KR20180039649A - Polarizer with long optical phase compensation layer and organic EL panel using the same - Google Patents

Abstract

A polarizing plate with an optically compensating layer of a long-axis phase, which realizes excellent reflection color and viewing angle characteristics and which can be obtained with excellent manufacturing efficiency, is provided. The polarizing plate with an optical compensation layer of the present invention is an elongated phase and is used for an organic EL panel. This polarizing plate with an optical compensation layer has a longitudinal polarizer, a first optical compensation layer in a longitudinal direction and a second optical compensation layer in a longitudinal direction in this order. The absorption axis direction of the polarizer is substantially orthogonal or parallel to the longitudinal direction; Wherein the first optical compensation layer exhibits a refractive index characteristic of nx > ny > nz, Re (550) satisfies a relationship of Re 100 (550) 1 The angle formed by the slow axis of the optical compensation layer and the longitudinal direction is 35 ° to 55 °; The second optical compensation layer has a refractive index of nz > nx > ny, Re (550) of 5 nm to 20 nm, Rth (550) of -200 nm to 20 nm, Lt; RTI ID = 0.0 > and / or < / RTI >

Description

Polarizer with long optical phase compensation layer and organic EL panel using the same

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a polarizing plate having a long optical compensation layer and an organic EL panel using the polarizing plate.

Recently, a display (organic EL display device) on which an organic EL panel is mounted with the spread of a thin display has been proposed. Since the organic EL panel has a highly reflective metal layer, problems such as reflection of external light and reflection of background are likely to occur. Therefore, it is known to prevent such a problem by providing the circularly polarizing plate on the viewer side. As a general circular polarizing plate, it is known that a retardation film (typically, a quarter-wave plate) is laminated so that the slow axis thereof forms an angle of about 45 degrees with respect to the absorption axis of the polarizer. Further, attempts have been made to laminate a retardation film (optical compensation layer) having various optical properties to further improve the antireflection property. On the other hand, from the viewpoint of production efficiency, there is a demand for a circularly polarizing plate of an elongated phase (in particular, a roll-like) which can be produced by so-called roll-to-roll. However, in the production of the circularly polarizing plate by roll-to-roll, there is a possibility that the deviation of the optical axis of the optical film due to the bonding in the setting direction, the difficulty of controlling the slow axis in the oblique direction of the longitudinal phase retardation film (for example,? / 4 plate) And variations in characteristics in the width direction.

Patent Document 1: Japanese Patent No. 3325560

The main object of the present invention is to provide a polarizing plate with a long-axis optical compensation layer which realizes excellent reflection color and viewing angle characteristics and can be obtained with excellent manufacturing efficiency.

The polarizing plate with an optical compensation layer of the present invention is an elongated phase and is used for an organic EL panel. This polarizing plate with an optical compensation layer has a longitudinal polarizer, a first optical compensation layer in a longitudinal direction and a second optical compensation layer in a longitudinal direction in this order. The absorption axis direction of the polarizer is substantially orthogonal or parallel to the longitudinal direction; Wherein the first optical compensation layer exhibits a refractive index characteristic of nx > ny > nz, Re (550) of 100 nm to 180 nm, Nz coefficient of 1.0 to 2.0, Re (450) And the angle formed by the longitudinal axis of the first optical compensation layer and the slow axis is 35 ° to 55 °; And the second optical compensation layer exhibits a refractive index characteristic of nz > nx > ny, wherein Re (550) is in the range of 5 nm to 20 nm, Rth (550) is in the range of -200 nm to 20 nm, Are substantially orthogonal or parallel to the longitudinal direction. Herein, Re (450) and Re (550) indicate in-plane retardations measured with light at 450 nm and 550 nm at 23 ° C, respectively, and Rth (550) Phase difference.

In one embodiment, the polarizing plate with an optical compensation layer is wound in a roll form.

In one embodiment, the first optical compensation layer is a retardation film obtained by oblique stretching.

In one embodiment, the polarizing plate with an optical compensation layer further comprises a conductive layer and a substrate in this order on the side opposite to the first optical compensation layer of the second optical compensation layer.

According to another aspect of the present invention, an organic EL panel is provided. This organic EL panel has the above-described polarizing plate with an optical compensation layer cut to a predetermined size.

According to the present invention, it is possible to manufacture a polarizing plate with an optically compensating layer having a long optical axis by optimizing the combination of refractive index characteristics, in-plane retardation, thickness direction retardation, and slow axis direction of the two optical compensation layers to produce a roll- A polarizing plate with an optical compensation layer capable of realizing excellent reflection color and viewing angle characteristics can be obtained.

1 is a schematic cross-sectional view of a polarizing plate with an optical compensating layer according to an embodiment of the present invention.

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

(Definition of terms and symbols)

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

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

"nx" is the refractive index in the direction in which the in-plane refractive index becomes the maximum (that is, the slow axis direction), "ny" is the refractive index in the plane perpendicular to the slow axis Refractive index in the thickness direction.

(2) In-plane retardation (Re)

"Re (lambda)" is the in-plane retardation measured with light having a wavelength of lambda nm at 23 deg. Re (?) Can be obtained by the formula: Re = (nx-ny) xd, where d (nm) is the thickness of the layer (film). For example, "Re (550)" is an in-plane retardation measured at a wavelength of 550 nm at 23 deg.

