TW201940324A - 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 invention relates to an electroluminescence (EL) display device.

In the EL display device, external light is reflected on the surface of a constituent material such as an image display unit, a touch sensor, and the wiring portion, etc., and there is a problem that visibility is reduced. For these problems, a method has been proposed in which an optical laminate is arranged on the exit surface of the image display device to reduce the reflection of external light. This optical laminated body generally uses a circular polarizing plate in which a linear polarizing plate and a 1/4 wavelength retardation plate are laminated.

As a polarizer protective film for a polarizing plate, a polyester film with an in-plane retardation of 3000 to 30,000 nm has been proposed (for example, refer to Patent Document 1). Compared with cellulose or acrylic films, polyester films are suitable because they have low moisture permeability, excellent mechanical properties (high impact resistance and high coefficient of elasticity), and excellent chemical properties (solvent resistance, etc.). For image display devices. However, polyester films have the disadvantage that they are prone to iridescence because they have birefringence. Therefore, when a polyester film is used, in order to suppress iridescence and provide sufficient in-plane retardation, it is necessary to increase the film thickness.

Furthermore, in order to suppress the influence of the wavelength dispersion of the refractive index and obtain a circularly polarizing plate with better color reproducibility, a technique has been proposed in which a 1/4 wavelength plate and a 1/2 wavelength plate are combined (Patent Document 2). However, in the case where a plurality of such retardation plates are laminated on a polarizing plate, the above-mentioned thickness problem becomes more significant. In addition, since a circularly polarizing plate has a plurality of films laminated, the circularly polarizing plate is rolled and stored in a manufacturing step, which is likely to cause curling, and it is difficult to handle it in the subsequent step of bonding with an EL unit. Situation. In particular, in a large-scale image display device of more than 40 types (the diagonal length of the display portion is 40 inches), the circular polarizing plate also becomes large, and the problem of curling easily occurs.

In recent years, as an image display device, a flexible EL display device has been proposed, which has a wide screen and can be folded into a V-shape, a Z-shape, a W-shape, a double-open shape, or the like when being carried, or can be rolled into a tube . If a circular polarizing plate is used in such a foldable or rollable EL display device, sufficient flexibility cannot be obtained due to its thickness, and it may be repeatedly bent or placed in a car. In the case of a high temperature, there are problems that the film is easily peeled off and creases are easily generated.

Prior art literature Patent literature

Patent Document 1 Japanese Patent Application Publication No. 2012-256057

Patent Document 2 Japanese Unexamined Patent Publication No. 10-68816

The present invention has been completed with the background of such a problem of the conventional technology. That is, the object of the present invention is to provide an EL display device which can ensure visibility and thinness, and is unlikely to cause problems in the manufacturing steps. In the case of a flexible EL display device, even if it is repeatedly bent or placed in In the case of a high temperature state, the laminated members are not easily peeled from each other, and it is also difficult to generate creases.

The inventor of the present case has developed laminated components in order to develop thin components that ensure visibility and are thin, and are less likely to cause problems in the manufacturing process. In the case of a flexible EL display device, even when repeatedly bent or placed in a high temperature state, EL display devices that are not easily peeled from each other and are not prone to creases. As a result of detailed research, it was found that a substrate film having a specific in-plane retardation is used, and a self-supporting film existing between a polarizer and a retardation layer The number of lenses is one or less, and a circularly polarizing plate having a 1 / 2-wavelength layer and a 1 / 4-wavelength layer is used as the retardation plate. The present invention has been completed based on such knowledge.

That is, the present invention relates to the EL display device shown in items 1 to 4.

     Item 1     

An electroluminescence display device is provided with an electroluminescence unit and an electroluminescence display device arranged on a circular polarizing plate closer to a viewing side than the electroluminescence unit, characterized in that the circular polarizing plate, It has a retardation layer, a polarizer, and a base film in order, (1) the in-plane retardation of the base film is 3000 to 30,000 nm, and (2) there is no self-supporting film between the polarizer and the retardation layer, or only There is one (here, between the polarizer and the retardation layer, and also includes the retardation layer itself), and (3) the retardation layer has a 1/2 wavelength layer and a 1/4 wavelength layer.

     Item 2     

The electroluminescent display device according to the above item 1, wherein the thickness of the polarizer is 12 μm or less.

     Item 3     

The electroluminescent display device according to the above item 1 or 2, wherein the polarizer includes a polymerizable liquid crystal compound and a dichroic dye.

     Item 4     

The electroluminescent display device according to any one of the above items 1 to 3, wherein at least one of the half-wavelength layer and the quarter-wavelength layer includes a liquid crystal compound.

In the EL display device of the present invention, a substrate film having an in-plane retardation of 3000 to 30,000 nm is used, and the number of self-supporting films existing between the polarizer and the retardation layer is 1 or less. The circularly polarizing plates of the two-wavelength layer and the 1 / 4-wavelength layer serve as retardation layers, so they have excellent visibility (suppression of iridescent spots), can be thinned, and are less prone to problems during manufacturing steps.

Moreover, in the case of a flexible EL display device, even when repeatedly folded or placed in a high-temperature state, the laminated members are not easily peeled from each other, and creases are hardly generated.

Forms used to implement the invention

An EL display device of the present invention includes: an EL unit; and a circularly polarizing plate, which is disposed closer to a viewing side than the EL unit. By arranging a circularly polarizing plate on the viewing surface of the EL display device, it is possible to reduce a decrease in visibility due to external light reflected on the surface of the EL unit or wiring. The EL display device of the present invention is thin. The circular polarizing plate has a retardation layer, a polarizer, and a base film in this order.

First, a circular polarizing plate used in the present invention will be described. The circular polarizer has a retardation layer, a polarizer, and a base film in this order. In this circular polarizing plate, the retardation layer, the polarizer, and the base film are basically laminated in this order, but also include the concept of the presence of other layers between the layers.

    [A. Circular polarizer]         Substrate film    

First, the base film of a circularly polarizing plate is demonstrated. This circularly polarizing plate has a base film on the viewing side of a polarizer.

    (Material of base film)    

The resin as the base film used in the present invention is not particularly limited as long as it is birefringent that can be oriented, and can be used. From the viewpoint of increasing the hysteresis, polyester, polycarbonate, polystyrene, and the like are preferred, and polyester is more preferred. Preferred polyesters include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polyethylene naphthalate. Diester (PEN) and the like, more preferably PET and PEN. By using a polyester film as a base film, an EL display device having a circular polarizing plate having excellent moisture permeability resistance, dimensional stability, mechanical strength, and chemical stability can be obtained.

In the case of PET, the limiting 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, even 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, and even more preferably 1 dL / g. When the IV of PET is less than 0.58 dL / g, creases are likely to occur during repeated bending. When the IV of PET exceeds 1.5 dL / g, it may be difficult to form a film. In addition, as the limiting viscosity (IV) in the present invention, a mixture of phenol and 1,1,2,2-tetrachloroethane was used as a solvent at a mass ratio of 6: 4 and measured at a temperature of 30 ° C. value.

The transmittance of the base film at a wavelength of 380 nm is preferably less than 20%. The light transmittance at a wavelength of 380 nm is more preferably 15% or less, even more preferably 10% or less, and particularly preferably 5% or less. When the light transmittance is 20% or less, the iodine or the dichroic dye in the polarizer can be prevented from being deteriorated by ultraviolet rays. In addition, the transmittance in the present invention is measured in a vertical direction with respect to the plane of the film, and can be measured using a spectrophotometer (for example, Hitachi U-3500).

By adding a UV absorber to the base film, coating the coating liquid containing the UV absorber on the surface of the base film, and appropriately adjusting the type or concentration of the UV absorber and the thickness of the base film, etc. The light transmittance at a wavelength of 380 nm is made 20% or less. In the present invention, a substance known in this technical field can be used as an ultraviolet absorbent. Examples of the ultraviolet absorber include an organic ultraviolet absorber and an inorganic ultraviolet absorber. From the viewpoint of transparency, an organic ultraviolet absorber is preferred.

The organic ultraviolet absorber is not particularly limited as long as the light transmittance of the base film at a wavelength of 380 nm is 20% or less, and it can be used. Examples of such an organic ultraviolet absorber include benzotriazole-based, benzophenone-based, cyclic imide-based and the like, and combinations thereof.

In order to improve smoothness, it is preferable to add particles having an average particle diameter of 0.05 to 2 μm to the base film. Examples of the particles include titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silicon dioxide, aluminum oxide, talc, kaolinite, clay, calcium phosphate, mica, lithium bentonite, zirconium dioxide, tungsten oxide, and fluoride Inorganic particles such as lithium and calcium fluoride; styrene-based, acrylic-based, melamine-based, benzoguanidine Organic polymer particles such as benzoguanamine and polysiloxane. The average particle diameter is calculated by a method of observing particles of a film cross section by a scanning electron microscope. Specifically, 100 particles in 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 of these was used as the average particle diameter.

Such particles can be added to the entire base film. Alternatively, the base material may be a co-extruded multilayer structure of skin-core, and particles are added only in the skin layer.

    (In-plane hysteresis of the base film)    

The base film has an in-plane hysteresis of 3000 to 30,000 nm. One of the characteristics of the EL display device of the present invention is to use a film having an in-plane retardation of 3000 to 30,000 nm as a base film of a circularly polarizing plate. If the in-plane hysteresis of the base film is less than 3000 nm, when viewed from an oblique direction relative to the normal direction, good visibility may not be ensured. In addition, in order to prevent a black screen or coloring from occurring when viewing an image while wearing polarized sunglasses, if the in-plane retardation of the base film is less than 3000 nm, rainbow spots may be observed. The lower limit of the preferable in-plane hysteresis is 4500 nm, and the lower limit is more preferably 6000 nm.

On the other hand, the upper limit of the in-plane hysteresis is preferably 30,000 nm. If the base film has a hysteresis exceeding this value, not only can the effect of further improving the visibility not be substantially obtained, but the thickness of the base film becomes considerably thicker, which reduces the operability as an industrial material. The upper limit of the in-plane hysteresis is more preferably 15,000 nm or less, still more preferably 11,000 nm, and particularly preferably 9000 nm or less, from the viewpoint of reducing the thickness of the film to ensure thinness or flexibility.

The hysteresis of the base film can be obtained by measuring the refractive index and thickness in the biaxial direction, and can also be obtained using a commercially available automatic birefringence measuring device such as KOBRA-21ADH (Oji scientific instruments Co., Ltd.). The refractive index is a value measured from the wavelength of the sodium D line (589 nm).

In the base film, the ratio of the in-plane retardation (Re) to the thickness direction retardation (Rth) is preferably within a specific range. The retardation in the thickness direction refers to the average of the retardation obtained by multiplying the two birefringences (ΔNxz and ΔNyz) by the film thickness d when the film is viewed from the thickness direction section. The smaller the difference between the in-plane hysteresis and the thickness direction hysteresis, the more the isotropy can be increased by the effect of birefringence caused by the observation angle, so the hysteresis change caused by the observation angle becomes smaller. Therefore, it is considered that it is not easy to produce iridescent stains due to the observation angle.

