KR20220093160A - Polarizing plate, set of polarizing plate and image display device - Google Patents

Abstract

There is provided a polarizing plate in which a through hole is formed in the vicinity of an end, in which cracks around the through hole are significantly suppressed. The polarizing plate of this invention has a polarizer, the protective layer arrange|positioned at at least one side of a polarizer, and an adhesive layer. The polarizing plate has a rectangular shape, and a through hole is formed therein. The thickness of the polarizer is 10 µm to 20 µm. The polarizing plate in the through-hole portion after being subjected to a heat shock test in which 100 cycles of holding at -40 ° C. for 30 minutes and then maintaining at 85 ° C. for 30 minutes in a state bonded to a glass plate through an adhesive layer The amount of deviation is larger than 160 μm. The diameter of the through hole is 3 mm to 5 mm, and the through hole is formed within 11 mm from the long side, within 3 mm from the short side, within 3 mm from the long side, within 11 mm from the short side, or within 7 mm from the long side and within 5 mm from the short side.

Description

Polarizing plate, set of polarizing plate and image display device

The present invention relates to a polarizing plate, a set of polarizing plates, and an image display device.

A polarizing plate is widely used in image display apparatuses, such as a mobile phone and a notebook personal computer, in order to implement|achieve image display and/or to raise the performance of the said image display. DESCRIPTION OF RELATED ART In recent years, with the rapid spread of smart phone and touch panel type information processing apparatus, the image display apparatus in which the camera was mounted is coming to use widely. Corresponding to this, a polarizing plate having a through hole at a position corresponding to the camera unit is also widely used. In a polarizing plate having such a through-hole, there exist various considerations in a through-hole or its vicinity.

International Publication No. 2017/047510

The present invention has been made in order to solve the above conventional problems, and its main object is to provide a polarizing plate in which a through hole is formed in the vicinity of an end portion, and in which cracks around the through hole are significantly suppressed.

The polarizing plate which concerns on embodiment of this invention has a polarizer, the protective layer arrange|positioned at at least one side of the said polarizer, and an adhesive layer. The polarizing plate has a rectangular shape, and a through hole is formed therein. The thickness of the polarizer is 10 μm to 20 μm. The polarizing plate is in the state of being bonded to the glass plate through the pressure-sensitive adhesive layer, maintained at -40 ° C. for 30 minutes, and then maintained at 85 ° C. for 30 minutes after being subjected to a heat shock test repeating 100 cycles In the through hole portion The amount of deviation of the polarizing plate of is greater than 160 μm. The diameter of the through hole is 3 mm to 5 mm, and the through hole is formed within 11 mm from the long side, within 3 mm from the short side, within 3 mm from the long side, within 11 mm from the short side, or within 7 mm from the long side and within 5 mm from the short side. have.

In one embodiment, the two through holes are formed, and all of the through holes are within 11 mm from the long side, within 3 mm from the short side, within 3 mm from the long side, within 11 mm from the short side, or within 7 mm from the long side and within 5 mm from the short side. is formed within the

In one embodiment, the absorption axis of the said polarizer extends in the short side direction. In another embodiment, the absorption axis of the polarizer extends in the long side direction.

In another polarizing plate of the present invention, the diameter of the through hole is less than 3 mm, and the through hole is formed within 11 mm from the long side, within 3 mm from the short side, or within 3 mm from the long side and within 11 mm from the short side. In the polarizing plate, the absorption axis of the polarizer extends in the short side direction.

In another polarizing plate of the present invention, the diameter of the through hole is less than 3 mm, and the through hole is formed within 5 mm from the long side, within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side. In the polarizing plate, the absorption axis of the polarizer extends in the long side direction.

According to another aspect of the present invention, a set of polarizing plates is provided. This set of polarizing plates consists of a polarizing plate in which the absorption axis of the polarizer extends in the short side direction and a polarizing plate in which the absorption axis of the polarizer extends in the long side direction, and the through holes of each polarizing plate are formed at positions corresponding to each other.

Another polarizing plate set of the present invention consists of the other polarizing plate and the another polarizing plate, and the through hole of each polarizing plate is within 5 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side, They are also formed at positions corresponding to each other.

According to another aspect of the present invention, an image display apparatus is provided. This image display device includes an image display cell and the polarizing plate.

Another image display apparatus of the present invention includes an image display cell and a set of the polarizing plate. One polarizing plate in the set of the said polarizing plate is arrange|positioned at the visual recognition side of the said image display cell, and the other polarizing plate is arrange|positioned at the back side of the said image display cell.

