KR20190039599A - Optical laminate and image display device - Google Patents

Abstract

(EN) Disclosed is an optical laminate in which cracking of a conductive layer under high temperature and high humidity is suppressed. The optical laminate of the present invention has a polarizer, a polarizing plate including a protective layer on at least one side of the polarizer, a first retardation layer, a second retardation layer, and a conductive layer in this order. In this optical laminate, a pressure-sensitive adhesive layer for bonding the second retardation layer and the conductive layer is provided. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer includes a pressure-sensitive adhesive polymer. The amount of the acid component in the total monomer component constituting the pressure- is less than%, the storage elastic modulus at 85 ℃ of the pressure-sensitive adhesive is ^{1.0 × 10 4 Pa~7.0 × 10 4} Pa.

Description

Optical laminate and image display device

The present invention relates to an optical laminate and an image display apparatus using the same.

Recently, with the spread of thin type displays, a display (organic EL display device) on which an organic EL panel is mounted has been proposed. Since the organic EL panel has a highly reflective metal layer, it tends to cause problems such as reflection of external light and background reflection. Thus, it is known to prevent such problems by providing a circular polarizer on the viewing side. On the other hand, there is an increasing demand for a so-called inner touch panel type input display device in which a touch sensor is incorporated between a display cell (e.g., an organic EL cell) and a polarizing plate. In the input display device having such a configuration, since the distance between the image display cell and the touch sensor is close to each other, it is possible to give a natural input operation feeling to the user.

In the polarizing plate (or the circularly polarizing plate) for the inner touch panel type input display device, the integration of the polarizing plate (or circularly polarizing plate) and the conductive film for the touch sensor is considered from the viewpoints of thinning, prevention of deviation in quality, have. However, the polarizing plate in which the conductive film for a touch sensor is integrated has a problem that cracks are easily generated in the conductive layer of the conductive film under high temperature and high humidity.

Japanese Laid-Open Patent Publication No. 2003-311239 Japanese Laid-Open Patent Publication No. 2002-372622 Japanese Patent Publication No. 3325560 Japanese Patent Application Laid-Open No. 2003-036143

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and its main object is to provide an optical laminate in which cracking of a conductive layer is suppressed under high temperature and high humidity.

The optical laminate of the present invention has a polarizer, a polarizing plate including a protective layer on at least one side of the polarizer, a first retardation layer, a second retardation layer, and a conductive layer in this order. In this optical laminate, an adhesive layer for bonding the second retardation layer and the conductive layer is provided, and the adhesive constituting the pressure sensitive adhesive layer includes a pressure sensitive adhesive polymer. in an amount less than 4 wt%, the storage elastic modulus at 85 ℃ of the adhesive is ^{1.0 × 10 4 Pa~7.0 × 10 4} Pa.

In one embodiment, the angle formed between the absorption axis of the polarizer and the phase axis of the first retardation layer is 10 ° to 20 °, and the angle between the absorption axis and the slow axis of the second retardation layer The angle is between 65 ° and 85 °.

In one embodiment, the first retardation layer and the second retardation layer are composed of a cyclic olefin based resin film. In this case, the dimensional change rate of the second retardation layer is, for example, 1% or less.

In another embodiment, the first retardation layer and the second retardation layer are oriented solidified layers of a liquid crystal compound. In this case, the dimensional change ratio of the laminate of the polarizing plate, the first retardation layer and the second retardation layer is, for example, 1% or less.

According to another aspect of the present invention, an image display apparatus is provided. This image display apparatus is provided with the above optical laminate.

According to the present invention, in the optical laminate having the polarizing plate, the two retardation layers and the conductive layer for the touch sensor, the adhesive layer constituting the adhesive layer for bonding the retardation layer and the conductive layer to the whole of the adhesive polymer constituting the adhesive layer It is possible to optimize the acid component in the monomer component to a predetermined amount or less and to optimize the storage elastic modulus of the pressure-sensitive adhesive to a predetermined range, whereby cracking of the conductive layer under high temperature and high humidity can be remarkably suppressed. As a result, an optical laminate having extremely excellent durability can be realized.

1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention.

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

(Definition of terms and symbols)

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

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

'nx' is a refractive index in a direction perpendicular to the slow axis in the plane (that is, the fast phase axis direction), and 'nx' is a refractive index in a direction in which the in- 'nz' is the refractive index in the thickness direction.

(2) In-plane retardation (Re)

'Re (?)' Is an in-plane retardation measured with light having a wavelength of? Nm at 23 占 폚. For example, 'Re (550)' is an in-plane retardation measured at a wavelength of 550 nm at 23 ° C. Re (λ) can be obtained by the formula: Re (λ) = (nx-ny) × d where d (nm) is the thickness of the layer (film).

(3) The retardation in the thickness direction (Rth)

'Rth (?)' Is a retardation in the thickness direction measured by light having a wavelength of? Nm at 23 占 폚. For example, 'Rth (550)' is the retardation in the thickness direction measured by light having a wavelength of 550 nm at 23 ° C. Rth (?) Can be obtained by the formula: Rth (?) = (Nx-nz) xd where d (nm) is the thickness of the layer (film).

(4) Nz coefficient

The Nz coefficient can be obtained by Nz = Rth / Re.

A. Overall construction of optical laminate

1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The optical laminate 100 of the present embodiment has a polarizing plate 10, a first retardation layer 20, a second retardation layer 30, and a conductive layer 50 in this order. In the optical laminate 100, a pressure-sensitive adhesive layer 40 for bonding the second retardation layer 30 and the conductive layer 50 is provided. The polarizing plate 10 includes a first protective layer 12 disposed on one side of the polarizer 11 and the polarizer 11 and a second protective layer 13 disposed on the other side of the polarizer 11 . One of the first protective layer 12 and the second protective layer 13 may be omitted depending on the purpose. For example, when the first retardation layer 20 can also function as a protective layer of the polarizer 11, the second protective layer 13 may be omitted. Practically, the conductive layer may be provided as a conductive layer with a base material having the conductive layer 51 and the base material 52. Therefore, the optical laminate 100 may further have the base material 52 of the conductive layer 51. [ Also, for ease of viewing, the thickness ratio of each layer in the drawing is different from the actual.

In the embodiment of the present invention, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 40 includes a pressure-sensitive adhesive polymer, and the amount of the acid component in the total monomer component constituting the pressure-sensitive adhesive polymer is less than 4% by weight, preferably 0 to 3% %, More preferably 0 to 2 wt%, still more preferably 0 to 1 wt%, and particularly preferably substantially zero. If the amount of the acid component is in this range, the influence of the acid component on the conductive layer becomes negligibly small, and as a result, occurrence of cracks in the conductive layer under high temperature and high humidity can be remarkably suppressed. In this specification, "substantially zero" means not actively mixing, except when it is inevitably incorporated. Further, the storage elastic modulus at 85 ℃ of the pressure-sensitive adhesive was ^{1.0 × 10 4 Pa~7.0 × 10 4} Pa , preferably ^{2.0 × 10 4 Pa~6.0 × 10 4} Pa , and more preferably from 3.0 × 10 ⁴ Pa~5.5 × 10 ⁴ Pa. The storage elastic modulus can be measured in accordance with JIS K 7244.

In one embodiment, the first retardation layer 20 and the second retardation layer 30 are each made of a resin film. In another embodiment, the first retardation layer 20 and the second retardation layer 30 may be an oriented solidified layer of a liquid crystal compound, respectively. In addition, the resin film is described in detail in C-2 and D-2, and the oriented solidified layer of the liquid crystal compound is described in detail in C-3 and D-3 respectively.

Other than the adhesion between the second retardation layer 30 and the conductive layer 50, the respective layers constituting the optical laminate may be laminated via any suitable adhesive layer (adhesive layer or pressure-sensitive adhesive layer: not shown) That is, without using an adhesive layer).

 The dimensional change ratio of the optical laminate is preferably 1% or less, and more preferably 0.95% or less. The dimensional change ratio of the optical laminate is preferably as small as possible. The lower limit of the rate of dimensional change of the optical laminate is, for example, 0.01%. When the dimensional change ratio of the optical laminate is in this range, generation of cracks in the conductive layer under high temperature and high humidity can be remarkably suppressed. In the present specification, the dimensional change rate refers to the rate of dimensional change when the sample is placed under an environment of a temperature of 85 캜 and a relative humidity of 85% for 240 hours.

