JP2007322498A - Elliptically polarizing plate, method of manufacturing elliptically polarizing plate, liquid crystal display device and electroluminescence display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elliptically polarizing plate which does not cause malfunction such as delamination even under conditions of high temperature and high humidity by simplifying a layer structure of the elliptically polarizing plate. <P>SOLUTION: The elliptically polarizing plate comprises: a transmissive protection film; a polarizing element; and an optically anisotropic element, stacked in this order, wherein the optically anisotropic element includes a liquid crystal layer in which a liquid crystalline composition at least exhibiting an optically positive uniaxiality is subjected to twist-nematic alignment in the liquid crystalline state and thereafter the alignment is fixed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an elliptically polarizing plate comprising an optically anisotropic element having a liquid crystal layer in which a twisted nematic alignment structure is fixed, and a method for producing the same. Furthermore, the present invention relates to a liquid crystal display device and an electroluminescence display device using the elliptically polarizing plate.

  The liquid crystal display device has the advantages of being thin and light and having low power consumption. For example, the STN type liquid crystal display device has not achieved full black and white display, but the TN type liquid crystal display device has insufficient viewing angle characteristics. For example, a liquid crystal display device having excellent display performance has not been realized yet. Several means for improving the display performance of the liquid crystal display device have been proposed. One of them is a method of disposing a retardation film between the polarizing plate and the liquid crystal cell of the liquid crystal display device. This method has the advantage that it can be simply implemented without significantly changing the manufacturing process of the liquid crystal display device, simply by laminating a retardation film on the polarizing plate to form an elliptical polarizing plate. However, the thickness increases by the amount of the retardation film and the adhesive / adhesive layer for laminating it, and when it is wound on a roll in the manufacturing process of an elliptically polarizing plate, the amount of winding per roll is reduced and productivity is reduced. There is a problem that it gets worse, and a problem that the thickness of the liquid crystal panel of the final product increases.

  Moreover, since it is composed of a plurality of different types of layers, there are cases in which the interface between the polarizing plate and the retardation film is peeled off in various reliability tests due to the difference in expansion and contraction behavior due to heat and humidity of each layer. Conventionally, most retardation films use polymer films obtained by uniaxial stretching orientation of polycarbonate or the like, and their orientation axes in a long film form are usually limited to the stretching direction, that is, the MD direction. On the other hand, since the polarizing plate also uses a uniaxially stretched film such as polyvinyl alcohol, the absorption axis in the long film form is usually limited to the MD direction. Therefore, when an elliptically polarizing plate is manufactured by continuously laminating a polarizing plate and a retardation film from a long film form, it is limited to a special case where the absorption axis of the polarizing plate and the orientation axis of the retardation film are parallel. It was. In order to make the shaft arrangement other than parallel, it is necessary to cut out and paste the long film into a sheet, and there is a problem that the process is complicated and the productivity is poor. Furthermore, in the stretched and oriented retardation film, it is difficult to freely control the orientation of the polymer, and the degree of freedom in optical properties is limited. As described above, the demand for an elliptically polarizing plate having various axes of the absorption axis of the polarizing plate and the orientation axis of the retardation film and excellent in optical performance could not be sufficiently met.

On the other hand, in the retardation film using a liquid crystal compound, restrictions on the alignment axis are reduced. For example, optical anisotropic elements in which a liquid crystalline polymer is aligned and fixed have been proposed (Patent Documents 1 and 2). ). Furthermore, a quarter-wave plate made of a liquid crystal film in which a twisted nematic alignment structure is fixed has been proposed (Patent Documents 3 and 4).
When such a liquid crystalline polymer is used, the orientation axis angle can be arbitrarily set, so that various elliptical polarizing plates can be produced by continuously laminating from a long film form. However, as described above, the thickness of the elliptically polarizing plate is increased, and in some cases, the interface between the polarizing plate and the optical anisotropic element is peeled off under high temperature or high humidity conditions.
JP-A-4-57017 JP-A-6-242317 Japanese Patent Application Laid-Open No. 2002-48917 Japanese Patent Laid-Open No. 2004-309904

  The object of the present invention is to simplify the layer structure of the elliptically polarizing plate, thereby suppressing the thickness, preventing occurrence of defects such as peeling even under high temperature and high humidity conditions, and further aligning the optical anisotropic element. An elliptically polarizing plate that can be bonded continuously from a long film by setting an axial angle arbitrarily with respect to the absorption axis of the polarizing plate, a manufacturing method thereof, a liquid crystal display device and an electroluminescence display device using the same Is to provide.

That is, the first of the present invention is an elliptically polarizing plate in which a light-transmitting protective film, a polarizing element and an optical anisotropic element are laminated in this order, and the optical anisotropic element exhibits at least positive uniaxiality. The present invention relates to an elliptically polarizing plate comprising a twisted nematic alignment liquid crystal layer in which a liquid crystal composition is twisted nematically aligned in a liquid crystal state and then the alignment is fixed.
A second aspect of the present invention relates to the elliptically polarizing plate according to the first aspect of the present invention, wherein the translucent protective film, the polarizing element and the optical anisotropic element are in the form of a long film.
In the third aspect of the present invention, the twist angle θ of the twisted nematic alignment liquid crystal layer is in the range of 5 ° to 400 °, and the product of the refractive index anisotropy Δn of the twisted nematic alignment liquid crystal layer and the thickness d of the liquid crystal layer ( (DELTA) n * d) is the range of 50 nm-1500 nm, It is related with the elliptically polarizing plate as described in the 1st or 2 of this invention.
A fourth aspect of the present invention relates to the elliptically polarizing plate according to any one of the first to third aspects of the present invention, wherein the translucent protective film is triacetyl cellulose.
A fifth aspect of the present invention relates to the elliptically polarizing plate according to any one of the first to third aspects of the present invention, wherein the translucent protective film is a cycloolefin polymer.

6th of this invention is related with the elliptically polarizing plate in any one of 1st-5th of this invention characterized by the thickness of an elliptically polarizing plate being 150 micrometers or less.
A seventh aspect of the present invention is that any one of the first to sixth aspects of the present invention is characterized in that an alignment film in which the liquid crystalline composition forms a nematic alignment is provided between the polarizing element and the optical anisotropic element. It relates to the elliptically polarizing plate.
An eighth aspect of the present invention is the ellipse according to any one of the first to seventh aspects of the present invention, wherein a translucent overcoat layer is provided on the surface of the optically anisotropic element opposite to the polarizing element. It relates to a polarizing plate.
A ninth aspect of the present invention relates to the elliptically polarizing plate according to the eighth aspect of the present invention, wherein the translucent overcoat layer is made of an acrylic resin.
According to a tenth aspect of the present invention, in any one of the first to ninth aspects of the present invention, the alignment direction of the liquid crystal molecules in the vicinity of one of the both side interfaces of the twisted nematic alignment liquid crystal layer is not parallel to the MD direction. The elliptically polarizing plate as described in 2. above.
The eleventh aspect of the present invention relates to an elliptically polarizing plate, wherein at least one optical film is further laminated on the elliptically polarizing plate according to any one of the first to tenth aspects of the present invention.

According to the twelfth aspect of the present invention, (1) a laminate (A) comprising a translucent protective film / adhesive layer 1 / polarizing element, wherein the translucent protective film is adhered to the polarizing element via the adhesive layer 1. A first step of obtaining
(2) An optical anisotropy in which a layer made of a liquid crystalline composition exhibiting at least positive uniaxiality is formed on an alignment substrate subjected to rubbing treatment, the layer is twisted nematically aligned, and the alignment is fixed A second step of forming an element to obtain a laminated body (B) composed of an alignment substrate / optically anisotropic element, (3) the optically anisotropic element side of the laminated body (B) through the adhesive layer 2 After adhering to the polarizing element side of the laminate (A), the alignment substrate is peeled off to transfer the optical anisotropic element to the laminate (A), and the transparent protective film / adhesive layer 1 / polarized light. It is related with the manufacturing method of the elliptically polarizing plate characterized by passing at least each process of the 3rd process of obtaining the elliptically polarizing plate which consists of element / adhesive layer 2 / optically anisotropic element.

According to the thirteenth aspect of the present invention, (1) a laminate (A) comprising a translucent protective film / adhesive layer 1 / polarizing element, wherein the translucent protective film is adhered to the polarizing element via the adhesive layer 1. A first step of obtaining
(2) The polarizing element surface of the laminate (A) is rubbed to form a layer made of a liquid crystalline composition exhibiting at least positive uniaxiality, and the layer is twisted nematically aligned. A fixed optical anisotropic element is formed, and at least the second process of obtaining an elliptically polarizing plate composed of a translucent protective film / adhesive layer 1 / polarizing element / optical anisotropic element is performed. To an elliptically polarizing plate manufacturing method.

