WO2019182121A1 - Electroluminescent display device - Google Patents

Abstract

An electroluminescent display device comprising an electroluminescent cell and a circular polarization plate that is positioned further toward a viewing side than the electroluminescent cell, wherein the circular polarization plate has, in order, a phase difference layer, a polarizer, and a substrate film, (1) the in-plane retardation of the substrate film is 3000-30000nm, (2) no self-supporting film is present between the polarizer and the phase difference layer, or only one self-supporting film is present (here, "between the polarizer and the phase difference layer" includes the phase difference layer), and (3) the phase difference layer has a 1/2 wavelength layer and a 1/4 wavelength layer.

Description

Electroluminescence display device

The present invention relates to an electroluminescence (EL) display device.

In the EL display device, there is a problem that extraneous light is reflected by the surface of a constituent material such as an image display cell and a touch sensor, these wiring portions, etc., and visibility is lowered. In order to solve these problems, a method has been proposed in which an optical layered body is disposed on the exit surface of an image display device to reduce reflection of extraneous light. In general, a circularly polarizing plate in which a linearly polarizing plate and a quarter-wave retardation plate are stacked is used for this optical laminate.

A polyester film having an in-plane retardation of 3000 to 30000 nm has been proposed as a polarizer protective film for polarizing plates (see, for example, Patent Document 1). Polyester film has lower moisture permeability, better mechanical properties (high impact resistance and higher elastic modulus), and better chemical properties (solvent resistance, etc.) than cellulose or acrylic films. Therefore, it is suitably used for an image display device. However, since the polyester film has birefringence, there is a drawback that rainbow unevenness is likely to occur. Therefore, in order to suppress rainbow unevenness and give sufficient in-plane retardation using a polyester film, the film needs to be thickened.
Furthermore, in order to suppress the influence of wavelength dispersion of the refractive index and obtain a circularly polarizing plate with better color reproducibility, a technique for combining a quarter wavelength plate and a half wavelength plate has been proposed (patent) Reference 2). However, when such a plurality of retardation plates are laminated on the polarizing plate, the above thickness problem becomes more prominent. In addition, since a plurality of films are laminated on the circularly polarizing plate, curling tends to occur when the circularly polarizing plate is wound and stored in the manufacturing process, and handling in the subsequent bonding process with the EL cell becomes difficult. There was a case. In particular, in a large-sized image display device exceeding 40 inches (the length of the diagonal line of the display section is 40 inches), the circularly polarizing plate becomes large, and the problem of curling is likely to occur.

Further, in recent years, as an image display device, a flexible EL that can be folded into a V-shape, Z-shape, W-shape, double doors, etc. or rolled up while being carried while having a wide display surface. Display devices have been proposed. When a circularly polarizing plate is used in such a foldable (foldable) or rollable (rollable) EL display device, sufficient bending performance cannot be obtained due to its thickness. When left in a hot place such as a film, there are problems such that the film is easily peeled off and bending marks are easily formed.

JP 2012-256057 A Japanese Patent Laid-Open No. 10-68816

The present invention has been made against the background of the problems of the prior art. That is, the object of the present invention is to reduce the thickness while ensuring visibility, to prevent trouble in the manufacturing process, and in the case of a flexible EL display device, it is left in a repeated bending or high temperature state. It is an object of the present invention to provide an EL display device in which laminated members are not easily peeled off and are not easily creased.

The present inventors can reduce the thickness while ensuring visibility, are less likely to cause trouble in the manufacturing process, and in the case of a flexible EL display device, when left in a repeated bending or high temperature state However, as a result of intensive investigations to develop an EL display device in which the laminated members are not easily peeled off and are not easily creased, a base film having a specific in-plane retardation is used, and a polarizer and a retardation layer are used. It has been found that the above object can be achieved by reducing the number of self-supporting films present to 1 or less and using a circularly polarizing plate having a ½ wavelength layer and a ¼ wavelength layer as a retardation plate. The present invention has been completed based on such findings.

That is, the present invention relates to the EL display device described in Items 1 to 4.
Item 1.
An electroluminescence display device comprising an electroluminescence cell, and a circularly polarizing plate disposed on the viewing side of the electroluminescence cell,
The circularly polarizing plate has, in order, a retardation layer, a polarizer, and a base film,
(1) The in-plane retardation of the base film is 3000 to 30000 nm,
(2) There is no self-supporting film between the polarizer and the retardation layer, or there is only one film (here, the retardation layer itself is included between the polarizer and the retardation layer), and (3) The electroluminescence display device in which the retardation layer has a ½ wavelength layer and a ¼ wavelength layer.
Item 2.
2. The electroluminescence display device according to item 1, wherein the polarizer has a thickness of 12 μm or less.
Item 3.
Item 3. The electroluminescent display device according to Item 1 or 2, wherein the polarizer comprises a polymerizable liquid crystal compound and a dichroic dye.
Item 4.
Item 4. The electroluminescence display device according to any one of Items 1 to 3, wherein at least one of the ½ wavelength layer and the ¼ wavelength layer is made of a liquid crystal compound.

The EL display device of the present invention uses a base film having an in-plane retardation of 3000 to 30000 nm, the number of self-supporting films existing between the polarizer and the retardation layer is 1 or less, and the retardation layer is 1 Since a circularly polarizing plate having a / 2 wavelength layer and a 1/4 wavelength layer is used, it is excellent in visibility (inhibition of rainbow unevenness), can be thinned, and troubles are unlikely to occur in the manufacturing process.
In addition, in the case of a flexible EL display device, even when the EL display device is repeatedly bent or left in a high temperature state, the stacked members are hardly peeled off and hardly creased.

The EL display device of the present invention includes an EL cell and a circularly polarizing plate disposed on the viewing side of the EL cell. By disposing the circularly polarizing plate on the viewing surface of the EL display device, it is possible to reduce the decrease in visibility due to the external light reflected from the surface of the EL cell or the wiring. The EL display device of the present invention is thin. The circularly polarizing plate has a retardation layer, a polarizer, and a base film in this order.

First, the circularly polarizing plate used in the present invention will be described. A circularly-polarizing plate has a phase difference layer, a polarizer, and a base film in order. In the circularly polarizing plate, the retardation layer, the polarizer, and the substrate film are basically laminated in this order, but it is a concept that includes the case where other layers exist between the respective layers.

A. Circularly polarizing plate Base film First, the base film of the circularly polarizing plate will be described. The circularly polarizing plate has a base film on the viewing side of the polarizer.
(Material of base film)
The resin for the base film used in the present invention can be used without particular limitation as long as it causes birefringence by orientation. From the viewpoint that retardation can be increased, polyester, polycarbonate, polystyrene and the like are preferable, and polyester is more preferable. Preferable polyester includes polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and among them, PET and PEN are more preferable. By using a polyester film as the substrate film, an EL display device having a circularly polarizing plate excellent in moisture permeation resistance, dimensional stability, mechanical strength, and chemical stability can be obtained.

In the case of PET, the intrinsic viscosity (IV) of the resin constituting the base film is preferably 0.58 to 1.5 dL / g. The lower limit of IV is more preferably 0.6 dL / g, still more preferably 0.65 dL / g, and particularly preferably 0.68 dL / g. The upper limit of IV is more preferably 1.2 dL / g, still more preferably 1 dL / g. If the IV of PET is less than 0.58 dL / g, there may be a case where bending marks are likely to be formed by repeated bending. When the IV of PET exceeds 1.5 dL / g, it may be difficult to produce a film. As the intrinsic viscosity (IV) in the present invention, a value obtained by mixing phenol and 1,1,2,2-tetrachloroethane at a mass ratio of 6: 4 as a solvent and measuring at a temperature of 30 ° C. is adopted. To do.

The base film preferably has a light transmittance of 380 nm at a wavelength of 20% or less. The light transmittance at a wavelength of 380 nm is more preferably 15% or less, further preferably 10% or less, and particularly preferably 5% or less. If the light transmittance is 20% or less, the alteration of iodine in the polarizer or dichroic dye due to ultraviolet rays can be suppressed. The transmittance in the present invention is measured in a direction perpendicular to the plane of the film, and can be measured using a spectrophotometer (for example, Hitachi U-3500 type).

Making the light transmittance at a wavelength of 380 nm of the base film 20% or less means adding an ultraviolet absorber in the base film, applying a coating solution containing the ultraviolet absorber to the base film surface, This can be achieved by appropriately adjusting the type or concentration of the ultraviolet absorber and the thickness of the base film. In the present invention, a substance known in the art can be used as the ultraviolet absorber. Examples of the ultraviolet absorber include an organic ultraviolet absorber and an inorganic ultraviolet absorber, and an organic ultraviolet absorber is preferable from the viewpoint of transparency.

The organic ultraviolet absorber can be used without particular limitation as long as the light transmittance of the base film at a wavelength of 380 nm can be reduced to 20% or less. Examples of such organic ultraviolet absorbers include benzotriazole, benzophenone, cyclic imino ester, and combinations thereof.

It is also preferable to add particles having an average particle diameter of 0.05 to 2 μm to the base film in order to improve slipperiness. As particles, inorganic particles such as titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, calcium fluoride; Examples thereof include organic polymer particles such as styrene, acrylic, melamine, benzoguanamine, and silicone. The average particle size was calculated by a method of observing particles on the cross section of the film with a scanning electron microscope. Specifically, 100 particles of the cross section of the film were observed with a scanning electron microscope, the diameter (d) of each particle was measured, and the average value thereof was taken as the average particle diameter.
These particles can be added to the entire substrate film. Alternatively, the substrate may be a skin-core coextruded multilayer structure and the particles may be added only to the skin layer.

(In-plane retardation of base film)
The base film has an in-plane retardation of 3000 to 30000 nm. One of the characteristics of the EL display device of the present invention is to use a circularly polarizing plate having an in-plane retardation of 3000 to 30000 nm. When the in-plane retardation of the substrate film is less than 3000 nm, good visibility may not be ensured when observed from an oblique direction with respect to the normal direction. In addition, when the purpose is to prevent blackout or coloring when viewing images with polarized sunglasses, rainbow unevenness may be observed when the in-plane retardation of the substrate film is less than 3000 nm. A preferable lower limit of the in-plane retardation is 4500 nm, and a more preferable lower limit is 6000 nm.

On the other hand, the upper limit of the in-plane retardation is preferably 30000 nm. Even if the base film has a retardation exceeding that, not only a further improvement in visibility can be obtained, but the thickness of the base film becomes considerably thick and the handling property as an industrial material is lowered. To do. The upper limit of the in-plane retardation is more preferably 15000 nm or less, still more preferably 11000 nm, and particularly preferably 9000 nm or less, from the viewpoint of reducing the thickness of the film to ensure thinning or flexibility.

The retardation of the base film can be obtained by measuring the refractive index and thickness in the biaxial direction, and can also be obtained by using a commercially available automatic birefringence measuring apparatus such as KOBRA-21ADH (Oji Scientific Instruments). . The refractive index is a value measured at the wavelength of sodium D line (589 nm).

The base film preferably has a specific range in the ratio of in-plane retardation (Re) and thickness direction retardation (Rth). Thickness direction retardation means the average of the retardation obtained by multiplying two birefringences (ΔNxz and ΔNyz) when the film is viewed from the cross section in the thickness direction by the film thickness d. The smaller the difference between the in-plane retardation and the thickness direction retardation, the more isotropic the birefringence action due to the observation angle, and the smaller the change in retardation due to the observation angle. Therefore, it is considered that rainbow-like color spots due to the observation angle are less likely to occur.

