TWI753266B - Laminate, organic electroluminescence display device, and use of circularly polarizing plate - Google Patents

Abstract

An object of the present invention is to provide a laminate including a circularly polarizing plate that suppresses coloring of reflected light due to external light reflection and can impart a good black display ability even when viewed from an oblique direction.

The laminate has a polarizing film, a retardation film and a light reflection layer in this order, wherein the retardation film has a first retardation film and a second retardation film, the first retardation film has characteristics represented by formulas (1) to (3), the second retardation film has the characteristics represented by the formula (4), the retardation film has the characteristics represented by the formula (5), and the light reflecting layer has a characteristic 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)

Description

Application of laminated body, organic electroluminescence display device and circularly polarizing plate

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 spread. In the organic EL display device, since the electrodes assembled inside will become a light reflection layer that reflects external light, a polarizing film and a retardation film (λ/4 plate, retardation value) are usually mounted. about 140nm) circular polarizer. By arranging the circularly polarizing plate on the front side of the organic EL display element, reflection of external light caused by internal electrodes and the like can be prevented, and the visibility of the screen can be improved. The ability of a display device to prevent reflection of external light is directly related to the ability to render black as it is. The higher this performance, the higher the contrast of the display device becomes.

The circular polarizing plate can be obtained by combining the polarizing film and the A plate. The phase difference value of the A plate is different in appearance when viewed from an oblique direction and when viewed from a frontal direction. Therefore, the color tone of the reflected light will change due to the difference in the viewing direction of the screen, and there are differences in the display device. Contrast reduction problem.

In order to compensate for such a change in the phase difference value depending on the direction in which the screen is viewed, it has been proposed to further combine a C-plate (Patent Document 1). The C-plate system compensates for the phase difference when viewed from an oblique direction, and contributes to the improvement of contrast. The magnitude of the compensation effect is determined by the relationship between the in-plane retardation value RoA of the A plate and the retardation value RthC in the thickness direction of the C plate. In either case of under-compensation or over-compensation, color shift will be observed in reflected light, which may cause a decrease in contrast when viewed from an oblique direction. Conventionally, from the standpoint of theoretical calculation, the retardation value RthC in the thickness direction of the C plate required for ideal compensation can be considered to be 1/2 of the in-plane retardation value of the A plate. However, a display device equipped with a circularly polarizing plate having such a designed retardation film cannot necessarily achieve a contrast that is not dependent on the viewing screen direction.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-40603

An object of the present invention is to provide a laminate, and an organic EL display device including the laminate; the laminate system includes a laminate of a circular polarizer and a light reflection layer, and the laminate system can suppress reflection by the light reflection layer The color shift of the reflected light can give a good black display ability even when viewed from an oblique direction.

The present invention provides the following laminates.

A laminated body is provided with a polarizing film, a retardation film and a light reflection layer in sequence;

The aforementioned retardation film has a first retardation film and a second retardation film,

The above-mentioned first retardation film has the characteristics represented by the formulas (1) to (3),

The above-mentioned second retardation film has the characteristic represented by the formula (4),

The first retardation film and the second retardation film satisfy the relationship of the formula (5),

The said light reflection layer has the characteristic represented by 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 formula, nx represents the refractive index in the slow axis direction in the film plane,

ny represents the refractive index in the film plane and in the direction orthogonal to the slow 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 wavelength λnm,

RthC(λ) represents the retardation value of the second retardation film in the thickness direction at a wavelength of λnm,

Yref represents the luminous factor (also known as visual sensitivity) corrected reflectance].

[2] A laminate comprising a polarizing film, a retardation film and a light reflection layer in this order;

The aforementioned retardation film has a first retardation film and a second retardation film,

The above-mentioned first retardation film has the characteristics represented by the formulas (1) to (3),

The above-mentioned second retardation film has the characteristic represented by the formula (4),

The first retardation film and the second retardation film satisfy the relationship of the formula (7),

The said light reflection layer has the characteristic represented by 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 formula, nx represents the refractive index in the slow axis direction in the film plane,

ny represents the refractive index in the film plane and in the direction orthogonal to the slow 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 wavelength λnm,

RthC(λ) represents the retardation value of the second retardation film in the thickness direction at a wavelength of λnm,

Yref represents the luminous factor corrected reflectance. ]

The present invention provides the following organic electroluminescence display device.

An organic electroluminescence display device comprising the laminate according to [1] or [2],

In black display, when viewed from an oblique angle with an elevation angle of 50°,

The oblique angle difference between the reflection hue value at the in-plane angle at which the reflection hue value becomes the largest and the reflection hue value at the angle obtained by adding 90° to the in-plane angle in the a*b* plane is less than 4.

[4] A circularly polarizing plate, which is used to adhere to a light reflection layer having the characteristics represented by the formula (6),

The circularly polarizing plate is provided with a polarizing film and a retardation film,

The aforementioned retardation film has a first retardation film and a second retardation film,

The above-mentioned first retardation film has the characteristics represented by the formulas (1) to (3),

The above-mentioned second retardation film has the characteristic represented by the formula (4),

The first retardation film and the second retardation film satisfy the relationship of formula (5);

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 formula, nx represents the refractive index in the slow axis direction in the film plane,

ny represents the refractive index in the film plane and in the direction orthogonal to the slow 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 wavelength λnm,

RthC(λ) represents the retardation value of the second retardation film in the thickness direction at a wavelength of λnm,

Yref denotes luminous factor corrected reflectance].

The present invention provides the following circular polarizing plate.

A circular polarizing plate, which is used for sticking to a light reflective layer having the characteristics represented by formula (8),

The circularly polarizing plate is provided with a polarizing film and a retardation film,

The aforementioned retardation film has a first retardation film and a second retardation film,

The above-mentioned first retardation film has the characteristics represented by the formulas (1) to (3),

The above-mentioned second retardation film has the characteristic represented by the formula (4),

The said 1st retardation film and the said 2nd retardation film satisfy the relationship of Formula (7).

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 formula, nx represents the refractive index in the slow axis direction in the film plane,

ny represents the refractive index in the film plane and in the direction orthogonal to the slow 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 wavelength λnm,

RthC(λ) represents the retardation value of the second retardation film in the thickness direction at a wavelength of λnm,

Yref indicates luminous factor corrected reflectance]

In the laminated body of the present invention, even when the light reflection layer has the characteristics expressed by the formula (6), the first retardation film and the second retardation film satisfy the relationship expressed by the formula (5). When the light reflective layer has the characteristics represented by the formula (8), the first retardation film and the second retardation film also satisfy the relationship represented by the formula (7), so it is possible to suppress the external The color shift of the reflected light caused by the light reflection can give a good black display ability even when viewed from an oblique direction. The organic EL display device provided with the laminate of the present invention can suppress the color shift of the reflected light caused by the reflection of external light, and can exhibit good black display ability even when viewed from an oblique direction.

2: retardation film

10: Polarizing film

11, 12: Protective film

13, 14: Adhesive layer

15: Next layer

16: Light reflection layer

20: 1st retardation film

21: Second retardation film

30‧‧‧Elevation

32‧‧‧In-plane angle

40, 41, 42‧‧‧ directions

100‧‧‧Laminate

FIG. 1 is an example of a schematic cross-sectional view showing the layer structure of the laminate.

FIG. 2 is a schematic diagram for explaining the measurement of the oblique angle difference.

<Laminated body>

The laminate system of the present invention includes a polarizing film, a retardation film, and a light reflection layer in this order. The polarizing film, retardation film, light reflection layer, and other members may be laminated to each other via an adhesive layer. As the next layer, for example, an adhesive layer or an adhesive layer which will be described later is exemplified.

An example of the layer structure of the laminate of the present invention will be described below with reference to FIG. 1 . In addition, in FIG. 1, the adhesive layer for bonding the polarizing film 10 and the protective films 11 and 12, respectively, is not indicated. The laminated body 100 shown in FIG. 1 is composed of layers including a polarizing plate, a retardation film 2 and a light reflecting layer 16 laminated in sequence; And a second protective film 12 is layered on another area of the polarizing film 10 .

