KR102681626B1 - Image display device and manufacturing method thereof - Google Patents

Abstract

The image display device includes a polarizing plate 36 bonded to the surface of the image display cell 10 via an adhesive layer 39. The polarizing plate includes a polarizer 31 and a retardation film 35, and the retardation film is disposed between the polarizer and the image display cell. The in-plane birefringence of the retardation film at a wavelength of 550 nm is 8×10 ^-3 or more. The angle (θ ₁ ) between the absorption axis direction of the polarizer and the slow axis direction of the retardation film when the polarizing plate is bonded to the image display cell through an adhesive layer, and the polarizer when the polarizing plate is peeled from the image display cell The absolute value (|θ ₁ -θ ₂ |) of the difference between the angle (θ ₂ ) formed by the absorption axis direction and the slow axis direction of the retardation film is preferably 0.4° or less.

Description

Image display device and manufacturing method thereof

The present invention relates to an image display device including a polarizing plate in which a polarizer and a retardation film are laminated on the surface of an image display cell, and a method for manufacturing the same.

Liquid crystal displays and organic EL displays are widely used as various image display devices such as mobile devices such as cell phones, smartphones, and tablet terminals, automotive devices such as car navigation devices, monitors for personal computers, and televisions. A liquid crystal display device has polarizers disposed on both sides of a liquid crystal cell based on its display principle. A retardation film may be disposed between the liquid crystal cell and the polarizer for the purpose of performing optical compensation such as improving contrast or expanding the viewing angle. In an organic EL display device, a circular polarizer (a polarizer and a retardation film with a 1/4 wavelength retardation) is placed on the surface of the visible side of the cell to suppress external light from being reflected from the metal electrode (cathode) and viewed as a mirror surface. Laminate) may be placed.

A polarizing plate generally has a structure in which a transparent protective film (polarizer protective film) is bonded to one or both sides of a polarizer, and a retardation film may be used as the transparent protective film. In addition, there are cases where a transparent protective film is bonded to the surface of the polarizer, and a retardation film is bonded thereon. A polarizing plate in which a polarizer and a retardation film are laminated is generally bonded to a substrate on the surface of an image display cell through an adhesive.

If the optical properties of the retardation film disposed between the polarizer and the image display cell are non-uniform within the plane, unevenness will occur in the displayed image, so the retardation film is required to have uniformity in film thickness and optical properties. For example, Patent Document 1 discloses a technology for equalizing the optical axis direction of the retardation film.

It is known that when an image display device is exposed to a high-temperature and high-humidity environment or to rapid environmental changes, display unevenness occurs due to changes in the optical properties of the retardation film or deterioration of the polarizer, etc., and it is difficult to provide a polarizer in which changes in optical properties are unlikely to occur. Various methods are being proposed for this purpose.

Japanese Patent Publication No. 2016-109924

Demand for lighter and thinner displays is increasing, and retardation films with smaller thicknesses than before are being used. Since the retardation of the retardation film is the product of birefringence and thickness, in order to cope with thinning, it is necessary to increase the birefringence of the retardation film by using a highly birefringent material or increasing the draw ratio.

In addition to lighter and thinner displays, displays are becoming more bright and have higher image quality, and fine defects and stains that were not visible before are becoming a quality issue. When a polarizing plate in which a polarizer and a retardation film with high birefringence are laminated is bonded to an image display cell through an adhesive, spots may be visible in the displayed image of the image display device, even though the polarizing plate itself has high optical uniformity. .

Such display stains are different from stains caused by non-uniformity of optical properties, or stains caused by changes over time or environmental changes in high temperature, high humidity environments, etc., and there is no knowledge regarding the cause of their occurrence or guidance for solving them. In view of the above, the purpose of the present invention is to provide an image display device that has a polarizing plate in which a highly birefringent retardation film and a polarizer are laminated, and in which unevenness of a displayed image is reduced.

The image display device of the present invention includes a polarizing plate bonded to the surface of an image display cell through an adhesive layer. The polarizing plate includes a polarizer and a retardation film, and the retardation film is disposed between the polarizer and the image display cell. The in-plane birefringence of the retardation film at a wavelength of 550 nm is 8×10 ^-3 or more.

A retardation film having an in-plane birefringence of 8×10 ^-3 or more at a wavelength of 550 nm is laminated on one side of the polarizer, and an adhesive polarizing plate with an adhesive layer laid on the retardation film is bonded to an image display cell to form an image display device. In a polarizing plate with an adhesive, the retardation film may be in contact with the adhesive layer.

The adhesive layer provided on the retardation film may have a shear storage modulus (G') divided by the thickness (D) (G'/D) of 5 kPa/㎛ or more at a temperature of 25°C. The thickness of the adhesive layer may be 25 μm or less.

The lamination pressure when bonding a polarizing plate with an adhesive to an image display cell is preferably 0.05 to 0.4 MPa.

The in-plane retardation of the retardation film may be 200 nm or more. The retardation film may have a refractive index (nx) in the in-plane slow axis direction, a refractive index (ny) in the in-plane fast axis direction, and a refractive index (nz) in the thickness direction that satisfy nx>nz>ny. The retardation film may have a change in the slow axis relative to the tension of 0.1°/N/10mm or more when tension is applied in a direction of 45° with respect to the slow axis direction.

The angle (θ ₀ ) formed between the absorption axis direction of the polarizer and the slow axis direction of the retardation film in the adhesive-coated polarizing plate before bonding to the image display cell, and the absorption axis direction of the polarizer after bonding the adhesive-coated polarizing plate to the image display cell. The absolute value (|θ ₁ -θ ₀ |) of the difference between the angle (θ ₁ ) formed by the slow axis direction of the retardation film is preferably 0.4° or less. In addition, the absolute value of the difference between the angle (θ ₂ ) formed by the absorption axis direction of the polarizer and the slow axis direction of the retardation film when the adhesive-coated polarizing plate is peeled from the image display cell and θ ₁ (|θ ₁ -θ ₂ | ) is preferably 0.4° or less. θ ₁ may be within the range of 0±0.4° or 90±0.4°.

Even when a retardation film of small thickness and high birefringence is used, an image display device with excellent display quality that is less prone to display unevenness can be obtained.

1 is a cross-sectional view of the structure of a liquid crystal display device.
Figure 2 is a cross-sectional view of the structure of an organic EL display device.
Figure 3 is a Cross-Nicol observation image of a sample in which a polarizing plate with an adhesive and a glass plate were bonded together. A is a sample in which stains were recognized, and B is a sample in which stains were not recognized.

The image display device of the present invention includes a polarizing plate bonded to the surface of an image display cell through an adhesive layer. The polarizing plate includes a polarizer and a retardation film disposed on one side of the polarizer, and the retardation film is disposed between the polarizer and the image display cell. Examples of image display devices in which a retardation film is disposed between a polarizer and an image display cell include a liquid crystal display device and an organic EL display device.

