KR102343171B1 - Method for manufacturing an image display device and an image display device obtained by the manufacturing method - Google Patents

Abstract

A simple method for manufacturing a polarizing plate with a substrate capable of maintaining excellent optical properties even in a humidified environment and preventing color fading is provided. The manufacturing method of the polarizing plate with a board|substrate of this invention prepares the board|substrate which has a larger size than a polarizing plate and a polarizing plate; laminating the substrate and the polarizing plate such that the substrate extends-protrudes from the outer periphery of the polarizing plate; forming an encapsulation portion covering the peripheral cross-section of the polarizing plate; and cutting the substrate and the encapsulation portion to a predetermined size leaving a portion extending-projecting a predetermined length from the peripheral edge of the polarizing plate.

Description

Method for manufacturing an image display device and an image display device obtained by the manufacturing method

The present invention relates to a method for manufacturing an image display device and an image display device obtained by the manufacturing method.

BACKGROUND ART In image display devices (eg, liquid crystal display devices, organic EL display devices, quantum dot display devices), a polarizing plate is disposed on at least one side of a display cell in many cases due to the image formation method thereof. However, the polarizing plate has a problem of durability in that the optical properties of the polarizing film, which substantially dominates the mechanical characteristics of the polarizing plate, are deteriorated in a humidified environment. More specifically, in a polarizing film, the polarization performance of an edge part lose|disappears under a humidified environment, and what is called color loss may generate|occur|produce in an image display apparatus as a result as a result.

Japanese Laid-Open Patent Publication No. 2000-338329

The present invention has been made to solve the above problems, and its main object is to provide an image display device capable of maintaining excellent optical properties even in a humidified environment and preventing color fading, and a simple manufacturing method thereof.

The method for manufacturing an image display device of the present invention comprises: preparing a polarizing plate and a substrate having a size larger than that of the polarizing plate; stacking the substrate and the polarizing plate so that the substrate extends and protrudes from the outer periphery of the polarizing plate; forming an encapsulation unit covering the peripheral end face of the polarizing plate; and cutting the substrate and the encapsulation portion to a predetermined size while leaving a portion extending-protruding a predetermined length from the peripheral edge of the polarizing plate.

In one embodiment, the substrate is a glass plate. In another embodiment, the substrate is a resin film.

In one embodiment, in the manufacturing method, the substrate and the polarizing plate are laminated such that the substrate extends-protrudes from all four sides constituting the outer periphery of the polarizing plate.

In one embodiment, the substrate is a display cell substrate of an image display device selected from a liquid crystal display device, an organic EL display device, and a quantum dot display device.

In one embodiment, the cutting is performed by irradiating laser light.

In one embodiment, the length of the extending-projecting portion of the encapsulation portion after the cutting is from 10 μm to 500 μm.

In one embodiment, the moisture permeability of the sealing part after the said cutting|disconnection is 300 g/m<2>/24hr or less.

According to another aspect of the present invention, an image display apparatus is provided. This image display device has a polarizing plate and a substrate having an extending-projecting portion of a predetermined length from the peripheral edge of the polarizing plate, and a sealing portion formed in the extending-projecting portion to cover the peripheral end face of the corresponding polarizing plate.

According to the present invention, in the method for manufacturing an image display device, an encapsulation portion is formed in a portion extending-protruding from the polarizing plate of the substrate to seal the peripheral end face of the polarizing plate, and the encapsulation portion and the extending-projecting portion of the corresponding substrate are separated from the polarizing plate. By cutting while leaving a predetermined length from the peripheral edge, excellent optical properties can be maintained even in a humidified environment, and an image display device in which color fading is prevented can be manufactured simply.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic for demonstrating the manufacturing method of the image display apparatus which concerns on one Embodiment of this invention.
2 is a schematic diagram for explaining the calculation of the amount of color loss.
It is an image which shows the amount of color loss after the humidification test of the polarizing plate with a board|substrate as an image display device substitute of Example 1. FIG.
It is an image which shows the amount of color loss after the humidification test of the polarizing plate with a board|substrate as an image display device substitute of the comparative example 1. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

A. Manufacturing method of image display device

The manufacturing method of the image display apparatus of this invention prepares the board|substrate which has a larger size than a polarizing plate and this polarizing plate; stacking the substrate and the polarizing plate so that the substrate extends from the outer periphery of the polarizing plate and protrudes; forming an encapsulation unit covering the peripheral cross-section of the polarizing plate; and cutting the substrate and the encapsulation portion to a predetermined size while leaving an extension-protruding portion of a predetermined length from the peripheral edge of the polarizing plate.

The present invention is applicable to any laminated structure of a substrate and a polarizing plate in an image display device. The substrate may typically be a display cell substrate of an image display device. A liquid crystal display device, an organic EL display device, and a quantum dot display device are mentioned as a representative example of an image display device. As a display cell board|substrate, the board|substrate which seals a color filter from both surfaces in the board|substrate of a liquid crystal cell, the board|substrate of an organic electroluminescent cell, the board|substrate of a quantum dot display cell, and a liquid crystal display device is mentioned, for example. In one embodiment of the manufacturing method of the present invention, a substrate and a polarizing plate are laminated, a sealing portion is formed in the laminate to produce a polarizing plate with a substrate, and an image display device is obtained by using the polarizing plate with a substrate as a display cell substrate can In another embodiment, the manufacturing method of this invention can obtain an image display device by producing a display cell, laminating|stacking a polarizing plate on the board|substrate of the said display cell, and then forming a sealing part. Hereinafter, as a representative example, embodiment using a polarizing plate with a board|substrate as a display cell board|substrate is demonstrated.