The polarizing plate and the retardation film 2 are laminated via the adhesive layer 13 , and the retardation film 2 and the light reflection layer 16 are laminated via the adhesive layer 14 . The retardation film 2 is formed by laminating the first retardation film 20 and the second retardation film 21 via the adhesive layer 15 . Moreover, in addition to the 1st retardation film and the 2nd retardation film, the retardation film may have, for example, an alignment film for orienting a polymerizable liquid crystal compound, a base film, or another retardation layer. The light reflection layer 16 may be, for example, an electrode included in an organic EL display element. In this case, a transparent or semi-transparent electrode, a hole injection layer, a hole transport layer, an organic light-emitting layer, a hole prevention layer, an electron transport layer, At least one layer of the group consisting of electron injection layers.

The order of lamination of the first retardation film and the second retardation film is arbitrary. That is, the laminated body of the present invention may include a polarizing film, a first retardation film, a second retardation film, and a light reflection layer in this order, or may include a polarizing film, a second retardation film, and a first retardation film in this order. film and light reflective layer.

The layered body may have layers other than those shown in FIG. 1 . The layer which the laminated body may have further includes a front panel, a light-shielding pattern, a touch sensor, and the like. The front panel may be arranged on the opposite side of the polarizing plate to the side on which the retardation film is laminated. The light-shielding pattern may be formed on the polarizer-side surface of the front panel. The light-shielding pattern is formed on the frame edge (non-display area) of the image display device, and is provided so that the wiring of the image display device cannot be seen by the user. The touch sensor can be arranged between the front panel and the laminated body, or between the retardation film and the light reflection layer of the laminated body, or the like.

The shape of the layered product of the present invention is not particularly limited. When the layered body 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 preferably 5 cm or more and 25 cm or less, particularly preferably 6 cm or more and 20 cm or less. .

A substantially rectangular shape means that the layered system has a shape that is cut out so that at least one of the four corners (corners) of the main surface becomes an obtuse angle, or a shape with rounded corners, which can be perpendicular to the main surface. A part of the end face has a concave portion (groove) concave in the in-plane direction, or a part of the main face can have an opening portion that is drilled into a shape of a circle, an ellipse, a polygon, and a combination of these. By.

In the organic EL display device provided with the laminated body of the present invention, it is preferable that the oblique angle difference is less than 4, and it is more preferable that it is less than 3. The lower limit value of the oblique angle difference is not particularly limited, but is ideally 0. By making the oblique angle difference to this value, the color tone of the reflected light of the organic EL display device can be made more uniform.

In this specification, the oblique angular difference refers to the reflection hue value at the in-plane angle at which the reflection hue value becomes the largest when viewed from a direction with an elevation angle of 50° when the organic EL display device is in a black display state, and the reflection hue value at the The distance in the a*b* plane of the reflected hue value at the angle after adding 90° to the in-plane angle. The in-plane angle at which the reflection hue value becomes the largest means the angle at which the reflection hue value becomes the largest when the reflection hue value is measured by changing the in-plane angle from 0° to 360° with an elevation angle of 50°.

Specifically, the diagonal angle difference will be described with reference to FIG. 2 . Fig. 2(a) shows the laminate 100 viewed from the side. The reflection hue value for calculating the oblique angular difference is the value observed from the direction 40 where the elevation angle 30 becomes 50°. Fig. 2(b) is a view of the laminate 100 viewed from above (from the opposite side to the retardation film side based on the polarizer). The oblique angular difference is measured from the reflection hue value when viewed from the direction 41 where the reflection hue value becomes the largest, and when viewed from the direction 42 which is an angle obtained by adding 90° (in-plane angle 32) to the in-plane angle in this direction 41 The reflection hue value of , and the distance in the a*b* plane of the two is calculated from the following formula.

Oblique angle difference = (△a* ² +△b* ² ) ^1/2

Regarding the reflection hue value when viewed from the direction 41 where the reflection hue value becomes the largest, 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, more preferably -1.5 or more and 1.5 or less.

Regarding the reflection hue value when viewed from the direction 42 which is an angle obtained by adding 90° (angle 32) to the in-plane angle of the direction 41, a* is preferably -3 or more and 3 or less, more preferably -1.5 or more and 1.5 or less. b* is preferably -3 or more and 3 or less, more preferably -1.5 or more and 1.5 or less.

<Polarizer>

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

(1) Polarizing film

The polarizing film of the polarizing plate can be an absorption-type polarizing film with the following properties: absorbing linearly polarized light with a vibration plane parallel to the absorption axis of the polarizing film, and making it perpendicular to the absorption axis (and the transmission axis). The nature of the linearly polarized light penetration of the vibration plane parallel to it. As the polarizing film included in the first layer, a polarizing film in which a dichroic dye is adsorbed and oriented to a uniaxially stretched polyvinyl alcohol-based resin film can be suitably used. The polarizing film can be produced, for example, by a method including the following steps: a step of uniaxially extending a polyvinyl alcohol-based resin film; a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye ; The step of treating the polyvinyl alcohol-based resin film with the dichroic dye adsorbed with the cross-linking liquid such as boric acid aqueous solution; and the step of washing with water after the treatment with the cross-linking liquid.

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

In this specification, "(meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid. 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 can be modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The average degree of polymerization of the polyvinyl alcohol-based 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 in accordance with JIS K 6726.

A film formed by forming such a polyvinyl alcohol-based resin into a film can be used as an original film of a polarizing film. The method of forming a film of the polyvinyl alcohol-based resin is not particularly limited, and a generally known method can be employed. The thickness of the polyvinyl alcohol-based original film is not particularly limited, but in order to make the thickness of the polarizing film 15 μm or less, it is preferable to use one of 5 to 35 μm. More preferably, it is 20 μm or less.

The uniaxial stretching of the polyvinyl alcohol-based resin film may be performed before the dyeing of the dichroic dye, simultaneously with the dyeing, or after the dyeing. In the case of performing uniaxial extension after dyeing, the uniaxial extension may be performed before or during the cross-linking treatment. Furthermore, uniaxial stretching may be performed in these plural stages.

In the case of uniaxial stretching, uniaxial stretching may be performed between rolls having different rotational speeds, or uniaxial stretching may be performed using hot rolls. In addition, the uniaxial stretching may be dry stretching in which the stretching is performed in the atmosphere, or wet stretching in which the polyvinyl alcohol-based resin film is swelled using a solvent or water. The elongation 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 can be employed. Dichroic pigments can be iodine or dichroic organic dyes. In addition, the polyvinyl alcohol-based resin film is preferably subjected to a dipping treatment of dipping in water before the dyeing treatment.

For the crosslinking treatment after dyeing with a dichroic dye, a method of immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid can generally be employed. In the case of using iodine 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, a dichroic dye is used in the cured film in which the liquid crystal compound is polymerized as described in JP-A No. 2016-170368. Dichroic dyes can be used for those with absorption in the wavelength range of 380 to 800 nm, and organic dyes are preferably used. As a dichroic dye, an azo compound is mentioned, for example. The liquid crystal compound is a liquid crystal compound that can be polymerized in an oriented state, and may have a polymerizable group in the molecule. Moreover, as described in WO2011/024891, a polarizing film can be formed from a dichroic dye having liquid crystallinity.

The luminous factor correction polarization degree of the polarizing film is preferably 90% or more, more preferably 95% or more. The upper limit value is not particularly limited, and may be 99.9999% or less. In addition, the transmittance of the light-emitting factor correction monomer of the polarizing film is preferably 35% or more, more preferably 40% or more. The upper limit value is not particularly limited, and may be 49.9% or less. By providing a polarizing film with such a performance in a laminated body, the reflected light can be less likely to be leaked, and the color shift can be made inconspicuous.