A fourteenth aspect of the present invention is characterized in that, in the thirteenth aspect of the present invention, a rubbing treatment is performed after providing an alignment film on which a liquid crystalline composition exhibiting at least positive uniaxiality forms a nematic alignment on a polarizing element. The present invention relates to a method for producing an elliptically polarizing plate according to the thirteenth aspect of the present invention.
A fifteenth aspect of the present invention relates to the method for producing an elliptically polarizing plate according to the twelfth or thirteenth aspect of the present invention, wherein the translucent protective film is triacetyl cellulose or a cycloolefin polymer.
A sixteenth aspect of the present invention relates to the method for producing an elliptically polarizing plate according to the twelfth or thirteenth aspect of the present invention, wherein the translucent protective film is surface-treated.
A seventeenth aspect of the present invention relates to the method for producing an elliptically polarizing plate according to the twelfth or thirteenth aspect of the present invention, wherein the surface treatment is a saponification treatment or a corona discharge treatment.
An eighteenth aspect of the present invention relates to a liquid crystal display device in which the elliptically polarizing plate according to any one of the first to eleventh aspects of the present invention is disposed on at least one surface of a liquid crystal cell.
A nineteenth aspect of the present invention relates to an electroluminescence display device comprising the elliptically polarizing plate according to any one of the first to eleventh aspects of the present invention.

  The elliptically polarizing plate of the present invention is excellent in adhesiveness of the optical anisotropic element because the optical anisotropic element layer is hardly damaged in the step of bonding the optical anisotropic element and the polarizing element. Furthermore, since the number of laminate layers constituting the elliptically polarizing plate is small, there is no peeling or generation of bubbles at the interface in the durability test. Also in the bonding step with the polarizing element, since it can be bonded in the form of a long film, there is an advantage that the bonding step can be rationalized from the conventional method.

The present invention is described in detail below.
In the present invention, an elliptically polarizing plate is produced by adhering an optically anisotropic element to a polarizing element directly or via an adhesive. By doing so, the number of layers can be reduced as compared with an elliptical polarizing plate in which an optical anisotropic element is bonded to a polarizing plate in which both sides of the polarizing element are protected with an optical film such as a triacetyl cellulose film. . As a result, the total thickness of the elliptically polarizing plate can be reduced, and the influence of shrinkage strain caused by the expansion and contraction of each layer due to heat or humidity can be reduced, and problems such as peeling at the bonded interface can be eliminated. .

The layer structure of the elliptically polarizing plate obtained in the present invention is composed of any of the following structures (I) to (II), and members such as a translucent overcoat layer are further added as necessary. However, except that a liquid crystal composition exhibiting positive uniaxiality in the present invention is twisted nematically aligned in a liquid crystal state and an optical anisotropic element comprising a twisted nematic alignment liquid crystal layer in which the alignment is fixed is used. There are no particular restrictions. In terms of obtaining an elliptically polarizing plate having a small thickness, any of the configurations (I) to (II) may be used.
(I) Translucent protective film / adhesive layer 1 / polarizing element / adhesive layer 2 / optical anisotropic element (II) Translucent protective film / adhesive layer 1 / polarizing element / optical anisotropic element

Hereafter, the structural member used for this invention is demonstrated in order.
First, the liquid crystal composition used in the present invention will be described.
The liquid crystalline composition constituting the optically anisotropic element used in the elliptically polarizing plate of the present invention is, for example, a liquid crystalline composition mainly composed of a liquid crystalline polymer aligned on an alignment substrate with a glass transition temperature (Tg). ) It can be obtained by cooling below and fixing the orientation. As such a liquid crystalline polymer, a thermotropic liquid crystal polymer that exhibits liquid crystallinity when melted is used. The thermotropic liquid crystal polymer used is required to maintain the molecular alignment state of the liquid crystal phase even when cooled from the molten state (liquid crystal state) to Tg or less.
The liquid crystal phase at the time of melting of the liquid crystalline polymer may be any molecular alignment structure such as smectic, nematic, twisted nematic, cholesteric, and the like, and the homogeneous alignment and homeotropic alignment states near the alignment substrate and near the air interface, respectively. So-called hybrid orientation in which the average director of the liquid crystalline polymer is inclined from the normal direction of the film may be used.

  As the liquid crystalline polymer, various main chain type liquid crystalline polymers, side chain type liquid crystalline polymers, or a mixture thereof can be used. Main chain type liquid crystalline polymers include polyester, polyamide, polycarbonate, polyimide, polyurethane, polybenzimidazole, polybenzoxazole, polybenzthiazole, polyazomethine, polyesteramide, polyester carbonate And a polyesterimide-based liquid crystalline polymer, or a mixture thereof. Among these, semi-aromatic polyester liquid crystalline polymers in which mesogenic groups that give liquid crystallinity and bent chains such as polymethylene, polyethylene oxide, and polysiloxane are alternately bonded, or wholly aromatic polyester-based liquid crystals without bent chains. A functional polymer is desirable in the present invention. In addition, as the side chain type liquid crystalline polymer, as a side chain on a substance having a linear or cyclic structure skeleton chain such as polyacrylate, polymethacrylate, polyvinyl, polysiloxane, polyether, polymalonate, etc. Examples thereof include a liquid crystalline polymer having a mesogenic group bonded thereto, or a mixture thereof. Among these, a side chain type liquid crystalline polymer in which a mesogenic group that gives liquid crystallinity is bonded to a skeleton chain through a spacer made of a bent chain, and a liquid crystal structure having a molecular structure having a mesogen in both the main chain and the side chain. Molecules are desirable in the present invention.

In addition, the liquid crystalline composition has a liquid crystalline property in which a chiral agent is added to the composition or various liquid crystal materials or non-liquid crystal materials having at least one chiral structural unit are added to induce twisted nematic alignment. It is particularly desirable that it is a composition.
Examples of the chiral structural unit include optically active 2-methyl-1,4-butanediol, 2,4-pentanediol, 1,2-propanediol, 2-chloro-1,4-butanediol, and 2-fluoro. -1,4-butanediol, 2-bromo-1,4-butanediol, 2-ethyl-1,4-butanediol, 2-propyl-1,4-butanediol, 3-methylhexanediol, 3-methyl A structural unit derived from adipic acid, a naproxen derivative, camphoric acid, binaphthol, menthol, or the like, or a cholesteryl group-containing structural unit or a derivative thereof (for example, a derivative such as a diacetoxy compound) can be used. The structural unit may be either R-form or S-form, or a mixture of R-form and S-form. These structural units are merely examples, and the present invention is not limited thereto.

  In addition, even in the case of oligomers and low-molecular liquid crystals, thermal crosslinking, photocrosslinking, etc. in a state where the liquid crystal state or the liquid crystal transition temperature is cooled to below the liquid crystal transition temperature and the orientation is fixed by introducing a crosslinkable group or by blending an appropriate crosslinking agent. Those that can be polymerized by the above means are also included in the liquid crystalline polymer. Even a discotic liquid crystal compound can be used without any problem. As the liquid crystalline polymer, those that exhibit optically positive or negative uniaxiality are usually used. These optical characteristics are appropriately selected depending on the function required for the optical anisotropic element, but in the case of a polymer liquid crystal layer with twisted nematic alignment, a liquid crystalline polymer exhibiting positive uniaxiality is preferably used.

  Low molecular liquid crystals include Schiff base, biphenyl, terphenyl, ester, thioester, stilbene, tolan, azoxy, azo, phenylcyclohexane, pyrimidine, cyclohexylcyclohexane, trimesic acid, Examples thereof include a low-molecular liquid crystal compound having a triphenylene-based, torquesen-based, phthalocyanine-based, or porphyrin-based molecular skeleton, or a mixture of these compounds. In addition, when the liquid crystalline composition comprising the above various liquid crystal compounds contains a polymerizable group such as a vinyl group, a (meth) acryloyl group, an epoxy group, or an oxetanyl group, it is suitable for each polymerizable group. It is preferable to add various reaction initiators that do not impair the object of the invention, for example, various radical initiators and cation generators.