The ratio (Re / Rth) of the in-plane retardation to the thickness-direction retardation of the base film is preferably 0.2 or more, more preferably 0.5 or more, and even more preferably 0.6 or more. The larger the ratio (Re / Rth) of the in-plane hysteresis to the thickness direction hysteresis, the more the effect of birefringence can increase the isotropy, and it is not easy to produce an iridescent color spot due to the observation angle. Further, in a completely uniaxial (uniaxially symmetric) film, the ratio (Re / Rth) of the in-plane retardation to the thickness-direction retardation is two. However, as described above, the mechanical strength in the direction orthogonal to the orientation direction is significantly reduced as the film is almost completely uniaxial (uniaxially symmetric).

On the other hand, the ratio (Re / Rth) of the in-plane retardation to the thickness-direction retardation of the base film is preferably 1.5 or less, more preferably 1.2 or less, and even more preferably 1 or less. In order to completely suppress the occurrence of iridescent spots due to the observation angle, the ratio (Re / Rth) of the in-plane hysteresis to the thickness direction retardation does not need to be 2, but it is sufficient that it is 1.5 or less or 1.2 or less. In addition, even if the ratio is less than or equal to 1, the viewing angle characteristics (180 degrees left and right, and 120 degrees above and below) required by the EL display device can be sufficiently satisfied.

    (Nz coefficient)    

In the base film, the Nz coefficient represented by | ny-nz | / | ny-nx | is preferably 1.7 or less. The Nz coefficient can be obtained in the following manner. The orientation axis direction of the film was obtained using a molecular orienter (manufactured by Oji Scientific Instruments, MOA-6004 molecular orienter), and an Abbe refractometer (NAR-4T, manufactured by ATAGO, measuring wavelength: 589 nm). The biaxial refractive index (ny, nx, where ny> nx) and the thickness refractive index (nz) in the direction of the orientation axis and the direction orthogonal to it are obtained. Nx, ny, and nz thus obtained are brought into the formula represented by | ny-nz | / | ny-nx |, and the Nz coefficient can be obtained.

When the Nz coefficient of the base film exceeds 1.7, when the EL display device is viewed from an oblique direction, rainbow spots may be generated depending on the angle. The Nz coefficient is more preferably 1.65 or less, and even more preferably 1.63 or less. The lower limit of the Nz coefficient is 1.2. This is because it is technically difficult 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 even more preferably 1.45 or more.

    (Face orientation)    

In the substrate film, the degree of plane orientation represented by (nx + ny) / 2-nz is preferably below a specific value. Here, the values of nx, ny, and nz are obtained by the same method as the Nz coefficient. The surface orientation of the base film is preferably 0.13 or less, more preferably 0.125 or less, and even more preferably 0.12 or less. When the degree of plane orientation exceeds 0.13, when the EL display device is viewed obliquely, rainbow spots may be observed depending on the angle. If the degree of plane orientation is less than 0.08, the film thickness changes, and the hysteresis may become uneven in the plane of the film.

    (Manufacturing method of base film)    

The film to be a base material can be given a predetermined in-plane hysteresis by stretching. As long as properties are available, the extension may be uniaxial or biaxial. The slow axis of the base film may be a long side direction of the base film, a direction orthogonal to the long side direction, or an oblique direction. In addition, the long-side direction here means the direction of travel in the case of continuous production of a film. When the slow axis is the long side direction of the base film, the angle formed by the long side 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 of the base film is orthogonal to the long side direction, the angle formed by the long side direction and the slow axis of the base film is preferably 80 to 100 degrees, and particularly preferably 83 to 97 degrees. When the slow axis of the base film is oblique, the angle formed by the long side direction of the base film and the slow axis is preferably in the range of 35 to 55 degrees.

Taking a PET base film having a slow axis in a direction orthogonal to the long side direction as an example, the stretching conditions will be specifically described.

Both ends of the unstretched original film obtained by extruding the molten PET on a cooling roll are clamped by a jig and guided into a tenter. After preheating, the film is stretched in the lateral direction while being heated. In addition, continuous rolls may be stretched in the longitudinal direction before being stretched in the transverse direction. It is also possible to perform biaxial stretching at the same time. The longitudinal stretching temperature and the transverse stretching temperature are preferably 80 to 130 ° C, and particularly preferably 90 to 120 ° C. The longitudinal stretching ratio is preferably 1 to 3.5 times, and particularly preferably 1 to 3 times. The lateral extension ratio is preferably 2.5 to 6 times, and particularly preferably 3 to 5.5 times. In order to control the hysteresis in the above range, it is preferable to control the ratio of the longitudinal stretching magnification and the lateral stretching magnification. If the difference between the longitudinal and transverse stretching magnifications is too small, it is difficult to improve the hysteresis. In addition, setting the elongation temperature to a lower value is also a better countermeasure for increasing the hysteresis. In the subsequent heat treatment, the treatment temperature is preferably 100 to 250 ° C, and particularly preferably 180 to 245 ° C.

In order to obtain a base film having a slow axis in the long-side direction, it is preferable to perform longitudinal stretching with a continuous roll. Prior to the longitudinal extension step, lateral extension may also be performed.

In addition, the angle of the main orientation main axis of the substrate film and the long-side direction or an angle orthogonal to the long-side direction is preferably 20 degrees or less, more preferably 15 degrees or less, and even more preferably 10 degrees or less. It is preferably below 5 degrees. If the angle of the main orientation main axis of the substrate film to the long side direction or the direction orthogonal to the long side direction exceeds 20 degrees, when viewed through polarized sunglasses or the like, the brightness changes due to the angle. In addition, when extending in the long-side direction, the main orientation direction is the long-side direction, so it is the angle between the main orientation main axis and the long-side direction, while in the case of extending in the width direction, it is used as the main orientation main axis and the The angle of the side orthogonal direction.

The thickness of the substrate film is preferably 30 to 150 μm, more preferably 40 to 100 μm, and even more preferably 50 to 80 μm. When the thickness of the substrate film is less than 30 μm, it is difficult to achieve high in-plane hysteresis, and when it is more than 150 μm, it is difficult to handle thinning and flexibility in addition to being difficult to handle.

Corrosion treatment, flame treatment, and plasma treatment may be performed on the base film to improve adhesion.

    (Easy adhesion layer)    

On the base film, an easy-adhesion layer (easy-adhesion layer P1) may be provided in order to improve the adhesion between the polarizing film or the alignment layer described later.

Examples of the resin used in the easy-adhesion layer include polyester resins, polyurethane resins, polyester polyurethane resins, polycarbonate resins, polycarbonate polyurethane resins, Acrylic resins and the like are preferably polyester resins, polyester polyurethane resins, polycarbonate polyurethane resins, and acrylic resins. The easy-adhesive layer is preferably crosslinked. Examples of the crosslinking agent include isocyanate compounds, melamine compounds, epoxy resins, Oxazoline compounds, etc. In addition, in order to improve the adhesiveness, it is also useful to add a resin similar to the resin used in the alignment layer or the polarizing film, such as polyvinyl alcohol, polyimide, polyimide, and polyimide.

The easy-adhesion layer can be used as an aqueous coating material to which these resins, cross-linking agents, and particles according to demand are added, and can be applied and dried on a base film. Examples of the particles include those used in the aforementioned substrate.

The easy-adhesion layer can be set on the stretched substrate film in an off-line operation or in-line operation in a film-forming step. The easy-adhesion layer is preferably provided in a production line during the film forming step. In the case where the easy-adhesion layer is provided by the operation in the production line, it can be either before longitudinal extension or before transverse extension. Specially-applied water coating is applied just before horizontal extension, pre-heating and heating by a tenter, and drying and cross-linking in this heat treatment step, so as to set the easy-adhesive layer in the production line. . In addition, in the case where in-line coating is performed immediately before longitudinal stretching with a roller, it is preferred that the aqueous coating material is applied, and then dried with a vertical dryer before being guided to the stretching roller.

The coating amount of the water-based coating material 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 to provide functional layers such as a hard coat layer, an anti-reflection layer, a low-reflection layer, an anti-glare layer, and an antistatic layer on the opposite side of the base film from the surface on which the polarizing film is laminated.

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 even more preferably 1 to 10 μm. In addition, a plurality of such layers may be provided.

When a functional layer is provided, an easy-adhesion layer (easy-adhesion layer P2) may be provided between the functional layer and the base film. As the easy-adhesion layer P2, the resins, crosslinking agents, and the like listed in the above-mentioned easy-adhesion layer P1 can be appropriately used. 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 a production line operation. The easy-adhesion layer P1 and the easy-adhesion layer P2 can be formed by sequentially coating and drying. In addition, it is also preferable to apply the easy-adhesive layer P1 and the easy-adhesive layer P2 to both surfaces of the base film at the same time.

In addition, in the following description, a case where a substrate film is referred to includes not only a case where an easy adhesion layer is not provided, but also a case where an easy adhesion layer is provided. Similarly, those having a functional layer are also included in the base film.

    2. Polarizer    

In the circular polarizing plate used in the present invention, a polarizer is provided on the base film.

As the polarizer, for example, a polarizing film can be used. The polarizing film may be directly provided on the base film, or an orientation layer may be provided on the base film, and then a polarizing film may be provided thereon. In addition, in the present invention, a combination of an alignment layer and a polarizing film is collectively referred to as a polarizer. When a polarizing film is provided without providing an alignment layer on the base film, the polarizing film is sometimes referred to as a polarizer.

    (Polarizing film)    

The polarizing film has a function of passing polarized light in only one direction. The polarizing film is not particularly limited, and a coating film containing iodine or a dichroic dye in a stretched film such as polyvinyl alcohol (PVA), a dichroic dye film or a polymerizable liquid crystal compound, Polyene stretch films, wire grids, etc.

Among these, a polarizing film in which PVA adsorbs iodine and a polarizing film in which a dichroic dye is blended in a polymerizable liquid crystal compound are preferable examples.

First, a polarizing film that causes PVA to adsorb iodine will be described.

The polarizing film that makes PVA adsorb iodine can generally be immersed in a bath containing iodine and then uniaxially stretched, or immersed in a bath containing iodine, and then carried out in a boric acid bath. It is obtained by cross-linking treatment.

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 even more preferably 2 to 15 μm. If the thickness of the polarizing film is less than 1 μm, sufficient polarization characteristics cannot be exhibited, and if it is too thin, it may be difficult to handle. If the thickness of the polarizing film exceeds 30 μm, it cannot meet the purpose of ensuring thinness and flexibility.

In the case where a polarizing film that causes PVA to adsorb iodine and a base film are laminated, it is preferable that the base film and the polarizing film are bonded together. As the adhesive for bonding, a conventionally used adhesive can be used without limitation. Among them, preferred examples are PVA-based water-based adhesives, UV-curable adhesives, and the like, and more preferably UV-curable adhesives.

In this manner, for a polarizing film that allows PVA to adsorb iodine, a film that is a polarizer alone and a substrate film can be laminated. Or, it is also possible to use a laminated polarizer (release-supporting substrate laminated polarizer) on the release-supporting substrate by coating PVA on the release-supporting substrate and extending in this state, The polarizing film is then laminated to a substrate film. The method of laminating by this transfer is also the same as the above-mentioned bonding method, and can be preferably used as a method of laminating a polarizer and a base film. When this transfer method is used, the thickness of the polarizer is preferably 12 μm or less, more preferably 10 μm or less, even more preferably 8 μm or less, and particularly preferably 6 μm or less. Even this extremely thin polarizer is easy to handle because it has a release support substrate, and the polarizer can be easily laminated on the substrate film. By using such a thin polarizer, it is possible to further reduce the thickness and ensure flexibility.