(2) Protective film

The protective film laminated on one side or both sides of the polarizing film may be a thermoplastic resin having light transmittance (preferably optical transparency). Examples of the protective film include films composed of polyolefin-based resins such as linear polyolefin-based resins (polypropylene-based resins, etc.) and cyclic polyolefin-based resins (norbornene-based resins, etc.) ; Cellulose resins such as cellulose triacetate and cellulose diacetate; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate resins; (meth)acrylic resins such as methyl methacrylate resins; polystyrene resins; polyvinyl chloride resins; acrylonitrile-butadiene-styrene resins; acrylonitrile-styrene resins; poly Vinyl acetate series resin; polyvinylidene chloride series resin; polyamide series resin; polyacetal series resin; modified polyphenylene ether series resin; arylate resin; polyamide imide resin; polyimide resin, etc.

As far as chain polyolefin resins are concerned, except for polyethylene resins (polyethylene resins of ethylene homopolymers or copolymers with ethylene as the main body), polypropylene resins (polypropylene resins of propylene homopolymers or other In addition to homopolymers of chain olefins such as propylene-based copolymers), copolymers composed of two or more kinds of chain olefins can be exemplified.

Cyclic polyolefin-based resin is a general term for resins polymerized with cyclic olefins as polymerized units, for example, Japanese Patent Laid-Open No. 1-240517, Japanese Patent Laid-Open No. 3-14882, and Japanese Patent Laid-Open No. 3-122137 No. Bulletin, etc. described in the resin. Specific examples of cyclic polyolefin-based resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, cyclic olefins, and chain olefins such as ethylene and propylene. Copolymers (representatives are random copolymers), graft polymers modified with unsaturated carboxylic acids or derivatives thereof, and hydrides of these. Among them, norbornene-based resins using norbornene-based monomers such as norbornene-based or polycyclic norbornene-based monomers as cyclic olefins can be suitably used.

The polyester resin is a resin having an ester bond other than the following cellulose ester resin, and is generally composed of a polycondensate of a polyvalent carboxylic acid or a derivative of a polyvalent carboxylic acid and a polyhydric alcohol. As a polyvalent carboxylic acid or a derivative of a polyvalent carboxylic acid, a divalent dicarboxylic acid or a derivative of a dicarboxylic acid can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and naphthalene. Dimethyl dicarboxylate, etc. As a polyhydric alcohol, a divalent diol can be used, for example, ethylene glycol, propylene glycol, butanediol, neopentyl glycol, cyclohexanedimethanol, etc. are mentioned. A typical example of the polyester-based resin includes polyethylene terephthalate which is a polycondensate of terephthalic acid and ethylene glycol.

(Meth)acrylic resin is a resin whose main constituent monomer is a compound having a (meth)acryloyl group. Specific examples of (meth)acrylic resins include, for example, poly(meth)acrylates such as polymethyl methacrylate; methyl methacrylate-(meth)acrylic acid copolymers; methyl methacrylate- (meth)acrylate copolymer; methyl methacrylate-acrylate-(meth)acrylic acid copolymer; methyl methacrylate-styrene copolymer (MS resin, etc.); Copolymers of cyclic hydrocarbon-based compounds (eg methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl methacrylate copolymer, etc.). It is preferable to use a polymer whose main component is poly(meth)acrylate C _1-6 alkyl ester such as poly(meth)acrylate, and it is more preferable to use methyl methacrylate as the main component (50 to 100% by weight, preferably 70 to 100% by weight) of methyl methacrylate resin.

Cellulose ester resins are esters of cellulose and fatty acids. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. In addition, these copolymers, or a part of the hydroxyl group modified with other substituents, etc. can also be mentioned. Among these, cellulose triacetate (cellulose triacetate) is particularly preferred.

Polycarbonate resins are engineering plastics composed of polymers in which monomer units are bonded through carbonate groups.

The retardation value of the protective film can be appropriately controlled to a preferred value. In order to improve the visibility of the screen when the user wears polarized sunglasses, etc., the in-plane retardation value at a wavelength of 550 nm is preferably set to 70 to 140 nm.

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

The protective film attached to both sides of the polarizing film may be composed of the same kind of thermoplastic resin, or may be composed of different kinds of thermoplastic resin. In addition, the thickness may be the same or different. Furthermore, it may have the same phase difference characteristics, or may have different phase difference characteristics.

As described above, at least any one of the protective films may be provided with, for example, a hard coat layer, an antiglare layer, a light diffusion layer, an antireflection layer, a low refraction layer on the outer surface of the protective film (the surface opposite to the polarizing film) Surface treatment layer (coating layer) such as rate layer, antistatic layer and antifouling layer. The thickness of the protective film includes the thickness of the surface treatment layer.

The protective film can be bonded to the polarizing film via, for example, an adhesive layer or an adhesive layer. 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, and a water-based adhesive or an active energy ray-curable adhesive is preferable. The latter can be used as the adhesive layer.

The water-based adhesive includes an adhesive composed of a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion-type adhesive, and the like. Among them, a water-based adhesive composed of a polyvinyl alcohol-based resin aqueous solution is particularly suitable. As the polyvinyl alcohol-based resin, in addition to a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, vinyl acetate and vinyl acetate copolymers can also be used. A polyvinyl alcohol-based copolymer obtained by saponifying a copolymer of other monomers, or a modified polyvinyl alcohol-based copolymer in which the hydroxyl groups of these are partially modified. The water-based adhesive may contain crosslinking agents such as aldehyde compounds (glyoxal, etc.), epoxy compounds, melamine-based compounds, methylol compounds, isocyanate compounds, amine compounds, and polyvalent metal salts.

In the case of using a water-based adhesive, it is preferable to perform a drying step for removing water contained in the water-based adhesive after bonding the polarizing film and the protective film. After the drying step, an aging step such as aging at a temperature of about 20 to 45° C. may be provided.

The above-mentioned 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 rays, and X-rays, preferably ultraviolet curable. Then agent.

The above-mentioned curable compound may be a cationically polymerizable curable compound or a radically polymerizable curable compound. Examples of cationically polymerizable curable compounds include epoxy-based compounds (compounds having one or more epoxy groups in the molecule), oxetane-based compounds (having one or more epoxy groups in the molecule). 2 or more oxetane rings), or a combination of these. Examples of radically polymerizable curable compounds include (meth)acrylic compounds (compounds having one or more (meth)acryloyloxy groups in the molecule), radically polymerizable compounds Other vinyl compounds with double bonds, or a combination of these. 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 starting the curing reaction of the above-mentioned curable compound.

When bonding a polarizing film and a protective film, in order to improve adhesiveness, surface activation treatment can be given to the bonding surface of at least any one of these. Examples of surface activation treatments include corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, free active ray treatment (ultraviolet treatment, electron beam treatment, etc.) Dry treatment; wet treatment such as ultrasonic treatment, saponification treatment, and anchor coat treatment using solvents such as water or acetone. These surface activation treatments may be performed alone or in combination of two or more.

In the case where protective films are attached to both sides of the polarizing film, the adhesives used for laminating these protective films may be the same type of adhesive, or may be different types of adhesives.

<retardation film>

The retardation film includes a first retardation film and a second retardation film. In addition, the retardation film may contain the later-mentioned base material, an alignment film, and other retardation layers.

The first retardation film has characteristics represented by formulas (1) to (3). The first retardation film may be a positive A plate or a λ/4 plate. In addition, the first retardation film exhibits negative wavelength dispersion properties. By providing such a 1st retardation film, the color shift of reflected light can be suppressed. The slow axis of the first retardation film can be arranged so as to be approximately 45° with respect to the absorption axis of the polarizing film. Roughly 45° means 45±5°.

nx>ny≒nz (1)

RoA(450)/RoA(550)≦0.93 (2)

135nm<RoA(550)<145nm (3)

In equations (1) to (3), nx represents the refractive index in the direction of the slow axis in the film plane, ny represents the refractive index in the direction in the film plane and perpendicular to the slow axis, and nz represents the thickness direction of the film. refractive index. RoA(λ) represents the in-plane retardation value of the first retardation film at a wavelength of λnm.

ny≒nz not only includes the case where ny and nz are completely equal, but also includes 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) and the thickness d at the wavelength λnm according to the following formula.

