TW201905508A - Manufacturing method for image display device, and image display device obtained according to said manufacturing method - Google Patents

Abstract

The invention provides a simple manufacturing method of a polarizing plate with a substrate that can maintain excellent optical characteristics and prevent fading in a humidified environment. The manufacturing method of the substrate-attached polarizing plate of the present invention includes the following steps: preparing a polarizing plate and a substrate having a larger size than the polarizing plate; laminating the substrate and the polarizing plate in such a manner that the substrate protrudes from the outer periphery of the polarizing plate; and forming a cover around the polarizing plate The sealing portion on the end surface; and the substrate and the sealing portion are cut out to retain a projecting portion of a predetermined length from the peripheral end of the polarizing plate to a predetermined size.

Description

Method for manufacturing image display device and image display device manufactured by the method

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

BACKGROUND OF THE INVENTION In an image display device (for example, a liquid crystal display device, an organic EL display device, or a quantum dot display device), due to its image formation method, a polarizing plate is usually arranged on at least one side of a display unit. However, the polarizing plate has a problem that the optical characteristics of the polarizing film, which can substantially determine the optical characteristics of the polarizing plate, have reduced durability under a humidified environment. More specifically, in a humidified environment, the polarization performance at the ends of the polarizing film will disappear, and as a result, the so-called fading phenomenon may occur in the image display device.

Prior Art Literature Patent Literature Patent Literature 1: Japanese Patent Laid-Open No. 2000-338329

SUMMARY OF THE INVENTION Problems to be Solved by the Invention 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 characteristics and preventing discoloration in a humidified environment and a simple manufacturing method thereof.

Means for solving the problem The manufacturing method of the image display device of the present invention includes the following steps: preparing a polarizing plate and a substrate larger in size than the polarizing plate; and laminating the substrate and the substrate in such a manner that the substrate protrudes from the outer periphery of the polarizing plate. A polarizing plate; forming a sealing portion covering a peripheral end surface of the polarizing plate; and cutting the substrate and the sealing portion to a predetermined size after retaining a protruding portion of a predetermined length from the peripheral end 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, the manufacturing method is such that the substrate and the polarizing plate are laminated in such a manner that the substrate protrudes from all four sides constituting the outer periphery of the polarizing plate. In one embodiment, the substrate is a display unit 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 protruding portion of the sealing portion after the cutting is 10 μm to 500 μm. In one embodiment, the moisture permeability of the sealed portion after the cutting is 300 g / m ² / 24hr or less. According to another aspect of the present invention, an image display device can be provided. The image display device includes: a polarizing plate; a substrate having a projecting portion having a predetermined length from a peripheral end of the polarizing plate; and a sealing portion formed on the projecting portion and covering a peripheral end surface of the polarizing plate.

ADVANTAGE OF THE INVENTION According to this invention, in the manufacturing method of an image display device, the sealing part is formed in the part which protrudes from a polarizing plate of a board | substrate, seals the peripheral end surface of a polarizing plate, and the sealing part and the corresponding protruding part of a board | substrate are retained from the The surrounding end of the polarizing plate is cut out after a predetermined length, thereby making it possible to easily manufacture an image display device that can maintain excellent optical characteristics and prevent fading in a humidified environment.

Embodiments for Implementing the Invention Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

A. Manufacturing method of image display device The manufacturing method of image display device of the present invention includes the following steps: preparing a polarizing plate and a substrate larger in size than the polarizing plate; and laminating the substrate in such a manner that the substrate protrudes from the outer periphery of the polarizing plate. And the polarizing plate; forming a sealing portion covering the peripheral end face of the polarizing plate; and cutting the substrate and the sealing portion to a predetermined size after retaining a protruding portion of a predetermined length from the peripheral end of the polarizing plate.

The invention can be applied to any laminated structure of a substrate and a polarizing plate of an image display device. The substrate is representatively a display unit substrate of an image display device. Representative examples of the image display device include a liquid crystal display device, an organic EL display device, and a quantum dot display device. Examples of the display unit substrate include a substrate of a liquid crystal cell, a substrate of an organic EL unit, a substrate of a quantum dot display unit, and a substrate in which a color filter is sealed on both sides of a liquid crystal display device. In one embodiment of the manufacturing method of the present invention, a substrate with a polarizing plate is laminated, and a sealing portion is formed in the laminated body to prepare a polarizing plate with a substrate, and then the polarizing plate with the substrate is used as a display unit substrate. Thereby, an image display device can be obtained. In another embodiment of the manufacturing method of the present invention, a display unit is manufactured, a polarizing plate is laminated on a substrate of the display unit, and then a sealing portion is formed, thereby obtaining an image display device. Hereinafter, as a representative example, an embodiment in which a polarizing plate with a substrate is used as a display unit substrate will be described.

A-1. Preparation of polarizing plate and substrate First, a polarizing plate 10 and a substrate 20 are prepared as shown in FIG. 1 (a). The polarizing plate and the substrate will be specifically described below.