The Tg of the liquid crystalline composition is preferably room temperature or higher, and more preferably 50 ° C. or higher, because it affects the alignment stability after alignment fixation. Tg can be adjusted by a liquid crystalline polymer, a low molecular liquid crystal used in the liquid crystalline composition, a chiral agent, various compounds as required, or the like, but may be by a crosslinking means as described above.
The various compounds added as necessary may be any compound that does not hinder the alignment of the liquid crystalline composition used in the present invention and does not depart from the purpose of the present invention. Examples include leveling agents, surfactants, and stabilizers for uniform formation.

Next, the alignment substrate will be described.
Examples of the alignment substrate include thermosetting resins such as polyimide, epoxy resin, and phenol resin, polyamide; polyetherimide; polyetherketone; polyetheretherketone (PEEK); polyketone; polyethersulfone; polyphenylene sulfide; Polyester films such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polyacetals; polycarbonates; poly (meth) acrylates; and polymer films exemplified by thermoplastic resins such as polyvinyl alcohol can be used. Moreover, in order to control the orientation of the liquid crystalline composition on the surface of the polymer film, an organic thin film made of a resin such as polyvinyl alcohol or a polyimide derivative may be formed. The polymer film is subjected to an alignment process such as a rubbing process and is provided on an alignment substrate.

As described above, the rubbing treatment is usually performed to align the liquid crystalline composition on the alignment substrate. The rubbing process can be performed at a predetermined arbitrary angle with respect to the MD direction of the long alignment substrate. The angle of the rubbing direction with respect to the MD direction is appropriately set according to the function of the optical anisotropic element. However, when the function as a color compensator is required, the rubbing is usually performed obliquely with respect to the MD direction. Is preferred. The angle in the oblique direction is preferably in the range of −45 degrees to +45 degrees.
The rubbing treatment can be performed by an arbitrary method. For example, a rubbing roll is arranged at an arbitrary angle with respect to the MD direction of the long film on a stage that conveys the long film in the MD direction. The rubbing roll is rotated while being conveyed in the MD direction to rub the film surface. The angle formed by the rubbing roll and the moving direction of the stage is a mechanism that can be freely adjusted, and an appropriate rubbing cloth material is stuck on the surface of the rubbing roll.

Examples of the method for forming the liquid crystalline composition layer by spreading the liquid crystalline composition on the rubbing surface of the alignment substrate include, for example, a method in which the liquid crystalline composition is dissolved in an appropriate solvent and applied or dried, or a T-die For example, a method of directly melting and extruding the liquid crystalline composition may be used. From the standpoint of film thickness uniformity, a solution coating and drying method is suitable. The method for applying the solution of the liquid crystalline composition is not particularly limited, and for example, a die coating method, a slot die coating method, a slide die coating method, a roll coating method, a bar coating method, a dip pulling method, or the like can be employed.
After coating, after removing the solvent by an appropriate drying method, the liquid crystalline composition is twisted nematically aligned by heating at a predetermined temperature for a predetermined time, and then cooled to Tg or lower, or suitable for the liquid crystalline composition used. In addition, for example, a liquid crystalline composition layer in which the orientation is fixed can be formed by performing reaction (curing) by light irradiation and / or heat treatment and fixing.

As a light irradiation method, light from a light source such as a metal halide lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, an arc lamp, or a laser having a spectrum in the absorption wavelength region of the used reaction initiator is irradiated. The dose per square centimeter is usually in the range of 1 to 2000 mJ, preferably 10 to 1000 mJ as the cumulative dose. However, this is not the case when the absorption region of the reaction initiator and the spectrum of the light source are significantly different, or when various compounds constituting the liquid crystalline composition have the ability to absorb the light source wavelength. In these cases, an appropriate photosensitizer, or a mixture of two or more reaction initiators having different absorption wavelengths may be used.
The temperature at the time of light irradiation is preferably in the temperature range in which the liquid crystalline composition becomes a liquid crystal phase. In order to sufficiently enhance the curing effect, light irradiation is performed at a temperature equal to or higher than Tg of the liquid crystalline composition. preferable.

  The liquid crystal layer constituting the optically anisotropic element has a layer in which a twisted nematic alignment structure having an optical anisotropic axis and a structure in which the optical anisotropic axis is twisted from one surface to the other surface is fixed. means. Therefore, this optically anisotropic element has characteristics equivalent to those obtained by stacking layers having optical anisotropy in multiple layers so that the optically anisotropic axis is continuously twisted. Like a twisted nematic liquid crystal cell and an STN (super twisted nematic) liquid crystal cell, it has retardation (= Δnd: a value represented by the product of birefringence Δn and thickness d) and a twist angle. Further, that the alignment structure is fixed means that the alignment structure is not disturbed under the use conditions and is maintained. A similar alignment state can be produced in a liquid crystal cell, but fixing the alignment structure eliminates the need for a substrate such as glass in the liquid crystal cell, and can achieve weight reduction, thinning, improved handling, and the like. The optically anisotropic element may preferably be a temperature-compensated element in which the retardation changes when the temperature environment changes, and the retardation also returns when the temperature is returned to the original temperature.

The product (Δn · d) of the birefringence Δn and the thickness d (nm) and the twist angle of the twisted nematic alignment liquid crystal layer depend on whether the application used is a liquid crystal display device or an electroluminescence display device. However, it is desirable in terms of optical characteristics that Δn · d for light having a wavelength of 550 nm is 50 nm to 1500 nm and the twist angle is 5 degrees to 400 degrees.
The film thickness of the twisted nematic alignment liquid crystal layer is not particularly limited as long as the function of the optical anisotropic element is exhibited, and is suitably about 0.05 μm to 50 μm, preferably about 0.1 μm to 30 μm. .

  Furthermore, for example, when an STN-LCD type liquid crystal display device is used, the Δn · d and twist angle of the twisted nematic alignment liquid crystal layer also depend on the retardation and twist angle of the liquid crystal cell to be used. However, it is preferably 400 nm or more and 1200 nm or less and 120 degrees or more and 300 degrees or less, more preferably 500 nm or more and 1000 nm or less and 160 degrees or more and 260 degrees or less, and further preferably 600 nm or more and 850 nm or less and 170 degrees or more and 250 degrees or less. It is desirable that Further, the twist direction of the twisted nematic alignment liquid crystal layer is preferably opposite to the twist direction of the liquid crystal cell.

  In addition, for example, when used as an antireflection film for a liquid crystal display device or an electroluminescence display device, the twisted nematic alignment liquid crystal layer Δn · d with respect to light having a wavelength of 550 nm is 140 nm or more and 300 nm in that it has a good circular polarization characteristic. The twist angle is preferably 30 degrees or more and 85 degrees or less, and (1) 155 nm or more and 175 nm or less and 40 degrees or more and 50 degrees or less, and (2) 176 nm or more and 216 nm or less and 58 degrees or more and 70 degrees or less. (3) It is particularly preferable that one of the conditions of 230 nm or more and 270 nm or less and 70 degrees or more and 80 degrees or less is satisfied. There are two types of twisting directions, but they may be right-handed or left-handed.

Next, the adhesive layer or translucent overcoat layer used in the present invention will be described.
As a material for forming an adhesive layer or an overcoat layer provided on a twisted nematic alignment liquid crystal layer or a polarizing element, sufficient adhesion to a twisted nematic alignment liquid crystal layer, a polarizing element, or a light-transmitting protective film, etc. As long as the optical properties of the twisted nematic alignment liquid crystal layer and the like are not impaired, for example, acrylic resin, methacrylic resin, epoxy resin, ethylene-vinyl acetate copolymer system, Various reactive types such as rubber-based, urethane-based, polyvinyl ether-based and mixtures thereof, thermosetting type and / or photocurable type, and electron beam curable type can be exemplified. These adhesive layers include those having the function of a transparent protective layer (overcoat layer) that protects the twisted nematic alignment liquid crystal layer. A pressure-sensitive adhesive can be used as the adhesive.

Since the reaction (curing) conditions for the reactive substances vary depending on the components constituting the adhesive, the viscosity, the reaction temperature, and the like, the conditions suitable for each may be selected. For example, in the case of a photo-curing type, various known photoinitiators are preferably added, and light from a light source such as a metal halide lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, a xenon lamp, an arc lamp, a laser, or a synchrotron radiation source is used. Irradiation may be performed to cause the reaction. The amount of irradiation per unit area (one square centimeter) is usually in the range of 1 to 2000 mJ, preferably 10 to 1000 mJ as the integrated irradiation amount. However, this is not the case when the absorption region of the photoinitiator and the spectrum of the light source are significantly different, or when the reactive compound itself has the ability to absorb the light source wavelength. In these cases, an appropriate photosensitizer or a method of using a mixture of two or more photoinitiators having different absorption wavelengths can be used. The acceleration voltage in the case of the electron beam curable type is usually 10 kV to 200 kV, preferably 50 kV to 100 kV.
The thickness of the adhesive layer and the overcoat layer varies depending on the components constituting the adhesive, the strength of the adhesive, the operating temperature, etc. as described above, but is usually 1 to 30 μm, more preferably 3 to 10 μm. Outside this range, the adhesive strength is insufficient, or bleeding from the end is not preferable.