[Configuration of liquid crystal display device]

1 is a cross-sectional view of the structure of a liquid crystal display device according to one embodiment. The liquid crystal display device 201 includes a liquid crystal panel 100 and a light source 105. The liquid crystal panel 100 has a first polarizing plate 36 on the surface of the liquid crystal cell 10 on the viewing side, and a second polarizing plate 56 on the light source 105 side of the liquid crystal cell 10.

The liquid crystal cell 10 includes a liquid crystal layer 11 between two substrates 13 and 15. The substrates 13 and 15 are transparent substrates such as glass substrates or plastic substrates. In a typical configuration, a color filter and a black matrix are provided on one substrate, and a switching element that controls the electro-optical characteristics of the liquid crystal is provided on the other substrate. This is provided.

The liquid crystal layer 11 includes liquid crystal molecules aligned in a predetermined direction in an electroless state, and when a voltage is applied, the orientation direction (director) of the liquid crystal molecules changes. For example, in an in-plane switching (IPS) liquid crystal cell, the liquid crystal molecules of the liquid crystal layer 11 are oriented parallel and uniformly with respect to the substrate plane in an electric field-free state (homogeneous orientation), and die when a voltage is applied. The rector rotates within the plane of the substrate. The orientation direction of the liquid crystal molecules in the electroless state of the IPS liquid crystal cell may be slightly inclined with respect to the substrate plane. In an IPS type liquid crystal cell, the angle (pretilt angle) formed between the substrate plane and the orientation direction of the liquid crystal molecules in an electroless state is generally 10° or less.

A first polarizing plate 36 is bonded to the viewer side substrate 13 of the liquid crystal cell 10 via a first adhesive layer 39. A second polarizing plate 56 is bonded to the substrate 15 on the light source side of the liquid crystal cell 10 via a second adhesive layer 59.

Polarizers 36 and 56 include polarizers 31 and 51, respectively. The polarizers 31 and 51 absorb the vibrating light in the absorption axis direction and transmit (emitted) the vibrating light in the transmission axis direction as linearly polarized light. The polarizer 31 of the first polarizer 36 and the polarizer 51 of the second polarizer 56 are arranged so that their absorption axes are perpendicular to each other.

As a polarizer, dichroic substances such as iodine and dichroic dyes are adsorbed onto hydrophilic polymer films such as polyvinyl alcohol-based films, partially foamed polyvinyl alcohol-based films, and partially saponified ethylene-vinyl acetate copolymer-based films. Examples include polyene-based oriented films such as uniaxially stretched products, dehydrated products of polyvinyl alcohol, and dehydrochloric acid-treated products of polyvinyl chloride.

Among them, polyvinyl alcohol (PVA) is produced by adsorbing a dichroic material such as iodine or dichroic dye to a polyvinyl alcohol-based film such as polyvinyl alcohol or partially foamed polyvinyl alcohol and orienting it in a predetermined direction because it has a high degree of polarization. )-based polarizer is preferable. For example, a PVA-based polarizer can be obtained by performing iodine dyeing and stretching on a polyvinyl alcohol-based film.

As a PVA-based polarizer, a thin polarizer with a thickness of 10 μm or less can also be used. As a thin polarizer, for example, those described in Japanese Patent Application Laid-Open No. 51-069644, Japanese Patent Application Publication No. 2000-338329, pamphlet of WO2010/100917, specification of Japanese Patent No. 4691205, specification of Japanese Patent No. 4751481, etc. A thin polarizing film can be mentioned. Such a thin polarizer can be obtained, for example, by stretching a PVA-based resin layer and a resin substrate for stretching in the state of a laminate and dyeing with iodine.

In the first polarizing plate 36, transparent protective films 33 and 35 are bonded to both sides of the polarizer 31. In the second polarizing plate 56, transparent protective films 53 and 55 are bonded to both sides of the polarizer 51.

The thickness of the transparent protective films 33, 35, 53, and 55 is, for example, about 5 to 200 μm. As the resin material constituting these protective films, polymers excellent in transparency, mechanical strength, and thermal stability are preferably used. Specific examples of such polymers include cellulose resins such as acetylcellulose, polyester resins, polycarbonate resins, polyamide resins, polyimide resins, maleimide resins, polyolefin resins, (meth)acrylic resins, Cyclic polyolefin resin (norbornene-based resin), polyarylate-based resin, polystyrene-based resin, polyvinyl alcohol-based resin, polysulfone-based resin, and mixtures or copolymers thereof are included.

The polarizers 31 and 51 and the transparent protective films 33, 35, 53 and 55 are bonded together via an adhesive or pressure-sensitive adhesive (not shown). Adhesives and adhesives used to bond a polarizer to a transparent protective film include acrylic polymers, silicone polymers, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate/vinyl chloride copolymer, modified polyolefin, epoxy polymer, Fluorine-based polymers, rubber-based polymers, etc. can be appropriately selected and used as base polymers.

In FIG. 1, the first polarizer 36 and the second polarizer 56 are provided with transparent protective films on both sides of the polarizers 31 and 51, but the polarizer may be provided with a transparent protective film only on one side of the polarizer. . Additionally, two or more transparent protective films may be bonded together on one side of the polarizer.

The adhesives constituting the adhesive layers 39 and 59 include acrylic polymers, silicone polymers, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate/vinyl chloride copolymer, modified polyolefin, epoxy type, fluorine type, and natural rubber. , a rubber-based polymer such as synthetic rubber can be appropriately selected and used as the base polymer. In particular, an acrylic adhesive is preferably used because it has excellent optical transparency and exhibits adhesive properties such as appropriate wettability, cohesiveness, and adhesiveness. The thickness of the adhesive layers 39 and 59 is approximately 5 to 50 μm.

In the formation of a liquid crystal display device, a polarizer and a transparent protective film are bonded together in advance to form polarizers 36 and 56, and adhesive layers 39 and 59 are laid on the surfaces of the polarizers 36 and 56 to produce a polarizer with adhesive. do. This adhesive-coated polarizing plate and the liquid crystal cell 10 are bonded together using a bonding machine such as a roll laminator.

[Phase contrast film]

In the liquid crystal display device of one embodiment, the transparent protective film 35 of the first polarizing plate 36 is a retardation film. The retardation film 35 disposed between the polarizer 31 and the liquid crystal cell 10 can realize optical compensation such as improving contrast or expanding the viewing angle. For example, when an IPS liquid crystal display device is viewed from an oblique direction at an angle of 45 degrees (azimuth angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees) with respect to the absorption axis of the polarizer, the leakage of black display is large and the contrast is low. Deterioration or color shift is likely to occur. By disposing a retardation film with an in-plane retardation of 1/2 of the wavelength (λ) and an Nz coefficient of 0.5 between the liquid crystal cell and the polarizer, black luminance in the oblique direction can be reduced and contrast can be improved.