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

"Rth (lambda)" is a retardation in the thickness direction measured by light having a wavelength of lambda nm at 23 deg. Rth (?) Can be obtained by the formula: Rth = (nx-nz) xd, where d (nm) is the thickness of the layer (film). For example, "Rth (550)" is a retardation in the thickness direction measured at a wavelength of 550 nm at 23 deg.

(4) Nz coefficient

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

(5) substantially orthogonal or parallel

The expression "substantially orthogonal" and "substantially orthogonal" includes the case where the angle formed by the two directions is 90 DEG +/- 10 DEG, preferably 90 DEG +/- 7 DEG, more preferably 90 DEG +/- 5 DEG to be. The expression "substantially parallel" and "approximately parallel" includes cases where the angle formed by the two directions is 0 DEG +/- 10 DEG, preferably 0 DEG +/- 7 DEG, more preferably 0 DEG +/- 5 DEG to be. Further, in the present specification, the term simply referred to as "orthogonal" or "parallel" may include a state substantially orthogonal or substantially parallel.

A. Overall Composition of Polarizer with Optical Compensation Layer

1 is a schematic cross-sectional view of a polarizing plate with an optical compensating layer according to an embodiment of the present invention. The polarizing plate 100 with an optical compensation layer of the present embodiment comprises a polarizer 10, a first optical compensation layer 30 and a second optical compensation layer 40 in this order. Practically, as shown in the drawing, a protective layer 20 may be provided on the opposite side of the first optical compensation layer 30 of the polarizer 10. Preferably, the polarizing plate 100 with an optical compensation layer does not include an optically anisotropic layer between the polarizer 10 and the first optical compensation layer 30. [ The optically anisotropic layer refers to a layer having an in-plane retardation Re (550) of more than 10 nm and / or a thickness direction retardation Rth (550) of less than -10 nm or more than 10 nm. Examples of the optically anisotropic layer include a liquid crystal layer, a retardation film, and a protective film. When the optical compensation layer-attached polarizing plate does not include an optically anisotropic layer, in one embodiment, the first optical compensation layer 30 can function as a protective layer of the polarizer. In another embodiment, a protective layer having optical isotropy (hereinafter referred to as a protective layer) is provided between the polarizer 10 and the first optical compensation layer 30 (i.e., on the side opposite to the protective layer 20 of the polarizer 10) (Also referred to as an inner protective layer: not shown) may be provided. The conductive layer and the substrate may be provided in this order on the opposite side of the first optical compensation layer 30 of the second optical compensation layer 40 (that is, outside the second optical compensation layer 40) (Neither of which is shown). The base material is closely adhered to the conductive layer. In the present specification, the term "closely adhered layer" means that two layers are laminated directly or by bonding without interposing an adhesive layer (for example, an adhesive layer or a pressure-sensitive adhesive layer). The conductive layer and the substrate are typically introduced into the optical compensation layer-attached polarizing plate 100 as a laminate of a substrate and a conductive layer. By further providing a conductive layer and a substrate, the polarizing plate 100 with an optical compensating layer can be preferably used for an inner touch panel type input display device.

Although not clearly shown in the figure, the polarizing plate with an optical compensation layer of the present embodiment is a long film. Thus, the components (e.g., the polarizer, the first and second optical compensation layers, the protective layer and, if present, the conductive layer and substrate) of the polarizing plate with optical compensation layer are also elongated. In one embodiment, the polarizing plate with an optical compensation layer is wound in a roll form. In the present specification, the term "elongated phase" means a long elongated shape having a sufficiently long length with respect to the width. For example, the elongated shape includes a elongated shape having a length of 10 times or more, preferably 20 times or more. Therefore, the polarizing plate 100 with an optical compensation layer can be obtained, for example, by changing the long-axis phase difference film constituting the long-axis polarizer 10 and the first optical compensation layer 30 and the long-axis phase difference film constituting the second optical compensation layer 40 And a laminate of a film and a protective film of an elongated phase constituting a protective layer, if necessary, by a roll-to-roll method. In the present specification, the term "roll-to-roll" refers to a process in which rolls of film are carried while being juxtaposed with each other in the longitudinal direction.