According to the embodiment of the present invention, in the polarizing plate in which the through-hole is formed near the end portion, the diameter of the through-hole, the formation position of the through-hole, and the amount of deviation of the polarizing plate in the through-hole portion after the heat shock test (substantially the pressure-sensitive adhesive) By combining and optimizing the shift amount of the layers), it is possible to realize a polarizing plate in which cracks around the through hole are significantly suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic plan view explaining the polarizing plate by one Embodiment of this invention.
It is a schematic diagram explaining the formation position of the through-hole in the polarizing plate by embodiment of this invention.
1C is a schematic plan view for explaining a form in which a plurality of through holes are formed in a polarizing plate according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view taken along line II-II of the polarizing plate of FIG. 1 .
3 is an enlarged cross-sectional view of essential parts for explaining the shift in the through-hole portion in the polarizing plate according to the embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although specific embodiment of this invention is described with reference to drawings, this invention is not limited to these embodiment. In addition, in order to make it easy to see, the figure is shown typically, and the ratio of length, width|variety, thickness, etc. in a figure, an angle, etc. differ from reality.

A. Polarizer

A-1. Overall composition of the polarizer

1A is a schematic plan view illustrating a polarizing plate according to one embodiment of the present invention; Fig. 2 is a schematic cross-sectional view taken along the line II-II of the polarizing plate of Fig. 1A. The polarizing plate 100 of the illustrated example includes a polarizer 11 , a protective layer (hereinafter sometimes referred to as an outer protective layer) 12 disposed on one side of the polarizer 11 , and the other side of the polarizer 11 . It has the protective layer (Hereinafter, it may call an inner protective layer) 13 arrange|positioned on the side, and the adhesive layer 20. Either one of the outer protective layer 12 or the inner protective layer 13 may be omitted depending on the purpose and desired configuration. In embodiment of this invention, the thickness of the polarizer 11 is 10 micrometers - 20 micrometers, Preferably they are 10 micrometers - 15 micrometers.

The polarizing plate 100 typically has a rectangular shape as shown in FIG. 1A . In this specification, when referring to a "rectangular shape", as shown in FIG. 1A, each vertex includes a shape including a molded part, such as a chamfered R shape.

In the embodiment of the present invention, a through hole 30 is formed in the polarizing plate 100 . By forming the through hole, it is possible to prevent adverse effects on the camera performance, for example, when the image display device incorporates a camera. The through hole 30 is typically formed at or near the end of the polarizing plate, and is preferably formed at the corner as in the illustrated example. By forming the through hole at or near the end of the polarizing plate, when the polarizing plate is applied to an image display device, the influence on image display can be minimized. As for the planar shape of the through hole 30, any suitable shape may be employed depending on the purpose and desired configuration of the image display apparatus. As a representative example, a substantially circular shape similar to that of the illustrated example is exemplified. The through hole may be formed by various methods such as laser processing, cutting by an end mill, and punching by a Thompson blade or a Pinnacle (registered trademark) blade, for example.

In one embodiment, the diameter of the through hole is typically 3 mm to 5 mm. In this case, the absorption axis of the polarizer 11 may extend in the long side direction or may extend in the short side direction. That is, if the diameter of the through hole is within this range, cracks around the through hole can be significantly suppressed regardless of the direction of the absorption axis of the polarizer. In this embodiment, the through hole 30 is formed at a position within 11 mm from the long side, within 3 mm from the short side, within 3 mm from the long side, within 11 mm from the short side, or within 7 mm from the long side and within 5 mm from the short side. The through hole is preferably formed at a position within 7 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side; More preferably, it is formed at a position within 5 mm from the long side and within 3 mm from the short side; More preferably, it is formed at a position within 3 mm from the long side and within 3 mm from the short side. According to the embodiment of the present invention, even when the through hole is formed in the vicinity of the end portion, cracks around the through hole can be significantly suppressed. As a result, according to a design request, in an image display apparatus, for example, even when a camera part is formed at the maximum end, it can apply and can implement|achieve the polarizing plate excellent in durability. Accordingly, the polarizing plate according to the embodiment of the present invention has very high industrial and commercial value. In the present specification, the distance from the long side to the through hole means, as shown in FIG. 1B, the long side ( That is, it refers to the distance from the outer periphery of the polarizing plate) to the end of the through hole on the polarizing plate outer periphery side. Similarly, the distance from the short side to the through hole is, as shown in Fig. 1B, the short side (ie, the polarizing plate's It refers to the distance from the outer periphery) to the end of the through hole on the outer periphery of the polarizing plate.

A plurality of through holes may be formed as shown in Fig. 1C. Although two through-holes are formed in the example of illustration, three or more may be sufficient as the number of the through-holes. When two through-holes are formed, for example, as in FIG. 1C, both of the two through-holes are preferably within 11 mm from the long side, within 3 mm from the short side, within 3 mm from the long side, within 11 mm from the short side, or within 7 mm from the long side. It is formed at a position within 5 mm from the short side; More preferably, it is formed at a position within 7 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side; More preferably, it is formed at a position within 5 mm from the long side and within 3 mm from the short side; Particularly preferably, it is formed at a position within 3 mm from the long side and within 3 mm from the short side. In addition, when two through-holes are formed, for example as shown in FIG. 1C, these may be substituted by one elongate elliptical through-hole.