In addition, the Nz coefficient of the retardation film is defined as Nz = (nx-nz)/(nx-ny), with the refractive index in the slow axis direction in the plane being nx, the refractive index in the fast axis direction being ny, and the refractive index in the thickness direction being nz. do. The in-plane retardation (Re) of the retardation film is expressed as Re=(nx-ny)×d. d is the thickness of the retardation film.

In order to produce in-plane retardation of λ/2 for light with a wavelength of around 550 nm, which has high visibility, with a single sheet of thin retardation film with a small thickness (e.g., 35㎛ or less), the in-plane birefringence of the retardation film, Δn=(nx-ny) It is required to be 8×10 ^-3 or more. Such retardation films with small thickness and high birefringence are, for example, as described in Japanese Patent Application Laid-Open No. 2005-181451, Japanese Patent Application Publication No. 2011-227430, and Japanese Patent Application Publication No. 2016-109924. It can be formed by applying a resin solution on a support film, drying the solvent, and stretching a laminate of the support and the resin coating film. Handling can be improved by handling a retardation film with a small thickness as a laminated body with a support film. By using a heat-shrinkable film as a support film and shrinking the laminate in a direction perpendicular to the stretching direction during stretching, a retardation film having a refractive index anisotropy of nx>nz>ny can be obtained. Separately from the support film, a heat-shrinkable film may be bonded to provide shrinkage force in a specific direction.

The manufacturing method of the retardation film is not limited to the above, and various known methods can be adopted. Additionally, an appropriate refractive index anisotropy or retardation of the retardation film can be adopted depending on the type of liquid crystal cell, etc. The retardation film may be a positive A plate (nx>ny=nz), a negative B plate (nx>ny>nz), a negative A plate (nz=nx>ny), or a positive B plate (nz>nx>ny).

In the production of retardation films, positive A plates, and negative B plates having a refractive index anisotropy of nx>nz>ny, a polymer having positive intrinsic birefringence is preferably used. A polymer having positive intrinsic birefringence indicates that the refractive index in the orientation direction becomes relatively large when the polymer is oriented by stretching or the like. Polymers having positive intrinsic birefringence include, for example, polycarbonate-based resins, polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, polyarylate-based resins, sulfone-based resins such as polysulfone and polyethersulfone, and polyphenylene sulfide. Sulfide-based resins, polyimide-based resins, cyclic polyolefin-based (polynorbornene-based) resins, polyamide resins, polyolefin-based resins such as polyethylene and polypropylene, and cellulose esters. Additionally, a liquid crystal material may be used as a material having positive intrinsic birefringence.

A polymer having a negative intrinsic birefringence is preferably used in the production of negative A plate and positive B plate. A polymer having a negative intrinsic birefringence indicates that the refractive index in the orientation direction becomes relatively small when the polymer is oriented by stretching or the like. Polymers with negative intrinsic birefringence include, for example, those in which chemical bonds or functional groups with high polarization anisotropy, such as aromatic or carbonyl groups, are introduced into the side chains of the polymer, and specifically, acrylic resins, styrene-based resins, and maleimide-based resins. Resins, fumaric acid ester-based resins, etc. can be mentioned. Additionally, a liquid crystal material may be used as a material having negative intrinsic birefringence. For example, a negative A plate can be obtained from discotic liquid crystal aligned perpendicularly to the film plane.

When a polymer is used as a material for the retardation film, the retardation film can be formed by stretching the polymer film and increasing the molecular orientation in a specific direction. Stretching methods for polymer films include longitudinal uniaxial stretching, transverse uniaxial stretching, vertical and horizontal sequential biaxial stretching, and longitudinal and transverse simultaneous biaxial stretching. As the stretching means, any suitable stretching machine can be used, such as a roll stretching machine, tenter stretching machine, pantograph type, or linear motor type biaxial stretching machine. As described above, refractive index anisotropy can also be controlled by using the shrinkage force of the heat shrinkable film during stretching. The laminate in which the liquid crystal layer is formed on the substrate may be used as a retardation film or may be transferred to another film.

As described above, in order to realize large in-plane retardation (for example, 200 nm or more) with a small thickness, the in-plane birefringence of the retardation film, Δn=(nx-ny), is preferably 8×10 ^-3 or more. The in-plane birefringence (Δn) of the retardation film may be 1.0×10 ^-2 or more, 1.2×10 ^-2 or more, or 1.3×10 ^-2 or more.

From the viewpoint of thinning, the thickness of the retardation film is preferably 35 μm or less. The thickness of the retardation film may be 30 μm or less, 25 μm or less, or 20 μm or less. The thickness of the retardation film is generally 1 μm or more, and may be 3 μm or more, 5 μm or more, or 7 μm or more. As described above, by stretching the resin coating integrally with the film substrate, a retardation film with a small thickness can be produced without compromising handling properties.

[Polarizer with adhesive]

A polarizing plate can be obtained by bonding a retardation film as a transparent protective film 35 on one side of the polarizer 31. An optically isotropic film may be bonded on the polarizer 31 as a transparent protective film 35, and a retardation film may be bonded to the transparent protective film 35 through an appropriate adhesive or pressure-sensitive adhesive. A transparent protective film 33 is bonded to the other side of the polarizer 31. The transparent protective film 33 may be omitted. When the transparent protective film 33 is omitted, the polarizing plate 36 is provided with the transparent protective film 35 only on one side of the polarizer.

In a polarizing plate used in an IPS type liquid crystal display device, the absorption axis direction of the polarizer and the slow axis direction of the retardation film are bonded so that they are parallel or perpendicular to each other. In order to increase the precision of the optical axis, it is preferable to bond the polarizer and the retardation film using a roll-to-roll method. A polarizer generally has an absorption axis in the long direction (stretching direction). Therefore, when the absorption axis direction of the polarizer and the slow axis direction of the retardation film are parallel, it is preferable to use a retardation film having a slow axis in the longitudinal direction, and when the absorption axis direction of the polarizer and the slow axis direction of the retardation film are orthogonal. It is preferable to use a retardation film having a slow axis in the width direction.

By bonding the adhesive layer 39 to the surface of the retardation film 35, a polarizing plate with an adhesive in which the adhesive layer 39 is attached to the surface of the polarizing plate 36 can be obtained. It is preferable that the adhesive layer is bonded using a roll-to-roll method.