The ratio (Re / Rth) of in-plane retardation and thickness direction retardation of the base film is preferably 0.2 or more, more preferably 0.5 or more, and further preferably 0.6 or more. . As the ratio of the in-plane retardation to the thickness direction retardation (Re / Rth) is larger, the birefringence action is more isotropic, and rainbow-like color spots are less likely to occur due to the observation angle. In a complete uniaxial (uniaxial symmetry) film, the ratio (Re / Rth) between the in-plane retardation and the thickness direction retardation is 2. However, as described above, the mechanical strength in the direction orthogonal to the orientation direction significantly decreases as the film approaches a perfect uniaxial (uniaxial symmetry) film.

On the other hand, the ratio (Re / Rth) between the in-plane retardation and the thickness direction retardation of the base film is preferably 1.5 or less, more preferably 1.2 or less, and further preferably 1 or less. . In order to completely suppress the occurrence of rainbow-like color spots due to the observation angle, the ratio (Re / Rth) between the in-plane retardation and the thickness direction phase difference does not need to be 2, and is 1.5 or less, or A value of 1.2 or less is sufficient. Even when the ratio is 1 or less, it is possible to satisfy the viewing angle characteristics (180 degrees left and right, 120 degrees up and down) required for the EL display device.

(Nz coefficient)
The base film preferably has an Nz coefficient represented by | ny-nz | / | ny-nx | of 1.7 or less. The Nz coefficient can be obtained as follows. The orientation axis direction of the film is obtained using a molecular orientation meter (MOA-6004 type molecular orientation meter, manufactured by Oji Scientific Instruments Co., Ltd.), and the biaxial refractive index (ny, nx, However, ny> nx) and the refractive index (nz) in the thickness direction are determined by an Abbe refractometer (manufactured by Atago Co., Ltd., NAR-4T, measurement wavelength 589 nm). The Nz coefficient can be obtained by substituting nx, ny, and nz obtained in this way into an expression represented by | ny-nz | / | ny-nx |.

If the Nz coefficient of the base film exceeds 1.7, rainbow unevenness may occur depending on the angle when the EL display device is observed from an oblique direction. The Nz coefficient is more preferably 1.65 or less, and still more preferably 1.63 or less. The lower limit value of the Nz coefficient is 1.2. This is because it is difficult in terms of manufacturing technology to obtain a film having an Nz coefficient of less than 1.2. In order to maintain the mechanical strength of the film, the lower limit value of the Nz coefficient is preferably 1.3 or more, more preferably 1.4 or more, and further preferably 1.45 or more.

(Plane orientation)
The base film preferably has a plane orientation degree represented by (nx + ny) / 2−nz below a specific value. Here, the values of nx, ny, and nz are obtained by the same method as for the Nz coefficient. The degree of surface orientation of the base film is preferably 0.13 or less, more preferably 0.125 or less, and still more preferably 0.12 or less. If the degree of surface orientation exceeds 0.13, rainbow unevenness may be observed depending on the angle when the EL display device is observed from an oblique direction. When the plane orientation degree is less than 0.08, the film thickness varies, and the retardation value may be non-uniform in the film plane.

(Manufacturing method of base film)
A film serving as a substrate can be provided with a predetermined in-plane retardation by stretching. The stretching may be uniaxial stretching or biaxial stretching as long as the properties are obtained. The slow axis of the base film may be the longitudinal direction of the base film, the direction orthogonal to the longitudinal direction, or the oblique direction. In addition, the longitudinal direction here means the running direction in the case of continuously producing films. The angle formed between the longitudinal direction of the base film and the slow axis is preferably 10 degrees or less, particularly preferably 7 degrees or less when the slow axis is the longitudinal direction of the base film. When the slow axis of the base film is orthogonal to the longitudinal direction, the angle formed by the longitudinal direction of the base film and the slow axis is preferably 80 to 100 degrees, and particularly preferably 83 to 97 degrees. When the slow axis of the substrate film is oblique, the angle formed by the longitudinal direction of the substrate film and the slow axis is preferably in the range of 35 to 55 degrees.

The stretching conditions will be described specifically by taking a PET base film having a slow axis in a direction orthogonal to the longitudinal direction as an example.
The both ends of the unstretched raw fabric obtained by extruding the melted PET onto a cooling roll are held by clips and guided into a tenter, preheated, and then stretched in the transverse direction while being heated. In addition, you may extend | stretch longitudinally with a continuous roll before extending | stretching of a horizontal direction. Simultaneous biaxial stretching may also be performed. The longitudinal stretching temperature and the transverse stretching temperature are preferably from 80 to 130 ° C, particularly preferably from 90 to 120 ° C. The longitudinal draw ratio is preferably 1 to 3.5 times, particularly preferably 1 to 3 times. Further, the transverse draw ratio is preferably 2.5 to 6 times, particularly preferably 3 to 5.5 times. In order to control the retardation within the above range, it is preferable to control the ratio between the longitudinal draw ratio and the transverse draw ratio. If the difference between the vertical and horizontal draw ratios is too small, it is difficult to increase the retardation. Also, setting the stretching temperature low is a preferable measure for increasing the retardation. In the subsequent heat treatment, the treatment temperature is preferably from 100 to 250 ° C., particularly preferably from 180 to 245 ° C.
In order to obtain a base film having a slow axis in the longitudinal direction, it is preferable to perform longitudinal stretching with a continuous roll. Before the longitudinal stretching step, lateral stretching may be performed.

The angle between the main orientation main axis of the substrate film and the longitudinal direction or the direction orthogonal to the longitudinal direction is preferably 20 degrees or less, more preferably 15 degrees or less, further preferably 10 degrees or less, and more preferably 5 degrees or less. Is particularly preferred. When the angle between the main orientation main axis of the substrate film and the longitudinal direction or the direction orthogonal to the longitudinal direction exceeds 20 degrees, the brightness changes depending on the angle when observed through polarized sunglasses or the like. In addition, when extending in the longitudinal direction, the main alignment direction becomes the longitudinal direction, so that the angle between the main alignment main axis and the longitudinal direction, and when extending in the width direction, the angle between the main alignment main axis and the direction orthogonal to the longitudinal direction; To do.

The thickness of the base film is preferably 30 to 150 μm, more preferably 40 to 100 μm, and further preferably 50 to 80 μm. When the thickness of the substrate film is less than 30 μm, high in-plane retardation is difficult to achieve, and when it exceeds 150 μm, it becomes difficult to handle, and it becomes difficult to reduce the thickness or ensure flexibility.
You may perform the process which improves adhesiveness, such as a corona treatment, a flame treatment, and a plasma treatment, to a base film.

(Easily adhesive layer)
The base film may be provided with an easy-adhesion layer (easy-adhesion layer P1) in order to improve adhesiveness with a polarizing film or an alignment layer described later.
Examples of the resin used for the easy-adhesion layer include polyester resin, polyurethane resin, polyester polyurethane resin, polycarbonate resin, polycarbonate polyurethane resin, and acrylic resin. Among these, polyester resin, polyester polyurethane resin, polycarbonate polyurethane resin, and acrylic resin Resins are preferred. The easy adhesion layer is preferably cross-linked. Examples of the crosslinking agent include isocyanate compounds, melamine compounds, epoxy resins, oxazoline compounds and the like. In addition, addition of a resin similar to the resin used for the alignment layer or polarizing film, such as polyvinyl alcohol, polyamide, polyimide, and polyamideimide, is also a useful means for improving adhesion.

An easy-adhesion layer can be provided by applying to a base film as a water-based paint to which these resins and, if necessary, a crosslinking agent, particles and the like are added, and drying. Examples of the particles include those used for the above-mentioned base material.
The easy adhesion layer can be provided off-line on the stretched substrate film, or can be provided in-line during the film forming process. The easy adhesion layer is preferably provided in-line during the film forming process. When the easy adhesion layer is provided in-line, it may be before longitudinal stretching or before lateral stretching. In particular, it is preferable to provide an easy-adhesion layer in-line by applying the water-based paint immediately before transverse stretching, preheating and heating with a tenter, and drying and crosslinking during the heat treatment step. In addition, when in-line coating is performed immediately before longitudinal stretching by a roll, it is preferable that the aqueous paint is applied and then dried by a vertical dryer and then guided to a stretching roll.
The coating amount of the water-based paint is preferably 0.01 to 1.0 g / m ^{2 and} more preferably 0.03 to 0.5 g / m ² .

(Functional layer)
It is also preferable that a functional layer such as a hard coat layer, an antireflection layer, a low reflection layer, an antiglare layer, or an antistatic layer is provided on the side opposite to the surface on which the polarizing film is laminated. It is a form.
The thickness of these functional layers can be appropriately set, and is preferably 0.1 to 50 μm, more preferably 0.5 to 20 μm, and further preferably 1 to 10 μm. A plurality of these layers may be provided.

When providing a functional layer, you may provide an easily bonding layer (easy-bonding layer P2) between base materials. For the easy-adhesion layer P2, the resins, cross-linking agents, and the like mentioned in the easy-adhesion layer P1 are preferably used. Further, the easy-adhesion layer P1 and the easy-adhesion layer P2 may have the same composition or different compositions.
The easy adhesion layer P2 is also preferably provided in-line. The easy adhesion layer P1 and the easy adhesion layer P2 can be formed by sequentially coating and drying. Moreover, it is also a preferable form to apply the easy-adhesion layer P1 and the easy-adhesion layer P2 simultaneously on both surfaces of the base film.

In addition, in the following description, when it is called a base film, not only the thing which does not provide an easily bonding layer but the thing which provided the easily bonding layer is also included. Similarly, what provided the functional layer is also contained in a base film.

2. Polarizer In the circularly polarizing plate used in the present invention, a polarizer is provided on a substrate film.
As the polarizer, for example, a polarizing film can be used. The polarizing film may be provided directly on the base film, or an orientation layer may be provided on the base film, and the polarizing film may be provided thereon. In the present invention, the term “polarizer” is sometimes used as a general term for the alignment layer and the polarizing film. Moreover, when a polarizing film is provided without providing an alignment layer on a base film, the polarizing film may be referred to as a polarizer.

(Polarizing film)
The polarizing film has a function of allowing polarized light to pass only in one direction. The polarizing film includes a stretched film such as polyvinyl alcohol (PVA) blended with iodine or a dichroic dye, a dichroic dye film or a coating film obtained by blending a polymerizable liquid crystal compound with a dichroic dye, a polyene A stretched film, a wire grid, or the like can be used without particular limitation.
Among these, a polarizing film in which iodine is adsorbed on PVA and a polarizing film in which a dichroic dye is blended with a polymerizable liquid crystal compound are preferable examples.

First, a polarizing film in which iodine is adsorbed on PVA will be described.
A polarizing film in which iodine is adsorbed on PVA is generally uniaxially stretched after immersing an unstretched film of PVA in a bath containing iodine, or a uniaxially stretched film in a bath containing iodine. It can be obtained by dipping and then crosslinking with a boric acid bath.

The thickness of the polarizing film obtained by the above method is preferably 1 to 30 μm, more preferably 1.5 to 20 μm, and further preferably 2 to 15 μm. If the thickness of the polarizing film is less than 1 μm, sufficient polarization characteristics cannot be obtained, and it may be difficult to handle because it is too thin. When the thickness of the polarizing film exceeds 30 μm, it does not meet the purpose of ensuring thinness or flexibility.

When laminating a polarizing film in which iodine is adsorbed on PVA and a base film, it is preferable to bond the base film and the polarizing film together. As the adhesive for bonding, those conventionally used can be used without limitation. Among them, PVA-based aqueous adhesives, ultraviolet curable adhesives, and the like are preferable examples, and ultraviolet curable adhesives are more preferable.

