TW201430408A - Polarizing plate and image display device - Google Patents

Abstract

Disclosed is a polarizing plate using a polyester film as a polarizer protective film, wherein there hardly occurs separation at the interface between the polarizer and the protective film. Specifically disclosed is a polarizing plate wherein at least one polyester film (E), at least one major surface of which is provided with a highly adhesive layer (H), and a polarizer (P) are laminated in such a manner that the surface of the polyester film on which the highly adhesive layer is formed faces the polarizer through an adhesive layer (G). The polarizer (P) and the polyester film (E) are preferably laminated through an adhesive layer which is composed of a resin solution containing a polyvinyl alcohol resin, a crosslinking agent and a metal compound colloid having an average particle diameter of 1-100 nm. The metal compound colloid is contained in the adhesive layer in an amount of not more than 200 parts by weight per 100 parts by weight of the polyvinyl alcohol resin.

Description

Polarizer and image display device

The present invention relates to a polarizing plate in which a polarizing element and at least one film are laminated. Further, the present invention relates to an image display device using the polarizing plate. Further, the present invention relates to a method of manufacturing the image display device.

In the liquid crystal display device, in terms of the image forming method, it is indispensable to provide a polarizing plate on both sides of the glass substrate on which the surface of the liquid crystal panel is formed. The polarizing plate is usually used on both surfaces of a polarizing element including a polyvinyl alcohol-based film and a dichroic material such as iodine, and a polarizing element protective film such as cellulose triacetate is used in combination with a polyvinyl alcohol-based adhesive.

However, cellulose triacetate has the following disadvantages: its heat and humidity resistance is not sufficient, and when a cellulose triacetate film is used as a polarizing plate of a polarizing element protective film under high temperature or high humidity, a polarizing or color-equivalent polarizing plate is used. The performance is degraded.

In order to solve the above problems, a material in which a cyclic olefin resin is used instead of cellulose triacetate as a protective film for a polarizing element has been proposed. Since the cyclic olefin resin has low moisture permeability, the polarizing plate can have high durability. However, the polyvinyl alcohol-based adhesive is excellent in adhesion to the cellulose triacetate film and the polyvinyl alcohol-based polarizing element, but lacks adhesion to the cyclic olefin-based resin film and the polyvinyl alcohol-based polarizing element.

Therefore, as a method of arranging a cyclic olefin-based resin film and a polyvinyl alcohol-based polarizing element, a method of adhering via an acrylic pressure-sensitive adhesive layer has been proposed (see Patent Document 1). However, this method must be subjected to heat and pressure bonding, and the heating time is also long, so that the discoloration of the polyvinyl alcohol-based polarizing element may occur, resulting in a significant decrease in the polarizing degree of the polarizing plate. problem. Moreover, since heating is required for a long period of time, there is also a problem that the production efficiency is low and the film is deformed.

Further, a polyester film has been proposed as a protective film for a polarizing element (see Patent Documents 2 and 3). In addition, in order to solve the problem of adhesion or film strength, a method of coextruding a polyester with a styrene-based or olefin-based monomer, a nylon-based resin, or an acrylic resin has been disclosed (see Patent Documents 4 to 7).

Patent Document 1: Japanese Patent Laid-Open No. Hei 5-212828

Patent Document 2: Japanese Patent Laid-Open No. Hei 8-271733

Patent Document 3: Japanese Patent Laid-Open No. Hei 8-271734

Patent Document 4: Japanese Patent Laid-Open Publication No. 2006-215466

Patent Document 5: Japanese Patent Laid-Open Publication No. 2006-220731

Patent Document 6: Japanese Patent Laid-Open No. 2006-220732

Patent Document 7: Japanese Patent Laid-Open Publication No. 2006-276574

However, the adhesion between the polyester and the polarizing element or other resin layer is not sufficient, and in the case of the co-extrusion disclosed in Patent Documents 4 to 7, etc., it is also easy to exist at the interface between the polyester layer and the other resin layer. There are problems such as peeling.

In view of the above, the present invention provides a polarizing plate having a polyester layer which is excellent in adhesion and which is less likely to cause film peeling.

As a result of intensive studies by the inventors of the present application, it has been found that the above problems can be solved by a specific configuration, thereby achieving the present invention. That is, the present invention relates to a polarizing plate which is formed of at least one polyester film E and a polarizing element P on which at least one main surface is formed with an easy adhesion layer H, and an easy adhesion layer forming surface of the polyester film. The polarizing elements are laminated via the adhesive layer G in a relative manner.

Further, in the polarizing plate of the present invention, the adhesive layer G is preferably formed of the following adhesive: a polyvinyl alcohol-based resin, a crosslinking agent, and a metal compound having an average particle diameter of 1 to 100 nm. A colloidal resin solution is prepared, and the metal compound gum system is prepared in an amount of 200 parts by weight or less based on 100 parts by weight of the polyvinyl alcohol-based resin.

Further, in the polarizing plate of the present invention, the easy-adhesion layer H preferably contains a polyvinyl alcohol compound or a polyurethane compound.

In one embodiment of the polarizing plate, a polyester film E having an easy-adhesion layer H formed on at least one of the main surfaces is laminated on one of the main surfaces of the polarizing element P via the adhesive layer G. A polarizing plate in which no film is laminated on the other main surface of the polarizing element P.

Furthermore, the present invention relates to an image display device having the above polarizing plate.

Further, the present invention relates to a method of manufacturing the above image display device. An embodiment of the method of manufacturing an image display device of the present invention preferably includes a reel material preparation step of preparing a long sheet of the polarizing plate as a reel material, and a cutting step of the cutting step. The reel material pulls the sheet product, and the polarizing plate is cut into a predetermined size by using a cutting mechanism; and a bonding step of bonding the polarizing plate to the optical layer via the adhesive layer after the cutting step On the display unit.

1‧‧‧1st sheet product

2‧‧‧2nd sheet product

11‧‧‧1st optical film

12‧‧‧1st release film

14‧‧‧1st adhesive layer

21‧‧‧2nd optical film

22‧‧‧2nd release film

24‧‧‧2nd adhesive layer

A‧‧‧Optical display unit

E‧‧‧ polyester film

G‧‧‧ adhesive layer

H‧‧‧Easy layer

P‧‧‧ Polarized components

T‧‧‧Transparent film

W‧‧‧Optical display unit

1(a) to 1(c) are schematic cross-sectional views showing a polarizing plate of a preferred embodiment of the present invention.

Fig. 2 is a flow chart showing an example of a method of manufacturing the prior optical display unit.

Fig. 3 is a flow chart showing an example of a method of manufacturing the image display device of the present invention.

Fig. 4 is a flow chart showing an example of a method of manufacturing the image display device of the present invention.

Fig. 5A is a view for explaining an example of a configuration of a manufacturing system of an image display device.

Fig. 5B is a view for explaining an example of a configuration of a manufacturing system of the image display device.

The present invention relates to a polarizing plate in which at least one polyester film E on which an easy adhesion layer H is formed on at least one main surface and a polarizing element P are laminated via an adhesive layer G. Hereinafter, preferred embodiments of the polyester film E, the easy-adhesion layer H, the polarizing element P, and the adhesive layer G will be described in order.

[Polyester film]

The polyester film E is used as a protective film for a polarizing element. The material for forming the polyester film is not particularly limited, and examples thereof include terephthalic acid, isophthalic acid, phthalic acid, 2,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and 1, 4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, diphenylcarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl indenic acid, phthalic acid, 1,3-cyclopentane dicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3 -diethyl succinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipate, trimethyl adipate, pimelic acid, sebacic acid, a dicarboxylic acid such as dimer acid, sebacic acid, suberic acid or dodecane dicarboxylic acid, and ethylene glycol, propylene glycol, hexanediol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1, 4-cyclohexanedimethanol, decanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-bis(4- a homopolymer obtained by polycondensing one of diols such as hydroxyphenyl)propane and bis(4-hydroxyphenyl) hydrazine, or one or more dicarboxylic acids and two or more a copolymer obtained by polycondensation or a copolymer obtained by polycondensing two or more kinds of dicarboxylic acids with one or more kinds of diols, and two or more kinds of such homopolymers or copolymers Any of the blended resins may be a polyester resin. Among them, it is preferred to use a polyethylene terephthalate resin.