A-1-1. Polarizing plate A 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 made of a film of a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") containing iodine. When the polarizing film contains iodine, the effect of providing a sealing portion becomes remarkable. The thickness of the polarizing film is typically 8 μm or less. When the polarizing film contains iodine and its thickness is quite thin as described above, the density of the iodine in the polarizing film will become higher, and the stability of iodine will be easily reduced by humidification, so the effect of providing the sealing portion will become more Significant. The protective film may be arranged on one side of the polarizing film or on both sides. When the protective film is disposed on one side of the polarizing film, it may be disposed on the display unit side or on the opposite side to the display unit. In practice, an adhesive layer is set as the outermost layer on the display unit side of the polarizing plate, and the polarizing plate is attached to the display unit by the adhesive layer. In addition, when only a protective film is referred to in this specification, it means that a film (a constituent element of a polarizing plate) for protecting the polarizing film is different from the surface protective film (a film that temporarily protects a polarizing plate during operation).

A-1-1-1. Polarizing film The polarizing film is composed of an iodine-containing PVA resin film as described above. The polarizing film may be formed of a single-layer resin film or a laminated body of two or more layers.

Specific examples of the polarizing film formed of a single-layer resin film include a polyvinyl alcohol (PVA) film, a partially formalized PVA film, and ethylene / vinyl acetate using a dichroic substance such as iodine or a dichroic dye. Ester copolymers are partially dyed and extended by hydrophilic polymer films such as saponified films, and polyene-based alignment films such as PVA dehydrated products or polyvinyl chloride dehydrochlorinated products. From the viewpoint of excellent optical characteristics, it is preferable to use a polarizing film obtained by dyeing a PVA-based film with iodine and uniaxially stretching it. The above dyeing with iodine can be performed, for example, by immersing a PVA-based film in an iodine aqueous solution. The stretching ratio of the above uniaxial stretching is preferably 3 to 7 times. The elongation may be performed after the dyeing treatment or at the same time as the dyeing. It can also be dyed after stretching. Swelling treatment, cross-linking treatment, washing treatment, drying treatment, etc. can be applied to PVA-based films according to demand. For example, immersing a PVA-based film in water and washing it before dyeing can not only remove dirt or anti-adhesive agent on the surface of the PVA-based film, but also swell the PVA-based film, thereby preventing uneven dyeing.

Specific examples of the polarizing film obtained by using a laminate include 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 coating A polarizing film obtained by laminating a PVA-based resin layer on the resin substrate. A polarizing film obtained by using a resin substrate and a laminate of a PVA-based resin layer formed on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and Forming a PVA-based resin layer on the resin substrate by drying to obtain a laminate of the resin substrate and the PVA-based resin layer; and extending and dyeing the laminate to form a PVA-based resin layer as a polarizing film. In the present embodiment, stretching means that the laminated body is immersed in an aqueous boric acid solution to perform stretching. In addition, if necessary, the stretching may further include performing air stretching at a high temperature (for example, 95 ° C. or higher) before performing the stretching in a boric acid aqueous solution. The obtained resin substrate / polarizing film laminate can be directly used (that is, the resin substrate can be used as a protective film for polarizing films), or the resin substrate can be peeled from the resin substrate / polarizing film laminate and applied to the peeling surface. Depending on the purpose, an optional and appropriate protective film is later used. Details of the method for producing the polarizing film are described in, for example, Japanese Patent Laid-Open No. 2012-73580. The entire description of the publication is referred to in this specification as a reference.

The PVA-based resin used to form the PVA-based resin film may be any appropriate resin. Examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer can be obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of PVA resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.9 mol%, and more preferably 99.0 mol% to 99.5 mol%. The degree of saponification is determined in accordance with JIS K 6726-1994. By using the PVA-based resin having the saponification degree, a polarizing film having excellent durability can be obtained. When the saponification degree is too high, there is a risk of gelation.

The average degree of polymerization of the PVA-based resin can be appropriately selected according to the purpose. The average degree of polymerization is usually 1000 to 10,000, preferably 1200 to 5000, and more preferably 1500 to 4500. The average degree of polymerization can be obtained in accordance with JIS K 6726-1994.

As described above, the polarizing film contains iodine. The polarizing film is essentially a PVA-based resin film in which iodine is aligned by adsorption. The iodine concentration in the PVA-based resin film is, for example, 5.0% by weight to 12.0% by weight. The boric acid concentration in the PVA-based resin film is, for example, 12 to 25% by weight.

As described above, the thickness of the polarizing film is 8 μm or less, preferably 7 μm or less, and more preferably 6 μm or less. 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 is suitable to exhibit absorption dichroism at any wavelength from 380nm to 780nm. The single transmittance of the polarizing film is preferably 40.0% to 46.0%, and 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 more preferably 99.98% or more. When a 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 more preferably 95% or more. As will be described later, by providing a sealing portion covering the end surface around the periphery of the image display panel containing the polarizing film, it is possible to have both the excellent optical characteristics (the balance between the single transmittance and the polarization degree) and excellent durability (even in The excellent optical characteristics are maintained in a wet environment).

A-1-1-2. Protective film The protective film is composed of an arbitrary and appropriate film that can be used as a protective film for a polarizing film. Specific examples of the material of the main component of the film include cellulose resins such as triethylammonium cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, and polyfluorene. Transparent resins such as imine, polyether fluorene, polyfluorene, polystyrene, polynorbornene, polyolefin, (meth) acrylic and acetate. In addition, thermosetting resins such as (meth) acrylic, urethane, urethane, (meth) acrylic, epoxy, and polysiloxane, and ultraviolet curable resins can also be mentioned. Other examples include glassy polymers such as siloxane polymers. In addition, a polymer film described in Japanese Patent Laid-Open No. 2001-343529 (WO01 / 37007) may be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted fluorene imine 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. In addition, for example, a resin composition having an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer can be cited. The polymer film may be, for example, an extruded shape of the resin composition.