In another embodiment, the diameter of the through hole is typically less than 3 mm. The diameter of the through hole is preferably 0.5 mm to 2.5 mm. In this case, as an example, the absorption axis of the polarizer 11 extends in the short side direction. In this example, the through hole is formed at a position within 11 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 11 mm from the short side; preferably within 7 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side; More preferably, it is formed at a position within 5 mm from the long side and within 3 mm from the short side; More preferably, it is formed at a position within 3 mm from the long side and within 3 mm from the short side. As another example, the absorption axis of the polarizer 11 extends in the long side direction. In this example, the through hole is formed at a position within 5 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side; Preferably, it is formed at a position within 3 mm from the long side and within 3 mm from the short side. In a case where a plurality (for example, two) of through holes are formed, all of those through holes are formed at the above positions in any of the examples.

In the embodiment of the present invention, as shown in FIG. 3 , the polarizing plate 100 is a glass plate (which can correspond to a substrate of an image display cell) 120 with an adhesive layer 20 interposed therebetween. In, the amount of deviation (D) of the polarizing plate in the through hole portion after being subjected to a heat shock test repeating 100 cycles of holding at -40°C for 30 minutes and then holding at 85°C for 30 minutes for 30 minutes is greater than 160 μm . The shift amount (D) is preferably 180 µm or more, more preferably 200 µm or more, and still more preferably 220 µm or more. The upper limit of the shift amount D may be, for example, 300 μm. The shift amount D refers to the maximum part of the polarizing plate that moves away from the through-hole part when viewed in cross section. The reference of the through hole portion may be typically the lower end of the pressure-sensitive adhesive layer. That is, when the polarizing plate is shifted (to the right in the illustrated example) mainly due to the contraction of the polarizer 11, the adhesive layer 20 stays on the glass plate 120 to which it is adhered, so that the shift is recognized in the through hole portion. Moreover, as shown in FIG. 3, a polarizing plate shifts|deviates to the side away from a through-hole in a through-hole part typically (FIG. 3 right side), and the opposing part shifts|deviates so that it may protrude into a through-hole (FIG. 3 left). Thus, the shift|offset|difference of the polarizing plate in a through-hole part is a shift|offset|difference of an adhesive layer substantially. It is understood that the shift amount D is essentially preferably smaller. This is because light leakage due to shift in the image display device can be reduced. On the other hand, the inventors of the present invention found that by making the shift amount D equal to or greater than a predetermined amount, the residual stress in the vicinity of the through hole after the heat shock test can be released, and as a result, cracks in the vicinity of the through hole can be significantly suppressed. . That is, according to the embodiment of the present invention, by setting the deviation amount D to a predetermined value or more (preferably within a predetermined range), cracks around the through hole can be significantly suppressed while maintaining light leakage within an allowable range. .

The ratio (D/R) of the deviation amount D to the diameter R of the through hole is preferably 40% to 100%, more preferably 60% to 100%. If the D/R is within this range, it is possible to significantly suppress cracks around the through hole while keeping the light leakage in an acceptable range.

In embodiment of this invention, ratio (%) of the residual stress of a through-hole part with respect to the residual stress in the center of a polarizing plate becomes like this. Preferably it is 77 % or less. The ratio may vary depending on the diameter of the through hole. When the diameter of the through hole is 3 mm to 5 mm (eg, 4 mm), the ratio is more preferably 70% or less, still more preferably 68% or less, and particularly preferably 65% or less. When the diameter of the through hole is less than 3 mm (eg, 2 mm), the ratio is more preferably 76% or less, still more preferably 74% or less, and particularly preferably 72% or less. The lower limit of the ratio may be, for example, 50% regardless of the diameter of the through hole. If the residual stress ratio is within this range, cracks around the through hole can be significantly suppressed. This ratio of residual stress can be realized by adjusting the combination of the formation position of the through hole and the above-mentioned shift amount D. In addition, in this specification, the "residual stress of a through-hole part" means the residual stress of the part in which a residual stress becomes the largest in the outer periphery of a through-hole.

The polarizing plate by embodiment of this invention may further have arbitrary appropriate optical function layers according to the objective. As an optical function layer, a retardation layer, the conductive layer for touch panels, and a reflection type polarizer are mentioned, for example. The type, number, combination, arrangement position, and the like of the optical functional layers mounted on the polarizing plate may be appropriately set according to the purpose.