The polyester film can be obtained, for example, by a method in which the polyester resin is melt-extruded into a film shape, and cooled and solidified using a casting drum to form a film. As the polyester film E in the polarizing plate of the present invention, any of an unstretched film and a stretched film can be used. For example, in the case where a small birefringence is required, an unstretched film can be suitably used. Again, for using birefringence When the liquid crystal display device is optically compensated or the like, a stretched film can be suitably used. Further, the stretched film, particularly the biaxially stretched film, may be suitably used in view of strength.

When the polyester film E is a stretched film, the stretching method is not particularly limited, and a longitudinal uniaxial stretching method, a transverse uniaxial stretching method, a vertical and horizontal sequential biaxial stretching method, a vertical and horizontal simultaneous biaxial stretching method, or the like can be employed. As the extending mechanism, any suitable stretching machine such as a roll stretching machine, a tenter stretching machine, a zooming ceremony, or a linear motor type double-axis stretching machine can be used.

The thickness of the above polyester film E is preferably from 5 to 500 μm, more preferably from 5 to 200 μm, still more preferably from 10 to 150 μm. When the thickness is less than the above range, the film may be easily broken, the strength may be applied to the polarizing plate, or the moisture barrier property may be insufficient, resulting in poor durability of the polarizing element. When the thickness is larger than the above range, there is a case where the film lacks flexibility to deteriorate workability, or the polyester film itself becomes difficult to manufacture.

[easy layer]

In the polarizing plate of the present invention, the easy-adhesion layer H is formed on at least one main surface of the polyester film E. Examples of the easy-adhesion layer H include those formed by a hydrophilic cellulose derivative, a polyvinyl alcohol-based compound, a hydrophilic polyester-based compound, a polyethylene-based compound, a (meth)acrylic compound, and an epoxy resin. Resins, polyurethane compounds, natural polymer compounds, and the like.

Examples of the hydrophilic cellulose derivative include methyl cellulose, carboxymethyl cellulose, and hydroxy cellulose.

Examples of the polyvinyl alcohol-based compound include polyvinyl alcohol, vinyl acetate-vinyl alcohol copolymer, polyvinyl acetate, polyvinyl acetal, polyethylene formaldehyde, and polyethylene benzylidene. In particular, from the viewpoint of adhesion to the polyester film, it is preferred to formulate a crosslinking agent. Preferred crosslinking agents will be described later.

Examples of the hydrophilic polyester compound include sulfonated polyethylene terephthalate and the like.

Examples of the polyethylene-based compound include poly-N-vinylpyrrolidone and polypropylene oxime. Amine, polyvinylimidazole, polyvinylpyrazole, and the like.

Examples of the (meth)acrylic compound include acrylic acid, carboxyalkyl acrylate, alkyl acrylate, hydroxyalkyl acrylate, hydroxyalkyl acrylate, methacrylic acid, carboxyalkyl methacrylate, and A. Alkyl acrylate, hydroxyalkyl methacrylate, hydroxyalkyl methacrylate, and the like.

Examples of the epoxy resin include aromatic epoxies such as bisphenol epoxy resins, novolac epoxy resins, and epoxidized polyvinyl phenols, and hydrogenated aromatic epoxy resins and cyclohexane rings. An alicyclic epoxy resin such as an oxygen resin or a cyclohexyl methyl ether epoxy resin, an aliphatic epoxy such as a polyalkylene oxide glycidyl ether, a polyether polyol glycidyl ether or a polyether polyol glycidyl ether. Resin type.

Examples of the polyurethane resin include a polyhydric alcohol such as an acrylic polyol, a polyester polyol, or a polyether polyol, and a reaction product of a polyisocyanate such as tetramethylene diisocyanate or isophorone diisocyanate. . Among them, a polyester-based polyurethane is suitably used from the viewpoint of adhesion to a polyester film.

Examples of the natural polymer compound include gelatin, casein, gum arabic, and the like.

Among the above, a polyvinyl alcohol derivative or a polyurethane compound can be suitably used from the viewpoint of adhesion.

Further, the easy-adhesion layer H may contain a crosslinking agent. In particular, when the adhesion layer is mainly a lower adhesion (adhesion) to a polyester film such as a polyvinyl alcohol compound or a polyethylene compound, the easy adhesion layer H preferably contains Crosslinker. Examples of the crosslinking agent include crosslinking agents such as acrylic, styrene, epoxy, phenol, phenoxy ether, phenoxy ester, melamine, and urethane. Among them, in terms of improving the adhesion between the polyester and the easy-to-attach layer, it is suitable to have A crosslinking agent of an oxazoline group, a diimenimine group, a fluorenyl group, or an epoxy group.

The easy-adhesion layer H is preferably formed by forming the above compound into a solution, a dispersion or an emulsion and applying it on a polyester film. When coating, prevent environmental pollution and obtain explosion-proof From the viewpoint of properties, it is preferred to use it as an aqueous coating liquid. Further, from the viewpoint of promoting the wet coating of the aqueous coating liquid or the stability of the coating liquid, the surfactant may be formulated. The appropriate amount of the surfactant to be added to the coating liquid varies depending on the kind of the surfactant, and the amount can be appropriately adjusted so that the easy-contact layer H and the polarizing element have sufficient adhesion. For example, it may contain about 1 to 10 parts of surfactant, based on 100 parts by weight of the solid content of the aqueous coating liquid.

The surfactant may be any of anionic, cationic or nonionic, such as polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, fatty acid glyceride, fatty acid metal soap, alkyl sulfate, alkane. A sulfonate, an alkyl sulfosuccinate, a quaternary ammonium chloride, an alkylamine hydrochloride, a betaine type surfactant, and the like.

An antistatic agent, a colorant, an ultraviolet absorber, a crosslinking agent, a pigment, an organic filler, and an inorganic filler may be further added to the coating liquid.

The solid content concentration of the coating liquid is usually 20% by weight or less, preferably 1 to 10% by weight. When the solid content concentration is too small, the coating property to the polyester film may be insufficient, and if the solid content concentration is too large, the stability of the coating liquid, the uniformity of the coating layer, and the appearance may be deteriorated.

The application of the aqueous coating liquid to the polyester film can be carried out at any stage. When the polyester film is an unstretched film, it can be applied at any stage after the film is formed. Further, in the case where the polyester film is a stretched film, it may be applied at any stage before, after, or during the stretching after the film formation. The application of the coating during the stretching means, for example, the case where the film is applied in the longitudinal direction and the second-axis stretching, and the film is applied after the film is longitudinally stretched and before the film is stretched in the lateral direction. In particular, when stretching is carried out using a tenter stretching machine, a zooming ceremony or a linear motor type double-axis stretching machine or the like, it is not necessary to bring the film into contact with the roller in the stretching step, so that the coating liquid is applied before being extended. The stretching and the drying of the coating liquid can be carried out in one step, so that it is a preferable structure.

When the coating liquid is applied to the polyester film, it is considered from the viewpoint of improving the coating property. The surface of the film may be subjected to corona treatment, plasma treatment, or the like in advance.

The coating amount of the coating liquid is preferably adjusted so that the thickness of the easy-adhesion layer is about 0.001 to 10 μm, more preferably about 0.001 to 5 μm, and particularly preferably about 0.001 to 1 μm. When the thickness of the coating layer is too small, the adhesion to the polarizing element may be insufficient, and if the thickness is too large, agglomeration may occur or the haze may increase.

As the coating method, any known coating method can be applied. For example, a roll coating method, a gravure printing method, a roll brushing method, a spray coating method, an air knife coating method, an impregnation method, and a curtain coating method can be provided. These may be used alone or in combination. The coating liquid applied to the polyester film is dried by heating or the like, thereby being formed on the film as an easy-adhesion layer.

[Polarizing element]

The term "polarizing element" means a film that converts natural light or polarized light into any polarized light. As the polarizing element used in the present invention, any suitable polarizing element can be employed, and it is preferred to use a person who converts natural light or polarized light into linear polarized light.

In the polarizing plate used in the present invention, as the polarizing element P, any suitable one may be employed depending on the purpose. For example, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partial saponified film is adsorbed with two colors such as iodine or a dichroic dye. A substance obtained by uniaxially extending the product, and a polyene-based alignment film such as a dehydrated material of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Further, a guest-type O-type polarizing element obtained by aligning a liquid crystal composition containing a dichroic substance and a liquid crystalline compound in a fixed direction, as disclosed in U.S. Patent No. 5,523,863, and the like, and U.S. Patent No. 6,049,428, etc. The E-type polarizing element or the like obtained by aligning the lyotropic liquid crystal in a fixed direction as disclosed therein.