Before bonding the polarizing plate to the image display cell, it is preferable to temporarily attach a release film (separator) to the exposed surface of the adhesive layer 39 attached to the surface of the polarizing plate. As a release film, for example, a plastic film whose surface has been subjected to a peeling treatment is used.

[Layering of polarizer with adhesive onto image display cell]

A liquid crystal panel is formed by bonding a polarizing plate with adhesive having a retardation film 35 between the polarizer 31 and the adhesive layer 39 to the substrate 13 of the liquid crystal cell 10. A polarizing plate with an adhesive, in which an adhesive layer 59 is attached to the surface of the polarizing plate 56, is bonded to the substrate 15 on the light source side of the liquid crystal cell. The front and back polarizing plates 36 and 56 may be bonded to the liquid crystal cell 10 simultaneously or sequentially.

In bonding using an adhesive layer, pressurization is performed from the viewpoint of increasing adhesion at the bonding interface and preventing mixing of air bubbles and peeling. Pressure bonding methods include roller type and drum type.

As shown in the examples described later, the direction of the optical axis of the highly birefringent retardation film is likely to change due to tension (stress). The change in the optical axis direction of the retardation film due to tension is performed by cutting the retardation film into a strip shape with a width of 10 mm at an angle of 45° with respect to the slow axis direction and applying tension to the long side of the strip-shaped sample in the slow axis direction. It can be obtained by measuring . The tension is plotted on the horizontal axis and the angle (change in) of the slow axis is plotted on the vertical axis, and the slope of the straight line obtained by the least squares method is the change in slow axis with respect to tension (unit: °/N/10mm).

For retardation films with an in-plane birefringence of 8×10 ^-3 or more, the amount of change in the slow axis with respect to tension may be 0.1°/N/10 mm or more. The smaller the thickness and the larger the in-plane birefringence of the retardation film, the larger the change in the slow axis with respect to tension, and the change in the optical axis with respect to tension may be 0.2°/N/10mm or more or 0.3°/N/10mm or more.

In this way, when a polarizing plate including a retardation film whose direction of the optical axis is easily changed is bonded to an image display cell, a deviation occurs in the bonding angle of the polarizer and the retardation film, which may be recognized as an optical stain in the displayed image.

The amount of change (deviation) in the angle between the absorption axis direction of the polarizer 31 and the optical axis (slow axis or fast axis) direction of the retardation film 35 is preferably 0.4° or less, and more preferably 0.3° or less. The amount of change in the axis angle is the angle (θ) formed between the absorption axis direction of the polarizer 31 and the slow axis direction of the retardation film 35 when the polarizer 36 is bonded to the image display cell through the adhesive layer 39. ₁ ) and the difference between the angle (θ ₀ ) before bonding. The change in axis angle may be 0.2° or less or 0.1° or less. When the amount of deviation of the axis angle is 0.4° or less, the occurrence of optical stains can be suppressed even when the birefringence of the retardation film 35 is large. The smaller the amount of misalignment, the more likely it is that the occurrence of stains will be suppressed.

In a state in which a polarizing plate is bonded to an image display cell through an adhesive layer, the angle formed between the absorption axis direction of the polarizer and the optical axis direction of the retardation film is preferably 0.4° or less, more preferably 0.3° or less, and 0.2° or less. is more preferable. When the absorption axis direction of the polarizer and the slow axis direction of the retardation film are parallel, θ ₁ is preferably within the range of 0±0.4°, more preferably within the range of 0±0.3°, and within the range of 0±0.2°. It is more desirable. When the absorption axis direction of the polarizer and the slow axis direction of the retardation film are orthogonal, θ ₁ is preferably within the range of 90 ± 0.4°, more preferably within the range of 90 ± 0.3°, and within the range of 90 ± 0.2°. It is more desirable.

The larger the thickness of the adhesive layer 39 used to bond the polarizer 36 (retardation film 35) and the image display cell 10 and the softer the adhesive, the greater the axial angle between the polarizer 31 and the retardation film 35. The amount of misalignment tends to increase. The shear storage modulus (G') at room temperature (25°C) can be used as an indicator of the hardness of the adhesive. The larger G', the harder the adhesive is, and the smaller G' is, the softer it is.

The larger the shear storage modulus (G') of the adhesive layer 39 divided by the thickness (D) (G'/D) at a temperature of 25°C (the harder and thinner the adhesive layer), the greater the polarizing plate through the adhesive layer. The amount of deviation of the axis angle when bonded to the image display cell tends to decrease. G'/D of the adhesive layer 39 is preferably 5.0 kPa/μm or more, and more preferably 5.2 kPa/μm or more. When G'/D is excessively large, the adhesion holding power decreases, and bonding defects such as mixing of air bubbles into the bonding interface may occur. Therefore, the G'/D of the adhesive layer 39 is preferably 28 kPa/μm or less, and more preferably 25 kPa/μm or less.

The thickness D of the adhesive layer 39 is preferably 5 to 25 μm, and more preferably 7 to 20 μm. The shear storage modulus (G') of the adhesive layer 39 at 25°C is preferably 50 kPa or more, more preferably 60 to 250 kPa, and still more preferably 70 to 200 kPa.

In addition to the physical properties of the adhesive used to bond the polarizer and the image display cell, the bonding pressure (lamination pressure) when bonding the adhesive-coated polarizer to the image display cell also affects the misalignment of the axial angles of the polarizer and the retardation film. There is a tendency that the higher the lamination pressure, the greater the amount of deviation of the axial angles of the polarizer and the retardation film. When a polarizing plate including a retardation film with large birefringence and a large change in the optical axis with respect to tension is bonded to an image display cell, the lamination pressure is preferably 0.4 MPa or less, and more preferably 0.3 MPa or less. On the other hand, if the lamination pressure is excessively low, bonding defects such as mixing of air bubbles into the bonding interface may occur. Therefore, the lamination pressure is preferably 0.05 MPa or more, and more preferably 0.1 MPa or more.

As described above, when the birefringence of the retardation film is large, a change (misalignment) in the axis angle due to bonding is likely to occur, which may cause optical unevenness in the displayed image. However, the thickness and hardness of the adhesive layer, and/or By adjusting the laminate pressure during bonding, the occurrence of stains can be suppressed.

The physical properties and lamination pressure of the adhesive layer 59 when bonding the polarizing plate 56 on the other side to the liquid crystal cell 10 are not particularly limited. The thickness and shear storage modulus of the adhesive layer 59 may be the same as or different from those of the adhesive layer 39. The laminating pressure when bonding the polarizing plate 56 together may be equal to or different from the laminating pressure when bonding the polarizing plate 36 together.

