KR20190091451A - Circular polarizer - Google Patents

Abstract

(Problem) To provide a circular polarizing plate which is excellent in antireflection characteristics and can be manufactured at low cost.
(Solution means) The circularly polarizing plate of the present invention is a circularly polarizing plate including a polarizer, a retardation layer 20a functioning as a λ / 4 plate, and a colored layer in this order, and the absorption axis of the polarizer and the retardation layer 20a. The slow axis of the ()) is 35 ° to 55 °, the polarization degree of the laminate formed of the polarizer and the colored layer is 99.9% or more. In one embodiment, the said colored layer selectively absorbs the light of a specific wavelength range.

Description

Circular polarizer

The present invention relates to a circular polarizing plate.

Recently, smart devices, such as smart phones, and display devices such as digital signage and window displays have been increasingly used under strong external light. As a result, problems such as reflection of external light and overlapping of the background caused by a reflector such as a touch panel part, a glass substrate, and a metal wire used in the display device itself or the display device have arisen. Therefore, it is known to prevent these problems by providing a circularly polarizing plate having a λ / 4 plate on the viewer side. As a general circular polarizing plate, a retardation film (typically λ / 4 plate) represented by a cycloolefin (COP) -based resin film is laminated so that its ground axis forms an angle of about 45 ° with respect to the absorption axis of the polarizer. It is known. It is known that the retardation film of COP system resin does not depend on the wavelength of a measurement light, but has a substantially constant so-called flat wavelength dispersion characteristic. When a circularly polarizing plate including a retardation film having such a flat wavelength dispersion characteristic is used for a display device, there is a problem that excellent reflection color is not obtained.

In order to solve the above problems, a circularly polarizing plate containing a retardation film having a wavelength dependency (reverse dispersion wavelength characteristic) of so-called reverse dispersion in which the retardation value increases with the wavelength of the measurement light has been proposed (for example, Patent Document 1). ). However, the use of a retardation film having reverse dispersion wavelength characteristics is disadvantageous in terms of cost. Moreover, when applying to the reflector with high reflectance, there also exists a problem that color adjustment is especially difficult.

Japanese Patent Publication No. 2006-171235

This invention is made | formed in order to solve the said conventional subject, The main objective is to provide the circularly-polarizing plate which is excellent in antireflection characteristic and can be manufactured at low cost.

The circularly polarizing plate of the present invention is a circularly polarizing plate having a polarizer, a retardation layer 20a functioning as a λ / 4 plate, and a colored layer in this order, and the absorption axis of the polarizer and the slow axis of the retardation layer 20a. This angle is 35 degrees-55 degrees, and the polarization degree of the laminated body which consists of the said polarizer and the said colored layer is 99.9% or more.

In one embodiment, the circular polarizing plate further includes a phase difference layer 20b functioning as a λ / 2 plate between the polarizer and a phase difference layer 20a functioning as the λ / 4 plate, and absorbs the polarizer. The angle between the axis and the phase difference layer 20a is 65 ° to 85 °, and the angle between the absorption axis of the polarizer and the phase difference layer 20b is 10 ° to 20 °.

In one embodiment, the said colored layer selectively absorbs the light of a specific wavelength range.

In one embodiment, the said colored layer has absorption maximum wavelength in the wavelength range of 440 nm-510 nm.

In one embodiment, the said colored layer has absorption maximum wavelength in the wavelength range of 560 nm-610 nm.

In one embodiment, the haze value of the said colored layer is 15% or less.

In one embodiment, the polarization degree of the said polarizer is 99.9% or more.

In one embodiment, Re (450) / Re (550) of the retardation layer 20a which functions as said (lambda) / 4 board is 0.5 or more and less than 1.0, and the Nz coefficient of the retardation layer 20a is 0.3-0.7. .

In one embodiment, the circular polarizing plate has a low reflection treatment layer on the outermost surface.

According to another situation of this invention, an image display apparatus is provided. This image display device includes the circular polarizing plate.

In one embodiment, the image display apparatus further includes an image display panel, and the visible light reflectance of the image display panel is 20% or more.

(Effects of the Invention)

According to the present invention, a circularly polarizing plate excellent in antireflection characteristics can be obtained by forming a colored layer. In addition, the circularly polarizing plate of the present invention can emit light having a neutral color by adjusting the reflection color by appropriately setting the absorption wavelength of the colored layer. In addition, when the circularly polarizing plate of the present invention is used, wide color gamut of an image display device is enabled.

1 is a schematic cross-sectional view of a circular polarizing plate according to one embodiment of the present invention.
2 is a schematic cross-sectional view of a circular polarizing plate according to another embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although preferred embodiment of this invention is described, this invention is not limited to these embodiment.

(Definitions of terms and symbols)

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

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

"Nx" is the refractive index of the direction in which the in-plane refractive index is maximum (that is, the slow axis direction), "ny" is the refractive index of the direction orthogonal to the slow axis (that is, the true axis direction) in-plane, "Nz" is a refractive index in the thickness direction.

(2) In-plane phase difference (Re)

"Re ((lambda))" is an in-plane retardation measured with light having a wavelength of λ nm at 23 ° C. For example, "Re (550)" is an in-plane retardation measured with light having a wavelength of 550 nm at 23 ° C. Re (λ) is obtained by the formula: Re = (nx−ny) × d when the thickness of the layer (film) is d (nm).

(3) phase difference (Rth) in thickness direction

"Rth ((lambda))" is a phase difference of the thickness direction measured with the light of wavelength (lambda) nm in 23 degreeC. For example, "Rth (550)" is a phase difference of the thickness direction measured with the light of wavelength 550nm in 23 degreeC. Rth (λ) is obtained by the formula: Rth = (nx−nz) × d when the thickness of the layer (film) is d (nm).

(4) Nz coefficient

Nz coefficient is calculated | required by Nz = Rth / Re.

A. Circular polarizer

A-1. Overall composition of circular polarizer

1 is a schematic cross-sectional view of a circular polarizing plate according to one embodiment of the present invention. The circularly polarizing plate 100 of the present embodiment includes a polarizer 10, a phase difference layer 20a, and a colored layer 30 in this order. The phase difference layer 20a can function as a λ / 4 plate. The circular polarizing plate 100 can be used such that the colored layer 30 is on the reflector side (for example, an image display panel such as a liquid crystal display panel or an organic EL panel) and the polarizer 10 is on the viewing side. In one embodiment, the circular polarizing plate 100 is equipped with the protective film 40 in the surface on the opposite side to the phase difference layer 20a of the polarizer 10. The protective film 40 may be omitted depending on the use, the configuration of the image display device including the circular polarizing plate, and the like. In addition, the circular polarizing plate may be provided with a separate protective film (also called an inner protective film: not shown) between the polarizer and the retardation layer. In the illustrated example, the inner protective film is omitted. In this case, the retardation layer 20a can also function as an inner protective film. With such a configuration, new thinning of the circular polarizing plate can be realized.