Among the above polarizing elements, a polarizing element formed of a polyvinyl alcohol-based film containing iodine is preferably used from the viewpoint of having a high degree of polarization and adhesion to a polyester film having the above-mentioned easy-adhesion layer. As a material of the polyvinyl alcohol-based film applied to the polarizing element, polyvinyl alcohol or a derivative thereof is used. As a derivative of polyvinyl alcohol, a poly Examples of the vinyl aldehyde, the polyvinyl acetal, and the like include an olefin such as ethylene or propylene, an unsaturated carboxylic acid such as acrylic acid, methacrylic acid or crotonic acid or an alkyl ester thereof, and acrylamide. Modified by the winner. Usually, the polymerization degree of polyvinyl alcohol is about 1000 to 10,000, and the degree of saponification is about 80 to 100 mol%.

The polyvinyl alcohol-based film may further contain an additive such as a plasticizer. Examples of the plasticizer include a polyhydric alcohol and a condensate thereof, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of the plasticizer to be used is not particularly limited, but it is preferably 20% by weight or less in the polyvinyl alcohol-based film.

The polyvinyl alcohol-based film (unstretched film) is subjected to at least uniaxial stretching treatment or iodine dyeing treatment by a usual method. Further, boric acid treatment or iodide treatment can be carried out. Further, the polyvinyl alcohol-based film (stretched film) subjected to the above treatment is dried by a usual method to form a polarizing element.

The stretching method in the uniaxial stretching treatment is not particularly limited, and any of the wet stretching method and the dry stretching method may be employed. Examples of the stretching method of the dry stretching method include a roll stretching method, a heating roll stretching method, and a compression stretching method. Extensions can also be carried out in multiple stages. When the above extension method is employed, the unstretched film is usually in a heated state. Unstretched films are usually used in the range of 30 to 150 μm. The stretching ratio of the stretched film can be appropriately set according to the purpose, and it is desirable that the stretching ratio (total stretching ratio) is about 2 to 8 times, preferably 3 to 6.5 times, more preferably 3.5 to 6 times. The thickness of the stretched film is suitably about 5 to 40 μm.

The iodine dyeing treatment is carried out by immersing a polyvinyl alcohol-based film in an iodine solution containing iodine and potassium iodide. The iodine solution is usually an aqueous iodine solution containing iodine and potassium iodide as a dissolution aid. It is preferably used at a iodine concentration of about 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight, and a potassium iodide concentration of about 0.01 to 10% by weight, more preferably 0.02 to 8% by weight.

When performing iodine dyeing treatment, the temperature of the iodine solution is usually about 20 to 50 ° C, preferably It is 25~40 °C. The immersion time is usually about 10 to 300 seconds, preferably 20 to 240 seconds. When the iodine dyeing treatment is performed, the iodine content and the potassium content in the polyvinyl alcohol-based film can be adjusted by adjusting the concentration of the iodine solution, the immersion temperature of the polyvinyl alcohol-based film in the iodine solution, and the immersion time. The above range. The iodine dyeing treatment can be carried out before any of the uniaxial stretching treatment, the uniaxial stretching treatment, or the uniaxial stretching treatment.

The boric acid treatment can be carried out by immersing the polyvinyl alcohol-based film in an aqueous boric acid solution. The boric acid concentration in the aqueous boric acid solution is about 2 to 15% by weight, preferably 3 to 10% by weight. The boric acid solution may contain potassium ions and iodide ions by potassium iodide. The concentration of potassium iodide in the aqueous boric acid solution is preferably from about 0.5 to 10% by weight, more preferably from 1 to 8% by weight. A boric acid aqueous solution containing potassium iodide can obtain a polarizing element which is less colored, that is, a so-called neutral gray polarizing element which is substantially fixed in the entire full-wavelength range of visible light and has substantially constant absorbance.

For the iodide ion treatment, for example, an aqueous solution containing iodide ions by potassium iodide or the like is used. The concentration of potassium iodide is preferably from about 0.5 to 10% by weight, more preferably from 1 to 8% by weight. When the iodide ion is impregnated, the temperature of the aqueous solution is usually about 15 to 60 ° C, preferably 25 to 40 ° C. The immersion time is usually about 1 to 120 seconds, preferably 3 to 90 seconds. The stage of the iodide treatment is not particularly limited as long as it is before the drying step. It can also be carried out after the water washing described later.

Further, zinc may be contained in the polarizing element. When zinc is contained in the polarizing element, it is preferable to suppress the deterioration of the hue in a heating environment. The content of zinc in the polarizing element is preferably adjusted so as to contain 0.002 to 2% by weight of zinc element in the polarizing element. More preferably, it is adjusted so that the polarizing element contains 0.01 to 1% by weight of zinc element. When the zinc content in the polarizing element is in the above range, the durability improving effect is better in suppressing the deterioration of the hue.

A zinc salt solution is used in the zinc impregnation treatment. As the zinc salt, an inorganic chlorine compound such as a zinc halide such as zinc chloride or zinc iodide or an aqueous solution such as zinc sulfate or zinc acetate is suitable. Among these, zinc sulfate is preferred because it can increase the retention of zinc in the polarizing element. Also, zinc impregnation Various zinc complexes can also be used in the treatment. The concentration of zinc ions in the aqueous zinc salt solution is about 0.1 to 10% by weight, preferably 0.3 to 7% by weight. Further, when the zinc salt solution contains an aqueous solution containing potassium ions and iodide ions by potassium iodide or the like, zinc ions can be easily impregnated, which is preferable. The concentration of potassium iodide in the zinc salt solution is preferably about 0.5 to 10% by weight, more preferably 1 to 8% by weight.

When zinc is impregnated, the temperature of the zinc salt solution is usually about 15 to 85 ° C, preferably 25 to 70 ° C. The immersion time is usually about 1 to 120 seconds, preferably 3 to 90 seconds. When the zinc impregnation treatment is carried out, the zinc content in the polyvinyl alcohol-based film can be adjusted by adjusting the concentration of the zinc salt solution, the immersion temperature of the polyvinyl alcohol-based film in the zinc salt solution, and the immersion time. The stage of the zinc impregnation treatment is not particularly limited, and may be carried out before the iodine dyeing treatment, or after the boric acid aqueous solution immersion treatment after the iodine dyeing treatment, the boric acid treatment, and the boric acid treatment. Further, the zinc salt may be coexisted in the iodine dyeing solution, and subjected to zinc impregnation treatment simultaneously with the iodine dyeing treatment. The zinc impregnation treatment is preferably carried out together with the boric acid treatment. Alternatively, the uniaxial stretching treatment may be performed together with the zinc impregnation treatment. Further, the zinc impregnation treatment may be carried out plural times.

The polyvinyl alcohol-based film (stretching film) subjected to the above treatment can be supplied to the water washing step and the drying step by a usual method.

The water washing step is usually carried out by immersing the polyvinyl alcohol-based film in pure water. The water washing temperature is usually 5 to 50 ° C, preferably 10 to 45 ° C, more preferably 15 to 40 ° C. The immersion time is usually 10 to 300 seconds, preferably about 20 to 240 seconds.

The drying step may employ any appropriate drying method such as natural drying, blast drying, heat drying, and the like. For example, in the case of heat drying, the drying temperature is typically 20 to 80 ° C, preferably 25 to 70 ° C, and the drying time is typically about 1 to 10 minutes. Further, the moisture content of the polarizing element after drying is preferably from 10 to 30% by weight, more preferably from 12 to 28% by weight, still more preferably from 16 to 25% by weight. If the moisture content is too large, there is a tendency that the polarizing element and the light are passed through the bonding layer as described later. When the laminated body formed by bonding the element or the isotropic film, that is, the polarizing plate is dried, the degree of polarization decreases as the polarizing element is dried. In particular, the orthogonal transmittance in the short-wavelength region of 500 nm or less increases, that is, the light of a short wavelength leaks, so there is a tendency that the black display is colored blue. On the other hand, if the moisture content of the polarizing element is too small, there are cases where local unevenness defects (cracking defects) are likely to occur.

As the thickness of the polarizing element P used in the polarizing plate of the present invention, any appropriate thickness can be employed. The thickness of the polarizing element is typically 5 to 80 μm, preferably 10 to 50 μm, more preferably 20 to 40 μm. When the thickness of the polarizing element P is in the above range, the optical characteristics and mechanical strength are excellent.