In the embodiment of the present invention, as described above, the resin substrate used in manufacturing the polarizing plate may be directly used as a protective film.

In the 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 also be subjected to surface treatments such as hard coating treatment, anti-reflection treatment, anti-adhesion treatment, and anti-glare treatment as required.

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

When a protective film (inner protective film) is disposed on the display unit side of the polarizing film, in one embodiment, the inner protective film 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. The Re (550) of the inner protective film is preferably 0 nm to 8 nm, preferably 0 nm to 6 nm, and more preferably 0 nm to 3 nm. The Rth (550) of the inner protective film is preferably -8nm ~ + 8nm, more preferably -6nm ~ + 6nm, more preferably -3nm ~ + 3nm. In addition, "Re (550)" is an in-plane phase difference measured with light having a wavelength of 550 nm at 23 ° C. Re (550) can be obtained by using the formula: Re = (nx-ny) × d when the thickness of the layer (thin film) is d (nm). In addition, "Rth (550)" is a phase difference in the thickness direction measured at 23 ° C with light having a wavelength of 550 nm. Rth (λ) can be obtained by using the formula: Rth = (nx-nz) × d when the thickness of the layer (thin film) is d (nm).

In another embodiment, the inner protective film may have Re (550) which can function as a so-called λ / 4 plate. This embodiment can be applied to, for example, a case where a polarizing plate functions as a circular polarizing plate and is used as an anti-reflection film of a reflective liquid crystal display device or an organic EL display device. At this time, Re (550) is preferably 120 nm to 160 nm, and more preferably about 140 nm. At this time, the inner protective film may be configured such that its slow axis is preferably formed at an angle of about 40 ° to 50 ° with respect to the absorption axis of the polarizing film, and more preferably at an angle of about 45 °.

A-1-2. Substrate The substrate can have any arbitrary structure. For example, the substrate may be a glass plate or a resin film. The size of the substrate is larger than that of the polarizing plate. When the substrate and the polarizing plate are laminated, the substrate preferably has a size that extends a predetermined length from the outer periphery of the polarizing plate, and more preferably has a size that extends from all four sides constituting the outer periphery of the polarizing plate.

Any suitable glass plate can be used as the glass plate. The glass constituting the glass plate is classified according to the composition, and examples thereof include soda lime glass, boric acid glass, aluminosilicate glass, and quartz glass. Examples of the classification based on the alkaline component include alkali-free glass and low-alkali glass. The content of the alkali metal component (for example, Na ₂ O, K ₂ O, Li ₂ O) of the glass is preferably 15% by weight or less, and more preferably 10% by weight or less.

The light transmittance of the glass plate at a wavelength of 550 nm should be more than 85%. The refractive index of the glass plate at a wavelength of 550nm should be 1.4 ~ 1.65. The density of the glass plate is preferably 2.3 g / cm ³ to 3.0 g / cm ³ , and more preferably 2.3 g / cm ³ to 2.7 g / cm ³ .

The thickness of the glass plate should be 0.1mm ~ 1.0mm, more preferably 0.2mm ~ 0.6mm.

As the glass plate, a commercially available glass plate can be used directly, or a commercially available glass plate can be ground to a desired thickness and used. Commercially available glass plates include, for example, "7059", "1737" or "EAGLE2000" manufactured by Corning Corporation, "AN100" manufactured by AGC, "NA-35" manufactured by NH Techno Glass, and "OA-10" manufactured by Nippon Electric Glass. "," D263 "or" AF45 "made by SCHOTT.

Any appropriate resin film can be used as the resin film. The resin film is typically a transparent resin film. Examples of the material constituting the resin film include polyimide and polyimide. These can be used alone or in combination.

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

A-2. Lamination of polarizing plate and substrate Next, the polarizing plate 10 and the substrate 20 are laminated as shown in Fig. 1 (a). The polarizing plate 10 and the substrate 20 are representatively laminated through an arbitrary and appropriate adhesive layer (not shown in the drawings). As shown in FIG. 1 (a), the lamination is performed by the substrate protruding from the outer periphery of the polarizing plate, and preferably by the substrate protruding from all four sides constituting the outer periphery of the polarizing plate.

If necessary, a surface protection film (not shown in the drawings) may be temporarily attached to the surface of the polarizing plate 10 on the side opposite to the substrate 20. Thereby, the polarizing plate can be appropriately protected during the formation of the sealing portion described later and the cutting of the sealing portion and the substrate. The surface protection film is peeled off when the polarizing plate (substantially an image display device) with a substrate is finally used. The peeling and removal of the surface protection film can be performed at an arbitrary and appropriate timing after the formation of the sealing portion and the cutting of the sealing portion and the substrate.