In this embodiment, the angle formed between the absorption axis of the polarizer 10 and the slow axis of the phase difference layer 20a is 35 ° to 55 °, preferably 38 ° to 52 °, and more preferably 40 ° to 50 °. °, More preferably, it is 42 degrees-48 degrees, Especially preferably, it is 44 degrees-46 degrees. If the angle is in this range, the desired circular polarization function can be realized. In addition, when mentioning an angle in this specification, the angle includes the angle of both directions clockwise and counterclockwise unless it mentions specially.

The circularly polarizing plate of the present invention is typically disposed on the viewing side of the image display device and can function as an antireflection film. The circularly polarizing plate of the present invention includes a colored layer, and the colored layer exhibits excellent antireflection function by absorbing light of a specific wavelength. The circular polarizing plate of the present invention can sufficiently block the reflected light from the reflector even when applied to a reflector having a high reflectance (for example, reflectance of 15% or more). Further, by selectively absorbing the light in the specific wavelength range, the colored layer can appropriately adjust the reflection color and obtain a polarizing plate that can contribute to the wide color gamut of the image display device (a detailed description will be described later). In addition, what wavelength of light the colored layer absorbs can be appropriately adjusted according to the reflection characteristics of a reflector (for example, an image display panel such as a liquid crystal display panel, an organic EL panel) to which the circularly polarizing plate is applied.

2 is a schematic cross-sectional view of a circular polarizing plate according to another embodiment of the present invention. The circular polarizing plate 100 'further includes a separate retardation layer 20b between the polarizer 10 and the retardation layer 20a (λ / 4 plate). The other retardation layer 20b functions as a lambda / 2 plate. In addition, in this specification, for convenience, the phase difference layer 20a ((lambda / 4) plate) may be called a 1st phase difference layer, and the other phase difference layer 20b ((lambda / 2 plate)) may be called a 2nd phase difference layer. The circularly polarizing plate 100 ′ of the illustrated example includes a protective film 30 on the side opposite to the other retardation layer 20b of the polarizer 10. In addition, the circular polarizing plate may be provided with a separate protective film (also called an inner protective film: not shown) between the polarizer and the retardation layer. In the illustrated example, the inner protective film is omitted. In this case, another retardation layer (second retardation layer) 20b can also function as an inner protective film.

In this embodiment, the angle between the absorption axis of the polarizer 10 and the slow axis of the first retardation layer 20a is preferably 65 ° to 85 °, more preferably 72 ° to 78 °, further preferably It is about 75 °. The angle between the absorption axis of the polarizer 10 and the slow axis of the second retardation layer 20b is preferably 10 ° to 20 °, more preferably 13 ° to 17 °, still more preferably about 15 °. By arranging the two retardation layers at the same axial angle as described above, a circularly polarizing plate having very excellent circularly polarized light characteristic (as a result, very good antireflection property) in a wide band is obtained.

In one embodiment, the circularly polarizing plate of this invention does not have the said phase difference layer which can function as a (lambda) / 4 plate, and other phase difference layers other than the said phase difference which can function as a (lambda) / 2 plate. The circular polarizing plate of the present invention can be manufactured at low cost because it can have excellent antireflection function, color adjustment function, and wide color gamut function without having any other phase difference layer.

The polarization degree of the laminated body x comprised from the said polarizer and the said colored layer is 99.9% or more, Preferably it is 99.95% or more, More preferably, it is 99.99% or more. The laminated body x is obtained by producing the polarizer similar to the polarizer and colored layer which comprise a circularly-polarizing plate, and colored layer, and laminating them. The laminated body x may have another layer (for example, a protective film) which does not affect polarization degree. In one embodiment, by forming the colored layer with a low haze value, polarization cancellation of the light which permeate | transmits the said colored layer is suppressed, and the polarization degree of the laminated body x can be made high. When the polarizer and colored layer which comprise the laminated body x with high polarization degree are used, the circularly-polarizing plate which exhibits the outstanding antireflection function can be obtained. The upper limit of the polarization degree of the laminated body x is 99.999%, for example. The measuring method of the polarization degree of the laminated body x is mentioned later.

In one embodiment, the circularly polarizing plate is subjected to low reflection treatment on the outermost surface (for example, the surface to be the viewing side) and has a low reflection treatment layer on the outer surface. As the low reflection treatment, a method of forming a thin film by bonding a antireflection film or a resin having a low refractive index such as fluorine or hollow silica by a wet process (wet method) such as coating or coating (for example, a patent document: Japanese Patent Application Laid-Open No. 2013-64934), and a multilayer antireflection film obtained by combining a dry process and a wet process (wet method) such as coating or coating (for example, Patent Document: Japanese Patent Laid-Open No. 2002-243906) Can be mentioned.

A-2. Polarizer and protective film

Arbitrary appropriate polarizers are used as said polarizer. The polarizer may be an absorption type, a reflection type, or a combination of an absorption type and a reflection type. For example, uniaxial stretching is carried out by adsorbing dichroic substances such as iodine or dichroic dye onto hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene-vinyl acetate copolymerized partial saponified films. And polyene-based alignment films such as dehydrated products of polyvinyl alcohol and dehydrochloric acid treated products of polyvinyl chloride. Among these, the polarizer which uniaxially stretched by adsorb | sucking dichroic substances, such as iodine, on a polyvinyl alcohol-type film has a high polarization dichroic ratio, and is especially preferable. The thickness of the polarizer is preferably 0.5 µm to 80 µm.

The polarizer which uniaxially stretched by adsorbing iodine to a polyvinyl alcohol-type film is typically produced by dyeing polyvinyl alcohol by immersion in an aqueous solution of iodine, and stretching the film to 3 to 7 times its original length. Stretching may be performed after dyeing, stretching while dyeing, or dyeing after stretching. In addition to stretching and dyeing, for example, treatments such as swelling, crosslinking, adjustment, washing with water, drying and the like are carried out and produced. For example, before dyeing, the polyvinyl alcohol-based film is immersed in water and washed to prevent contamination of the polyvinyl alcohol-based film or an antiblocking agent, and the polyvinyl alcohol-based film is swollen to prevent dyeing unevenness. Can be. The polyvinyl alcohol-based film may be a single layer film (normal film-formed film) or may be a polyvinyl alcohol-based resin layer coated on a resin substrate. Techniques for producing a polarizer from a monolayer polyvinyl alcohol-based film are well known in the art. The technique of manufacturing a polarizer from the polyvinyl alcohol-type resin layer apply | coated and formed on the resin base material is described, for example in Unexamined-Japanese-Patent No. 2009-098653.

The polarizer preferably shows absorption dichroism at any one of wavelengths of 380 nm to 780 nm. The single transmittance of the polarizer is preferably 38% to 45.5%, more preferably 40% to 45%.

The polarization degree of the polarizer is preferably 99.9% or more, and more preferably 99.95% or more. If it is this range, a desired circularly polarizing function will be exhibited and the circularly polarizing plate excellent in antireflection characteristic can be obtained.