[adhesive layer]

The polyester film E and the polarizing element P having the easy-contact layer H formed on at least one of the main surfaces are laminated so that the easy-adhesion layer forming surface of the polyester film faces the polarizing element so as to face each other via the adhesive layer G. At this time, it is desirable to laminate the two with an adhesive layer without air gap. The layer G is then formed of an adhesive. The kind of the adhesive is not particularly limited, and various adhesives can be used.

In the present invention, in the adhesive layer G in which the polarizing element P and the polyester film E are laminated, it is preferable to use a polyvinyl alcohol-based resin, a crosslinking agent, and an average particle diameter of 1 to be used as an adhesive. A resin solution of a 100 nm metal compound colloid. The polarizing element and the polarizing element protective film are usually dried after passing through the adhesive layer, but at this time, uneven defects (cracks) tend to occur. In particular, when a polyester film is used as the polarizing element protective film for the polarizing element formed of the polyvinyl alcohol film, a cellulose resin film such as cellulose triacetate which is generally used as a protective film for a polarizing element is used as In the case of the polarizing element protective film, the generation of cracks is likely to become remarkable. Therefore, in the polarizing plate of the present invention, it is preferred to use a laminate of the above composition in the lamination of the polyester film E and the polarizing element P.

The polyvinyl alcohol-based resin used as the adhesive agent may, for example, be a polyvinyl alcohol resin or a polyvinyl alcohol resin having an ethyl acetonitrile group. Polyvinyl alcohol tree with acetamidine A polyvinyl alcohol-based adhesive having a functional group having high reactivity is preferred because it can improve the durability of the polarizing plate.

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol obtained by saponifying polyvinyl acetate; a derivative thereof; and a saponified product of a copolymer of a monomer copolymerizable with vinyl acetate; A modified polyvinyl alcohol obtained by hydroformylation, urethanization, etherification, grafting, phosphation or the like. Examples of the monomer include unsaturated carboxylic acids such as maleic acid (anhydride), fumaric acid, crotonic acid, methylene succinic acid, and (meth)acrylic acid, and esters thereof; Alpha-olefin such as ethylene or propylene; (meth)allylsulfonic acid (sodium), sodium (succinic acid monoalkyl) sulfonate, sodium maleic acid disulfonate, N-methylol acrylamide, acrylamide alkyl sulfonate alkali metal salt, N-vinyl pyrrolidone, N-vinyl pyrrolidone derivative, and the like. These polyvinyl alcohol-based resins may be used alone or in combination of two or more.

The polyvinyl alcohol-based resin is not particularly limited, and the average degree of polymerization is from about 100 to 5,000, preferably from 1,000 to 4,000, and the average degree of saponification is from about 85 to 100 mol%, preferably in terms of adhesion. It is 90~100% by mole.

The polyvinyl alcohol-based resin containing an ethyl acetonitrile group can be obtained by reacting a polyvinyl alcohol-based resin with diketene by a known method. For example, a method in which a polyvinyl alcohol-based resin is dispersed in a solvent such as acetic acid, a method in which diketene is added, and a polyvinyl alcohol-based resin are previously dissolved in dimethylformamide or two A method in which a diketene is added to a solvent such as an alkane or the like. Further, a method of directly contacting the diketene gas or the liquid diketene with the polyvinyl alcohol can be mentioned.

The degree of modification of the ethyl acetyl group of the polyvinyl alcohol-based resin containing an ethyl acetonitrile group is not particularly limited as long as it is 0.1 mol% or more. If it is less than 0.1 mol%, the water resistance of the adhesive layer tends to be insufficient. The degree of modification of the acetamidine group is preferably from about 0.1 to 40 mol%, more preferably from 1 to 20 mol%, and particularly preferably from 2 to 7 mol%. When the degree of modification of the ethyl acetonitrile group exceeds 40 mol%, there is a case where a sufficient water resistance improving effect cannot be obtained. The degree of modification of the acetamidine group can be quantified by NMR (Nuclear Magnetic Resonance).

As the crosslinking agent for the adhesive, a user of the polyvinyl alcohol-based adhesive can be used without particular limitation. A compound containing at least two functional groups reactive with the above polyvinyl alcohol-based resin can be used. For example, an alkylenediamine having an alkylene group and two amine groups such as ethylenediamine, triethylenediamine or hexamethylenediamine; toluene diisocyanate, hydrogenated toluene diisocyanate, and trimethylolpropane toluene diisocyanate; An adduct, triphenylmethane triisocyanate, methylene bis(4-phenylmethane) triisocyanate, isophorone diisocyanate, and isocyanates such as ketone oxime blocks or phenol blocks; Glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, Epoxy such as diglycidyl aniline or diglycidylamine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde; glyoxal, malondialdehyde, succinaldehyde, glutaraldehyde, cis Dialdehydes such as butenaldehyde, phthalaldehyde, etc.; methylol urea, methylol melamine, alkylated methylol urea, alkylated methylolated melamine, acetamidine Benzoquinone An amine-formaldehyde resin such as a condensate with formaldehyde; furthermore, a divalent metal such as sodium, potassium, magnesium, calcium, aluminum, iron or nickel, or a salt of a trivalent metal and an oxide thereof. Among these, an amine-formaldehyde resin or a dialdehyde is preferred. As the amino-formaldehyde resin, a compound having a methylol group is preferred, and as the dialdehyde, glyoxal is preferred. Among them, particularly preferred is methylol melamine which is a compound having a methylol group.

The amount of the above-mentioned crosslinking agent can be appropriately set depending on the type of the polyvinyl alcohol-based resin in the adhesive, etc., and is usually about 10 to 60 parts by weight, preferably 20%, based on 100 parts by weight of the polyvinyl alcohol-based resin. ~50 parts by weight. Within this range, good adhesion can be obtained.

In order to improve durability, it is preferred to use a polyvinyl alcohol-based resin containing an ethyl acetonitrile group. In this case, it is also preferred that the polyvinyl alcohol-based resin 100 is in contact with the adhesive. The crosslinking agent is used in an amount of 10 to 60 parts by weight, more preferably 20 to 50 parts by weight. When the amount of the crosslinking agent is too large, the reaction of the crosslinking agent proceeds in a short time, and the adhesive tends to gel. As a result, there is a case where the service life (applicability period) as an adhesive becomes extremely short, and industrial use becomes difficult. From this point of view, the blending amount of the crosslinking agent may be the above-described blending amount, and since the resin solution of the present invention contains a colloidal metal compound, even when the amount of the crosslinking agent is large as described above, the stability can be stably maintained. Use it. The metal compound colloid used for the adhesive is a method in which fine particles are dispersed in a dispersion medium, which is electrostatically stabilized due to mutual repulsion of the same kinds of charges of the fine particles, and has permanent stability. The metal compound colloid (fine particles) has an average particle diameter of 1 to 100 nm. When the average particle diameter of the above colloid is in the above range, the metal compound can be substantially uniformly dispersed in the adhesive layer, whereby the adhesion can be ensured, and cracking can be suppressed. Since the range of the above average particle diameter is much smaller than the wavelength region of visible light, even in the formed adhesive layer, even if the transmitted light is scattered by the metal compound, the polarization characteristics are not adversely affected. The average particle diameter of the metal compound colloid is preferably from 1 to 100 nm, more preferably from 1 to 50 nm.

Various metal compound colloids can be used. For example, examples of the colloid of the metal compound include colloids of metal oxides such as alumina, ceria, zirconia, titania, aluminum silicate, calcium carbonate, and magnesium ruthenate; and metals such as zinc carbonate, cesium carbonate, and calcium phosphate. Colloid of salt; colloid of minerals such as diatomaceous earth, talc, clay, kaolin.

The metal compound gum system is dispersed in the dispersion medium to exist in the state of a colloidal solution. The dispersion medium is mainly water. In addition to water, other dispersion media such as alcohols may also be used. The solid content concentration of the colloidal metal compound in the colloidal solution is not particularly limited and is usually from about 1 to 50% by weight, more usually from 1 to 30% by weight. Further, as the metal compound colloid, an acid containing nitric acid, hydrochloric acid, acetic acid or the like can be used as a stabilizer.