RoA(λ)=[nx(λ)-ny(λ)]×d

RoA(450)/RoA(550) represents the wavelength dispersion of the first retardation film, and is preferably 0.92 or less.

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

The second retardation film has characteristics represented by the formula (4). The second retardation film may be a positive-C plate. By having such a second retardation film, the color shift of the reflected light can be suppressed.

nx≒ny<nz (4)

In 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 and in the direction orthogonal to the slow axis, and nz represents the refractive index in the thickness direction of the film.

In addition to the case where nx and ny are completely equal, nx≒ny also includes 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 reflection layer to be described later, specifically, the retardation value in the thickness direction of the second retardation film at a wavelength of 550 nm is preferably -150 nm or more and 0 nm or less, more preferably -90 nm or more and -20 nm the following.

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

The other retardation layers may be A-plates, but typically C-plates. Other retardation layers may have the characteristics represented by the formula (9). That is, the other retardation layer may be a negative C plate.

nx≒ny>nz (9)

In addition to the case where nx and ny are completely equal, nx≒ny also includes 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 formula (7) by correcting the reflectance according to the luminous factor of the light reflection layer.

0.1<|RthC(550)|/|RoA(550)|<0.5 (5)

0.5<|RthC(550)|/|RoA(550)|<1.0 (7)

In equations (5) and (7), RoA(λ) represents the in-plane retardation value of the first retardation film at a wavelength of λnm, and RthC(λ) represents the thickness direction of the second retardation film at a wavelength of λnm phase difference value.

RthC(λ) can be calculated from the refractive index n(λ) and the thickness d at the wavelength λnm according to the following formula.

RthC(λ)={[nx(λ)+ny(λ)]/2-nz}×d

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

The above equations (5) and (7) are based on the results after careful research by the inventor. The results are obtained: the most suitable compensation value in the actual display device will be due to the reflection of the light reflection layer. characteristics differ from the conventional ideal compensation value.

When the light reflection layer satisfies the properties 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 is smaller than 0.5, which was conventionally considered to achieve ideal compensation. By satisfying the relationship of the formula (5), even when the light reflection layer has the characteristics of the formula (6), the laminate of the present invention can achieve a good black display when viewed from an oblique direction. |RthC(550)|/|RoA(550)| is preferably more than 0.1 and less than 0.5, more preferably 0.2 or more and 0.4 or less. By making the retardation film satisfy the above relationship, the color shift of the reflected light when viewed from an oblique direction can be suppressed.

On the other hand, when the light reflection 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 is larger than 0.5, which was conventionally considered to achieve ideal compensation. By satisfying the relationship of the formula (7), even when the light reflection layer has the characteristics of the formula (8), the laminate of the present invention can achieve a good black display when viewed from an oblique direction. |RthC(550)|/RoA(550)| is preferably more than 0.5 and less than 1.0, particularly preferably 0.55 or more and 0.8 or less. By making the retardation film satisfy the above relationship, the color shift of the reflected light when viewed from an oblique direction can be suppressed.

The 1st retardation film and the 2nd retardation film which form a retardation film can be formed from the composition containing the said thermoplastic resin film or a polymerizable liquid crystal compound. The first retardation film and the second retardation film are preferably formed of a composition containing a polymerizable liquid crystal compound. The layer formed from the composition containing the polymerizable liquid crystal compound includes a layer hardened by the polymerizable liquid crystal compound.

The relationship between the equations (1) to (3) satisfied by the first retardation film, the relationship of the equation (4) satisfied by the second retardation film, and the equation (5) or the equation (7) satisfied by the retardation film relationship, for example, by adjusting the type and mixing ratio of the thermoplastic resin or polymerizable liquid crystal compound forming the first retardation film and the second retardation film, or by adjusting the thickness of the first retardation film and the second retardation film to control.

The layer system hardened by the polymerizable liquid crystal compound can be formed on, for example, an alignment film provided on a base material. The aforementioned substrate has the function of supporting the orientation film, and can be a long-shaped substrate. This base material functions as a releasable support, and can support a retardation film for transfer. Furthermore, it is preferable that the surface has a peelable adhesive force. As said base material, the resin film exemplified as the material of the said protective film is mentioned.

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 can be imparted. On the other hand, when the thickness is 200 μm or less, when the base material is cut into a single-piece base material, an increase in machining debris and abrasion of the cutting blade can be suppressed.

Also, the substrate may be subjected to various anti-blocking treatments. The anti-sticking treatment includes, for example, an easy-bonding treatment, a treatment for mixing a filler and the like, an embossing process (knurling treatment), and the like. By applying such anti-sticking treatment to the base material, it is possible to effectively prevent the base materials from adhering to each other (ie, sticking) when the base material is wound, so that the optical film can be manufactured with high productivity.

The layer hardened by the polymerizable liquid crystal compound can be formed on the substrate through an alignment film. That is, a base material and an alignment film are laminated in this order, and the layer hardened by the polymerizable liquid crystal compound is laminated on the above-mentioned alignment film.

In addition, the alignment film is not limited to the vertical alignment film, and may be an alignment film in which the molecular axis of the polymerizable liquid crystal compound is oriented horizontally, or an alignment film in which the molecular axis of the polymerizable liquid crystal compound is oriented obliquely. In the case of producing the first retardation film, a horizontal alignment film can be used; in the case of producing the second retardation film, a vertical alignment film can be used. The alignment film preferably has solvent resistance that is not dissolved by application of a composition containing a polymerizable liquid crystal compound, etc. described later, and heat resistance under heat treatment for removing the solvent or alignment of the liquid crystal compound. . The alignment film includes an alignment film containing an alignment polymer, a light alignment film, and a groove alignment film in which a concavo-convex pattern or a plurality of grooves are formed on the surface and oriented. 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 still more 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 generally known resin that can be used as a material for the alignment film, and a conventionally known monofunctional or polyfunctional (methyl) resin can be used in the presence of a polymerization initiator. ) Hardened products of acrylate monomers, etc. Specifically, the (meth)acrylate-based monomers include, for example, 2-ethylhexyl acrylate, cyclohexyl acrylate, diethylene glycol mono 2-ethylhexyl ether acrylate, and diethylene glycol mono Phenyl Ether Acrylate, Tetraethylene Glycol Monophenyl Ether Acrylate, Trimethylolpropyl Triacrylate, Lauryl Acrylate, Lauryl Methacrylate, Isobornyl Acrylate, Isobornyl Methacrylate, 2-Benzene Acrylate Oxyethyl ester, tetrahydrofurfuryl acrylate, 2-hydroxypropyl acrylate, benzyl acrylate, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate ester, methacrylic acid, urethane acrylate, etc. In addition, the resin may be one type of these examples, or may be a mixture of two or more types.

Although the type of the polymerizable liquid crystal compound used in this embodiment is not particularly limited, it can be classified into rod-like (rod-like liquid crystal compound), discotic (disc-like liquid crystal compound, discotic liquid crystal compound) according to the shape of the compound. compound). Furthermore, these compounds have low molecular type and high molecular type, respectively. In addition, the term "polymer" generally means one having a degree of polymerization of 100 or more (Polymer Physics/Phase Transfer Kinetics, by Masao Doi, p. 2, Iwanami Shoten, 1992).

In this embodiment, any liquid crystal compound can be used. Furthermore, two or more types of rod-like liquid crystal compounds, two or more types of discotic liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a discotic liquid crystal compound may be used.

Further, as the rod-like liquid crystal compound, for example, those described in the first item of the scope of application of JP-A No. 11-513019, or those described in paragraphs [0026] to [0098] of JP-A No. 2005-289980 can be suitably used. recorder. As the discotic liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP 2007-108732 A, or those described in paragraphs [0013] to [0108] in JP 2010-244038 A can be suitably used. recorder.

The polymerizable liquid crystal compound may be used in combination of two or more. In this case, at least one species has two or more polymerizable groups in the molecule. That is, it is preferable that the layer hardened|cured by the said polymerizable liquid crystal compound is a layer formed by polymerizing and fixing the liquid crystal compound which has a polymerizable group. In this case, it is no longer necessary to exhibit liquid crystallinity after becoming a layer.