Thus, the polarizing film in which iodine is adsorbed on PVA can be laminated with the base film using a film as a single polarizer. Alternatively, a laminate of a polarizer on a releasable support substrate obtained by coating PVA on a releasable support substrate and stretching in that state (releasable support substrate laminate polarization) It is also possible to laminate by a method of transferring a polarizing film to a substrate film using The method of laminating by this transfer is also preferable as the laminating method of the polarizer and the substrate film, similarly to the above-described laminating method. When this transfer method is used, the thickness of the polarizer is preferably 12 μm or less, more preferably 10 μm or less, further preferably 8 μm or less, and particularly preferably 6 μm or less. Even such a very thin polarizer is easy to handle because of the releasable support substrate, and the polarizer can be easily laminated on the substrate film. By using such a thin polarizer, it is possible to cope with further reduction in thickness and to ensure flexibility.
Note that a technique for laminating a polarizer and a base film is known, and for example, JP-A-2001-350021 and JP-A-2009-93074 can be referred to.

The method for laminating the polarizer and the substrate film by transfer will be specifically described. First, PVA is applied to a thermoplastic resin releasable support substrate that is unstretched or uniaxially stretched perpendicular to the longitudinal direction, and the resulting laminate of the thermoplastic resin releasable support substrate and PVA is obtained. Is stretched 2 to 20 times, preferably 3 to 15 times in the longitudinal direction. The stretching temperature is preferably 80 to 180 ° C, more preferably 100 to 160 ° C. Subsequently, the stretched laminate is immersed in a bath containing a dichroic dye to adsorb the dichroic dye. Examples of dichroic pigments include iodine and organic dyes. When iodine is used as the dichroic dye, an aqueous solution containing iodine and potassium iodide is preferably used as the dyeing bath. Subsequently, the substrate is immersed in an aqueous solution of boric acid, treated, washed with water, and dried. In addition, 1.5 to 3 times of stretching may be performed as preliminary stretching before adsorption of the dichroic dye. In addition, said method is an example and you may adsorb | suck a dichroic dye before extending | stretching and you may perform a process with boric acid before adsorption | suction of a dichroic dye. It is also possible to perform stretching in a bath containing a dichroic dye or in a bath of an aqueous boric acid solution. Further, these steps may be combined in multiple stages.

As the thermoplastic resin releasable support substrate (release film), a polyester film such as polyethylene terephthalate, a polyolefin film such as polypropylene or polyethylene, a polyamide film, a polyurethane film, or the like is used. The release force of the thermoplastic resin can be adjusted by performing corona treatment or providing a release coat, an easy-adhesion coat, or the like on the release support substrate (release film) of the thermoplastic resin.

By laminating the polarizer surface of the releasable support base material laminated polarizer to the base film with an adhesive or adhesive, and then peeling the releasable support base material, the base film and the polarizer are laminated. The body is obtained. The thickness of the pressure-sensitive adhesive generally used is 5 to 50 μm, while the adhesive is 1 to 10 μm. In order to reduce the thickness, it is preferable to use an adhesive, and it is more preferable to use an ultraviolet curable adhesive. It is also preferable to use an adhesive from the viewpoint of the process that no special apparatus is required.

Next, a polarizing film in which a dichroic dye is blended with a polymerizable liquid crystal compound will be described.

The term “dichroic dye” refers to a dye having the property that the absorbance in the major axis direction of a molecule is different from the absorbance in the minor axis direction.

The dichroic dye preferably has an absorption maximum wavelength (λMAX) in the range of 300 to 700 nm. Examples of such dichroic dyes include organic dichroic dyes such as acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes and anthraquinone dyes, and among these, azo dyes are preferable. Examples of the azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes. Among these, bisazo dyes and trisazo dyes are preferable. The dichroic dyes may be used alone or in combination. In order to adjust the color tone (achromatic color), it is preferable to combine two or more types, and it is more preferable to combine three or more types. In particular, it is preferable to use a combination of three or more azo compounds.

Preferred examples of the azo compound include dyes described in JP-A No. 2007-126628, JP-A No. 2010-168570, JP-A No. 2013-101328, JP-A No. 2013-210624, and the like.

It is also preferable that the dichroic dye is a dichroic dye polymer introduced into a side chain of a polymer such as acrylic. Examples of these dichroic dye polymers include polymers mentioned in JP 2016-4055 A, polymers obtained by polymerizing the compounds represented by [Chem. 6] to [Chem. 12] in JP 2014-206682 A, and the like. Can do.

The content of the dichroic dye in the polarizing film is preferably 0.1 to 30% by mass and more preferably 0.5 to 20% by mass in the polarizing film from the viewpoint of improving the orientation of the dichroic dye. 1.0 to 15% by mass is more preferable, and 2.0 to 10% by mass is particularly preferable.

The polarizing film contains a polymerizable liquid crystal compound in order to improve film strength, polarization degree, film homogeneity, and the like. The polymerizable liquid crystal compound includes a polymerized one as a film.
The polymerizable liquid crystal compound is a compound having a polymerizable group and exhibiting liquid crystallinity.
The polymerizable group means a group involved in the polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group means a group capable of undergoing a polymerization reaction with an active radical, an acid, or the like generated from a photopolymerization initiator described later. Examples of the polymerizable group include a vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The compound exhibiting liquid crystallinity may be a thermotropic liquid crystal or a lyotropic liquid crystal, and may be a nematic liquid crystal or a smectic liquid crystal in the thermotropic liquid crystal.

The polymerizable liquid crystal compound is preferably a smectic liquid crystal compound and more preferably a higher order smectic liquid crystal compound in that higher polarization characteristics can be obtained. When the liquid crystal phase formed by the polymerizable liquid crystal compound is a high-order smectic phase, a polarizing film having a higher degree of alignment order can be produced.

Specific examples of preferable polymerizable liquid crystal compounds include, for example, JP-A No. 2002-308832, JP-A No. 2007-16207, JP-A No. 2015-163596, JP-T No. 2007-510946, JP-A No. 2013-114131. Gazette, WO2005 / 045485, Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996).

The content of the polymerizable liquid crystal compound in the polarizing film is preferably 70 to 99.5% by mass, more preferably 75 to 99% by mass in the polarizing film from the viewpoint of increasing the orientation of the polymerizable liquid crystal compound. It is more preferably from 97 to 97% by mass, particularly preferably from 83 to 95% by mass.

A polarizing film containing a polymerizable liquid crystal compound and a dichroic dye can be provided by applying a composition for a polarizing film.
In addition to the polymerizable liquid crystal compound and the dichroic dye, the polarizing film composition may contain a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, a leveling agent, a polymerizable non-liquid crystal compound, a crosslinking agent, and the like. .

As the solvent, any solvent that can dissolve the polymerizable liquid crystal compound can be used. Specific examples of solvents include water; alcohol solvents such as methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol, and cellosolve; ester solvents such as ethyl acetate, butyl acetate, and γ-butyrolactone; acetone, methyl ethyl ketone, and cyclopentanone. And ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as toluene and xylene; ether solvents such as tetrahydrofuran and dimethoxyethane. These solvents may be used alone or in combination.

The polymerization initiator can be used without limitation as long as it can polymerize a polymerizable liquid crystal compound. As the polymerization initiator, a photopolymerization initiator that generates an active radical by light is preferable. Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts, sulfonium salts, and the like.

As the sensitizer, a photosensitizer is preferable. Examples of the photosensitizer include a xanthone compound, an anthracene compound, phenothiazine, and rubrene.

Examples of the polymerization inhibitor include hydroquinones, catechols, and thiophenols.
Examples of the leveling agent include various known surfactants.

The polymerizable non-liquid crystal compound is preferably one that is copolymerized with the polymerizable liquid crystal compound. For example, when the polymerizable liquid crystal compound has a (meth) acryloyloxy group, examples of the polymerizable non-liquid crystal compound include (meth) acrylates. (Meth) acrylates may be monofunctional or polyfunctional. By using polyfunctional (meth) acrylates, the strength of the polarizing film can be improved. When a polymerizable non-liquid crystal compound is used, it is preferably 1 to 15% by mass, more preferably 2 to 10% by mass, and further preferably 3 to 7% by mass in the polarizing film. If the content of the polymerizable non-liquid crystal compound exceeds 15% by mass, the degree of polarization may decrease.

Examples of the crosslinking agent include polymerizable liquid crystal compounds and compounds capable of reacting with functional groups of polymerizable non-liquid crystal compounds. Specific examples of the crosslinking agent include isocyanate compounds, melamines, epoxy resins, oxazoline compounds, and the like.

A polarizing film is provided by coating the composition for a polarizing film directly on a substrate film or an alignment layer, and then, if necessary, drying and heating to cure.

As the coating method, a known method such as a gravure coating method, a die coating method, a bar coating method, an applicator method or the like; a printing method such as a flexo method can be employed.

Drying is conducted at a temperature of 30 to 170 ° C., more preferably 50 to 150 ° C., and even more preferably 70 to 130 ° C., after the coated base film is guided to a hot air dryer or an infrared dryer. The drying time is preferably 0.5 to 30 minutes, more preferably 1 to 20 minutes, and further preferably 2 to 10 minutes.

The heating can be performed to more firmly align the dichroic dye and the polymerizable liquid crystal compound in the polarizing film. The heating temperature is preferably in a temperature range in which the polymerizable liquid crystal compound forms a liquid crystal phase.

Since the composition for polarizing films contains a polymerizable liquid crystal compound, it is preferably cured. Examples of the curing method include heating and light irradiation, and light irradiation is preferable. The dichroic dye can be fixed in an oriented state by curing. Curing is preferably performed in a state where a liquid crystal phase is formed on the polymerizable liquid crystal compound, and may be cured by light irradiation at a temperature showing the liquid crystal phase.
Examples of light in the light irradiation include visible light, ultraviolet light, and laser light. In view of easy handling, ultraviolet light is preferable.

The irradiation intensity is different in the kind or amount of the polymerization initiator or the resin (monomers), for example, preferably 100 ~ 10000mJ / cm ² at 365nm reference, more preferably 200 ~ 5000mJ / cm ^2.

The polarizing film is formed by applying the polarizing film composition onto an alignment layer provided as necessary, so that the dye is aligned along the alignment direction of the alignment layer, and as a result, has a polarization transmission axis in a predetermined direction. Become. When the composition for a polarizing film is directly coated on a substrate without providing an alignment layer, the polarizing film can be oriented by irradiating with polarized light to cure the composition for a polarizing film. Further, it is preferable that the dichroic dye is firmly aligned along the alignment direction of the polymer liquid crystal by subsequent heat treatment.

In this case, the thickness of the polarizing film is usually 0.1 to 5 μm, preferably 0.3 to 3 μm, more preferably 0.5 to 2 μm.

When laminating a polarizing film containing a polymerizable liquid crystal compound and a dichroic dye and a base film, not only a method of laminating by directly providing a polarizing film on the base film, but also the above-mentioned on another release film A method of providing a polarizing film according to the method and transferring the film to a base film is also preferable. Examples of the release film include a release support substrate used in the release support substrate laminated polarizer laminated with the above-described release support substrate, and examples include a polyester film and a polypropylene film. Is mentioned as a particularly preferred release film. The release force can be adjusted by performing corona treatment on the release film or providing a release coat, an easy-adhesion coat, and the like.

The method for transferring the polarizing film to the base film is the same as the method for the release support base laminate polarizer laminated with the above-mentioned release support base.

(Orientation layer)
As described above, the polarizer used in the present invention may be only a polarizing film, or may have a configuration in which a polarizing film and an alignment layer are combined.
The alignment layer controls the alignment direction of the polarizing film, and a polarizer having a higher degree of polarization can be provided by providing the alignment layer.
The alignment layer may be any alignment layer as long as the polarizing film can be brought into a desired alignment state. Examples of a method for giving an alignment state to the alignment layer include a rubbing treatment on the surface, oblique vapor deposition of an inorganic compound, and formation of a layer having microgrooves. Furthermore, a method of forming a photo-alignment layer in which molecules are aligned by irradiation with polarized light to generate an alignment function is also preferable.
Hereinafter, two examples of the rubbing treatment alignment layer and the photo alignment layer will be described.