Arbitrary suitable films are used as said protective film. As a specific example of the material used as a main component of such a film, cellulose resins, such as triacetyl cellulose (TAC), (meth) acrylic-type, polyester type, polyvinyl alcohol type, polycarbonate type, polyamide type, polyimide type, polyether And transparent resins such as sulfone series, polysulfone series, polystyrene series, polynorbornene series, polyolefin series, and acetate series. Moreover, thermosetting resins, such as an acryl-type, urethane type, an acryl urethane type, an epoxy type, a silicone type, or ultraviolet curable resin, etc. are mentioned. In addition, glassy polymers, such as a siloxane polymer, are mentioned, for example. Moreover, the polymer film of Unexamined-Japanese-Patent No. 2001-343529 (WO 01/37007) can also be used. As a material of this film, the resin composition containing the thermoplastic resin which has a substituted or unsubstituted imide group in a side chain, and the thermoplastic resin which has a substituted or unsubstituted phenyl group and a nitrile group in a side chain can be used, for example, an iso part The resin composition which has the alternating copolymer which consists of ten and N-methyl maleimide, and an acrylonitrile styrene copolymer is mentioned. The polymer film may be, for example, an extrusion molded product of the resin composition. Arbitrary suitable adhesive layers or an adhesive bond layer is used for lamination | stacking of a polarizer and a protective film. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive. The adhesive layer is typically formed of a polyvinyl alcohol-based adhesive.

A-3. First retardation layer (retardation layer functioning as λ / 4 plate)

The first retardation layer can function as a λ / 4 plate as described above. In-plane phase difference Re (550) of such a 1st phase difference layer is 100 nm-180 nm, Preferably it is 110 nm-170 nm, More preferably, it is 120 nm-160 nm, Especially preferably, it is 135 nm-155 nm to be. The first retardation layer typically has a refractive index ellipsoid of nx> ny = nz or nx> ny> nz. In addition, in this specification, for example, "ny = nz" includes not only exactly the same but also substantially the same. Nz coefficient of a 1st phase difference layer is 0.9-2, for example, Preferably it is 1-1.5, More preferably, it is 1-1.3.

The thickness of the first retardation layer may be set to function most appropriately as a λ / 4 plate. In other words, the thickness can be set such that a desired in-plane retardation is obtained. Specifically, the thickness is preferably 10 µm to 80 µm, more preferably 10 µm to 60 µm, and most preferably 30 µm to 50 µm.

The first retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases with the wavelength of the measurement light, the retardation value may exhibit a positive wavelength dispersion characteristic in which the retardation value decreases with the wavelength of the measurement light, and the retardation value may correspond to the wavelength of the measurement light. A flat wavelength dispersion characteristic which hardly changes even may be exhibited.

In one embodiment, the said 1st phase difference layer shows flat wavelength dispersion characteristic. By employing the first retardation layer exhibiting flat wavelength dispersion characteristics, excellent antireflection characteristics and reflection colors in the oblique direction can be realized. In addition, the circularly polarizing plate of the present invention can realize excellent reflection color even when a first retardation layer exhibiting flat wavelength dispersion characteristics is used. The circularly polarizing plate using the first retardation layer exhibiting flat wavelength dispersion characteristics is advantageous in terms of cost. In the present embodiment, Re (450) / Re (550) of the first retardation layer is preferably 0.99 to 1.03, and Re (650) / Re (550) is preferably 0.98 to 1.02.

In another embodiment, the first retardation layer exhibits reverse dispersion wavelength characteristics. By employing the first retardation layer exhibiting the reverse dispersion wavelength characteristic, the reflection color can be improved in the front direction. In addition, by adopting the first retardation layer exhibiting the reverse dispersion wavelength characteristic, it is possible to improve other characteristics (for example, luminance) while maintaining the practical reflection color. In this embodiment, Re (450) / Re (550) of a 1st phase difference layer becomes like this. Preferably it is 0.5 or more and less than 1.0, More preferably, it is 0.7-0.95. In addition, Re (650) / Re (550) of a 1st phase difference layer becomes like this. Preferably it is more than 1 and is 1.2 or less, More preferably, it is 1.01-1.15. In this embodiment, the Nz coefficient of a 1st phase difference layer becomes like this. Preferably it is 0.3-0.7, More preferably, it is 0.4-0.6, More preferably, it is 0.45-0.55, Especially preferably, it is about 0.5. If the Nz coefficient is within this range, better reflection colors can be achieved.

The λ / 4 plate is preferably a stretched film of a polymer film. Specifically, the λ / 4 plate is obtained by appropriately selecting the type of polymer and the stretching treatment (for example, stretching method, stretching temperature, stretching ratio, stretching direction).

Arbitrary suitable resin is used as resin which forms the said polymer film. As a specific example, resin which comprises birefringent film of quantities, such as cycloolefin resin, polycarbonate resin, cellulose resin, polyvinyl alcohol resin, polysulfone resin, such as polynorbornene, is mentioned. Especially, norbornene-type resin and polycarbonate-type resin are preferable. In addition, the detailed description of resin which forms a polymer film is described, for example in Unexamined-Japanese-Patent No. 2014-010291. The above description is incorporated herein by reference.

The said polynorbornene means the (co) polymer obtained using the norbornene-type monomer which has a norbornene ring in one part or all part of a starting material (monomer). As said norbornene-type monomer, for example, norbornene and its alkyl and / or alkylidene substituents, for example 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene Polar group substituents such as halogens such as nene, 5-butyl-2-norbornene and 5-ethylidene-2-norbornene; Dicyclopentadiene, 2,3-dihydrodicyclopentadiene and the like; Polar group substituents such as dimethanooctahydronaphthalene, alkyl and / or alkylidene substituents thereof, and halogens such as 6-methyl-1,4: 5,8-dimethano-1,4,4a, 5, 6,7,8,8a-octahydronaphthalene, 6-ethyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6- Ethylidene-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano -1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a, 5,6,7, 8,8a-octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarb Carbonyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene and the like; 3-4 tetramers of cyclopentadiene, for example 4,9: 5,8-dimethano-3a, 4,4a, 5,8,8a, 9,9a-octahydro-1H-benzoindene, 4 , 11: 5,10: 6,9-trimethano-3a, 4,4a, 5,5a, 6,9,9a, 10,10a, 11,11a-dodecahydro-1H-cyclopentaanthracene and the like. Can be mentioned.

Various products are commercially available as the polynorbornene. Specific examples include trade names "ZEONEX" manufactured by Zeon Corporation, "ZEONOR", trade name "Aton" manufactured by JSR Corporation, trade name "TOPAS" manufactured by Ticona Corporation, and trade name "APEL" manufactured by Mitsui Chemicals, Inc. have.

As said polycarbonate resin, Preferably, aromatic polycarbonate is used. Aromatic polycarbonates are typically obtained by the reaction of carbonate precursors and aromatic dihydric phenol compounds. Specific examples of the carbonate precursor include phosgene, bischloroformates of dihydric phenols, diphenyl carbonate, di-p-tril carbonate, phenyl-p-tril carbonate, di-p-chlorophenyl carbonate, dinaphthyl carbonate and the like. Can be. Among these, phosgene and diphenyl carbonate are preferable. Specific examples of the aromatic divalent phenol compound include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane and bis (4-hydroxyphenyl) Methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) butane, 2,2-bis (4-hydroxy-3,5-dipropylphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3 , 3,5-trimethylcyclohexane and the like. You may use these individually or in combination of 2 or more types. Preferably 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5 -Trimethylcyclohexane is used. In particular, it is preferable to use both 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

As a extending | stretching method, transverse uniaxial stretching, fixed end biaxial stretching, and sequential biaxial stretching are mentioned, for example. As a specific example of fixed edge biaxial stretching, the method of extending | stretching a polymer film in the width direction (horizontal direction), running in a longitudinal direction is mentioned. This method can be transverse uniaxial stretching in appearance. Inclined stretching may also be employed. By employ | adopting diagonal stretch, the elongate stretched film which has the orientation axis (ground axis) of predetermined angle with respect to the width direction can be obtained.