Preferably the aspect-ratio of the polarizing plate by embodiment of this invention is 1.3-2.5. In this case, the size of a polarizing plate is 145 mm - 155 mm in length and 65 mm - 75 mm in width, or 230 mm - 240 mm in length and 140 mm - 150 mm in width, for example. That is, the polarizing plate according to the embodiment of the present invention may be suitably used in a smartphone or tablet-type PC. As a smartphone size, 120 mm - 200 mm may be sufficient as length, and 30 mm - 120 mm may be sufficient as a width|variety, for example.

Hereinafter, the polarizer constituting the polarizing plate, the protective layer, and the pressure-sensitive adhesive layer will be described in detail.

A-2. polarizer

The polarizer is typically composed of a resin film containing a dichroic material. As the resin film, any suitable resin film that can be used as a polarizer can be employed. The resin film is typically a polyvinyl alcohol-based resin (hereinafter, referred to as “PVA-based resin”) film. A single-layered resin film may be sufficient as a resin film, and the laminated body of two or more layers may be sufficient as it.

As a specific example of the polarizer comprised from a single-layered resin film, the thing by which the dyeing process by iodine and the extending|stretching process (typically uniaxial stretching) were given to the PVA system resin film is mentioned. Dyeing with the said iodine is performed by immersing a PVA-type resin film in aqueous iodine, for example. Preferably the draw ratio of the said uniaxial stretching is 3-7 times. Extending|stretching may be performed after a dyeing process, and may be performed, dyeing|staining. Moreover, after extending|stretching, you may dye|dye. A swelling process, a crosslinking process, a washing process, a drying process, etc. are given to a PVA-type resin film as needed. For example, by immersing the PVA-based resin film in water before dyeing and washing with water, not only can the surface of the PVA-based resin film be cleaned of stains and anti-blocking agents, but also the PVA-based resin film can be swollen to prevent staining of dyeing. .

As a specific example of a polarizer obtained using a laminate, a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate A polarizer obtained by using is mentioned. A polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate is applied, for example, by applying a PVA-based resin solution to the resin substrate, drying it to form a PVA-based resin layer on the resin substrate, obtaining a laminate of a resin substrate and a PVA-based resin layer; It can be produced by stretching and dyeing the laminate to use the PVA-based resin layer as a polarizer. In this embodiment, extending|stretching includes extending|stretching by immersing a laminated body in boric-acid aqueous solution typically. In addition, the stretching may further include aerial stretching of the laminate at a high temperature (eg, 95° C. or higher) before stretching in an aqueous boric acid solution, if necessary. The obtained resin substrate/polarizer laminate may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), and the resin substrate is peeled from the resin substrate/polarizer laminate, It may be used by laminating an appropriate protective layer of The detail of the manufacturing method of such a polarizer is described in Unexamined-Japanese-Patent No. 2012-73580, and Japanese Patent No. 6470455, for example. The description of these patent documents is incorporated herein by reference.

The thickness of the polarizer is as described in A-1 above.

The polarizer preferably exhibits absorption dichroism at any one of wavelengths of 380 nm to 780 nm. The single transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more.

A-3. protective layer

The protective layer is formed of any suitable film that can be used as a protective layer of a polarizer. Specific examples of the material used as the main component of the film include cellulose resin such as triacetyl cellulose (TAC), polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyethersulfone, poly and transparent resins such as sulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based and acetate-based resins. Moreover, thermosetting resins, such as (meth)acrylic type, a urethane type, (meth)acryl urethane type, an epoxy type, silicone type, or ultraviolet curable resin etc. are mentioned. In addition to this, for example, glassy polymers, such as a siloxane type polymer, are also mentioned. Moreover, the polymer film described in Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007) can also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain can be used, for example, isobu and a resin composition comprising an alternating copolymer composed of ten and N-methylmaleimide and an acrylonitrile/styrene copolymer. The polymer film may be, for example, an extrusion molding of the resin composition.

The outer protective layer 12 (in particular, when the polarizing plate is a viewing-side polarizing plate) may be subjected to a surface treatment such as a hard coat treatment, an antireflection treatment, an anti-stick treatment, and an antiglare treatment, if necessary. In addition/or, in the outer protective layer 12, if necessary, a process for improving visibility when visually viewed through polarized sunglasses (typically, imparting a (other) circular polarization function, imparting a super-high phase difference) It may be implemented. By performing such a process, excellent visibility can be implement|achieved even when it is a case where a display screen is visually recognized through polarization lenses, such as polarized sunglasses. Therefore, the polarizing plate can also be suitably applied to an image display device that can be used outdoors.