The absorption axis direction of the polarizer 10 is substantially orthogonal or parallel to the longitudinal direction. The first optical compensation layer 30 has a refractive index nx > ny > nz and a slow axis. In the present embodiment, the first optical compensation layer 30 has a slow axis in an oblique direction with respect to the longitudinal direction. Concretely, the angle formed by the slow axis of the first optical compensation layer 30 and the longitudinal direction is in the range of 35 to 55, preferably 38 to 52, more preferably 42 to 48, Preferably about 45 [deg.]. The absorption axis of the polarizer is expressed in the longitudinal direction or in the width direction due to the manufacturing method thereof. Therefore, the angle formed by the slow axis and the longitudinal direction of the first optical compensation layer 30 is equal to the angle between the slow axis of the first optical compensation layer 30 Can correspond to the angle formed by the absorption axis of the polarizer 10. When the angle is within this range, an excellent antireflection function can be realized. The first optical compensation layer 30 is typically composed of a retardation film obtained by oblique stretching. The second optical compensation layer 40 exhibits a refractive index characteristic of nz> nx> ny, and has a slow axis. The slow axis direction of the second optical compensation layer 40 is substantially orthogonal or parallel to the longitudinal direction. The slow axis of the second optical compensation layer 40 and the absorption axis of the polarizer 10 are substantially orthogonal to or parallel to each other and the slow axis of the second optical compensation layer 40 and the slow axis of the first optical compensation layer 30 The angle formed by the axis is 35 ° to 55 °, preferably 38 ° to 52 °, more preferably 42 ° to 48 °, and still more preferably about 45 °. The second optical compensation layer exhibiting a refractive index characteristic of nz > nx > ny is provided to improve the viewing angle characteristics of the polarizing plate with an optical compensation layer. Generally, the second optical compensation layer is formed by stretching, . On the other hand, since such a second optical compensation layer has anisotropy in the surface, the antireflection characteristic of the polarizing plate with an optical compensation layer may be influenced. In the second optical compensation layer of the elongated phase, the slow axis is substantially orthogonal to or parallel to the longitudinal direction, and the relationship with the slow axis direction of the first optical compensation layer is optimized, and the in- The effect of anisotropy in the plane can be reduced by optimization. In addition, as described above, when the relationship of the first optical compensation layer with the slow axis direction of the first optical compensation layer is optimized so as to reduce the effect of anisotropy in the second optical compensation layer surface, the angle becomes about 45 degrees. As a result, the angle formed by the slow axis of the first optical compensation layer and the absorption axis of the polarizer is 45 DEG, and the anti-reflection characteristic of the first optical compensation layer is extremely excellent. As a result, it becomes possible to achieve both excellent viewing angle characteristics and anti-reflection characteristics (for example, reflection color).

Hereinafter, each layer constituting the polarizing plate with an optical compensating layer and the optical film will be described in detail.

A-1. Polarizer

As the polarizer 10, any appropriate polarizer may be employed. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

As specific examples of the polarizer composed of the single-layer resin film, a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, and an ethylene / vinyl acetate copolymerization system partial saponification film may be coated with iodine or a dichroic dye A dyeing treatment with a dichroic substance and a stretching treatment, and a polyene-based oriented film such as a dehydrated product of PVA and a dehydrochlorinated product of polyvinyl chloride. Preferably, a polarizer obtained by dying a PVA-based film with iodine and uniaxially stretching is used because it has excellent optical properties.

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

Specific examples of the polarizer obtained by using the laminate include a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA resin layer formed on the resin substrate And a polarizer obtained by using a laminate. A polarizer obtained by using a laminate of a resin substrate and a PVA resin layer formed on the resin substrate is obtained by, for example, applying a PVA resin solution to a resin substrate and drying the PVA resin layer to form a PVA resin layer on the resin substrate, To obtain a laminate of a substrate and a PVA-based resin layer; And stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In the present embodiment, the stretching typically includes immersing the laminate in an aqueous solution of boric acid and stretching. In addition, the stretching may further include, if necessary, air-stretching the laminate at a high temperature (for example, 95 캜 or higher) before stretching in an aqueous solution of boric acid. The obtained resin substrate / polarizer laminate may be used as is (that is, the resin substrate may be used as a protective layer of the polarizer), the resin substrate is peeled from the laminate of resin substrate / polarizer, And any suitable protective layer may be laminated thereon. Details of the method for producing such a polarizer are described, for example, in Japanese Patent Laid-Open Publication No. 7-73580. This publication is incorporated herein by reference in its entirety.

The thickness of the polarizer is preferably 25 占 퐉 or less, more preferably 1 占 퐉 to 12 占 퐉, still more preferably 3 占 퐉 to 12 占 퐉, and particularly preferably 3 占 퐉 to 8 占 퐉. When the thickness of the polarizer is in this range, the curl at the time of heating can be suppressed well and the appearance durability at the time of heating can be obtained.

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

A-2. The first optical compensation layer

As described above, the first optical compensation layer 30 exhibits a refractive index characteristic of nx> ny≥nz. The in-plane retardation Re (550) of the first optical compensation layer is 100 nm to 180 nm, preferably 110 nm to 170 nm, and more preferably 120 nm to 160 nm. When the in-plane retardation of the first optical compensation layer is in this range, the slow axis direction of the first optical compensation layer is set to an angle of 35 to 55 degrees (particularly about 45 degrees) with respect to the absorption axis direction of the polarizer as described above An excellent reflection preventing function can be realized.

The first optical compensation layer exhibits the wavelength dependency of so-called reverse dispersion. Specifically, the in-plane retardation satisfies a relation of Re (450) < Re (550). By satisfying this relationship, it is possible to achieve an excellent reflection color. Re (450) / Re (550) is preferably 0.8 or more and less than 1, and more preferably 0.8 or more and 0.95 or less.

The Nz coefficient of the first optical compensation layer is 1.0 to 2.0, preferably 1.0 to 1.5, and more preferably 1.0 to 1.3. By satisfying this relationship, a more excellent reflection color can be achieved.

The deviation of the in-plane retardation Re (550) in the width direction of the first optical compensation layer is preferably 20% or less, more preferably 10% or less, further preferably 5% or less. The smaller the deviation, the better. This is because the defects caused by the fusion of the roll-to-roll can be satisfactorily suppressed with respect to the antireflection properties of the obtained polarizing plate with an optical compensation layer. In the present specification, "deviation of in-plane retardation" refers to a maximum value of deviation with respect to the in-plane retardation set.