A-3. Formation of Sealing Portion Next, as shown in FIG. 1 (b), a sealing portion 30 is formed to cover the peripheral end surface of the polarizing plate 10. Covering the peripheral end surface of the polarizing plate with the sealing portion can maintain the optical characteristics of the polarizing plate (polarizing film) in a humidified environment, and as a result, the durability of the image display device can be improved. Therefore, the sealing portion should have a shielding function. In the present specification, “having a barrier function” means that the amount of oxygen and / or water vapor entering the polarizing film can be controlled to substantially isolate the polarizing film from the polarizing film and the like.

The sealing portion is formed by disposing the adhesive composition so as to cover the peripheral end surface of the polarizing plate. In one embodiment, the adhesive composition may be disposed (for example, coated or disposed with a sheet-shaped adhesive) on the protruding portion of the substrate to form a sealing portion. The sealing portion covers the peripheral end surface of the polarizing plate and only needs to seal the peripheral end surface, and there is no need to closely adhere to the peripheral end surface. In addition, the sealing portion only needs to cover the peripheral end surface of the polarizing plate. Therefore, it is possible to cover the peripheral end surface as well as the portion other than the peripheral end surface. For example, the sealing portion may cover the peripheral end surface as well as the surface (upper surface in the drawing) of the side of the polarizing plate facing away from the substrate. At this time, the surface may be covered as a whole or only a predetermined portion may be covered.

Examples of the adhesive composition include a rubber-based adhesive composition using a rubber-based polymer as a base polymer.

Examples of the rubber-based polymer include a conjugated diene polymer obtained by polymerizing one conjugated diene compound, a conjugated diene polymer obtained by polymerizing two or more conjugated diene compounds, and a conjugated diene. A conjugated diene copolymer obtained by copolymerizing an olefin compound and an aromatic vinyl compound, and a hydride thereof.

The conjugated diene compound is not particularly limited as long as it is a monomer having a conjugated diene that can be polymerized. 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, 1,3-heptadiene, 1,3-hexadiene. Among them, 1,3-butadiene and isoprene are preferred from the standpoint of industrial availability. The conjugated diene compounds may be used alone or in combination.

The aromatic vinyl compound is not particularly limited as long as it is a monomer having an aromatic vinyl structure that can be copolymerized with a conjugated diene compound. Specific examples of the aromatic vinyl compound include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, from the viewpoint of industrial ease of access, styrene is preferred. The aromatic vinyl compounds may be used alone or in combination.

The diene copolymer may be a random copolymer or a block copolymer. Further, a compound other than the conjugated diene compound and the aromatic vinyl compound may be copolymerized to obtain a diene-based copolymer.

The molar ratio of the conjugated diene compound and the aromatic vinyl compound to a conjugated diene copolymer obtained by copolymerizing a conjugated diene compound and an aromatic vinyl compound is preferably a conjugated diene compound / aromatic ethylene Basic compound = 10/90 ~ 90/10 (mole%).

Specific examples of such conjugated diene-based (co) polymers include butadiene rubber (BR), isoprene rubber (IR), styrene-butadiene copolymer (SBR), butadiene Ene-isoprene-styrene random copolymer, isoprene-styrene random copolymer, styrene-isoprene block copolymer (SIS), butadiene-styrene copolymer, Styrene-ethylene-butadiene block copolymer (SEBS), acrylonitrile-butadiene rubber (NBR). These can be used alone or in combination. Among these, an isoprene-styrene copolymer is preferable. It is also possible to apply such hydrides.

In addition to conjugated diene-based (co) polymers, rubber-based polymers can also use isobutylene (IB), styrene-isobutylene-styrene block copolymer (SIBS), and styrene-ethylene-propylene copolymer-benzene. Ethylene block copolymers and the like. The rubber-based polymer may be used alone or in combination.

The rubber-based polymer usable in the present invention preferably contains 50% by weight or more of the above conjugated diene-based (co) polymer in the entire rubber-based polymer, and preferably contains 70% by weight or more, and 80% by weight. The above is more preferable, and more than 90% by weight is particularly preferable. The upper limit of the content of the conjugated diene-based (co) polymer is not particularly limited, and may be 100% by weight (that is, a rubber-based polymer composed of only a conjugated diene-based (co) polymer).

As described above, the adhesive composition system contains a rubber-based polymer as a base polymer. The content of the rubber-based polymer in the adhesive composition is preferably 40% by weight or more, more preferably 50% by weight or more, and 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.

The adhesive composition may contain an arbitrary and appropriate additive in addition to the rubber-based polymer. Specific examples of the additive include a cross-linking agent (for example, polyisocyanate, epoxy compound, alkyl etherified melamine compound, etc.), and a tackifier (for example, rosin derivative resin, polyterpene resin, petroleum resin, and fat-soluble phenol resin). , Vinyl toluene resin, etc.), plasticizers, fillers (such as layered silicate, clay materials, etc.), antioxidants. The type, combination, and amount of additives to be added to the adhesive composition can be appropriately set according to the purpose. The additive content (total amount) in the adhesive composition is preferably 60% by weight or less, more preferably 50% by weight or less, and even more preferably 40% by weight or less.

The thickness of the sealing portion 30 formed in the above manner is preferably 30 μm to 1000 μm, and more preferably 50 μm to 500 μm. In this specification, the meaning of "thickness of the sealing portion" means the thickness in a direction extending outward from the peripheral end of the polarizing plate as long as there is no explicit description (that is, the thickness of the sealing portion corresponds to the length of the protruding portion of the substrate). ).