<Estimated mechanism of stain generation and reduction>

As described above, in an image display device in which display unevenness occurs, the amount of change (|θ ₁ -θ ₀ |) in the angle formed by the absorption axis direction of the polarizer and the slow axis direction of the retardation film before and after bonding is large. When a polarizing plate is peeled (reworked) from an image display device in which display unevenness occurs and the angle (θ ₂ ) formed between the absorption axis direction of the polarizer and the slow axis direction of the retardation film is measured, the value becomes almost the same as before bonding. That is, the angle (θ ₀ ) formed between the absorption axis direction of the polarizer before bonding the polarizer to the image display cell and the slow axis direction of the retardation film, and the absorption axis of the polarizer after bonding and reworking the adhesive-coated polarizer with the image display cell. The angle (θ ₂ ) formed by the direction and the slow axis direction of the retardation film is almost equal. Additionally, when the reworked polarizing plate is relaminated to the image display cell at low laminating pressure, the change in axial angle is small and no staining occurs.

Therefore, the change in axis angle when a polarizing plate is bonded to an image display cell can be said to be a reversible change. Display unevenness resulting from such a reversible change in axis angle is thought to be caused by residual strain caused by pressure when polarizing plates are bonded together. For example, when bonding is performed at a high lamination pressure, the adhesive layer, which has a lower elastic modulus than the film, is deformed and elastic strain occurs. When bonding using a roll laminator or drum laminator, pressure is applied from directions other than the direction normal to the bonding surfaces, so it is believed that strain due to pressure from various directions is accumulated in the adhesive layer.

When the pressure is released after bonding, the adhesive layer tries to return to its original shape. However, since the adhesive layer is bonded to the substrate of the image display cell, the degree of freedom of deformation is reduced compared to before bonding. Therefore, the adhesive layer cannot completely return to its original shape, and some of the strain caused by pressure applied from various directions during bonding remains inside the adhesive layer. It is thought that this strain causes strain at the bonding interface between the retardation film bonded to the adhesive layer and becomes a factor that changes the optical axis of the retardation film.

If the laminating pressure during bonding is lowered, the strain accumulated in the adhesive layer 39 is small, so the strain remaining in the adhesive layer after bonding is also small, and the strain at the bonding interface with the retardation film also becomes small. In addition, when the thickness (D) of the adhesive layer 39 is small and the shear storage modulus (G') is large, the amount of deformation of the adhesive layer due to pressure is small, so the strain remaining in the adhesive layer 39 is small and the retardation film and The strain at the bonding interface also decreases. Therefore, when bonding is performed at a low laminating pressure using a small-thick, hard adhesive, it is difficult for the strain that changes the optical axis direction of the retardation film to accumulate, and the amount of change in the optical axis (|θ ₁ -θ ₀ |) is small. It is assumed that the occurrence of stains is suppressed.

[Other optical members]

A liquid crystal display device is formed by combining a liquid crystal panel 100 in which polarizers 36 and 56 are bonded to both sides of a liquid crystal cell 10 and a light source 105. The liquid crystal display device may include optical layers or other members other than those described above. For example, a brightness enhancing film (not shown) may be provided between the liquid crystal panel 100 and the light source 105. The brightness improving film may be laminated with the polarizing plate 56 on the light source side.

The transparent protective film 33 on the viewing side may be provided with a hard coat layer for the purpose of providing scratch resistance or the like. Additionally, the transparent protective film 33 may be provided with an anti-reflection layer. A touch panel sensor, a cover window, etc. may be disposed further on the viewer's side of the polarizing plate 36 on the viewer's side.

In the above example, an example has been described where the polarizing plate 36 disposed on the viewer side of the liquid crystal cell 10 includes the highly birefringent retardation film 35, but on the liquid crystal cell side of the polarizing plate 56 on the light source side. The disposed film 55 may be a highly birefringent retardation film. In this case, the occurrence of unevenness can be suppressed by using a high G'/D as the adhesive layer 59 for bonding the polarizing plate 56 and the liquid crystal cell 10 and/or reducing the lamination pressure during bonding. there is.

The absorption axis direction of the polarizer and the slow axis direction of the retardation film may be arranged at an angle that is neither parallel nor perpendicular. Even when the polarizer and the retardation film are laminated at an angle where the optical axes of both are neither parallel nor perpendicular, an adhesive layer with a large G'/D is used as an adhesive layer for bonding the polarizer and the image display cell, and/or a laminate at the time of bonding. By reducing the pressure, the amount of deviation of the optical axis before and after bonding is small, and the occurrence of unevenness can be suppressed.

[Organic EL display device]

As an image display device provided with a polarizing plate in which a polarizer and a retardation film are laminated at an angle in which the optical axis is neither parallel nor perpendicular, examples of the image display device include, in addition to a liquid crystal display device, an organic EL display device. The organic EL display device 202 shown in FIG. 2 is provided with a bottom emission type organic EL cell 70 in which a transparent electrode 72, an organic light emitting layer 71, and a metal electrode 74 are provided in that order on a transparent substrate 73. do.

As the transparent substrate 73, a glass substrate or a plastic substrate is used. The organic EL light emitting layer 71 may include an electron transport layer, a hole transport layer, etc. in addition to the organic layer that itself functions as a light emitting layer. The transparent electrode 72 is a metal oxide layer or a metal thin film, and transmits light from the organic light-emitting layer 71. Accordingly, light (image light) from the organic light-emitting layer 71 passes through the transparent electrode 72 and the substrate 73 and is taken out toward the viewer.

Metal electrode 74 is light reflective. Therefore, when external light enters the inside of the organic EL cell from the substrate 73, the light is reflected by the metal electrode 74, and the reflected light is recognized as a mirror surface from the outside. From the viewpoint of preventing re-emission of light reflected from the metal electrode 74 to the outside and improving the visibility and design of the display device, an adhesive layer 39 is provided on the viewing side surface of the organic EL cell 70. A circularly polarizing plate 37 is bonded together.

The circularly polarizing plate 37 has a configuration in which transparent protective films 33 and 34 are laminated on both sides of the polarizer 31, and the transparent protective film 34 is disposed between the polarizer 31 and the organic EL cell 70. is a retardation film. When the retardation film 34 has a retardation of λ/4 and the angle between the slow axis direction of the retardation film 34 and the absorption axis direction of the polarizer 31 is 45°, lamination of the polarizer and the retardation film The body (polarizing plate 37) functions as a circularly polarizing plate. Except that the retardation film 34 is a quarter wave plate and the angle between the optical axes of the retardation film 34 and the polarizer 31 is 45°, the configuration of the polarizer 37 is the same as that of the polarizer 36 described above. am.

Additionally, the retardation film constituting the circularly polarizing plate may be a lamination of two or more layers of films. For example, by stacking a polarizer, a λ/2 plate, and a λ/4 plate so that each optical axis forms a predetermined angle, a broadband circularly polarizing plate that functions as a circularly polarizing plate over a wide band of visible light can be obtained.

