factor by the color matching function y (λ) (JIS Z 8701). Yref can be measured by a spectrophotometer.

As described above, when the retardation film satisfies the relationship of the formula (5), the light reflecting layer satisfies the characteristics represented by the formula (6), and when the retardation film satisfies the relationship of the formula (7), the light is emitted. The reflective layer satisfies the characteristics represented by the formula (8). By combining such a retardation film and a light reflecting layer, it is possible to suppress coloring of the reflected light when viewed from an oblique direction. In the formula (6), the Yref is preferably 45% or more and 80% or less, and in the formula (8), the Yref is preferably 90% or more and 99.9% or less, and more preferably 94% or more and 99.9% or less. Is.

The light-reflecting layer preferably has a reflectance of 10% or more and 80% or less, and more preferably 15% or more and 80% or less, as measured by the SCE method excluding the specularly reflected light. Setting the reflectance measured by the SCE method in such a range can contribute to reducing the increase in light intensity at a specific elevation angle by making the specularly reflected light relatively inconspicuous. The reflectance measured by the SCE method can be measured by a spectrocolorimeter.

<Adhesive layer>
The pressure-sensitive adhesive layer can be used to laminate the members of the laminate together. When the light reflecting layer includes an electrode included in the organic EL display element, the organic EL display element and the retardation film may be laminated via an adhesive layer. The pressure-sensitive adhesive layer can be composed of a pressure-sensitive adhesive composition containing a resin as a main component, such as (meth) acrylic-based, rubber-based, urethane-based, ester-based, silicone-based, and polyvinyl ether-based. Among them, a pressure-sensitive adhesive composition using a (meth) acrylic resin having excellent transparency, weather resistance, heat resistance and the like as a base polymer is preferable. The pressure-sensitive adhesive composition may be an active energy ray-curable type or a thermosetting type. The thickness of the pressure-sensitive adhesive layer is usually 3 to 30 μm, preferably 3 to 25 μm.

Examples of the (meth) acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2- (meth) acrylate. A polymer or copolymer containing one or more (meth) acrylic acid esters such as ethylhexyl as a monomer is preferably used. It is preferable that the base polymer is copolymerized with a polar monomer. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl (). Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as meta) acrylate.

The pressure-sensitive adhesive composition may contain only the above-mentioned base polymer, but usually further contains a cross-linking agent. The cross-linking agent is a divalent or higher metal ion that forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound that forms an amide bond with a carboxyl group; poly. Epoxy compounds and polyols that form an ester bond with a carboxyl group; polyisocyanate compounds that form an amide bond with a carboxyl group are exemplified. Of these, polyisocyanate compounds are preferable.

<Front plate>
The front plate can be arranged on the visible side of the polarizing plate. The front plate can be laminated on the polarizing plate via the adhesive layer. Examples of the adhesive layer include the above-mentioned adhesive layer and adhesive layer.

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

The front plate, which includes a hard coat layer on at least one surface of the resin film, can have a flexible property rather than being rigid like existing glass. The thickness of the hard coat layer is not particularly limited and may be, for example, 5 to 100 μm.

As the resin film, cycloolefin-based derivatives having a unit of a monomer containing cycloolefin such as norbornene or polycyclic norbornene-based monomer, 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, polyacrylic, polyimide, polyamideimide, polyethersulfone, polysulfone, polyethylene, Polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyether ketone, polyether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate , Polyethylene, a film made of a polymer such as epoxy. As the resin film, an unstretched uniaxial or biaxially stretched film can be used. Each of these polymers can be used alone or in combination of two or more. As the resin film, a polyamideimide film or polyimide film having excellent transparency and heat resistance, a uniaxial or biaxially stretched polyester film, a cycloolefin derivative film having excellent transparency and heat resistance and capable of adapting to a large film size. , Polymethylmethacrylate films and triacetylcellulose and isobutylester cellulose films that are transparent and not optically anisotropic are preferred. The thickness of the resin film may be 5 to 200 μm, preferably 20 to 100 μm.