A-4. Cutting of the sealing portion and the substrate Next, as shown in FIG. 1 (c), the sealing portion 30 and the substrate 20 are cut after retaining a protruding portion of a predetermined length from the peripheral end of the polarizing plate. As a result, as shown in FIG. 1 (d), a sealing portion 40 having a predetermined thickness is formed. The thickness of the sealing portion 40 after cutting is preferably 10 μm to 500 μm, and more preferably 20 μm to 300 μm.

Cutting can be performed mechanically or by laser light.

Examples of the mechanical cutting include grinding and end milling.

Laser light should preferably contain light with a wavelength of at least 1500 nm. Laser light preferably contains light with a wavelength of 100pm ~ 1000nm, more preferably contains light with a wavelength of 400nm ~ 900nm, and more preferably contains light with a wavelength of 420nm ~ 680nm. In one embodiment, the laser light has a peak wavelength within the above range. With the laser light having the above-mentioned wavelength, good cutting can be performed throughout the vertical thickness direction of the sealing portion.

Lasers include solid lasers such as YAG lasers, YLF lasers, YVO4 lasers, titanium sapphire lasers, gas lasers including argon ion lasers, krypton ion lasers, fiber lasers, semiconductor lasers, dyes Laser. And solid lasers should be used.

The above-mentioned laser is preferably a short-pulse laser (a laser irradiating light having a pulse width of less than 1 nanosecond, such as a picosecond laser or a femtosecond laser). In order to suppress heat loss to the sealing portion, a pulse width of 500 picoseconds or less (for example, 10 picoseconds to 50 picoseconds) is particularly preferable. By suppressing heat loss, a flat, uniform and smooth cutting surface can be obtained.

The irradiation conditions of the laser light can be set to arbitrary and appropriate conditions. For example, when using solid laser (YVO4 laser), the pulse energy should be 10μJ ~ 150μJ, and more preferably 25μJ ~ 71μJ. The scanning speed should be 10mm / second ~ 10000mm / second, more preferably 100mm / second ~ 1000mm / second. The repeated frequency is, for example, 100 Hz to 12480 Hz. The scanning interval should be 10μm ~ 50μm. The beam shape of the laser light irradiation position can be appropriately set according to the purpose. The beam shape may be circular or linear, for example. Any mechanism may be adopted as the mechanism for setting the beam shape to a predetermined shape. For example, laser irradiation may be performed through a mask having a predetermined opening, or beam forming such as a diffractive optical element may be used. For example, when the beam shape is circular, the focal length (dot diameter) is preferably 50 μm to 60 μm. In addition, the input energy of the pulse laser should preferably be 20,000 μJ / mm ² to 100,000 μJ / mm ² , and more preferably 25000 μJ / mm ² to 75000 μJ / mm ² . The input energy E (μJ / mm ² ) can be obtained from the following formula. E = (e × M) / (V × p) e: Pulse energy (J) M: Repeat frequency (Hz) V: Scan speed (mm / s) p: Scan interval (mm)

The irradiation pattern (scanning pattern) of the laser light can be appropriately set according to the purpose. Laser light can be scanned linearly, S-shaped, vortex, or a combination of these.

The sealing portion 40 formed as described above has a barrier property, which means that it has a barrier property against moisture and gas (for example, oxygen). The water vapor transmission rate (moisture permeability) of the sealing part 40 under the conditions of 40 ° C and 90% RH is preferably 300 g / m ² / 24hr or less, preferably 100 g / m ² / 24hr or less, and 50 g / m ² / It is more preferably less than 24hr, particularly preferably less than 25g / m ² / 24hr. The lower limit of water vapor transmission rate is, for example, 0.01 g / m ² / 24hr, and it is preferable that the detection limit is not reached. As long as the moisture permeability of the sealing portion 40 is within the range described above, the image display panel can be well protected from contact with moisture and oxygen in the air. The moisture permeability can be measured in accordance with JIS Z0208.

Through the above procedure, as shown in FIG. 1 (d), a polarizing plate 100 with a substrate having a predetermined size can be manufactured.

A-5. Production of image display device In this embodiment, an image display device can be obtained by using a polarizing plate with a substrate obtained through the above procedure as a display unit substrate. To make a liquid crystal display device, the following procedures can be used as an example: (1) preparing a pair of polarizing plates with substrates; (2) setting a switching element (such as a TFT) on the substrate surface of one of the polarizing plates with substrates, A color filter is provided on the substrate surface of another polarizing plate with a substrate; (3) forming an alignment film on each substrate surface and performing alignment processing on the alignment film; (4) making each substrate face to face (The plate is disposed on the outside) and a polarizing plate attached to the substrate is bonded via a spacer; and (5) a liquid crystal is filled between the substrates. An image display device can be manufactured through the above procedures.