The thickness of the stretched film is typically 5 µm to 80 µm, preferably 15 µm to 60 µm, and more preferably 25 µm to 45 µm.

A-4. Second retardation layer (retardation layer functioning as λ / 4 plate)

The second retardation layer can function as a lambda / 2 plate as described above. The in-plane retardation Re (550) of the second retardation layer is preferably 180 to 300 nm, more preferably 210 to 280 nm, and most preferably 230 to 240 nm. It is preferable that the second retardation layer typically has a refractive index ellipsoid of nx> ny = nz. Nz coefficient of a 2nd phase difference layer is 0.9-2, for example, Preferably it is 1-1.5, More preferably, it is 1-1.3.

The thickness of the second retardation layer may be set to function most appropriately as a λ / 2 plate. In other words, the thickness can be set such that a desired in-plane retardation is obtained. Specifically, the thickness is preferably 0.5 µm to 5 µm, more preferably 1 µm to 4 µm, and most preferably 1.5 µm to 3 µm.

As a material of a said 2nd phase difference layer, arbitrary appropriate materials can be employ | adopted as long as the above characteristics are acquired. A liquid crystal material is preferable, and a liquid crystal material (nematic liquid crystal) whose liquid crystal phase is a nematic phase is more preferable. The difference between nx and ny of the 2nd phase difference layer obtained by using a liquid crystal material can be enlarged especially compared with a non-liquid crystal material. As a result, the thickness of the second retardation layer for obtaining the desired in-plane retardation can be made particularly small. As such a liquid crystal material, a liquid crystal polymer or a liquid crystal monomer can be used, for example. The liquid crystalline expression mechanism of the liquid crystal material may be either lyotropic or thermotropic. Moreover, it is preferable that the orientation state of a liquid crystal is homogeneous orientation. Moreover, you may use resin which forms the said polymer film as a material of a 2nd phase difference layer.

The second retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases with the wavelength of the measurement light, may exhibit a positive wavelength dispersion characteristic in which the retardation value decreases with the wavelength of the measurement light, and the retardation value may correspond to the wavelength of the measurement light. A flat wavelength dispersion characteristic which hardly changes even may be exhibited. It is preferable to exhibit flat wavelength dispersion characteristics. By adopting the λ / 2 plate having the flat wavelength dispersion characteristic, excellent antireflection characteristics and reflection colors in the oblique direction can be realized. Re (450) / Re (550) of the retardation layer is preferably 0.99 to 1.03, and Re (650) / Re (550) is preferably 0.98 to 1.02.

A-5. Colored layer

The colored layer comprises any suitable one or more color materials. Typically, a color material exists in a matrix in a colored layer.

In one embodiment, the colored layer selectively absorbs light in a specific wavelength range (that is, has an absorption maximum wavelength in a specific range of wavelength bands). In another embodiment, the colored layer functions to absorb the full wavelength of the visible light region. Preferably the colored layer selectively absorbs light in a particular wavelength range. When the colored layer is formed by selectively absorbing light in a specific wavelength range, the antireflection function can be enhanced while suppressing a decrease in visible light transmittance (that is, a decrease in luminance). In addition, by adjusting the wavelength of the light to be absorbed, the reflected color can be neutralized, and a circularly polarizing plate with little coloration can be obtained.

In one embodiment, the said colored layer has absorption maximum wavelength in the wavelength range of 440 nm-510 nm. When such a colored layer is formed, a reflection color can be adjusted suitably and a circularly polarizing plate with less coloring can be obtained.

In another embodiment, the said colored layer has absorption maximum wavelength in the wavelength range of 560 nm-610 nm. When such a colored layer is formed, a reflection color can be adjusted suitably and a circularly polarizing plate with less coloring can be obtained.

Moreover, in another embodiment, the said colored layer has absorption maximum wavelength in the wavelength range of 440 nm-510 nm and 560 nm-610 nm. With such a configuration, the mixing of the red light and the green light and the green light and the blue light can be satisfactorily prevented. When the circularly polarizing plate configured as described above is used as the antireflection film of the image display device, the wide color gamut of the image display device becomes possible, and bright and clear image quality can be obtained. According to the present invention, an image display device can be markedly wide gamut without using expensive technologies (organic EL technology, quantum dot technology). In other words, by combining the circularly polarizing plate of the present invention with a liquid crystal display panel, a wide color gamut equivalent to (or equivalent to) an image display device constructed by organic EL technology or quantum dot technology can be realized at low cost. It goes without saying that the circular polarizing plate of the present invention can be combined with an organic EL technology, a quantum dot technology, or the like to achieve a new wide color gamut. A colored layer having two or more absorption maximum wavelengths as described above can be obtained by using a plurality of color materials.

The transmittance at the absorption maximum wavelength of the colored layer is preferably 0% to 80%, more preferably 0% to 70%. If it is such range, the said effect of this invention will become more remarkable.

The visible light transmittance of the colored layer is preferably 30% to 90%, more preferably 30% to 80%. Within this range, a circularly polarizing plate capable of exhibiting an antireflection function while suppressing a decrease in luminance can be obtained.

Haze value of the said colored layer becomes like this. Preferably it is 15% or less, More preferably, it is 10% or less, More preferably, it is 5% or less. By putting the haze value of a colored layer in this range, the polarization cancellation of circularly polarized light which permeate | transmitted the said 1st phase difference layer (and 2nd phase difference layer) is prevented, and as a result, the circularly polarizing plate which has the outstanding antireflection characteristic can be obtained. Although the haze value of a colored layer is so preferable that it is small, the minimum is 0.1%, for example.

The thickness of the colored layer is preferably 1 µm to 100 µm, more preferably 2 µm to 30 µm.

A-5-1.Color material

Specific examples of the colorant include anthraquinone series, triphenylmethane series, naphthoquinone series, thioindigo series, perinone series, perylene series, squarylium series, cyanine series, porphyrin series, azaporphyrin series, phthalocyanine series, subphthalocyanine series, quinini Jarin-based, polymethine-based, rhodamine-based, oxonol-based, quinone-based, azo-based, xanthene-based, azomethine-based, quinacridone-based, dioxazine-based, diketopyrrolopyrrole-based, anthrapyridone-based, isoindolinone-based, indanthrone And dyes such as indigo, thioindigo, quinophthalone, quinoline, and triphenylmethane.

In one embodiment, dyes of anthraquinone series, oxime series, naphthoquinone series, quinizaline series, oxonol series, azo series, xanthene series or phthalocyanine series are used as colorants. When these dyes are used, the colored layer which has an absorption maximum wavelength in the wavelength range of 440 nm-510 nm can be formed.