The polymerizable liquid crystal compound has a polymerizable group capable of a polymerization reaction. The polymerizable group is preferably a functional group that can undergo an addition polymerization reaction, such as a polymerizable ethylenically unsaturated group or a cyclopolymerizable group. More specifically, as a polymerizable group, a (meth)acryloyl group, a vinyl group, a styryl group, an allyl group, etc. are mentioned, for example. Among them, the (meth)acryloyl group is particularly preferred. In addition, a (meth)acryloyl group is a concept including both a methacryloyl group and an acryl group.

The layer to be cured by the polymerizable liquid crystal compound can be formed by, for example, applying a composition containing the polymerizable liquid crystal compound to, for example, an alignment film, as described later. Components other than the above-mentioned polymerizable liquid crystal compound may be contained in the above-mentioned composition. For example, in the composition, it is preferable to contain a polymerization initiator. The polymerization initiator to be used can be selected according to the form of the polymerization reaction, for example, a thermal polymerization initiator or a photopolymerization initiator. Examples of photopolymerization initiators include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynucleoquinone compounds, triarylimidazole dimers, and p-amines A combination of phenyl ketones, etc. The amount of the polymerization initiator to be used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, relative to the total solid content in the aforementioned coating liquid.

In addition, from the viewpoint of the uniformity of the coating film and the strength of the film, a polymerizable monomer may be contained in the aforementioned composition. The polymerizable monomer includes radically polymerizable or cationically polymerizable compounds. Among them, polyfunctional radically polymerizable monomers are particularly preferred.

Moreover, it is preferable that a polymerizable monomer can be copolymerized with the said polymerizable liquid crystal compound. Specific polymerizable monomers include, for example, those described in paragraphs [0018] to [0020] of JP-A No. 2002-296423. The amount of the polymerizable monomer to be used is preferably 1 to 50 mass %, more preferably 2 to 30 mass % with respect to the total mass of the polymerizable liquid crystal compound.

In addition, from the viewpoint of the uniformity of the coating film and the strength of the film, a surfactant may be contained in the aforementioned composition. As the surfactant, conventionally known compounds can be exemplified. Among them, fluorine-based compounds are particularly preferred. Specific examples of surfactants include compounds described in paragraphs [0028] to [0056] of Japanese Patent Application Laid-Open No. 2001-330725, and paragraphs [0069] to [0126] of Japanese Patent Application No. 2003-295212 ] The compound described.

Moreover, a solvent may be contained in the said composition, and an organic solvent can be used suitably. Examples of the organic solvent include amides (for example, N,N-dimethylformamide), sulfene (for example, dimethylsulfoxide), heterocyclic compounds (for example, pyridine), and hydrocarbons (for example, benzene and hexane) , halogenated alkanes (such as chloroform, dichloromethane), esters (such as methyl acetate, ethyl acetate, butyl acetate), ketones (such as acetone, methyl ethyl ketone), ethers (such as tetrahydrofuran, 1,2-dimethoxyethane). Among them, halogenated alkanes and ketones are particularly preferred. Moreover, 2 or more types of organic solvents can be used together.

In addition, various alignment agents may be contained in the aforementioned composition, such as vertical alignment accelerators such as so-called polarizing film interface side vertical alignment agents, air interface side vertical alignment agents, and polarizing film interface side horizontal alignment agents, air interface side horizontal alignment agents agent and other horizontal orientation accelerators. Furthermore, in addition to the above-mentioned components, an adhesion improver, a plasticizer, a polymer, etc. may be contained in the said composition.

In this embodiment, the thickness of the 1st retardation film and the 2nd retardation film can be 0.1 micrometer or more and 5 micrometers or less. When the thicknesses of the first retardation film and the second retardation film are within the aforementioned range, sufficient durability can be obtained, and it can contribute to the reduction of the thickness of the laminate. As a matter of course, the thickness of the first retardation film and the second retardation film can obtain a desired in-plane phase such as a layer with a retardation of λ/4, a layer with a retardation of λ/2, or a positive C plate. The difference value and the retardation value in the thickness direction are adjusted.

In the case where the retardation film is the first retardation film and the second retardation film as the layer which is cured by the polymerizable liquid crystal compound containing two layers, it can be cured by producing the polymerizable liquid crystal compound on the alignment film, respectively. A retardation film is produced by laminating the two layers through an adhesive layer or an adhesive layer. After laminating the two, the base material and the orientation 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 reflection layer is a layer that reflects light incident on the laminate, and typically includes electrodes included in an 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. By injecting electrons from one electrode and injecting holes from the other electrode to the organic light-emitting material layer, electrons and holes are combined in the organic light-emitting material layer and self-luminescence is performed. Compared with liquid crystal display elements that must be equipped with a backlight, it has the advantages of better visibility, further thinning, and low-voltage DC driving.

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

The light reflection layer satisfies the following formula (6) or formula (8) according to the characteristics of the retardation film.

45%<Yref<85% (6)

85%≦Yref<100% (8) In equations (6) and (8), Yref represents the luminous factor corrected reflectance.

Yref is the reflectance measured by the SCI (Specular Component Include) method including specularly reflected light, and is the reflection after the luminous factor correction is performed by the color-matching function (color-matching function) y(λ) (JIS Z 8701). Rate. Yref can be measured by a spectrophotometer.

As described above, when the retardation film satisfies the relationship of the formula (5), the light reflection layer satisfies the characteristics represented by the formula (6); when the retardation film satisfies the relationship of the formula (7), the light The reflection layer satisfies the characteristics represented by the formula (8). By the combination of such a retardation film and a light reflection layer, the color shift of the reflected light when viewed from an oblique direction can be suppressed. In formula (6), Yref is preferably 45% or more and 80% or less; in formula (8), Yref is preferably 90% or more and 99.9% or less, more preferably 94% or more and 99.9% or less.

In the light reflection layer, the reflectance measured by the SCE method that excludes regular reflection light is preferably 10% or more and 80% or less, more preferably 15% or more and 80% or less. Setting the reflectance measured by the SCE method to such a range helps to reduce the increase in light intensity at a specific elevation angle by making the regular reflection light relatively less conspicuous. The reflectance measured by the SCE method can be measured by a spectrophotometer.

<Adhesive layer>

The adhesive layer can be used to laminate each member of the laminate to each other. In the case where the light reflection layer includes the electrodes included in the organic EL display element, the organic EL display element and the retardation film can be laminated via the adhesive layer. The adhesive layer can be composed of an adhesive composition such as (meth)acrylic, rubber, urethane, ester, polysiloxane, and polyvinyl ether. Resin as the main component. Among them, an adhesive composition having a (meth)acrylic resin excellent in transparency, weather resistance, heat resistance, and the like as a base polymer is preferable. The adhesive composition may be an active energy ray hardening type or a thermosetting type. The thickness of the adhesive layer is usually 3 to 30 μm, preferably 3 to 25 μm.

The (meth)acrylic resin (base polymer) used in the adhesive composition can be suitably used, for example: butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, for example , (meth)acrylic acid 2-ethylhexyl ester, such as (meth)acrylic acid ester, one or two or more kinds of polymers or copolymers as monomers. In the base polymer, it is preferable to copolymerize polar monomers. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, and N,N (meth)acrylate. - Monomers with carboxyl group, hydroxyl group, amide group, amine group, epoxy group, etc. such as dimethylamine ethyl ester and glycidyl (meth)acrylate.

The adhesive composition may contain only the above-mentioned base polymer, but usually further contains a cross-linking agent. The crosslinking agent can be exemplified as follows: a metal ion having a valence of 2 or more and forming a carboxylate metal salt with a carboxyl group; a polyamine compound and a carboxyl group forming an amide bond; a polyepoxy compound Or polyol, and form ester bond with carboxyl group; belong to polyisocyanate compound, and form amide bond with carboxyl group. Among them, polyisocyanate compounds are particularly preferred.