The metal compound colloid is electrostatically stabilized and is classified into a material having a positive charge and a negative charge, and the metal compound colloid is a non-conductive material. The positive and negative charges are distinguished based on the state of charge of the colloidal surface charge of the solution after the preparation of the adhesive. Metallization The charge of the substance colloid can be confirmed, for example, by measuring the kinematic potential using a potentiodynamic measuring machine. The surface charge of a metal compound colloid usually varies depending on the pH. Therefore, the charge of the state of the colloidal solution of the present application is affected by the pH of the prepared adhesive solution. The pH of the subsequent solution is usually set to 2 to 6, preferably 2.5 to 5, more preferably 3 to 5, and even more preferably 3.5 to 4.5. In the present invention, the metal compound colloid having a positive charge suppresses the generation of cracks more than the metal compound colloid having a negative charge. Examples of the metal compound colloid having a positive charge include an alumina colloid, a titania colloid, and the like. Of these, particularly suitable are alumina colloids.

The metal compound colloid is preferably blended in a ratio of 200 parts by weight or less based on 100 parts by weight of the polyvinyl alcohol-based resin (converted value of the solid content). By setting the compounding ratio of the metal compound colloid to the above range, the adhesion between the polarizing element and the protective film can be ensured, and the occurrence of cracks can be suppressed. The compounding ratio of the metal compound colloid is preferably from 10 to 200 parts by weight, more preferably from 20 to 175 parts by weight, still more preferably from 30 to 150 parts by weight. When the blending ratio of the metal compound colloid to the polyvinyl alcohol-based resin is excessive, there is a case where the adhesion is poor. If the blending ratio of the colloid of the metal compound is small, the effect of suppressing the occurrence of cracks may not be obtained.

Such an adhesive is usually used as an aqueous solution. The concentration of the resin solution is not particularly limited, and the resin solution concentration is from 0.1 to 15% by weight, preferably from 0.5 to 10% by weight, in view of coatability, standing stability and the like.

The viscosity of the resin solution as an adhesive is not particularly limited, and a viscosity of 1 to 50 mPa can be suitably used. The range of s. Generally, when the polarizing element is brought into contact with the transparent protective film, as the viscosity of the adhesive decreases, the number of cracks generated increases. If the adhesive is used as described above, the viscosity of the resin solution is not affected. Limitations, even at 1~20mPa. In the low viscosity range of the range of s, the generation of cracks can also be suppressed. Compared with the conventional polyvinyl alcohol resin, the polyvinyl alcohol-based resin containing an ethyl acetate group cannot increase the degree of polymerization, and therefore, although it is used at a low viscosity as described above, since the above composition is used as the adhesive, Even when a polyvinyl alcohol-based resin containing an ethyl acetate group is used, cracking due to low viscosity of the resin solution can be suppressed.

There is no particular limitation on the preparation method of the resin solution as an adhesive. The resin solution is usually prepared by blending a metal compound colloid in a mixture in which a polyvinyl alcohol-based resin and a crosslinking agent are mixed and adjusted to an appropriate concentration. Further, when a polyvinyl alcohol-based resin containing an ethyl acetonitrile group is used as the polyvinyl alcohol-based resin, or when the amount of the crosslinking agent is large, the polyvinyl alcohol-based resin can be used in consideration of the stability of the solution. After the resin is mixed with the metal compound colloid, the crosslinking agent is mixed while considering the use period of the obtained resin solution. Further, the concentration of the resin solution as the adhesive may be appropriately adjusted after the preparation of the resin solution.

Further, a further coupling agent such as a decane coupling agent or a titanium coupling agent, various tackifiers, an ultraviolet absorber, an antioxidant, a heat stabilizer, a stabilizer such as a hydrolysis stabilizer, and the like may be further added to the adhesive. Further, the colloidal metal compound in the present application is a non-conductive material, but may also contain fine particles of a conductive material.

When the polarizing element P and the polyester film E in which the easy-contact layer H is formed are laminated by using an adhesive, the adhesive can be applied to the surface of the polyester film E which is easy to form the layer H, and the polarizing element P is used. In one case, it can also be applied to both. It is preferred to apply the adhesive so that the thickness of the adhesive layer G after drying is about 10 to 300 nm. The thickness of the adhesive layer G is more preferably from 10 to 200 nm, more preferably from 20 to 150 nm, in terms of obtaining a uniform in-plane thickness and obtaining sufficient adhesion. Further, when the above-mentioned resin solution containing a polyvinyl alcohol-based resin, a crosslinking agent, and a metal compound colloid having an average particle diameter of 1 to 100 nm is used as an adhesive, the thickness of the adhesive layer G is good. It is designed to be larger than the average particle size of the colloidal metal compound contained in the adhesive.

The method for adjusting the thickness of the adhesive layer G is not particularly limited, and examples thereof include a method of adjusting the solid content concentration of the adhesive solution or the coating device of the adhesive. The method for measuring the thickness of the adhesive layer is not particularly limited, and it is preferred to use A method of performing cross-sectional observation measurement by SEM (Scanning Electron Microscopy) or TEM (Transmission Electron Microscopy). The coating operation of the adhesive is not particularly limited, and various methods such as a roll coating method, a spray method, and a dipping method can be employed.

Further, the surface of the easy-adhesion layer H formed on the polyester film E may be further subjected to surface modification treatment before the application of the adhesive. As a specific treatment, for example, corona treatment, plasma treatment, primer treatment, saponification treatment, or the like can be performed.

After the application of the adhesive, the polarizing element P is bonded to the polyester film E by a roll laminator or the like. As described above, the moisture content of the polarizing element supplied to the bonding step is preferably from 10 to 30% by weight, more preferably from 12 to 28% by weight, still more preferably from 16 to 25% by weight. By setting the water content to the above range, the degree of polarization can be kept high, and cracking or unevenness in appearance can be prevented.

Further, from the viewpoint of stabilizing the optical properties of the polarizing degree or the color, it is preferred to apply the polyester film to both surfaces of the polarizing element and then dry at a suitable drying temperature. From the viewpoint of optical characteristics, the drying temperature is preferably 90 ° C or lower, more preferably 85 ° C or lower, and still more preferably 80 ° C or lower. Further, the drying temperature has no lower limit, but in view of the efficiency or practicability of the step, it is preferably 50 ° C or higher. Further, the drying temperature may be gradually increased in the above temperature range to be dried.

[Laminated form of polarizing plate]

In the polarizing plate of the present invention, the polyester film E on which the above-mentioned easy-adhesion layer H is formed is laminated on at least one main surface of the polarizing element P. As such an embodiment, for example, the form of Figs. 1 (a) to (c) can be mentioned. Hereinafter, the constitution of the components will be described in detail.

[Layer pattern a]

Fig. 1(a) shows a form in which a polyester film E is laminated on both main surfaces of a polarizing element P. In this form, as shown in Fig. 1(a), an easy-adhesion layer H is formed on the two polyester films E. Further, the polyester film E laminated on one main surface of the polarizing element P is laminated on the other main table The polyester film E on the surface may be the same or different.

(phase difference of polyester film)

As the polyester film E, a case where the birefringence is small, the front phase difference which does not change the polarization state is less than 40 nm, and the phase difference in the thickness direction is less than 80 nm can be used. As such a polyester film having a small birefringence, an unstretched film is suitably used.

The front phase difference Re can be expressed by Re = (nx - ny) × d. The thickness direction phase difference Rth can be expressed by Rth = (nx - nz) × d. In addition, the Nz coefficient can be expressed by Nz = (nx - nz) / (nx - ny) [wherein the refractive index of the slow axis direction, the fast axis direction, and the thickness direction of the film are nx, ny, nz, d (nm), respectively. It is the thickness of the film. In the slow axis direction, the refractive index in the plane of the film reaches the maximum direction].

On the other hand, by using a polyester film having a front phase difference of 40 nm or more and/or a thickness direction retardation of 80 nm or more, the polarizing element protective film can also function as a phase difference plate. In this case, the front phase difference or the thickness direction phase difference can be appropriately adjusted to a value necessary for optical compensation as a phase difference plate. As the retardation film, an extended polyester film can be suitably used.

Further, a polyester film E having a different phase difference value may be used on one main surface side and the other main surface side of the polarizing element P. For example, in the case of forming a liquid crystal display device, a polyester film disposed between the polarizing element and the liquid crystal cell, that is, a polyester film that is not stretched, is used, and is not disposed. The polyester film on the outer side is an extended polyester film for ensuring strength.