The inner protective layer is preferably optically isotropic. In this 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. Here, "Re(λ)" is an in-plane retardation measured with light of a wavelength of λ nm at 23°C. For example, "Re(550)" is the phase difference in the thickness direction measured by the light of wavelength 550nm in 23 degreeC. Re(λ) is obtained by the formula: Re(λ)=(nx-ny)×d when the thickness of the layer (film) is d(nm). In addition, "Rth(λ)" is the phase difference in the thickness direction measured with the light of wavelength λnm in 23 degreeC. For example, "Rth(550)" is the phase difference in the thickness direction measured by the light of wavelength 550nm in 23 degreeC. Rth(λ) is obtained by the formula: Rth(λ)=(nx-nz)×d when the thickness of the layer (film) is d(nm). In addition, nx is the refractive index in the direction (ie, slow axis direction) in which the in-plane refractive index is maximum, ny is the refractive index in the direction orthogonal to the slow axis in the plane (ie, fast axis direction), nz is the refractive index in the thickness direction to be.

As the thickness of the protective layer, any suitable thickness may be employed. The thickness of the protective layer is, for example, 10 µm to 50 µm, preferably 20 µm to 40 µm. In addition, when the surface treatment is performed, the thickness of the protective layer is the thickness including the thickness of the surface treatment layer.

A-4. adhesive layer

The pressure-sensitive adhesive layer 20 is typically used for bonding a polarizing plate to an image display cell. The pressure-sensitive adhesive layer may be typically composed of an acrylic pressure-sensitive adhesive (acrylic pressure-sensitive adhesive composition). The acrylic pressure-sensitive adhesive composition typically includes a (meth)acrylic polymer as a main component. The (meth)acrylic polymer may be contained in the pressure-sensitive adhesive composition in a proportion of, for example, 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more among the solid content of the pressure-sensitive adhesive composition. The (meth)acrylic polymer contains an alkyl (meth)acrylate as a main component as a monomer unit. In addition, (meth)acrylate refers to an acrylate and/or a methacrylate. The alkyl (meth)acrylate may be contained in a ratio of preferably 80 wt% or more, more preferably 90 wt% or more, among the monomer components forming the (meth)acrylic polymer. Examples of the alkyl group of the alkyl (meth)acrylate include a linear or branched alkyl group having 1 to 18 carbon atoms. The average number of carbon atoms of the alkyl group is preferably 3 to 9, more preferably 3 to 6, respectively. A preferred alkyl (meth)acrylate is butylacrylate. As the monomer (copolymerized monomer) constituting the (meth)acrylic polymer, in addition to alkyl (meth)acrylate, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an amide group-containing monomer, an aromatic ring-containing (meth)acrylate, a heterocycle-containing vinylic A monomer etc. are mentioned. Representative examples of the copolymerization monomer include acrylic acid, 4-hydroxybutyl acrylate, phenoxyethyl acrylate, and N-vinyl-2-pyrrolidone. The acrylic pressure-sensitive adhesive composition may preferably contain a silane coupling agent and/or a crosslinking agent. As a silane coupling agent, an epoxy group containing silane coupling agent is mentioned, for example. As a crosslinking agent, an isocyanate type crosslinking agent and a peroxide type crosslinking agent are mentioned, for example. Moreover, the acrylic adhesive composition may contain antioxidant and/or a electrically conductive agent. By adjusting the type, number, combination and copolymerization ratio of the monomer units, the type, number, combination and mixing ratio of the silane coupling agent, and the type, number, combination and mixing ratio of the crosslinking agent, the acrylic pressure-sensitive adhesive composition having desired properties according to the purpose (As a result, a pressure-sensitive adhesive layer) can be obtained. As a result, in the embodiment of the present invention, the desired deviation amount D can be realized. Details of the pressure-sensitive adhesive layer or the acrylic pressure-sensitive adhesive composition, for example, Japanese Patent Application Laid-Open No. 2006-183022, Japanese Patent Application Laid-Open No. 2015-199942, Japanese Patent Application Laid-Open No. 2018-053114, Japanese Patent Application Laid-Open No. 2016-190996, International Publication No. 2018/008712, the disclosures of which are incorporated herein by reference.

The thickness of the pressure-sensitive adhesive layer is preferably 5 µm to 50 µm, more preferably 10 µm to 30 µm. If the thickness of an adhesive layer is such a range, the said desired shift|offset|difference amount D can be implement|achieved.

Storage elastic modulus (G') at -40 degreeC of an adhesive layer becomes like this. Preferably it is 1.0x10 ⁵ (Pa) or more, More preferably, it is 1.0x10 ⁶ (Pa) or more, More preferably, it is 1.0x10. ⁷ (Pa) or more, particularly preferably 1.0×10 ⁸ (Pa) or more. The storage modulus (G') may be, for example, 1.0×10 ⁹ (Pa) or less. If the storage elastic modulus in -40 degreeC of an adhesive layer is such a range, the said desired shift|offset|difference amount D can be implement|achieved.