<Front Panel>

The front panel can be placed on the visible side of the polarizer. The front panel can be laminated on the polarizing plate through an adhesive layer. For the next layer, for example, the above-mentioned adhesive layer or adhesive layer can be exemplified.

As a front panel, what contains a hard-coat layer etc. on at least one surface of glass and a resin film is mentioned. As the glass, for example, high transmission glass or tempered glass can be used. Especially in the case of using thin transparent surface materials, chemically strengthened glass is preferred. The thickness of the glass can be set to, for example, 100 μm to 5 mm.

Before the panel is formed by including a hard coat layer on at least one side of the resin film, it may not be as rigid as conventional glass and may have flexible properties. The thickness of the hard coat layer is not particularly limited, and may be, for example, 5 to 100 μm.

The resin film may be a film formed of a polymer, the polymer being: a cycloolefin-based derivative having a unit of a cycloolefin-containing monomer such as norbornene or a polycyclic norbornene-based monomer; cellulose ( Cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose isobutyl ester, cellulose propionate, cellulose butyrate, cellulose acetate propionate) ethylene-vinyl acetate copolymer, polycyclic Olefin, polyester, polystyrene, polyamide, polyetherimide, polyacrylic acid, polyimide, polyamideimide, polyetherimide, polyether, polyethylene, polypropylene, polymethyl Pentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether dust, polymethyl methacrylate, polyethylene terephthalate , Polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, epoxy, etc. As the resin film, an unstretched film, a uniaxially stretched film, or a biaxially stretched film can be used. These macromolecules can be used individually or in mixture of 2 or more types, respectively. The resin film is preferably a polyimide film or a polyimide film excellent in transparency and heat resistance, a polyester film uniaxially or biaxially stretched, excellent in transparency and heat resistance, and can correspond to the film. Large-scale cycloolefin-based derivative films, polymethyl methacrylate films, and transparent and non-optically anisotropic cellulose triacetate and isobutyl cellulose films. The thickness of the resin film is 5 to 200 μm, preferably 20 to 100 μm.

<Shading pattern>

A light-shielding pattern (light-shielding screen) may be formed on the display element side of the front panel. The shading pattern can be set in such a way that each wiring of the display device is hidden from being viewed by the user. The color and/or material of the shading pattern is not particularly limited, and it can be formed of resin materials with various colors such as black, white, and gold. In one embodiment, the thickness of the light-shielding pattern may be in the range of 2 μm to 50 μm, preferably 4 μm to 30 μm, and more preferably 6 μm to 15 μm. Moreover, in order to suppress the mixing of air bubbles and the visual recognition of a boundary part by the level difference between a light-shielding pattern and a display part, a shape can be given to a light-shielding pattern.

<Production method of laminated body>

Hereinafter, the manufacturing method of the laminated body will be described by taking the laminated body 100 shown in FIG. 1 as an example. The laminated body 100 can be manufactured by laminating the polarizing plate, the retardation film 2 , and the light reflection layer 16 in this order, for example, via the 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 elongated members, attaching each member in a roll-to-roll manner, and then cutting into a predetermined shape, or by cutting each member into a predetermined shape. Afterwards, attach it again. Next, the adhesive layer 13 formed on the release film is laminated on the protective film 12 .

The retardation film 2 can be produced, for example, in the following manner. An alignment film is formed on a substrate, and a coating liquid containing a polymerizable liquid crystal compound is applied on the alignment film. The polymerizable liquid crystal compound is irradiated with active energy rays in a state after the polymerizable liquid crystal compound is oriented to harden the polymerizable liquid crystal compound. In this way, the film provided with the 1st retardation film 20 is produced. In the same manner, a film provided with the second retardation film 21 was produced.

The 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 orientation film are peeled off, respectively, and the retardation film 2 is produced. The retardation film 2 may be manufactured by preparing elongated members, laminating the members in a roll-to-roll manner, and then cutting them into a predetermined shape; combine. The retardation film 2 can be obtained by directly forming the second retardation film on the first retardation film. That is, the adhesive layer 15 may be omitted.

The release film on the adhesive layer 13 is peeled off, and the obtained polarizing plate and the retardation film 2 are pasted through the exposed adhesive layer 13 . The film obtained in this way can function as a circularly polarizing plate. When the light reflection layer 16 includes an electrode included in an organic EL display element, the laminate 100 of the present invention can be produced by laminating a circularly polarizing plate on the organic EL display element. This circularly polarizing plate is attached to the organic EL display element including the light reflection layer 16 through, for example, the adhesive layer 14 . The light reflection layer 16 has the characteristic represented by the formula (6) or the formula (8).

<Use>

The laminate of the present invention can be used in various display devices. A display device is a device having a display element, including a light-emitting element or a light-emitting device as a light-emitting source. Display devices include, for example, liquid crystal display devices, organic EL display devices, inorganic electroluminescence (hereinafter also referred to as inorganic EL) display devices, electron emission display devices (such as field emission display devices (Field Emission Display, also referred to as FED) ), surface electric field emission display device (also known as SED)), electronic paper (display device using electronic ink or electrophoresis element, plasma display device, projection display device (such as Grating Light Valve, also Called GLV) display device, display device with digital micromirror device (Digital Micromirror Device, also known as DMD) and piezoelectric ceramic display, etc. Liquid crystal display device also includes transmissive liquid crystal display device, transflective liquid crystal display Any of devices, etc. In particular, the laminate of the present invention can be effectively used in an organic EL display device or an inorganic EL display device.

In particular, the organic EL display device provided with the laminate of the present invention can suppress the color shift of the reflected light caused by the reflection of external light, and can exhibit a good black display capability even when viewed from an oblique direction.

[Example]

Hereinafter, the present invention will be described in more detail by way of examples. In addition, "%" and "part" in an example mean mass % and mass part unless otherwise specified.

(1) Measurement method of film thickness:

The thickness of the film was measured using an ellipsometer M-220 or a contact film thickness meter (MH-15M, counter TC101, MS-5C, manufactured by Nikon Co., Ltd.).

(2) Determination method of phase difference value:

The retardation value in the thickness direction and the in-plane retardation value were measured using KOBRA-WPR of Oji Scientific Instruments Co., Ltd. or ellipsometry M-220 manufactured by Nippon Shoko Co., Ltd.

(3) The reflected hue value observed from the direction of the elevation angle of 8°:

Measured using a spectrophotometer CM-2600d manufactured by Konica Minolta Co., Ltd.

(4) The reflected hue value observed from the direction of the elevation angle of 50°:

Measured by the display evaluation system DMS803 manufactured by Instrument Systems GmbH.

[Preparation of the light reflection layer]

The following 5 types of light reflection layers were used. Any light reflection layer has a flat reflection spectrum, and white or silver reflection light can be recognized.

Light reflection layer 1: NTK SUS 304B, a SUS plate manufactured by Nippon Metal Industries Co., Ltd.

Light reflection layer 2: The surface of the light reflection layer 1 is chrome-plated.

Light reflection layer 3: The glossy surface of My Foil Thick 50 of aluminum foil manufactured by UACJ Co., Ltd.

Light reflection layer 4: Non-glossy surface of My Foil Thick 50 of aluminum foil manufactured by UACJ Co., Ltd.

Light reflection layer 5: MIRO5 5011GP, an aluminum vapor-deposited reflector manufactured by Alanod, which is a high reflectance reflector.

The reflection characteristics of each light reflection layer are shown in the following table. Any reflectance is luminous factor corrected. Measurement was performed at an elevation angle of 8° using a spectrophotometer CM-2600d manufactured by Konica Minolta Co., Ltd.

[Table 1]

[Production of circular polarizer 1]

[Preparation of the composition for forming a horizontal alignment film]

5 parts (weight average molecular weight: 30000) of a photo-alignment material having the following structure and 95 parts of cyclopentanone (solvent) were mixed. The resulting mixture was stirred at 80° C. for 1 hour, whereby a composition for forming a horizontally aligned film was obtained.