These adhesives can also contain various fine particles and surface modifiers for the purpose of controlling the optical properties or controlling the peelability and erosion properties of the substrate as long as the properties are not impaired.
Examples of the fine particles include fine particles having a refractive index different from that of the compound constituting the adhesive, conductive fine particles for improving antistatic performance without impairing transparency, and fine particles for improving wear resistance. Specifically, fine silica, fine alumina, ITO (Indium Tin Oxide) fine particles, silver fine particles, various synthetic resin fine particles and the like can be mentioned.

The surface modifier is not particularly limited as long as it has good compatibility with the adhesive and does not affect the curability of the adhesive or the optical performance after curing, and is an ionic or nonionic water-soluble interface. Activators, oil-soluble surfactants, polymer surfactants, fluorosurfactants, organometallic surfactants such as silicone, reactive surfactants, and the like can be used. In particular, fluorine-based surfactants such as perfluoroalkyl compounds and perfluoropolyether compounds, and organometallic surfactants such as silicone are particularly desirable because they have a large surface modification effect. The addition amount of the surface modifier is desirably in the range of 0.01 to 10% by mass with respect to the adhesive, more desirably 0.05 to 5% by mass, and further desirably 0.1 to 3% by mass. If the amount added is less than this range, the effect of addition becomes insufficient. On the other hand, if the amount added is too large, there is a risk of adverse effects such as an excessive decrease in adhesive strength. In addition, a surface modifier may be used independently and may use multiple types together as needed.
Furthermore, you may mix | blend various additives, such as antioxidant and a ultraviolet absorber, in the range which does not impair the effect of this invention.

  The polarizing element that can be used in the present invention is not particularly limited, and various types can be used. Examples of polarizing elements include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films, and two colors such as iodine and dichroic dyes. And polyene-based oriented films such as a product obtained by adsorbing a reactive substance and a dehydrochlorinated product of polyvinyl chloride. Among these, those obtained by stretching a polyvinyl alcohol film and adsorbing and orienting a dichroic material (iodine, dye) are preferably used. The thickness of the polarizing element is not particularly limited, but is generally about 5 to 50 μm.

  A polarizing element in which a polyvinyl alcohol film is dyed with iodine and uniaxially stretched can be produced by, for example, dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution of boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As the translucent protective film provided on one surface of the polarizing element, an optically isotropic film is preferable. For example, triacetyl such as Fujitac (product of Fuji Photo Film) or Konicatak (product of Konica Minolta Opto). Cycloolefin polymers such as cellulose (TAC) film, arton film (product of JSR), ZEONOR film, ZEONEX film (product of ZEON CORPORATION), TPX film (product of Mitsui Chemicals), acrylene film (product of Mitsubishi Rayon) ) And the like, but triacetyl cellulose and cycloolefin polymers are preferred from the viewpoint of flatness, heat resistance and moisture resistance when an elliptically polarizing plate is used. In general, the thickness of the translucent protective film is preferably 1 to 100 μm, particularly preferably 5 to 50 μm.

As the light-transmitting protective film, a film having a hard coat layer, antireflection treatment, anti-sticking, light diffusion or antiglare treatment on the surface can be used.
The hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate. For example, the protective film is applied with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the protective film by an appropriate method such as a blending method of transparent particles. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle size of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, and the like are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a light diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.
The antireflection layer, anti-sticking layer, light diffusion layer, antiglare layer, etc. can be provided on the translucent protective film itself, and separately from the translucent protective film layer as a separate optical layer. It can also be provided.

Next, the manufacturing method of the elliptically polarizing plate of this invention is demonstrated in detail.
The layer structure of the elliptically polarizing plate obtained in the present invention is selected from the following two types as shown in FIGS.
(I) Translucent protective film / adhesive layer 1 / polarizing element / adhesive layer 2 / optical anisotropic element (II) Translucent protective film / adhesive layer 1 / polarizing element / optical anisotropic element

Although it does not specifically limit as a manufacturing method of an elliptically polarizing plate, It can manufacture with the following method as an example.
First, the manufacturing method of structure (I) is demonstrated.
Configuration (I) is
(1) First step of obtaining a laminate (A) comprising a translucent protective film / adhesive layer 1 / polarizing element by adhering the translucent protective film to the polarizing element via the adhesive layer 1;
(2) An optical anisotropy in which a layer made of a liquid crystalline composition exhibiting at least positive uniaxiality is formed on an alignment substrate subjected to rubbing treatment, the layer is twisted nematically aligned, and the alignment is fixed A second step of forming an element to obtain a laminate (B) comprising an alignment substrate / optically anisotropic element;
(3) After the optically anisotropic element side of the laminate (B) is adhered to the polarizing element side of the laminate (A) via the adhesive layer 2, the alignment substrate is peeled off to optically anisotropic. A third step of transferring the element to the laminate (A) and obtaining an elliptically polarizing plate comprising a translucent protective film / adhesive layer 1 / polarizing element / adhesive layer 2 / optically anisotropic element;
It is characterized by passing through each process of at least.

Hereinafter, the manufacturing method from the 1st process to the 3rd process is explained in order.
First, the manufacturing method of the laminated body (A) which is a 1st process is demonstrated.
An adhesive layer 1 is formed on the polarizing element, and the light-transmitting protective film and the polarizing element are brought into close contact with each other via the adhesive layer 1, and then the adhesive layer is reacted (cured) as necessary. Thus, a laminate (A) bonded on the translucent protective film via the adhesive layer 1 can be obtained.

Subsequently, the manufacturing method of the laminated body (B) which is a 2nd process is demonstrated.
After rubbing the alignment substrate with a cloth or the like, a coating film of a liquid crystalline composition exhibiting at least positive uniaxiality is formed by an appropriate method, the solvent is removed as necessary, and the liquid crystal is heated by heating or the like. The twisted nematic alignment of the liquid crystalline composition is completed, and the alignment of the liquid crystalline composition is fixed by means suitable for the liquid crystalline composition used. Thus, a laminate (B) having a twisted nematic alignment liquid crystal layer on the alignment substrate can be obtained.

Next, the manufacturing method in the third step will be described.
After the twisted nematic alignment liquid crystal layer (optical anisotropic element) side of the laminate (B) is in close contact with the polarizing element side of the laminate (A) via the adhesive layer 2, an adhesive layer is optionally provided. After the reaction (curing), the alignment substrate is peeled off, and the optical anisotropic element is transferred to the laminate (A).
Thus, the elliptically polarizing plate of the present invention consisting of a translucent protective film / adhesive layer 1 / polarizing element / adhesive layer 2 / optically anisotropic element can be obtained.

When transferring the twisted nematic alignment liquid crystal layer to the laminate (A) of the laminate (B), if necessary, the twist nematic alignment liquid crystal layer is transferred to another substrate different from the alignment substrate, and then the laminate (A ) May be retransferred to.
In order to protect the surface of the optically anisotropic element layer of the obtained elliptically polarizing plate, a translucent overcoat layer may be provided or a temporary surface protective film may be bonded. Here, the translucent overcoat can also be selected from the aforementioned adhesives.

Next, a manufacturing method of the configuration (II) will be described.
Configuration (II) is
(1) First step of obtaining a laminate (A) comprising a translucent protective film / adhesive layer 1 / polarizing element by adhering the translucent protective film to the polarizing element via the adhesive layer 1;
(2) A rubbing treatment is performed on the polarizing element of the laminate (A) to form a layer made of a liquid crystalline composition exhibiting at least positive uniaxiality, and the layer is twisted nematically aligned. A second step of forming an optically anisotropic element fixed to obtain an elliptically polarizing plate comprising a translucent protective film / adhesive layer 1 / polarizing element / optically anisotropic element;
It is characterized by passing through each process of at least.