B. Set of Polarizers

The polarizing plate according to item A above may be used as a viewing-side polarizing plate or may be used as a back-side polarizing plate. A set of polarizing plates can be provided by combining the polarizing plates of specific two embodiments among the polarizing plates described in item A above. Accordingly, embodiments of the present invention also include sets of such polarizing plates. In the set of polarizing plates, in the two polarizing plates constituting the set, respective through-holes are formed at positions corresponding to each other. In this specification, when "it is formed in the position corresponding to each other" means that two polarizing plates are superimposed, a through-hole overlaps.

In one embodiment, the set of polarizing plates includes: a polarizing plate having a through hole diameter of 3 mm to 5 mm and an absorption axis of the polarizer extending in the short side direction; The diameter of the through hole is 3 mm to 5 mm, and the absorption axis of the polarizer consists of a polarizing plate extending in the long side direction. In this case, the through holes of the two polarizing plates are typically within 11 mm from the long side, within 3 mm from the short side, within 3 mm from the long side, within 11 mm from the short side, or within 7 mm from the long side and within 5 mm from the short side; preferably within 7 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side; more preferably within 5 mm from the long side and within 3 mm from the short side; More preferably, it is a position within 3 mm from a long side and within 3 mm from a short side, and it is formed in the position corresponding to each other.

In another embodiment, the set of polarizing plates includes: a polarizing plate having a through hole diameter of less than 3 mm and an absorption axis of the polarizer extending in the short side direction; A diameter of the through hole is less than 3 mm, and the absorption axis of the polarizer is formed of a polarizing plate extending in the long side direction. In this case, the through holes of the two polarizing plates are typically located within 5 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side; Preferably, it is a position within 3 mm from a long side and less than 3 mm from a short side, and it is formed in the position corresponding to each other.

C. Image display device

A polarizing plate and a set of polarizing plates according to an embodiment of the present invention can be applied to an image display apparatus. Accordingly, an image display apparatus is also included in the embodiment of the present invention. In one embodiment, an image display apparatus contains an image display cell and a polarizing plate. The polarizing plate is a polarizing plate according to the embodiment of the present invention described in the above A section. The polarizing plate is bonded to the image display cell via an adhesive layer. In another embodiment, an image display device includes an image display cell and a set of polarizing plates. The set of polarizing plates is a set of polarizing plates according to the embodiment of the present invention described in section B above. In this case, one polarizing plate in the set of polarizing plates is arrange|positioned at the visual recognition side of the said image display cell, and the other polarizing plate is arrange|positioned at the back side of the said image display cell. Examples of the image display device include a liquid crystal display device, an organic electroluminescence (EL) display device, and a quantum dot display device.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The evaluation items in the Examples are as follows. In addition, unless otherwise indicated, "part" and "%" in Examples are based on weight.

(1) Deviation amount

The polarizing plate obtained by the Example and the comparative example was affixed on the glass plate (Matsunami Glass Corporation make, length 350mm x width 250mm x thickness 1.1mm) through an adhesive layer, and it was set as the test sample. This test sample was subjected to a heat shock test in which 100 cycles of holding at -40°C for 30 minutes and then at 85°C for 30 minutes were repeated. The rate of temperature increase and temperature decrease in the heat shock test was 10°C/min. After the test, the amount of shift of the polarizing plate (substantially the pressure-sensitive adhesive layer) of the through hole portion was measured with an optical microscope (MX61L) manufactured by OLYMPUS. In addition, the measurement was performed about three test samples, and the maximum value among three measured values was made into the shift|offset|difference amount.

(2) Ratio of the residual stress of the through hole portion to the residual stress of the center of the polarizing plate

It was calculated by stress analysis simulation. Simulations were performed using the following commercial software and methods.

Software: Marc, a nonlinear structural analysis software manufactured by MSC Software Corporation

Method: Finite Element Method (FEM)

(3) crack

The polarizing plate obtained by the Example and the comparative example was used for the heat shock test in the procedure similar to the "deviation amount" of said (1). The state of occurrence of cracks in the through-hole portion after the test was observed with an optical microscope (MX61L) manufactured by OLYMPUS, and evaluated on the basis of the following criteria.