<Shading pattern>
The light-shielding pattern (bezel) can be formed on the display element side of the front plate. The shading pattern can hide each wiring of the display device so that it cannot be seen by the user. The color and / or material of the light-shielding pattern is not particularly limited, and can be formed of a resin substance having various colors such as black, white, and gold. In one embodiment, the thickness of the shading pattern may be 2 μm to 50 μm, preferably 4 μm to 30 μm, and more preferably 6 μm to 15 μm. Further, in order to suppress the mixing of air bubbles due to the step between the light-shielding pattern and the display unit and the visibility of the boundary portion, the light-shielding pattern can be given a shape.

<Manufacturing method of laminated body>
The manufacturing method of the laminated body will be described by taking the laminated body 100 shown in FIG. 1 as an example. The laminate 100 is manufactured, for example, by sequentially laminating a polarizing plate, a retardation film 2, and a light reflecting layer 16 via adhesive layers 13 and 14.

The polarizing plate can be manufactured by laminating the polarizing film 10 and the protective films 11 and 12 via an adhesive layer, respectively. The polarizing plate may be manufactured by preparing a long member, laminating the respective members by roll-to-roll, and then cutting the polarizing plate into a predetermined shape, or cutting each member into a predetermined shape. After that, they may be pasted together. Next, the pressure-sensitive adhesive layer 13 formed on the release film is laminated on the protective film 12.

The retardation film 2 can be manufactured, for example, as follows. An alignment film is formed on the base material, and a coating liquid containing a polymerizable liquid crystal compound is applied onto the alignment film. With the polymerizable liquid crystal compound oriented, the polymerizable liquid crystal compound is cured by irradiating it with active energy rays. In this way, a film including the first retardation film 20 is produced. Similarly, a film including the second retardation film 21 is produced.

An adhesive layer 15 is formed on the first retardation film 20 or the second retardation film, and the film provided with the first retardation film 20 and the film provided with the second retardation film 21 are bonded together. Next, the base film or the base film and the alignment film are peeled off to prepare a retardation film 2. The retardation film 2 may be manufactured by preparing long members, laminating the members by roll-to-roll, and then cutting the members into a predetermined shape, or forming each member into a predetermined shape. After cutting, they may be pasted together. The retardation film 2 may be obtained by forming a second retardation film directly on the first retardation film. That is, the adhesive layer 15 can be omitted.

The release film on the pressure-sensitive adhesive layer 13 is peeled off, and the obtained polarizing plate and the retardation film 2 are bonded to each other via the exposed pressure-sensitive adhesive layer 13. The film thus obtained can function as a circular polarizing plate. When the light reflecting layer 16 includes an electrode included in the organic EL display element, the laminated body 100 of the present invention is manufactured by laminating the circular polarizing plate on the organic EL display element. The circularly polarizing plate is laminated on the organic EL display element including the light reflecting layer 16 via, for example, the pressure-sensitive adhesive layer 14.

<Use>
The laminate of the present invention can be used in various display devices. The display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. Examples of the display device include a liquid crystal display device, an organic EL display device, an inorganic electroluminescence (hereinafter, also referred to as inorganic EL) display device, an electron emission display device (for example, an electric field emission display device (also referred to as FED), and a surface electric field emission display. Device (also called SED)), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection type display device (for example, grating light valve (GLV) display device, digital micromirror device (DMD)) (Also referred to as), a piezoelectric ceramic display, and the like. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, and the like. The laminate of the present invention is particularly organic. It can be particularly effectively used for an EL display device or an inorganic EL display device.

In particular, the organic EL display device including the laminate of the present invention can suppress the coloring of the reflected light due to the reflection of external light, and can exhibit a good black display ability even when viewed from an oblique direction.

Hereinafter, the present invention will be described in more detail with reference to Examples. In addition, "%" and "part" in an example mean mass% and mass part unless otherwise specified.
(1) Film thickness measurement method:
The thickness of the film was measured using an ellipsometer M-220 manufactured by JASCO Corporation or a contact type film thickness meter (MH-15M manufactured by Nikon Corporation, counter TC101, MS-5C).