The total thickness of the optical laminate is preferably 220 占 퐉 or less, and more preferably 80 占 퐉 to 190 占 퐉. When the first retardation layer 20 and the second retardation layer 30 are an oriented solidified layer of a liquid crystal compound, the total thickness of the optical laminate is preferably 175 탆 or less, and more preferably 80 탆 to 140 탆 .

The optical laminate may be elongated (for example, in the form of a roll) or may be in a sheet form.

Hereinafter, each layer constituting the optical laminate, the optical film and the pressure-sensitive adhesive will be described in more detail.

B. Polarizer

B-1. Polarizer

As the polarizer 11, any appropriate polarizer may be employed. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

Specific examples of the polarizer composed of the single-layer resin film include a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, and an ethylene / vinyl acetate copolymer system partially saponified film, A dyeing treatment and a stretching treatment using a dichroic material; A polyene-based oriented film such as a dehydrated product of PVA or a dehydrochlorinated product of polyvinyl chloride. Preferably, a polarizer obtained by dying a PVA-based film with iodine and uniaxially stretching is used because it has excellent optical properties.

The dyeing with iodine is carried out, for example, by immersing the PVA-based film in an aqueous iodine solution. The draw ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after the dyeing treatment, or may be performed while dyeing. Further, it may be dyed after stretching. The PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, and the like, if necessary. For example, the PVA film is dipped in water and washed with water before dyeing, so that it is possible not only to clean the contamination of the surface of the PVA film and the antiblocking agent but also to prevent the dyeing unevenness and the like by expanding the PVA film.

Specific examples of the polarizer obtained by using the laminate include a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA resin layer formed on the resin substrate And a polarizer obtained by using a laminate. A polarizer obtained by using a laminate of a resin substrate and a PVA resin layer formed on the resin substrate is obtained by, for example, applying a PVA resin solution to a resin substrate and drying the PVA resin layer to form a PVA resin layer on the resin substrate, To obtain a laminate of a substrate and a PVA-based resin layer; And stretching and dyeing the laminate to prepare a PVA-based resin layer as a polarizer. In the present embodiment, the stretching typically includes immersing the laminate in an aqueous solution of boric acid and stretching. Further, the stretching may further include, if necessary, air-stretching the laminate at a high temperature (for example, 95 DEG C or higher) before stretching in an aqueous solution of boric acid. The obtained resin substrate / polarizer laminate may be used as is (that is, the resin substrate may be used as a protective layer of the polarizer), the resin substrate may be peeled off from the laminate of the resin substrate / polarizer, Any suitable protective layer may be used by being laminated. Details of the method for producing such a polarizer are described, for example, in Japanese Laid-Open Patent Publication No. 2012-73580. This publication is incorporated herein by reference in its entirety.

The thickness of the polarizer is preferably 18 占 퐉 or less, more preferably 1 占 퐉 to 12 占 퐉, still more preferably 3 占 퐉 to 12 占 퐉, and particularly preferably 5 占 퐉 to 12 占 퐉.

The content of boric acid in the polarizer is preferably 18% by weight or more, and more preferably 18% by weight to 25% by weight. When the content of boric acid in the polarizer is in this range, it is possible to maintain the ease of curl adjustment at the time of conjugation favorably due to the synergistic effect with the iodine content to be described later, Durability can be improved. The boric acid content can be calculated, for example, from the neutralization method by the amount of boric acid contained in the polarizer per unit weight by using the following formula (1).

[Formula 1]

The iodine content of the polarizer is preferably 2.1% by weight or more, and more preferably 2.1% by weight to 3.5% by weight. When the content of iodine in the polarizer is in this range, it is possible to maintain the ease of curl adjustment at the time of bonding by satisfactory effect with the boric acid content as described above, and to improve the appearance durability Can be improved. In the present specification, the term "iodine content" means the amount of all iodine contained in the polarizer (PVA resin film). More specifically, the iodine in the polarizer is present in the form of iodine ion (I ^- ), iodine molecule (I ₂ ), polydiode ion (I ₃ ^- , I ₅ ^- ), And the amount of iodine including all of these forms. The iodine content can be calculated, for example, by the calibration curve method of fluorescence X-ray analysis. Also, the poly iodide exists in the form of a PVA-iodine complex in the polarizer. By forming such a complex, absorption dichroism can be expressed in the wavelength range of visible light. Specifically, the complex (PVA · I ₃ ^- ) between PVA and triiodide ion has an absorption peak near 470 nm, and the complex (PVA · I ₅ ^- ) between PVA and 5-iodide ion is absorbed Peak. As a result, the polyiodide ion can absorb light in a wide range of visible light depending on its form. On the other hand, the iodine ion (I < ^- >) has an absorption peak near 230 nm and is not substantially involved in the absorption of visible light. Therefore, the poly iodide ion existing in a complex state with PVA can mainly participate in the absorption performance of the polarizer.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The transmittance of the polarizer is in the range of 43.0% to 46.0%, preferably 44.5% to 46.0%, as described above. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more.

B-2. The first protective layer

The first protective layer 12 is formed of any suitable film that can be used as the protective layer of the polarizer. Specific examples of the material constituting the main component of the film include cellulosic resins such as triacetyl cellulose (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyether sulfone resins , Polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth) acrylic-based, and acetate-based transparent resins. Further, thermosetting resins such as (meth) acrylic resins, urethane resins, (meth) acrylic urethane resins, epoxy resins and silicon resins, and ultraviolet curing resins can also be used. Other examples include glassy polymers such as siloxane polymers. Further, a polymer film described in Japanese Patent Application Laid-Open No. 2001-343529 (WO01 / 37007) may also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a phenyl group and a substituted or unsubstituted phenyl group and / or nitrile group in the side chain can be used. And a resin composition having an alternating copolymer composed of methylmaleimide and an acrylonitrile styrene copolymer. The polymer film may be, for example, an extrusion molded article of the resin composition.

The optical laminate of the present invention is typically disposed on the viewer side of the image display apparatus, as will be described later, and the first protective layer 12 is typically disposed on the viewer side thereof. Therefore, the first protective layer 12 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and antiglare treatment, if necessary. Further, the first protective layer 12 may be provided with a treatment for improving the visibility in the case of visually observing through polarized sunglasses as required (typically, one providing a (circular) polarizing function or an ultra high retardation) . By performing such processing, excellent visibility can be realized even when a display screen is viewed through a polarizing lens such as polarizing sunglasses. Therefore, the optical laminate can be suitably applied also to an image display device which can be used outdoors.

Any suitable thickness may be employed as long as the thickness of the first protective layer is within a range in which the difference between the thickness of the desired polarizing plate and the thickness of the second protective layer is obtained. The thickness of the first protective layer is, for example, 10 mu m to 50 mu m, preferably 15 mu m to 40 mu m. When the surface treatment is performed, the thickness of the first protective layer includes the thickness of the surface treatment layer.

B-3. The second protective layer

The second protective layer 13 is also formed of any suitable film that can be used as the protective layer of the polarizer. The material that becomes the main component of the film is as described in the above section B-2 with respect to the first protective layer. The second protective layer 13 is preferably optically isotropic. In the present specification, "optically isotropic" means that the in-plane retardation Re 550 is 0 nm to 10 nm and the retardation Rth (550) in the thickness direction is -10 nm to +10 nm.

The thickness of the second protective layer is, for example, 15 mu m to 35 mu m, preferably 20 mu m to 30 mu m. The difference between the thickness of the first protective layer and the thickness of the second protective layer is preferably 15 占 퐉 or less, more preferably 10 占 퐉 or less. When the difference in thickness is in this range, curling at the time of bonding can be satisfactorily suppressed. The thickness of the first protective layer and the thickness of the second protective layer may be the same, or the first protective layer may be thicker and the second protective layer may be thicker. Typically, the first protective layer is thicker than the second protective layer.

C. First retardation layer

C-1. Characteristics of the first retardation layer

The first retardation layer 20 may have any suitable optical and / or mechanical properties depending on the purpose. The first retardation layer 20 typically has a slow axis. In one embodiment, the angle formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizer 11 is preferably 10 ° to 20 °, more preferably 13 ° to 17 °, More preferably about 15 [deg.]. When the angle formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizer 11 is in this range, the in-plane retardation of the first retardation layer and the retardation of the second retardation layer are set to a predetermined range, respectively, And arranging the slow axis of the second retardation layer at a predetermined angle with respect to the absorption axis of the polarizer, it is possible to obtain an optical laminate having very excellent circularly polarized light characteristics (as a result, very excellent antireflection properties) in a wide band.