Hereinafter, the manufacturing method from the first step to the second step will be described in order.
First, the manufacturing method of the laminated body (A) which is a 1st process is the same as that of a structure (I).
The manufacturing method in the second step will be described.
A rubbing treatment is performed on the polarizing element of the laminate (A) produced in the first step, and a coating film of a liquid crystalline composition exhibiting at least positive uniaxiality is formed by an appropriate method, and a solvent or the like is added as necessary. The twisted nematic alignment of the liquid crystalline composition is completed by heating and the like, and the alignment of the liquid crystalline composition is fixed by means suitable for the liquid crystal physical composition used. Thus, a translucent protective film / adhesive layer 1 / polarizing element / optically anisotropic element comprising an optically anisotropic element comprising a twisted nematic alignment liquid crystal layer in which the liquid crystal orientation is fixed on the laminate (A). Can be obtained.

In order to protect the surface of the optically anisotropic element layer of the obtained elliptically polarizing plate, a translucent overcoat layer may be provided or a temporary surface protective film may be bonded. Here, the translucent overcoat can also be selected from the aforementioned adhesives.
In the second step of the configuration (II), depending on the orientation of the polarizing element with respect to the liquid crystalline composition, a rubbing may be performed after providing an appropriate alignment film that nematically aligns the liquid crystalline composition. The method of forming a layer of a liquid crystalline composition by applying the method is also included in the present invention (FIG. 3).
In the present invention, it is also possible to laminate a plurality of optical anisotropic element layers by repeatedly laminating optical anisotropic element layers on an alignment substrate via an adhesive layer or an adhesive layer.

The translucent protective film and polarizing element used for the production of the laminate (A) are preferably subjected to surface treatment.
For the surface treatment, a method suitable for a light-transmitting protective film or a polarizing element may be used. Examples of the method include saponification treatment, corona discharge treatment, flame treatment, low-pressure UV irradiation, plasma treatment and the like. More preferably, as the translucent protective film, for example, saponification treatment is preferable when triacetyl cellulose is used, and corona discharge treatment is preferable when a cycloolefin polymer is used.

The saponification treatment is performed by contacting with an alkaline aqueous solution, which is a normal method. As the alkaline aqueous solution, potassium hydroxide, sodium hydroxide or the like is used, and the alkali concentration is about 0.1 to 10% by mass, preferably about 0.5 to 5% by mass, more preferably about 1 to 3% by mass. A dilute solution of about% is sufficient. As treatment conditions, mild conditions of 1 to 60 minutes at room temperature, preferably 30 minutes or less, more preferably 15 minutes or less are sufficient. Needless to say, it is necessary to thoroughly wash with water after the treatment.
Similar to the above saponification treatment, the corona discharge treatment may be performed under ordinary conditions, for example, on the isotropic substrate surface in contact with the pressure-sensitive adhesive layer. The processing conditions vary depending on the type of substrate and corona processing apparatus to be used. For example, the energy density is preferably 1 to 300 W · min / m ² . The surface tension is increased by performing the corona discharge treatment, but it is desirable to increase the surface tension to 40 dyn / cm or more.

  The adhesive / adhesive layer may be formed in the same manner as the liquid crystalline composition layer, and the adhesive / adhesive layer is formed on an appropriate substrate provided with an easy release treatment such as silicone. A so-called non-carrier adhesive / adhesive may be used. Bonding between an optically anisotropic element and a polarizing element is performed by using a laminator, roll, pressurizer, etc. to improve the bonding strength, to prevent the generation of bubbles due to residual air at the bonding interface, etc. Pressure, heating or the like may be applied.

The optically anisotropic element, the polarizing element and the translucent protective film can be laminated in a continuous manner in the state of being aligned in the MD direction in the form of a long film when bonded.
Further, in addition to the manufacturing method, these three members can apply an optical anisotropic element and a light-transmitting protection to the polarizing element even if the optical anisotropic element and the light-transmitting protective film are simultaneously bonded to both sides of the polarizing element. You may bond in the order of a film, or the order of a translucent protective film and an optically anisotropic element.

  The total thickness of the elliptically polarizing plate of the present invention thus obtained varies depending on the thickness of the translucent protective film, polarizing element, adhesive, optical anisotropic element, etc. used, but is 150 μm or less, preferably 100 μm or less. Good. If the total thickness exceeds 150 μm, the roll diameter becomes too large when a long film is wound around the roll for a predetermined length, making it difficult to store in a conventional transport packaging container, or long if it can be stored in a conventional transport container. It is not preferable because the length becomes shorter.

Further, an elliptically polarizing plate in which at least one optical film is further laminated on the elliptically polarizing plate of the present invention may be used.
Although it will not restrict | limit especially if it is excellent in transparency and uniformity as an optical film, The liquid crystalline film which consists of a polymer stretched film and a liquid crystal can be used preferably. Examples of the stretched polymer film include a uniaxial or biaxial retardation film composed of a cellulose-based, polycarbonate-based, polyarylate-based, polysulfone-based, polyacryl-based, polyethersulfone-based, cyclic olefin-based polymer, or the like. Can do. Of these, polycarbonate and cyclic olefin polymers are preferred from the viewpoint of cost and film uniformity.

In addition, the liquid crystalline film made of liquid crystal here is not particularly limited as long as it is a film that can utilize the optical anisotropy generated from the alignment state by aligning the liquid crystal. For example, known materials such as various optical functional films using nematic liquid crystal, discotic liquid crystal, smectic liquid crystal and the like can be used.
The molecular alignment structure of the liquid crystalline film may be any of the molecular alignment structures such as smectic, nematic, twisted nematic, and cholesteric, and is in a homogeneous alignment and homeotropic alignment near the alignment substrate and near the air interface, respectively. The so-called hybrid orientation in which the average director of the conductive polymer is inclined from the normal direction of the film may be used.
The optical film exemplified here may be used alone or in a plurality of sheets in constituting a liquid crystal display device. Moreover, both a polymer stretched film and a liquid crystalline film can be used.

Hereinafter, a liquid crystal display device to which the elliptically polarizing plate of the present invention is applied will be described.
The liquid crystal display device of the present invention has at least the elliptically polarizing plate. When the elliptically polarizing plate of the present invention is disposed in a liquid crystal cell, it is necessary to dispose the optically anisotropic element side of the elliptically polarizing plate on the liquid crystal cell side.
A liquid crystal display device is generally composed of a polarizing plate, a liquid crystal cell, and a member such as a retardation compensation plate, a reflection layer, a light diffusion layer, a backlight, a front light, a light control film, a light guide plate, and a prism sheet as necessary. Although comprised, in this invention, there is no restriction | limiting in particular except the point which uses the said elliptically polarizing plate. Further, the use position of the elliptically polarizing plate is not particularly limited, and may be one place or a plurality of places.

The polarizing plate used for the liquid crystal display device is not particularly limited, and those obtained from the same polarizing element as those used for the elliptically polarizing plate described above can be used.
The liquid crystal cell is not particularly limited, and a general liquid crystal cell such as a liquid crystal layer sandwiched between a pair of transparent substrates provided with electrodes can be used.
The transparent substrate constituting the liquid crystal cell is not particularly limited as long as the liquid crystal material constituting the liquid crystal layer is aligned in a specific alignment direction. Specifically, a transparent substrate in which the substrate itself has a property of orienting liquid crystals, a transparent substrate in which an alignment film having the property of orienting liquid crystals is provided, but the substrate itself lacks the alignment ability. Either can be used. Moreover, a well-known thing can be used for the electrode of a liquid crystal cell. Usually, it can be provided on the surface of the transparent substrate in contact with the liquid crystal layer, and when a substrate having an alignment film is used, it can be provided between the substrate and the alignment film.
The material exhibiting liquid crystallinity for forming the liquid crystal layer is not particularly limited, and examples thereof include various ordinary low-molecular liquid crystal substances, high-molecular liquid crystal substances, and mixtures thereof that can constitute various liquid crystal cells. In addition, a dye, a chiral agent, a non-liquid crystal substance, or the like can be added to these as long as liquid crystallinity is not impaired.

In addition to the electrode substrate and the liquid crystal layer, the liquid crystal cell may include various components necessary to form various types of liquid crystal cells described later.
As liquid crystal cell methods, TN (Twisted Nematic) method, STN (Super Twisted Nematic) method, ECB (Electrically Controlled Birefringence) method, IPS (In-Plane Switching) method, VA (Vertical Alignment) method, OCB (Optically Compensated) Birefringence method, HAN (Hybrid Aligned Nematic) method, ASM (Axially Symmetric Aligned Microcell) method, halftone gray scale method, domain division method, display method using ferroelectric liquid crystal, anti-ferroelectric liquid crystal, etc. The method is mentioned.
Further, the driving method of the liquid crystal cell is not particularly limited, and a passive matrix method used for STN-LCD and the like, and an active matrix method using active electrodes such as TFT (Thin Film Transistor) electrodes and TFD (Thin Film Diode) electrodes, Any driving method such as a plasma addressing method may be used.