A-6. Other Embodiments So far, the embodiment in which a polarizing plate with a substrate is used as a display unit substrate has been described. However, as described above, the manufacturing method of the present invention can produce a display unit and laminate the polarizing plate on the display unit. A sealing portion is then formed on the substrate of the display unit to obtain an image display device. In this embodiment, as an example, the following procedures can be used: (a-1) preparing a pair of substrates; (a-2) providing a switching element (such as a TFT) on one substrate surface, and providing color on the other substrate surface Filters; (a-3) forming an alignment film on the surface of each substrate and performing alignment processing on the alignment film; (a-4) bonding the substrate through a spacer; and (a-5) filling the liquid crystal into the substrate (B) The display unit is protruded from the outer periphery of the polarizing plate (preferably the display unit is protruded from all four sides constituting the outer periphery of the polarizing plate), and the polarizing plates are laminated on the respective display units. The outer side of the substrate; (c) forming a sealing portion covering the peripheral end surface of the polarizing plate; and (d) cutting the sealing portion and the peripheral edge portion of the display unit after retaining a protruding portion of a predetermined length from the peripheral end of the polarizing plate. An image display device can be manufactured through the above procedures. The details of steps (b) to (d) are as described in the above items A-2 to A-4. In addition, the peripheral portion of the display unit has ensured that there is a blank space for cutting so as not to be adversely affected by cutting.

In addition to the embodiments described above, the present invention can also be applied to any laminated structure of a substrate and a polarizing plate of an image display device, and this point is self-evident to those skilled in the art. As long as this manual is read, those skilled in the art can apply the lamination of the substrate and the polarizing plate, the formation of the sealing portion and the cutting of the sealing portion and the substrate to any laminated structure of the substrate and the polarizing plate of the image display device.

B. Image display device The image display device of the present invention can be manufactured by the manufacturing method described in the above item A. Therefore, the image display device typically includes a structure as shown in FIG. 1 (d). Specifically, the image display device includes: a polarizing plate; a substrate having a protruding portion having a predetermined length from a peripheral end of the polarizing plate; and a sealing portion formed on the protruding portion and covering a peripheral end surface of the polarizing plate.

After the image display device is maintained at 85 ° C and 85% RH for 120 hours, the amount of discoloration should be 100 μm or less, more preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 25 μm or less. The lower limit of the amount of fading is preferably 0, and is 5 μm in one embodiment. The amount of fading is after placing the image display device replacement (substantially a polarizing plate with a substrate) in an oven at 85 ° C and 85% RH for 120 hours for humidification, and then placing it in a state of orthogonal polarization with a standard polarizing plate. Then, the discoloration state of the end part was observed with a microscope. Specifically, the amount of fading (amount of fading: μm) measured from the polarizing plate or from the end of the polarizing film was measured. As shown in FIG. 2, the larger the value of the discoloration amount a from the end portion in the extension direction and the discoloration amount b from the end portion which is orthogonal to the extension direction, the larger the value. In addition, the polarization characteristics of the faded area are significantly low, and the function as a polarizing plate cannot be practically implemented. Therefore, the smaller the amount of fading, the better. Examples

Hereinafter, the present invention will be specifically described with examples, but the present invention is not limited by these examples. The measurement method of each characteristic is as follows.

(1) Thickness was measured using a digital micrometer (KC-351C manufactured by Anritsu Corporation). (2) Moisture permeability Using the adhesive composition prepared in Examples and Comparative Examples, an adhesive sheet having a release liner / adhesive layer (having the thickness of the example or comparative example) / release liner was formed. Next, after peeling off one of the release liners of the adhesive sheet to expose the adhesive surface, the adhesive sheet was adhered to the triethyl cellulose film (TAC film, thickness: 25 μm, made by Konica Minolta) through the adhesive surface. And cut into a circular shape of 10 cmΦ. Finally, the other release liner is peeled off to obtain a measurement sample. The obtained sample for measurement was measured for water vapor transmission rate (water vapor transmission rate) by a water vapor transmission test method (cup method, in accordance with JIS Z 0208). The measurement conditions are as follows. A constant temperature and humidity tank was used for the measurement. Measurement temperature: 40 ° C Relative humidity: 92% Measurement time: 24 hours (3) Amount of discoloration The polarizing plate with a substrate prepared in the examples and comparative examples was placed at 85 ° C and 85% RH as a substitute for an image display device. After humidifying in the oven for 120 hours, the polarized film and the standard polarizing plate were placed in a state of orthogonal polarization, and then the discolored state of the end of the polarizing film was observed with a microscope. Specifically, the amount of discoloration (amount of discoloration: μm) from the end of the polarizing film was measured. The microscope used MX61L manufactured by Olympus, and the amount of fading was measured from an image taken at a magnification of 10 times. As shown in FIG. 2, the larger the value of the discoloration amount a from the end portion in the extension direction and the discoloration amount b from the end portion which is orthogonal to the extension direction, the larger the value.