The deviation in the slow axis direction in the width direction of the first optical compensation layer is preferably 5 DEG or less, more preferably 3 DEG or less, and still more preferably 1 DEG or less. The smaller the deviation, the better. This is because, similarly to the case of the in-plane retardation deviation in the width direction, defects due to the adhesion of the roll-to-roll can be satisfactorily suppressed with respect to the antireflection properties of the obtained polarizing plate with an optical compensation layer. Further, the "deviation in the ground axial direction" refers to the maximum value of the deviation with respect to the set ground axial direction.

The absorption rate of the first optical compensation layer is preferably 3% or less, more preferably 2.5% or less, further preferably 2% or less. By satisfying the absorption rate as described above, it is possible to suppress the change of the display characteristics with time. The water absorption can also be obtained according to JIS K 7209.

The first optical compensation layer is typically a retardation film formed of any suitable resin. As the resin for forming the retardation film, a polycarbonate resin is preferably used.

As the polycarbonate resin, any suitable polycarbonate resin can be used as long as the effect of the present invention can be obtained. Preferably, the polycarbonate resin is obtained by copolymerizing a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, an alicyclic diol, alicyclic dimethanol, di-tri or polyethylene glycol, , A structural unit derived from at least one dihydroxy compound selected from the group consisting of alkylene glycols and spiroglycols. Preferably, the polycarbonate resin is obtained by copolymerizing a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from an alicyclic dimethanol and / A structural unit derived from polyethylene glycol; More preferably a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from a di-tri or polyethylene glycol. The polycarbonate resin may contain a structural unit derived from another dihydroxy compound, if necessary. Details of the polycarbonate resin that can be preferably used in the present invention are described in, for example, Japanese Patent Laid-open Publication No. 2014-10291 and Japanese Laid-Open Patent Publication No. 2014-26266, the disclosure of which is incorporated herein by reference .

The polycarbonate resin preferably has a glass transition temperature of 110 ° C or higher and 180 ° C or lower, more preferably 120 ° C or higher and 165 ° C or lower. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, and there is a possibility of causing a dimensional change after the film is formed, and the image quality of the resulting organic EL panel may be lowered. If the glass transition temperature is excessively high, the molding stability at the time of film forming may deteriorate, and transparency of the film may be deteriorated. The glass transition temperature can be determined in accordance with JIS K 7121 (1987).

The molecular weight of the polycarbonate resin can be represented by the reduced viscosity. The reduced viscosity was measured by using a Ubbelode viscosity tube at a temperature of 20.0 DEG C +/- 0.1 DEG C by precisely adjusting the polycarbonate concentration to 0.6 g / dL using methylene chloride as a solvent. The lower limit of the reduced viscosity is usually 0.30 dL / g, more preferably 0.35 dL / g or more. The upper limit of the reduced viscosity is usually 1.20 dL / g, more preferably 1.00 dL / g, and still more preferably 0.80 dL / g. If the reduced viscosity is lower than the above lower limit value, the mechanical strength of the molded article may be decreased. On the other hand, when the reduced viscosity is larger than the upper limit value, the fluidity at the time of molding is lowered, and productivity and formability are deteriorated in some cases.

The retardation film is typically produced by stretching the resin film in at least one direction.

As a method of forming the resin film, any suitable method can be employed. Examples thereof include a melt extrusion method (e.g., a T-die molding method), a cast coating method (e.g., a casting method), a calender molding method, a hot press method, a coextrusion method, a co-melting method, a multilayer extrusion method and an inflation molding method. Preferably, a T-die molding method, a softening method, and an inflation molding method can be used.

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

The stretching may be carried out by any suitable stretching method, stretching conditions (e.g., stretching temperature, stretching magnification, stretching direction). Concretely, various stretching methods such as free-standing elongation, fixed-end elongation free-end shrinkage, and fixed-end shrinkage may be used alone or simultaneously or sequentially. The stretching direction can also be performed in various directions and dimensions such as the horizontal direction, the vertical direction, the thickness direction, and the diagonal direction. The stretching temperature is preferably Tg-30 ° C to Tg + 60 ° C, more preferably Tg-10 ° C to Tg + 50 ° C, relative to the glass transition temperature (Tg) of the resin film.

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

In one embodiment, the retardation film is produced by obliquely stretching a resin film in a longitudinal direction continuously in the direction of the angle? With respect to the longitudinal direction. By adopting oblique stretching, a stretched film of elongated shape having an orientation angle (a slow axis in the direction of the angle?) With respect to the longitudinal direction of the film can be obtained. For example, in the lamination with a polarizer, - It is possible to roll, and the manufacturing process can be simplified. The absorption axis of the polarizer is expressed in the longitudinal direction or the width direction of the elongated film due to the production method thereof, and therefore the angle? May be an angle formed by the absorption axis of the polarizer and the slow axis of the first optical compensation layer.

Examples of the stretching machine used for oblique stretching include a tenter stretcher capable of imparting a feed force or a pulling force or a pulling force at a different speed in the lateral and / or longitudinal direction. As the tenter-type stretching machine, there are a transverse uniaxial stretching machine and a simultaneous biaxial stretching machine. However, any suitable stretching machine can be used as long as it can obliquely stretch the longitudinally stretched resin film.