In one embodiment, the indigo type, rhodamine type, quinacridone type, or porphyrin type dye is used for the colored layer which has an absorption maximum wavelength in the said range as a color material, for example. When these dyes are used, the colored layer which has an absorption maximum wavelength can be formed in the wavelength range of 560 nm-610 nm.

Moreover, you may use a pigment as said color material. As a specific example of a pigment, a black pigment (carbon black, bone black, graphite, iron black, titanium black, etc.), an azo pigment, a phthalocyanine pigment, a polycyclic pigment (quinacridone system, perylene system, perinone system, isoin, for example) Dolinone series, isoindolin series, dioxazine series, thioindigo series, anthraquinone series, quinophthalone series, metal complexes, diketopyrrolopyrrole series, etc. Zinc, zinc sulfide, clay, talc, barium sulfate, calcium carbonate, etc., rapeseed pigments (sulphur, cadmium, chromium vermilion, nickel titanium, chromium titanium, yellow iron oxide, bengal, zinc chromate, podium, ultramarine blue, blue, cobalt Blue, chrome green, chromium oxide, bismuth vanadate, and the like, bright pigments (pearl pigments, aluminum pigments, bronze pigments and the like), fluorescent pigments (zinc emulsion, strontium sulfide, strontium aluminate) and the like.

The content ratio of the color material may be any appropriate ratio depending on the kind of the color material, the desired light absorption characteristics, and the like. The content rate of the said color material is 0.01 weight part-100 weight part with respect to 100 weight part of matrix materials, More preferably, they are 0.01 weight part-50 weight part.

When using a pigment as a color material, the number average particle diameter of the said pigment in a matrix becomes like this. Preferably it is 500 nm or less, More preferably, it is 1 nm-100 nm. If it is such a range, a colored layer with a small haze value can be formed. The number average particle diameter of a pigment is measured and calculated by cross section observation of a colored layer.

A-5-2. matrix

An adhesive may be sufficient as a matrix, and a resin film may be sufficient as it. Preferably it is an adhesive.

When the matrix is an adhesive, any suitable pressure sensitive adhesive can be used as the pressure sensitive adhesive. The adhesive preferably has transparency and optical isotropy. As a specific example of an adhesive, a rubber-type adhesive, an acrylic adhesive, a silicone adhesive, an epoxy adhesive, and a cellulose adhesive are mentioned. Preferably it is a rubber adhesive or an acrylic adhesive.

The rubber polymer of a rubber adhesive (adhesive composition) is a polymer which shows rubber elasticity in the temperature range near room temperature. Preferred rubber polymers (A) include styrene thermoplastic elastomers (A1), isobutylene polymers (A2), and combinations thereof.

As the styrene-based thermoplastic elastomer (A1), for example, styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS) , Styrene-ethylene-propylene-styrene block copolymer (SEPS, SIS hydrogenated product), styrene-ethylene-propylene block copolymer (SEP, hydrogenated styrene-isoprene block copolymer), styrene-isobutylene-styrene block Styrene-type block copolymers, such as a copolymer (SIBS) and styrene butadiene rubber (SBR), are mentioned. Among them, a styrene-ethylene-propylene-styrene block copolymer (SEPS, SIS hydrogenated) and a styrene-ethylene-butylene-styrene block copolymer have polystyrene blocks at both ends of the molecule and have a high cohesive force as a polymer. (SEBS) and styrene-isobutylene-styrene block copolymer (SIBS) are preferable. You may use a commercial item as a styrene-type thermoplastic elastomer (A1). Specific examples of commercially available products include SEPTON, HYBRAR, manufactured by KURARAY CO., LTD., TUFTEC, manufactured by Asahi Kasei Corporation, and SIBSTAR, manufactured by KANEKA CORPORATION.

The weight average molecular weight of the styrene-based thermoplastic elastomer (A1) is preferably about 50,000 to 500,000, more preferably about 50,000 to 300,000, and still more preferably about 50,000 to 250,000. If the weight average molecular weight of a styrene-type thermoplastic elastomer (A1) is such a range, since the cohesion force and viscoelasticity of a polymer can be compatible, it is preferable.

The styrene content in the styrene-based thermoplastic elastomer (A1) is preferably about 5% by weight to 70% by weight, more preferably about 5% by weight to 40% by weight, and more preferably about 10% by weight to 20% by weight. to be. If the styrene content in the styrene-based thermoplastic elastomer (A1) is within this range, it is preferable because the viscoelasticity of the soft segment can be secured while maintaining the cohesion force by the styrene site.

The isobutylene-based polymer (A2) includes isobutylene as a constituent monomer, and a weight average molecular weight (Mw) is preferably 500,000 or more. The isobutylene polymer (A2) may be a homopolymer of isobutylene (polyisobutylene, PIB), or a copolymer having isobutylene as the main monomer (i.e., isobutylene in a proportion exceeding 50 mol%). Copolymerized copolymer). Examples of such copolymers include copolymers of isobutylene and normal butylene, copolymers of isobutylene and isoprene (e.g., regular butyl rubber, chlorinated butyl rubber, butyl bromide, partially crosslinked butyl rubber, etc.). Butyl rubbers), vulcanized substances and modified substances (for example, those modified with functional groups such as hydroxyl, carboxyl, amino and epoxy groups). Among these, polyisobutylene (PIB) is preferable from the point which does not contain a double bond in a main chain, and is excellent in weatherability. You may use a commercial item as an isobutylene-type polymer (A2). As a specific example of a commercial item, OPPANOL by BASF Ltd. is mentioned.

The weight average molecular weight (Mw) of the isobutylene polymer (A2) is preferably 500,000 or more, more preferably 600,000 or more, and still more preferably 700,000 or more. The upper limit of the weight average molecular weight (Mw) is preferably 5 million or less, more preferably 3 million or less, and still more preferably 2 million or less. By making the weight average molecular weight of an isobutylene-type polymer (A2) 500,000 or more, it can be set as the adhesive composition which is more excellent in durability at the time of high temperature storage.

The content of the rubber polymer (A) in the pressure-sensitive adhesive (adhesive composition) is preferably 30% by weight or more, more preferably 40% by weight or more, and even more preferably 50% by weight or more in the total solids of the pressure-sensitive adhesive composition. Especially preferably, it is 60 weight% or more. Preferably the upper limit of content of a rubber type polymer is 95 weight% or less, More preferably, it is 90 weight% or less.

In a rubber adhesive, you may use combining the said rubber type polymer (A) and another rubber type polymer. Specific examples of other rubber polymers include butyl rubber (IIR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), EPR (binary ethylene-propylene rubber), EPT (ternary ethylene-propylene rubber), acrylic rubber Urethane rubbers, polyurethane-based thermoplastic elastomers; Polyester-based thermoplastic elastomers; Blend-based thermoplastic elastomers such as polymer blends of polypropylene and EPT (tertiary ethylene-propylene rubber). The compounding quantity of another rubber type polymer becomes like this. Preferably it is about 10 weight part or less with respect to 100 weight part of said rubber type polymers (A).