The phase difference plate described above may be selected and used to satisfy nx=ny>nz, nx>ny>nz, nx>ny=nz, nx>nz>ny, nz=nx>ny, nz>nx>ny, nz. >nx=ny relationship. Furthermore, ny=nz means not only the case where ny and nz are completely the same, but also the case where ny and nz are substantially the same.

For example, in a phase difference plate satisfying nx>ny>nz, it is preferable to use a front phase difference of 40 to 100 nm, a thickness direction phase difference of 100 to 320 nm, and an Nz coefficient of 1.8 to 4.5. By. For example, in a phase difference plate (positive A plate) satisfying nx>ny=nz, it is preferable to use a case where the front phase difference is 100 to 200 nm. For example, in a phase difference plate (negative A plate) satisfying nz=nx>ny, it is preferable to use a case where the front phase difference is 100 to 200 nm. For example, in a phase difference plate satisfying nx>nz>ny, it is preferable to use a case where the front phase difference is 150 to 300 nm, and the Nz coefficient exceeds 0 and is 0.7 or less. Further, as described above, for example, one satisfying nx=ny>nz, nz>nx>ny, or nz>nx=ny can be used.

(Lamination of polarizing element and polyester film)

As for the lamination of the polarizing element P and the polyester film E in which the easy-adhesion layer H is formed, it is sufficient that at least one polyester film E is laminated by the adhesive layer G, and it is preferable from the viewpoint of light use efficiency. As shown in FIG. 1(a), the two polyester films E are laminated on the polarizing element P via the adhesive layer G.

[Layered form b]

Fig. 1(b) shows a polyester film E on which one of the polarizing elements P is formed with an easy-adhesion layer H, and a transparent film T other than a polyester film laminated on the other main surface of the polarizing element P. The shape of the protective film.

(Transparent film)

The transparent film T other than the polyester is not particularly limited, and any of them can be used. As a material of such a transparent film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, and isotropic property can be used. Specific examples of the thermoplastic resin include a cellulose resin such as cellulose triacetate, a polyester resin, a polyether oxime resin, a polyfluorene resin, a polycarbonate resin, and a polyamide resin. Polyimide resin, polyolefin resin, (meth)acrylic resin, cyclic olefin resin (norbornene resin), polyarylate resin, polystyrene resin, polyvinyl alcohol Resin and mixtures of these. In addition, as the transparent film T, a thermosetting resin such as a (meth)acrylic, urethane, urethane, epoxy or an anthracene or an ultraviolet curable resin may be used. The transparent film T may contain one or more optional additives as appropriate. Examples of the additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color preventive agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The content of the above thermoplastic resin in the transparent film T is preferably from 50 to 100% by weight, more preferably from 50 to 99% by weight, still more preferably from 60 to 98% by weight, particularly preferably from 70 to 97% by weight. . When the content of the thermoplastic resin in the transparent film T is 50% by weight or less, the high transparency and the like which the thermoplastic resin originally has may not be sufficiently exhibited.

In the transparent film T, from the viewpoint of transparency or optical isotropic properties, it is preferred to use a cellulose resin, a polycarbonate resin, a cyclic olefin resin, and a (meth)acrylic acid. Any of at least one of the resins.

As the cellulose resin, a cellulose ester in which a hydroxyl group of cellulose is deuterated by a fatty acid is suitably used. Specific examples of such a cellulose ester include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Of these, particularly preferred is cellulose triacetate. Cellulose triacetate is commercially available in many products and is also advantageous in terms of ease of availability or cost. Examples of commercially available products of cellulose triacetate include "UV-50", "UV-80", "SH-80", "TD-80U", and "TD-TAC" manufactured by Fujifilm Co., Ltd. "UZ-TAC" or "KC Series" manufactured by Konica Corporation. Usually, the in-plane retardation Re of the cellulose triacetate is approximately 0, and the thickness direction retardation Rth is about 60 nm.

Further, the cellulose resin film having a small retardation in the thickness direction can be obtained, for example, by treating the above cellulose resin. For example, a base film such as polyethylene terephthalate coated with a solvent such as cyclopentanone or methyl ethyl ketone, polypropylene or stainless steel is bonded to a common cellulose resin film. After heating and drying (for example, drying at 80 to 150 ° C for 3 to 10 minutes), the substrate film is peeled off; a norbornene-based resin is dissolved in a solvent such as cyclopentanone or methyl ethyl ketone. A solution such as a (meth)acrylic resin is applied onto a common cellulose resin film and dried by heating (for example, dried at 80 to 150 ° C). After drying for about 3 to 10 minutes, the method of peeling off the coating film is used.

In addition, as the cellulose resin film having a small retardation in the thickness direction, a resin film of a cellulose ester having a controlled degree of substitution can be used. Generally, the degree of substitution of acetic acid in cellulose triacetate used is about 2.8, and it is preferred to control the degree of substitution of acetic acid to 1.8 to 2.7, whereby Rth can be reduced. Rth can be controlled to be small by adding a plasticizer such as dibutyl phthalate, p-toluenesulfonanilide or triethyl citrate to the fatty acid cellulose resin. The amount of the plasticizer added is preferably 40 parts by weight or less, more preferably 1 to 20 parts by weight, still more preferably 1 to 15 parts by weight, per 100 parts by weight of the fatty acid cellulose resin.

A specific example of the cyclic olefin resin is a norbornene-based resin. The cyclic olefin-based resin is a general term for a resin obtained by polymerizing a cyclic olefin as a polymerization unit, and examples thereof include Japanese Patent Laid-Open No. Hei No. 1-240517, Japanese Patent Laid-Open No. Hei No. 3-148882, and Japanese Patent Laid-Open No. 3- The resin described in the publication No. 122137 or the like. Specific examples thereof include a ring-opening (co)polymer of a cyclic olefin, an addition polymer of a cyclic olefin, and a copolymer of a cyclic olefin and an α-olefin such as ethylene and propylene (typically random) a copolymer), a graft polymer obtained by modifying the unsaturated carboxylic acid or a derivative thereof, a hydrogenated product thereof, and the like. Specific examples of the cyclic olefin include a norbornene-based monomer.

Cylindrical olefin resins are commercially available in various products. Specific examples include the product name "Zeonex" manufactured by Japan Zeon Co., Ltd., "Zeonor", the product name "Arton" manufactured by JSR Co., Ltd., and the trade name "Topas" manufactured by TICONA Co., Ltd., Mitsui Chemicals Co., Ltd. The company's trade name is "Apel" and so on.

The (meth)acrylic resin preferably has a Tg (glass transition temperature) of 115 ° C or more, more preferably 120 ° C or more, still more preferably 125 ° C or more, and particularly preferably 130 ° C or more. When the Tg is 115 ° C or more, the durability of the polarizing plate can be excellent. The upper limit of the Tg of the above (meth)acrylic resin is not particularly limited, and it is a viewpoint of formability and the like. In other words, it is preferably 170 ° C or less. A film having an in-plane retardation (Re) and a thickness direction retardation (Rth) of substantially 0 can be obtained from the (meth)acrylic resin.

As the (meth)acrylic resin, any suitable (meth)acrylic resin can be used without departing from the effects of the present invention. For example, poly(meth)acrylate, polymethyl methacrylate-(meth)acrylic acid copolymer, methyl methacrylate-(meth)acrylate copolymer, A Methyl acrylate-acrylate-(meth)acrylic acid copolymer, methyl (meth)acrylate-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate - a cyclohexyl methacrylate copolymer, a methyl methacrylate-(meth)acrylic acid norbornyl ester copolymer, etc.). Preferred examples thereof include poly(meth)acrylic acid C1-6 alkyl esters such as poly(methyl) acrylate. More preferably, methyl methacrylate-based resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

Specific examples of the (meth)acrylic resin include those in the molecule described in "Acrypet VH or Acrypet VRL20A, manufactured by Mitsubishi Rayon Co., Ltd., and Japanese Patent Laid-Open Publication No. 2004-70296. A (T) (meth)acrylic resin having a ring structure, a high Tg (meth)acrylic resin obtained by intramolecular crosslinking or intramolecular cyclization.

As the (meth)acrylic resin, a (meth)acrylic resin having a lactone ring structure can also be used. The reason for this is that such a (meth)acrylic resin has high heat resistance, high transparency, and high mechanical strength by biaxial stretching.

Examples of the (meth)acrylic resin having a lactone ring structure include JP-A-2000-230016, JP-A-2001-151814, JP-A-2002-120326, and JP-A. A (meth)acrylic resin having a lactone ring structure described in JP-A-2005-146084, and the like.