The first retardation layer preferably exhibits a refractive index characteristic of nx > ny > = nz. The in-plane retardation Re (550) of the first retardation layer is preferably 180 nm to 320 nm, more preferably 200 nm to 290 nm, still more preferably 230 nm to 280 nm. Here, 'ny = nz' includes not only cases where ny and nz are completely equal but also substantially the same case. Therefore, there may be a case where ny < nz is satisfied within a range that does not impair the effect of the present invention.

The Nz coefficient of the first retardation layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, particularly preferably 0.9 to 1.3. By satisfying this relationship, a very excellent reflection color can be achieved when the resulting optical laminate is used in an image display apparatus.

The first retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases with the wavelength of the measurement light or may exhibit a positive wavelength dispersion characteristic in which the retardation value decreases with the wavelength of the measurement light. Therefore, a flat wavelength dispersion characteristic which hardly changes is also possible. In one embodiment, the first retardation layer exhibits a flat wavelength dispersion characteristic in which the retardation value hardly changes according to the wavelength of the measurement light. In this case, 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 first retardation layer exhibiting a flat wavelength dispersion characteristic and having a predetermined in-plane retardation and a second retardation layer exhibiting a flat wavelength dispersion characteristic and having a predetermined in-plane retardation at a predetermined retard angle, Excellent antireflection characteristics can be realized.

A first retardation layer has the absolute value of photoelastic coefficient of preferably from ² × 10 ^-11 m 2 / N or less, more preferably ^{2.0 × 10 -13 m 2 /N~1.5×10 -11} m 2 / N, and more preferably it comprises a resin of ^{1.0 × 10 -12 m 2 /N~1.2×10 -11} m 2 / N. When the absolute value of the photoelastic coefficient is within this range, the retardation change hardly occurs when shrinkage stress is generated at the time of heating. The heat unevenness of the resulting image display device can be well prevented.

C-2. A first retardation layer made of a resin film

When the first retardation layer is made of a resin film, its thickness is preferably 60 占 퐉 or less, and preferably 30 占 퐉 to 50 占 퐉. If the thickness of the first retardation layer is within this range, a desired in-plane retardation can be obtained.

The first retardation layer 20 may be composed of any suitable resin film that can satisfy the characteristics described in the above section C-1. Representative examples of such a resin include a resin such as a cyclic olefin resin, a polycarbonate resin, a cellulose resin, a polyester resin, a polyvinyl alcohol resin, a polyamide resin, a polyimide resin, a polyether resin, a polystyrene resin , And acrylic resins. When the first retardation layer is composed of a resin film exhibiting flat wavelength characteristics, a cyclic olefin-based resin can be preferably used.

The cyclic olefin resin is a generic name of a resin that polymerizes a cyclic olefin as a polymerization unit and is disclosed in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137 And the resins described therein. Specific examples include ring-opened (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers (typically random copolymers) of cyclic olefins and? -Olefins such as ethylene and propylene, and unsaturated carboxylic acids and their derivatives Modified graft-modified compounds and hydrides thereof. Specific examples of cyclic olefins include norbornene monomers. Examples of the norbornene monomers include norbornene and its alkyl and / or alkylidene substituents such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5- Butyl-2-norbornene, and 5-ethylidene-2-norbornene; halogen-substituted polar groups such as halogen; Dicyclopentadiene, 2,3-dihydrodicyclopentadiene and the like; Dimethanooctahydronaphthalene, its alkyl and / or alkylidene substituents and polar substituents such as halogen, 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- -1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: , 4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8, Octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl- 1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene and the like; Tetramers of cyclopentadiene such as 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-cyclopentanthracene, etc. .

In the present invention, other cycloolefins capable of ring-opening polymerization may be used in combination as long as the object of the present invention is not impaired. Specific examples of such cycloolefins include compounds having one reactive double bond such as cyclopentene, cyclooctene, and 5,6-dihydrodicyclopentadiene.

The cyclic olefin resin preferably has a number average molecular weight (Mn) measured by a gel permeation chromatography (GPC) method using a toluene solvent of preferably 25,000 to 200,000, more preferably 30,000 to 100,000, and most preferably 40,000 ~ 80,000. When the number average molecular weight is within the above range, the mechanical strength is excellent and the solubility, moldability, and flexibility operability are good.

When the cyclic olefin resin is obtained by hydrogenating a ring-opening polymer of a norbornene monomer, the hydrogenation ratio is preferably 90% or more, more preferably 95% or more, and most preferably 99% or more . With such a range, heat resistance and heat resistance are excellent.

A commercially available film may be used as the cyclic olefin based resin film. Specific examples thereof include trade name "Zeonex", "Zeonoa" manufactured by Japan Zeon Company, "Arton" manufactured by JSR Corporation, "Topaz" manufactured by TICONA, and "APEL" .

The first retardation layer 20 is obtained, for example, by stretching a film formed of the cyclic olefin based resin. As a method of forming a film from a cyclic olefin resin, any appropriate molding processing method may be employed. Specific examples include a compression molding method, a transfer molding method, an injection molding method, an extrusion molding method, a blow molding method, a powder molding method, an FRP molding method, a cast coating method (for example, a casting method), a calender molding method and a hot pressing method. Extrusion molding method or cast coating method is preferable. This is because the smoothness of the obtained film can be enhanced and favorable optical uniformity can be obtained. The molding conditions can be appropriately set according to the composition and kind of the resin to be used, the desired properties of the retardation layer, and the like. As described above, since many film products are commercially available as the cyclic olefin-based resin, the commercially available film may be directly supplied to the stretching treatment.

The thickness of the resin film (unstretched film) can be set to any appropriate value according to the desired thickness of the first retardation layer, desired optical properties, stretching conditions to be described later, and the like. Mu] m to 300 [mu] m.

The stretching may be carried out by any suitable stretching method, stretching conditions (e.g., stretching temperature, stretching magnification, stretching direction). Specifically, various drawing methods such as free-end drawing, fixed-end drawing, free-end shrinking, and fixed-end shrinking may be used alone or simultaneously or sequentially. The stretching direction can also be performed in various directions and dimensions such as the longitudinal direction, the width direction, the thickness direction, and the oblique direction. The stretching temperature is preferably from Tg-30 캜 to Tg + 60 캜, more preferably from Tg-10 캜 to Tg + 50 캜, with respect to the glass transition temperature (Tg) of the resin film.

By appropriately selecting the stretching method and stretching conditions, a retardation film having desired optical properties (for example, refractive index characteristics, in-plane retardation, and Nz coefficient) can be obtained.

In one embodiment, the retardation film is produced by uniaxially stretching or uniaxially stretching the resin film. As a specific example of the monolayer uniaxial stretching, there is a method of stretching the resin film in the width direction (transverse direction) while running in the longitudinal direction. The draw ratio is preferably 1.1 to 3.5 times.

In another embodiment, the retardation film can be produced by obliquely stretching a long-length resin film continuously in a predetermined angular direction with respect to the longitudinal direction. By employing the oblique stretching, a stretched film of elongated shape having an orientation angle (a slow axis in the direction of the angle) at a predetermined angle with respect to the longitudinal direction of the film is obtained. For example, roll-to- So that the manufacturing process can be simplified. The angle may be an angle formed by the absorption axis of the polarizer and the slow axis of the first retardation layer in the optical laminate. The angle is preferably 10 ° to 20 °, more preferably 13 ° to 17 °, and still more preferably about 15 ° as described above.

Examples of the stretching machine used for oblique stretching include a tenter stretcher capable of imparting a feed force or a pulling force or a pulling force at right and left different speeds in the transverse and / or longitudinal direction. As the tenter-like stretching machine, there are a transverse stretching machine and a simultaneous biaxial stretching machine. However, any suitable stretching machine can be used as long as the elongated-phase resin film can be continuously obliquely stretched.

By appropriately controlling the right and left velocities in the stretcher, it is possible to obtain a first retardation layer (substantially a long-axis phase retardation film) having the desired in-plane retardation and a slow axis in the desired direction.

The stretching temperature of the film may be changed depending on the desired in-plane retardation value and thickness of the first retardation layer, the type of resin used, the thickness of the film to be used, the stretching magnification, and the like. Specifically, the stretching temperature is preferably Tg-30 ° C to Tg + 30 ° C, more preferably Tg-15 ° C to Tg + 15 ° C, and most preferably Tg-10 ° C to Tg + 10 ° C. By drawing at such a temperature, a first retardation layer having suitable properties in the present invention can be obtained. Tg is the glass transition temperature of the constituent material of the film.