(2) Measurement method of phase difference value:
The phase difference value in the thickness direction and the in-plane phase difference value were measured using a KOBRA-WPR manufactured by Oji Measuring Instruments Co., Ltd. or an ellipsometer M-220 manufactured by JASCO Corporation.

(3) Reflected hue value observed from an elevation angle of 8 °:
The measurement was performed using CM-2600d, which is a spectrocolorimeter manufactured by Konica Minolta Co., Ltd.

(4) Reflected hue value observed from an elevation angle of 50 °:
The measurement was performed by the display evaluation system DMS803 manufactured by Instrument Systems GmbH.

[Preparation of light reflecting layer]
The following five types of light reflecting layers were used. Each light reflecting layer had a flat reflection spectrum, and white or silver reflected light could be visually recognized.
Light Reflecting Layer 1: NTK SUS 304B, which is a SUS plate manufactured by Nippon Metal Industry Co., Ltd.
Light-reflecting layer 2: The surface of the light-reflecting layer 1 is chrome-plated.
Light-reflecting layer 3: The glossy surface of My Foil Thick 50, which is an aluminum foil manufactured by UACJ Corporation.
Light Reflective Layer 4: Non-glossy surface of My Foil Thick 50, which is an aluminum foil manufactured by UACJ Corporation.
Light-reflecting layer 5: MIRO5 5011GP, which is an aluminum-deposited reflector manufactured by Alanod as a high-reflectance reflector.

The reflection characteristics of each light reflecting layer are as shown in the table below. Both reflectances are luminosity-corrected. The measurement was performed at an elevation angle of 8 ° using a CM-2600d spectrophotometer manufactured by Konica Minolta Co., Ltd.

[Preparation of Circular Polarizing Plate 1]
[Preparation of composition for forming horizontal alignment film]
Five parts (weight average molecular weight: 30,000) of a photo-oriented material having the following structure and 95 parts of cyclopentanone (solvent) were mixed. The obtained mixture was stirred at 80 ° C. for 1 hour to obtain a composition for forming a horizontal alignment film.

[Preparation of composition for forming vertical alignment film]
Sun Ever SE610 manufactured by Nissan Chemical Industries, Ltd. was used.

[Preparation of composition for forming horizontally oriented liquid crystal cured film]
A polymerizable liquid crystal compound A and a polymerizable liquid crystal compound B were used to form a horizontally oriented liquid crystal cured film (first retardation film). The polymerizable liquid crystal compound A was produced by the method described in JP-A-2010-31223. Further, the polymerizable liquid crystal compound B was produced according to the method described in JP-A-2009-173893. The molecular structure of each is shown below.

[Polymerizable liquid crystal compound A]

[Polymerizable liquid crystal compound B]

The polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B were mixed at a mass ratio of 90:10. 1.0 part of leveling agent (F-556; manufactured by DIC Corporation) and 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) as a polymerization initiator with respect to 100 parts of the obtained mixture. 6 parts of butane-1-one (Irgacure 369, manufactured by BASF Japan KK) 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 composition for forming a horizontally oriented liquid crystal cured film.

[Preparation of composition for forming vertically oriented liquid crystal cured film]
In order to form a vertically oriented liquid crystal cured film (second retardation film), a composition was prepared by the following procedure. To 100 parts of Pariocolor LC242 (registered trademark of BASF), which is a polymerizable liquid crystal compound, 0.1 part of F-556 was added as a leveling agent, and 3 parts of Irgacure 369 was added as a polymerization initiator. Cyclopentanone was added so that the solid content concentration was 13% to obtain a composition for forming a vertically oriented liquid crystal cured film.