The (meth)acrylic resin having a lactone ring structure is preferably a compound of the following formula (1) Indicates the ring structure.

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. Further, the organic residue may also contain an oxygen atom.

The content of the lactone ring structure represented by the formula (Chemical Formula 1) in the structure of the (meth)acrylic resin having a lactone ring structure is preferably from 5 to 90% by weight, more preferably from 10 to 8% by weight. 70% by weight, further preferably 10 to 60% by weight, particularly preferably 10 to 50% by weight. When the content ratio of the lactone ring structure represented by the formula (Chemical Formula 1) in the structure of the (meth)acrylic resin having a lactone ring structure is less than 5% by weight, heat resistance, solvent resistance, and surface hardness are obtained. It may become insufficient. When the content ratio of the lactone ring structure represented by the formula (Chemical Formula 1) in the structure of the (meth)acrylic resin having a lactone ring structure is more than 90% by weight, the moldability may be insufficient.

The weight average molecular weight (sometimes referred to as a weight average molecular weight) of the (meth)acrylic resin having a lactone ring structure is preferably from 1,000 to 2,000,000, more preferably from 5,000 to 1,000,000, and even more preferably from 10,000 to 10,000. 500000, especially good is 50000~500000. When the weight average molecular weight is out of the above range, there is a case where molding processability is lacking.

The Tg of the (meth)acrylic resin having a lactone ring structure is preferably 115 ° C or more, more preferably 120 ° C or more, still more preferably 125 ° C or more, and particularly preferably 130 ° C or more. When the Tg is 115° C. or more, when the resin is formed into the transparent film T (polarizing element protective film) in the polarizing plate of the present invention and incorporated in the polarizing plate, the durability is excellent. The upper limit of the Tg of the (meth)acrylic resin having a lactone ring structure is not particularly limited, and is preferably 170 ° C or less from the viewpoint of moldability and the like.

The (meth)acrylic resin having a lactone ring structure, the higher the total light transmittance measured by the method based on ASTM-D-1003, the better the use of the molded article obtained by injection molding. It is preferably 85% or more, more preferably 88% or more, more preferably 90% or more. The total light transmittance is a standard of transparency, and if the total light transmittance is less than 85%, there is a case where the transparency is lowered.

Further, as the transparent film T, a polymer film described in JP-A-2001-343529 (WO01/37007), for example, contains (I) a substituted and/or unsubstituted fluorene on the side chain. An imine-based thermoplastic resin, and (II) a resin composition having a substituted and/or unsubstituted phenyl and nitrile-based thermoplastic resin in a side chain. Specific examples include a film containing a resin composition comprising an alternating copolymer of isobutylene and N-methylbutyleneimine and an acrylonitrile-styrene copolymer. As the film, a film containing a mixed extrusion of a resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, the unevenness caused by the strain of the polarizing plate can be eliminated, and since the moisture permeability of the films is small, the humidifying durability is excellent.

The thickness of the transparent film T can be appropriately determined, and as in the case of the above polyester film, it is preferably 5 to 500 μm, more preferably 5 to 200 μm, still more preferably 10 to 150 μm.

As the transparent film T, any one of those having a small birefringence and not exhibiting a polarization state and exhibiting a phase difference plate can be used.

In the case where the function of the retardation film is used as the transparent film T, examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, and hydroxyl group. Ethylcellulose, hydroxypropylcellulose, methylcellulose, polycarbonate, polyarylate, polyfluorene, polyethylene terephthalate, polyethylene naphthalate, polyether oxime, polyphenylene Thioether, polyphenylene ether, polyallyl hydrazine, polyamine, polyimine, polyolefin, polyvinyl chloride, cellulose resin, cyclic olefin resin (norbornene resin) or these binary Various copolymers, graft copolymers, blends, and the like of the system and the ternary system. These polymer materials form an alignment (stretching film) by stretching or the like.

Examples of the liquid crystal polymer include various liquid crystal polymers of a main chain type or a side chain type in which a linear atomic group (liquid crystal priming group) which imparts a conjugated property imparting liquid crystal alignment property is introduced into a main chain or a side chain of the polymer. . Specific examples of the main chain type liquid crystal polymer include, for example, a nematically oriented polyester-based liquid crystal polymer, a disc-shaped polymer, or a cholesterol which imparts a structure in which a liquid crystal nucleus is bonded to a spacer base. Polymers, etc. Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate or polymalonate as a main chain skeleton, and via a spacer base containing a conjugated atomic group. A liquid crystal original base having a para-substituted cyclic compound unit containing a nematic alignment imparting property is used as a side chain or the like. For the liquid crystal polymer, for example, a surface of a film of a polyimide film or a polyvinyl alcohol formed on a glass plate is subjected to a rubbing treatment, and an alignment treatment surface such as a ruthenium dioxide is obliquely vapor-deposited. On top, a solution of the liquid crystal polymer is developed and heat-treated.

The retardation plate may be, for example, a variety of wave plates or an appropriate phase difference corresponding to the purpose of use, such as compensation for coloring or viewing angle caused by birefringence of the liquid crystal layer, or two or more types may be used. The phase difference plates are stacked to control optical characteristics such as phase difference. Further, the film having the phase difference may be attached to a transparent film having no phase difference to impart the above-described function.

In addition, in terms of achieving a wide viewing angle, such as a wide viewing angle, it is also possible to use a cellulose triacetate film to support an alignment layer comprising a liquid crystal polymer, in particular, an optical anisotropy of a tilted alignment layer of a discotic liquid crystal polymer. The layer is optically compensated for the phase difference plate and the like.

The lamination of the polarizing element P and the polyester film E is performed via the adhesive layer as described above. Further, similarly to the lamination of the polarizing element P and the transparent film T, it is preferably carried out via the adhesive layer. When the polarizing element P and the transparent film T are laminated, it is preferable to use a resin solution containing a polyvinyl alcohol-based resin, a crosslinking agent, and a metal compound colloid, from the viewpoint of suppressing generation of unevenness. Further, when the polarizing element P and the transparent film T are laminated, the surface of the transparent film T may be subjected to surface modification treatment before the application of the adhesive. As For the surface modification treatment, a method of forming the above-mentioned one as an easy-contact layer of the polyester film or a corona treatment, a plasma treatment, a primer treatment, a saponification treatment or the like can be used.

[Layered form c]

Fig. 1(c) shows a state in which a polyester film E is laminated on one main surface of a polarizing element P, and a film is not laminated on the other main surface. In this embodiment, the lamination of the polarizing element P and the polyester film E is performed via the adhesive layer G as described above.

[other optical layers]

(formation of surface treatment layer)

In the polarizing plate of the present invention, if at least one polyester film E and the polarizing element P having the easy-contact layer H formed on at least one main surface are laminated, the form of the polarizing plate is not limited to the above-described laminated form (a) to (c). Any one of them can be added, and any optical layer can be added. As such an optical layer, for example, a hard coat layer or an anti-reflection treatment may be applied to the main surface of the unstacked polarizing element P of the polyester film E and/or the transparent film T, and anti-sticking, diffusion or anti-glare may be applied. For the purpose of the processor.

In the hard coat treatment, in order to prevent damage to the surface of the polarizing plate, for example, a hardened film excellent in hardness and sliding properties, which is formed of an appropriate ultraviolet curable resin such as acrylic or oxime, may be added to the above. The surface of the polyester film E and/or the transparent film T is formed, etc. The antireflection treatment is carried out in order to prevent external light reflection on the surface of the polarizing plate, and can be achieved by forming a conventional antireflection film or the like. Further, the anti-adhesive treatment is carried out in order to prevent adhesion to an adjacent layer (for example, a diffusing plate on the backlight side).

Further, the anti-glare treatment is carried out in order to prevent reflection of external light on the surface of the polarizing plate and to obstruct the transmission of light from the polarizing plate, and the like, for example, may be formed by a method of sandblasting or embossing. A fine uneven structure is applied to the surface of the polyester film E and/or the transparent film T in an appropriate manner, such as a method of blending or a method of blending transparent fine particles. As the fine particles contained in the surface fine uneven structure, for example, cerium oxide, aluminum oxide, titanium oxide, zirconium oxide, tin oxide, indium oxide, cadmium oxide, cerium oxide, or the like having an average particle diameter of 0.5 to 20 μm can be used. It also has conductive inorganic microparticles. Transparent fine particles such as organic fine particles containing a crosslinked or uncrosslinked polymer. When the surface fine uneven structure is formed, the amount of the fine particles used is usually from 2 to 70 parts by weight, preferably from 5 to 50 parts by weight, per 100 parts by weight of the transparent resin forming the surface fine uneven structure. The anti-glare layer may be a diffusion layer (viewing angle expansion function or the like) that expands the viewing angle or the like to diffuse the transmitted light from the polarizing plate.