When the elliptically polarizing plate of the present invention is applied to a liquid crystal display device, as viewed from the observer, even if the elliptically polarizing plate is closer to the observer side (front side) than the liquid crystal cell of the liquid crystal display device, It may be on the opposite side (rear) or on both sides of the liquid crystal cell.
The retardation compensator can be appropriately selected from the optical films used in the present invention and can be used alone or in combination. Moreover, both a polymer stretched film and an optical compensation film made of liquid crystal can be used.

  The reflective layer is not particularly limited, and metals such as aluminum, silver, gold, chromium and platinum, alloys containing them, oxides such as magnesium oxide, dielectric multilayer films, liquid crystals exhibiting selective reflection, or combinations thereof Etc. can be illustrated. These reflective layers may be flat or curved. In addition, the reflective layer is processed to have a surface shape such as a concavo-convex shape so as to have diffuse reflectivity, the liquid crystal cell is combined with an electrode on the electrode substrate opposite to the observer side, and the thickness of the reflective layer It may be a semi-transmissive reflective layer in which light is partially transmitted by thinning or forming a hole or the like, or a combination thereof.

The light diffusion layer is not particularly limited as long as it has a property of diffusing incident light isotropically or anisotropically. For example, it may be composed of two or more regions, with a difference in refractive index between the regions, or with surface irregularities. Examples of the two or more regions having a refractive index difference between the regions include those in which particles having a refractive index different from that of the matrix are dispersed in the matrix. The light diffusing layer itself may have adhesiveness.
The film thickness of the light diffusing layer is not particularly limited, but is usually preferably 10 μm or more and 500 μm or less.
Further, the total light transmittance of the light diffusion layer is preferably 50% or more, and particularly preferably 70% or more. Furthermore, the haze value of the light diffusion layer is usually 10 to 95%, preferably 40 to 90%, and more preferably 60 to 90%.
The backlight, the front light, the light control film, the light guide plate, and the prism sheet are not particularly limited, and known ones can be used.

  The liquid crystal display device of the present invention can be provided with other constituent members in addition to the constituent members described above. For example, by attaching a color filter to the liquid crystal display device of the present invention, a color liquid crystal display device capable of performing multicolor or full color display with high color purity can be manufactured.

Next, an organic electroluminescence display device (organic EL display device) to which the elliptically polarizing plate of the present invention is applied will be described.
Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. It has been.

In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.
In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.
In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .
That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wavelength plate and the angle formed by the polarization direction of the polarizing plate and the phase difference plate is π / 4. .
This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.
When the elliptically polarizing plate of the present invention is applied to an organic EL display device, as described above, in order to prevent reflection of external light, the observer side (front side) arrangement of the organic EL display device is viewed from the observer. Better to do.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
In addition, each analysis method used in the Example is as follows. In this embodiment, optical parameters such as Δn · d are values at a wavelength of 550 nm unless otherwise specified.

(1) Measurement of logarithmic viscosity Using an Ubbelohde viscometer, it was measured at 30 ° C. in a phenol / tetrachloroethane (60/40 mass ratio) mixed solvent.
(2) Microscope observation The alignment state of the liquid crystal was observed with an Olympus BH2 polarizing microscope.
(3) Ellipsometry measurement of liquid crystal composition layer Ellipsometer (DVA-36VWLD) manufactured by Mizoji Optical Industry Co., Ltd. was used.
(4) Measurement of Δnd and twist angle of liquid crystal composition layer RETS-100 manufactured by Otsuka Electronics Co., Ltd. was used.
(5) Measurement of film thickness SURFACE TEXTURE ANALYSIS SYSTEM Dektak 3030ST manufactured by SLOAN was used. In addition, a method of obtaining the film thickness from interference wave measurement (UV-visible / near-infrared spectrophotometer V-570 manufactured by JASCO Corporation) and refractive index data was also used.

<Example 1>
(Preparation of laminate A)
A TAC film (40 μm, manufactured by Fuji Photo Film Co., Ltd.) was immersed in a 2% by mass aqueous potassium hydroxide solution at room temperature for 5 minutes for saponification treatment, washed in running water, and dried. A saponified TAC film was bonded to one surface of a polarizing element in which iodine was adsorbed to stretched polyvinyl alcohol, using an acrylic adhesive as the adhesive layer 1, and a laminate A was produced. The total film thickness was about 65 μm, which was thinner than the normal one (105 μm).

(Preparation of liquid crystalline composition solution B and laminate D)
Polymerization was carried out at 270 ° C. for 12 hours in a nitrogen atmosphere using 50 mmol of terephthalic acid, 50 mmol of 2,6-naphthalenedicarboxylic acid, 40 mmol of methylhydroquinone diacetate, 60 mmol of catechol diacetate, and 60 mg of N-methylimidazole. The obtained reaction product was dissolved in tetrachloroethane and then purified by reprecipitation with methanol to obtain 14.7 g of a liquid crystalline polyester (polymer 1). This liquid crystalline polyester had a logarithmic viscosity of 0.17 (dl / g), a nematic phase as a liquid crystal phase, an isotropic phase-liquid crystal phase transition temperature of 250 ° C. or higher, and a glass transition point of 115 ° C.
Next, 90 mmol of biphenyl dicarbonyl chloride, 10 mmol of terephthaloyl chloride and 105 mmol of S-2-methyl-1,4-butanediol were reacted in dichloromethane at room temperature for 20 hours, and the reaction solution was poured into methanol for reprecipitation. As a result, 12.0 g of liquid crystalline polyester (polymer 2) was obtained. The logarithmic viscosity of Polymer 2 was 0.12 (dl / g).
An 8% by mass γ-butyrolactone solution of a liquid crystalline composition containing a mixed polymer composed of 19.82 g of polymer 1 and 0.18 g of polymer 2 was prepared as liquid crystalline composition solution B.

While conveying a long PEEK film with a width of 650 mm and a thickness of 100 μm, a 150 mmφ rubbing roll wrapped with a rayon cloth is set obliquely and rotated at a high speed to perform continuous rubbing and an orientation with a rubbing angle of 25 ° A substrate film was obtained. Here, the rubbing angle is an angle in the counterclockwise direction from the MD direction when the rubbing surface is viewed from above. The liquid crystal composition solution B is continuously applied and dried on the alignment substrate film using a die coater, and then heat-treated at 150 ° C. for 10 minutes to align the liquid crystal raw composition, and then at room temperature. The alignment was fixed by cooling to obtain a laminate D of a liquid crystalline composition layer (optical anisotropic element) and a PEEK film.
The thickness of the liquid crystalline composition layer of the obtained laminate D was 4 μm.

Since the PEEK film used as the alignment substrate has a large birefringence, it is difficult to measure the optical parameters of the liquid crystalline composition layer in the form of the laminate D. Therefore, on the triacetyl cellulose (TAC) film as follows. The liquid crystal composition layer was transferred.
That is, on the liquid crystal composition layer on the PEEK film, an ultraviolet curable adhesive was applied to a thickness of 5 μm, laminated with a TAC film (40 μm thickness, manufactured by Fuji Photo Film Co., Ltd.), and from the TAC film side. The adhesive was cured by irradiating ultraviolet rays, and then the PEEK film was peeled off to obtain a laminate composed of a liquid crystalline composition layer / adhesive layer / TAC film. The obtained laminate was subjected to parameter measurement using RETS-100 manufactured by Otsuka Electronics Co., Ltd. As a result, it was twisted nematically oriented, the twist angle was −240 degrees, and Δn · d was 800 nm.

(Preparation of elliptically polarizing plate E)
A commercially available UV curable adhesive (UV-3400, manufactured by Toagosei Co., Ltd.) was applied as an adhesive layer 2 to a thickness of 5 μm on the optically anisotropic element of the laminate D, and the produced laminate was formed thereon. The polarizing element side of the body A was laminated, and the adhesive layer 2 was cured by UV irradiation of about 600 mJ. Thereafter, the PEEK film is peeled off from the laminate in which the PEEK film / optically anisotropic element / adhesive layer 2 / polarizing element / adhesive layer 1 / TAC film is integrated, whereby the optical anisotropic element is placed on the laminate A. And an elliptically polarizing plate E composed of TAC film / adhesive layer 1 / polarizing element / adhesive layer 2 / optically anisotropic element was obtained. The total thickness of the elliptically polarizing plate E was 75 μm.
When this elliptically polarizing plate E was optically inspected, no damage such as spots or scratches was found. When the optically anisotropic element side of the elliptically polarizing plate E is attached to a glass plate via an acrylic adhesive, it is placed in a constant temperature and humidity chamber at 60 ° C. and 90% RH, taken out after 500 hours, and observed. No abnormalities such as bubbles were observed.