In addition, a technique for laminating a polarizer and a base film is known, and for example, refer to Japanese Patent Application Laid-Open No. 2001-350021 and Japanese Patent Application Laid-Open No. 2009-93074.

A method of laminating a polarizer and a base film by transfer will be specifically described. First, PVA is coated on a release support substrate of a thermoplastic resin that is not extended or uniaxially extended perpendicularly to the long side direction, and then the laminate of the release support substrate of the obtained thermoplastic resin and the PVA is on the long side. It extends 2 to 20 times in the direction, preferably 3 to 15 times. The elongation temperature is preferably 80 to 180 ° C, and more preferably 100 to 160 ° C. Next, the stretched laminate is immersed in a bath containing a dichroic dye to adsorb the dichroic dye. Examples of the dichroic dye include iodine and organic dyes. When using iodine as a dichroic dye, it is preferable to use an aqueous solution containing iodine and potassium iodide as a dyeing bath. Next, it is immersed in an aqueous solution of boric acid for treatment, and washed with water and then dried. In addition, before the dichroic dye is adsorbed, it may be stretched 1.5 to 3 times as a pre-stretch. In addition, the method described above is an example, and adsorption of a dichroic dye may be performed before stretching, or treatment with boric acid may be performed before adsorption of a dichroic dye. Stretching can also be performed in a bath containing a dichroic dye or in a bath of an aqueous boric acid solution. These steps may be divided into a plurality of stages and combined.

As a release support substrate (release film) of a thermoplastic resin, polyester films such as polyethylene terephthalate, polyolefin films such as polypropylene and polyethylene, polyamide films, and polyamines can be used. Urethane film, etc. The peeling force can be adjusted with respect to a release support substrate (release film) of a thermoplastic resin by performing a corona treatment or providing a release coating layer, an easy-adhesion coating layer, or the like.

The polarizing mirror surface of the release-supporting substrate laminated polarizer is bonded to the substrate film with an adhesive or an adhesive, and then the release-supporting substrate is peeled off, thereby obtaining a laminated body of the substrate film and the polarizer. . The thickness of the adhesive is generally 5 to 50 μm, and the adhesive is 1 to 10 μm. In order to reduce the thickness, an adhesive is preferably used, and more preferably an ultraviolet curing adhesive is used. From the viewpoint that a special device is not required in the manufacturing process, it is preferable to use an adhesive.

Next, a polarizing film containing a dichroic dye in a polymerizable liquid crystal compound will be described.

A dichroic dye refers to a dye having the following properties: the absorbance of a molecule in the long axis direction is different from the absorbance in the short axis direction.

The dichroic dye preferably has a maximum absorption wavelength (λMAX) in a range of 300 to 700 nm. Examples of such a dichroic dye include an acridine dye, Organic dichroic dyes such as dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes. Among these, azo dyes are preferred. Examples of the azo dyes include monoazo dyes, diazo dyes, ginsazo dyes, azo dyes, and stilbene azo dyes. Among these, diazo dyes are preferred. And reference azo dyes. The dichroic dye can be used alone or in combination. In order to adjust the hue (no color), it is preferable to combine two or more types, and it is more preferable to combine three or more types. It is particularly preferred to use three or more azo compounds in combination.

Examples of preferred azo compounds include dyes described in Japanese Patent Application Laid-Open No. 2007-126628, Japanese Patent Application Laid-Open No. 2010-168570, Japanese Patent Application Laid-Open No. 2013-101328, and Japanese Patent Application Laid-Open No. 2013-210624. .

Among dichroic dyes, a dichroic dye polymer in which a side chain of a polymer such as acrylic acid is introduced is also a preferable form. Examples of such dichroic dye polymers include polymers listed in Japanese Patent Application Laid-Open No. 2016-4055 and polymers polymerized by compounds of [Chemical Formula 6] to [Chemical Formula 12] of Japanese Patent Application Publication No. 2014-206682. Polymer, etc.

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

The polarizing film also contains a polymerizable liquid crystal compound in order to improve film strength, polarization degree, and film homogeneity. In addition, the polymerizable liquid crystal compound also includes those that are used as a film after polymerization.

The polymerizable liquid crystal compound is a compound having a polymerizable group and exhibiting liquid crystallinity.

The polymerizable group refers to a group related to a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group capable of performing a polymerization reaction due to living radicals, acids, and the like generated from a photopolymerization initiator described later. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, a propenyloxy group, a methacryloxy group, an ethylene oxide group, and an oxygen group. Heterocyclobutane and the like. Among these, acryloxy, methacryloxy, ethyleneoxy, ethylene oxide, and oxetanyl are preferred, and acryloxy is more preferred. The compound exhibiting liquid crystal properties may be a thermotropic liquid crystal, a lyotropic liquid crystal, or 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 high-order smectic liquid crystal compound from the viewpoint of obtaining higher polarization characteristics. If the liquid crystal phase formed by the polymerizable liquid crystal compound is a higher-order smectic phase, a polarizing film with a higher degree of orientation order can be manufactured.

Specific examples of preferred polymerizable liquid crystal compounds include, for example, Japanese Patent Laid-Open No. 2002-308832, Japanese Patent Laid-Open No. 2007-16207, Japanese Patent Laid-Open No. 2015-163596, and Japanese Patent Laid-Open No. 2007-510946. , Japanese Unexamined Patent Publication No. 2013-114131, WO2005 / 045485, Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996) and the like.

From the viewpoint of improving the orientation of the polymerizable liquid crystal compound in the polarizing film, the content of the polymerizable liquid crystal compound is preferably 70 to 99.5% by mass, and more preferably 75 to 99% by mass. Even more preferably, it is 80 to 97% by mass, and particularly preferably 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.

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 cross-linking agent, etc. in addition to the polymerizable liquid crystal compound and the dichroic dye. .

Any solvent can be used as long as it can dissolve the polymerizable liquid crystal compound. Specific examples of the solvent include water; alcohol-based solvents such as methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, and cyrus; esters such as ethyl acetate, butyl acetate, and γ-butyrolactone Solvents; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, and 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 the polymerizable liquid crystal compound. The polymerization initiator is preferably a photopolymerization initiator that generates living radicals by light. Examples of the polymerization initiator include a benzoin compound, a benzophenone compound, an alkylphenone compound, a fluorenylphosphine oxide compound, and Compounds, iodonium salts, phosphonium salts, and the like.

As the sensitizer, a photosensitizer is preferred. Examples of the photosensitizer include oxyallone compounds, anthracene compounds, and phenothiazines , Rubrene, etc.

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 copolymerized with a polymerizable liquid crystal compound. For example, in the case where the polymerizable liquid crystal compound has a (meth) acrylic fluorenyloxy group, examples of the polymerizable non-liquid crystal compound include (meth) acrylates. The (meth) acrylates may be monofunctional or polyfunctional. By using a polyfunctional (meth) acrylate, the strength of a polarizing film can be improved. When a polymerizable non-liquid crystal compound is used, the polarizing film is preferably 1 to 15% by mass, more preferably 2 to 10% by mass, and even more preferably 3 to 7% by mass. When 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 compounds capable of reacting with a functional group of a polymerizable liquid crystal compound and a polymerizable non-liquid crystal compound. Specific examples of the crosslinking agent include isocyanate compounds, melamine, epoxy resins, Oxazoline compounds, etc.

After the composition for a polarizing film is directly coated on a base film or an alignment layer, it can be dried, heated, and hardened as required, thereby providing a polarizing film.

As the coating method, conventional methods such as a gravure coating method, a die coating method, a bar coating method, and an applicator method; a printing method such as a flexographic method can be used.

The drying is performed by introducing the coated substrate film into a warm air dryer, an infrared dryer, or the like, preferably at 30 to 170 ° C, more preferably at 50 to 150 ° C, and even more preferably at 70 to 130 ° C. The drying time is preferably 0.5 to 30 minutes, more preferably 1 to 20 minutes, and even more preferably 2 to 10 minutes.

The dichroic dye and the polymerizable liquid crystal compound in the polarizing film may be heated so as to be more firmly aligned. The heating temperature is preferably within a temperature range in which the polymerizable liquid crystal compound forms a liquid crystal phase.

Since the composition for a polarizing film contains a polymerizable liquid crystal compound, it is preferably cured. Examples of the curing method include heating and light irradiation, and light irradiation is preferred. By curing, the dichroic dye can be fixed in a state where it is oriented. The hardening is preferably performed in a state where the polymerizable liquid crystal compound is formed into a liquid crystal phase, and the temperature of the liquid crystal phase may be irradiated with light to harden it.

Examples of the rays of light include visible light, ultraviolet light, and laser light. From the viewpoint of easy handling, ultraviolet light is preferred.

The irradiation intensity varies depending on the type or amount of the polymerization initiator or resin (monomer), for example, it is preferably 100 to 10,000 mJ / cm ² , more preferably 200 to 5000 mJ / cm ² at a 365 nm standard.

In a polarizing film, a composition for a polarizing film is coated on an alignment layer provided according to requirements, and the dye is aligned along the alignment direction of the alignment layer. As a result, the polarization transmission axis has a predetermined direction. When the composition for a polarizing film is coated directly on a substrate without providing an alignment layer, the composition for a polarizing film can be hardened by irradiating polarized light, thereby orienting the polarizing film. Furthermore, it is preferable to perform a subsequent heat treatment, so that the dichroic dye can be firmly aligned along the alignment direction of the polymer liquid crystal.

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

In the case of laminating a polarizing film containing a polymerizable liquid crystal compound and a dichroic dye and a substrate film, not only a method of directly placing a polarizing film on the substrate film for lamination, but also setting polarizing light on other release films according to the above method The method of transferring the film to a substrate film is also preferred. Examples of the release film include a release support substrate used in the above-mentioned release support substrate laminated polarizer laminated with the release support substrate as a preferred example. As a particularly good release film, Examples include polyester films and polypropylene films. It is also possible to adjust the peeling force by performing a corona treatment on the release film, or by providing a release coating layer, an easy-adhesion coating layer, and the like on the release film.

The method for transferring the polarizing film to the substrate film is the same as the method described in the above-mentioned release-supporting substrate laminated polarizer laminated with the release-supporting substrate.

    (Orientation layer)    

As described above, the polarizer used in the present invention may be only a polarizing film, or a structure in which a polarizing film and an alignment layer are combined.

The orientation layer is used to control the orientation direction of the polarizing film. By providing the orientation layer, a polarizer having a higher degree of polarization can be provided.

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 imparting an alignment state to an alignment layer include a rubbing treatment applied to a surface, obliqui vapor deposition of an inorganic compound, and formation of a layer having microgrooves. Furthermore, it is preferable that the molecules have an orientation function by irradiating polarized light to orient the molecules to serve as a light alignment layer.

Hereinafter, two examples of the rubbing alignment layer and the light alignment layer will be described.

    [Friction treatment orientation layer]    

As the polymer material used in the alignment layer formed by the rubbing treatment, polyvinyl alcohol and its derivatives, polyimide and its derivatives, acrylic resins, and polysiloxane derivatives can be used.

First, a coating solution for a rubbing alignment layer containing the polymer material is applied on a substrate film, and then heated and dried to obtain an alignment layer before rubbing treatment. The coating liquid for an alignment layer may have a crosslinking agent. Examples of the crosslinking agent include a plurality of isocyanate groups, epoxy groups, Compounds such as oxazoline, vinyl, acrylic, carbodiimide, and alkoxysilyl; amine resins such as melamine compounds; phenol resins and the like.