AA: No cracks identified

A: Only small cracks with a length of less than 300 μm were confirmed

B: Cracks with a length of 300 µm to 1 mm were confirmed, but light leakage did not occur

C: A crack was significant, and light leakage occurred

<Production Example 1>

80.3 parts of butyl acrylate, 16 parts of phenoxyethyl acrylate, 3 parts of N-vinyl-2-pyrrolidone, 0.3 parts of acrylic acid and 4- A monomer mixture containing 0.4 parts of hydroxybutyl acrylate was charged. In addition, 0.1 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator is added to 100 parts of the monomer mixture (solid content) together with 100 parts by weight of ethyl acetate, and nitrogen gas is introduced while gently stirring to replace nitrogen. , a polymerization reaction was performed for 8 hours while maintaining the liquid temperature in the flask at around 55°C to prepare a solution of an acrylic polymer having a weight average molecular weight (Mw) of 1.5 million. 0.1 part of an isocyanate crosslinking agent (trade name: TAKENATE D160N, trimethylolpropane hexamethylene diisocyanate, manufactured by Mitsui Chemicals, Inc.), benzoyl peroxide (trade name: NYPER BMT 40SV, manufactured by NOF Corporation) per 100 parts of the solid content of the obtained acrylic polymer solution ) 0.3 parts, thiol group-containing silane coupling agent (trade name: X-41-1810, manufactured by Shin-Etsu Chemical Co., Ltd., alkoxy group content: 30%, thiol equivalent: 450 g/mol) 0.1 part, antioxidant (trade name) : Irganox 1010, hindered phenol type, manufactured by BASF Japan Ltd.) 0.2 parts, and conductive agent (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, manufactured by DKS Co. Ltd.) of ionic liquid) 5 parts were mix|blended, and the adhesive composition was obtained.

<Example 1>

As a polarizer, the film (12 micrometers in thickness) obtained by making a long polyvinyl alcohol (PVA)-type resin film contain iodine and uniaxially stretching in the longitudinal direction (MD direction) was used. On both sides of this polarizer, a long HC-TAC film serving as an outer protective layer and an elongated acrylic resin film (thickness 20 μm) serving as an inner protective layer were bonded together so that their longitudinal directions were aligned with each other. In addition, the HC-TAC film is a film in which a hard coat (HC) layer (thickness 7 µm) was formed on a triacetyl cellulose (TAC) film (thickness 25 µm), and the TAC film was bonded to the polarizer side. Using the pressure-sensitive adhesive composition of Production Example 1 on the surface of the inner protective layer, an adhesive layer (thickness of 20 µm) was formed to obtain a long polarizing plate. This polarizing plate was punched out in the shape in which the R part of R 7.0mm was formed in the size of 142.0 mm long and 66.8 mm wide at four corners. At this time, it punched so that the absorption axis direction of a polarizer might become a short side direction. Further, a through hole having a diameter of 4 mm was formed at a position of 2 mm from the long side and 2 mm from the short side. The through hole was formed by end milling. The feed speed of the end mill was 500 mm/min, the rotation speed was 2500 rpm, and the cutting amount was 0.1 mm. In this way, the polarizing plate which has a through-hole was produced. The obtained polarizing plate was used for evaluation of said (3). A result is shown in Table 1 with the detailed structure of a polarizing plate. In addition, in Table 1, "0 degree" means a long side direction, and "90 degree" means a short side direction.

<Example 2>

A polarizing plate was produced in the same manner as in Example 1 except that the formation position of the through hole was set at a position of 6 mm from the long side and 4 mm from the short side. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Comparative Examples 1-2 and Examples 3-4>

Except having made the formation position of a through-hole into the position shown in Table 1, it carried out similarly to Example 1, and produced the polarizing plate, respectively. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Example 5>

It carried out similarly to Example 1, and obtained the elongate polarizing plate. This polarizing plate was punched out to a size of 142.0 mm long and 66.8 mm wide. At this time, it punched so that the absorption axis direction of a polarizer might become a long side direction. The following procedure carried out similarly to Example 1, and produced the polarizing plate which has a through-hole of diameter 4mm at the position of 2 mm from a long side, and 2 mm from a short side. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Example 6>

A polarizing plate was produced in the same manner as in Example 5 except that the formation position of the through hole was set at a position of 6 mm from the long side and 4 mm from the short side. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Comparative Examples 3 to 4 and Examples 7 to 8>

Except having made the formation position of a through hole into the position shown in Table 1, it carried out similarly to Example 5, and produced the polarizing plate, respectively. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Example 9>

A polarizing plate was produced in the same manner as in Example 1 except that a through hole having a diameter of 2 mm was formed. In addition, the through hole was formed with a CO ₂ laser. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Comparative Example 5>

A polarizing plate was produced in the same manner as in Example 9 except that the formation position of the through hole was set at a position of 6 mm from the long side and 4 mm from the short side. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Comparative Examples 6-7 and Examples 10-11>

Except having made the formation position of a through-hole into the position shown in Table 1, it carried out similarly to Example 9, and produced the polarizing plate, respectively. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Example 12>

A polarizing plate was produced in the same manner as in Example 5 except that a through hole having a diameter of 2 mm was formed. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Comparative Example 8>

A polarizing plate was produced in the same manner as in Example 12 except that the formation position of the through hole was set at a position of 6 mm from the long side and 4 mm from the short side. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

<Comparative Examples 9 to 12>

Except having made the formation position of a through-hole into the position shown in Table 1, it carried out similarly to Example 12, and produced the polarizing plate, respectively. The obtained polarizing plate was used for evaluation similar to Example 1. A result is shown in Table 1 with the detailed structure of a polarizing plate.