The thickness of the retardation film (stretched film, that is, the first optical compensation layer) is preferably 20 to 100 占 퐉, more preferably 20 to 80 占 퐉, and still more preferably 20 to 65 占 퐉. With such a thickness, the desired in-plane retardation and thickness retardation can be obtained.

A-3. The second optical compensation layer

As described above, the second optical compensation layer 40 exhibits a refractive index characteristic of nz> nx> ny. By providing the second optical compensation layer having such optical characteristics, the reflection hue when viewed in the oblique direction is remarkably improved, and consequently, the polarizing plate with optical compensation layer having very excellent viewing angle characteristics can be obtained.

The in-plane retardation Re (550) of the second optical compensation layer is 5 nm to 20 nm, preferably 5 nm to 15 nm, and more preferably 5 nm to 10 nm. When the in-plane retardation is in this range, there is an advantage that a very excellent viewing angle characteristic and reflection color can be compatible with each other.

The retardation Rth (550) in the thickness direction of the second optical compensation layer is -200 nm to -20 nm, preferably -180 nm to -40 nm, and more preferably -180 nm to -60 nm. When the phase difference in the thickness direction is in this range, it has the advantage that both the excellent viewing angle characteristics and the reflection color can be compatible with each other as in the case of optimizing the in-plane retardation.

The second optical compensation layer may be formed of any suitable material. Preferably, the second optical compensation layer may be composed of a retardation film formed of a fumaric acid diester-based resin described in Japanese Patent Laying-Open No. 2012-32784. The thickness of the second optical compensation layer is preferably from 5 탆 to 80 탆, more preferably from 10 탆 to 50 탆.

A-4. The laminate

The in-plane retardation Re (550) of the laminate of the first optical compensation layer and the second optical compensation layer is 120 nm to 160 nm, preferably 130 nm to 150 nm. The thickness direction retardation Rth (550) of the laminate is -40 nm to 100 nm, preferably -20 nm to 50 nm. By setting the optical characteristics of the laminate as described above, the reflection hue when viewed in the oblique direction is remarkably improved, and consequently, the polarizing plate with optical compensation layer having very excellent viewing angle characteristics can be obtained.

A-5. Protective layer

The protective layer 20 is formed of any suitable film that can be used as the protective layer of the polarizer. Specific examples of the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based resins, polyvinyl alcohol-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, polyether sulfone- And transparent resins such as phenol, polystyrene, polynorbornene, polyolefin, (meth) acrylic, and acetate. Further, thermosetting resins such as (meth) acrylic resins, urethane resins, (meth) acrylic urethane resins, epoxy resins and silicon resins, and ultraviolet curing resins can also be used. Other examples include glassy polymers such as siloxane polymers. A polymer film described in Japanese Patent Laid-Open No. 2001-343529 (WO 01/37007) can also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a phenyl group and a substituted or unsubstituted phenyl group and / or nitrile group in the side chain can be used. And a resin composition having an alternating copolymer composed of methylmaleimide and an acrylonitrile styrene copolymer. The polymer film may be, for example, an extrusion molded article of the resin composition.

The protective layer 20 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and antiglare treatment, if necessary. In addition, the protective layer 20 may be provided with a treatment for improving the visibility in the case of visually observing through polarized sunglasses as required (typically providing a (other) circular polarization function, giving a super high retardation) May be performed. By performing such processing, excellent visibility can be realized even when a display screen is viewed through a polarizing lens such as polarizing sunglasses. Therefore, the polarizing plate with an optical compensating layer can be preferably applied to an image display apparatus which can be used outdoors.

The thickness of the protective layer 20 is typically 5 mm or less, preferably 1 mm or less, more preferably 1 to 500 占 퐉, and further preferably 5 to 150 占 퐉. When the surface treatment is performed, the thickness of the protective layer includes the thickness of the surface treatment layer.

When the inner protective layer is provided between the polarizer 10 and the first optical compensation layer 30, it is preferable that the inner protective layer is optically isotropic as described above. In the present specification, "optically isotropic" means that the in-plane retardation Re 550 is 0 nm to 10 nm and the retardation Rth (550) in the thickness direction is -10 nm to + 10 nm. The inner protective layer may be composed of any suitable material as long as it is optically isotropic. The material may be suitably selected from the materials described above with respect to the protective layer 20, for example.

The thickness of the inner protective layer is preferably 5 mu m to 200 mu m, more preferably 10 mu m to 100 mu m, and still more preferably 15 mu m to 95 mu m.

A-6. The conductive layer or the base-

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

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

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

The conductive layer may be transferred from the base material to the second optical compensation layer so that the conductive layer alone serves as a constituent layer of the polarizing plate with an optical compensating layer or may be laminated on the second optical compensation layer as a laminate (substrate- do. Typically, as described above, the conductive layer and the substrate may be introduced into the polarizing plate with an optical compensating layer as a conductive layer with a substrate.

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

Preferably, the substrate is optically isotropic, and thus the conductive layer can be used as an isotropic substrate-attached conductive layer in an optical compensation layer-attached polarizer. Examples of the material constituting the optically isotropic base material (isotropic base material) include a material having a principal skeleton of a resin having no conjugated system such as norbornene resin or olefin resin, a lactone ring, a cyclic ring such as a glutarimide ring, And a material having a structure in the main chain of the acrylic resin. The use of such a material makes it possible to suppress the occurrence of the retardation depending on the orientation of the molecular chains when the isotropic substrate is formed.