C-3. A first retardation layer made of an oriented solidified layer of a liquid crystal compound

The first retardation layer 20 may be an oriented solidified layer of a liquid crystal compound. The difference between nx and ny of the retardation layer obtained by using the liquid crystal compound can be made significantly larger than that of the non-liquid crystal material, so that the thickness of the first retardation layer for obtaining a desired in-plane retardation can be remarkably reduced. As a result, another thinning of the optical laminate can be realized. When the first retardation layer 20 is composed of an oriented solidified layer of a liquid crystal compound, the thickness thereof is preferably 1 m to 7 m, more preferably 1.5 m to 2.5 m. By using the liquid crystal compound, in-plane retardation equivalent to that of the resin film can be achieved with a significantly thinner thickness than the resin film.

In this specification, the term 'oriented solidified layer' refers to a layer in which a liquid crystal compound is oriented in a predetermined direction in a layer and its alignment state is fixed. The 'oriented solidified layer' is a concept including an oriented hardened layer obtained by curing a liquid crystal monomer as described later. In the present embodiment, the rod-like liquid crystal compound is typically oriented in a state in which it is aligned in the slow axis direction of the first retardation layer (homogeneous orientation). The liquid crystal compound includes, for example, a liquid crystal compound (nematic liquid crystal) in which the liquid crystal phase is a nematic phase. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal display mechanism of the liquid crystal compound may be either lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a crosslinkable monomer. This is because the alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (i.e., curing) the liquid crystal monomer. After the liquid crystal monomer is aligned, for example, when the liquid crystal monomers are polymerized or crosslinked, the alignment state can be fixed accordingly. Here, a polymer is formed by polymerization and a three-dimensional mesh structure is formed by crosslinking, which are non-liquid crystalline. Therefore, the first retardation layer formed does not cause transition to a liquid crystal phase, a glass phase, or a crystal phase due to, for example, a temperature change peculiar to the liquid crystalline compound. As a result, the first retardation layer becomes a highly stable retardation layer which is not affected by the temperature change.

The temperature range in which the liquid crystal monomer exhibits liquid crystallinity differs depending on the kind thereof. Specifically, the temperature range is preferably 40 to 120 占 폚, more preferably 50 to 100 占 폚, and most preferably 60 to 90 占 폚.

As the liquid crystal monomer, any appropriate liquid crystal monomer may be employed. Polymerizable mesogen compounds described in Japanese Patent Application Publication Nos. 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171 and GB2280445. Specific examples of such a polymerizable mesogen compound include, for example, a trade name LC242 manufactured by BASF Corporation, a trade name E7 manufactured by Merck Co., and a trade name LC-Sillicon-CC3767 manufactured by Wacker-Chem. As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferable.

The oriented solidified layer of the liquid crystal compound is obtained by subjecting the surface of a predetermined substrate to an orientation treatment, coating the surface with a coating liquid containing a liquid crystal compound, aligning the liquid crystal compound in a direction corresponding to the alignment treatment, As shown in Fig. By using such alignment treatment, the liquid crystal compound can be oriented in a predetermined direction with respect to the longitudinal direction of the elongated base material, and the retardation axis can be expressed in a predetermined direction of the resulting retardation layer. For example, a phase difference layer having a slow axis in the direction of 15 DEG with respect to the longitudinal direction can be formed on a long phase substrate. Even when it is desired that the retardation layer has a slow axis in the oblique direction, since the lamination can be performed using a roll-to-roll, the productivity of the optical laminate can be remarkably improved. In one embodiment, the substrate is any suitable resin film, and the oriented solidified layer formed on the substrate can be transferred to the surface of the polarizing plate 10. In another embodiment, the substrate may be the second protective layer 13. In this case, since the transferring step is omitted, the lamination can be performed successively from the formation of the oriented solidified layer (first retardation layer) by the roll-to-roll method, and the productivity is further improved.

As the alignment treatment, any suitable alignment treatment may be employed. Specifically, there are mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of the mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of the physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of the chemical alignment treatment include an oblique deposition method and a photo alignment treatment. The processing conditions for the various alignment treatments may be any suitable conditions depending on the purpose.

The orientation of the liquid crystal compound is carried out by treating the liquid crystal compound at a temperature which indicates the liquid crystal phase depending on the kind of the liquid crystal compound. By performing such a temperature treatment, the liquid crystal compound takes a liquid crystal state, and the liquid crystal compound is oriented in accordance with the orientation treatment direction of the substrate surface.

The fixation of the alignment state is carried out in one embodiment by cooling the liquid crystal compound oriented as described above. In the case where the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the fixing of the alignment state is carried out by subjecting the liquid crystal compound thus oriented to a polymerization treatment or a crosslinking treatment.

Specific examples of the liquid crystal compound and the method of forming the oriented solidified layer are described in Japanese Laid-Open Patent Publication No. 2006-163343. The disclosure of such publications is incorporated herein by reference.

D. Second phase difference layer

D-1. Characteristics of the second retardation layer

The second retardation layer 30 may have any suitable optical and / or mechanical properties depending on the purpose. The second retardation layer 30 typically has a slow axis. In one embodiment, the angle formed by the slow axis of the second retardation layer 30 and the absorption axis of the polarizer 11 is preferably 65 ° to 85 °, more preferably 72 ° to 78 °, More preferably about 75 [deg.]. The angle between the slow axis of the second retardation layer 30 and the slow axis of the first retardation layer 20 is preferably 52 ° to 68 °, more preferably 57 ° to 63 °, Lt; / RTI > When the angle formed by the slow axis of the second retardation layer 30 and the absorption axis of the polarizer 11 is in this range, the in-plane retardation of the first retardation layer is set to a predetermined range, By setting the slow axis at a predetermined angle with respect to the absorption axis of the polarizer and setting the in-plane retardation of the second retardation layer to a predetermined range as described later, very excellent circularly polarized light characteristics Can be obtained.

The second retardation layer preferably exhibits a refractive index characteristic of nx > ny > = nz. The in-plane retardation Re (550) of the second retardation layer is preferably 80 nm to 200 nm, more preferably 100 nm to 180 nm, still more preferably 110 nm to 170 nm.

The other characteristics of the second retardation layer are the same as described in the above-mentioned section C-1 with respect to the first retardation layer.

D-2. A second retardation layer made of a resin film

When the second retardation layer is made of a resin film, its thickness is preferably 40 占 퐉 or less, and preferably 25 占 퐉 to 35 占 퐉. When the thickness of the second retardation layer is in this range, a desired in-plane retardation can be obtained. In the case where the second retardation layer is made of a resin film, its material, properties, manufacturing method and the like are the same as described in the above section C-2 with respect to the first retardation layer.

D-3. A second retardation layer constituted of an oriented solidified layer of a liquid crystal compound

The second retardation layer 30 may be an oriented solidified layer of a liquid crystal compound as in the case of the first retardation layer. When the second retardation layer 30 is constituted by an oriented solidified layer of a liquid crystal compound, the thickness thereof is preferably 0.5 m to 2 m, and more preferably 1 m to 1.5 m. When the second retardation layer is composed of an oriented solidified layer of a liquid crystal compound, its material, properties, manufacturing method and the like are the same as described in the above section C-3 with respect to the first retardation layer.

D-4. The combination of the first retardation layer and the second retardation layer

The first retardation layer and the second retardation layer can be used in any suitable combination. Specifically, the first retardation layer may be composed of a resin film and the second retardation layer may be composed of an oriented solidified layer of a liquid crystal compound; The first retardation layer may be composed of an oriented solidified layer of a liquid crystal compound and the second retardation layer may be composed of a resin film; The first retardation layer and the second retardation layer may all be composed of a resin film; The first retardation layer and the second retardation layer may all be composed of an oriented solidified layer of a liquid crystal compound. Preferably, when the first retardation layer is made of a resin film, the second retardation layer is also composed of a resin film; When the first retardation layer is composed of an oriented solidified layer of a liquid crystal compound, the second retardation layer is also composed of an oriented solidified layer of the liquid crystal compound. When both the first retardation layer and the second retardation layer are made of a resin film, the first retardation layer and the second retardation layer may be the same or different in detail. The same applies to the case where both the first retardation layer and the second retardation layer are composed of the oriented solidified layer of the liquid crystal compound.