As becomes apparent from Table 1, in the polarizing plate of the Example of this invention, generation|occurrence|production of the crack in the through-hole part after a heat shock test is suppressed remarkably.

(industrial applicability)

The polarizing plate of the present invention is suitably used for an image display device, and in particular can be suitably used for an image display device having a camera unit typified by a smart phone, a tablet PC, or a smart watch.

11 Polarizer 12 Outer protective layer
13 Inner protective layer 20 Adhesive layer
30 through hole 100 polarizer

Claims (10)

A rectangular polarizing plate having a polarizer, a protective layer disposed on at least one side of the polarizer, and an adhesive layer, and in which a through hole is formed, the polarizing plate comprising:
The thickness of the polarizer is 10㎛ ~ 20㎛,
In the through-hole portion after being subjected to a heat shock test in which the polarizing plate is bonded to the glass plate through the pressure-sensitive adhesive layer, maintained at -40°C for 30 minutes, and then maintained at 85°C for 30 minutes, repeated 100 cycles In the The amount of deviation of the polarizing plate of is greater than 160㎛,
The diameter of the through hole is 3 mm to 5 mm,
A polarizing plate in which the through hole is formed within 11 mm from the long side, within 3 mm from the short side, within 3 mm from the long side, within 11 mm from the short side, or within 7 mm from the long side and within 5 mm from the short side. The method of claim 1,
The two through-holes are formed,
A polarizing plate in which the through holes are all formed within 11 mm from the long side, within 3 mm from the short side, within 3 mm from the long side, within 11 mm from the short side, or within 7 mm from the long side and within 5 mm from the short side. 3. The method of claim 1 or 2,
A polarizing plate in which an absorption axis of the polarizer extends in a short-side direction. 3. The method of claim 1 or 2,
A polarizing plate in which an absorption axis of the polarizer extends in a long side direction. A rectangular polarizing plate having a polarizer, a protective layer disposed on at least one side of the polarizer, and an adhesive layer, and in which a through hole is formed, the polarizing plate comprising:
The thickness of the polarizer is 10㎛ ~ 20㎛, the absorption axis of the polarizer extends in the short side direction,
In the through-hole portion after being subjected to a heat shock test in which the polarizing plate is bonded to the glass plate through the pressure-sensitive adhesive layer, maintained at -40°C for 30 minutes, and then maintained at 85°C for 30 minutes, repeated 100 cycles In the The amount of deviation of the polarizing plate of is greater than 160㎛,
The diameter of the through hole is less than 3 mm,
A polarizing plate in which the through hole is formed within 11 mm from the long side, within 3 mm from the short side, or within 3 mm from the long side and within 11 mm from the short side. A rectangular polarizing plate having a polarizer, a protective layer disposed on at least one side of the polarizer, and an adhesive layer, and in which a through hole is formed, the polarizing plate comprising:
The thickness of the polarizer is 10㎛ ~ 20㎛, the absorption axis of the polarizer extends in the long side direction,
In the through-hole portion after being subjected to a heat shock test in which the polarizing plate is bonded to the glass plate through the pressure-sensitive adhesive layer, maintained at -40°C for 30 minutes, and then maintained at 85°C for 30 minutes, repeated 100 cycles In the The amount of deviation of the polarizing plate of is greater than 160㎛,
The diameter of the through hole is less than 3 mm,
A polarizing plate in which the through hole is formed within 5 mm from the long side, within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side. It consists of the polarizing plate according to claim 3 and the polarizing plate according to claim 4,
A set of polarizing plates in which through holes of each polarizing plate are formed at positions corresponding to each other. It consists of the polarizing plate of Claim 5 and the polarizing plate of Claim 6,
A set of polarizing plates in which the through-holes of each polarizing plate are within 5 mm from the long side and within 3 mm from the short side, or within 3 mm from the long side and within 5 mm from the short side, and are formed at positions corresponding to each other. The image display device containing an image display cell and the polarizing plate in any one of Claims 1-6. An image display cell and the set of the polarizing plate of Claim 7 or 8 are included,
The image display device in which one polarizing plate in the set of the said polarizing plate is arrange|positioned on the visual recognition side of the said image display cell, and the other polarizing plate is arrange|positioned at the back side of the said image display cell.

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