<Example 2>
(Preparation of adhesive)
As an urethane-based adhesive, Toyo Morton Co., Ltd., an isocyanate-based curing agent, is added to 100 parts of “EL-436A” (aqueous solution with a solid content of 35%) manufactured by Toyo Morton Co., Ltd., which is a polyester polyol prepolymer as a main component. 30 parts of "EL-436B" (100% active ingredient) was added, and further diluted with water to a solid content concentration of 20%. On the other hand, as a polyvinyl alcohol-based adhesive, a carboxyl group-modified polyvinyl alcohol “Kuraray Poval KL318” manufactured by Kuraray Co., Ltd. (a saponified product of a copolymer having a molar ratio of vinyl acetate and sodium itaconate of about 98: 2, saponification degree) A 3% aqueous solution having a molecular weight of about 85,000 was prepared. The obtained urethane adhesive and polyvinyl alcohol aqueous solution were mixed at a mass ratio of 1: 1 (20: 3 in terms of solid content mass ratio) to obtain a mixed adhesive.

(Preparation of laminate F)
The mixed adhesive prepared as the adhesive layer 1 was applied within one minute after mixing on one surface of the polarizing element in which iodine was adsorbed to the stretched polyvinyl alcohol, and a ZEONOR film (film thickness) was applied to the one surface. 40 μm, manufactured by Nippon Zeon Co., Ltd.) was subjected to a corona treatment under the condition of 250 W · min / m ² , and laminated on the corona-treated surface within 30 seconds after the corona treatment to produce a laminate F. The total film thickness was about 65 μm, which was thinner than the normal one (105 μm).

(Preparation of elliptical polarizing plate G)
A commercially available UV curable adhesive (UV-3400, manufactured by Toagosei Co., Ltd.) was applied as an adhesive layer 2 to a thickness of 5 μm on the optically anisotropic element of the laminate D produced in Example 1. The polarizing element side of the laminate F was laminated thereon, and the adhesive layer 2 was cured by UV irradiation of about 600 mJ. Thereafter, the PEEK film is peeled off from the laminate in which the PEEK film / optically anisotropic element / adhesive layer 2 / polarizing element / adhesive 1 / Zeonor film is integrated, so that the optical anisotropic element is placed on the laminate F. Then, an elliptically polarizing plate G composed of ZEONOR film / adhesive layer 1 / polarizing element / adhesive layer 2 / optically anisotropic element was obtained. The total thickness of the elliptically polarizing plate G was 75 μm.
When this elliptically polarizing plate G was optically inspected, no damage such as spots or scratches was found. When the optically anisotropic element side of the elliptically polarizing plate G is attached to a glass plate via an acrylic adhesive, it is placed in a constant temperature and humidity chamber at 60 ° C. and 90% RH, and is taken out and observed after 500 hours. No abnormalities such as bubbles were observed.

<Example 3>
(Preparation of elliptical polarizing plate H)
The liquid crystal composition solution prepared by changing the mixing ratio of the polymer 1 and the polymer 2 synthesized in Example 1 was continuously applied to the polarizing element side of the laminate F produced in Example 2 using a die coater. After coating and drying, the liquid crystal composition was aligned by heat treatment at 150 ° C. for 10 minutes. Next, the film was cooled to room temperature to fix the orientation, and an elliptically polarizing plate H composed of ZEONOR film / adhesive layer 1 / polarizing element / optically anisotropic element was obtained. The total thickness of the elliptically polarizing plate H was 70 μm.
This optically anisotropic element layer was twisted nematically oriented, the twist angle was −65 degrees, and Δnd was 190 nm. When this ellipsoidal polarizing plate H was subjected to ellipsometry with an ellipsometer (DVA-36VWLD manufactured by Mizoji Optical Co., Ltd.), the ellipticity at a wavelength of 550 nm was 0.94, and it was a circularly polarizing plate having good circular polarization characteristics. It was confirmed that there was.
When this elliptical polarizing plate H was optically inspected, no damage such as spots or scratches was found. When the optically anisotropic element side of the elliptically polarizing plate H is attached to a glass plate via an acrylic adhesive, it is placed in a constant temperature and humidity chamber at 60 ° C. and 90% RH, and is taken out and observed after 500 hours. No abnormalities such as bubbles were observed.

<Example 4>
(Preparation of laminated body J)
While being transported onto the polarizing element of the laminate F produced in Example 2, a 5 mass% solution of alkyl-modified polyvinyl alcohol (PVA, manufactured by Kuraray Co., Ltd., PVA-117H) (the solvent is the mass of water and isopropyl alcohol). A mixed solvent having a ratio of 1: 1) is continuously applied and dried using a die coater, and heat-treated at 130 ° C. to obtain a laminate J composed of zeonore film / adhesive layer 1 / polarizing element / PVA alignment film. It was.

(Preparation of elliptical polarizing plate K)
The liquid crystal composition solution B prepared in Example 1 was continuously applied and dried on the PVA alignment film of the laminate J using a die coater, and then heat-treated at 150 ° C. for 10 minutes to obtain a liquid crystal composition. Were oriented. Next, the film was cooled to room temperature to fix the orientation, and an elliptically polarizing plate K composed of ZEONOR film / adhesive layer 1 / polarizing element / PVA alignment film / optically anisotropic element was obtained. The total thickness of the elliptically polarizing plate K was 73 μm.
When this elliptically polarizing plate K was optically inspected, no damage such as spots or scratches was found. When the optically anisotropic element side of the elliptically polarizing plate K is attached to a glass plate via an acrylic adhesive, it is placed in a constant temperature and humidity chamber at 60 ° C. and 90% RH, and is taken out and observed after 500 hours. No abnormalities such as bubbles were observed.

<Comparative Example 1>
(Preparation of laminate L)
The optically anisotropic element side of the laminate D produced in Example 1 was transferred to a triacetyl cellulose (TAC) film (40 μm) via an ultraviolet curable adhesive. That is, an adhesive is applied on the optical anisotropic element on the PEEK film so as to have a thickness of 5 μm, laminated with a TAC film, and irradiated with ultraviolet rays from the TAC film side to cure the adhesive, and then PEEK. The film was peeled off to obtain a laminate L (optical anisotropic element / adhesive layer / TAC film).
(Preparation of elliptical polarizing plate N)
A polarizing plate M was prepared by attaching a saponified TAC film to both sides of a polarizing element in which iodine was adsorbed to stretched polyvinyl alcohol using an acrylic adhesive.
The optically anisotropic element side of the laminate L was bonded to the polarizing plate M via an acrylic pressure-sensitive adhesive to produce an elliptical polarizing plate N. Since this elliptically polarizing plate N is as thick as about 200 μm and the winding thickness becomes large, the processing length in one operation must be shorter than the preparation of the elliptically polarizing plates of Examples 1 to 4. It was.
An acrylic pressure-sensitive adhesive was applied to the TAC film on the optically anisotropic element side of the elliptically polarizing plate N and attached to a glass plate, and the same test as in Example 1 was performed. Peeling was observed.

<Example 5>
Using the elliptically polarizing plate E obtained in Example 1, an STN-type transmissive liquid crystal display device was produced with the arrangement shown in FIG. Here, in this example, the device was manufactured by performing an experiment in which the counterclockwise direction from the polarizing element 4 side toward the liquid crystal cell 8 side is set to + and the clockwise direction is set to −. It is first added that the same result can be obtained even if a similar experiment is performed with the clockwise direction toward the cell 8 as + and the counterclockwise direction as −.
FIG. 5 shows the relationship between the angles θ1 to θ5 in each constituent member of the STN type transflective liquid crystal display device.
In FIG. 5, the alignment direction 81 on the surface on the elliptical polarizing plate 1 side of the liquid crystal layer in the liquid crystal cell 8 and the alignment direction 82 on the surface on the polarizing plate 9 side form an angle θ1. The orientation axis direction 61 on the surface of the optically anisotropic element 6 on the polarizing element 4 side and the orientation axis direction 62 on the surface on the liquid crystal cell 8 side form an angle θ2. Further, the absorption axis 41 of the polarizing element 4 and the orientation axis direction 61 on the surface of the optical anisotropic element 6 on the polarizing element 4 side form an angle θ3, and the absorption axis 41 of the polarizing element 4 and the liquid crystal cell 8 The liquid crystal layer forms an angle θ4 with the alignment direction 81 on the surface on the polarizing element 4 side. The absorption axis 91 of the polarizing plate 9 forms an angle θ5 with the absorption axis 41 of the polarizing element 4.