When both the first retardation layer and the second retardation layer are made of a resin film, the dimensional change ratio of the second retardation layer is preferably 1% or less, more preferably 0.95% or less. The dimensional change ratio of the second retardation layer is preferably as small as possible. The lower limit of the rate of dimensional change of the second retardation layer is, for example, 0.01%. When the dimensional change rate of the second retardation layer is in this range, cracking of the conductive layer under high temperature and high humidity can be remarkably suppressed.

When the first retardation layer and the second retardation layer are both composed of an oriented solidified layer of a liquid crystal compound, the dimensional change ratio of the layered product of the polarizing plate, the first retardation layer and the second retardation layer is preferably 1% or less, It is preferably 0.95% or less. The dimensional change ratio of the laminate is preferably as small as possible. The lower limit of the rate of dimensional change of the laminate is, for example, 0.01%. When the dimensional change ratio of the laminate is in this range, cracking of the conductive layer under high temperature and high humidity can be remarkably suppressed.

E. Pressure-sensitive adhesive layer

The pressure-sensitive adhesive layer may be composed of any suitable pressure-sensitive adhesive as long as the constitution and characteristics described in the above-mentioned section A are satisfied. In other words, the pressure-sensitive adhesive contains any suitable pressure-sensitive adhesive polymer as long as it satisfies the composition and characteristics described in the above section A As the adhesive polymer, a polymer having a Tg of 0 占 폚 or lower (usually -100 占 폚 or higher) is preferable from the viewpoint of easily balancing the viscosity performance. Among such polymers, polyester polymers and (meth) acrylic polymers are preferably used.

As the polyester-based polymer, a saturated polyester or copolyester with a polyhydric alcohol and a polyvalent carboxylic acid can be typically used. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-propanediol, Diols such as 4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-bis (4-hydroxyphenyl) propane and bis (4-hydroxyphenyl) sulfone. Examples of the polycarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, Aromatic dicarboxylic acids such as dicarboxylic acid, diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonic acid and anthracenedicarboxylic acid; Alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid and hexahydroisophthalic acid; But are not limited to, malonic acid, dimethyl malonic acid, succinic acid, 3,3-diethyl succinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, Aliphatic dicarboxylic acids such as acid, dimer acid, sebacic acid, suberic acid, and dodecadicarboxylic acid. As the polycarboxylic acid, two or more polycarboxylic acids such as an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid are often used in combination.

Examples of the acid component in the monomer constituting the polyester-based polymer include polycarboxylic acids having three or more hydroxyl groups. Specific examples include tricarboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid) and 2,5,7-naphthalenetricarboxylic acid; And tetracarboxylic acids such as pyromellitic acid.

As described in the above section A, the amount of the acid component in the total monomer component constituting the polyester polymer is less than 4% by weight, preferably 0 to 3% by weight, more preferably 0 to 2% by weight , More preferably 0 to 1 wt%, and particularly preferably substantially zero. If the amount of the acid component is within this range, the adverse effect of the acid component on the conductive layer becomes negligibly small, and as a result, occurrence of cracks in the conductive layer under high temperature and high humidity can be remarkably suppressed.

The (meth) acryl-based polymer usually contains alkyl (meth) acrylate as a main component as a monomer unit. As the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer, straight chain or branched chain alkyl groups having 1 to 18 carbon atoms can be exemplified. These may be used alone or in combination. The average carbon number of these alkyl groups is preferably from 3 to 9. Further, alkyl (meth) acrylates containing an aromatic ring such as phenoxyethyl (meth) acrylate and benzyl (meth) acrylate can be used. The alkyl (meth) acrylate containing an aromatic ring may be obtained by mixing a polymer obtained by polymerizing the aromatic ring with the (meth) acrylic polymer exemplified above or by copolymerizing the alkyl (meth) acrylate with the alkyl (meth) acrylate. From the viewpoint of transparency, copolymerization is preferable.

(Meth) acryl-based polymer is introduced by copolymerization with one or more kinds of copolymerizable monomers having a polymerizable functional group (for example, an unsaturated double bond such as a (meth) acryloyl group or vinyl group) for the purpose of improving the adhesive force and heat resistance .

Examples of the acid component in the monomer constituting the (meth) acrylic polymer include monomers having an acid group as the copolymerizable monomer. Specific examples include carboxyl group-containing monomers such as acrylic acid, (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; Monomers containing acid anhydride groups such as maleic anhydride and itaconic anhydride; Caprolactone adducts of acrylic acid; Containing sulfonic acid group such as styrene sulfonic acid or allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid Monomers; And a phosphate group-containing monomer such as 2-hydroxyethyl acryloyl phosphate. As the acid component, a carboxyl group-containing monomer which is slightly acidic is preferable from the viewpoint of less adverse effect by an acid.

Any suitable copolymerizable monomer other than the copolymerized monomer may be introduced into the (meth) acryl-based polymer by copolymerization. The kind, number and copolymerization ratio of such a copolymerizable monomer can be appropriately set according to the purpose.

The (meth) acryl-based polymer may be any one of a random copolymer, a block copolymer and a graft copolymer.

As described in the above section A, the amount of the acid component in the total monomer component constituting the (meth) acrylic polymer is less than 4% by weight, preferably 0 to 3% by weight, more preferably 0 to 2% by weight , More preferably 0 to 1 wt%, and particularly preferably substantially zero. If the amount of the acid component is within this range, the adverse effect of the acid component on the conductive layer becomes negligibly small, and as a result, occurrence of cracks in the conductive layer under high temperature and high humidity can be remarkably suppressed.

The pressure-sensitive adhesive may contain a crosslinking agent. As the crosslinking agent, an organic crosslinking agent or a polyfunctional metal chelate can be used. Examples of the organic crosslinking agent include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, and imine crosslinking agents. A polyfunctional metal chelate is a covalent bond or a coordination bond of a polyvalent metal with an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, have. Examples of the atom in the covalent bond or coordination organic compound include an oxygen atom, and examples of the organic compound include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds. As the crosslinking agent, an isocyanate crosslinking agent and a peroxide crosslinking agent are preferable.

Examples of the isocyanate crosslinking agent include isocyanate monomers such as tolylene diisocyanate, chlorophenylenediisocyanate, tetramethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate and the like, and these isocyanate monomers are reacted with trimethylol Propane and the like, isocyanurate compounds, biuret type compounds, and urethane prepolymer type isocyanates which have been subjected to addition reaction such as polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, polyisoprene polyol and the like.

As the peroxide type crosslinking agent, any suitable one can be used as far as it promotes crosslinking of the base polymer of the pressure-sensitive adhesive by generating radical active species by heating or light irradiation. Considering workability and stability, the one-minute half-life temperature of the peroxide type crosslinking agent is preferably 80 ° C to 160 ° C, more preferably 90 ° C to 140 ° C. Specific examples of the peroxide that can be used as the crosslinking agent include di (2-ethylhexyl) peroxydicarbonate (half-life half-hour temperature: 90.6 ° C, di (4-t- butylcyclohexyl) peroxydicarbonate (half- Butyl peroxyneodecanoate (1 minute half life temperature: 103.5 占 폚), t-hexyl peroxy pivalate (1 minute half-life temperature: 92.1 占 폚), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: 109.1 占 폚), t-butyl peroxypivalate (1 minute half life temperature: 110.3 占 폚), dilauroyl peroxide (1 minute half life temperature: 116.4 占 폚), di-n-octanoyl peroxide (Half-life temperature: 117.4 占 폚), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (1 minute half life temperature: 124.3 占 폚), di (4-methylbenzoyl) peroxide Half-life temperature: 128.2 占 폚), dibenzoyl peroxide (one minute half life temperature: 130.0 占 폚), t-butyl peroxyisobutyrate (one minute half life temperature: 136.1 占 폚) Di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C).

A silane coupling agent may be added to the pressure-sensitive adhesive as an additive. Examples of the silane coupling agent include epoxy compounds having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, Silicon compounds; Amino group-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane and N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane; 3-chloropropyltrimethoxysilane; (Meth) acrylic group-containing silane coupling agents such as trimethoxysilane containing acetoacetyl group, 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; And an isocyanate group-containing silane coupling agent such as 3-isocyanatepropyltriethoxysilane.

Details of the pressure-sensitive adhesive are described, for example, in [0023] - [0080] of Japanese Laid-Open Patent Publication No. 2012-247517. The description of the publication is incorporated herein by reference.

(In particular, a high-temperature high-humidity environment) can be obtained by adjusting the kind, number, copolymerization ratio, type of cross-linking agent, kind of additives, number and amount of the monomer components constituting the viscous polymer Crack resistance of the layer) can be obtained.