[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. and an isophthalic acid unit was prepared. Corona treatment (55 W / m ² / min) was performed on the surface of the film. It is prepared to contain acetamidine modified PVA (manufactured by Japan Synthetic Chemical Industry Co., Ltd., trade name: GOHSEFIMER (registered trademark) Z200) and PVA (average degree of polymerization: 4200, saponification degree: 99.2 mole%) in a ratio of 1: 9 ), And 13 parts by weight of potassium iodide was added to 100 parts by weight of the PVA-based resin to prepare a PVA-based resin aqueous solution (PVA-based resin concentration: 5.5% by weight). The corona-treated surface of the resin substrate was coated with the aqueous solution so that the film thickness after drying became 13 μm, and dried with hot air in a gas environment of 60 ° C. for 10 minutes to form a 9 μm-thick PVA on the resin substrate Department of resin layer. The laminated body is made through the above procedure. The obtained laminated body was stretched 2.4 times at 120 ° C in the air (air-assisted extension). Next, the laminated body was immersed in a boric acid aqueous solution having a liquid temperature of 40 ° C. for 30 seconds to make the PVA-based resin layer insoluble. The boric acid aqueous solution in this step is 4 parts by weight with respect to 100 parts by weight of boric acid. Next, the laminated body is immersed in a dye solution containing iodine and potassium iodide at a liquid temperature of 30 ° C. for arbitrary time and dyed so that the monomer transmittance of the obtained polarizing film becomes about 42 to 45%. The dyeing solution uses water as a solvent, and the iodine concentration is within a range of 0.1 to 0.4% by weight, the potassium iodide concentration is within a range of 0.7 to 2.8% by weight, and the concentration ratio of iodine to potassium iodide is 1: 7. Next, the laminated body was immersed in a 40 ° C. boric acid aqueous solution for 60 seconds, and the PVA resin layer to which iodine was adsorbed was subjected to a crosslinking treatment. The boric acid aqueous solution in this step has a boric acid content of 5 parts by weight relative to 100 parts by weight of water, and a potassium iodide content of 3 parts by weight relative to 100 parts by weight of water. And, in a boric acid aqueous solution, the laminated body was extended at a stretching temperature of 70 ° C. in the same direction as the previous air-assisted stretching by 2.3 times (the final stretching ratio was 5.50 times). The boric acid aqueous solution in this step has a boric acid content of 3.5 parts by weight relative to 100 parts by weight of water, and a potassium iodide content of 5 parts by weight relative to 100 parts by weight of water. Next, the laminated body was washed with an aqueous solution having a potassium iodide content of 4 parts by weight relative to 100 parts by weight of water, and dried at a temperature of 60 ° C. to obtain a polarizing film having a thickness of 5 μm on a resin substrate.

A cycloolefin-based film (ZF-12, manufactured by Zeon Corporation, 23 μm) was bonded to the surface of the obtained polarizing film (surface on the side opposite to the resin substrate) through a UV-curable adhesive. Specifically, a UV-curable adhesive was applied to a polarizing film and a cycloolefin-based film to a total thickness of 1.0 μm, and was bonded using a roll mill. Thereafter, ultraviolet rays are irradiated from the cycloolefin-based film side to harden the hardening-type adhesive. Next, the resin substrate was peeled, and a λ / 4 plate (manufactured by ZEON, ZD-12, thickness 23 μm, Re (550) = 140 nm) of a cycloolefin-based film was bonded to the peeling surface by a hardening type adhesive. A polarizing plate having a structure of a cycloolefin-based film ZD-12 (protective film) / polarizing film / cycloolefin-based film ZF-12 (protective film) was obtained. In addition, the ZD-12 film is bonded so that its slow axis forms a 45 ° angle 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 reflective liquid crystal display device or an organic EL display device.

The polarizing plate prepared as described above was cut into a size of 90 mm × 40 mm so that the direction of the absorption axis of the polarizing film became the long side direction. On the other hand, a commercially available glass plate (manufactured by Matsunami Glass, thickness 0.4 mm) was cut into a size of 110 mm × 60 mm as a substrate. The cut out polarizing plate and the cut out substrate were laminated through an acrylic adhesive. The polarizing plate and the substrate here are laminated with a ZD-12 film (λ / 4 plate) of the polarizing plate disposed on the substrate side. The polarizing plate and the substrate are laminated so that all four sides of the outer periphery of the polarizing plate are formed by the substrate protruding. Each of the four protruding portions of the substrate has a length of 10 mm.

An adhesive is arranged on the protruding portion to seal the peripheral end surface of the polarizing plate. In this way, a sealing portion is formed to cover the peripheral end surfaces of the liquid crystal panel. In addition, the adhesive constituting the sealing portion is based on 100 parts by weight of a styrene-ethylene propylene copolymer-styrene block copolymer (manufactured by Kuraray, trade name "SEPTON 2063", styrene content: 13% by weight). ), 10 parts by weight of polybutene (produced by JX Nippon Nissei Energy Co., Ltd., "trade name" Nishiishi Polybutene HV-300 "), 40 parts by weight of terpene phenol tackifier (manufactured by YASUHARA CHEMICAL Corporation, product Named "YS Polyster TH130") and an aromatic tackifier (manufactured by Eastman Chemical, trade name "Piccolastic A5").

Next, the adhesive and the substrate were irradiated with laser light, and the adhesive was cut out after retaining 100 μm from the peripheral end of the polarizing plate to form a final sealing portion. The moisture permeability of the obtained sealed portion was 12 g / m ² / 24hr. Laser light was irradiated using "LaserPro Spirit" manufactured by GCC.

Through the above procedures, a polarizing plate with a substrate was fabricated. The obtained polarizing plate with a substrate was subjected to the fading evaluation described in (3) above. The results are shown in Table 1. In addition, a faded state is shown in FIG. 3.