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

A-7. Other

Any suitable pressure-sensitive adhesive layer or adhesive layer is used for the lamination of the layers constituting the polarizing plate with an optical compensation layer of the present invention. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive. The adhesive layer is typically formed of a polyvinyl alcohol-based adhesive.

Although not shown, a pressure sensitive adhesive layer may be provided on the second optical compensation layer 40 side of the polarizing plate 100 with an optical compensation layer. Since the pressure-sensitive adhesive layer is provided in advance, it can be easily attached to another optical member (for example, an organic EL cell). It is preferable that a release film be adhered to the surface of the pressure-sensitive adhesive layer until use.

B. Manufacturing Method

As a method for producing the polarizing plate with an optical compensating layer, a roll-to-roll can be typically employed. For example, the polarizing plate with an optical compensating layer is provided with a long resin film, a polarizer having a long axis in the longitudinal direction and an absorption axis in the longitudinal direction, and a long phase retardation film constituting the first optical compensating layer, And the second optical compensation layer is coated on the surface of the first optical compensation layer while the laminated film is being conveyed. The protective layer, the polarizer and the first optical compensation layer may be laminated at the same time, or the protective layer and the polarizer may be laminated first, or the polarizer and the first optical compensation layer may be laminated first. Further, a laminate of the first optical compensation layer and the second optical compensation layer may be formed first, and the laminate may be provided in the laminate. Here, the angle formed by the absorption axis of the polarizer 10 and the slow axis of the first optical compensation layer 30 is 35 ° to 55 °, preferably 38 ° to 52 °, as described above, 42 DEG to 48 DEG, and more preferably about 45 DEG.

In the present embodiment, the long-axis phase difference film constituting the first optical compensation layer has a slow axis in the oblique direction (for example, in the direction of the angle?) With respect to the longitudinal direction as described above. The angle? May be an angle formed between the absorption axis of the polarizer and the slow axis of the first optical compensation layer. Such a retardation film can be obtained by oblique stretching as described above. By using such a retardation film, it is possible to roll-to-roll in the production of a polarizing plate with an optical compensating layer, whereby the manufacturing process can be remarkably shortened.

C. Organic EL panel

The optically compensating polarizing plate with a long optical axis described in the above items A and B can be cut to a predetermined size and applied to an organic EL panel. Therefore, the present invention includes an organic EL panel using such a polarizing plate with an optical compensation layer. The organic EL panel of the present invention comprises the organic EL cell and the polarizing plate with the optical compensation layer cut to a predetermined size on the visible side of the organic EL cell. The polarizing plate with an optical compensation layer is laminated such that the second optical compensation layer is on the organic EL cell side (the polarizer is on the viewer side).

Example

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

(1) Thickness

The measurement was carried out using a dial gauge (product name "DG-205" manufactured by PEACOCK Co., Ltd., dial gauge stand (product name "pds-2")).

(2) Phase difference

A sample of 50 mm x 50 mm was cut out from each optical compensation layer to obtain a measurement sample, which was measured using Axoscan manufactured by Axometrics. The measurement wavelength was 450 nm and 550 nm, and the measurement temperature was 23 deg.

Further, an average refractive index was measured using an Abbe's refractometer manufactured by Atago Co., and refractive indices nx, ny and nz were calculated from the obtained retardation values.

(3) Phase difference value and deviation in the direction of the ground axis

Five samples of 50 mm x 50 mm were cut at regular intervals in the width direction of the film roll constituting the first optical compensation layer. For the cut samples, the in-plane retardation Re (550) and the slow axis were obtained using Axoscan manufactured by Axometrics. The maximum value (%) of the deviation with respect to the set phase difference was regarded as a deviation of the phase difference value, and the maximum value () of the deviation with respect to the set ground axis direction was determined as the deviation in the slow axis direction.

(4) Absorption rate

Quot; Test Method of Water Absorption Rate and Boiling Water Absorption Rate of Plastics &quot; described in JIS K7209. The size of the test piece was found to be a square having a size of about 50 mm. The test piece was immersed in water having a water temperature of 25 캜 for 24 hours, and the change in weight before and after immersion was measured. The unit is%.

(5) Reflection color and viewing angle characteristics

A black image was displayed on the obtained organic EL panel, and the reflection hue was measured using a conoscopic viewing angle measurement evaluation device manufactured by Auoronic-MERCHERS. The "viewing angle characteristic" indicates the distance between the two reflected points of the reflection color in the front direction and the reflection color in the oblique direction (the maximum value or the minimum value at a polar angle of 45 degrees) in the xy chromaticity diagram of the CIE color system. If? Xy is smaller than 0.15, the viewing angle characteristic is evaluated to be good.

(6) Front reflectance

A black image was displayed on the obtained organic EL panel, and the front reflectance was measured using a spectroscopic colorimeter CM-2600d manufactured by Konica Minolta. When the reflectance is less than 20 (%), it is evaluated that the reflection characteristic is good.