Rubbing treatment alignment layer As the polymer material used for the alignment layer formed by the rubbing treatment, polyvinyl alcohol and derivatives thereof, polyimide and derivatives thereof, acrylic resin, polysiloxane derivatives and the like are preferably used.

First, after applying a coating solution for a rubbing treatment alignment layer containing the above polymer material on a substrate film, heat drying and the like are performed to obtain an alignment layer before the rubbing treatment. The alignment layer coating solution may have a crosslinking agent. Examples of the crosslinking agent include compounds containing a plurality of isocyanate groups, epoxy groups, oxazoline groups, vinyl groups, acrylic groups, carbodiimide groups, alkoxysilyl groups, etc .; amide resins such as melamine compounds; and phenol resins.

The solvent for the rubbing treatment alignment layer coating solution can be used without limitation as long as it dissolves the polymer material. Specific examples of solvents include water; alcohol solvents such as methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol, and cellosolve; ester solvents such as ethyl acetate, butyl acetate, and γ-butyrolactone; acetone, methyl ethyl ketone, and cyclopentanone. And ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as toluene and xylene; ether solvents such as tetrahydrofuran and dimethoxyethane. These solvents may be used alone or in combination.

The concentration of the coating solution for the rubbing treatment alignment layer can be appropriately adjusted depending on the type of polymer, the thickness of the alignment layer to be produced, and the like, and expressed as a solid content concentration of 0.2 to 20% by mass. The range of 0.3 to 10% by mass is more preferable.
As a coating method, known methods such as a gravure coating method, a die coating method, a bar coating method, an applicator method and the like; a flexo method and other printing methods are employed.
The temperature for drying by heating depends on the substrate film, but in the case of PET, it is preferably in the range of 30 to 170 ° C, more preferably in the range of 50 to 150 ° C, and further preferably in the range of 70 to 130 ° C. When the drying temperature is too low, it is necessary to take a long drying time, which may be inferior in productivity. If the drying temperature is too high, it will affect the orientation state of the base film, the retardation will decrease, or the thermal shrinkage of the base film will increase, so that the optical function as designed cannot be achieved, and the flatness will be poor. Such problems arise. The heat drying time is usually 0.5 to 30 minutes, preferably 1 to 20 minutes, and more preferably 2 to 10 minutes.

The thickness of the rubbing-treated alignment layer is preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm, and further preferably 0.1 to 1 μm.

The rubbing treatment can be generally performed by rubbing the surface of the polymer layer in a certain direction with paper or cloth. In general, the surface of the alignment film is rubbed using a rubbing roller of a raised fabric of fibers such as nylon, polyester, and acrylic.
In order to provide a polarizing film having a transmission axis in a predetermined direction with respect to the longitudinal direction of the long base film, the rubbing direction of the alignment layer needs to be set to an angle corresponding thereto. The angle can be adjusted by adjusting the angle between the rubbing roller and the base film, adjusting the transport speed of the base film, the number of rotations of the roller, and the like.

It should be noted that the base film can be directly rubbed so that the base film surface has an alignment layer function. This case is also included in the technical scope of the present invention.

Photo-alignment layer A photo-alignment layer is a coating liquid containing a polymer or monomer having a photoreactive group and a solvent, which is applied to a substrate film and irradiated with polarized light, preferably polarized ultraviolet rays, to impart alignment regulating power. It refers to the oriented film. The photoreactive group refers to a group that generates liquid crystal alignment ability by light irradiation. Specifically, it causes photoreactions that are the origin of liquid crystal alignment ability, such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photolysis reaction caused by light irradiation. is there. Among the photoreactive groups, those that cause a dimerization reaction or a photocrosslinking reaction are preferable in terms of excellent orientation and maintaining the smectic liquid crystal state of the polarizing film. The photoreactive group capable of causing the reaction as described above is preferably an unsaturated bond, particularly a double bond, from the group consisting of C = C bond, C = N bond, N = N bond, and C = O bond. Particularly preferred are groups having at least one selected.

Examples of the photoreactive group having a C═C bond include a vinyl group, a polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C═N bond include groups having a structure such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N = N bond include those having a basic structure of azobenzene group, azonaphthalene group, aromatic heterocyclic azo group, bisazo group, formazan group, azoxybenzene and the like. Examples of the photoreactive group having a C═O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a halogenated alkyl group.
Among these, a photoreactive group capable of causing a photodimerization reaction is preferable, and a cinnamoyl group and a chalcone group require a relatively small amount of polarized light irradiation necessary for photoalignment, and have excellent thermal stability or stability over time. It is preferable because a layer is easily obtained. Further, as the polymer having a photoreactive group, a polymer having a cinnamoyl group in which the terminal portion of the polymer side chain has a cinnamic acid structure is particularly preferable. Examples of the structure of the main chain include polyimide, polyamide, (meth) acryl, and polyester.

Specific examples of the alignment layer include, for example, JP-A-2006-285197, JP-A-2007-76839, JP-A-2007-138138, JP-A-2007-94071, and JP-A-2007-121721. JP 2007-140465, JP 2007-156439, JP 2007-133184, JP 2009-109831, JP 2002-229039, JP 2002-265541, JP 2002. -317013, JP-T 2003-520878, JP-T 2004-529220, JP-A 2013-33248, JP-A 2015-7702, JP-A 2015-129210, etc. Is mentioned.

The solvent for the photo-alignment layer forming coating solution can be used without limitation as long as it dissolves the polymer and monomer having a photoreactive group. Specific examples of the solvent include those listed for the rubbing treatment alignment layer. If necessary, a photopolymerization initiator, a polymerization inhibitor, various stabilizers, and the like can be added to the photoalignment layer forming coating solution. Further, a polymer having a photoreactive group and a polymer other than the monomer, a monomer having no photoreactive group copolymerizable with the monomer having a photoreactive group, and the like may be added to the photoalignment layer forming coating solution. .

Examples of the concentration of the coating liquid for forming the photo-alignment layer, the coating method, the drying conditions, and the like can be given as those exemplified in the rubbing treatment orientation layer. The thickness of the photo-alignment layer is also the same as the preferable thickness of the rubbing treatment alignment layer.

By irradiating the photo-alignment layer obtained in this way with polarized light in a predetermined direction with respect to the longitudinal direction of the base film, the direction of the orientation regulating force is the longitudinal direction of the long base film. A photo-alignment layer having a predetermined direction can be obtained.

The polarized light may be irradiated directly to the photo-alignment layer before alignment, or may be irradiated through the substrate film.

The wavelength of polarized light is preferably a wavelength region in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, ultraviolet rays having a wavelength in the range of 250 to 400 nm are preferable.
Examples of the polarized light source include a xenon lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, an ultraviolet laser such as KrF and ArF, and the like, and a high-pressure mercury lamp, an ultra-high pressure mercury lamp and a metal halide lamp are preferable.

Polarized light can be obtained, for example, by passing light from the light source through a polarizer. The direction of polarized light can be adjusted by adjusting the polarization angle of the polarizer. Examples of the polarizer include a polarizing filter; a polarizing prism such as Glan Thompson and Grant Taylor; and a wire grid type polarizer. The polarized light is preferably substantially parallel light.

The direction of the alignment regulating force of the photo-alignment layer can be arbitrarily adjusted by adjusting the angle of the polarized light to be irradiated.

The irradiation intensity is different in the kind or amount of the polymerization initiator or the resin (monomers), for example, preferably 10 ~ 10000mJ / cm ² at 365nm reference, more preferably 20 ~ 5000mJ / cm ^2.

(An angle between the transmission axis of the polarizer and the slow axis of the base film)
The angle between the transmission axis of the polarizer and the slow axis of the substrate film is not particularly limited. For the purpose of preventing blackout or coloring when viewing images with polarized sunglasses, the range of 30 to 60 degrees is preferable, and the range of 35 to 55 degrees is more preferable. In order to reduce slight iridescence and the like when observed from an oblique direction with a shallow angle with the naked eye, it is set to 10 degrees or less, further 7 degrees or less, or 80 to 100 degrees, further 83 to 97 degrees. It is preferable to do. These angles can be adjusted by the bonding angle between the base film and the polarizer, the stretching direction of the diagonal stretching of the base film, or the orientation control angle of the orientation layer.

3. Retardation layer In the circularly polarizing plate used in the present invention, a retardation layer is present on the side opposite to the substrate film surface of the polarizer. That is, the circularly polarizing plate has a retardation layer on the electroluminescence (EL) cell side of the polarizer. The self-supporting film does not exist between the polarizer and the retardation layer, or only one sheet exists (here, the retardation layer itself is included between the polarizer and the retardation layer). This is one of the features of the EL display device of the present invention. Here, the self-supporting film refers to a film that exists as a film independently in the process.
Further, the “retardation layer” mentioned here is for providing a function as a circularly polarizing plate, and specifically means a quarter wavelength layer, a half wavelength layer, a C plate layer, or the like. To do.
The absence of a self-supporting film between the polarizer and the retardation layer means that a retardation layer that is not a self-supporting film is directly laminated on the polarizer. The term “directly” as used herein means that there is no layer or only an adhesive layer or a pressure-sensitive adhesive layer even if it exists between the polarizer and the retardation layer and between the retardation layers. Means that.
The presence of one self-supporting film between the polarizer and the retardation layer means that only one of the polarizer protective film and all the retardation layers is a self-supporting film.

The retardation layer has a ½ wavelength layer and a ¼ wavelength layer.
The half-wave layer is a separately prepared coating-type half-wave layer provided on an oriented film (self-supporting film) such as polycarbonate or cycloolefin or a triacetyl cellulose-based (TAC) film. It can obtain by sticking together the phase difference film (self-supporting film). However, in terms of ensuring thinness or flexibility, it is preferable to provide a coating type ½ wavelength layer directly on the polarizer.
The coating type ½ wavelength layer is a ½ wavelength layer formed by coating the ½ wavelength layer itself, and does not become an independent state as a single body. As a method of providing a ½ wavelength layer, a method of coating a retardation compound on a polarizer, a ½ wavelength layer is separately provided on a substrate having a releasability, and this is formed on the polarizer. Examples include a transfer method. The half-wave layer is preferably a layer made of a liquid crystal compound. Examples of the liquid crystal compound include a rod-like liquid crystal compound, a polymer liquid crystal compound, and a liquid crystal compound having a reactive functional group. As a method of coating a retardation compound on the polarizer, the liquid crystal is subjected to rubbing treatment or the alignment layer as described above is provided on the polarizer to give alignment control power. It is preferable to apply the compound.

In the method of separately providing a coating type ½ wavelength layer on a releasable substrate and transferring this onto a polarizer, the substrate having releasability is rubbed or the releasable group It is preferable to apply the liquid crystal compound (1/2 wavelength layer) after providing an alignment layer as described above on the material to impart alignment control power.
Further, as a method for transferring, a method in which a birefringent resin is applied to a releasable base material and the whole base material is stretched to form a ½ wavelength layer is also preferable.

The transfer-type half-wave layer thus obtained is bonded to a polarizer using an adhesive or a pressure-sensitive adhesive, and then the releasable substrate is peeled off. In order to reduce the thickness, it is preferable to use an adhesive, particularly an ultraviolet curable adhesive. It is also preferable to use an adhesive from the viewpoint of the process that no special apparatus is required.
There is a method in which a polarizing half-wave layer is separately provided on a releasable substrate and the polarizer is transferred onto the polarizer because the polarizer is not easily affected by the coating solvent of the half-wave layer. preferable.

The front retardation of the ½ wavelength layer is preferably 200 to 360 nm, and more preferably 240 to 300 nm.