Any solvent can be used as the solvent of the coating solution for the rubbing treatment alignment layer as long as it can dissolve the polymer material. Specific examples of the solvent include water; alcohol-based solvents such as methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, and cyrus; ester systems such as ethyl acetate, butyl acetate, and γ-butyrolactone Solvents; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, and 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 liquid for the rubbing treatment alignment layer can be appropriately adjusted according to the type of polymer and the thickness of the alignment layer to be manufactured, and is expressed in terms of solid content concentration, preferably 0.2 to 20% by mass, and more preferably 0.3 to A range of 10% by mass.

As a coating method, a conventional method such as a gravure coating method, a die coating method, a bar coating method, an applicator method, or a printing method such as a flexographic method can be used.

Although the heating and drying temperature is also related to the substrate film, 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 even more preferably in the range of 70 to 130 ° C. . If the drying temperature is too low, it may lead to a longer drying time and poor productivity. If the drying temperature is too high, it will affect the orientation of the substrate film, resulting in a decrease in hysteresis, or a large thermal shrinkage of the substrate film, and thus fail to achieve the optical function according to the design, resulting in problems such as poor planarity. The heating and 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-oriented layer is preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm, and even more preferably 0.1 to 1 μm.

The rubbing treatment is generally carried out by rubbing the surface of the polymer layer with paper or cloth in a certain direction. In general, a rubbing roller using a fabric such as nylon, polyester, or acrylic is used to rub the surface of the alignment film.

In order to provide a polarizing film having a penetration axis in a predetermined direction with respect to the long-side direction of the long substrate film, the rubbing direction of the alignment layer must also be an angle that matches with it. The angle can be adjusted by adjusting the angle between the friction roller and the substrate film, adjusting the conveying speed of the substrate film, and the number of rotations of the roller.

In addition, the base film may be directly subjected to a rubbing treatment so that the surface of the base film has a function of an alignment layer. This case is also included in the technical scope of the present invention.

    [Light directional layer]    

A photo-alignment layer refers to an alignment film in which a coating liquid containing a polymer or monomer having a photoreactive group and a solvent is coated on a substrate film, and then irradiated with polarized light, preferably polarized ultraviolet light, to thereby give an orientation restricting force. . The photoreactive group refers to a group that generates liquid crystal alignment energy by irradiating light. Specifically, it is a light reaction that generates the orientation energy of liquid crystal by irradiating light, such as inducing molecular orientation or causing isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction. Among these photoreactive groups, from the standpoint of excellent orientation and maintaining the state of the smectic liquid crystal of the polarizing film, those that cause a dimerization reaction or a photocrosslinking reaction are preferred. As the photoreactive group capable of generating the above reaction, an unsaturated bond is preferred, and a double bond is particularly preferred. Particularly preferred is a group selected from the group consisting of C = C bond, C = N bond, N = N bond, and C = O. A group of at least one of the group of bonds.

Examples of the photoreactive group having a C = C bond include a vinyl group, a polyalkenyl group, a distyryl group, an oxazolyl group, a stilbazolium group, a chalcone group, and a cinnamyl 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 fluorene. Examples of the photoreactive group having an N = N bond include an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a diazo group, and a methyl group. (formazan) group, azoxybenzene, etc. as the basic structure. 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 substituents 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 which can cause photodimerization reaction is preferred, and the cinnamyl and chalcone groups have a small amount of polarized light irradiation required for light orientation and are easy to obtain thermal stability or time. A light directing layer having excellent stability is preferred. To further explain, as the polymer having a photoreactive group, it is particularly preferable that the end portion of the side chain of the polymer has a cinnamic acid group having a cinnamic acid structure. Examples of the structure of the main chain include polyimide, polyimide, (meth) acrylic acid, and polyester.

Specific alignment layers include, for example, Japanese Patent Application Laid-Open No. 2006-285197, Japanese Patent Application No. 2007-76839, Japanese Patent Application No. 2007-138138, Japanese Patent Application No. 2007-94071, and Japanese Patent Application No. 2007 -121721, Japanese Patent Laid-Open No. 2007-140465, Japanese Patent Laid-Open No. 2007-156439, Japanese Patent Laid-Open No. 2007-133184, Japanese Patent Laid-Open No. 2009-109831, Japanese Patent Laid-Open No. 2002-229039 JP 2002-265541, JP 2002-317013, JP 2003-520878, JP 2004-529220, JP 2013-33248, and JP 2015-7702 The alignment layer described in the gazette, Japanese Patent Laid-Open No. 2015-129210, and the like.

As a solvent of the coating liquid for forming a photo-alignment layer, any polymer and monomer having a photo-reactive group can be used without limitation, as long as they are soluble. Specific examples of the solvent include those listed in the rubbing alignment layer. In the coating liquid for forming a photo-alignment layer, a photo-polymerization initiator, a polymerization inhibitor, various stabilizers, and the like may be added as required. In addition, a polymer having a photoreactive group and a polymer other than a monomer may be added to the coating liquid for forming a photo-alignment layer, and a monomer having no photoreactive group that can be copolymerized with the monomer having the photoreactive group may be added.体 等。 Body and so on.

Examples of the concentration, coating method, and drying conditions of the coating liquid for forming the photo-alignment layer include those listed in the rubbing-treatment alignment layer. The thickness of the light alignment layer is the same as the preferred thickness of the rubbing alignment layer.

With respect to the light alignment layer obtained before the orientation, polarized light of a predetermined direction is irradiated with respect to the long-side direction of the base film, thereby obtaining that the direction of the orientation limiting force is a predetermined direction relative to the long-side direction of the long base film Light directional layer.

The polarized light may be directly irradiated to the light alignment layer before the alignment, or it may be irradiated through the base film.

The wavelength of polarized light is preferably in a wavelength region where the photoreactive group of the polymer or monomer having the photoreactive group can absorb light energy. Specifically, ultraviolet rays having a wavelength in the range of 250 to 400 nm are preferred.

Examples of the polarized light source include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, KrF, ArF, and other ultraviolet lasers. Preferred are high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps.

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

By adjusting the angle of the polarized light, the direction of the directional limiting force of the light aligning layer can be arbitrarily adjusted.

The irradiation intensity varies depending on the type or amount of the polymerization initiator or resin (monomer). For example, it is preferably 10 to 10,000 mJ / cm ² and more preferably 20 to 5000 mJ / cm ² at a 365 nm standard.

    (Angle of the polarization axis of the polarizer and the slow axis of the substrate film)    

The angle of the polarization axis of the polarizer and the slow axis of the substrate film is not particularly limited. In order to prevent black screen or coloring when viewing images with polarized sunglasses, a range of 30 to 60 degrees is preferred, and a range of 35 to 55 degrees is more preferred. In order to reduce the slight rainbow spots when obliquely observing from a small angle, it is preferable to make it 10 degrees or less, and even more preferable to make it 7 degrees or less, or 80 to 100 degrees. It is better to make it 83 ~ 97 degrees. These angles can be adjusted by the bonding angle of the base film and the polarizer, the direction in which the base film extends obliquely, or the angle controlled by the orientation of the alignment layer.

    3. Phase difference layer    

In the circular polarizing plate used in the present invention, a retardation layer is present on the side opposite to the base film surface of the polarizer. That is, in this circularly polarizing plate, a retardation layer is provided on the electroluminescence (EL) unit side of the polarizer. The state where there is no self-supporting film between the polarizer and the retardation layer or only one sheet (here, the retardation layer itself is included between the polarizer and the retardation layer) is a state of the EL display device of the present invention. One of the features. Here, the self-supporting film refers to a form that is independent of a process and exists as a film.

In addition, the "phase difference layer" referred to here refers to a person who functions as a circularly polarizing plate, and specifically refers to a 1/4 wavelength layer, a 1/2 wavelength layer, a C plate layer, and the like.

There is no self-supporting film between the polarizer and the retardation layer, which means that the polarizer is directly laminated as a retardation layer of a non-self-supporting film. "Direct" as used herein means that there are no other layers between the polarizer and the retardation layer and between the retardation layers, or even if they exist, they are only adhesion layers or adhesive layers.

There is one self-supporting film between the polarizer and the retardation layer, which means that there is only one self-supporting film between the polarizer protective film and all the retardation layers.

The retardation layer includes a 1/2 wavelength layer and a 1/4 wavelength layer.

The 1 / 2-wavelength layer can be obtained by attaching a separately prepared device on an alignment film (self-supporting film) such as polycarbonate or cycloolefin or a triethylfluorene-based (TAC) film. There is a retardation film (self-supporting film) of a coating type 1/2 wavelength layer described later. However, from the viewpoint of ensuring thinness and flexibility, it is preferable to provide a coating type 1/2 wavelength layer directly on the polarizer.

The coating type 1 / 2-wavelength layer is a 1 / 2-wavelength layer formed by coating the 1 / 2-wavelength layer body, and does not become an independent state as a monomer. Examples of the method for providing a 1 / 2-wavelength layer include a method of applying a retardation compound to a polarizer, and a method of providing a 1 / 2-wavelength layer on a release substrate and transferring the same to a polarizer. Method, etc. As the 1/2 wavelength layer, a layer containing a liquid crystal compound is preferred. Examples of the liquid crystal compound include a rod-like liquid crystal compound, a polymer-like liquid crystal compound, and a liquid crystal compound having a reactive functional group. As a method of applying a retardation compound to a polarizer, it is preferable to perform a rubbing treatment on the polarizer, or to apply a liquid crystal compound after providing an alignment layer as described above on the polarizer to have an alignment control force.

In addition, in the method of providing a coating-type 1/2 wavelength layer on a release substrate and transferring it to a polarizer, it is preferable to perform a rubbing treatment on the release substrate, or a release substrate After the alignment layer as described above is provided so as to have an alignment control force, a liquid crystal compound (1/2 wavelength layer) is applied.

In addition, as a method for transferring, a method of applying a birefringent resin to a substrate having a release property, and further extending the substrate one by one to form a 1/2 wavelength layer is also preferable.

The transfer-type 1/2 wavelength layer thus obtained was bonded to a polarizer using an adhesive or an adhesive, and then the release substrate was peeled. In order to reduce the thickness, bonding is preferably performed using an adhesive, particularly an ultraviolet curing adhesive. It is also preferable to use an adhesive from the viewpoint that a special device is not required in the manufacturing process.

From the viewpoint that the polarizer is not easily affected by the coating solvent of the 1 / 2-wavelength layer, a method of separately providing a coating-type 1 / 2-wavelength layer on a release substrate and transferring it to the polarizer is preferred.

The front-side hysteresis of the 1/2 wavelength layer is preferably 200 to 360 nm, and more preferably 240 to 300 nm.

For these methods and phase difference layers, for example, refer to Japanese Patent Application Laid-Open No. 2008-149577, Japanese Patent Application Laid-Open No. 2002-303722, WO2006 / 100830, Japanese Patent Laid-Open No. 2015-64418, and the like.

The preferred material, morphology, manufacturing method, and lamination method of the quarter-wavelength layer are the same as those of the above-mentioned half-wavelength layer. Preferably, a 1/4 wavelength layer is provided on the 1/2 wavelength layer by coating or transfer.

The front-side retardation of the 1/4 wavelength layer is preferably 100 to 180 nm, and more preferably 120 to 150 nm.