[Preparation of composition for vertical alignment film formation]

Sunever SE610 manufactured by Nissan Chemical Industry Co., Ltd. was used.

[Preparation of the composition for forming a horizontally aligned liquid crystal cured film]

In order to form a horizontal alignment liquid crystal cured film (1st retardation film), the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B are used. The polymerizable liquid crystal compound A is produced by the method described in Japanese Patent Laid-Open No. 2010-31223. In addition, the polymerizable liquid crystal compound B is manufactured according to the method described in Unexamined-Japanese-Patent No. 2009-173893. The molecular structures of each are 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. To 100 parts of the obtained mixture, 1.0 part of a leveling agent (F-556; manufactured by DIC Co., Ltd.) and 2-dimethylamino-2-benzyl-1-(4-methylene chloride) were added as a polymerization initiator. 6 parts of olinylphenyl)butane-1-one (Irgacure 369, manufactured by BASF Japan Co., Ltd.). Then, N-methyl-2-pyrrolidone (NMP) was added so that solid content concentration might be 13%, and it stirred at 80 degreeC for 1 hour, and obtained the composition for horizontal alignment liquid crystal cured film formation.

[Preparation of a composition for forming a vertical alignment liquid crystal cured film]

In order to form a vertical alignment liquid crystal cured film (2nd retardation film), a composition was prepared by the following process. 0.1 part of F-556 as a leveling agent and 3 parts of Irgacure 369 as a polymerization initiator were added to 100 parts of Paliocolor LC242 (registered trademark of BASF Corporation) which is a polymerizable liquid crystal compound. Cyclopentanone was added so that solid content concentration might become 13%, and the composition for vertical alignment liquid crystal cured film formation was obtained.

[Production of polarizing plate]

A polyvinyl alcohol (PVA) film having an average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol % or more, and a thickness of 75 μm was prepared. The PVA film was immersed in pure water at 30°C, and then 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 subjected to the iodine dyeing step was immersed in an aqueous solution with a mass ratio of potassium iodide/boric acid/water of 12/5/100 at 56.5° C. for boric acid treatment (boric acid treatment step). The PVA film subjected to the boric acid treatment step was washed with pure water at 8° C., and then dried at 65° C. to obtain a polarizing film with iodine adsorption directed to polyvinyl alcohol. The extension of the PVA film is carried out in the iodine dyeing step and the boric acid treatment step. The total stretch magnification of the PVA film was 5.3 times. The thickness of the obtained polarizing film was 27 micrometers.

The polarizing film and the saponified cellulose triacetate (TAC) film (Konica Minolta Co., Ltd. KC4UYTAC thickness 40 μm) were bonded together by a nip roller via a water-based adhesive. While maintaining the tension of the obtained laminate at 430 N/m, drying was performed at 60° C. for 2 minutes to obtain a polarizing plate having a TAC film as a protective film on one side. In addition, the water-based adhesive was added to 100 parts of water by adding 3 parts of carboxy-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., "Kuraray Poval KL318"), and a water-soluble polyamide epoxy resin (Taoka Chemical Industry Co., Ltd. 1.5 parts of "Sumirez Resin 650", an aqueous solution with a solid concentration of 30%) was prepared.

The optical properties of the obtained polarizing plate were measured. The measurement was carried out by a spectroluminescence factor meter ("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 is consistent with the extending direction of the polyvinyl alcohol. The obtained polarizing plate has a luminous factor corrected monomer transmittance of 42.3%, a luminous factor corrected polarization degree of 99.996%, and a monomer hue a of -1.0. The monomer hue b was 2.7.

[Production of retardation film]

A corona treatment was applied to a cyclic olefin-based resin (COP) film (ZF-14-50) manufactured by Zeon Corporation. The corona treatment was performed using TEC-4AX manufactured by Ushio Electric Co., Ltd. The corona treatment was performed once under the conditions of an output of 0.78 kW and a treatment speed of 10 m/min. The composition for forming a horizontally aligned film was applied to a COP film by a bar coater, and dried at 80° C. for 1 minute. Using a polarizing UV irradiation device ("SPOT CURE SP-9", manufactured by Ushio Electric Co., Ltd.), the coating film was subjected to polarizing UV exposure at an axial angle of 45° so that the cumulative light intensity at a wavelength of 313 nm would be 100 mJ/cm ² . The film thickness of the obtained horizontally aligned film was 100 nm.

Next, the composition for horizontal alignment liquid crystal cured film formation was apply|coated to a horizontal alignment film using a bar coater, and it dried at 120 degreeC for 1 minute. Horizontal alignment was formed by irradiating the coating film with ultraviolet rays (in a nitrogen atmosphere, cumulative 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 Electric Co., Ltd.). Liquid crystal cured film (1st retardation film). The film thickness of the horizontally aligned liquid crystal cured film was 2.3 μm.

The adhesive is laminated on the horizontally aligned liquid crystal cured film. The film which consists of a COP film, an alignment film, and a horizontal alignment liquid crystal cured film is bonded to glass through this adhesive bond layer. The sample for measuring the retardation value was obtained by peeling the COP film.

When measuring the phase difference value RoA(λ) at each wavelength, the results are RoA(450)=121nm, RoA(550)=142nm, RoA(650)=146nm, RoA(450)/RoA(550)=0.85, RoA( 650)/RoA(550)=1.03, the horizontally oriented liquid crystal cured film system exhibits negative wavelength dispersion. The horizontally aligned liquid crystal cured film is a positive A plate satisfying the relation of nx>ny≒nz.

Further, when the retardation value RthA(λ) at each wavelength was measured, RthA(450)=61 nm, RthA(550)=71 nm, and RthA(650)=73 nm.

[Production of Vertically Aligned Liquid Crystal Cured Film]

Corona treatment was given to the horizontal orientation liquid crystal cured film in the film which consists of a COP film, an orientation film, and a horizontal orientation liquid crystal cured film produced above. Conditions for the corona treatment were the same as those described above. The composition for vertical alignment liquid crystal cured film formation was apply|coated on the horizontal alignment liquid crystal cured film by a bar coater, and it dried at 80 degreeC for 1 minute, and obtained the vertical alignment film. The film thickness of the obtained vertical alignment film was 50 nm.

The composition for vertical alignment liquid crystal cured film formation was apply|coated to a vertical alignment film using a bar coater, and it dried at 90 degreeC for 120 second. Vertical alignment was formed by irradiating the coating film with ultraviolet rays (in a nitrogen atmosphere, cumulative 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 Electric Co., Ltd.). Liquid crystal cured film (2nd retardation film). In this way, the film which consists of a COP film, a horizontal alignment film, a horizontal alignment liquid crystal cured film, a vertical alignment film, and a vertical alignment liquid crystal cured film is obtained. The film thickness of the vertically aligned liquid crystal cured film was 0.1 μm.

In order to measure the retardation value of the thickness direction of a vertical alignment liquid crystal cured film, a vertical alignment film and a vertical alignment liquid crystal cured film were separately formed on the COP film by the same process as the above. The adhesive is laminated on the vertical alignment liquid crystal cured film. The film consisting of a COP film, an alignment film, and a vertical alignment liquid crystal cured film is bonded to glass through the adhesive layer. The COP film was peeled off to obtain a sample for measuring the retardation value. The retardation value RthC(550) at the wavelength of 550nm was measured, and the result was RthC(550)=-20nm. The vertical alignment liquid crystal cured film is a positive C plate satisfying the relation of nx≒ny<nz.

Corona treatment is performed on the vertical alignment liquid crystal cured film in the film which consists of a COP film, a horizontal alignment film, a horizontal alignment liquid crystal cured film, a vertical alignment film, and a vertical alignment liquid crystal cured film. Conditions for the corona treatment were the same as those described above. Both are laminated through the adhesive layer so that the polarizing film and the vertical alignment liquid crystal cured film in the polarizing plate are brought into 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 aligned liquid crystal cured film was 45°. Finally, the COP film is peeled off to obtain the circular polarizing plate 1 in which the retardation film and the polarizing plate are laminated through the adhesive layer. This circular polarizing plate 1 is composed of layers of TAC film, polarizing film, adhesive layer, vertical alignment liquid crystal cured film, vertical alignment film, horizontal alignment liquid crystal cured film, and horizontal alignment film. |RthC(550)|/|RoA(550)|=0.14.