A-1. Preparation of Polarizer and Substrate

First, as shown to Fig.1 (a), the polarizing plate 10 and the board|substrate 20 are prepared. Hereinafter, a polarizing plate and a board|substrate are demonstrated in detail.

A-1-1. Polarizer

The polarizing plate has a polarizing film and a protective film disposed on at least one side of the polarizing film. In the embodiment of the present invention, the polarizing film is composed of a polyvinyl alcohol-based resin (hereinafter referred to as 'PVA-based resin') film containing iodine. When the polarizing film contains iodine, the effect of providing a sealing part becomes remarkable. The thickness of the polarizing film is typically 8 μm or less. When the polarizing film contains iodine and its thickness is so thin, the iodine density in the polarizing film increases and the stability of iodine due to humidification tends to decrease, so that the effect of providing an encapsulation part becomes more remarkable. A protective film may be arrange|positioned on one side of a polarizing film, and may be arrange|positioned on both sides. When a protective film is arrange|positioned on one side of a polarizing film, it may be arrange|positioned at the display cell side, and may be arrange|positioned on the opposite side to a display cell. Practically, an adhesive layer is provided as the outermost layer on the side of a display cell of a polarizing plate, and a polarizing plate is bonded to a display cell through the said adhesive layer. In addition, when simply referred to as a protective film in this specification, it means a film (a component of a polarizing plate) that protects such a polarizing film, and is different from the above-mentioned surface protection film (a film that temporarily protects the polarizing plate during operation).

A-1-1-1. polarizing film

As described above, the polarizing film is composed of a PVA-based resin film containing iodine. A polarizing film may be formed from the resin film of a single layer, and may be formed from the laminated body of two or more layers.

As a specific example of a polarizing film formed of a single-layer resin film, a hydrophilic polymer film such as a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, or an ethylene/vinyl acetate copolymer-based partially saponified film, iodine or a dichroic dye Polyene-type oriented films, such as a thing to which the dyeing process and extending|stretching process by the dichroic substance were given, and the dehydration-processed material of PVA, and the dehydrochloric acid-treated material of polyvinyl chloride, etc. are mentioned. Preferably, a polarizing film obtained by dyeing a PVA-based film with iodine and uniaxially stretching it is used in view of excellent optical properties. The dyeing with iodine is performed, for example, by immersing the PVA-based film in an aqueous iodine solution. Preferably the draw ratio of the said uniaxial stretching is 3-7 times. Extending|stretching may be performed after dyeing process, and may be performed while dyeing|staining. Moreover, you may dye|stain after extending|stretching. A swelling process, a crosslinking process, a washing process, a drying process, etc. are given to a PVA type film as needed. For example, by immersing the PVA-based film in water and washing with water before dyeing, it is possible not only to wash the surface of the PVA-based film from contamination and blocking agents, but also to swell the PVA-based film to prevent staining of dyeing.

As a specific example of a polarizing film 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 resin substrate and a PVA-based resin layer coated on the resin substrate The polarizing film obtained using a laminated body is mentioned. A polarizing film obtained by using a laminate of a resin substrate and a PVA-based resin layer applied and formed on the resin substrate is formed by, for example, applying a PVA-based resin solution to the resin substrate and 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 extending|stretching and dyeing the said laminated body, and making a PVA-type resin layer into a polarizing film. 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 air stretching the laminate at a high temperature (eg, 95° C. or higher) before stretching in an aqueous boric acid solution, if necessary. The obtained laminate of the resin substrate / polarizing film may be used as it is (that is, the resin substrate may be used as a protective film for the polarizing film), and the resin substrate is peeled from the laminate of the resin substrate / polarizer, Any suitable protective film may be laminated and used. The detail of the manufacturing method of such a polarizing film is described in Unexamined-Japanese-Patent No. 2012-73580, for example. This publication is incorporated herein by reference in its entirety.

Any suitable resin may be employed as the PVA-based resin forming the PVA-based resin film. For example, polyvinyl alcohol and an ethylene-vinyl alcohol copolymer are mentioned. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. An ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The degree of saponification of the PVA-based resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.9 mol%, more preferably 99.0 mol% to 99.5 mol%. The degree of saponification can be obtained according to JIS K 6726-1994. By using the PVA-type resin of such a saponification degree, the polarizing film excellent in durability can be obtained. When the degree of saponification is too high, there is a risk of gelation.

The average degree of polymerization of the PVA-based resin may be appropriately selected depending on the purpose. The average degree of polymerization is usually from 1000 to 10000, preferably from 1200 to 5000, more preferably from 1500 to 4500. In addition, an average degree of polymerization can be calculated|required according to JISK6726-1994.

As described above, the polarizing film contains iodine. The polarizing film is substantially a PVA-based resin film in which iodine is adsorbed and oriented. The iodine concentration in the PVA-based resin film is, for example, 5.0% by weight to 12.0% by weight. In addition, the boric acid density|concentration in a PVA-type resin film is 12 weight% - 25 weight%, for example.

The thickness of the polarizing film is typically 8 µm or less, preferably 7 µm or less, and more preferably 6 µm or less as described above. On the other hand, the thickness of the PVA-based resin film is preferably 1.0 µm or more, and more preferably 2.0 µm or more.

The polarizing film preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizing film is preferably 40.0% to 46.0%, more preferably 41.0% to 45.0%. The polarization degree of the polarizing film is preferably 99.9% or more, more preferably 99.95% or more, and still more preferably 99.98% or more. When the polarizing plate is applied to a reflective liquid crystal display device or an organic EL display device, the polarization degree of the polarizing film is preferably 90% or more, more preferably 93% or more, and still more preferably 95% or more. As will be described later, by providing an encapsulant that covers the peripheral end face of an image display panel including a polarizing film, such excellent optical properties (excellent balance of single transmittance and polarization degree) and excellent durability (such excellent optical properties even in humidified environments) properties that can be maintained) are compatible.