The angle (θ) of the orientation axis (slow axis) of the 1/2 wavelength layer and the transmission axis of the polarizer is preferably 5-20 degrees, and more preferably 7-17 degrees. The angle between the orientation axis (slow axis) of the 1/2 wavelength layer and the orientation axis (slow axis) of the 1/4 wavelength layer is preferably in the range of 2θ + 45 degrees ± 10 degrees, and more preferably in the range of 2θ + 45 degrees ± The range of 5 degrees is even better in the range of 2θ + 45 degrees ± 3 degrees.

These angles can be adjusted by the angle of lamination, the extension direction of the alignment film, and the like when the alignment film is bonded.

In the case of a coating type 1/4 wavelength layer and a 1/2 wavelength layer, the angle of rubbing, the angle of irradiation of polarized ultraviolet rays, and the like can be controlled.

In the method of setting a coating-type 1/4 wavelength layer on a substrate and transferring it to a polarizer, in the case of roll-to-roll bonding, it is preferably controlled by a rubbing angle or an irradiation angle of polarized ultraviolet rays so that It becomes an established angle.

In the case where an orientation film is used and the case where a birefringent resin is applied to a base film and then stretched together with the base material, it is preferable to extend in an oblique upward direction to make the roll-to-roll bonding a predetermined angle.

In addition, in order to reduce the change in coloring when viewed obliquely, it is also preferable to provide a C plate layer on the 1/4 wavelength layer. The C plate layer can be used with a positive or negative C plate layer in accordance with the characteristics of the 1/4 wavelength layer or the 1/2 wavelength layer. The C plate layer is preferably a liquid crystal compound layer. The C plate layer can be directly coated on the 1/4 wavelength layer as a coating liquid for the C plate layer, or the C plate layer prepared separately can also be transferred.

As such a lamination method, various methods can be adopted. For example, the following methods are mentioned.

‧A method of setting a 1/2 wavelength layer on a polarizer by transferring, and then setting a 1/4 wavelength layer on it by transferring.

‧A method of sequentially setting a 1/4 wavelength layer and a 1/2 wavelength layer on a release film, and then transferring them to 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 of preparing a film-shaped 1 / 2-wavelength layer, and applying a 1 / 4-wavelength layer on it by coating or transferring it, and then bonding it to a polarizer.

In the case where the C plate layer is laminated, various methods can be adopted. For example, a method in which a C plate layer is provided on a 1/4 wavelength layer provided on a polarizer by coating or transfer, a method in which a C plate layer is provided in advance on a transferred or bonded 1/4 wavelength layer, etc. .

In the present invention, when the C plate layer exists between the polarizer and the 1/4 wavelength layer (including the 1/4 wavelength layer), it is preferable that all layers (including the C plate layer) from the polarizer to the C plate layer are included. Is a coating layer. This is because there is no self-supporting film on the side opposite to the base film of the polarizer. Specifically, only any combination of an adhesive layer, an adhesive layer, a protective coating layer, an alignment layer, and a coating type retardation layer is present on the side opposite to the base film of the polarizer. With such a configuration, it is possible to reduce the thickness of the circular polarizing plate and to ensure flexibility.

As specific examples of being laminated between the polarizer and the 1/4 wavelength layer, a polarizer / 1/2 wavelength layer / adhesive layer / 1/4 wavelength layer, a polarizer / adhesive layer / 1 / 2 wavelength layer / adhesive layer / 1/4 wavelength layer, polarizer / protective coating / 1/2 wavelength layer / adhesive layer / 1/4 wavelength layer, polarizer / protective coating / adhesive layer / 1 / 2 wavelength layer / adhesive layer / 1/4 wavelength layer.

In addition, among the above, the adhesive layer may be an adhesive layer. The 1/4 wavelength layer and the 1/2 wavelength layer may include an alignment layer on either side.

The adhesive layer is not limited, and a rubber-based, acrylic-based, urethane-based, olefin-based, or silicone-based adhesive can be used. Among these, an acrylic adhesive is preferable. The adhesive can be applied to an object, such as one side of a polarizer in a polarizing plate. It is preferable to provide an adhesive layer on one side of a polarizer after peeling off the single-sided release film of a substrate-free optical transparent adhesive (release film / adhesive layer / release film) and then bonding it to one side of a polarizer. Methods. As the adhesive, a UV-curable, urethane-based, and epoxy-based adhesive is preferably used.

The adhesive layer or the adhesive layer is used for bonding a polarizer, a protective coating, a coating retardation layer, or an image display unit.

In the above, the retardation layer (1/4 wavelength layer and 1/2 wavelength layer) has been exemplified as an example in which the retardation layer (the 1/4 wavelength layer and the 1/2 wavelength layer) is attached to an object after being provided on a laminated body of a base film and a polarizer, but also A retardation layer (a 1/4 wavelength layer and a 1/2 wavelength layer) may be provided on the object in advance, and then a laminated body of the substrate film and the polarizer may be bonded thereto. The same is true for the C-plate layer.

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

Furthermore, a circularly polarizing reflective layer containing a liquid crystal compound may be provided on the retardation layer of the circularly polarizing plate (the surface on the side opposite to the polarizer). The circularly polarized light reflecting layer is preferably a cholesteric liquid crystal layer. The cholesteric liquid crystal layer may be one layer, but the cholesteric liquid crystal layer has wavelength selectivity in its reflection characteristics. In order to exhibit uniform reflection characteristics in a wide range of visible light, it is preferable to provide a plurality of cholesteric liquid crystal layers. The cholesteric liquid crystal layer is more preferably two or more layers, and even more preferably three or more layers. The cholesteric liquid crystal layer is preferably 7 layers or less, even more preferably 6 layers or less, and particularly preferably 5 layers or less.

The circularly polarizing reflective layer is preferably provided by coating or transferring a coating material for a circularly polarizing reflective layer containing a liquid crystal compound.

Examples of the liquid crystal compound used in the circularly polarizing reflective layer include liquid crystal compounds used in the aforementioned polarizing film or retardation layer.

Furthermore, in order to orient the circularly polarized light reflection layer to the cholesteric liquid crystal, it is preferable that the coating material for the circularly polarized light reflection layer contains a palm additive. By containing a palmitic additive, a helical structure of a cholesteric liquid crystal phase can be induced, and a cholesteric liquid crystal phase can be easily obtained.

The palm additive is not particularly limited, and conventional palm additives can be used. Examples of palm additives include liquid crystal device manuals, Chapter 3, items 4-3, palm agents for TN (Twisted Nematic), STN (Super-twisted nematic display), 199 pages, Japan Society for the Promotion of Science 142th Committee Eds., Compounds described in 1989, isosorbide, mannitol (Isomannide) derivatives, and the like. The palm additive preferably has a polymerizable group. The blending amount of the palm additive is preferably 1 to 10 parts by mass based on 100 parts by mass of the liquid crystal compound.

In the case where the circularly polarized light reflection layer is provided on the retardation layer by coating, it may be directly coated on the retardation layer, or an orientation layer may be provided and then coated thereon. When a circularly polarized reflective layer is provided by transfer, a coating for a circularly polarized reflective layer may be directly coated on a release substrate, or a circularly polarized reflective layer may be coated on the release substrate after an orientation layer is provided thereon. With paint. It is also possible to sequentially arrange a circularly polarized reflective layer and a retardation layer on a release substrate, and then transfer them to a polarizer. It is also possible to sequentially arrange a circularly polarized reflective layer and a part of the retardation layer on the release substrate, and further provide another part of the retardation layer on the polarizer, and then transfer it to the retardation layer. The alignment layer is preferably one described above.

The circularly polarized reflective layer can be referred to, for example, Japanese Patent Laid-Open No. 1-133003, Japanese Patent No. 3416302, Japanese Patent No. 3363565, Japanese Patent Laid-Open No. 8-271731, International Publication No. 2016/194497, and Japanese Patent Laid-Open Contents described in the 2018-10086 and the like.

The thickness of the circularly polarized reflective layer is preferably 2.0 to 150 μm, and more preferably 5.0 to 100 μm. In addition, when the circularly polarized light reflection layer is a plurality of layers, the total thickness is preferably within the above range.

By combining a circularly polarizing reflective layer and a circularly polarizing plate, it is possible to provide a circularly polarizing plate for preventing reflection in an EL display device, thereby reducing a decrease in brightness. Furthermore, the polarizer, the retardation layer, and the circularly polarized reflective layer are provided by coating or transfer, so that the polarizer and the circularly polarized reflective layer (including the polarizer itself and the circularly polarized reflective layer) are not self-supporting. With the structure of the film, the circularly polarizing plate can be thinned, and the thickness of the EL display device can be easily reduced. Moreover, such a structure is most suitable as a flexible EL display device such as a foldable, rollable, and the like.

    [B.EL unit]    

The EL display device of the present invention includes the aforementioned circularly polarizing plate closer to the viewing side than the EL unit. The EL unit is not limited, and a conventional one can be used. Among them, an organic EL unit is preferred from the viewpoint of thinness. Preferably, the EL unit and the circularly polarizing plate are bonded together with an adhesive.

Since the EL display device of the present invention uses a base film having a specific in-plane retardation, the number of self-supporting films existing between the polarizer and the retardation layer is one or less, and a wavelength of 1/2 is used. As the retardation plate, the circular polarizing plate of the layer and the 1/4 wavelength layer is excellent in visibility (suppression of iridescence), can be made thin, and it is unlikely to cause problems in the manufacturing process. It is particularly suitable for large EL display devices of type 40 (the diagonal length of the display section is 40 inches) or more, and furthermore type 50 (the diagonal length of the display section is 50 inches) or more.

Moreover, in the case of a flexible EL display device, even when repeatedly folded or placed in a high-temperature state, the laminated members are not easily peeled from each other, and creases are hardly generated.

As a flexible EL display device, an EL display device (foldable EL display device) that can be folded into a V shape, a Z shape, a W shape, a double-open shape or the like when being carried, or a roll shape Either an EL display device (roll-type EL display device).

When the folding type EL display device has a display portion on the inner side of the fold, the bending radius of the circular polarizing plate becomes smaller in the folded state. In the case of such an EL display device, by arranging the main orientation direction of the base film in a direction perpendicular to the folding direction (the direction of the folding operation), it is possible to effectively reduce the fold marks caused by repeated folding operations. In addition, in the vertical direction, the angle between the main orientation direction of the substrate film and the folding direction is preferably 75 to 105 degrees, more preferably 80 to 100 degrees, and even more preferably 83 to 97 degrees.

As a reason for reducing the fold marks, it is considered that although the base film is stretched by repeated folding operations, the base film is easily stretched because the stretching direction is perpendicular to the main orientation direction of the molecules. The flexible image display device of the present invention can be preferably used for a folding image display device with a bending radius of 5 mm or less, more preferably 4 mm or less, and particularly preferably 3 mm.

In the case of a folding type EL display device, a display portion is provided on the outer surface side of the fold of the device, or the bending radius does not become small even on the inner surface, or in the case of a roll-type image display device, The main orientation is not particularly limited and can be used. However, in such a case, it is also preferable to make the main orientation direction of the base film parallel to the folding direction. By making them parallel, there is a tendency that the flatness of the entire image display device is improved during the development. 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 does not peel off even when repeatedly bent or left in a high-temperature state, is less prone to creases, and has excellent visibility. When a polyester film is used as the base film of the circular polarizing plate, an EL display device having a circular polarizing plate having excellent moisture permeability resistance, dimensional stability, mechanical strength, and chemical stability can be provided.