The acrylic polymer of the acrylic pressure-sensitive adhesive (adhesive composition) typically contains alkyl (meth) acrylate as a main component, and an aromatic ring-containing (meth) acrylate, an amide group-containing monomer, a carboxyl group-containing monomer, and a copolymer component according to the purpose. And / or may contain a hydroxyl group-containing monomer. In this specification, "(meth) acrylate" means an acrylate and / or a methacrylate. As alkyl (meth) acrylate, the C1-C18 thing of a linear or branched alkyl group can be illustrated. Aromatic ring containing (meth) acrylate is a compound which contains an aromatic ring structure in the structure, and contains a (meth) acryloyl group. As an aromatic ring, a benzene ring, a naphthalene ring, or a biphenyl ring is mentioned. Aromatic ring containing (meth) acrylate can satisfy durability (especially durability with respect to a transparent conductive layer), and can improve the display unevenness by the picking of a peripheral part. An amide group containing monomer is a compound which contains an amide group in the structure, and also contains polymerizable unsaturated double bonds, such as a (meth) acryloyl group and a vinyl group. A carboxyl group-containing monomer is a compound which contains a carboxyl group in the structure, and also contains polymerizable unsaturated double bonds, such as a (meth) acryloyl group and a vinyl group. A hydroxyl group containing monomer is a compound which contains a hydroxyl group in the structure, and also contains polymerizable unsaturated double bonds, such as a (meth) acryloyl group and a vinyl group. The detailed description of an acrylic adhesive is described, for example in Unexamined-Japanese-Patent No. 2015-199942, The description of the said publication is integrated in this specification as a reference.

Arbitrary suitable resin can be used as resin which comprises a resin film when a matrix is a resin film. Specifically, the resin may be a thermoplastic resin, a thermosetting resin, or an active energy ray curable resin. Examples of the active energy ray curable resins include electron beam curable resins, ultraviolet curable resins, and visible ray curable resins. Specific examples of the resin include epoxy, (meth) acrylate (for example, methyl methacrylate and butyl acrylate), norbornene, polyethylene, poly (vinyl butyral), poly (vinylacetate), polyurea, polyurethane, Aminosilicone (AMS), polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxane, silicon fluoride, vinyl and hydride substituted silicones, styrene-based polymers (e.g. polystyrene , Amino polystyrene (APS), poly (acrylonitrile ethylene styrene) (AES)), a polymer crosslinked with a bifunctional monomer (e.g. divinylbenzene), a polyester polymer (e.g. polyethylene terephthalate) Cellulose polymers (e.g., triacetyl cellulose), vinyl chloride polymers, amide polymers, imide polymers, vinyl alcohol polymers, epoxy polymers, silicone polymers, An acryl urethane type polymer is mentioned. These may be used independently and may be used in combination (for example, a blend and copolymerization). After forming a film | membrane, these resin may perform the process of extending | stretching, heating, and pressurization. Preferably it is thermosetting resin or ultraviolet curable resin, More preferably, it is thermosetting resin. It is because it can apply suitably when manufacturing the optical member of this invention by a roll-to-roll.

B. Image Display

The image display device of the present invention includes an image display panel and the circular polarizing plate. As an image display panel, a liquid crystal display panel, an organic electroluminescent panel, etc. are mentioned, for example. The circular polarizing plate is disposed such that the colored layer is on the image display panel side and the polarizer is on the viewing side.

As the image display element, an image display element having a high reflectance (for example, an image display element including a member made of a metal, a member containing a metal, etc., and having a high reflectance) is suitably used. Since the circularly polarizing plate of the present invention has excellent antireflection characteristics and color adjustment functions, the influence of external light reflection can be effectively reduced even with an image display device having an image display element having a high reflectance. The visible light reflectance of the image display element with high reflectance is 15% or more, for example, Preferably it is 20%-99%.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, the measuring method of each characteristic is as follows.

[evaluation]

(1) Haze value of colored layer, adhesive layer

About the haze of a colored layer or an adhesive layer, it measured using the haze meter (made by MURAKAMI COLOR RESEARCH LABORATORY, brand name "HN-150") by the method determined by JIS 7136.

(2) polarization degree of laminate x

The polarization degree P of the laminated body x comprised from the polarizer and colored layer which comprise a circularly-polarizing plate in each Example and a comparative example was measured with the following method.

Using an ultraviolet visible spectrophotometer (manufactured by JASCO Corporation, product name "V7000 series"), the single layer transmittance (Ts), parallel transmittance (Tp), and orthogonal transmittance (Tc) of the laminate x were measured and obtained by the following equation.

Polarization degree (P) (%) = {(Tp-Tc) / (Tp + Tc)} ^1/2 × 100

In addition, the measurement of parallel transmittance | permeability Tp and orthogonal transmittance | permeability Tc was performed by making polarization inject from the colored layer side of the laminated body x. In addition, said Ts, Tp, and Tc are Y values measured with the 2-degree field of view (C light source) of JIS Z 8701, and corrected visibility.

(3) Anti-reflection ability of circular polarizer

The colored layer side of a circularly polarizing plate was bonded to the reflecting plate (Toray ADVANCED FILM Co., Ltd. brand name "CERAPEEL DMS-X42", total light reflectance: 86%), and the sample for evaluation was produced. About this evaluation sample, total light reflectance was measured using CM2600-d (made by KONICA MINOLTA, INC.).

(4) reflective color

About the evaluation sample produced in said (3), the reflection color (L * a * b * colorimeter) was measured using CM2600-d (made by KONICA MINOLTA, INC.).

Example 1

(i) Preparation of phase difference layer (λ / 4 plate)

The polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene (BHEPF), isosorbide (ISB), diethylene glycol (DEG), diphenylcarbonate (DPC), and magnesium acetate tetrahydrate It injected | poured so that it might become BHEPF / ISB / DEG / DPC / magnesium acetate = 0.348 / 0.490 / 0.162 / 1.005 / 1.00 * 10 <^-5> by molar ratio. After sufficiently nitrogen-substituting the inside of the reactor (oxygen concentration of 0.0005 to 0.001 vol%), heating was carried out with the fruit, and stirring was started when the internal temperature reached 100 ° C. 40 minutes after the start of the temperature increase, the internal temperature was reached at 220 ° C., the pressure was controlled while maintaining the temperature, and the pressure was set to 13.3 kPa at 90 minutes after reaching 220 ° C. The phenol vapors produced by-products together with the polymerization reaction were led to a reflux condenser at 100 ° C. to return the monomer components contained in the phenol vapors to the reactor, and the phenol vapors not condensed were led to a condenser at 45 ° C. and recovered.

Nitrogen was introduced into the first reactor and once back to atmospheric pressure, the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Next, the temperature increase and pressure reduction in a 2nd reactor were started, and it was internal temperature 240 degreeC, and the pressure of 0.2 kPa in 50 minutes. Thereafter, the polymerization was carried out until a predetermined stirring power was achieved. When the predetermined power was reached, nitrogen was introduced into the reactor and back-pressured, the reaction liquid was taken out in the form of strands, and pelletized with a rotary cutter to obtain a copolymer composition of BHEPF / ISB / DEG = 34.8 / 49.0 / 16.2 [mol%]. Polycarbonate resin was obtained. The reduced viscosity of this polycarbonate resin was 0.430 dL / g and the glass transition temperature was 128 degreeC.