A-1-1-2. protective film

The protective film is composed of any suitable film that can be used as a protective film for the polarizing film. Specific examples of the material used as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyethersulfone, and polysulfone. Transparent resins, such as a phone type, polystyrene type, polynorbornene type, polyolefin type, (meth)acrylic type, acetate type, etc. are mentioned. Moreover, thermosetting resins, such as (meth)acrylic type, a urethane type, a (meth)acryl urethane type, an epoxy type, a 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 of 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 a side chain can be used, for example, isobutene and N - A resin composition having an alternating copolymer composed of -methylmaleimide and an acrylonitrile-styrene copolymer is mentioned. The polymer film may be, for example, an extrusion molding of the resin composition.

In embodiment of this invention, as above-mentioned, you may use the resin base material used for manufacture of a polarizing plate as a protective film as it is.

In a polarizing plate disposed on the viewing side, when the protective film is disposed on the viewing side of the polarizing film, the protective film may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, anti-glare treatment, etc. if necessary. may be performed.

As for the thickness of the protective film, any suitable thickness may be employed as long as the effect of the present invention is obtained. The thickness of the protective film is, for example, 10 µm to 40 µm, preferably 10 µm to 30 µm. In addition, when surface treatment is performed, the thickness of a protective film is the thickness including the thickness of a surface treatment layer.

When disposing a protective film (inner protective film) on the display cell side of the polarizing film, in one embodiment, it is preferable that the said inner protective film is 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. Re(550) of the inner protective film is preferably 0 nm to 8 nm, more preferably 0 nm to 6 nm, still more preferably 0 nm to 3 nm. Rth (550) of the inner protective film is preferably -8 nm to +8 nm, more preferably -6 nm to +6 nm, and still more preferably -3 nm to +3 nm. In addition, 'Re(550)' is an in-plane retardation measured with light having a wavelength of 550 nm at 23°C. Re(550) can be obtained by the formula: Re=(nx-ny)×d when the thickness of the layer (film) is d(nm). In addition, 'Rth(550)' is the phase difference in the thickness direction measured with light of wavelength 550nm at 23 degreeC. Rth(λ) can be obtained by the formula: Rth=(nx-nz)×d when the thickness of the layer (film) is d(nm).

In another embodiment, the inner protective film may have Re (550) capable of functioning as a so-called λ/4 plate. Such an embodiment can be applied, for example, when the polarizing plate functions as a circularly polarizing plate and is used as an antireflection film of a reflective liquid crystal display device or an organic EL display device. In this case, Re(550) is preferably 120 nm to 160 nm, more preferably about 140 nm. In this case, the inner protective film may be disposed such that its slow axis forms an angle of preferably 40° to 50°, more preferably about 45° with respect to the absorption axis of the polarizing film.

A-1-2. Board

Any suitable configuration may be employed as the substrate. For example, a glass plate may be sufficient as a board|substrate, and a resin film may be sufficient as it. The substrate has a size larger than that of the polarizing plate. When the substrate is laminated with a polarizing plate, it preferably has a size that extends from the outer periphery of the polarizing plate to a predetermined length, and more preferably extends and protrudes by a predetermined length from all four sides constituting the outer periphery of the polarizing plate. has

Any suitable glass plate may be employed as the glass plate. According to classification according to a composition, glass which comprises a glass plate is mentioned, for example, soda-lime glass, boric-acid glass, aluminosilicate glass, and quartz glass. Moreover, according to classification according to an alkali component, an alkali free glass and low alkali glass are mentioned. The content of the alkali metal component of the glass (eg, Na ₂ O, K ₂ O, Li ₂ O) is preferably 15% by weight or less, and more preferably 10% by weight or less.

The light transmittance at a wavelength of 550 nm of the glass plate is preferably 85% or more. Preferably the refractive index in wavelength 550nm of a glass plate is 1.4-1.65. The density of the glass sheet is preferably from ^{2.3g / cm 3 ~3.0g / cm 3} , more preferably from ^{2.3g / cm 3 ~2.7g / cm 3} .

The thickness of a glass plate becomes like this. Preferably they are 0.1 mm - 1.0 mm, More preferably, they are 0.2 mm - 0.6 mm.

As a glass plate, a commercially available glass plate may be used as it is, and a commercially available glass plate may be grind|polished so that it may become a desired thickness and may be used. Commercially available glass plates include, for example, '7059', '1737' or 'EAGLE2000' manufactured by Corning, 'AN100' manufactured by Asahi Glass, 'NA-35' manufactured by NH Techno Glass, 'OA' manufactured by Nippon Electric Corporation -10', 'D263' manufactured by SCHOTT, or 'AF45' can be mentioned.

Any suitable resin film may be employed as the resin film. The resin film is typically a transparent resin film. Examples of the material constituting the resin film include polyimide and polyamideimide. These may be used independently and may be used in combination.

The thickness of the resin film is preferably 10 µm to 200 µm, more preferably 20 µm to 100 µm.

A-2. Lamination of polarizing plate and substrate

Next, as shown to Fig.1 (a), the polarizing plate 10 and the board|substrate 20 are laminated|stacked. The polarizing plate 10 and the substrate 20 may be typically laminated with any suitable pressure-sensitive adhesive layer (not shown) interposed therebetween. The lamination is performed so that the substrate extends-protrudes from the outer periphery of the polarizing plate as shown in FIG.