[Preparation of polarizing plate]
A polyvinyl alcohol (PVA) film having an average degree of polymerization of about 2,400, a saponification degree of 99.9 mol% or more, and a thickness of 75 μm was prepared. After immersing the PVA film in pure water at 30 ° C, it was immersed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.02 / 2/100 at 30 ° C to perform iodine dyeing (iodine dyeing step). .. The PVA film that had undergone the iodine dyeing step was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. to perform boric acid treatment (boric acid treatment step). .. The PVA film that had undergone the boric acid treatment step was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizing film in which iodine was adsorbed and oriented on polyvinyl alcohol. The PVA film was stretched in the iodine dyeing step and the boric acid treatment step. The total draw ratio of the PVA film was 5.3 times. The thickness of the obtained polarizing film was 27 μm.

The polarizing film and the saponified triacetyl cellulose (TAC) film (KC4UYTAC thickness 40 μm manufactured by Konica Minolta Co., Ltd.) were bonded together with a nip roll via an aqueous adhesive. While maintaining the tension of the obtained laminate at 430 N / m, it was dried at 60 ° C. for 2 minutes to obtain a polarizing plate having a TAC film as a protective film on one side. The water-based adhesive is 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Co., Ltd., "Kuraray Poval KL318"), and water-soluble polyamide epoxy resin (Taoka Chemical Industry Co., Ltd., "Smiley's Resin 650". , An aqueous solution having a solid content concentration of 30%] 1.5 parts was added to prepare the mixture.

The optical characteristics of the obtained polarizing plate were measured. The measurement was carried out with a spectrophotometer (“V7100”, manufactured by JASCO Corporation) using the polarizing film surface of the polarizing plate obtained above as an incident surface. The absorption axis of the polarizing plate coincides with the stretching direction of polyvinyl alcohol, and the obtained polarizing plate has a luminosity factor correction single transmittance of 42.3%, a luminosity factor correction polarization degree of 99.996%, and a single hue a. It was −1.0, and the single hue b was 2.7.

[Preparation of retardation film]
Corona treatment was carried out on a cyclic olefin resin (COP) film (ZF-14-50) manufactured by Nippon Zeon Corporation. The corona treatment was performed using TEC-4AX manufactured by Ushio, Inc. The corona treatment was performed once under the conditions of an output of 0.78 kW and a processing speed of 10 m / min. The composition for forming a horizontal alignment film was applied to a COP film with a bar coater, and dried at 80 ° C. for 1 minute. A polarized UV irradiator (“SPOT CURE SP-9”, manufactured by Ushio Denki Co., Ltd.) was used for the coating film at an axial angle of 45 ° so that the integrated light intensity at a wavelength of 313 nm was 100 mJ / cm ² . Polarized UV exposure was performed. The film thickness of the obtained horizontal alignment film was 100 nm.

Subsequently, the composition for forming a horizontally oriented liquid crystal cured film was applied to the horizontally oriented film using a bar coater, and dried at 120 ° C. for 1 minute. Irradiate the coating film with ultraviolet rays (in a nitrogen atmosphere, integrated light intensity at a wavelength of 365 nm: 500 mJ / cm ² ) using a high-pressure mercury lamp (“Unicure VB-15201BY-A”, manufactured by Ushio Denki Co., Ltd.). A horizontally oriented liquid crystal cured film (first retardation film) was formed. The film thickness of the horizontally oriented liquid crystal cured film was 2.3 μm.

An adhesive layer was laminated on the horizontally oriented liquid crystal cured film. A film composed of a COP film, an alignment film, and a horizontally oriented liquid crystal cured film was bonded to glass via the pressure-sensitive adhesive layer. The COP film was peeled off to obtain a sample for measuring the retardation value.
As a result of measuring the phase difference value RoA (λ) at each wavelength, RoA (450) = 121 nm, RoA (550) = 142 nm, RoA (650) = 146 nm, RoA (450) / RoA (550) = 0.85, RoA (650) / RoA (550) = 1.03, and the horizontally oriented liquid crystal cured film showed reverse wavelength dispersibility. The horizontally oriented liquid crystal cured film was a positive A plate satisfying the relationship of nx> ny≈nz.
As a result of measuring the phase difference value RthA (λ) at each wavelength, it was RthA (450) = 61 nm, RthA (550) = 71 nm, and RthA (650) = 73 nm.