The thickness of the pressure-sensitive adhesive layer 40 is preferably 5 m to 30 m, and more preferably 5 m to 20 m.

F. Conductive layer or substrate-attached conductive layer

The conductive layer can be formed by depositing a metal oxide film on any suitable substrate by any suitable film forming method (e.g., vacuum deposition, sputtering, CVD, ion plating, spraying, etc.). After the film formation, a heat treatment (for example, 100 ° C to 200 ° C) may be performed as necessary. By performing the heat treatment, the amorphous film can be crystallized. Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide and indium-zinc composite oxide. The indium oxide may be doped with a divalent metal ion or a tetravalent metal ion. Preferably an indium-based composite oxide, and more preferably an indium-tin composite oxide (ITO). The indium based composite oxide has a high transmittance (for example, 80% or more) in a visible light region (380 nm to 780 nm) and a low surface resistance value per unit area.

When the conductive layer contains a metal oxide, the thickness of the conductive layer is preferably 50 nm or less, more preferably 35 nm or less. The lower limit of the thickness of the conductive layer is preferably 10 nm.

The surface resistance value of the conductive layer is preferably 300? / ?, more preferably 150? / ?, still more preferably 100? /? Or less.

The conductive layer may be transferred from the base material to the second retardation layer so that the conductive layer alone may be a constituent layer of the optical laminate or may be laminated to the second retarder layer as a laminate (base conductive layer).

As a material constituting the substrate, any suitable resin may be mentioned. It is preferably a resin having excellent transparency. Specific examples thereof include a cycloolefin resin, a polycarbonate resin, a cellulose resin, a polyester resin and an acrylic resin.

Preferably, the substrate is optically isotropic, and thus the conductive layer can be used in the optical laminate as an electrically conductive layer with an isotropic substrate. Examples of the material constituting the optically isotropic base material (isotropic base material) include a material having a main skeleton of a resin having no conjugated system such as a norbornene resin or an olefin resin, a cyclic structure such as a lactone ring or a glutarimide ring For example, a material having an acryl-based resin in the main chain of the acrylic resin. By using such a material, the occurrence of the phase difference along the molecular chain orientation can be suppressed to a small degree when the isotropic base material is formed.

The thickness of the substrate is preferably 10 to 200 mu m, more preferably 20 to 60 mu m.

Water vapor permeability of the substrate is ^{5mg / m 2 · 24h~10mg / m} 2 · 24h , preferably ^{6mg / m 2 · 24h~9mg / m} 2 · 24h , more preferably from 7mg / m ² · 24h~8mg / m ² · 24h. The rate of dimensional change of the substrate is 0.3% or less, preferably 0.1% or less, and more preferably 0.05% or less. Further, the linear expansion coefficient of the substrate ^{6 (× 10 -6 / ℃)} ~9 (× 10 -6 / ℃) , preferably from ^{7 (× 10 -6 / ℃)} ~8 (× 10 -6 / ℃ )to be. When the above-mentioned characteristics of the base material are in this range, cracking of the conductive layer under high temperature and high humidity can be remarkably suppressed. The moisture permeability can be determined in accordance with the moisture permeability test (cup method) of JIS Z0208. Linear expansion coefficient can be determined by TMA measurement according to JIS K 7197.

The conductive layer and / or the conductive layer of the isotropic substrate with the conductive layer may be patterned as required. Conductive portions and insulating portions can be formed by patterning. As the patterning method, any suitable method can be employed. Specific examples of the patterning method include a wet etching method and a screen printing method.

If necessary, a hard coat layer (not shown) may be provided between the conductive layer 51 and the substrate 52. As the hard coat layer, a hard coat layer having any suitable configuration can be used. The thickness of the hard coat layer is, for example, 0.5 탆 to 2 탆. If the haze is within the allowable range, fine particles for reducing the newton ring may be added to the hard coat layer. If necessary, an anchor coat layer and / or a refractive index adjusting layer for adjusting the reflectance may be provided between the conductive layer 51 and the substrate 52 (hard coat layer, if present) for enhancing the adhesion of the conductive layer . As the anchor coat layer and the refractive index adjusting layer, any suitable configuration can be employed. The anchor coat layer and the refractive index adjusting layer may be a thin layer of several nm to several tens nm.

If necessary, another hard coat layer may be provided on the opposite side of the conductive layer of the base material 52 (the outermost side of the optical laminate). The hard coat layer typically includes a binder resin layer and spherical particles, and spherical particles protrude from the binder resin layer to form protrusions. Details of such a hard coat layer are described in Japanese Laid-Open Patent Publication No. 2013-145547, and the description of such a publication is incorporated herein by reference.

G. Other

The optical laminate according to the embodiment of the present invention may further include another retardation layer. The optical properties (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position and the like of other retardation layers can be appropriately set according to the purpose.

Practically, a pressure-sensitive adhesive layer (not shown) for bonding to the display cell is provided on the surface of the conductive layer 50 (base layer 52 of the conductive layer, if present). It is preferable that the release film is adhered to the surface of the pressure-sensitive adhesive layer until the optical laminate is provided for use.

H. Image display device

The optical laminate described in item A to G of the above can be applied to an image display device. Therefore, the present invention includes an image display apparatus using such an optical laminate. Typical examples of the image display device include a liquid crystal display device and an organic EL display device. The image display apparatus according to the embodiment of the present invention has the optical laminate described in the items A to G above on its viewing side. The optical laminate is laminated such that the conductive layer is on the side of the display cell (liquid crystal cell, organic EL cell, for example) (the polarizer is on the viewing side). That is, the image display apparatus according to the embodiment of the present invention may be a so-called inner touch panel type input display device in which a touch sensor is incorporated between a display cell (e.g., liquid crystal cell, organic EL cell) and a polarizing plate. In this case, the touch sensor can be disposed between the conductive layer (or the substrate-attached conductive layer) and the display cell. The configuration of the touch sensor may be well known in the art, and thus a detailed description thereof will be omitted.

[Example]

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples. The measurement method of each characteristic is as follows.

(1) Thickness

The applied retardation layer (oriented solidified layer of liquid crystal compound) was measured by interference film thickness measurement method using MCPD2000 manufactured by Otsuka Electronics Co., Other films were measured using a digital micrometer (KC-351C manufactured by Anritsu).

(2) The retardation value of the retardation layer

The refractive indexes nx, ny and nz of the retardation layer used in Examples and Comparative Examples were measured by an automatic birefringence measurement apparatus (automatic birefringence system KOBRA-WPR manufactured by Oji Measurement Instruments Co., Ltd.). The measurement wavelength of the in-plane retardation Re was 450 nm and 550 nm, the measurement wavelength of the thickness direction retardation Rth was 550 nm, and the measurement temperature was 23 占 폚.

(3) Storage modulus

With respect to the pressure-sensitive adhesive layer used in Examples and Comparative Examples, the storage modulus at 85 캜 was measured based on JIS K 7244 using a dynamic viscoelasticity measuring apparatus 'ARES' manufactured by Rheometric Company.

(4) Dimensional change rate of retardation layer or optical laminate

The retardation layer used in Examples and Comparative Examples or the optical laminate obtained in Examples and Comparative Examples was cut into 100 mm x 100 mm and used as a measurement sample. The dimension after the sample was stored for 240 hours in an oven at a temperature of 85 캜 and a relative humidity of 85% was measured and the rate of change from the dimension before the oven was introduced into the oven in the direction orthogonal to the longitudinal direction of the roll was regarded as a rate of dimensional change.

(5) Durability of optical laminate

The optical laminate obtained in Examples and Comparative Examples was cut into a size of 100 mm x 50 mm and attached to a non-alkali glass to obtain a measurement sample. The sample to be measured was stored in an oven at a temperature of 85 캜 and a relative humidity of 85% for 120 hours. Thereafter, the measurement sample was removed from the oven, and the state of the conductive layer was observed by a laser microscope and evaluated according to the following criteria.

Good: Cracks were not recognized.

Poor: Crack was recognized significantly.

[Reference Example 1: Production of polarizer]

A long roll of a polyvinyl alcohol (PVA) type resin film (product name "PE3000", manufactured by Kuraray Co., Ltd.) having a thickness of 30 탆 was uniaxially stretched in the longitudinal direction such that it was 5.9 times in the longitudinal direction by a roll stretching machine, , A cleaning treatment was carried out, and finally a drying treatment was carried out to produce a polarizer 1 having a thickness of 12 탆.