If necessary, a surface protection film (not shown) may be temporarily attached to the surface of the polarizing plate 10 on the opposite side to the substrate 20 . Accordingly, the polarizing plate can be properly protected in the formation of the encapsulation unit described later and the cutting of the encapsulation unit and the substrate. The surface protection film is peeled off at the time of final use of a polarizing plate with a board|substrate (substantially an image display apparatus). The peeling removal of the surface protection film may be performed at any suitable timing after the formation of the encapsulation portion and the cutting of the encapsulation portion and the substrate.

A-3. Encapsulation Formation

Next, as shown in FIG.1(b), the sealing part 30 which covers the peripheral end surface of the polarizing plate 10 is formed. By covering the peripheral end face of the polarizing plate with the encapsulation portion, it is possible to maintain the optical properties of the polarizing plate (polarizing film) even under a humidified environment and, as a result, to improve the durability of the image display device. Therefore, it is preferable that the sealing part has a barrier function. As used herein, the term 'having a barrier function' means controlling the amount of oxygen and/or water vapor penetrating into the polarizing film to substantially block the polarizing film from them.

The encapsulation portion is typically formed by disposing the pressure-sensitive adhesive composition so as to cover the peripheral end face of the polarizing plate. In one embodiment, the encapsulation portion may be formed by disposing (eg, applying, disposing of a sheet-like pressure-sensitive adhesive) the pressure-sensitive adhesive composition on the extended-projecting portion of the substrate. The sealing part covers the peripheral end surface of a polarizing plate, the said peripheral end surface should just be sealed, and it does not need to be closely_contact|adhered to the said peripheral end surface. Moreover, the sealing part should just cover the peripheral end surface of a polarizing plate, Therefore, you may cover parts other than a peripheral end surface with a peripheral end surface. For example, the sealing part may cover the surface (upper surface in the figure) of the side away from the board|substrate of a polarizing plate together with a peripheral end surface. In this case, the whole may be covered with the said surface, and only a predetermined|prescribed part may be covered.

As an adhesive composition, the rubber-type adhesive composition which uses a rubber-type polymer as a base polymer is mentioned, for example.

As the rubber-based polymer, for example, a conjugated diene-based polymer obtained by polymerizing one type of conjugated diene compound, a conjugated diene-based copolymer obtained by polymerizing two or more types of conjugated diene compound, and a conjugated diene compound and an aromatic vinyl compound. Conjugated diene copolymers obtained and their hydrogenated products are mentioned.

The conjugated diene compound is not particularly limited as long as it is a monomer having a polymerizable conjugated diene. Specific examples of the conjugated diene compound include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, and 1,3-hepta. diene and 1,3-hexadiene. Among them, 1,3-butadiene and isoprene are preferable from the viewpoint of industrial availability. A conjugated diene compound may be used independently and may be used in combination.

As an aromatic vinyl compound, if it is a monomer which has an aromatic vinyl structure copolymerizable with a conjugated diene compound, it will not specifically limit. Specific examples of the aromatic vinyl compound include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, the viewpoint of industrial availability to styrene is preferable. An aromatic vinyl compound may be used independently and may be used in combination.

The diene copolymer may be a random copolymer or a block copolymer. Moreover, you may copolymerize compounds other than a conjugated diene compound and an aromatic vinyl compound, and you may obtain a diene type copolymer.

In the conjugated diene-based copolymer obtained by copolymerizing the conjugated diene compound and the aromatic vinyl compound, the molar ratio of the conjugated diene compound and the aromatic vinyl compound is preferably conjugated diene compound/aromatic vinyl compound = 10/90 to 90/10 (mol%). .

Specific examples of such a conjugated diene-based (co)polymer include butadiene rubber (BR), isoprene rubber (IR), styrene-butadiene copolymer (SBR), butadiene-isoprene-styrene random copolymer, isoprene-styrene random copolymer, and styrene-isoprene block copolymer (SIS), butadiene-styrene copolymer, styrene-ethylene-butadiene block copolymer (SEBS), and acrylonitrile-butadiene rubber (NBR). These may be used independently and may be used in combination. Among these, an isoprene-styrene copolymer is preferable. Moreover, these hydrogenated substances can also be used preferably.

As the rubber-based polymer, in addition to the conjugated diene-based (co)polymer, isobutylene (IB), styrene-isobutylene-styrene block copolymer (SIBS), styrene-ethylenepropylene copolymer-styrene block copolymer, and the like can also be used. A rubber-type polymer may be used independently and may be used in combination.

The rubber-based polymer that can be used in the present invention is preferably 50% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, of the conjugated diene-based (co)polymer in the entire rubber-based polymer. Preferably it contains 90 wt% or more. The upper limit of the content of the conjugated diene-based (co)polymer is not particularly limited, and may be 100% by weight (ie, a rubber-based polymer comprising only the conjugated diene-based (co)polymer).

As described above, the pressure-sensitive adhesive composition includes a rubber-based polymer as a base polymer. The content of the rubber polymer in the pressure-sensitive adhesive composition is preferably 40% by weight or more, more preferably 50% by weight or more, still more preferably 60% by weight or more. The upper limit of the content of the rubber-based polymer is not particularly limited, and is, for example, 90% by weight or less.

In addition to the rubber-based polymer, the pressure-sensitive adhesive composition may further contain any appropriate additives. Specific examples of the additive include a crosslinking agent (eg, polyisocyanate, epoxy compound, alkyl etherified melamine compound, etc.), tackifier (eg, rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble phenol resin, vinyltoluene resin, etc.); plasticizers, fillers (eg, layered silicates, clay materials, etc.), and antioxidants. The type, combination, and amount of additives added to the pressure-sensitive adhesive composition may be appropriately set according to the purpose. Content (total amount) of the additive in an adhesive composition becomes like this. Preferably it is 60 weight% or less, More preferably, it is 50 weight% or less, More preferably, it is 40 weight% or less.