The circularly polarizing plate 37 can be obtained by bonding the polarizer 31 and the retardation film 34 through an appropriate adhesive or pressure-sensitive adhesive. An optical isotropic film may be bonded on the polarizer 31 and a retardation film may be bonded thereon. A transparent protective film 33 may be bonded to the other side of the polarizer 31.

An organic EL display device is formed by bonding a pressure-sensitive adhesive polarizer having a retardation film 34 between the polarizer 31 and the pressure-sensitive adhesive layer 39 to the substrate 73 of the organic EL cell 70. Similar to the above-described embodiment of the liquid crystal display device, a retardation film ( 34) Even with high birefringence, the occurrence of unevenness can be suppressed by setting the change in axial angle (|θ ₁ -θ ₂ |) before and after bonding to 0.4° or less.

Although the example of the bottom emission type organic EL cell 70 has been described above, the organic EL cell may be of the top emission type. A top emission type organic EL cell generally includes a metal electrode, an organic light-emitting layer, and a transparent electrode in that order on a substrate. An encapsulation substrate is provided on the transparent electrode layer, and a circularly polarizing plate is bonded on the encapsulation substrate. The organic EL display device may be provided with a touch panel sensor, a cover window, etc. on the more visible side of the circularly polarizing plate 37.

[Example]

The present invention will be described in more detail below by way of examples, but the present invention is not limited to the following examples.

[Adhesive sheet]

<Preparation of adhesive composition>

(Adhesive composition P)

In a reaction vessel, butyl acrylate (BA) as a monomer: 99 parts by weight, 4-hydroxybutyl acrylate (4HBA): 1 part by weight, and 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator: 0.3 parts, It was added together with ethyl acetate and reacted at 60°C under a nitrogen gas stream for 4 hours. After that, ethyl acetate was added to the reaction solution to obtain an acrylic polymer solution with a weight average molecular weight of 1.65 million. In this solution, based on 100 parts by weight of polymer, as a crosslinking agent, dibenzoyl peroxide ('Nipa BMT', manufactured by Nippon Oil and Oil): 0.3 parts by weight and trimethylolpropanexylylene diisocyanate ('Takenato D110N', manufactured by Mitsui Chemicals): Adhesive composition A was obtained by mixing 0.1 parts by weight and a silane coupling agent ('A-100' manufactured by Soken Chemical).

(Adhesive composition Q)

BA: 94.9 parts by weight, acrylic acid (AA): 5 parts by weight, 2-hydroxyethyl acrylate (2HEA): 0.1 parts by weight, and AIBN: 0.1 parts by weight as a polymerization initiator were added to the reaction vessel along with ethyl acetate, and nitrogen was added to the reaction vessel. The reaction was carried out at 55°C under a gas stream for 8 hours. Afterwards, ethyl acetate was added to the reaction solution to obtain an acrylic polymer solution with a weight average molecular weight of 2.1 million. To this solution, based on 100 parts by weight of polymer, trimethylolpropane/tolylene diisocyanate adduct (Tosoh's 'Coronato L'): 0.6 parts by weight as a crosslinking agent, and a silane coupling agent (Shin-Etsu Chemical Co.'s 'X-41-1056') ') 0.2 parts by weight was mixed to obtain adhesive composition B.

(Adhesive composition R)

In a reaction vessel, BA: 92 parts by weight, N-acryloylmorpholine (ACMO): 5 parts by weight, AA: 2.9 parts by weight, and 2HEA: 0.1 parts by weight and AIBN: 0.1 parts by weight as a polymerization initiator were added together with ethyl acetate. , reaction was performed at 55°C under a nitrogen gas stream for 8 hours. Afterwards, ethyl acetate was added to the reaction solution to obtain an acrylic polymer solution with a weight average molecular weight of 1.78 million. To this solution, Naipa BMT: 0.15 parts by weight and Coronato L: 0.6 parts by weight as crosslinking agents were mixed with 100 parts by weight of polymer to obtain adhesive composition C.

<Production of adhesive sheet>

The above adhesive compositions A to C were applied to the release-treated surface of a polyethylene terephthalate film ('MRF38' manufactured by Mitsubishi Chemical) with a thickness of 38 ㎛, and dried and cross-linked at 150°C to obtain a thickness of 5 ㎛. Adhesive sheets of 10㎛, 15㎛, 20㎛, and 25㎛ were produced. The adhesive sheets produced using adhesive composition P are adhesive sheets P1 to P5, the adhesive sheets produced using adhesive composition Q are adhesive sheets Q1 to Q5, and the adhesive sheets produced using adhesive composition R are adhesive sheets R1 to R5. Do this.

[Experimental Example A1]

<Production of phase contrast film A>

In a reaction vessel equipped with a stirring device, 2,2-bis(4-hydroxyphenyl)-4-methylpentane: 54 parts by weight and benzyltriethylammonium chloride: 12 parts by weight were dissolved in 1 M sodium hydroxide solution. While stirring this solution, a solution of 406 parts by weight of terephthalic acid chloride dissolved in chloroform was added at a time and stirred at room temperature for 90 minutes. Thereafter, the polymerization solution was left standing to separate the chloroform solution containing the polymer, which was then washed with acetic acid water and ion-exchanged water, and then poured into methanol to precipitate the polymer. The precipitated polymer was washed twice with distilled water and twice with methanol, and then dried under reduced pressure to obtain a polyarylate resin. The obtained polyarylate-based resin was dissolved in cyclopentanone to prepare a solution with a solid content concentration of 20%.

Using a biaxially stretched polypropylene film as a support, the above solution was applied so that the dried film thickness was 15 μm, and dried at 100°C to obtain a laminate in which a polyarylate resin layer was laminated on the support film. This laminate was contracted in the width direction while being stretched in the conveyance direction using a roll stretching machine. The stretched polyarylate coating film (retardation film A) after peeling off the support film had a thickness of 17 μm, an in-plane retardation of 250 nm at a wavelength of 550 nm, and an Nz coefficient of 0.5.

<Production of polarizer>

A biaxially stretched acrylic film with a thickness of 40 μm was bonded to one side of a polyvinyl alcohol-based polarizer with a thickness of 18 μm, and the side of the retardation film A of the above laminate was bonded to the other side through an ultraviolet curing adhesive. A roll laminator was used for bonding, and the adhesive was cured by irradiating ultraviolet rays. After that, the polypropylene film used as the support film is peeled off, and the adhesive sheet prepared above is laminated on the retardation film A side, so that one side of the polarizer is provided with an acrylic film and the other side is provided with retardation film A, and the retardation film A side is provided. A polarizing plate with an adhesive having an adhesive layer on its surface was obtained.