More specifically, the swelling treatment was conducted at a stretching ratio of 2.2 times while being treated with pure water at 20 ° C. Then, in the dyeing treatment, the film was stretched to 1.4 times while being treated in an aqueous solution of 30 DEG C at a weight ratio of iodine and potassium iodide adjusted to an iodine concentration of 1: 7 such that the ultraviolet transmittance of the resulting polarizer was 45.0%. The cross-linking treatment was carried out in two stages while the first-stage cross-linking treatment was carried out at 1.2 times while being treated in an aqueous solution of boric acid and potassium iodide dissolved at 40 占 폚. The content of boric acid in the aqueous solution of the crosslinking treatment in the first step was 5.0 wt%, and the content of potassium iodide was 3.0 wt%. The crosslinking treatment in the second step was conducted in an aqueous solution containing boric acid and potassium iodide at 65 DEG C while being stretched to 1.6 times. The content of boric acid in the aqueous solution of the crosslinking treatment in the second step was 4.3% by weight, and the content of potassium iodide was 5.0% by weight. Further, the cleaning treatment was performed with an aqueous solution of potassium iodide at 20 占 폚. The potassium iodide content in the aqueous solution for the washing treatment was 2.6 wt%. Finally, the drying treatment was conducted at 70 캜 for 5 minutes to obtain a polarizer (1).

A TAC film (product name: KC2UA, thickness: 25 mu m, corresponding to the second protective layer) manufactured by Konica Minolta Co., Ltd. was applied to both surfaces of the obtained polarizer 1 via a polyvinyl alcohol adhesive agent and a hard coat treatment (Thickness: 32 탆, corresponding to the first protective layer) having a hard coat (HC) layer formed thereon with the first protective layer / polarizer 1 / second protective layer To obtain a polarizing plate (1).

[Reference Example 2: Production of liquid crystal alignment solidified layer constituting the first retardation layer]

10 g of a polymerizable liquid crystal showing a nematic liquid crystal phase (trade name: 'Palio color LC242', manufactured by BASF) and 10 g of a photopolymerization initiator (trade name: Irgacure 907 manufactured by BASF) ) Was dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid).

[Chemical Formula 1]

The surface of the polyethylene terephthalate (PET) film (38 mu m thick) was subjected to orientation treatment by rubbing with a rubbing cloth. The conditions of the alignment treatment were as follows: the number of rubbing times (the number of rubbing rolls) was 1, the rubbing roll radius r was 76.89 mm, the rubbing roll speed nr was 1,500 rpm, the film conveying speed v was 83 mm / RS and the amount of indentation M were carried out under the five conditions (a) to (e) shown in Table 1.

[Table 1]

The direction of the alignment treatment was -75 ° when viewed from the viewer side with respect to the direction of the absorption axis of the polarizer at the time of conjugation to the polarizer. The liquid crystal coating liquid was coated on this alignment treatment surface by a bar coater and heated and dried at 90 DEG C for 2 minutes to orient the liquid crystal compound. In the conditions (a) to (c), the alignment state of the liquid crystal compound was very good. In the conditions (d) and (e), slight misalignment occurred in the alignment of the liquid crystal compound, but there was no problem in practical use. The thus formed liquid crystal layer was irradiated with light of 1 mJ / cm ² using a metal halide lamp, and the liquid crystal layer was cured to form a retardation layer (liquid crystal alignment solidified layer) 1 on the PET film. The thickness of the retardation layer 1 was 2 탆 and the in-plane retardation Re (550) was 236 nm. Further, the retardation layer 1 had a refractive index distribution of nx > ny = nz.

[Reference Example 3: Preparation of liquid crystal alignment solidified layer constituting the second retardation layer]

The surface of the polyethylene terephthalate (PET) film (38 mu m thick) was subjected to orientation treatment by rubbing with a rubbing cloth. The direction of the alignment treatment was -15 ° when viewed from the viewer side with respect to the direction of the absorption axis of the polarizer at the time of conjugation to the polarizer. The alignment treatment surface was coated with the same liquid crystal coating solution as in Reference Example 2, and the liquid crystal compound was aligned and cured in the same manner as in Reference Example 2 to form a retardation layer (2) on the PET film. The retardation layer 2 had a thickness of 1.2 占 퐉 and the in-plane retardation Re (550) was 115 nm. Further, the retardation layer 2 had a refractive index distribution of nx > ny = nz.

[Reference Example 4: Production of laminated retardation film constituting the first retardation layer and the second retardation layer]

(A) (trade name: KUZ-Film # 270, thickness: 33 μm, Re (550) = 270 nm) manufactured by Kaneka Corporation and a cycloolefin-based retardation film (B) (Thickness: 28 占 퐉, Re (550) = 140 nm) having a thickness of 5 占 퐉 so that the angle formed by the respective slow axes was 60 占 and the laminated retardation film was laminated . This laminated retardation film was used as a retardation layer (3). The dimensional change ratio of the retardation film (retardation film (B)) disposed on the conductive layer side in this laminated retardation film was 0.95%.

[Reference Example 5: Production of retardation film constituting retardation layer]

5-1. Production of polycarbonate resin film

26.5 parts by mass of isophorone diisocyanate (ISB), 100.5 parts by mass of 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene (BHEPF), 1,4-cyclohexanedimethanol ), 105.1 parts by mass of diphenyl carbonate (DPC), and 0.591 parts by mass of cesium carbonate (0.2 mass% aqueous solution) as a catalyst were charged into a reaction vessel, respectively. (Heat medium) was set at 150 ° C., and the raw material was dissolved (about 15 minutes) while stirring as required.

Then, the pressure in the reaction vessel was changed from the atmospheric pressure to 13.3 kPa, and the phenol generated while raising the heat temperature of the reaction vessel to 190 deg. C over 1 hour was taken out of the reaction vessel.

After maintaining the temperature in the reaction vessel at 190 占 폚 for 15 minutes, the pressure in the reaction vessel was set to 6.67 kPa as the second step, the temperature of the reaction vessel was elevated to 230 占 폚 in 15 minutes, And was taken out of the container. As the stirring torque of the stirrer rises, the temperature was raised to 250 ° C in 8 minutes, and the pressure in the reaction vessel was reduced to 0.200 kPa or less in order to remove additional phenol. After reaching a predetermined stirring torque, the reaction was terminated and the resulting reaction product was extruded into water and then pelletized to obtain 47.4 mol% / 37.1 mol% / 15.5 mol% BHEPF / ISB / 1,4- To obtain a carbonate resin.

The obtained polycarbonate resin had a glass transition temperature of 136.6 ° C and a reduced viscosity of 0.395 dL / g.

The obtained polycarbonate resin was vacuum-dried at 80 占 폚 for 5 hours and then dried by a single screw extruder (manufactured by Isuzu Chemical Co., screw diameter 25 mm, cylinder set temperature 220 占 폚), T die (width 200 mm, set temperature 220 占 폚) A polycarbonate resin film having a thickness of 120 占 퐉 was prepared using a film-forming apparatus equipped with a roll (set temperature: 120 to 130 占 폚) and a winding machine.

5-2. Production of phase difference film

The polycarbonate resin film obtained by using a tenter stretching machine was transversely stretched to obtain a retardation film having a thickness of 50 占 퐉. At that time, the stretching magnification was 250% and the stretching temperature was 137 to 139 占 폚.

Re (550) of the obtained retardation film was 137 to 147 nm, Re (450) / Re (550) was 0.89, Nz coefficient was 1.21, and the orientation angle (direction of the slow axis) was 90 degrees with respect to the long axis direction. This retardation film was used as the retardation layer 4. The dimensional change ratio of the retardation film according to (4) was 1.6%.

[Reference Example 6: Production of conductive film (base-attached conductive layer)] [

A polycycloolefin film (trade name "ZEONOR (registered trademark)", manufactured by Zeon Corporation, Japan) having a thickness of 50 μm was used as a substrate. An ultraviolet ray curable resin composition (trade name: UNIDIC (registered trademark) RS29-120 ') was coated on one side of this substrate, dried at 80 DEG C for 1 minute, and then cured by ultraviolet rays to obtain a hard coat Layer. Subsequently, 100 parts by weight of the same ultraviolet-curable resin composition as above, and 0.002 wt% of acrylic spherical particles (trade name: MX-180TA, manufactured by Soken Chemical & Engineering Co., Ltd.) having a minimum particle diameter of 1.9 μm Containing spherical particle-containing curable resin composition was coated thereon and then cured by ultraviolet rays to form a hard coat layer having a thickness of 1.0 탆. The polycycloolefin film obtained above was charged into a sputtering apparatus to form an amorphous layer of indium tin oxide having a thickness of 27 nm on the surface of the hard coat layer not containing particles. Subsequently, the polyolefin film on which the amorphous layer of indium tin oxide was formed was heat-treated in a heating oven at 130 캜 for 90 minutes to prepare a transparent conductive film having a surface resistance of 100? / ?. This transparent conductive film was used as the substrate-attached conductive layer.