Examples

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. Variations may be appropriately added and implemented within a range consistent with the gist of the present invention, and these are included in the technical scope of the present invention.

The physical property evaluation method in an Example is as follows.

    (1) Hysteresis (Re)    

Hysteresis is a parameter defined by the product of the biaxial orthogonal refractive index anisotropy (△ Nxy = | nx-ny |) and film thickness d (nm) (△ Nxy × d). Optical isotropic and anisotropic scale. The biaxial refractive index anisotropy (ΔNxy) is determined by the following method. A molecular orientation instrument (manufactured by Oji Scientific Instruments, MOA-6004 molecular orientation instrument) was used to determine the orientation axis direction of the film. The orientation axis direction was taken as the long side, and a 4 cm × 2 cm rectangle was cut out for measurement. sample. For this sample, the refractive index (nx, ny) of the orthogonal biaxial and refractive index (nz) in the thickness direction were measured using an Abbe refractometer (NAR-4T, manufactured by ATAGO, measuring wavelength: 589 nm), and the two The absolute value (| nx-ny |) of the difference between the refractive indexes of the axes is taken as the anisotropy (ΔNxy) of the refractive index. The film thickness d (nm) was measured using an electronic micrometer (manufactured by Feinpruf, Millitron 1245D), and the unit was converted to nm. The hysteresis (Re) is obtained from the product of the anisotropy (ΔNxy) of the refractive index and the film thickness d (nm) (ΔNxy × d).

    (2) Nz coefficient    

Let the value obtained by | ny-nz | / | ny-nx | be the Nz coefficient. Among them, the values of ny and nx are selected as ny> nx.

    (3) Plane orientation (△ P)    

The value obtained by (nx + ny) / 2-nz was used as the degree of plane orientation (ΔP).

    (4) Thickness Hysteresis (Rth)    

The hysteresis in the thickness direction refers to the average of the hysteresis obtained by multiplying the two birefringences △ Nxz (= | nx-nz |) and △ Nyz (= | ny-nz |) by the film thickness d when viewed from the film thickness section. Parameters. Using the same method as measuring hysteresis, find nx, ny, nz, and film thickness d (nm), and calculate the average value of (△ Nxz × d) and (△ Nyz × d) to obtain the thickness direction hysteresis (Rth) .

    (5) Transmittance at 380nm    

Using a spectrophotometer (U-3500, manufactured by Hitachi, Ltd.), the air transmittance of each film in a wavelength region of 300 to 500 nm was measured using an air layer as a standard, and the light transmittance at a wavelength of 380 nm was determined.

Various characteristics of the above-mentioned base film are obtained by sampling three points (three points at the center and both ends) in the width direction and taking an average value.

    (6) The angle of the film orientation main axis and the long side direction, or the angle of the film orientation main axis and the direction orthogonal to the long side direction    

The orientation major axis direction of the film was determined using a molecular orientation instrument (manufactured by Oji Scientific Instruments, MOA-6004 molecular orientation instrument), and it is an angle at a direction perpendicular to the long side direction or a direction orthogonal to the long side direction. Means.

    (7) Thickness of base film and circular polarizer    

The thickness of the substrate film and the circular polarizing plate were measured with a commercially available digital thickness meter.

    (8) Thickness of each layer formed by coating    

The thickness of each layer formed by coating is embedded with a PET film (PET which is easy to be subsequently processed according to requirements) coated with epoxy resin under the same coating conditions, embedded, cut out, and observed with a microscope. The microscope uses an optical microscope, a transmission electron microscope, or a scanning electron microscope depending on the thickness.

    (9) Operability    

The produced circular polarizing plate was cut to a size equivalent to A5, and wound on a paper tube having an outer diameter of 6 inches with a length direction as a rolling direction, and wound with a biaxially stretched PET film having a thickness of 50 μm. At the time point when the PET film was wound for 3 m, the circularly polarizing plate sample was inserted, and then the 7 m PET film was wound. In addition, those who wound only the base film were prepared as a control group. These were stored at 40 ° C for 3 days, and then unwound after returning to room temperature, with the curved convex portions facing upward, and placed on a glass plate, and the state of bending after 30 minutes was observed. In addition, it was pressed from above to test whether it was easy to level it. The evaluation criteria are as follows.

(Double-circle): It is substantially the same as a control group, and there is almost no curvature.

：: The degree of bending is slightly larger than that of the control group, but it is easy to make it flat.

△: The degree of bending is larger than that of the control group, but it can be made flat.

×: The degree of bending is much larger than that of the control group, and it is difficult to make it flat.

    (10) Corresponding polarized sunglasses    

From a commercially available organic EL display (organic EL TV C6P 55 inch manufactured by LG), a circular polarizer (a circular polarizer disposed closer to the viewing side than an organic EL element) was removed instead of a PET film For the arrangement on the viewing side, the circular polarizing plate obtained below is arranged in an organic EL display. The absorption axis of the polarizer is arranged in the same manner as the absorption axis of the polarizer of the original circular polarizer.

Wear polarized sunglasses to observe the display. The evaluation criteria are as follows.

○: No rainbow spots were observed, and images were visible (the slow axis direction of the substrate film and the absorption axis direction of the polarizer was about 45 degrees)

×: There is an angle where the image is completely black and cannot be viewed (the slow axis direction of the base film is orthogonal to or parallel to the absorption axis direction of the polarizer)

    (11) Anti-reflection effect    

The anti-reflection effect of the EL display device used in the evaluation of the above (10) was visually confirmed.

(Circle): It is confirmed that it has almost the same antireflection effect as the original circularly polarizing plate.

×: No antireflection effect was found.

    (12) r = 3 bending resistance    

A sample of a circularly polarizing plate having a size of 50 mm × 100 mm was prepared, and a bending radius of 3 mm was set at a speed of 1 mm / sec using a no-load U-shaped telescoping tester (DLDMLH-FS, manufactured by YUASA SYSTEM). Ten thousand times. At this time, the sample is fixed at a position of 10 mm at both ends of the long side, and the bent portion is 50 mm × 80 mm, the inside of the bend is the base film side, and the slow axis of the base film is orthogonal to the bending direction . After the bending process is finished, the curved inside of the sample is placed downward and placed on a flat surface, and the inspection is performed visually. The evaluation criteria are as follows.

：: Deformation of the sample cannot be confirmed.

○: Although the sample is deformed, the maximum height of floating when the sample is placed horizontally is less than 5 mm.

×: When the sample has creases or is placed horizontally, the maximum height of floating is 5 mm or more.

    (13) r = 5 bending resistance    

The bending radius was set to 5 mm, the outer side of the bend was the base film side, and the slow axis of the base film was parallel to the bending direction. The test was performed in the same manner as in the r = 3 bend resistance test.

    (14) Heat resistance    

A sample having a size of 50 mm × 100 mm was bent 180 degrees in the direction of the long side so that the base film surface was inside and the bending radius was 3 mm. The sample was fixed with a tool and left at a temperature of 60 ° C and RH 65% for 3 hours. Then, the fixture was removed at room temperature, and the state after 1 hour was observed. The slow axis of the base film was orthogonal to the bending direction. The evaluation criteria are as follows.

◎: almost restored to a flat surface

○: Slightly bent (less than 20 degrees)

×: Bent state (20 degrees or more)

    <Production of easy-adhesive layer components>         (Polymerization of polyester resin)    

In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux cooler, 194.2 parts by mass of dimethyl terephthalate, 184.5 parts by mass of dimethyl isophthalate, and 14.8 parts by mass of m-benzene Sodium dimethyl dicarboxylate-5-sulfonate, 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 at a temperature from 160 ° C to 220 ° C It took 4 hours to carry out the transesterification reaction. Next, the temperature of the mixture was raised to 255 ° C, and the reaction system was gradually depressurized, and then the reaction was performed under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolymerized polyester resin. The obtained copolymerized polyester resin was light yellow and transparent. The reduction viscosity of the copolymerized polyester resin was measured and found to be 0.70 dl / g. In addition, the reduction viscosity is based on 0.1 g of resin, using a mixed solvent of 25 mL of phenol (60 mass%) and 1,1,2,2-tetrachloroethane (40 mass%) as a solvent at 30 ° C The measured value. The glass transition temperature measured by DSC was 40 ° C.

    (Preparation of polyester water 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 placed, and the resin was dissolved by stirring while heating at 110 ° C. After the resin was completely dissolved, 55 parts by mass of water was slowly added while stirring the polyester solution. After the addition was completed, the mixture was cooled to room temperature while stirring the mixed solution to obtain a milky white polyester aqueous dispersion having a solid content of 30% by mass.

    (Preparation of polyvinyl alcohol aqueous solution)    

In a container equipped with a blender and a thermometer, 90 parts by mass of water was put, and 10 parts by mass of a polyvinyl alcohol resin (Kuraray, polymerization degree: 500 and saponification degree: 74%) were slowly added while stirring. After the addition was completed, the mixture was heated to 95 ° C while stirring the mixed solution to dissolve the resin. After the resin was dissolved, the mixed solution was cooled to room temperature while stirring, to obtain a 10% by mass polyvinyl alcohol aqueous solution having a solid content.

    (Polymerization of the blocked polyisocyanate crosslinking agent used in the easy-adhesive layer P1)    

A flask equipped with a stirrer, a thermometer, and a reflux cooling tube was charged with 100 parts by mass of a polyisocyanate compound (manufactured by Asahi Chemicals, DURANATE TPA) having an isopolycyanate structure using hexamethylene diisocyanate as a raw material. 55 parts by mass of propylene glycol monomethyl ether acetate and 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750), and kept at 70 ° C. for 4 hours in a nitrogen environment. Thereafter, the temperature of the reaction solution was lowered to 50 ° C., and 47 parts by mass of methyl ethyl ketoxime was dropped. The infrared spectrum of the reaction liquid was measured, and it was confirmed that the absorption of the isocyanate group disappeared, and a blocked polyisocyanate aqueous dispersion liquid having a solid content of 75% by mass was obtained.

    (Preparation of coating solution for easy-adhesive layer P1)    

The following raw materials were mixed to prepare a coating liquid.

    (Easily polymerizes urethane resin used in layer P2)    

A urethane resin containing an aliphatic polycarbonate polyol as a constituent is prepared in the following procedure. In a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen introduction tube, a silica gel drying tube, and a thermometer, 43.75 parts by mass of 4,4-diphenylmethane diisocyanate and 12.85 parts by mass were placed. Parts of dimethylolbutyric acid, 153.41 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent, in a nitrogen atmosphere The mixture was stirred at 75 ° C for 3 hours, and it was confirmed that the reaction solution reached a predetermined amine equivalent. Next, the temperature of the reaction solution was lowered to 40 ° C, and then 8.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, in a reaction vessel equipped with a homogeneous disperser capable of high-speed stirring, 450 g of water was added and the temperature was adjusted to 25 ° C. The water was stirred and mixed at a rotation speed of 2000 min ^-1 , and a polyurethane prepolymer solution was added. It's scattered. Then, a part of the acetone and water was removed from the mixed solution under reduced pressure, thereby preparing a water-soluble polyurethane resin having a solid content of 35%. The glass transition point temperature of the obtained polyurethane resin containing an aliphatic polycarbonate polyol as a constituent component was -30 ° C.