<Combination to glass plate>

The above-mentioned polarizing plate with adhesive was placed on an alkali-free glass plate with a thickness of 0.7 μm, and was bonded using a pressure roller type sheet bonding device at a lamination pressure of 0.3 MPa to obtain a sample for evaluation.

[Experimental Example B1]

Instead of retardation film A, a norbornene-based resin film (retardation film B) with a thickness of 132 μm, an in-plane retardation of 250 nm, and an Nz coefficient of 0.5 was used, and a polarizing plate with an adhesive was produced and bonded to a glass plate in the same manner as above.

[Experimental Example C1]

Instead of retardation film A, a biaxially stretched norbornene-based resin film (retardation film C) with a thickness of 18 μm, an in-plane retardation of 120 nm, and an Nz coefficient of 1.18 was used to produce a polarizing plate with an adhesive and bond it to a glass plate in the same manner as above. did.

[evaluation]

<Shear storage modulus of adhesive sheet>

For each of the adhesive sheets P3, Q3, and R3, 100 adhesive sheets were laminated to produce a sample for testing. This sample was punched into a disk shape with a diameter of 7.9 mm, inserted into a parallel plate, and dynamic viscoelasticity was measured according to the following conditions using the 'Advanced Rheometric Expansion System (ARES)' manufactured by Rheometric Scientific. and the shear storage modulus at 25°C was read.

(Measuring conditions)

Deformation Mode: Torsion

Measurement frequency: 1Hz

Temperature increase rate: 5℃/min

Measurement temperature: -40∼150℃

<Change of slow axis angle in response to tension of retardation film>

The retardation film was cut into a strip shape with a width of 10 mm so that the long side was at an angle of 45° with respect to the slow axis direction. On the measurement stage of a polarization/phase contrast measurement system (AxoScan manufactured by Axometrics), one short side of a strip-shaped sample is fixed, a weight is hung on the other short side, and tension is applied in the longitudinal direction of the sample, and in-plane retardation is performed. Dation and slow axis direction were measured. By changing the mass of the weight, the change in the slow axis angle with respect to the tension (based on the slow axis angle when the tension is 0) was plotted, and the change in the axis angle with respect to the tension (change in axis/tension) was calculated from the slope of the straight line.

<Change in optical axis of polarizer>

The angle (θ ₀ ) formed between the absorption axis direction of the polarizer in the adhesive-coated optical film and the slow axis direction of the retardation film was measured using a polarization/phase difference measurement system. For a sample after bonding an optical film with an adhesive on a glass plate, the angle (θ ₁ ) formed between the absorption axis direction of the polarizer and the slow axis direction of the retardation film was measured, and the angle difference (θ ₁ -θ ₀ ) before and after bonding was measured. The absolute value was obtained.

<State of bonding>

The presence or absence of bubbles at the bonding interface between the glass plate and the polarizing plate was observed with the naked eye.

<Optical stain>

A standard polarizing plate (manufactured by Nitto Denko) in which an acrylic film was bonded as a transparent protective film to both sides of a polyvinyl alcohol-based polarizer was placed on the trace table, and the glass plate of the evaluation sample was placed on it so that the glass plate of the evaluation sample was on the lower side. The two polarizing plates were arranged so that the absorption axis direction of the standard polarizing plate and the absorption axis direction of the polarizing plate of the evaluation sample were perpendicular (Cross-Nicol arrangement). Transmitted light from the trace was visually confirmed, and stains were ranked according to the following criteria.

　　○: No stains were recognized (see Fig. 3A)

　　△: Minor stains confirmed

　　×: Significant staining was confirmed (see Figure 3B)

<Evaluation results>

Table 1 shows the thickness and optical properties of retardation films A to C, the thickness (D) of the adhesive sheet, the shear storage modulus (G') at 25°C, and the evaluation results of the bonded samples.

[Table 1]

It can be seen that the change in the slow axis direction with respect to tension for both retardation films B and C was 0.01°/N/10mm, while retardation film A, which has a large birefringence, has a large change rate in the slow axis direction with respect to tension.

In the polarizing plate in which the polarizer is laminated on the retardation film A, the slow axis direction of the retardation film and the absorption axis direction of the polarizer are parallel (θ ₀ is 0.1° or less) before bonding to the glass plate, but after bonding the polarizing plate with adhesive to the glass plate, Axial misalignment occurred, and it was seen that the larger the thickness (D) of the adhesive sheet and the smaller the shear storage modulus (G'), the larger the axial misalignment. No stains were observed in the sample using the adhesive sheet R1, but inclusion of air bubbles was seen at the bonded interface between the glass plate and the adhesive layer.

Even when the polarizer, which is a laminate of retardation film B and a polarizer, is bonded to a glass plate through adhesive sheets P4, P5, and Q5 with large thickness and low shear storage modulus (G'), no clear axis deviation is observed and no staining occurs. didn't The same was true when using retardation film C.

[Experimental Example A2]

A polarizing plate with an adhesive was used, which included an acrylic film on one side of the polarizer, retardation film A on the other side, and a 15-μm-thick adhesive sheet P3 laminated on the side of the retardation film A. As shown in Table 2, a polarizing plate with an adhesive was bonded to an alkali-free glass plate in the same manner as in Experimental Example A1 except that the lamination pressure was changed to the range of 0.01 to 1.0 MPa to obtain a sample for evaluation.

[Experimental Example B2]

A polarizing plate with an adhesive in which the adhesive sheet P3 was laminated on the side of the retardation film B was used, and bonding to a glass plate was performed in the same manner as in Experimental Example B1 except that the laminating pressure was changed to 0.7 Pa or 1.0 MPa.

[Experimental Example C2]

A polarizing plate with an adhesive in which the adhesive sheet P3 was laminated on the side of the retardation film C was used, and bonding to a glass plate was performed in the same manner as in Experiment C1 except that the laminating pressure was changed to 0.7 Pa or 1.0 MPa.

[evaluation]

For each sample of Experimental Examples A2, B2, and C2, the amount of change in the optical axis, bonding state, and optical unevenness were evaluated. Table 2 shows the thickness and optical properties of retardation films A to C, bonding conditions (lamination pressure) and evaluation results of the adhesive-coated polarizing plate to the glass plate.

[Table 2]

It was observed that in the adhesive-coated polarizing plate in which retardation film A and the polarizer were laminated, the axis deviation tended to increase as the lamination pressure during bonding to the glass plate increased. When bonding was performed at a laminating pressure of 0.5 MPa, unevenness was confirmed in an optical unevenness test, and when the laminating pressure was further increased, the unevenness became more noticeable. No stains were observed in the sample bonded at a lamination pressure of 0.01 MPa, but inclusion of air bubbles was observed at the bonded interface between the glass plate and the adhesive layer.