ZLI-2293 was used as the liquid crystal material and twisted to θ1 = + 240 degrees. The product Δnd of the refractive index anisotropy Δn of the liquid crystal substance in the liquid crystal cell 8 and the thickness d of the liquid crystal layer was about 830 nm.
The optical anisotropic element 6 was produced by the same method as the optical anisotropic element of Example 1. The optical anisotropic element 6 had an Δnd of approximately 800 nm and a twist angle of θ2 = −240 degrees. At this time, the angle θ3 = + 45 degrees from the absorption axis 41 of the polarizing element 4 to the orientation axis 61 on the surface of the optical anisotropic element 6 on the polarizing plate side, the polarizing axis side of the liquid crystal layer 8 from the absorption axis 41 of the polarizing element 4 The angle θ4 with respect to the orientation direction 81 on the surface is set to +135 degrees.
A polarizing plate 9 (thickness: about 100 μm; SQW-062 manufactured by Sumitomo Chemical Co., Ltd.) was disposed on the backlight 10 surface side (lower side of the figure) of the liquid crystal cell 8. The angle θ5 from the absorption axis 41 of the polarizing element 4 to the absorption axis 91 of the polarizing plate 9 was set to +90 degrees.
A normal transparent adhesive layer was disposed between the elliptically polarizing plate 1 and the liquid crystal cell 8 and the polarizing plate 9.
A driving voltage is applied to the above liquid crystal display device from a driving circuit (not shown) (driven at 1/240 duty and optimum bias), and a backlight 10 is arranged to examine optical characteristics during lighting (transmission mode). As a result, a bright and high-contrast display was obtained. It has been found that the viewing angle characteristic is particularly good in the transmission mode.

<Example 6>
The elliptically polarizing plate H produced in Example 3 was attached as the elliptically polarizing plate 1 defined in FIG. 6 on the transparent glass substrate 12 of the organic EL element of the commercially available organic EL display 11 via an acrylic adhesive. An organic EL display device was prepared. As a result, it was found that an organic EL display device exhibiting a significant effect of preventing external light reflection and having excellent visibility as compared with the case where the elliptically polarizing plate of the present invention is not disposed can be obtained.

It is an elevation sectional view showing typically the example of composition of the elliptically polarizing plate of the present invention. It is an elevation sectional view showing typically another example of composition of the elliptically polarizing plate of the present invention. It is an elevation sectional view showing typically another example of composition of the elliptically polarizing plate of the present invention. 6 is a conceptual diagram of a liquid crystal display used in Example 4. FIG. FIG. 10 is a plan view illustrating an absorption axis of a polarizing plate, a liquid crystal cell, and an axial angle relationship of an optically anisotropic layer in the liquid crystal display device of Example 4. 10 is a conceptual diagram of an organic EL display used in Example 5. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elliptical polarizing plate 2 Translucent protective film 3 Adhesive layer 1
4 Polarizing element 5 Adhesive layer 2
6 Optical anisotropic element 7 Alignment film 8 Liquid crystal cell 9 Polarizing plate 10 Back light 41 Absorption axis of polarizing element 4 on the viewer side 61 Orientation axis on the polarizing element 4 side of optical anisotropic element 6 62 of optical anisotropic layer 6 Alignment axis on the liquid crystal cell 8 side 81 Alignment direction on the surface of the liquid crystal layer in the liquid crystal cell 8 on the polarizing element 4 side 82 Alignment direction on the surface on the backlight 10 side of the liquid crystal layer in the liquid crystal layer 8 91 Absorption axis of the polarizing plate 9 11 Organic EL device
12 Transparent glass substrate 13 Anode 14 Light emitting layer 15 Cathode

Claims (19)

  A translucent protective film, a polarizing element and an optically anisotropic element are elliptically polarizing plates laminated in this order, and the liquid crystalline composition in which the optically anisotropic element exhibits at least positive uniaxiality in a liquid crystal state An elliptically polarizing plate comprising a twisted nematic alignment liquid crystal layer in which the alignment is fixed after twisted nematic alignment.   The elliptically polarizing plate according to claim 1, wherein the translucent protective film, the polarizing element and the optical anisotropic element are in the form of a long film.   The twist angle θ of the twisted nematic alignment liquid crystal layer is in the range of 5 ° to 400 °, and the product (Δn · d) of the refractive index anisotropy Δn of the twisted nematic alignment liquid crystal layer and the thickness d of the liquid crystal layer is 50 nm to The elliptically polarizing plate according to claim 1, wherein the elliptically polarizing plate has a range of 1500 nm.   4. The elliptically polarizing plate according to claim 1, wherein the translucent protective film is triacetyl cellulose.   The elliptically polarizing plate according to claim 1, wherein the translucent protective film is a cycloolefin polymer.   The elliptically polarizing plate according to claim 1, wherein the elliptically polarizing plate has a thickness of 150 μm or less.   The elliptically polarizing plate according to claim 1, wherein an alignment film in which the liquid crystalline composition forms a nematic alignment is provided between the polarizing element and the optical anisotropic element.   The elliptically polarizing plate according to claim 1, wherein a translucent overcoat layer is provided on a surface of the optically anisotropic element opposite to the polarizing element.   The elliptically polarizing plate according to claim 8, wherein the translucent overcoat layer is made of an acrylic resin.   The elliptically polarizing plate according to any one of claims 1 to 9, wherein the alignment direction of the liquid crystal molecules in the vicinity of either one of the both-side interfaces of the twisted nematic alignment liquid crystal layer is not parallel to the MD direction.   An elliptically polarizing plate, wherein at least one optical film is further laminated on the elliptically polarizing plate according to claim 1. (1) First step of obtaining a laminate (A) comprising a translucent protective film / adhesive layer 1 / polarizing element by adhering the translucent protective film to the polarizing element via the adhesive layer 1;
(2) An optical anisotropy in which a layer made of a liquid crystalline composition exhibiting at least positive uniaxiality is formed on an alignment substrate subjected to rubbing treatment, the layer is twisted nematically aligned, and the alignment is fixed A second step of forming an element to obtain a laminate (B) comprising an alignment substrate / optically anisotropic element;
(3) After the optically anisotropic element side of the laminate (B) is adhered to the polarizing element side of the laminate (A) via the adhesive layer 2, the alignment substrate is peeled off to optically anisotropic. A third step of transferring the element to the laminate (A) and obtaining an elliptically polarizing plate comprising a translucent protective film / adhesive layer 1 / polarizing element / adhesive layer 2 / optically anisotropic element;
The manufacturing method of the elliptically polarizing plate characterized by passing through each process of these. (1) First step of obtaining a laminate (A) comprising a translucent protective film / adhesive layer 1 / polarizing element by adhering the translucent protective film to the polarizing element via the adhesive layer 1;
(2) The polarizing element surface of the laminate (A) is rubbed to form a layer made of a liquid crystalline composition exhibiting at least positive uniaxiality, and the layer is twisted nematically aligned. A second step of forming an optically anisotropic element fixed to obtain an elliptically polarizing plate comprising a translucent protective film / adhesive layer 1 / polarizing element / optically anisotropic element;
The manufacturing method of the elliptically polarizing plate characterized by passing through each process of these.   14. The elliptically polarizing plate according to claim 13, wherein a rubbing treatment is performed after providing an alignment film on which a liquid crystalline composition exhibiting at least positive uniaxiality forms a nematic alignment on the polarizing element. Manufacturing method.   The method for producing an elliptically polarizing plate according to claim 12 or 13, wherein the translucent protective film is triacetyl cellulose or a cycloolefin-based polymer.   The method for producing an elliptically polarizing plate according to claim 12 or 13, wherein the translucent protective film is surface-treated.   The method for producing an elliptically polarizing plate according to claim 12 or 13, wherein the surface treatment is a saponification treatment or a corona discharge treatment.   The liquid crystal display device which has arrange | positioned the elliptically polarizing plate in any one of Claims 1-11 in the surface of the at least one side of a liquid crystal cell.   An electroluminescent display device comprising the elliptically polarizing plate according to claim 1.

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