[Preparation of vertically oriented liquid crystal cured film]
Corona treatment was performed on the horizontally oriented liquid crystal cured film in the film composed of the COP film, the oriented film, and the horizontally oriented liquid crystal cured film prepared above. The conditions for corona treatment were the same as above. The composition for forming a vertically oriented film was applied on the horizontally oriented liquid crystal cured film with a bar coater and dried at 80 ° C. for 1 minute to obtain a vertically oriented film. The film thickness of the obtained vertically oriented film was 50 nm.

The composition for forming a vertically oriented liquid crystal cured film was applied to the vertically aligned film using a bar coater, and dried at 90 ° C. for 120 seconds. Irradiate the coating film with ultraviolet rays (in a nitrogen atmosphere, integrated light intensity at a wavelength of 365 nm: 500 mJ / cm ² ) using a high-pressure mercury lamp (“Unicure VB-15201BY-A”, manufactured by Ushio Denki Co., Ltd.). A vertically oriented liquid crystal cured film (second retardation film) was formed. In this way, a film composed of a COP film, a horizontally aligned film, a horizontally oriented liquid crystal cured film, a vertically aligned film, and a vertically oriented liquid crystal cured film was obtained. The film thickness of the vertically oriented liquid crystal cured film was 0.1 μm.

In order to measure the retardation value in the thickness direction of the vertically oriented liquid crystal cured film, a vertically aligned film and a vertically oriented liquid crystal cured film were separately formed on the COP film by the same procedure as described above. An adhesive layer was laminated on the vertically oriented liquid crystal cured film. A film composed of a COP film, an alignment film, and a vertically oriented liquid crystal cured film was bonded to glass via the pressure-sensitive adhesive layer. The COP film was peeled off to obtain a sample for measuring the retardation value. As a result of measuring the phase difference value RthC (550) at a wavelength of 550 nm, RthC (550) = −20 nm. The vertically oriented liquid crystal cured film was a positive C plate satisfying the relationship of nx≈ny <nz.

A corona treatment was applied to a vertically oriented liquid crystal cured film in a film composed of a COP film, a horizontally oriented film, a horizontally oriented liquid crystal cured film, a vertically aligned film, and a vertically oriented liquid crystal cured film. The conditions for corona treatment were the same as above. Both were laminated via an adhesive layer so that the polarizing film in the polarizing plate and the vertically oriented liquid crystal cured film were in contact with each other. At this time, the angle formed by the absorption axis of the polarizing film and the slow axis of the horizontally oriented liquid crystal cured film was 45 °. Finally, the COP film was peeled off to obtain a circular polarizing plate 1 in which a retardation film and a polarizing plate were laminated via an adhesive layer. The circularly polarizing plate 1 had a layer structure of a TAC film, a polarizing film, an adhesive layer, a vertically oriented liquid crystal cured film, a vertically aligned film, a horizontally oriented liquid crystal cured film, and a horizontally oriented film. | RthC (550) | / | RoA (550) | = 0.14.

[Preparation of circular polarizing plate 2]
A circularly polarizing plate 2 was produced in the same manner as the circularly polarizing plate 1 except that the thickness of the vertically oriented liquid crystal cured film was 0.3 μm and RthC (550) = −40 nm. | RthC (550) | / | RoA (550) | = 0.28.

[Preparation of circular polarizing plate 3]
A circular polarizing plate 3 was produced in the same manner as the circular polarizing plate 1 except that the thickness of the vertically oriented liquid crystal cured film was 0.4 μm and RthC (550) = −60 nm. | RthC (550) | / | RoA (550) | = 0.42.

[Preparation of circular polarizing plate 4]
A circularly polarizing plate 4 was produced in the same manner as the circularly polarizing plate 1 except that the thickness of the vertically oriented liquid crystal cured film was 0.5 μm and RthC (550) = −71 nm. | RthC (550) | / | RoA (550) | = 0.50.