The thickness of the sealing part 30 formed in this way becomes like this. Preferably it is 30 micrometers - 1000 micrometers, More preferably, they are 50 micrometers - 500 micrometers. In the present specification, unless otherwise specified, the 'thickness of the encapsulation portion' is the thickness in the direction extending outward from the peripheral end face of the polarizing plate (that is, the thickness of the encapsulation portion corresponds to the length of the extended-projection portion of the substrate).

A-4. Cutting of encapsulation and substrate

Next, as shown in FIG. 1(c) , the encapsulation portion 30 and the substrate 20 are cut leaving a portion extending-protruding a predetermined length from the peripheral edge of the polarizing plate. As a result, as shown in FIG.1(d), the sealing part 40 which has a predetermined thickness is formed. The thickness of the sealing part 40 after cutting becomes like this. Preferably it is 10 micrometers - 500 micrometers, More preferably, they are 20 micrometers - 300 micrometers.

Cutting may be performed mechanically, and may be performed by irradiating a laser beam.

Mechanical cutting includes price processing and end milling.

The laser light preferably comprises light of a wavelength of at least 1500 nm or less. The laser light more preferably includes light having a wavelength of 100 pm to 1000 nm, further preferably includes light having a wavelength of 400 nm to 900 nm, and particularly preferably includes light having a wavelength of 420 nm to 680 nm. In one embodiment, the laser light has a peak wavelength in the above range. According to the laser beam containing such a wavelength, it can cut|disconnect favorably over the thickness direction of the upper and lower sides of a sealing part.

Examples of the laser include solid lasers such as YAG laser, YLF laser, YVO4 laser and titanium sapphire laser, argon ion laser, gas laser including krypton ion laser, fiber laser, semiconductor laser, and dye laser. A solid-state laser is preferably used.

A short pulse laser (a laser irradiating light having a pulse width of 1 nanosecond or less, for example, a picosecond laser or a femtosecond laser, etc.) is preferably used as the laser. For the purpose of suppressing thermal damage to the encapsulation, a pulse width of 500 picoseconds or less (eg, 10 picoseconds to 50 picoseconds) is particularly preferred. By suppressing thermal damage, a beautiful, uniform and smooth cut surface can be obtained.

The laser light irradiation condition can be set to any suitable condition. For example, when a solid-state laser (YVO4 laser) is used, the pulse energy is preferably 10 µJ to 150 µJ, more preferably 25 µJ to 71 µJ. The scanning speed is preferably 10 mm/sec to 10000 mm/sec, more preferably 100 mm/sec to 1000 mm/sec. The repetition frequency is, for example, 100 Hz to 12480 Hz. The scan pitch is preferably 10 µm to 50 µm. The beam shape at the irradiation position of the laser light can be appropriately set according to the purpose. The shape of the beam may be, for example, a circular shape or a line shape. Any suitable means may be employed as means for forming the beam shape into a predetermined shape. For example, laser irradiation may be carried out through a mask having a predetermined opening, or beam shaping may be performed using a diffractive optical element or the like. For example, when the beam shape is circular, the focal diameter (spot diameter) is preferably 50 µm to 60 µm. In addition, the input energy of the pulse laser is preferably 20000 μJ/m 2 to 100000 μJ/m 2 , more preferably 25000 μJ/m 2 to 75000 μJ/m m 2 . In addition, the input energy E (microJ/mm<2>) can be calculated|required by the following formula.

E=(e×M)/(V×p)

e: pulse energy (J)

M: repetition frequency (Hz)

V: Scan speed (mm/sec)

p: scan pitch (mm)

The irradiation form (scanning mode) of the laser light can be appropriately set according to the purpose. The laser beam may be scanned, for example, in a linear shape, in an S-shape, or in a vortex shape, or a combination thereof.

The encapsulation unit 40 formed as described above has a barrier property, and typically has a barrier property against moisture and gas (eg, oxygen). The water vapor transmission rate (water vapor transmission rate) of the sealing part 40 under the conditions of 40 ° C. and 90% RH is preferably 300 g/m 2 /24 hr or less, more preferably 100 g/m 2 /24 hr or less, and still more preferably 50 g/m 2 /24 hr or less, particularly preferably 25 g/m 2 /24 hr or less. The lower limit of the water vapor transmission rate is, for example, 0.01 g/m 2 /24 hr, preferably less than the detection limit. If the moisture permeability of the encapsulation unit 40 is within such a range, the image display panel can be favorably protected from moisture and oxygen in the air. In addition, the water vapor transmission rate can be measured according to JIS Z0208.

As described above, as shown in Fig. 1(d) , the polarizing plate 100 with a substrate having a predetermined size can be produced.

A-5. Fabrication of an image display device

In this embodiment, an image display apparatus can be obtained by using the polarizing plate with a board|substrate obtained as mentioned above as a display cell board|substrate. In the case of manufacturing a liquid crystal display device, as an example, the following procedure can be employed: (1) preparing a pair of polarizing plates with a substrate; (2) a switching element (eg, TFT) is provided on the substrate surface of one polarizing plate with a substrate, and a color filter is provided on the substrate surface of the other polarizing plate with a substrate; (3) forming an alignment film on the surface of each substrate and subjecting the alignment film to an alignment treatment; (4) bonding the polarizing plates with a substrate through a spacer so that each board|substrate opposes (a polarizing plate is arrange|positioned on the outside); (5) The liquid crystal is sealed between the substrates. In this way, the image display apparatus can be manufactured.