[Example 2] A cycloolefin-based film (manufactured by Japan Zeon Corporation, ZF) was laminated on the surface of a polarizing film of a resin substrate / polarizing film laminate obtained in the same manner as in Example 1 in the same manner as in Example 1. -12, 13 μm). Next, the resin substrate was peeled off, and a reflective polarizer (manufactured by 3M, APF-V3) was bonded to the peeling surface with an adhesive (12 μm) to obtain a cycloolefin-based film ZF-12 (protective film) / A polarizing plate composed of a polarizing film and a reflective polarizer. The reflective polarizer is bonded so that its transmission axis and the transmission axis of the polarizing film form an angle of 0 °. This polarizing plate can be used as a back side polarizing plate, for example.

A polarizing plate with a substrate was fabricated in the same manner as in Example 1 below. The polarizing plate and the substrate are laminated with a ZF-12 film (protective film) of the polarizing plate disposed on the substrate side. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 3] A cycloolefin-based film (manufactured by Japan Zeon Corporation, ZF) was bonded to the surface of a polarizing film of a resin substrate / polarizing film laminate obtained in the same manner as in Example 1 in the same manner as in Example 1. -12, 13 μm). Next, the resin substrate was peeled off to obtain a polarizing plate having a configuration of a cycloolefin-based film ZF-12 (protective film) / polarizing film. A polarizing plate with a substrate was fabricated in the same manner as in Example 1 below. The polarizing plate and the substrate are laminated with a polarizing film disposed on the substrate side. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 4] The moisture permeability of the sealing portion is formed (thickness 50μm) 24g / m ² / 24hr, the addition of a polarizing plate attached to the substrate by making the same manner as in Example 1. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 5] The moisture permeability of the sealing portion is formed (thickness 50μm) 24g / m ² / 24hr, the production according to the same manner except that in Example 2 of a polarizing plate attached to the substrate. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 6] The moisture permeability of the sealing portion is formed (thickness 50μm) 24g / m ² / 24hr, the addition of a polarizing plate attached to the substrate by making the same manner as in Example 3. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Comparative Example 1] A polarizing plate with a substrate was produced in the same manner as in Example 1 except that the sealing portion was not formed. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1. The state of discoloration is shown in FIG. 4.

[Comparative Example 2] A sealing portion was formed in the same manner as in Example 1 except that a general acrylic adhesive was used (permeability: greater than 1000 g / m ² / 24hr, thickness: 25 μm), and a substrate was fabricated. Of polarizing plate. The obtained polarizing plate with a substrate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Table 1]

It is obvious from Table 1 that by forming a sealing portion with a predetermined moisture permeability on the outer peripheral end face of the polarizing plate, a polarizing plate with a substrate (the last is an image display device) that can maintain excellent optical characteristics in a humidified environment ).

Industrial Applicability The image display device produced by the manufacturing method of the present invention is suitable for use in televisions, displays, mobile phones, mobile information terminals, digital cameras, video cameras, portable game consoles, car navigation systems, and photocopying. Machines, printers, fax machines, clocks, microwave ovens, etc.

10‧‧‧ polarizing plate

20‧‧‧ substrate

30‧‧‧Sealing Department

40‧‧‧Sealing section (final)

100‧‧‧ polarizing plate with substrate

Brief Description of Drawings Fig. 1 is a schematic diagram for explaining a method for manufacturing an image display device according to an embodiment of the present invention. Fig. 2 is a schematic diagram for explaining calculation of the amount of discoloration. Fig. 3 is an image showing the amount of discoloration of a polarizing plate with a substrate as a substitute for the image display device of Example 1 after a humidification test. FIG. 4 is an image showing the amount of discoloration of a polarizing plate with a substrate as a substitute for the image display device of Comparative Example 1 after a humidification test.

Claims (9)

An image display device manufacturing method includes the following steps: preparing a polarizing plate and a substrate larger in size than the polarizing plate; laminating the substrate and the polarizing plate in such a manner that the substrate protrudes from the outer periphery of the polarizing plate; and forming a polarizing plate to cover the polarizing light A sealing portion on a peripheral end surface of the plate; and cutting the substrate and the sealing portion to a predetermined size after retaining a protruding portion of a predetermined length from the peripheral end of the polarizing plate. The method according to claim 1, wherein the substrate is a glass plate. The method according to claim 1, wherein the substrate is a resin film. According to the manufacturing method of any one of claims 1 to 3, the substrate and the polarizing plate are laminated in such a manner that the substrate protrudes to form all four sides of the outer periphery of the polarizing plate. The manufacturing method according to any one of claims 1 to 4, wherein the substrate is a display unit substrate of an image display device selected from a liquid crystal display device, an organic EL display device, and a quantum dot display device. The manufacturing method according to any one of claims 1 to 5, wherein the aforementioned cutting is performed by irradiating laser light. The manufacturing method according to any one of claims 1 to 6, wherein the length of the protruding portion of the sealing portion after the cutting is 10 μm to 500 μm. The manufacturing method according to any one of claims 1 to 7, wherein the moisture permeability of the sealed portion after the cutting is 300 g / m ² / 24hr or less. An image display device includes: a polarizing plate; a substrate having a protruding portion having a predetermined length from a peripheral end of the polarizing plate; and a sealing portion formed on the protruding portion and covering a peripheral end surface of the polarizing plate.