These methods and the retardation layer can be referred to, for example, JP-A No. 2008-149577, JP-A No. 2002-303722, WO 2006/100830, JP-A No. 2015-64418, and the like.

The preferable material, form, manufacturing method, lamination method and the like of the ¼ wavelength layer are the same as those of the ½ wavelength layer described above. The quarter wavelength layer is preferably provided on the half wavelength layer by coating or by transfer.

The front retardation of the quarter wavelength layer is preferably 100 to 180 nm, and more preferably 120 to 150 nm.

The angle (θ) between the orientation axis (slow axis) of the ½ wavelength layer and the transmission axis of the polarizer is preferably 5 to 20 degrees, more preferably 7 to 17 degrees. The angle between the alignment axis (slow axis) of the ½ wavelength layer and the alignment axis (slow axis) of the ¼ wavelength layer is preferably in the range of 2θ + 45 degrees ± 10 degrees, and in the range of 2θ + 45 degrees ± 5 degrees. More preferably, the range of 2θ + 45 degrees ± 3 degrees is even more preferable.

These angles can be adjusted by the bonding angle, the stretching direction of the alignment film, and the like when the alignment film is bonded.
In the case of the coating type quarter wavelength layer and half wavelength layer, it can be controlled by the rubbing angle, the irradiation angle of polarized ultraviolet rays, and the like.
In a method in which a coating type quarter wavelength layer is provided on a substrate and this is transferred onto a polarizer, the rubbing angle or polarized ultraviolet rays are adjusted so that a predetermined angle is obtained when they are bonded by roll-to-roll. It is preferable to control by the irradiation angle.
In addition, when using an oriented film, and when a birefringent resin is applied to a base film and stretched together with the base material, it is slanted so as to be at a predetermined angle when bonded by roll-to-roll. It is preferable to stretch in the direction.

Furthermore, in order to reduce a change in coloring when viewed from an oblique direction, it is also preferable to provide a C plate layer on the quarter wavelength layer. As the C plate layer, a positive or negative C plate layer is used according to the characteristics of the quarter wavelength layer or the half wavelength layer. The C plate layer is preferably a liquid crystal compound layer. The C plate layer may be provided by directly applying a coating solution to be the C plate layer on the quarter wavelength layer, or a separately prepared C plate layer may be transferred.

As these lamination methods, various methods can be adopted. For example, the following method is mentioned.
A method of providing a ½ wavelength layer on a polarizer by transfer, and further providing a ¼ wavelength layer on the polarizer by transfer.
A method in which a quarter wavelength layer and a half wavelength layer are provided in this order on a release film, and this is transferred onto a polarizer.
A method in which a 1/2 wavelength layer is provided on a polarizer by coating, and a 1/4 wavelength layer is provided by transfer.
A method in which a film-like half-wave layer is prepared, and a quarter-wave layer is provided thereon by coating or transfer, and this is laminated on a polarizer.

In addition, various methods can be employed when the C plate layer is laminated. For example, a method of providing a C plate layer by coating or transferring on a quarter wavelength layer provided on a polarizer, a method of previously laminating a C plate layer on a quarter wavelength layer to be transferred or bonded, etc. Can be mentioned.
In the present invention, all layers from the polarizer to the C plate layer (including the C plate layer) are included between the polarizer and the quarter wavelength layer (including the quarter wavelength layer). Including) is preferably a coating layer. This means that there is no self-supporting film on the opposite side of the polarizer from the base film. Specifically, only an arbitrary combination of an adhesive layer, a pressure-sensitive adhesive layer, a protective coating layer, an alignment layer, and a coating type retardation layer is present on the opposite side of the polarizer from the base film. That is. With such a configuration, the circularly polarizing plate can be thinned or flexible.

As a specific preferred lamination example between the polarizer and the quarter wavelength layer,
Polarizer / 1/2 wavelength layer / adhesive layer / 1/4 wavelength layer,
Polarizer / adhesive layer / 1/2 wavelength layer / adhesive layer / 1/4 wavelength layer,
Polarizer / protective coat layer / 1/2 wavelength layer / adhesive layer / ¼ wavelength layer,
Examples include polarizer / protective coat layer / adhesive layer / 1/2 wavelength layer / adhesive layer / ¼ wavelength layer.
In the above, the pressure-sensitive adhesive layer may be an adhesive layer. The quarter wavelength layer and the half wavelength layer may include an alignment layer on either side.

As the pressure-sensitive adhesive layer, rubber-based, acrylic-based, urethane-based, olefin-based, and silicone-based pressure-sensitive adhesives are used without limitation. Among these, an acrylic adhesive is preferable. The pressure-sensitive adhesive can be applied to an object, for example, a polarizer surface of a polarizing plate. A method in which a pressure-sensitive adhesive layer is provided by peeling off a single-sided release film of a substrate-less optical transparent pressure-sensitive adhesive (release film / pressure-sensitive adhesive layer / release film) and then bonding the film to the polarizer surface is preferable. As the adhesive, an ultraviolet curing type, urethane type, and epoxy type are preferably used.
The adhesive layer or the pressure-sensitive adhesive layer is used for bonding a polarizer, a protective coat layer, a coating type retardation layer, or an image display cell.

In the above description, the retardation layer (1/4 wavelength layer and 1/2 wavelength layer) is provided on the laminate of the base film and the polarizer and then bonded to the object. A retardation layer (a quarter wavelength layer and a half wavelength layer) may be provided in advance, and a laminate of a base film and a polarizer may be bonded thereto. The same applies when the C plate layer is provided.

The thickness of the circularly polarizing plate thus obtained is preferably 130 μm or less, more preferably 100 μm or less, further preferably 90 μm or less, and particularly preferably 85 μm or less.

Furthermore, a circularly polarized light reflecting layer made of a liquid crystal compound may be provided on the retardation layer of the circularly polarizing plate (surface opposite to the polarizer). The circularly polarized light reflecting layer is preferably a cholesteric liquid crystal layer. The cholesteric liquid crystal layer may be a single layer. However, since the cholesteric liquid crystal layer has wavelength selectivity in the reflection characteristics, a plurality of cholesteric liquid crystal layers should be provided in order to obtain uniform reflection characteristics in a wide visible light region. Is preferred. Two or more cholesteric liquid crystal layers are more preferable, and three or more layers are more preferable. The cholesteric liquid crystal layer is preferably 7 layers or less, more preferably 6 layers or less, and particularly preferably 5 layers or less.

The circularly polarized light reflecting layer is preferably provided by coating or transferring a circularly polarized light reflecting layer coating material containing a liquid crystal compound.
Examples of the liquid crystal compound used in the circularly polarized light reflecting layer include the liquid crystal compounds used in the aforementioned polarizing film or retardation layer.

Furthermore, in order to align the circularly polarized light reflecting layer with cholesteric liquid crystal, it is preferable that a chiral agent is contained in the circularly polarized light reflecting layer coating material. By containing a chiral agent, a helical structure of a cholesteric liquid crystal phase is induced, and a cholesteric liquid crystal phase is easily obtained.
The chiral agent is not particularly limited, and a known chiral agent can be used. As the chiral agent, for example, Liquid Crystal Device Handbook, Chapter 3-4-3, TN (Twisted Nematic), STN (Super-twisted nematic display) chiral agent, 199 pages, Japan Society for the Promotion of Science, 142nd Committee, And compounds described in 1989, isosorbide, isomannide derivatives and the like. The chiral agent preferably has a polymerizable group. The compounding amount of the chiral agent is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the liquid crystal compound.

When the circularly polarized light reflection layer is provided on the retardation layer by coating, it may be applied directly on the retardation layer, or an alignment layer may be provided and applied thereon. When the circularly polarized light reflecting layer is provided by transfer, an orientation layer may be provided directly on the releasable substrate or the circularly polarized light reflecting layer coating may be applied thereon. A circularly polarized light reflection layer and a retardation layer may be provided in this order on the releasable substrate, and this may be transferred onto the polarizer. A part of the circularly polarized light reflecting layer and the retardation layer are provided in this order on the releasable substrate, and another part of the retardation layer is separately provided on the polarizer. It may be transferred to the top. The alignment layer described above is preferably used.

Examples of the circularly polarized light reflecting layer include JP-A-1-133003, JP-A-3416302, JP-A-3363565, JP-A-8-271731, International Publication No. 2016/194497, and JP-A-2018-10086. Can be referred to.

The thickness of the circularly polarized light reflecting layer is preferably 2.0 to 150 μm, more preferably 5.0 to 100 μm. In addition, when a circularly-polarized-light reflective layer is a multiple layer, the thickness in a total number is also the said range.

By combining the circularly polarized light reflection layer with the circularly polarizing plate, it is possible to reduce a decrease in luminance when an antireflection circularly polarizing plate is provided in the EL display device. Furthermore, a polarizer, a retardation layer, and a circularly polarized light reflecting layer are provided by coating or transfer, and a self-supporting film is provided between the polarizer and the circularly polarized light reflecting layer (including the polarizer itself and the circularly polarized light reflecting layer). By adopting a structure that does not have the circularly polarizing plate, it is possible to make the circularly polarizing plate thinner and to easily cope with the thinning of the EL display device. Such a structure is also optimal for flexible EL display devices such as foldable and rollable.

B. EL Cell The EL display device of the present invention is provided with the above-described circularly polarizing plate on the viewing side with respect to the EL cell. As the EL cell, a known one can be used without limitation, and among them, the organic EL cell is preferable in that it is thin. The EL cell and the circularly polarizing plate are preferably bonded with an adhesive.
The EL display device of the present invention uses a base film having a specific in-plane retardation, and the number of self-supporting films existing between the polarizer and the retardation layer is 1 or less, and 1 / Since a circularly polarizing plate having a two-wavelength layer and a quarter-wavelength layer is used, it is excellent in visibility (suppression of rainbow spots), can be thinned, and troubles are unlikely to occur in the manufacturing process. In particular, it is suitably used in large-sized EL display devices of 40 type (the diagonal length of the display portion is 40 inches) or more, and further 50 type (the diagonal length of the display portion is 50 inches) or more.
In addition, in the case of a flexible EL display device, even when it is repeatedly bent or left in a high temperature state, the stacked members are not easily peeled off and are not easily marked.
As a flexible EL display device, it can be folded into a V-shaped, Z-shaped, W-shaped, double-spread-shaped EL display device (foldable EL display device), or rolled up when carried. Any EL display device (winding EL display device) is preferably used.

When the folding EL display device has a display portion on the inner side of the folding, the bending radius of the circularly polarizing plate in the folded state becomes small. In the case of such an EL display device, the main film orientation direction of the base film is arranged in a direction perpendicular to the folding direction (folding operation direction), thereby effectively reducing the occurrence of folding marks due to repeated folding operations. be able to. In the vertical direction, the angle between the main orientation direction and the folding direction of the base film is preferably 75 to 105 degrees, more preferably 80 to 100 degrees, and still more preferably 83 to 97 degrees.

The reason why the generation of folding marks can be reduced is that the base film is stretched by repeated folding operations, but the base film is easy to stretch because the stretched direction is perpendicular to the main molecular orientation direction. It is done. The flexible image display device of the present invention can be suitably used for a foldable image display device having a bending radius of 5 mm or less, further 4 mm or less, and particularly 3 mm.
In the case where the folding EL display device has a display part on the folding outer surface side of the device, or the bending radius does not decrease even on the inner surface, or in the case of a roll-up image display device, the base film The main orientation direction can be used without particular limitation. However, in such a case, it is also a preferable form that the main orientation direction of the base film is parallel to the folding direction. By making them parallel, the flatness of the entire image display device when it is spread tends to be improved. In this case, the angle between the main orientation direction and the folding direction of the base film is preferably 15 degrees or less, more preferably 10 degrees or less, and even more preferably 7 degrees or less.
The flexible EL display device of the present invention is not peeled even when it is repeatedly bent or left in a high temperature state, is not easily folded, and has excellent visibility. Furthermore, when a polyester film is used as the base film of the circularly polarizing plate, an EL display device having a circularly polarizing plate excellent in moisture permeability, dimensional stability, mechanical strength, and chemical stability is provided. Can do.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely with reference to an Example, this invention is not limited to the following Example. The present invention can be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention, and they are all included in the technical scope of the present invention.
The physical property evaluation methods in the examples are as follows.