A-6. another embodiment

Although the embodiment using a polarizing plate with a board|substrate as a display cell board|substrate was demonstrated so far, as above-mentioned, the manufacturing method of this invention produces a display cell, laminates|stacks a polarizing plate on the board|substrate of the said display cell, and, then, forms a sealing part By doing so, an image display device can be obtained. In this embodiment, as an example, the following sequence may be employed:

(a-1) preparing a pair of substrates; (a-2) providing a switching element (eg, TFT) on one substrate surface and providing a color filter on the other substrate surface; (a-3) forming an alignment film on the surface of each substrate and subjecting the alignment film to an alignment treatment; (a-4) bonding a board|substrate through a spacer; (a-5) manufacturing a display cell by encapsulating a liquid crystal between substrates;

(b) so that the display cell extends and protrudes from the outer periphery of the polarizing plate (preferably so that the display cell extends and protrudes from all four sides constituting the outer periphery of the polarizing plate), and a polarizing plate is placed on the outside of each substrate of the display cell laminated;

(c) forming an encapsulation portion covering the peripheral cross-section of the polarizing plate;

(d) The encapsulation part and the display cell edge part are cut off, leaving the extension-protruding part of a predetermined length from the peripheral edge of the polarizing plate.

In this way, the image display apparatus can be manufactured. In addition, the details of steps (b) to (d) are the same as described in items A-2 to A-4 above. In addition, a margin for cutting is secured so that the edge of the display cell does not have an adverse effect due to cutting.

It is apparent to those skilled in the art that the present invention is applicable to any laminated structure of a substrate and a polarizing plate in an image display device other than the embodiments described above. After reading this specification, those skilled in the art can apply lamination of a substrate and a polarizing plate, formation of an encapsulation portion, and cutting of the encapsulation portion and a substrate to any laminated structure of a substrate and a polarizing plate in an image display device.

B. Image display device

The image display apparatus of this invention is obtained by the manufacturing method as described in said A item. Accordingly, the image display device typically has a structure as shown in Fig. 1(d). Specifically, the image display device has a polarizing plate and a substrate having an extending-projecting portion of a predetermined length from the peripheral edge of the polarizing plate, and an encapsulation portion formed in the extending-projecting portion and covering the peripheral end face of the corresponding polarizing plate.

The image display device preferably loses color after holding for 120 hours under 85°C and 85% RH environment, preferably 100 µm or less, more preferably 50 µm or less, still more preferably 30 µm or less, particularly preferably is 25 μm or less. The lower limit of the amount of discoloration is preferably 0, and in one embodiment is 5 μm. The amount of color loss is the amount of color loss at the end when an image display device replacement product (actually a polarizing plate with a substrate) is left in an oven at 85°C and 85% RH for 120 hours to humidify, and then placed in the state of a standard polarizing plate and cross nicol The condition is examined under a microscope. Specifically, the size (amount of color loss: μm) of color loss from the end of the polarizing plate or polarizing film is measured. As shown in Fig. 2 , the larger one is set as the color loss amount among the color loss amount (a) from the end portion in the stretching direction and the color loss amount (b) from the end portion in the direction orthogonal to the stretching direction. In addition, the color-fading region has remarkably low polarization characteristics, and does not substantially function as a polarizing plate. Therefore, the smaller the amount of color loss, the more preferable.

[Example]

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, the measuring method of each characteristic is as follows.

(1) thickness

Measurement was made using a digital micrometer (KC-351C manufactured by Anritsu Corporation).

(2) moisture permeability

By using the pressure-sensitive adhesive compositions prepared in Examples and Comparative Examples, pressure-sensitive adhesive sheets having the structure of release liner/adhesive layer (having the thickness of Example or Comparative Example)/release liner were formed. One side of the release liner of the pressure-sensitive adhesive sheet was peeled to expose the pressure-sensitive adhesive surface, and the pressure-sensitive adhesive sheet was bonded to a triacetyl cellulose film (TAC film, thickness: 25 µm, manufactured by Konica Minolta Co., Ltd.) with the pressure-sensitive adhesive surface interposed therebetween, and 10 cm Φ was cut to the original shape of Finally, the other release liner was peeled off to obtain a measurement sample. With respect to the obtained sample for measurement, the water vapor transmission rate (water vapor transmittance) was measured by the water vapor transmission rate test method (cup method, according to JIS Z 0208). In addition, the measurement conditions were as follows. In addition, at the time of measurement, a thermo-hygrostat was used.

Measuring temperature: 40℃

Relative Humidity: 92%

Measurement time: 24 hours

(3) Amount of color loss

The end of the polarizing film when the polarizing plate with a substrate obtained in Examples and Comparative Examples was left in an oven at 85° C. and 85% RH for 120 hours to be humidified as a replacement for an image display device, and then placed in a state of cross nicol with a standard polarizing plate was investigated under a microscope. Specifically, the size of color loss from the end of the polarizing film (amount of color loss: μm) was measured. MX61L manufactured by Olympus was used as a microscope, and the amount of color loss was measured in an image photographed at a magnification of 10 times. As shown in FIG. 2, the larger one was made into the color loss amount among the color loss amount (a) from the edge part in an extending|stretching direction and the color loss amount (b) from the edge part in a direction orthogonal to an extending|stretching direction.

[Example 1]

As a resin substrate, an amorphous polyethylene terephthalate (IPA copolymerized PET) film having a thickness of 100 μm and a Tg of 75° C. of 7 mol% of isophthalic acid units was prepared. Corona treatment (55 W/m ² /min) was applied to the surface of this film.