[Example 1]

(Production of polycarbonate resin film)

Polymerization was carried out using a batch polymerization apparatus composed of two vertical reactors having agitation blades and a reflux condenser controlled at 100 캜. (BHEPF), isosorbide (ISB), diethylene glycol (DEG), diphenyl carbonate (DPC), and magnesium acetate tetrahydrate were prepared by moles of 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene BHEPF / ISB / DEG / DPC / magnesium acetate = 0.348 / 0.490 / 0.162 / 1.005 / 1.00 × 10 ^-5 . The interior of the reactor was sufficiently purged with nitrogen (oxygen concentration 0.0005 to 0.001 vol%) and heated with a heating medium. When the internal temperature reached 100 占 폚, stirring was started. After 40 minutes from the start of the temperature rise, the internal temperature was reached to 220 ° C, and the pressure was controlled to maintain this temperature, and the pressure was reduced to 13.3 kPa for 90 minutes after reaching 220 ° C. The phenol vapor produced as a byproduct together with the polymerization reaction was led to a reflux condenser at 100 ° C, the monomer component slightly contained in the phenol vapor was returned to the reactor, and the condensed phenol vapor was recovered by being led to a condenser at 45 ° C.

Nitrogen was introduced into the first reactor and once pressurized to atmospheric pressure, the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Then, the temperature rise and the decompression in the second reactor were started, and the internal temperature was set to 240 캜 and the pressure was set to 0.2 kPa for 50 minutes. Thereafter, the polymerization was allowed to proceed until a predetermined stirring power was reached. ISB / DEG = 34.8 / 49.0 / 16.2 [mol%] was obtained by introducing nitrogen into the reactor at a point of time when the predetermined power was reached and causing the reaction mixture to be evacuated in the form of strands and pelletized with a rotary cutter. Of a polycarbonate resin having a copolymerized composition. The polycarbonate resin had a reduced viscosity of 0.430 dL / g and a glass transition temperature of 128 캜.

(Fabrication of first optical compensation layer)

The polycarbonate resin thus obtained was vacuum-dried at 80 DEG C for 5 hours and then subjected to vacuum drying using a single screw extruder manufactured by Isuzu Chemical Co., screw diameter 25 mm, cylinder setting temperature 220 DEG C) T die (width 900 mm, set temperature 220 DEG C) A polycarbonate resin film having a thickness of 130 占 퐉 was prepared using a film-forming apparatus equipped with a chill roll (setting temperature: 125 占 폚) and a winder. The absorption rate of the obtained polycarbonate resin film was 1.2%.

The polycarbonate resin film thus obtained was subjected to oblique stretching in the same manner as in Example 1 of Japanese Patent Laid-Open No. 2014-194483 to obtain a retardation film.

A specific production procedure of the retardation film is as follows: A polycarbonate resin film (thickness 130 탆, width 765 mm) was preheated to 142 캜 in the preheating zone of the stretching apparatus. In the preheating zone, the clip pitch of the right and left clips was 125 mm. Next, as the film enters the first oblique stretching zone C1, the increase of the clip pitch of the right clip is started, and the film is increased from 125 mm to 177.5 mm in the first oblique stretching zone C1. The change rate of the clip pitch was 1.42. With respect to the clip pitch of the left clip in the first oblique stretching zone C1, the decrease of the clip pitch was started and decreased from 125 mm to 90 mm in the first oblique stretching zone C1. The change rate of the clip pitch was 0.72. In addition, as the film entered the second oblique stretching zone C2, the increase in the clip pitch of the left clip was started and increased from 90 mm to 177.5 mm in the second oblique stretching zone C2. On the other hand, the clip pitch of the right clip was maintained at 177.5 mm in the second oblique stretching zone C2. Further, at the same time as the oblique stretching, the stretching was also performed in the width direction by 1.9 times. The oblique stretching was performed at 135 캜. Next, MD shrinkage treatment was carried out in the shrink zone. Concretely, the clip pitches of the left and right clips were reduced from 177.5 mm to 165 mm together. The shrinkage rate in MD shrinkage treatment was 7.0%.

Thus, a retardation film (thickness: 40 mu m) was obtained. Re (550) of the obtained retardation film was 147 nm, Rth (550) was 167 nm (nx: 1.5977, ny: 1.59404, nz: 1.5935), and nx> ny = nz. Re (450) / Re (550) of the obtained retardation film was 0.89. The slow axis direction of the retardation film was 45 DEG with respect to the longitudinal direction. The in-plane retardation Re (550) of the retardation film was 4 nm, the deviation of the retardation in the width direction was 20%, and the deviation of the orientation angle in the width direction (direction of the slow axis) was 2 占.

(Fabrication of Second Optical Compensation Layer)

(Metolose 60SH-50, manufactured by Shin-Etsu Chemical Co., Ltd.), 600 g of distilled water, 358 g of diisopropyl fumarate, 0.1 g of diethyl fumarate (11.7 parts by weight based on 100 parts by weight of diisopropyl fumarate), 10 g of methyl isobutyl ketone (2.4 parts by weight based on 100 parts by weight of the total of diisopropyl fumarate and diethyl fumarate) and tert-butyl peroxy 3.1 g of the pearl rate was added, followed by nitrogen bubbling for 1 hour, followed by stirring at 400 rpm at 50 캜 for 24 hours to carry out suspension radical polymerization. After completion of the polymerization reaction, the contents were recovered in the reactor, the polymer was separated by filtration, washed 5 times with 2000 g of distilled water, washed 5 times with 2000 g of methanol and vacuum-dried at 80 DEG C for 6 hours to obtain 310 g of a fumaric acid diester polymer.