(1) Retardation (Re)
Retardation is a parameter defined by the product (ΔNxy × d) of the biaxial refractive index anisotropy (ΔNxy = | nx−ny |) on the film and the film thickness d (nm). Yes, a measure of optical isotropy and anisotropy. The biaxial refractive index anisotropy (ΔNxy) was determined by the following method. Using a molecular orientation meter (MOA-6004 type molecular orientation meter, manufactured by Oji Scientific Instruments), the orientation axis direction of the film is obtained, and a 4 cm × 2 cm rectangle is cut out and measured so that the orientation axis direction becomes the long side. A sample was used. For this sample, the biaxial refractive index (nx, ny) perpendicular to each other and the refractive index (nz) in the thickness direction were measured using an Abbe refractometer (NAG-4T, measurement wavelength 589 nm, manufactured by Atago Co., Ltd.). The absolute value (| nx−ny |) of the difference between the biaxial refractive indexes was defined as the refractive index anisotropy (ΔNxy). The thickness d (nm) of the film was measured using an electric micrometer (manufactured by Fine Reef, Millitron 1245D), and the unit was converted to nm. Retardation (Re) was determined from the product (ΔNxy × d) of refractive index anisotropy (ΔNxy) and film thickness d (nm).

(2) Nz coefficient The value obtained by | ny-nz | / | ny-nx | was defined as the Nz coefficient. However, the values of ny and nx were selected so that ny> nx.

(3) Degree of plane orientation (ΔP)
The value obtained by (nx + ny) / 2−nz was defined as the degree of plane orientation (ΔP).

(4) Thickness direction retardation (Rth)
Thickness direction retardation refers to two birefringences ΔNxz (= | nx−nz |) and ΔNyz (= | ny−nz |), respectively, when viewed from the cross section in the film thickness direction. It is a parameter which shows the average of retardation obtained. Thickness direction retardation (Rth) is calculated by calculating nx, ny, nz and film thickness d (nm) in the same manner as the retardation measurement, and calculating an average value of (ΔNxz × d) and (ΔNyz × d). )

(5) Light transmittance at a wavelength of 380 nm Using a spectrophotometer (manufactured by Hitachi, U-3500 type), the light transmittance in the wavelength region of 300 to 500 nm of each film is measured using the air layer as a standard, and the light at a wavelength of 380 nm. The transmittance was determined.
The various characteristics of the substrate film are average values obtained by sampling three points in the width direction (three points at the center and both ends).

(6) Angle between film orientation principal axis and longitudinal direction or direction perpendicular to longitudinal direction The orientation principal axis direction of the film is determined using a molecular orientation meter (MOA-6004 type molecular orientation meter, manufactured by Oji Scientific Instruments) Expressed as an angle with the longitudinal direction or the direction orthogonal to the longitudinal direction.

(7) Base Film and Thickness of Circular Polarizing Plate The thickness of the base film and the circular polarizing plate was measured with a commercially available digital thickness meter.

(8) Thickness of each layer by coating The thickness of each layer by coating is obtained by embedding a coating on a PET film (PET which has been subjected to an easy adhesion treatment if necessary) under the same coating conditions with an epoxy resin. Was cut out and observed with a microscope. The microscope used was an optical microscope, a transmission electron microscope, or a scanning electron microscope depending on the thickness.

(9) Handling property The prepared circularly polarizing plate was cut out corresponding to A5, and wound around a paper tube having an outer diameter of 6 inches together with a biaxially stretched PET film having a thickness of 50 μm so that the length direction was the winding direction. For winding, a circularly polarizing plate sample was inserted when 3 m of the PET film was wound, and a 7 m PET film was further wound. Moreover, what wound up only the base film as a blank was prepared. These were stored at 40 ° C. for 3 days, returned to room temperature, unwound, placed on a glass plate with the convex part of the curl up, and the state of curl after 30 minutes was observed. We also tried to hold it from above and flatten easily. The evaluation criteria are as follows.
A: Almost the same as the blank and almost no curling.
○: The curl was slightly stronger than the blank, but it was easy to flatten.
Δ: The curl was stronger than the blank, but it was possible to make it flat.
X: The curl was considerably stronger than that of the blank, and it was difficult to make it flat.

(10) Polarized sunglasses support The circularly polarizing plate (the circularly polarizing plate disposed on the viewing side from the organic EL element) is removed from a commercially available organic EL display (LG EL C55 manufactured by LG). The circularly polarizing plate obtained in the above was placed in an organic EL display so that the PET film was placed on the viewing side. The polarizer was arranged so that the absorption axis of the polarizer was the same as the absorption axis of the polarizer of the original circularly polarizing plate.
The display was observed with polarized sunglasses. The evaluation criteria are as follows.
○: An image can be seen without observing rainbow spots (the slow axis direction of the base film and the absorption axis direction of the polarizer are about 45 degrees)
×: The image has an angle at which the image is blacked out and cannot be seen (the slow axis direction of the base film and the absorption axis direction of the polarizer are orthogonal or parallel)

(11) Antireflection effect The antireflection effect of the EL display device used in the evaluation of (10) above was visually confirmed.
A: An antireflection effect almost equal to that of the original circularly polarizing plate was recognized.
X: The antireflection effect was not recognized.

(12) r = 3 Bending resistance A circularly polarizing plate sample having a size of 50 mm × 100 mm is prepared, and the bending radius is set to 3 mm using an unloaded U-shaped stretch tester (manufactured by Yuasa System Equipment Co., Ltd., DLDMMLH-FS). And was bent 100,000 times at a speed of 1 time / second. At that time, the sample is fixed at the position of 10 mm at both ends on the long side, the bent portion is 50 mm × 80 mm, the inside of the bend is on the base film side, and the slow axis of the base film is perpendicular to the bending direction. I did it. After completion of the bending process, the sample was placed on a flat surface with the bending inner side down, and a visual inspection was performed. The evaluation criteria are as follows.
A: The deformation of the sample cannot be confirmed.
○: There is deformation of the sample, but when placed horizontally, the maximum height is less than 5 mm.
X: The sample has a crease, or when placed horizontally, the maximum height is 5 mm or more.

(13) r = 5 Bend resistance r = 3 Bend resistance except that the bend radius is set to 5 mm, the outside of the bend is the base film side, and the slow axis of the base film is parallel to the bending direction. It carried out similarly to a flexibility test.

(14) Heat-resistant bendability A sample having a size of 50 mm × 100 mm is bent at 180 degrees in the direction of the long side so that the bending radius is 3 mm with the base film surface facing inward, and fixed with a jig at a temperature of 60 ° C. And left at 65% RH for 3 hours. Thereafter, the fixture was removed at room temperature, and the state after 1 hour was observed. The slow axis and the folding direction of the base film were made to be orthogonal. The evaluation criteria are as follows.
◎: Almost returned to a plane ○: Bent slightly (less than 20 degrees)
X: It was in a bent state (20 degrees or more)

<Manufacture of easy adhesion layer components>
(Polyester resin polymerization)
In a stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux condenser, 194.2 parts by mass of dimethyl terephthalate, 184.5 parts by mass of dimethyl isophthalate, 14.8 parts by mass of dimethyl-5-sodium sulfoisophthalate Then, 233.5 parts by mass of diethylene glycol, 136.6 parts by mass of ethylene glycol, and 0.2 parts by mass of tetra-n-butyl titanate were charged, and a transesterification reaction was performed at a temperature of 160 ° C. to 220 ° C. over 4 hours. Next, the temperature of the mixture was raised to 255 ° C., the pressure of the reaction system was gradually reduced, and the mixture was reacted for 1 hour and 30 minutes under a reduced pressure of 30 Pa to obtain a copolyester resin. The obtained copolyester resin was light yellow and transparent. The reduced viscosity of the copolyester resin was measured and found to be 0.70 dl / g. The reduced viscosity was measured at 30 ° C. using 25 mL of a mixed solvent of phenol (60% by mass) and 1,1,2,2-tetrachloroethane (40% by mass) as a solvent with respect to 0.1 g of resin. Value. The glass transition temperature by DSC was 40 ° C.

(Preparation of aqueous polyester dispersion)
In a reactor equipped with a stirrer, a thermometer and a reflux device, 30 parts by mass of a polyester resin and 15 parts by mass of ethylene glycol n-butyl ether were added and stirred while heating at 110 ° C. to dissolve the resin. After the resin was completely dissolved, 55 parts by mass of water was gradually added while stirring the polyester solution. After completion of the addition, the mixed solution was cooled to room temperature while stirring to obtain a milky white polyester aqueous dispersion having a solid content of 30% by mass.

(Preparation of aqueous polyvinyl alcohol solution)
In a vessel equipped with a stirrer and a thermometer, 90 parts by mass of water was added, and 10 parts by mass of polyvinyl alcohol resin (manufactured by Kuraray, polymerization degree 500 and saponification degree 74%) was gradually added. After completion of the addition, the mixture was heated to 95 ° C. with stirring to dissolve the resin. After the resin was dissolved, the mixture was cooled to room temperature while stirring to obtain a polyvinyl alcohol aqueous solution having a solid content of 10% by mass.

(Polymerization of block polyisocyanate crosslinking agent used in easy-adhesion layer P1)
In a flask equipped with a stirrer, a thermometer and a reflux condenser, 100 parts by mass of a polyisocyanate compound having an isocyanurate structure using hexamethylene diisocyanate as a raw material (manufactured by Asahi Kasei Chemicals, Duranate TPA), 55 parts by mass of propylene glycol monomethyl ether acetate, And 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) were charged and kept at 70 ° C. for 4 hours in a nitrogen atmosphere. Thereafter, the temperature of the reaction solution was lowered to 50 ° C., and 47 parts by mass of methyl ethyl ketoxime was added dropwise. The infrared spectrum of the reaction solution was measured to confirm that the absorption of the isocyanate group had disappeared, and a block polyisocyanate aqueous dispersion having a solid content of 75% by mass was obtained.

(Preparation of coating liquid for easy adhesion layer P1)
The following raw materials were mixed to prepare a coating solution.
Water 40.61 mass%
Isopropanol 30.00% by mass
Polyester water dispersion 11.67% by mass
Polyvinyl alcohol aqueous solution 15.00% by mass
Block isocyanate-based crosslinking agent 0.67% by mass
Particles (silica sol with an average particle diameter of 100 nm, solid content concentration 40% by mass)
1.25% by mass
Catalyst (organotin-based compound solid concentration 14% by mass) 0.30% by mass
Surfactant (silicon-based, solid content concentration 10% by mass) 0.50% by mass

(Polymerization of urethane resin used for easy adhesion layer P2)
A urethane resin containing an aliphatic polycarbonate polyol as a constituent component was prepared by the following procedure. In a four-necked flask equipped with a stirrer, Dimroth condenser, nitrogen inlet tube, silica gel drying tube, and thermometer, 43.75 parts by mass of 4,4-diphenylmethane diisocyanate, 12.85 parts by mass of dimethylolbutanoic acid, several 153.41 parts by mass of polyhexamethylene carbonate diol having an average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent were added and stirred at 75 ° C. for 3 hours in a nitrogen atmosphere. It was confirmed that had reached the predetermined amine equivalent. Next, after lowering the temperature of the reaction solution to 40 ° C., 8.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25 ° C., and the polyurethane prepolymer solution was added and dispersed while stirring and mixing water at 2000 min ^−1. It was. Thereafter, a part of acetone and water was removed from the mixed solution under reduced pressure to prepare a water-soluble polyurethane resin having a solid content of 35%. The obtained glass transition temperature of the polyurethane resin containing the aliphatic polycarbonate polyol as a constituent component was −30 ° C.