The obtained polycarbonate resin (10 kg) was dissolved in methylene chloride (73 kg) to prepare a coating liquid. Subsequently, the said coating liquid is apply | coated directly on a shrinkable film (a longitudinally uniaxially stretched polypropylene film, the brand name "NOBLEN" made by TOKYO PRINTING INK MFG.CO., LTD.), And the coating film is dried at 30 degreeC for 5 minutes. It dried at 80 degreeC for 5 minutes, and formed the laminated body of shrinkable film / birefringence layer. The retardation film A was formed on the shrinkable film by extending | stretching the obtained laminated body using the simultaneous biaxial stretching machine and extending | stretching 1.3 times in shrinkage ratio 0.80 and TD direction in MD direction at extending | stretching temperature 155 degreeC. Next, the retardation film was peeled off from the shrinkable film. The thickness of retardation film A was 60.0 micrometers, Re (550) = 140 nm, Nz = 0.5, Re (450) / Re (550) = 0.89. This retardation film A was called retardation layer ((lambda) / 4 board).

(ii) fabrication of polarizer

A long roll of a polyvinyl alcohol (PVA) -based resin film (manufactured by KURARAY CO., LTD., Product name "PE3000") having a thickness of 30 µm was uniaxially swelled at the same time while being uniaxially stretched in the longitudinal direction so as to be 5.9 times in the longitudinal direction by a roll stretching machine. , Dyeing, crosslinking, and washing treatment were performed, and finally, a drying treatment was performed to produce a polarizer having a thickness of 12 μm.

Specifically, the swelling treatment was stretched 2.2 times while treating with pure water at 20 ° C. Subsequently, the dyeing treatment was elongated 1.4 times while treating in a 30 ° C. aqueous solution in which the weight ratio of iodine and potassium iodide in which the iodine concentration was adjusted was 45.0% so that the single transmittance of the polarizer obtained was 45.0%. In addition, the crosslinking process employ | adopted the 2nd step crosslinking process, and the 1st step crosslinking process extended | stretched 1.2 times, treating in 40 degreeC boric acid and the potassium iodide aqueous solution. The boric acid content of the aqueous solution of the crosslinking process of the 1st step was 5.0 weight%, and potassium iodide content was 3.0 weight%. The crosslinking treatment of the second stage was stretched 1.6 times while treating in an aqueous solution in which boric acid and potassium iodide were dissolved at 65 ° C. The boric acid content of the aqueous solution of the crosslinking process of the 2nd step was 4.3 weight%, and potassium iodide content was 5.0 weight%. In addition, the washing | cleaning process was processed by the 20 degreeC potassium iodide aqueous solution. The potassium iodide content of the aqueous solution of the washing process was 2.6 weight%. Finally, the drying treatment was dried at 70 ° C. for 5 minutes to obtain a polarizer.

(iii) Preparation of Polarizing Plate A

Roll to HC-TAC film (thickness: 32 micrometers, corresponding to a protective film) having a hard coat (HC) layer formed on one side of the polarizer by a hard coat treatment on one side of the TAC film via a polyvinyl alcohol adhesive on one side of the polarizer. It bonded by the roll and obtained the elongate polarizing plate A which has a structure of a protective film / polarizer.

(iv) Preparation of Polarizing Plate A with Retardation Layer

The polarizing plate and the retardation layer obtained above were cut to a predetermined size, and the retardation layer having the constitution of a protective film / polarizer / retardation layer (λ / 4 plate) was attached by bonding the polarizer surface and the retardation layer of the polarizing plate through an acrylic adhesive. A polarizing plate was obtained. In addition, cutting of the retardation layer was performed so that the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer was 45 ° when the polarizing plate and the retardation layer were bonded together.

(v) formation of colored layer

0.3 part by weight of a radical generator (benzoyl peroxide, manufactured by NOF Corporation, trade name "NYPER BMT") with respect to 100 parts by weight of an acrylic polymer formed by copolymerizing n-butyl acrylate and a hydroxyl group-containing monomer, an isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, 1 part by weight of a trade name "CORONATE L"), 0.25 parts by weight of a pigment (manufactured by Yamamoto Chemicals, Inc., a brand name "PD-320"), and a phenolic antioxidant (BASF Japan, Ltd., trade name "IRGANOX1010") The pigment | dye containing adhesive which consists of 0.2 weight part was produced. The adhesive was applied to a thickness of 20 μm with an applicator on a PET substrate (manufactured by Mitsubishi Plastics, Inc., trade name “MRF38CK”), which was easily peeled off, and dried at 155 ° C. for 2 minutes, and then the pressure-sensitive adhesive sample was applied. It pulled out and bonded the said adhesive surface to the phase difference layer side of the polarizing plate with a phase difference layer, and formed the colored layer (absorption maximum wavelength: 595 nm).

As described above, a circularly polarizing plate including a protective film, a polarizer, a retardation layer (λ / 4 plate), and a colored layer was obtained. The obtained circular polarizing plate was provided for the said evaluation (1)-(3). The results are shown in Table 1.

Example 2

(i) Preparation of antireflection film

As a base material, the triacetyl cellulose (TAC) film with a hard coat (refractive index: 1.53) was used. On the other hand, the coating liquid (medium refractive index layer) which diluted the resin composition (made by JSR Corporation, brand name "OPSTAR KZ series") containing 62% of zirconium oxide particles (average particle diameter 40nm, refractive index 2.19) by 3% with MIBK. The composition for formation) was prepared. The coating liquid was applied onto the substrate using a bar coater, and dried at 60 ° C. for 1 minute, and then irradiated with ultraviolet light having a accumulated light amount of 300 mJ to form a medium refractive index layer (refractive index: 1.68, thickness: 100 nm). Next, a high refractive index layer (refractive index: 2.33, thickness: 12 nm) was formed on the medium refractive index layer by sputtering Nb2O5. Further, by sputtering SiO 2, a low refractive index layer (refractive index: 1.47, thickness: 110 nm) was formed on the high refractive index layer. In this way, an antireflection film was produced.

(ii) Preparation of Polarizing Plate B

A polarizer was produced in the same manner as in Example 1, and the antireflection film was bonded to one side of the TAC film through a polyvinyl alcohol adhesive on one side of the polarizer to obtain a polarizing plate B having the configuration of the antireflection treatment layer / polarizer.

(iii) fabrication of circular polarizer

A circularly polarizing plate was produced in the same manner as in Example 1 except that the polarizing plate B was used instead of the polarizing plate A. The obtained circular polarizing plate was provided for the said evaluation (1)-(3). The results are shown in Table 1.

Comparative Example 1

A circularly polarizing plate was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive forming the colored layer did not contain a dye (that is, the pressure-sensitive adhesive layer was formed instead of the colored layer). The obtained circular polarizing plate was provided for the said evaluation (1)-(3). The results are shown in Table 1.