The obtained fumaric acid diester was dissolved in MIBK, the coating solution was coated on PET, and dried at 80 ° C for 5 minutes and further at 130 ° C for 5 minutes to prepare a retardation layer (nz> nx = ny). Further, by drawing treatment, a retardation layer having a refractive index characteristic of nz> nx> ny was formed, and this retardation layer was used as a second optical compensation layer.

(Preparation of laminate)

After the retardation layer (second optical compensation layer) is bonded to the retardation film (first optical compensation layer) by a roll-to-roll via an acrylic pressure-sensitive adhesive, the base film is removed to form a retardation film The second optical compensation layer) was transferred.

(Production of Polarizer)

A long roll of a polyvinyl alcohol (PVA) based resin film (manufactured by Kuraray Co., Ltd., product name "PE3000") having a thickness of 30 탆 was uniaxially stretched in the longitudinal direction by a roll stretching machine so as to be 5.9 times in the longitudinal direction, , Cross-linking, and washing treatments were carried out, and finally a drying treatment was carried out to produce a polarizer having a thickness of 12 탆.

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

(Production of polarizing plate)

An HC-TAC film (thickness: 32 탆, corresponding to the protective layer) having a hard coat (HC) layer formed on one side of the TAC film by a hard coat treatment was laminated on one side of the polarizer with a polyvinyl alcohol- - roll to obtain a long polarizing plate having a protective layer / polarizer configuration.

(Production of polarizing plate with optical compensation layer)

The polarizing surface of the polarizing plate thus obtained and the first optical compensation layer surface of the laminate of the first optical compensation layer / second optical compensation layer obtained above were laminated by roll-to-roll bonding with an acrylic pressure sensitive adhesive to form a protective layer / polarizer / A long polarizing optical compensation layer-attached polarizing plate having the configuration of the first optical compensation layer / the second optical compensation layer was obtained.

(Fabrication of organic EL panel)

A pressure-sensitive adhesive layer was formed on the second optical compensation layer side of the obtained polarizing plate with an optical compensation layer with an acrylic pressure-sensitive adhesive, and cut into a size of 50 mm x 50 mm.

The Galaxy-S5, a smartphone manufactured by Samsung Corporation, was disassembled and the organic EL panel was taken out. The polarizing film adhered to the organic EL panel was peeled off, and instead, the polarizing plate with the optically compensating layer cut off as described above was stuck to obtain an organic EL panel.

The reflection characteristics of the obtained organic EL panel were measured in the order of (5) above. As a result, it was confirmed that a neutral reflection color was realized in either the front direction or the oblique direction. Table 1 also shows the results of viewing angle characteristics and front reflectance.

[Table 1]

[Examples 2 to 5 and Comparative Examples 1 to 3]

A polarizing plate with an optical compensating layer and an organic EL panel were fabricated as shown in Table 1. The resulting polarizing plate with an optical compensation layer and an organic EL panel were provided for the same evaluation as in Example 1. As shown in Table 1, the organic EL panels of Examples 2 to 5 exhibited favorable viewing angle characteristics and frontal reflectance. It is also confirmed that a neutral reflection hue can be realized in both the front direction and the oblique direction with respect to these organic EL panels. On the other hand, the front reflectivity of the organic EL panels of Comparative Examples 1 to 3 was insufficient, and the antireflection characteristics were insufficient.

Industrial availability

The polarizing plate with an optical compensation layer of the present invention is preferably used for an organic EL panel.

10: Polarizer
20: Protective layer
30: first optical compensation layer
40: second optical compensation layer
100: Polarizing plate with optical compensation layer

Claims (5)

A long-axis polarizer, a first optical compensation layer of a long-axis phase and a second optical compensation layer of a long-axis phase in this order,
The absorption axis direction of the polarizer is substantially orthogonal or parallel to the longitudinal direction,
Wherein the first optical compensation layer exhibits a refractive index characteristic of nx > ny &gt; nz, a Re (550) of 100 nm to 180 nm, an Nz coefficient of 1.0 to 2.0, Re (450) Wherein an angle formed by the slow axis of the first optical compensation layer and the longitudinal direction is in the range of 35 [deg.] To 55 [
Wherein the second optical compensation layer exhibits a refractive index characteristic of nz>nx> ny, wherein Re (550) is 5 nm to 20 nm and Rth (550) is -200 nm to -20 nm, and the second optical compensation layer Are substantially orthogonal or parallel to the longitudinal direction,
Which can be used for an organic EL panel,
Polarizer with optically compensating layer of elongated phase.
(Where Re (450) and Re (550) respectively represent the in-plane retardation measured at 450 nm and 550 nm at 23 DEG C and Rth (550) Lt; / RTI &gt; The method according to claim 1,
A polarizing plate with a long optical phase compensation layer wound in a roll form. 3. The method according to claim 1 or 2,
Wherein the first optical compensation layer is a retardation film obtained by obliquely stretching. 4. The method according to any one of claims 1 to 3,
And a conductive layer and a substrate on the side opposite to the first optical compensation layer of the second optical compensation layer in this order. An organic EL panel comprising a polarizing plate with an optical compensating layer cut to a predetermined size according to any one of claims 1 to 4.

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