(Easy to use in layer P2 Polymerization of oxazoline crosslinking agent)

In a flask equipped with a thermometer, a nitrogen introduction tube, a reflux cooler, a dropping funnel, and a stirrer, a mixture of 58 parts by mass of ion-exchanged water and 58 parts by mass of isopropyl alcohol as an aqueous medium, and 4 parts by mass of polymerization initiation were charged. Agent (2,2'-azobis (2-fluorenylpropane) ‧ dichlorate). On the other hand, in a dropping funnel, put as 2-isopropenyl-2-, polymerizable unsaturated monomer of oxazoline group A mixture of 16 parts by mass of oxazoline, 32 parts by mass of methoxypolyethylene glycol acrylate (average addition mole number of ethylene glycol: 9 moles, manufactured by Shin Nakamura Chemical Co., Ltd.), and 32 parts by mass of methyl methacrylate In a nitrogen environment, the solution was dripped at 70 ° C for 1 hour. After the dropping was completed, the reaction solution was stirred for 9 hours and cooled to obtain a solid content concentration of 40% by mass. An oxazoline-based water-soluble resin.

    (Preparation of coating liquid for easy-adhesion layer P2)    

The following raw materials were mixed to prepare a coating liquid for forming a coating layer having excellent adhesion to the functional layer.

    <Production of polyester resin for base film>         (Production Example 1-Polyester X)    

The esterification reaction tank was heated, and when it reached 200 ° C, 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were added, and 0.017 parts by mass of antimony trioxide as a catalyst and 0.064 were added while stirring. Parts by mass of magnesium acetate tetrahydrate, and 0.16 parts by mass of triethylamine. Next, the temperature was increased by pressure, and the pressure esterification reaction was performed under the conditions of a gauge pressure of 0.34 MPa and 240 ° C. Then, the esterification reaction tank was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. It took another 15 minutes to raise the temperature to 260 ° C, and added 0.012 parts by mass of trimethyl phosphate. Next, after 15 minutes, dispersion treatment was performed using a high-pressure disperser. After 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction tank, and a polycondensation reaction was performed at 280 ° C under reduced pressure.

After the polycondensation reaction is completed, the filter is processed by a NASLON filter with a 95% division diameter of 5 μm, extruded from a nozzle into a strand shape, and cooled and hardened with cooling water that has been previously filtered (pore diameter: 1 μm or less). Cut into granules. The limiting viscosity (inherent viscosity) of the obtained polyethylene terephthalate resin (X) was 0.68 dL / g, and substantially no inactive particles and internally precipitated particles were contained (hereinafter, polyethylene terephthalate resin (X) is referred to as PET (X)).

    (Production Example 2-Polyester Y)    

The dried ultraviolet absorbent (2,2 '-(1,4-phenylene) bis (4H-3,1-benzo 4-ketone) 10 parts by mass and 90 parts by mass of PET (X) were mixed, and a kneading extruder was used to obtain a polyethylene terephthalate resin (Y) containing an ultraviolet absorber. (Hereinafter, the polyethylene terephthalate resin (Y) is simply referred to as PET (Y)).

    (Manufacture of base film)    

As a raw material for the intermediate layer of the base film, 90 parts by mass of PET (X) resin particles containing no particles and 10 parts by mass of PET (Y) resin particles containing ultraviolet absorbers were dried under reduced pressure at 135 ° C (1 Torr). 6 After an hour, it was supplied to the extruder 2 (for the intermediate layer II), and PET (X) was dried by a conventional method, and each was supplied to the extruder 1 (for the outer layer I and the outer layer III), and dissolved at 285 ° C. The two kinds of polymers were respectively filtered with a filter material of a stainless steel sintered body (95% of particles with a nominal filtering accuracy of 10% cut), and two kinds of three-layer converged blocks were laminated, extruded into a sheet form from a nozzle, and then electrostatically casted. , It is wound on a casting drum with a surface temperature of 30 ° C, and is cooled and solidified to produce an unstretched film. At this time, the discharge amount of each extruder was adjusted so that the thickness ratio of the I layer, the II layer, and the III layer was 10:80:10.

Next, a P1 coating liquid was coated on one side of the unstretched PET film so that the coating amount after drying was 0.12 g / m ² by a reverse roll method, and the P2 coating liquid was coated on the opposite side, and then introduced into a dryer. , And dried at 80 ° C for 20 seconds.

The unstretched film on which the coating layer was formed was introduced into a tenter stretcher, and while the end portion of the film was clamped by a jig, it was introduced into a hot air region at a temperature of 135 ° C and extended 3.8 times in the width direction. Next, while maintaining the extension in the width direction, it was treated at a temperature of 225 ° C for 30 seconds, and then cooled to 130 ° C. Then, both ends of the film were cut with a shearing knife, and the thickness was 0.5 kg / mm ² . The ears were removed by tension and wound, and a uniaxially oriented PET film (TD) with a film thickness of 70 μm was obtained. The limiting 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 main axis (slow axis) of the orientation of the film was measured for a total of 5 points at the two ends of the obtained film in the longitudinal direction, the central portion, and the middle portion located between the end portion and the central portion. The orientation main axis is a direction orthogonal to the long side direction, and the angle between the orientation main axis and the direction orthogonal to the long side direction is an average of 0 degrees at 5 points, and a maximum of 5 degrees among the 5 points.

Similarly, the obtained unstretched film was heated to 105 ° C. using a heated roller group and an infrared heater, and then extended 4 times in the traveling direction with a roller group having a peripheral speed difference. Next, a P1 coating liquid was applied to one side of the PET film extended in the longitudinal direction by a reverse roll method so that the coating amount after drying was 0.12 g / m ² , and a P2 coating liquid was applied to the opposite side. Introduce a tenter stretcher, hold the end of the film with a clamp, and dry at a temperature of 135 ° C while maintaining the width. After processing at 220 ° C for 30 seconds, cool to 130 ° C and wind to obtain a film. Uniaxially oriented PET film (MD) with a thickness of 70 μm. The characteristics of the obtained uniaxially oriented PET film (MD) are shown in Table 1.

The orientation major axis of the obtained film is the long side direction, and the angle between the orientation major axis and the long side direction is an average of 5 degrees at 5 points, and a maximum of 1 degree among the 5 points.

    (Lamination of hard coating)    

95 parts by mass of a urethane acrylate-based hard coat agent (manufactured by Arakawa Chemical Industries, BEAMSET (registered trademark) 577, solid content concentration 100%), and 5 parts by mass of a photopolymerization initiator (BASF Japan) System, Irgacure (registered trademark) 184, solid content concentration 100%) and 0.1 parts by mass of a leveling agent (by BYK Japan, BYK307, solid content concentration 100%) were mixed and diluted with a solvent of toluene / MEK = 1/1 , To prepare a coating solution with a concentration of 40%.

Using a wire rod, apply a hard coat coating solution on the easy-adhesive layer P2 surface of the base film so that the film thickness after drying is 5.0 μm. After drying at 80 ° C. for 1 minute, irradiate ultraviolet rays (integrated light quantity 200mJ / cm ² ).

    (Laminated Polarizers)    

As a method of installing a polarizer on a base film, the following four methods were performed.

(A) A method of providing a rubbing alignment layer on a substrate film, and then providing a polarizing film containing a liquid crystal compound and a dichroic dye thereon (polarizer lamination method A)

(B) A method of providing a light directing layer on a substrate film, and further providing a polarizing film including a liquid crystal compound and a dichroic dye thereon (polarizer lamination method B)

(C) A method in which a polarizing film containing PVA / iodine is provided on a thermoplastic substrate and then transferred to the substrate film (polarizing lens lamination method C)

(D) Method for producing a polarizing film containing PVA / iodine and bonding it to a base film (polarizer lamination method D)

The details of each method are as follows.

    [Polarizer Lamination Method A]         (Formation of Friction Orientation Layer)    

Using a bar coater, a coating material for a friction alignment layer having the following composition was applied to the easy-adhesive layer P1 side of the base film, and dried at 120 ° C. for 3 minutes to form a film having a thickness of 200 nm. Next, the surface of the obtained film was treated with a rubbing roller wound with a nylon wicking cloth to obtain a base film in which a rubbing alignment layer was laminated. The rubbing direction is 0 degrees, 45 degrees, or 90 degrees with respect to the longitudinal direction of the film.

Coating for friction alignment layer

    (Synthesis of polymerizable liquid crystal compound)    

With reference to the description in paragraph [0134] of Japanese Patent Publication No. 2007-510946 and Lub et al. Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), a compound (A) represented by the following formula (1) was synthesized. And a compound (B) represented by the following formula (2).

With reference to Example 1 of Japanese Patent Application Laid-Open No. 63-301850, a dye (c) represented by the following formula (3) was synthesized.

With reference to Example 2 of Japanese Patent Publication No. 5-49710, a dye (D) represented by the following formula (4) was synthesized.

With reference to the method for producing a compound of general formula (1) in Japanese Patent Publication No. 63-1357, a dye (penta) represented by the following formula (5) is synthesized.

    (Formation of polarizing film)    

Using a bar coater, 75 parts by mass of a compound (a), 25 parts by mass of a compound (b), 2.5 parts by mass of a dye (c), 2.5 parts by mass of a dye (butyl), and 2.5 parts by mass of a dye (penta) , 6 parts by mass of Irgacure (registered trademark) 369E (manufactured by BASF) and 250 parts by mass of o-xylene polarizing film coating material were coated on a substrate film laminated with a friction alignment layer, and dried at 110 ° C for 3 minutes to form Film with a thickness of 2 μm. Next, UV light was irradiated, and a polarizer was set on the base film.

    [Polarizer Lamination Method B]         (Synthesis of coating for photo-alignment layer)    

According to the description of Example 1, Example 2, and Example 3 of Japanese Patent Application Laid-Open No. 2013-33248, a 5% by mass solution of the polymer (hexane) represented by the following formula (6) in cyclopentanone was produced.

    (Formation of Light Alignment Layer)    

A coating material for a photo-alignment layer having the above composition was applied to one side of a base film using a bar coater, and dried at 80 ° C. for 1 minute to form a film having a thickness of 150 nm. Next, polarized UV light was irradiated to obtain a base film in which a light alignment layer was laminated. The polarization direction of the UV light was set to 45 degrees with respect to the longitudinal direction of the film.

The above-mentioned coating material for a polarizing film was applied to a light alignment layer, and a polarizing layer was similarly provided on a base film on which an alignment layer was laminated.

    [Polarizer Lamination Method C]         (Manufacture of substrate laminated polarizer)    

Using polyester X as a thermoplastic resin substrate, an unstretched film having a thickness of 100 μm was prepared, and one side of the unstretched film was coated with an aqueous solution of a polyvinyl alcohol having a polymerization degree of 2400 and a saponification degree of 99.9 mol% and dried to form PVA layer.

The obtained laminated body was stretched twice at 120 ° C between rolls having different peripheral speeds in the longitudinal direction and wound. Next, the obtained laminate was treated with a 4% aqueous boric acid solution for 30 seconds, and then dipped in a mixed aqueous solution of iodine (0.2%) and potassium iodide (1%) for 60 seconds to dye it, followed by potassium iodide (3%) and boric acid. (3%) of the mixed aqueous solution was treated for 30 seconds.