[Production of circular polarizer 2]

The circular polarizing plate 2 was produced in the same manner as the circular polarizing plate 1 except that the film thickness of the vertical alignment liquid crystal cured film was set to 0.3 μm and RthC(550)=−40 nm. |RthC(550)|/|RoA(550)|=0.28.

[Production of circular polarizer 3]

The circularly polarizing plate 3 was produced in the same manner as the circularly polarizing plate 1 except that the film thickness of the vertical alignment liquid crystal cured film was set to 0.4 μm and RthC(550)=−60 nm. |RthC(550)|/|RoA(550)|=0.42.

[Production of Circular Polarizing Plate 4]

The circularly polarizing plate 4 was produced in the same manner as the circularly polarizing plate 1 except that the film thickness of the vertical alignment liquid crystal cured film was set to 0.5 μm and RthC(550)=−71 nm. |RthC(550)|/|RoA(550)|=0.50.

[Production of circular polarizer 5]

The circularly polarizing plate 5 was produced in the same manner as in Example 1 except that the film thickness of the vertically aligned liquid crystal cured film was set to 0.6 μm and RthC(550)=−90 nm. |RthC(550)|/|RoA(550)|=0.63.

[Production of circular polarizer 6]

The circular polarizing plate 6 is produced in the same manner as the circular polarizing plate 1 except that the vertical alignment liquid crystal cured film is not produced. The circularly polarizing plate 6 has only a horizontal alignment liquid crystal cured film (1st retardation film) as a retardation film. |RthC(550)|/|RoA(550)|=0.

[Example 1]

In the circular polarizing plate, the adhesive layer is laminated on the surface exposed by peeling the COP film. The circularly polarizing plate 1 and the light reflection layer 1 are laminated through the adhesive layer to obtain a laminated body.

The oblique angle difference was measured about the obtained laminated body. Specifically, the in-plane angle of the laminated body was changed from the direction of the elevation angle of 50°, and each reflection hue value was measured by the display evaluation system DMS803. From the measured reflection hue value, calculate the reflection hue value at the in-plane angle at which the reflection hue value becomes the largest, and the reflection hue value at the angle obtained by adding 90° to the in-plane angle in the a*b* plane distance.

About the obtained laminated body, the hue at the time of changing the relationship between the optical axis of a horizontal alignment liquid crystal cured film and the position of an observer was observed visually. Specifically, the color of reflected light when visually observed from an elevation angle of around 50° at an in-plane angle parallel to the slow axis of the first retardation film, and an angle parallel to the fast axis of the first retardation film were evaluated. The color of reflected light when visually observed from an in-plane angle near an elevation angle of 50°. According to the following evaluation criteria, it is judged whether the contrast in the oblique direction is good or not.

Good: When viewed from an oblique direction, there is no chromatic aberration in the reflected light of the external light, and a good black display can be achieved.

Defect: When viewed from an oblique direction, there is a chromatic aberration in the reflected light system of external light, and it is difficult to achieve a good black display.

As a result, the oblique angular difference of the laminate obtained in Example 1 was 2, the color of the reflected light was uniform even when viewed from any direction, and it was found that a good black display could be realized at 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 reflection layer was changed to that shown in Table 2. In the same manner as in Example 1, the oblique angle difference was measured for the obtained laminate. Moreover, similarly to Example 1, the hue after changing the relationship between the optical axis of a horizontal alignment liquid crystal cured film and the position of an observer was visually observed about the obtained laminated body. The above results are shown in Table 2.

[Industrial Availability]

The layered product of the present invention can suppress color shift of reflected light due to external light reflection, and can impart good black display capability even when viewed from an oblique direction. The organic EL display device provided with the laminate of the present invention can suppress the color shift of the reflected light caused by the reflection of external light, and can exhibit a good black display capability even when viewed from an oblique direction.

2‧‧‧Retardation film

10‧‧‧Polarizing film

11, 12‧‧‧Protective film

13, 14‧‧‧Adhesive layer

15‧‧‧Additional layer

16‧‧‧Light Reflecting Layer

20‧‧‧First retardation film

21‧‧‧Second retardation film

100‧‧‧Laminate

Claims (5)

A laminated body, comprising in the order of a polarizing film, a retardation film and a light reflection layer: a circular polarizer having the polarizing film and the retardation film, and the light reflection layer; the retardation film having a first retardation film As with the second retardation film, the first retardation film has the characteristics represented by the formulae (1) to (3), the second retardation film has the characteristics represented by the formula (4), and the first retardation film has the characteristics expressed by the formula (4). The difference film and the second retardation film satisfy the relationship of the formula (5), and the light reflection layer has the characteristic 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 formula, nx represents the refractive index in the direction of the slow axis in the film plane, ny represents the refractive index in the direction in the film plane and orthogonal to the slow 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 λnm, RthC(λ) represents the retardation value of the second retardation film in the thickness direction at a wavelength of λnm, and Yref represents the luminous factor corrected reflectance . A laminated body comprising, in the order of a polarizing film, a retardation film and a light reflection layer: a circular polarizer having the polarizing film and the retardation film, and the light reflection layer; The retardation film has a first retardation film and a second retardation film, the first retardation film has characteristics represented by formulas (1) to (3), and the second retardation film has the characteristics expressed by formula (4) ), the first retardation film and the second retardation film satisfy the relationship of the formula (7), and the light reflection layer has the characteristic expressed 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 formula, nx represents the refractive index in the direction of the slow axis in the film plane, ny represents the refractive index in the direction perpendicular to the slow axis in the film plane, 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 λnm, and RthC(λ) represents the thickness direction phase of the second retardation film at a wavelength of λnm The difference, Yref represents the luminous factor corrected reflectance. An organic electroluminescence display device comprising the laminate described in claim 1 or 2 of the scope of the application, and when viewed from an oblique angle with an elevation angle of 50° during black display, the reflection hue value becomes the largest at the in-plane angle. The slant angle difference between the reflection hue value of , and the reflection hue value at the angle after adding 90° to the in-plane angle in the a*b* plane is less than 4. A use of a circularly polarizing plate, which is used to adhere to a light reflection layer having the characteristics represented by the formula (6), the circularly polarizing plate is provided with a polarizing film and a retardation film, and the retardation film has a first retardation film and the second retardation film, the first retardation film has the characteristics represented by the formula (1) to the formula (3), the second retardation film has the characteristic represented by the formula (4), the first retardation film The retardation film and the second retardation film system satisfy the relationship of formula (5), 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 formula, nx represents the in-plane of the film The refractive index in the slow axis direction, ny represents the refractive index in the film plane and in the direction orthogonal to the slow axis, nz represents the refractive index in the thickness direction of the film, and RoA (λ) represents the first retardation film at a wavelength of λnm. The in-plane retardation value, RthC(λ) represents the retardation value in the thickness direction of the second retardation film at wavelength λnm, and Yref represents the luminous factor corrected reflectance. The purpose of a circular polarizing plate is to adhere to a light reflection layer having the characteristics represented by the formula (8). The circular polarizing plate is provided with a polarizing film and a retardation film, The retardation film has a first retardation film and a second retardation film, the first retardation film has characteristics represented by formulas (1) to (3), and the second retardation film has the characteristics expressed by formula (4) ), the first retardation film and the second retardation film satisfy the relationship of the formula (7), 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) at In each formula, nx represents the refractive index in the direction of the slow axis in the film plane, ny represents the refractive index in the direction perpendicular to the slow axis in the film plane, nz represents the refractive index in the thickness direction of the film, and RoA(λ) represents The in-plane retardation value of the first retardation film at wavelength λnm, RthC(λ) represents the retardation value of the second retardation film in the thickness direction at wavelength λnm, and Yref represents the luminous factor corrected reflectance.

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