Reference Example 7: Fabrication of conductive film (substrate-attached conductive layer)

A transparent conductive film having a surface resistance of 100? /? Was prepared in the same manner as in Reference Example 5 except that a PET film having a thickness of 50 占 퐉 (Lumirra # 50, manufactured by Toray Industries, Inc.) was used. This transparent conductive film was used as the substrate-attached conductive layer.

[Reference Example 8: Production of pressure-sensitive adhesive layer]

To the reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer were added 99 parts of butyl acrylate, 1.0 part of 4-hydroxybutyl acrylate and 0.3 part of 2,2'-azobisisobutyronitrile together with ethyl acetate . The mixture in the reaction vessel was reacted at 60 DEG C for 4 hours in a stream of nitrogen gas, and ethyl acetate was added to the reaction solution to obtain a solution (solid content concentration: 30%) containing an acrylic polymer having a weight average molecular weight of 1,600,000. 0.15 part of dibenzoyl peroxide (NYPER-BO-Y, manufactured by Nippon Oil and Fats Co., Ltd.) and 0.1 part of trimethylolpropane xylene diisocyanate (manufactured by Mitsui Takeda Chemical Co., Ltd.) were added to 100 parts of solid content of the acryl- Nate D110N) and 0.2 part of a silane coupling agent (A-100, manufactured by Soken Chemical & Engineering Co., Ltd., acetoacetyl group-containing silane coupling agent) were blended to obtain a pressure-sensitive adhesive layer forming solution. The solution for forming a pressure-sensitive adhesive layer was coated on a separator composed of a polyester film surface-treated with a silicone-based releasing agent and heat-treated at 155 캜 for 3 minutes to obtain a pressure-sensitive adhesive layer (A) with a thickness of 15 탆. The storage elastic modulus of the pressure-sensitive adhesive layer (A) according to the above (3) was 5.3 x 10 < ⁴ >

[Referential Example 9: Production of pressure-sensitive adhesive layer]

A reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer was charged with 94.9 parts of butyl acrylate, 5 parts of acrylic acid, 0.1 part of acrylic acid 2-hydroxyethyl and 0.3 parts of benzoyl peroxide The oxide was added with ethyl acetate. The mixture in the reaction vessel was reacted at 60 DEG C for 7 hours under a nitrogen gas stream, and ethyl acetate was added to the reaction solution to obtain a solution (solid concentration 30% by weight) containing an acrylic polymer having a weight average molecular weight of 2,200,000. 0.6 part of trimethylolpropane tolylene diisocyanate (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) and 0.075 part of? -Glycidoxypropylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) per 100 parts of the solid content of the acryl- KBM-403) was blended to obtain a solution for forming a pressure-sensitive adhesive layer. The solution for forming the pressure-sensitive adhesive layer was coated on a separator made of a polyester film surface-treated with a silicone-based releasing agent and heat-treated at 155 캜 for 3 minutes to obtain a pressure-sensitive adhesive layer (B) with a thickness of 15 탆. The storage elastic modulus of the pressure-sensitive adhesive layer (B) according to the above (3) was 8.3 10 ⁴ Pa.

[Example 1]

The second protective layer surface of the polarizing plate 1 and the retardation layer 1 were bonded via an acrylic adhesive agent having a thickness of 5 占 퐉 so that the absorption axis of the polarizer and the slow axis of the retardation layer 1 made an angle of 15 ° . Subsequently, the PET film on which the retardation layer 1 was formed was peeled off. The retardation layer 2 was peeled off to a thickness of 5 占 퐉 so that the absorption axis of the polarizer and the retardation axis of the retardation layer 2 made an angle of 75 占Of an acrylic adhesive. Further, the PET film on which the retardation layer 2 was formed was peeled off to obtain a circularly polarizing plate 1 having the configuration of the polarizing plate / first retardation layer / second retardation layer. The dimensional change ratio of the circularly polarizing plate 1 according to the above (4) was 0.20%. The second retardation layer of the circularly polarizing plate 1 and the conductive layer of the base material-adhered conductive layer obtained in Reference Example 6 were bonded to each other via the pressure-sensitive adhesive layer (A) to obtain an optical laminate (1). The obtained optical laminate (1) was subjected to the evaluation of the above (5). The results are shown in Table 2.

[Example 2]

The surface of the second protective layer surface of the polarizing plate 1 and the surface of the retardation film A were set to be in phase with the absorption axis of the polarizer using the retardation layer 3 (laminated retardation film) in place of the retardation layers 1 and 2, The film A was laminated via an acrylic adhesive having a thickness of 12 占 퐉 so that the angle formed by the slow axis of the film A was 15 占 and the angle between the absorption axis of the polarizer and the slow axis of the retardation film B was 75 占, / The first retardation layer / the second retardation layer. The second retardation layer of the circularly polarizing plate 2 and the conductive layer of the base material-adhered conductive layer obtained in Reference Example 6 were bonded together via the pressure-sensitive adhesive layer (A) to obtain an optical laminate (2). The obtained optical laminate (2) was subjected to the evaluation of the above (5). The results are shown in Table 2.

[Comparative Example 1]

The second protective layer surface of the polarizing plate 1 and the retardation layer 4 were laminated via an acrylic adhesive having a thickness of 12 占 퐉 so that the absorption axis of the polarizer and the slow axis of the retardation layer 4 made an angle of 45 占, / Retardation layer (circular polarizer plate 3). The retardation layer of the circularly polarizing plate 3 and the conductive layer of the base material-adhered conductive layer obtained in Reference Example 6 were bonded together via the pressure-sensitive adhesive layer (B) to obtain an optical laminate (3). The obtained optical laminate (3) was subjected to the evaluation of the above (5). The results are shown in Table 2.

[Table 2]

* COP is a cycloolefin resin film, and PC is a polycarbonate resin film.

** The dimensional change rate of the retardation layer is the rate of dimensional change of the circularly polarized plate in the case of the liquid crystal alignment solidified layer and the dimensional change rate of the retardation layer in contact with the conductive layer.

<Evaluation>

As can be seen from Table 2, in the optical laminate of the embodiment of the present invention, cracks in the conductive layer under high temperature and high humidity are remarkably suppressed.

[Industrial Availability]

The optical laminate of the present invention is preferably used in an image display apparatus such as a liquid crystal display apparatus and an organic EL display apparatus, and can be preferably used particularly as an antireflection film of an organic EL display apparatus. Further, the optical laminate of the present invention can be preferably used for an inner touch panel type input display device.

10: polarizer
11: Polarizer
12: first protective layer
13: second protective layer
20: first retardation layer
30: second retardation layer
40: pressure-sensitive adhesive layer
50: conductive layer
100: Optical laminate

Claims (7)

A polarizing plate comprising a polarizer and a protective layer on at least one side of the polarizer,
A first retardation layer, a second retardation layer, and a conductive layer in this order
A pressure sensitive adhesive layer for bonding the second retardation layer and the conductive layer is provided,
Wherein the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive polymer,
The amount of the acid component in the total monomer component constituting the viscous polymer is less than 4% by weight,
The storage elastic modulus at 85 ℃ of the adhesive of ^{1.0 × 10 4 Pa~7.0 × 10 4} Pa
Optical laminate. The method according to claim 1,
Wherein an angle between the absorption axis of the polarizer and the slow axis of the first retardation layer is 10 to 20 and an angle formed by the absorption axis and the slow axis of the second retardation layer is 65 to 85 . 3. The method according to claim 1 or 2,
Wherein the first retardation layer and the second retardation layer are composed of a cyclic olefin based resin film. The method of claim 3,
And the dimensional change ratio of the second retardation layer is 1% or less. 3. The method according to claim 1 or 2,
Wherein the first retardation layer and the second retardation layer are oriented solidified layers of a liquid crystal compound
Optical laminate. 6. The method of claim 5,
And the dimensional change ratio of the laminate of the polarizing plate, the first retardation layer and the second retardation layer is 1% or less. An image display apparatus comprising the optical laminate according to any one of claims 1 to 6.

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