(Polymerization of oxazoline-based crosslinking agent used in easy-adhesion layer P2)
In a flask equipped with a thermometer, a nitrogen gas inlet tube, a reflux condenser, a dropping funnel, and a stirrer, a mixture of 58 parts by mass of ion-exchanged water and 58 parts by mass of isopropanol as an aqueous medium, and a polymerization initiator (2, 4 parts by mass of 2′-azobis (2-amidinopropane) dihydrochloride) was added. Meanwhile, in the dropping funnel, 16 parts by mass of 2-isopropenyl-2-oxazoline as a polymerizable unsaturated monomer having an oxazoline group, methoxypolyethylene glycol acrylate (average number of moles of ethylene glycol added: 9 mol, Shin-Nakamura Chemical Made) A mixture of 32 parts by mass and 32 parts by mass of methyl methacrylate was added and added dropwise at 70 ° C. for 1 hour in a nitrogen atmosphere. After completion of the dropwise addition, the reaction solution was stirred for 9 hours and cooled to obtain a water-soluble resin having an oxazoline group having a solid concentration of 40% by mass.

(Preparation of coating solution for easy adhesion layer P2)
The following raw materials were mixed to prepare a coating solution for forming a coating layer excellent in adhesion with the functional layer.
Water 55.62% by mass
Isopropanol 30.00% by mass
Polyurethane resin 11.29% by mass
Oxazoline-based crosslinking agent aqueous solution 2.26% by mass
Particles (silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.71% by mass
Particles (silica sol with an average particle diameter of 450 nm, solid content of 40% by mass)
0.07% by mass
Surfactant (silicone, solid concentration 100% by mass) 0.05% by mass

<Manufacture of polyester resin for base film>
(Production Example 1-Polyester X)
When the temperature of the esterification reactor was raised to 200 ° C., 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were charged, and 0.017 parts by mass of antimony trioxide as a catalyst while stirring. 0.064 parts by mass of magnesium tetrahydrate and 0.16 parts by mass of triethylamine were charged. Next, the pressure was raised and the pressure esterification reaction was carried out under conditions of a gauge pressure of 0.34 MPa and 240 ° C., then the esterification reaction can was returned to normal pressure, and 0.014 part by mass of phosphoric acid was added. . Furthermore, it heated up to 260 degreeC over 15 minutes, and 0.012 mass part of trimethyl phosphate was added. Then, after 15 minutes, dispersion treatment was performed with a high-pressure disperser, and after 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can and subjected to polycondensation reaction at 280 ° C. under reduced pressure.

After completion of the polycondensation reaction, it is filtered through a NASRON filter with a 95% cut diameter of 5 μm, extruded into a strand from a nozzle, and cooled and solidified using cooling water that has been filtered (pore diameter: 1 μm or less) in advance. And cut into pellets. The obtained polyethylene terephthalate resin (X) had an intrinsic viscosity (inherent viscosity) of 0.68 dL / g, and contained substantially no inert particles or internal precipitation particles (hereinafter, polyethylene terephthalate resin (X) was added). (Abbreviated as PET (X)).

(Production Example 2-Polyester Y)
Mix 10 parts by weight of the dried UV absorber (2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazinon-4-one) and 90 parts by weight of PET (X). Then, a polyethylene terephthalate resin (Y) containing an ultraviolet absorber was obtained using a kneading extruder (hereinafter, polyethylene terephthalate resin (Y) is abbreviated as PET (Y)).

(Manufacture of base film)
As a raw material for the base film intermediate layer, 90 parts by mass of PET (X) resin pellets containing no particles and 10 parts by mass of PET (Y) resin pellets containing an ultraviolet absorber were dried under reduced pressure at 135 ° C. for 6 hours (1 Torr ) And then supplied to the extruder 2 (for the intermediate layer II layer), and PET (X) was dried by a conventional method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III). And dissolved. After filtering these two kinds of polymers with a filter medium made of a sintered stainless steel (nominal filtration accuracy of 10 μm particles 95% cut), laminating them in a two-kind / three-layer confluence block, and extruding them into a sheet form from a die, The film was wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method, and cooled and solidified to produce an unstretched film. At this time, the discharge amount of each extruder was adjusted so that the ratio of the thickness of the I layer, the II layer, and the III layer was 10:80:10.

Next, P1 coating on one side of the unstretched PET film and P2 coating solution on the other side were applied by a reverse roll method so that the coating amount after drying was 0.12 g / m ² , and then led to a dryer. Dry at 20 ° C. for 20 seconds.

The unstretched film on which the coating layer was formed was guided to a tenter stretching machine, guided to a hot air zone at a temperature of 135 ° C. while being gripped by a clip, and stretched 3.8 times in the width direction. Next, while maintaining the width stretched in the width direction, the film was treated at a temperature of 225 ° C. for 30 seconds, and then both ends of the film cooled to 130 ° C. were cut with a shear blade, and a tension of 0.5 kg / mm ² was obtained. After cutting off the ear part, it was wound up to obtain a uniaxially oriented PET film (TD) having a film thickness of 70 μm. The intrinsic viscosity of the entire film was 0.65 dL / g. The properties of the obtained uniaxially oriented PET film (TD) are shown in Table 1.
The direction of the orientation principal axis (slow axis) of a total of five points of the both ends in the longitudinal direction of the obtained film, the intermediate part, and the intermediate part corresponding to the middle between the end part and the central part was measured. The orientation main axis was a direction orthogonal to the longitudinal direction, and the angle between the orientation main axis and the direction orthogonal to the longitudinal direction was 0 degree on an average of 5 points and 5 degrees at the maximum among 5 points.

The unstretched film obtained in the same manner was heated to 105 ° C. using a heated roll group and an infrared heater, and then stretched 4 times in the running direction by a roll group having a difference in peripheral speed. Then, after applying the P1 coating solution on one side of the PET film stretched in the longitudinal direction by the reverse roll method so that the coating amount after drying is 0.12 g / m ² , a tenter stretching machine The film was held at a temperature of 135 ° C. while maintaining the width, then dried at a temperature of 135 ° C., then treated at a temperature of 220 ° C. for 30 seconds, cooled to 130 ° C., and uniaxially oriented to a film thickness of 70 μm. A PET film (MD) was obtained. The characteristics of the obtained uniaxially oriented PET film (MD) are shown in Table 1.
The orientation principal axis of the obtained film was the longitudinal direction, and the angle between the orientation principal axis and the longitudinal direction was 0 degree on an average of 5 points and 1 degree at the maximum among 5 points.

(Lamination of hard coat layer)
95 parts by mass of urethane acrylate hard coating agent (Arakawa Chemical Industries, Beamset (registered trademark) 577, solid content concentration 100%), photopolymerization initiator (BASF Japan, Irgacure (registered trademark) 184, solid content Concentration 100%) 5 parts by mass and leveling agent (BYK307, BYK307, solid content concentration 100%) 0.1 part by mass are mixed and diluted with a solvent of toluene / MEK = 1/1 to obtain a concentration. A 40% coating solution was prepared.
Using a Mayer bar on the surface of the easy-adhesion layer P2 of the base film, the hard coat coating solution is applied so that the film thickness after drying is 5.0 μm, dried at 80 ° C. for 1 minute, and then irradiated with ultraviolet rays. (Integrated light quantity 200 mJ / cm ² ).

(Laminated polarizer)
The following four methods were performed as methods for providing a polarizer on the base film.
(A) A method of providing a rubbing alignment layer on a substrate film and providing a polarizing film comprising a liquid crystal compound and a dichroic dye thereon (polarizer lamination method A)
(B) A method in which a photo-alignment layer is provided on a base film, and a polarizing film comprising a liquid crystal compound and a dichroic dye is provided thereon (polarizer lamination method B)
(C) A method in which a polarizing film made of PVA / iodine is provided on a thermoplastic substrate and then transferred to the substrate film (polarizer lamination method C).
(D) A method of creating a polarizing film made of PVA / iodine and bonding it to a base film (polarizer lamination method D)
Details of each method will be described below.

Polarizer lamination method A
(Formation of rubbing alignment layer)
A rubbing alignment layer coating material having the following composition was applied to the easy adhesion layer P1 surface of the base film using a bar coater, and dried at 120 ° C. for 3 minutes to form a film having a thickness of 200 nm. Subsequently, the surface of the obtained film was treated with a rubbing roll wound with a nylon brushed cloth to obtain a base film on which a rubbing alignment layer was laminated. The rubbing direction was set to 0 °, 45 °, or 90 ° with respect to the longitudinal direction of the film.

Paint for rubbing alignment layer Completely saponified polyvinyl alcohol Molecular weight 800 2 parts by weight Ion-exchanged water 100 parts by weight

(Synthesis of polymerizable liquid crystal compounds)
The description of paragraph [0134] of JP-T-2007-510946 and Lub et al. Recl. Trav. Chim. With reference to Pays-Bas, 115, 321-328 (1996), a compound (A) represented by the following formula (1) and a compound (B) represented by the following formula (2) were synthesized.

With reference to Example 1 of JP-A-63-301850, a dye (c) represented by the following formula (3) was synthesized.

A dye (d) represented by the following formula (4) was synthesized with reference to Example 2 of JP-B-5-49710.

A dye (e) represented by the following formula (5) was synthesized with reference to the method for producing the compound of the general formula (1) described in JP-B 63-1357.

(Formation of polarizing film)
Compound (I) 75 parts by mass, Compound (b) 25 parts by mass, Dye (c) 2.5 parts by mass, Dye (d 2.5 parts by mass, Dye (e) 2.5 parts by mass, Irgacure (registered trademark) A polarizing film paint consisting of 6 parts by weight of 369E (BASF) and 250 parts by weight of orthoxylene was applied on a base film laminated with a rubbing alignment layer using a bar coater and dried at 110 ° C. for 3 minutes. Then, a film having a thickness of 2 μm was formed, and subsequently UV light was irradiated to provide a polarizer on the substrate film.

Polarizer lamination method B
(Synthesis of paint for photo-alignment layer)
Based on the description in Example 1, Example 2, and Example 3 of JP 2013-33248 A, a 5% by mass solution of a polymer (f) represented by the following formula (6) in cyclopentanone is produced. did.

(Formation of photo-alignment layer)
The coating material for photo-alignment layers having the above composition was applied to one side of the base film using a bar coater and dried at 80 ° C. for 1 minute to form a film having a thickness of 150 nm. Subsequently, polarized UV light was irradiated to obtain a base film on which a photo-alignment layer was laminated. The polarization direction of the UV light was 45 degrees with respect to the longitudinal direction of the film.
The above-mentioned coating material for polarizing film was applied on the photo-alignment layer, and the polarizing layer was provided on the base film on which the alignment layer was laminated in the same manner.

Polarizer lamination method C
(Manufacture of substrate laminated polarizer)
An unstretched film having a thickness of 100 μm was prepared using polyester X as a thermoplastic resin substrate, and an aqueous solution of polyvinyl alcohol having a polymerization degree of 2400 and a saponification degree of 99.9 mol% was applied to one side of the unstretched film and dried. Thus, a PVA layer was formed.
The obtained laminate was stretched twice in the longitudinal direction between rolls having different peripheral speeds at 120 ° C. and wound up. Next, the obtained laminate was treated with a 4% boric acid aqueous solution for 30 seconds, and then immersed in a mixed aqueous solution of iodine (0.2%) and potassium iodide (1%) for 60 seconds. Staining was followed by treatment with a mixed aqueous solution of potassium iodide (3%) and boric acid (3%) for 30 seconds.
Further, this laminate was uniaxially stretched in the longitudinal direction in a mixed aqueous solution of boric acid (4%) and potassium iodide (5%) at 72 ° C. The stretched laminate was subsequently washed with a 4% aqueous potassium iodide solution, the aqueous solution was removed with an air knife, dried in an oven at 80 ° C., slitted at both ends, wound up, 30 cm wide and 1000 m long. The base material laminated polarizer 1 was obtained. The total draw ratio was 6.5 times, and the thickness of the polarizer was 5 μm. The thickness was read by embedding the base material laminated polarizer 1 in an epoxy resin, cutting out a section, and observing with an optical microscope.