Example 3

(i) Preparation of phase difference layer (λ / 4 plate)

The retardation film B was obtained by diagonally stretching the cycloolefin resin film (The product made by Zeon Corporation, brand name "ZEONOR ZF-14 film" at the extending | stretching angle 45 degree using a tenter drawing machine. The thickness of this retardation film B is 57 nm, Re ( 550) = 130 nm, Nz = 1.60, and Re (450) / Re (550) = 1.03.

(ii) Preparation of Polarizing Plate B with Retardation Layer

A polarizing plate B with a retardation layer was produced in the same manner as in Example 1 except that the retardation film B was replaced with the retardation film A as the retardation layer (λ / 4 plate).

(iii) formation of colored layer

Instead of the polarizing plate A with a retardation layer, the polarizing plate B with a retardation layer was used, and instead of 0.25 weight part of dyes (made by Yamamoto Chemicals, Inc., brand name "PD-320"), a dye (made by Yamamoto Chemicals, Inc. A colored layer (absorption maximum wavelength: 493 nm) was formed like Example 1 except having used 0.5 weight part of brand names "PD-1023", and a circularly polarizing plate (protective film / polarizer / retardation layer ((lambda / 4 plate)) / Colored layer) was obtained. The obtained circular polarizing plate was provided for the said evaluation (1)-(4). The results are shown in Table 2. In addition, when the reflection color was measured, it was confirmed by the naked eye, and it was confirmed that the appearance was excellent in the anti-reflection ability and the reflection color.

Comparative Example 2

A circularly polarizing plate was obtained in the same manner as in Example 3 except that the pressure-sensitive adhesive forming the colored layer did not contain a dye (that is, the pressure-sensitive adhesive layer was formed instead of the colored layer). The obtained circular polarizing plate was provided for the said evaluation (1)-(4). The results are shown in Table 2. In addition, when the reflection color was measured visually, it was confirmed that the appearance was bluish and the reflection color was not good.

Example 4

(i) Preparation of Polarizing Plate C with Retardation Layer

The lambda / 2 plate, the lambda / 4 plate, and the polarizing plate were produced by the method described in the example of Japanese Patent No. 4849454.

This λ / 4 plate is used as the first retardation layer, and the λ / 2 plate is used as the second retardation layer in the order of the polarizing plate, the second retardation layer (λ / 2 plate), and the first retardation layer (λ / 4 plate). A polarizing plate C (protective film / polarizer / protective film / second retardation layer (λ / 2 plate) / first retardation layer (λ / 4 plate)) having a retardation layer attached thereto was prepared by bonding through an acrylic adhesive.

The first retardation layer (λ / 4 plate) had a refractive index distribution of nx> ny> nz, had a thickness of 39 µm, and Re (550) = 120 nm, Nz coefficient = 1.6. The second retardation layer (λ / 2 plate) had a thickness of 2.4 µm and Re (550) = 240 nm.

(ii) formation of colored layer

Instead of polarizing plate A with retardation layer, polarizing plate C with retardation layer was used, and instead of 0.25 parts by weight of pigment (manufactured by Yamamoto Chemicals, Inc., trade name "PD-320"), a dye (manufactured by MIKUNI COLOR LTD., A circularly polarizing plate (protective film / polarizer / protective film / second retardation layer (λ / 2 plate) / first retardation layer (λ / 4) was used in the same manner as in Example 1 except that 0.5 parts by weight of the product name was used. Plate) / colored layer) was obtained. The obtained circular polarizing plate was provided for the said evaluation (1)-(3). The results are shown in Table 3.

Comparative Example 3

A circularly polarizing plate was prepared in the same manner as in Example 4 except that 0.5 parts by weight of the pigment (MHI Black # PD-044M, manufactured by MIKUNI COLOR LTD.) Was used instead of 0.5 parts by weight of the pigment (manufactured by MIKUNI COLOR LTD.). Got it. The obtained circular polarizing plate was provided for the said evaluation (1)-(3). The results are shown in Table 3.

[Comparative Example 4]

A circularly polarizing plate was obtained in the same manner as in Example 4 except that the pressure-sensitive adhesive forming the colored layer did not contain a dye (that is, the pressure-sensitive adhesive layer was formed instead of the colored layer). The obtained circular polarizing plate was provided for the said evaluation (1)-(3). The results are shown in Table 3.

As is apparent from the comparison between Example 1 and Comparative Example 1, the comparison between Example 3 and Comparative Example 2, and the comparison between Example 4 and Comparative Example 4, the circular polarizing plate of the present invention has excellent anti-reflection characteristics by having a colored layer. Do. In addition, as is apparent from the comparison between Example 3 and Comparative Example 2, the circular polarizing plate of the present invention can emit light having a neutral color by adjusting the reflection color by providing a colored layer. In addition, when the polarization degree of the laminated body x which consists of a polarizer and a colored layer is small, as is clear from the comparison of Example 4 and the comparative example 3, the said effect of this invention is not acquired.

(Industrial availability)

The circular polarizing plate of this invention is used suitably for image display apparatuses, such as a liquid crystal display device.

10: polarizer 20a: retardation layer
30: colored layer 100: circularly polarizing plate

Claims (11)

The polarizer, the phase difference layer 20a which functions as a (lambda) / 4 plate, and a colored layer are provided in this order,
The angle between the absorption axis of the polarizer and the slow axis of the retardation layer 20a is 35 ° to 55 °,
The circularly-polarizing plate whose polarization degree of the laminated body which consists of the said polarizer and the said colored layer is 99.9% or more. The method of claim 1,
A retardation layer 20b functioning as a λ / 2 plate is further provided between the polarizer and the retardation layer 20a functioning as the λ / 4 plate,
The angle between the absorption axis of the polarizer and the retardation layer 20a is 65 ° to 85 °,
The circular polarizing plate of the angle between the absorption axis of the polarizer and the retardation layer (20b) is 10 ° ~ 20 °. The method according to claim 1 or 2,
Circular polarizing plate wherein the colored layer selectively absorbs light in a specific wavelength range. The method of claim 3, wherein
The circular polarizing plate, wherein the colored layer has an absorption maximum wavelength in a wavelength range of 440 nm to 510 nm. The method of claim 3, wherein
The circular polarizing plate, wherein the colored layer has an absorption maximum wavelength in a wavelength range of 560 nm to 610 nm. The method according to any one of claims 1 to 5,
The circularly polarizing plate whose haze value of the said colored layer is 15% or less. The method according to any one of claims 1 to 6,
The circularly polarizing plate of which the polarization degree of the said polarizer is 99.9% or more. The method according to any one of claims 1 to 7,
Re (450) / Re (550) of the phase difference layer 20a which functions as said (lambda) / 4 board is 0.5 or more and less than 1.0,
The circularly polarizing plate of which the Nz coefficient of the retardation layer (20a) is 0.3 ~ 0.7. The method according to any one of claims 1 to 8,
Circularly polarizing plate having a low reflection treatment layer on the outermost surface. The image display apparatus provided with the circularly-polarizing plate of any one of Claims 1-9. The method of claim 10,
Further comprising an image display panel,
And an visible light reflectance of the image display panel is 20% or more.

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