A PVA-based resin comprising acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industries, Ltd., trade name: Gosepimer (registered trademark) Z200) and PVA (average degree of polymerization: 4200, degree of saponification: 99.2 mol%) in a ratio of 1:9 was prepared, and 13 parts by weight of potassium iodide was added with respect to 100 parts by weight of the PVA-based resin to prepare an aqueous PVA-based resin solution (PVA-based resin concentration: 5.5% by weight). This aqueous solution is applied to the corona-treated surface of the resin substrate so that the film thickness after drying is 13 µm, dried by hot air drying in an atmosphere of 60°C for 10 minutes, and a PVA-based resin layer having a thickness of 9 µm is formed on the resin substrate did In this way, a laminate was produced.

The resulting laminate was stretched 2.4 times in air at 120°C (air-assisted stretching).

Next, the laminate was immersed in a boric acid aqueous solution having a liquid temperature of 40°C for 30 seconds to insolubilize the PVA-based resin layer. The boric acid aqueous solution of this process made the boric acid content 4 weight part with respect to 100 weight part of water.

Next, the laminate was immersed and dyed in a dye solution containing iodine and potassium iodide having a liquid temperature of 30°C for an arbitrary time so that the single transmittance of the resulting polarizing film was about 42 to 45%. In the dyeing solution, water was used as a solvent, the iodine concentration was within the range of 0.1 to 0.4% by weight, the potassium iodide concentration was within the range of 0.7 to 2.8% by weight, and the ratio of the concentration of iodine to potassium iodide was 1:7. .

Next, the laminated body was immersed in 40 degreeC boric-acid aqueous solution for 60 second, and the PVA resin layer to which iodine was adsorbed was crosslinked. In the aqueous boric acid solution in this step, the boric acid content was 5 parts by weight based on 100 parts by weight of water, and the potassium iodide content was 3 parts by weight based on 100 parts by weight of water.

Further, the laminate was stretched at a stretching temperature of 70°C in an aqueous boric acid solution, and stretched 2.3 times in the same direction as the previous aerial auxiliary stretching (final draw ratio 5.50 times). In the aqueous boric acid solution in this step, the boric acid content was 3.5 parts by weight based on 100 parts by weight of water, and the potassium iodide content was 5 parts by weight based on 100 parts by weight of water.

Next, the layered product was washed with an aqueous solution having a potassium iodide content of 4 parts by weight with respect to 100 parts by weight of water, dried with warm air at 60° C., and a polarizing film having a thickness of 5 μm was obtained on the resin substrate.

On the surface (surface on the opposite side to the resin substrate) of the obtained polarizing film, a cycloolefin-type film (the Nippon Zeon company make, ZF-12, 23 micrometers) was pasted through UV curable adhesive agent. Specifically, a UV curable adhesive was coated on each of a polarizing film and a cycloolefin type film so that it might become 1.0 micrometer in total thickness, and it was bonded together using the roll machine. Thereafter, ultraviolet rays were irradiated from the cycloolefin-based film side to cure the curable adhesive. Next, the resin substrate is peeled off, and the λ/4 plate (Nippon Zeon Co., Ltd., ZD-12, thickness 23 µm, Re (550) = 140 nm) of the cycloolefin film is bonded to the release surface via a curable adhesive. The polarizing plate which has the structure of , cycloolefin type film ZD-12 (protective film) / polarizing film / cycloolefin type film ZF-12 (protective film) was obtained. Further, the ZD-12 film was bonded so that its slow axis formed an angle of 45° with respect to the absorption axis of the polarizing film. This polarizing plate can be used, for example, as a viewing-side polarizing plate (anti-reflection film) of a reflection type liquid crystal display device or an organic EL display device.

The polarizing plate obtained above was cut to a size of 90 mm x 40 mm such that the absorption axis direction of the polarizing film was the long side direction. On the other hand, as a substrate, a commercially available glass plate (manufactured by Matsunami Glass Co., Ltd., thickness 0.4 mm) was cut out to a size of 110 mm x 60 mm. The cut-out polarizing plate and the cut-out board|substrate were laminated|stacked through the acrylic adhesive. Here, the polarizing plate and the substrate were laminated so that the ZD-12 film (λ/4 plate) of the polarizing plate was disposed on the substrate side. In addition, the polarizing plate and the substrate were laminated so that the substrate extends and protrudes from all four sides constituting the outer periphery of the polarizing plate. The length of the four elongated-projecting portions of the substrate was 10 mm each.

An adhesive was placed on the extended-projection portion, and the peripheral end face of the polarizing plate was sealed. In this way, the sealing part which covers the peripheral end surface of a polarizing plate was formed. In addition, the pressure-sensitive adhesive constituting the sealing part is polybutene (JX Nikko Niseki) based on 100 parts by weight of a block copolymer of styrene/ethylene propylene copolymer/styrene (manufactured by Kuraray, trade name 'Septon 2063', styrene content: 13 wt%) Energy Co., Ltd., trade name 'Niseki Polybutene HV-300') 10 parts by weight, terpene phenol tackifier (Yasuhara Chemical Co., Ltd. trade name 'YS Polystar TH130') 40 parts by weight and aromatic tackifier (Eastman Chemical) manufactured by Co., Ltd., trade name 'Picolastic A5').

Next, the pressure-sensitive adhesive and the substrate were irradiated with laser light, leaving 100 µm at the peripheral edge of the polarizing plate, and the pressure-sensitive adhesive was cut to form a final sealing portion. The water vapor transmission rate of the obtained sealing part was 12 g/m<2>/24hr. Laser light irradiation was performed using 'LaserPro Spirit' manufactured by GCC.