The laminate was uniaxially stretched in the long-side direction in a mixed aqueous solution of boric acid (4%) and potassium iodide (5%) at 72 ° C. Next, the stretched laminate was washed with a 4% potassium iodide aqueous solution, the aqueous solution was removed with an air knife, and then dried in an oven at 80 ° C. Both ends were cut and wound to obtain a substrate having a width of 30 cm and a length of 1000 m. Multilayer polarizer 1. The total extension magnification is 6.5 times, and the thickness of the polarizer is 5 μm. In addition, the substrate laminated polarizer 1 was embedded in an epoxy resin, and then a section was cut out, observed with an optical microscope, and the thickness was read.

    (Lamination of Polarizing Layer)    

After applying a UV-curable acrylic adhesive on the base film, the polarizing mirror surface of the base multilayer polarizer 1 is bonded, and ultraviolet rays are irradiated from the base multilayer polarizer 1 side to stack the base multilayer polarizer on the base film. 1. After that, the thermoplastic resin substrate is peeled to provide a polarizer on the substrate film.

    [Polarizer Lamination Method D]         (Manufacture of single-layer polarizer)    

A polyvinyl alcohol resin film having a degree of saponification of 99.9% was guided to a roll having a peripheral speed difference, and uniaxial stretching was performed at 100 ° C for 3 times. The obtained stretched polyvinyl alcohol stretched film was dyed in a mixed aqueous solution of potassium iodide (0.3%) and iodine (0.05%), and then uniaxially stretched 1.8 times in a 10% aqueous solution of boric acid at 72 ° C. After that, it was washed with water in ion-exchanged water, and then immersed in a 6% potassium iodide aqueous solution. After removing the aqueous solution with an air knife, it was dried at 45 ° C. to obtain a polarizer. The thickness of the polarizer is 18 μm.

    (Laminated Polarizers)    

After applying a UV-curable acrylic adhesive on the base film, a single-layer polarizer was bonded, ultraviolet rays were irradiated from the base laminated polarizer side, and a polarizer was set on the base film.

    (Lamination of the retardation layer)    

As a method of providing a retardation layer on a polarizer, the following four methods are performed.

(F) A method of providing a 1 / 2-wavelength layer and a 1 / 4-wavelength layer on a polarizer by coating (the lamination method F of a retardation layer)

(G) A method of transferring a 1 / 2-wavelength layer provided on a release film to a polarizer, and then transferring a 1 / 4-wavelength layer provided on the release film to the polarizer (layering method G of a retardation layer) )

(H) A method in which a 1/4 wavelength layer and a 1/2 wavelength layer are provided on a release film, and then transferred to a polarizer (layering method H of a retardation layer)

(I) A method in which a 1 / 2-wavelength layer is provided on a 1 / 4-wavelength layer by coating, and the 1 / 2-wavelength layer is bonded to a polarizer (a method of laminating a retardation layer I)

The details of each method are as follows.

    [Lamination method F of retardation layer]    

On the polarizer provided on the base film, polyvinyl alcohol (a 2% by mass aqueous solution of polyvinyl alcohol 1000 completely saponified (surfactant 0.2%)) was applied and dried to obtain polyvinyl alcohol having a thickness of about 100 nm. membrane. Next, the surface of the polyvinyl alcohol film is subjected to a rubbing treatment. The angle of the rubbing treatment is 15 degrees with respect to the absorption axis of the polarizer.

Next, a solution for forming a retardation layer having the following composition was applied to a surface subjected to a rubbing treatment by a bar coating method. The coated film is dried, and after being subjected to an orientation treatment, it is irradiated with ultraviolet rays to harden it to produce a 1/2 wavelength layer.

Solution for forming retardation layer

Next, a polyvinyl alcohol film was provided on the 1/2 wavelength layer in the same manner, and a rubbing treatment was performed. The angle of the rubbing treatment was 73 degrees with respect to the absorption axis of the polarizer. The retardation layer-forming solution was applied by a bar coating method, dried, and subjected to an orientation treatment, followed by irradiation with ultraviolet rays to harden it. A method of adjusting the thickness in a bar coating to form a 1/4 wavelength layer.

    [Lamination method G of retardation layer]    

A biaxially stretched polyethylene terephthalate (PET) film having a thickness of 50 μm was subjected to a rubbing treatment. The phase-difference layer-forming solution was applied to the rubbing surface by a rod coating method, dried, and subjected to an orientation treatment, and then irradiated with ultraviolet rays to harden it. A biaxially stretched polyethylene terephthalate film was provided. 1 / 2 wavelength layer. Next, a half-wavelength plane was bonded to a polarizer surface provided on the base film using an ultraviolet curing adhesive. After that, the biaxially stretched PET film was peeled. The lamination was performed so that it was 15 degrees with respect to the absorption axis of a polarizer.

In the same manner, a 1 / 4-wavelength layer was provided on the biaxially stretched PET film, and it was bonded to the previous 1 / 2-wavelength layer using a transparent adhesive sheet for optics. The bonding system was performed so that it might become 75 degrees with respect to the absorption axis of a polarizer.

    [Lamination method H of retardation layer]    

A biaxially stretched polyethylene terephthalate (PET) film having a thickness of 50 μm was subjected to a rubbing treatment. The phase-difference layer-forming solution was applied to the rubbing surface by a rod coating method, dried, and subjected to an orientation treatment, and then irradiated with ultraviolet rays to harden it. A biaxially stretched polyethylene terephthalate film was provided. 1 / 4 wavelength layer. Then, polyvinyl alcohol (a 2% by mass aqueous solution of polyvinyl alcohol 1000 completely saponified (surfactant 0.2%)) was applied to the 1/4 wavelength layer and dried to obtain a polyvinyl alcohol film having a thickness of about 100 nm. Next, the surface of the polyvinyl alcohol film was subjected to a rubbing treatment. The phase-difference layer-forming solution was applied to the friction-treated surface of PVA by a bar coating method and dried. After the orientation treatment was performed, it was irradiated with ultraviolet rays to harden it to form a 1/2 wavelength layer. This is performed so that the angle between the rubbing direction when the 1/4 wavelength layer is provided and the rubbing direction when the 1/2 wavelength layer is provided is 60 degrees. Furthermore, a half-wavelength plane was bonded to a polarizer surface provided on the base film using an ultraviolet curing adhesive. After that, the biaxially stretched PET film was peeled. The bonding is performed so that the rubbing direction of the absorption axis of the polarizer and the 1/2 wavelength layer becomes 15 degrees, and the rubbing direction of the 1/4 wavelength layer becomes 75 degrees.

    [Lamination method of phase difference layer I]    

The 1 / 4-wavelength film was rolled out from a roller having a 1 / 4-wavelength film having a slow axis in the length direction, a necessary length was cut, and the surface was rubbed. A 1/2 wavelength layer is provided on the rubbing surface in the same method as the method F for laminating a retardation layer. Further, a half-wavelength plane was bonded to a polarizer surface provided on the base film using an ultraviolet curing adhesive. The 1 / 4-wavelength film was produced by extruding a propylene-ethylene random copolymer (with an ethylene content of 5%) into a sheet shape, and then stretching it with a roller in the longitudinal direction (thickness: 20 μm). The lamination was performed such that the rubbing direction of the absorption axis of the polarizer and the 1/2 wavelength layer was 15 degrees, and the rubbing direction was 75 degrees from the slow axis direction of the 1/4 wavelength layer.

The thickness of the retardation layer formed by the coating is 1.2 μm in the 1/4 wavelength layer and 2.3 μm in the 1/2 wavelength layer. The thickness of the adhesive layer was 3 μm.

    [Examples 1 to 18]    

As shown in Table 2, a polarizer and a retardation layer were set on the substrate film by the method shown in Table 2 to make a circular polarizing plate.

    [Comparative Example 1]    

After the polarizer was laminated on the substrate film by the polarizer lamination method D, a TAC film with a thickness of 80 μm was adhered to the polarizer using a PVA adhesive to produce a polarizing plate. In addition, a retardation layer is provided on the TAC film of the polarizing plate by using the lamination method of the retardation layer I to make a circular polarizing plate.

    [Comparative Example 2]    

After the polarizer lamination method A is used to laminate the polarizer on the substrate film, a 1/2 wavelength film is laminated on the polarizer, and then a 1/4 wavelength film is laminated thereon. The 1 / 2-wavelength film is obtained by using a 1 / 4-wavelength film whose thickness is doubled, and each of the laminations is performed according to the lamination method I of the retardation layer. The 1 / 2-wavelength plate system has a state of 15 degrees with respect to the absorption axis of the polarizer, and the 1 / 4-wavelength plate system has a state of 75 degrees with respect to the absorption axis of the polarizer.

Table 2 shows the characteristics of the circular polarizing plates obtained in Examples 1 to 18 and Comparative Examples 1 to 2. In addition, the anti-reflection effect was ○ in all examples. In addition, the EL display device used for the anti-reflection effect was evaluated by visual observation without passing through polarized sunglasses. As a result, the EL display device having the circularly polarizing plate of each example did not observe a rainbow spot, and good visibility was obtained.

The flexibility characteristics of the circular polarizing plates obtained in Examples 1 to 18 and Comparative Examples 1 to 2 are shown in Table 3.

    (Production of coatings for circularly polarized reflective layers)    

A methyl ethyl ketone / cyclohexanone (95/5 mass ratio) solution having a solid content concentration of 5% having the following composition was prepared.

‧ 0.075 parts by mass of the following fluorinated compound (2)

    (Formation of a circularly polarized reflective layer)    

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

    (Evaluation of circularly polarizing plates laminated with circularly polarizing reflective layers)    

The circularly polarizing plate laminated with the circularly polarized reflective layer obtained above was similarly assembled to an EL display and visually observed. As a result, compared with the circularly polarizing plate of each embodiment without the circularly polarized reflective layer, the effect of improving brightness was confirmed. .

In addition, the operability and the bending resistance were evaluated in the same manner, and the results were all the same as those of the original examples.

The EL display device of the present invention uses a base film having a specific in-plane retardation so that the number of self-supporting films existing between the polarizer and the retardation layer is one or less. The 1/4 wavelength layer circularly polarizing plate serves as a retardation plate, so it has excellent visibility (suppression of iridescence), can be thinned, and it is unlikely to cause problems in the manufacturing process.

Moreover, in the case of a flexible EL display device, even when repeatedly folded or placed in a high-temperature state, the laminated members are not easily peeled from each other, and creases are hardly generated.

When a polyester film is used as the base film of the circular polarizing plate, an EL display device having a circular polarizing plate having excellent moisture permeability resistance, dimensional stability, mechanical strength, and chemical stability can be provided.

Claims (4)

    An electroluminescence display device is provided with an electroluminescence unit and a circularly polarizing plate arranged closer to a viewing side than the electroluminescence unit, and is characterized in that the circularly polarizing plate is in order With retardation layer, polarizer and substrate film, (1) the in-plane retardation of the substrate film is 3000 ~ 30,000 nm, (2) there is no self-supporting film between the polarizer and the retardation layer, or only 1 (The polarizer and the retardation layer here also include the retardation layer itself), and (3) the retardation layer has a 1/2 wavelength layer and a 1/4 wavelength layer.         The electroluminescent display device according to claim 1, wherein the thickness of the polarizer is 12 μm or less.         The electroluminescent display device according to claim 1 or 2, wherein the polarizer includes a polymerizable liquid crystal compound and a dichroic dye.         The electroluminescent display device according to any one of claims 1 to 3, wherein at least one of the half-wavelength layer and the quarter-wavelength layer includes a liquid crystal compound.