[Preparation of circular polarizing plate 5]
A circular polarizing plate 5 was produced in the same manner as in Example 1 except that the film thickness of the vertically oriented liquid crystal cured film was 0.6 μm and RthC (550) = −90 nm. | RthC (550) | / | RoA (550) | = 0.63.

[Preparation of circular polarizing plate 6]
The circularly polarizing plate 6 was produced in the same manner as the circularly polarizing plate 1, except that the vertically oriented liquid crystal cured film was not produced. The circularly polarizing plate 6 had only a horizontally oriented liquid crystal cured film (first retardation film) as a retardation film. | RthC (550) | / | RoA (550) | = 0.

[Example 1]
An adhesive layer was laminated on the exposed surface of the circularly polarizing plate by peeling off the COP film. The circularly polarizing plate 1 and the light reflecting layer 1 were laminated via the pressure-sensitive adhesive layer to obtain a laminated body.

The oblique color difference was measured for the obtained laminate. Specifically, the in-plane angle of the laminated body was changed from the direction of the elevation angle of 50 °, and the reflected hue value was measured by the display evaluation system DMS803. Of the measured reflected hue values, the distance in the a * b * plane between the reflected hue value at the in-plane angle at which the reflected hue value is maximized and the reflected hue value at the angle obtained by adding 90 ° to the in-plane angle is calculated. did.

The hue of the obtained laminate was visually observed when the relationship between the optical axis of the horizontally oriented liquid crystal cured film and the position of the observer was changed. Specifically, the color of the reflected light when visually observed from an elevation angle of about 50 ° at an in-plane angle parallel to the slow axis of the first retardation film, and the phase advance axis of the first retardation film. The color of the reflected light when visually observed from an elevation angle of about 50 ° was evaluated at an in-plane angle parallel to the above. It was judged whether or not the contrast in the diagonal direction was good by the following evaluation criteria.
Good: When viewed from an oblique direction, the reflected light of the outside light is not colored, and a good black display can be realized.
Defective: When viewed from an oblique direction, the reflected light of external light is colored, and it is difficult to achieve a good black display.

As a result, it was found that the oblique color difference of the laminate obtained in Example 1 was 2, the color of the reflected light was uniform when viewed from any direction, and a good black display could be obtained with a wide viewing angle. .. The above results are shown in Table 2.

[Examples 2 to 13, Comparative Examples 1 to 17]
A laminate was produced in the same manner as in Example 1 except that the combination of the circularly polarizing plate and the light reflecting layer was changed as shown in Table 2. With respect to the obtained laminate, the oblique color difference was measured in the same manner as in Example 1. Further, in the obtained laminated body, the color of the reflected light when the relationship between the optical axis of the horizontally oriented liquid crystal cured film and the position of the observer was changed was visually observed in the same manner as in Example 1. The above results are shown in Table 2.

The laminated body of the present invention can suppress coloring of reflected light due to reflection of external light, and can impart good black display ability even when viewed from an oblique direction. The organic EL display device including the laminated body of the present invention can suppress the coloring of the reflected light due to the reflection of external light, and can exhibit a good black display ability even when viewed from an oblique direction.

2 Phase difference film 10 Polarizing film 11, 12 Protective film 13, 14 Adhesive layer 15 Adhesive layer 16 Light reflection layer 20 First retardation film 21 Second retardation film 30 Elevation angle 32 In-plane angle 40 Elevation angle 50 ° 41 Direction in which the reflected hue value is maximized 42 Direction in which the reflected hue value is maximized In-plane angle plus 90 ° 100 Laminated body

Claims (5)