(Lamination of polarizing layer)
After coating the substrate film with an ultraviolet curable acrylic adhesive, the polarizer surface of the substrate laminate polarizer 1 is bonded, and ultraviolet rays are irradiated from the substrate laminate polarizer 1 side to the substrate film. The substrate laminated polarizer 1 was laminated. Thereafter, the thermoplastic resin substrate was peeled off, and a polarizer was provided on the substrate film.

Polarizer lamination method D
(Manufacture of single-layer polarizer)
A polyvinyl alcohol resin film having a saponification degree of 99.9% was guided to a roll having a difference in peripheral speed, and uniaxially stretched three times at 100 ° C. The obtained stretched polyvinyl alcohol stretched film is dyed in a mixed aqueous solution of potassium iodide (0.3%) and iodine (0.05%), and then in a 10% aqueous solution of boric acid at 72 ° C. The film was uniaxially stretched 8 times. Thereafter, it was washed with ion-exchanged water, further immersed in a 6% potassium iodide aqueous solution, the aqueous solution was removed with an air knife, and dried at 45 ° C. to obtain a polarizer. The thickness of the polarizer was 18 μm.

(Laminated polarizer)
After coating the substrate film with an ultraviolet curable acrylic adhesive, a single-layer polarizer was bonded, and ultraviolet rays were irradiated from the substrate-laminated polarizer side to provide a polarizer on the substrate film.

(Lamination of retardation layer)
The following four methods were performed as a method of providing the retardation layer on the polarizer.
(F) Method of providing a 1/2 wavelength layer and a 1/4 wavelength layer on a polarizer by coating (Lamination method F of retardation layer)
(G) A method of transferring a ½ wavelength layer provided on a release film onto a polarizer, and further transferring a ¼ wavelength layer provided on the release film thereon (laminating method of retardation layer) G)
(H) A method of providing a quarter wavelength layer and a half wavelength layer on a release film, and transferring the layer onto a polarizer (layering method H of retardation layer)
(I) Method of providing a ½ wavelength layer on a ¼ wavelength layer by coating, and bonding the ½ wavelength layer surface to a polarizer (Lamination method I of retardation layer)
Details of each method will be described below.

Lamination method F of retardation layer
Polyvinyl alcohol (polyvinyl alcohol 1000 fully saponified 2% by weight aqueous solution (surfactant 0.2%) is applied onto a polarizer provided on a base film, dried, and dried to a thickness of about 100 nm. Subsequently, the surface of the polyvinyl alcohol film was rubbed so that the rubbing angle was 15 degrees with respect to the absorption axis of the polarizer.
Subsequently, a retardation layer forming solution having the following composition was applied to the surface subjected to the rubbing treatment by a bar coating method. The applied film was dried and subjected to orientation treatment, and then cured by irradiating with ultraviolet rays to form a ½ wavelength layer.
Phase difference layer forming solution LC242 (manufactured by BASF) 75 parts by mass The following compound 20 parts by mass

Trimethylolpropane triacrylate 5 parts by weight Irgacure 379 3 parts by weight Surfactant 0.1 part by weight Methyl ethyl ketone 250 parts by weight

Subsequently, a polyvinyl alcohol film was similarly provided on the ½ wavelength layer, and a rubbing treatment was performed. The rubbing treatment angle was set to 73 degrees with respect to the absorption axis of the polarizer. The retardation layer forming solution was applied by a bar coating method, dried, subjected to an alignment treatment, and then cured by irradiation with ultraviolet rays. In the bar coat, the thickness was adjusted to be a quarter wavelength layer.

Lamination method G of retardation layer
A biaxially stretched polyethylene terephthalate (PET) film having a thickness of 50 μm was rubbed. A solution for forming a retardation layer is applied to the rubbing surface by a bar coating method, dried, subjected to an alignment treatment, cured by irradiation with ultraviolet rays, and a ½ wavelength layer on a biaxially stretched polyethylene terephthalate film. Was established. Next, the 1/2 wavelength layer surface and the polarizer surface provided in the base film were bonded together using the ultraviolet curing adhesive. Thereafter, the biaxially stretched PET film was peeled off. The bonding was performed so as to be 15 degrees with respect to the absorption axis of the polarizer.
In the same manner, a quarter wavelength layer was provided on a biaxially stretched PET film and bonded to the previous half wavelength layer using an optical transparent adhesive sheet. The bonding was performed so as to be 75 degrees with respect to the absorption axis of the polarizer.

Lamination method H of retardation layer
A biaxially stretched polyethylene terephthalate (PET) film having a thickness of 50 μm was rubbed. A solution for forming a retardation layer is applied to the rubbing surface by a bar coating method, dried, subjected to an orientation treatment, cured by irradiation with ultraviolet rays, and a quarter wavelength layer on a biaxially stretched polyethylene terephthalate film. Was established. Furthermore, polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified 2% by weight aqueous solution (surfactant 0.2%) was applied onto the quarter wavelength layer and dried to obtain a polyvinyl alcohol film having a thickness of about 100 nm. Subsequently, the surface of the polyvinyl alcohol film was rubbed, and the PVA rubbed surface was coated with a retardation layer forming solution by a bar coating method, dried, subjected to an alignment treatment, and then irradiated with ultraviolet rays. A half-wave layer was provided, and the angle between the rubbing direction when the quarter-wave layer was provided and the rubbing direction when the half-wave layer was provided was set to 60 degrees. Furthermore, the half-wave layer surface and the polarizer surface provided on the base film were bonded together using an ultraviolet curable adhesive, and then the biaxially stretched PET film was peeled off. The absorption axis, is 15 degrees the rubbing direction of the 1/2-wavelength layer, the rubbing direction of the 1/4 wavelength layer is made to be 75 degrees.

Lamination method I of retardation layer
The quarter-wave film was unwound from a roll of quarter-wave film having a slow axis in the length direction, cut to the required length, and the surface was rubbed. A half-wave layer was provided on the rubbing-treated surface by the same method as the retardation layer laminating method F. Furthermore, the 1/2 wavelength layer surface and the polarizer surface provided in the base film were bonded together using the ultraviolet curable adhesive. The quarter-wave film was made by extruding a propylene-ethylene random copolymer (ethylene content 5%) into a sheet and stretching it with a roll in the length direction (thickness 20 μm). The lamination was performed such that the absorption axis of the polarizer and the rubbing direction of the ½ wavelength layer were 15 degrees, and the slow axis direction of the ¼ wavelength layer was 75 degrees.

In addition, the thickness of the retardation layer by said coating was 1.2 micrometers in the 1/4 wavelength layer, and 2.3 micrometers in the 1/2 wavelength layer. The thickness of the adhesive layer was 3 μm.

Examples 1-18
A circularly polarizing plate was prepared by providing a polarizer and a retardation layer on the base film shown in Table 2 by the method shown in Table 2.

Comparative Example 1
After laminating a polarizer on the substrate film by the polarizer laminating method D, a TAC film having a thickness of 80 μm was adhered on the polarizer using a PVA adhesive to prepare a polarizing plate. Further, a retardation layer was provided on the TAC film of the polarizing plate by the retardation layer laminating method I to prepare a circularly polarizing plate.

Comparative Example 2
After laminating a polarizer on the substrate film by the polarizer laminating method A, a 1/2 wavelength film was laminated on the polarizer, and a 1/4 wavelength film was further laminated thereon. The half-wave film was obtained by doubling the thickness of the quarter-wave film, and each lamination was performed according to the lamination method I of the retardation layer. The half-wave plate was set to 15 degrees with respect to the absorption axis of the polarizer, and the quarter-wave layer was set to 75 degrees with respect to the absorption axis of the polarizer.

Table 2 shows the characteristics of the circularly polarizing plates obtained in Examples 1 to 18 and Comparative Examples 1 and 2. In all cases, the antireflection effect was good. In addition, when the EL display device used when the antireflection effect was evaluated was visually observed without using polarized sunglasses, the EL display device having the circularly polarizing plate of each example showed rainbow spots. Good visibility was obtained.

Furthermore, Table 3 shows the flexibility characteristics of the circularly polarizing plates obtained in Examples 1 to 18 and Comparative Examples 1 and 2.

(Creation of paint for circularly polarized reflective layer)
A methyl ethyl ketone / cyclohexanone (95/5 mass ratio) solution having a solid content concentration of 5% having the following composition was prepared.
・ LC242 (manufactured by BASF) 100 parts by mass ・ LC756 (manufactured by BASF) 5 parts by mass ・ 4 parts by mass of Irgacure 819 ・ 0.75 parts by mass of the following fluorine-containing compound (1)

・ Fluorine-containing compound (2) below 0.075 parts by mass

(Formation of circularly polarized reflective layer)
The circularly polarizing reflective layer coating material was applied to the retardation layer surface of the circularly polarizing plate obtained in the example with a bar coater and dried at 85 ° C. Subsequently, ultraviolet rays were irradiated in an oven at 85 ° C. to provide a circularly polarized light reflection layer.

(Evaluation of a circularly polarizing plate with a circularly polarizing reflective layer)
The circularly polarizing plate laminated with the circularly polarizing reflective layer obtained above was similarly incorporated into an EL display and observed with the naked eye. As a result, the luminance was higher than that of the circularly polarizing plate of each example in which the circularly polarizing reflective layer was not laminated. The improvement effect was recognized.
Similarly, when the handling property and the bending resistance were evaluated, both were at the same level as the original examples.

The EL display device of the present invention uses a base film having a specific in-plane retardation, and the number of self-supporting films existing between the polarizer and the retardation layer is 1 or less, and 1 / Since a circularly polarizing plate having a two-wavelength layer and a quarter-wavelength layer is used, it is excellent in visibility (inhibition of rainbow unevenness), can be thinned, and trouble does not easily occur in the manufacturing process.
In addition, in the case of a flexible EL display device, even when it is repeatedly bent or left in a high temperature state, the stacked members are not easily peeled off and are not easily marked.
Furthermore, when a polyester film is used as the base film of the circularly polarizing plate, an EL display device having a circularly polarizing plate excellent in moisture permeability, dimensional stability, mechanical strength, and chemical stability is provided. Can do.

Claims (4)

1. An electroluminescence display device comprising an electroluminescence cell, and a circularly polarizing plate disposed on the viewing side of the electroluminescence cell,
   The circularly polarizing plate has, in order, a retardation layer, a polarizer, and a base film,
   (1) The in-plane retardation of the base film is 3000 to 30000 nm,
   (2) There is no self-supporting film between the polarizer and the retardation layer, or there is only one film (here, the retardation layer itself is included between the polarizer and the retardation layer), and (3) The electroluminescence display device in which the retardation layer has a ½ wavelength layer and a ¼ wavelength layer.
2. The electroluminescent display device according to claim 1, wherein the polarizer has a thickness of 12 μm or less.
3. The electroluminescent display device according to claim 1 or 2, wherein the polarizer comprises a polymerizable liquid crystal compound and a dichroic dye.
4. The electroluminescence display device according to any one of claims 1 to 3, wherein at least one of the ½ wavelength layer and the ¼ wavelength layer is made of a liquid crystal compound.