In the adhesive-coated polarizing plate in which retardation film B and the polarizer were laminated, no clear axis deviation was observed and no staining occurred even when the laminating pressure at the time of bonding to the glass plate was increased to 1.0 MPa. The same was true when using retardation film C.

As described above, in a sample in which a polarizer obtained by laminating a polarizer and a retardation film A is bonded to a glass plate, the thickness (D) of the adhesive sheet is large and the shear storage modulus (G') is small (i.e., the adhesive sheet is thick and soft). , and when the lamination pressure during bonding was large, the deviation of the optical axis of the retardation film increased and optical unevenness occurred. On the other hand, in the polarizing plate in which a polarizer and retardation film B or retardation film C were laminated, optical staining was not observed even if the type of adhesive sheet or the lamination pressure was changed.

From these results, optical unevenness when a polarizing plate provided with a retardation film is bonded to a glass plate (substrate of an image display cell) is a problem unique to a retardation film with large birefringence, and is due to deformation of the adhesive sheet during bonding. It can be seen that the cause is the axis deviation of the retardation film. When a thin and hard adhesive is used or when the pressure during bonding is low, the deformation of the adhesive sheet is small, so it is thought that the axial deviation of the retardation film is suppressed.

For the samples in which significant unevenness was observed in Experimental Example A2 (a sample with a lamination pressure of 0.7 MPa and a sample with a 1.0 MPa pressure), the polarizing plate with an adhesive was peeled (reworked) from the glass plate, and the slow axis direction of the retardation film and the absorption axis direction of the polarizer were separated. When the angle difference θ ₂ was measured, it was within 0.1° and the axis deviation was eliminated. Additionally, the reworked polarizing plate with adhesive was bonded to the glass plate again at a laminating pressure of 0.3 MPa to check the presence or absence of optical stains, and no stains were confirmed.

From the above results, the optical staining of the sample in which the polarizing plate containing the retardation film A and the polarizer was bonded to the glass plate at a high lamination pressure is due to the residual strain when the adhesive sheet was deformed by the pressure during bonding, It is believed that the occurrence of stains can be suppressed by reducing the strain by reducing the pressure at the time of bonding. In addition, even when a pressure-sensitive adhesive sheet with a small thickness and low shear storage modulus is used, the strain caused by deformation of the pressure-sensitive adhesive sheet is small, so it is thought that axial displacement is unlikely to occur and the occurrence of stains can be suppressed.

10: liquid crystal cell
70: Organic EL cell
11: Liquid crystal layer
71: Organic light-emitting layer
72: transparent electrode
74: metal electrode
13, 15, 73: substrate
36, 37, 56: Polarizer
33, 51, 53: Transparent protective film
34, 35: Transparent protective film (phase contrast film)
39, 59: Adhesive layer
100: liquid crystal panel
105: light source
201: liquid crystal display device
202: Organic EL display device

Claims (15)

An image display device comprising an image display cell and a polarizing plate bonded to the surface of the image display cell through an adhesive layer,
The polarizing plate includes a polarizer and a retardation film disposed on one side of the polarizer,
The retardation film is disposed between the polarizer and the image display cell,
The retardation film has an in-plane birefringence of 8×10 ^-3 or more at a wavelength of 550 nm,
An angle (θ ₁ ) formed between the slow axis direction of the retardation film and the absorption axis direction of the polarizer in a state in which the polarizing plate is bonded to the image display cell via the adhesive layer, and the polarizing plate is used to display the image. An image display device in which the absolute value (|θ 1 -θ ₂ |) of the difference between the slow axis direction of the retardation film and the absorption axis direction of the polarizer when peeled from the cell (|θ ₁ -θ ₂ |) is 0.4° or less. . According to paragraph 1,
The retardation film is an image display device in which the change in the slow axis with respect to the tension when tension is applied in a direction of 45° with respect to the slow axis direction is 0.1°/N/10mm or more. According to claim 1 or 2,
The retardation film is an image display device in which the refractive index (nx) in the in-plane slow axis direction, the refractive index (ny) in the in-plane fast axis direction, and the refractive index (nz) in the thickness direction satisfy nx>nz>ny. According to claim 1 or 2,
An image display device wherein the θ ₁ is within the range of 0±0.4° or 90±0.4°. According to claim 1 or 2,
An image display device wherein the in-plane retardation of the retardation film is 200 nm or more. According to claim 1 or 2,
An image display device wherein the retardation film is in contact with the adhesive layer. According to claim 1 or 2,
An image display device wherein the shear storage modulus (G') of the adhesive layer divided by the thickness (D) (G'/D) at a temperature of 25°C is 5.0 kPa/μm or more. According to claim 1 or 2,
An image display device wherein the adhesive layer has a thickness of 25 μm or less. A method of manufacturing an image display device in which a polarizer and a polarizing plate including a retardation film disposed on the surface of the polarizer are bonded to the surface of an image display cell through an adhesive layer, comprising:
A retardation film having an in-plane birefringence of 8×10 ^-3 or more at a wavelength of 550 nm is laminated on one side of the polarizer, and an adhesive-attached polarizer is prepared with an adhesive layer laid on the retardation film,
A method for manufacturing an image display device, wherein the polarizing plate with adhesive and the image display cell are bonded together at a laminating pressure of 0.05 to 0.4 MPa. According to clause 9,
A method of manufacturing an image display device, wherein the shear storage modulus (G') of the adhesive layer divided by the thickness (D) (G'/D) at a temperature of 25°C is 5 kPa/μm or more. According to claim 9 or 10,
A method of manufacturing an image display device, wherein the adhesive layer has a thickness of 25 μm or less. According to claim 9 or 10,
In the pressure-sensitive adhesive polarizing plate, an angle (θ ₀ ) formed between the absorption axis direction of the polarizer and the slow axis direction of the retardation film, and the slow axis direction of the retardation film after bonding the pressure-sensitive adhesive polarizing plate to the image display cell, and A method of manufacturing an image display device, wherein the absolute value (|θ ₁ -θ ₀ |) of the difference from the angle (θ ₁ ) formed by the absorption axis direction of the polarizer is 0.4° or less. According to claim 9 or 10,
A method of manufacturing an image display device, wherein the in-plane retardation of the retardation film is 200 nm or more. According to claim 9 or 10,
A method of manufacturing an image display device, wherein the retardation film has a change in the slow axis with respect to the tension of 0.1°/N/10 mm or more when tension is applied in a direction of 45° with respect to the slow axis direction. According to claim 9 or 10,
The retardation film has a refractive index (nx) in the slow axis direction in the plane, a refractive index (ny) in the fast axis direction in the plane, and a refractive index (nz) in the thickness direction that satisfy nx>nz>ny. Manufacture of an image display device. method.