A polarizing plate with a substrate was produced as described above. The obtained polarizing plate with a board|substrate was used for evaluation of color loss as described in said (3). A result is shown in Table 1. In addition, the state of color loss is shown in FIG.

[Example 2]

A cycloolefin-based film (manufactured by Nippon Zeon, ZF-12, 13 µm) was pasted together in the same manner as in Example 1 on the surface of the polarizing film of the laminate of the resin substrate/polarizing film obtained in the same manner as in Example 1. Next, the resin substrate is peeled, and a reflective polarizer (manufactured by 3M, APF-V3) is bonded to the peeling surface via an adhesive (12 µm), and a cycloolefin-based film ZF-12 (protective film)/polarizing film/ A polarizing plate having a configuration of a reflection type polarizer was obtained. Further, the reflective polarizer was bonded so that the transmission axis thereof and the transmission axis of the polarizing film formed an angle of 0°. This polarizing plate can be used, for example, as a back-side polarizing plate.

The following procedure carried out similarly to Example 1, and produced the polarizing plate with a board|substrate. In addition, the polarizing plate and the substrate were laminated so that the ZF-12 film (protective film) of the polarizing plate was disposed on the substrate side. The obtained polarizing plate with a board|substrate was used for evaluation similar to Example 1. A result is shown in Table 1.

[Example 3]

A cycloolefin-based film (manufactured by Nippon Zeon, ZF-12, 13 µm) was pasted together in the same manner as in Example 1 on the surface of the polarizing film of the laminate of the resin substrate/polarizing film obtained in the same manner as in Example 1. Next, the resin base material was peeled, and the polarizing plate which has the structure of cycloolefin type film ZF-12 (protective film)/polarizing film was obtained. The following procedure carried out similarly to Example 1, and produced the polarizing plate with a board|substrate. In addition, the polarizing plate and the substrate were laminated so that the polarizing film was disposed on the substrate side. The obtained polarizing plate with a board|substrate was used for evaluation similar to Example 1. A result is shown in Table 1.

[Example 4]

A polarizing plate with a substrate was produced in the same manner as in Example 1 except that a sealing portion (thickness of 50 µm) having a water vapor transmission rate of 24 g/m ^{2 /24hr was formed.} The obtained polarizing plate with a board|substrate was used for evaluation similar to Example 1. A result is shown in Table 1.

[Example 5]

A polarizing plate with a substrate was produced in the same manner as in Example 2 except that a sealing portion (thickness of 50 µm) having a water vapor transmission rate of 24 g/m ^{2 /24hr was formed.} The obtained polarizing plate with a board|substrate was used for evaluation similar to Example 1. A result is shown in Table 1.

[Example 6]

A polarizing plate with a substrate was produced in the same manner as in Example 3 except that a sealing portion (thickness of 50 µm) having a water vapor transmission rate of 24 g/m ^{2 /24hr was formed.} The obtained polarizing plate with a board|substrate was used for evaluation similar to Example 1. A result is shown in Table 1.

[Comparative Example 1]

Except not having formed the sealing part, it carried out similarly to Example 1, and produced the polarizing plate with a board|substrate. The obtained polarizing plate with a board|substrate was used for evaluation similar to Example 1. A result is shown in Table 1. In addition, the state of color loss is shown in FIG.

[Comparative Example 2]

^{A sealing portion (water vapor transmission rate: more than 1000 g/m 2} /24 hr, thickness: 25 μm) was formed in the same manner as in Example 1 except that a conventional acrylic pressure-sensitive adhesive was used, and a polarizing plate with a substrate was produced. The obtained polarizing plate with a board|substrate was used for evaluation similar to Example 1. A result is shown in Table 1.

[Table 1]

As is clear from Table 1, it can be seen that a polarizing plate with a substrate (finally an image display device) capable of maintaining excellent optical properties even in a humidified environment is obtained by forming a sealing portion having a predetermined moisture permeability on the outer peripheral end face of the polarizing plate.

For the image display device obtained by the manufacturing method of the present invention, a TV, a display, a mobile phone, a portable information terminal, a digital camera, a camcorder, a portable game machine, a car navigation system, a copier, a printer, a fax machine, a watch, a microwave oven, etc. are preferably used. .

10 Polarizer
20 board
30 bags
40 encapsulation (final)
100 Polarizing plate with substrate

Claims (9)

Preparing a polarizing plate and a substrate having a larger size than the polarizing plate,
stacking the substrate and the polarizing plate so that the substrate extends from the outer periphery of the polarizing plate and protrudes;
forming an encapsulation unit covering the peripheral cross-section of the polarizing plate; and
Cutting the substrate and the encapsulation portion to a predetermined size leaving a portion extending-protruding a predetermined length from the peripheral edge of the polarizing plate
including,
wherein the substrate is a display cell substrate of an image display device selected from a liquid crystal display device, an organic EL display device, and a quantum dot display device
A method of manufacturing an image display device. According to claim 1,
The manufacturing method, wherein the substrate is a glass plate. According to claim 1,
The manufacturing method, wherein the substrate is a resin film. 4. The method according to any one of claims 1 to 3,
A manufacturing method in which the substrate and the polarizing plate are laminated such that the substrate extends and protrudes from all four sides constituting the outer periphery of the polarizing plate. 4. The method according to any one of claims 1 to 3,
wherein the cutting is performed by irradiating laser light. 4. The method according to any one of claims 1 to 3,
The manufacturing method of claim 1, wherein the length of the extended-projecting portion of the encapsulation portion after the cutting is 10 μm to 500 μm. 4. The method according to any one of claims 1 to 3,
The moisture permeability of the sealing part after the cutting is 300g/m ² /24hr or less, the manufacturing method.
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