A circularly polarizing plate comprising a polarizing film and phase difference film, and a light reflecting layer, provided in this order of the polarizing film, the retardation film, and the light reflecting layer,
The retardation film includes a first retardation film and a second retardation film.
The first retardation film has the characteristics represented by the formulas (1) to (3).
The second retardation film has the property represented by the formula (4).
The first retardation film and the second retardation film satisfy the relationship of the formula (5).
The light reflecting layer is a laminated body having the characteristics represented by the formula (6).
nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
nx ≒ ny <nz (4)
0.1 <| RthC (550) | / | RoA (550) | ≦ 0.42 (5)
45% <Yref <85% (6)
[In each equation, nx represents the refractive index in the slow axis direction in the film plane.
ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis.
nz represents the refractive index in the thickness direction of the film.
RoA (λ) represents the in-plane retardation value of the first retardation film at the wavelength λ nm.
RthC (λ) represents the retardation value in the thickness direction of the second retardation film at the wavelength λnm.
Yref represents the luminosity factor correction reflectance. ] A circularly polarizing plate comprising a polarizing film and phase difference film, and a light reflecting layer, provided in this order of the polarizing film, the retardation film and the light reflective layer,
The retardation film includes a first retardation film and a second retardation film.
The first retardation film has the characteristics represented by the formulas (1) to (3).
The second retardation film has the property represented by the formula (4).
The first retardation film and the second retardation film satisfy the relationship of the formula (7).
The light reflecting layer is a laminated body having the characteristics represented by the formula (8).
nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
nx ≒ ny <nz (4)
0.55 ≤ | RthC (550) | / | RoA (550) | ≤ 0.8 (7)
90% ≤ Yref <100% (8)
[In each equation, nx represents the refractive index in the slow axis direction in the film plane.
ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis.
nz represents the refractive index in the thickness direction of the film.
RoA (λ) represents the in-plane retardation value of the first retardation film at the wavelength λ nm.
RthC (λ) represents the retardation value in the thickness direction of the second retardation film at the wavelength λnm.
Yref represents the luminosity factor correction reflectance. ] The laminate according to claim 1 or 2 is provided.
When observing from an oblique angle of 50 ° when displayed in black
The oblique hue difference, which is the distance in the a * b * plane between the reflected hue value at the in-plane angle at which the reflected hue value is maximized and the reflected hue value at an angle obtained by adding 90 ° to the in-plane angle, is less than 4. An organic electroluminescence display device. Equipped with a polarizing film and a retardation film,
The retardation film includes a first retardation film and a second retardation film.
The first retardation film has the characteristics represented by the formulas (1) to (3).
The second retardation film has the property represented by the formula (4).
The first retardation film and the second retardation film satisfy the relationship of the equation (5).
A circularly polarizing plate for bonding to a light reflecting layer having the characteristics represented by the formula (6).
nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
nx ≒ ny <nz (4)
0.1 <| RthC (550) | / | RoA (550) | ≦ 0.42 (5)
45% <Yref <85% (6)
[In each equation, nx represents the refractive index in the slow axis direction in the film plane.
ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis.
nz represents the refractive index in the thickness direction of the film.
RoA (λ) represents the in-plane retardation value of the first retardation film at the wavelength λ nm.
RthC (λ) represents the retardation value in the thickness direction of the second retardation film at the wavelength λnm.
Yref represents the luminosity factor correction reflectance. ] Equipped with a polarizing film and a retardation film,
The retardation film includes a first retardation film and a second retardation film.
The first retardation film has the characteristics represented by the formulas (1) to (3).
The second retardation film has the property represented by the formula (4).
The first retardation film and the second retardation film satisfy the relationship of the formula (7).
A circularly polarizing plate for bonding to a light reflecting layer having the characteristics represented by the formula (8).
nx> ny ≒ nz (1)
RoA (450) / RoA (550) ≤ 0.93 (2)
135nm <RoA (550) <145nm (3)
nx ≒ ny <nz (4)
0.55 ≤ | RthC (550) | / | RoA (550) | ≤ 0.8 (7)
90% ≤ Yref <100% (8)
[In each equation, nx represents the refractive index in the slow axis direction in the film plane.
ny represents the refractive index in the film plane in the direction orthogonal to the slow phase axis.
nz represents the refractive index in the thickness direction of the film.
RoA (λ) represents the in-plane retardation value of the first retardation film at the wavelength λ nm.
RthC (λ) represents the retardation value in the thickness direction of the second retardation film at the wavelength λnm.
Yref represents the luminosity factor correction reflectance. ]

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