Further, the antireflection layer, the anti-adhesion layer, the diffusion layer or the anti-glare layer may be provided separately as the optical layer in addition to the polyester film E and/or the transparent film T itself. .

In addition, examples of the optical layer which can be applied to the polarizing plate of the present invention include a brightness enhancement film, a reflection layer, a phase difference plate, and the like.

(enhanced film)

The brightness enhancement film system exhibits a characteristic that when a backlight of a liquid crystal display device or the like is incident, or natural light is incident by reflection from the back side or the like, it causes a linear polarization of a predetermined polarization axis or a circle of a predetermined direction. The polarized light is reflected, and the other light is transmitted; the light-emitting film is laminated with the polarizing plate, and the light from the light source such as the backlight is incident, and the transmitted light of a predetermined polarized state is obtained, and the light other than the predetermined polarized state is reflected and not transmitted. . The light reflected by the brightness enhancement film is further inverted by a reflection layer or the like provided on the rear side thereof, and then incident on the brightness enhancement film again, and a part or all of the incident light is transmitted as light of a predetermined polarization state. Thereby, the amount of light transmitted through the brightness enhancing film is increased, and the polarized light which is hard to be absorbed by the polarizing element is supplied, so that the amount of light available for display of an image such as a liquid crystal display is increased, whereby the brightness can be improved. A polarizing plate obtained by laminating a polarizing plate and a brightness enhancement film is provided on the backlight side of the liquid crystal cell, and may be used on the viewing side of the liquid crystal cell as disclosed in the International Publication No. WO 2006/038404. .

As the brightness enhancement film, for example, a multilayer film of a dielectric body or a multilayer laminate of films having different refractive index anisotropy can be used, and a characteristic that reflects a linear polarization of a predetermined polarization axis and reflects other light can be used. And an alignment film such as a cholesteric liquid crystal polymer or The alignment liquid crystal layer is supported by a film substrate, and any one of the left-handed or right-handed circular light is reflected and the other light is transmitted.

(reflective layer)

A reflective polarizing plate can be produced by providing a reflective layer on the polarizing plate of the present invention. The reflective polarizing plate is used to form a liquid crystal display device of a type in which incident light from a viewing side (display side) is reflected by a polarizing plate, and the light source can be omitted, and the liquid crystal display device can be omitted. It is easy to achieve the advantages of thinning. The reflective polarizing plate can be formed by a method in which a reflective layer containing a metal or the like is attached to one surface of the polarizing plate via the polyester film E or the transparent film T as needed.

Further, the semi-transmissive polarizing plate can be obtained by forming a semi-transmissive reflective layer such as a semi-mirror surface which reflects light and transmits the light in the reflective layer. The semi-transmissive polarizing plate is usually disposed on the back side (backlight side) of the liquid crystal cell, and can form a liquid crystal display device or the like of the following type: when a liquid crystal display device or the like is used in a relatively bright environment, the viewing side is made The incident light on the (display side) is reflected and displayed, and in a relatively dark environment, an image is displayed using a built-in light source such as a backlight built in the back side of the semi-transmissive polarizing plate. That is, the semi-transmissive polarizing plate can be used to form a liquid crystal display device of a type in which a light source such as a backlight can be saved in a bright environment, and a built-in light source can be used in a relatively dark environment.

[phase difference plate]

As the retardation film, a retardation film obtained by subjecting a polymer material to uniaxial or biaxial stretching treatment, an alignment film of a liquid crystal polymer, and an alignment layer supporting a liquid crystal polymer by a film may be used as described above. board.

An elliptically polarizing plate or a circularly polarizing plate will be described as an example of a laminated polarizing plate in which a phase difference plate is laminated on a polarizing plate. A phase difference plate or the like is used when converting linearly polarized light into elliptically polarized light or circularly polarized light, converting elliptically polarized light or circularly polarized light into linearly polarized light, or changing a polarization direction of linearly polarized light. Especially as converting linearly polarized light into A circularly polarized light or a phase difference plate that converts circularly polarized light into linearly polarized light can be a so-called quarter-wave plate (also referred to as a λ/4 plate). A 1/2 wave plate (also known as a λ/2 plate) is usually used when changing the direction of polarization of linear polarization.

The elliptically polarizing plate can be effectively used for compensating (preventing) the coloring (blue or yellow) generated by the birefringence of the liquid crystal layer of a super twisted nematic (STN) type liquid crystal display device, thereby performing no The case where the white and black of the above coloring is displayed. Further, it is preferable that the elliptically polarizing plate whose three-dimensional refractive index is controlled can also compensate (prevent) the coloring generated when the screen of the liquid crystal display device is viewed from the oblique direction. The circularly polarizing plate can be effectively used, for example, in the case of adjusting the image hue of a reflective liquid crystal display device in which an image is displayed in color, and the like, and also has an anti-reflection function.

Further, the elliptically polarizing plate or the reflective elliptically polarizing plate is obtained by laminating a polarizing plate or a reflective linear polarizing plate and a phase difference plate in an appropriate combination. The elliptically polarizing plate or the like may be formed by sequentially laminating the liquid crystal display device in the process of manufacturing the liquid crystal display device by forming a combination of a (reflective) polarizing plate and a phase difference plate, but as described above. When an optical compensation polarizing plate such as an elliptically polarizing plate is formed in advance, it is excellent in quality stability or lamination workability, and the manufacturing efficiency of a liquid crystal display device or the like can be improved.

The viewing angle compensation film is used to expand the film of the viewing angle so that the image can be seen relatively clearly even when the picture is viewed from a direction that is not slightly perpendicular to the screen of the liquid crystal display device. Such a viewing angle compensation phase difference plate includes, for example, an alignment film such as a retardation film or a liquid crystal polymer, or an alignment layer in which a liquid crystal polymer or the like is supported on a transparent substrate. A common phase difference plate is a polymer film having birefringence obtained by uniaxially extending in a plane direction thereof, and a phase difference plate used as a viewing angle compensation film is used for biaxial stretching in a plane direction. The obtained polymer film having birefringence; a polymer film having birefringence in which the refractive index in the thickness direction is extended in the thickness direction and which is controlled in the thickness direction, or a tilt alignment film Such as bidirectional stretching film and the like. As the oblique alignment film, for example, a heat shrinkable film is attached to the polymer film, and the film is produced by heating. Those obtained by stretching or/and shrinking the polymer film under the action of the contraction force; and those obtained by tilting the liquid crystal polymer. The material raw material polymer of the phase difference plate is the same as the polymer described in the above-mentioned phase difference plate, and can be used to prevent coloring or the like caused by a change in the viewing angle based on the phase difference of the liquid crystal cell, or to expand the visual recognition. A better perspective, etc. are suitable for the purpose.

[Lamination of optical layers]

An optical layer such as a brightness enhancement film, a reflective layer, or a retardation film can be formed by sequentially laminating in a process of manufacturing a liquid crystal display device or the like, but the laminated polarizing plate is laminated in advance to have quality stability or assembly. Excellent workability and the like, and the advantages of the manufacturing steps of the liquid crystal display device and the like can be improved. An appropriate bonding mechanism such as an adhesive layer can be used for lamination. When these layers are laminated, the optical axis of each optical layer (the slow axis of the retardation film, the absorption axis of the polarizing element, and the like) can be formed at an appropriate arrangement angle according to the target phase difference characteristics or the like.

(adhesive layer)

The optical layer of the present invention may also be laminated with an optical layer or an adhesive layer for adhering it to other members such as a liquid crystal cell. The adhesive for forming the adhesive layer is not particularly limited, and for example, an acrylic polymer, a siloxane polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine or a rubber may be appropriately selected and used. A polymer such as a base polymer. In particular, it is excellent in optical transparency such as an acrylic pressure-sensitive adhesive, and exhibits excellent wettability, cohesiveness, and adhesion properties, and is excellent in weather resistance and heat resistance.

In addition to the above, it is possible to prevent foaming or peeling due to moisture absorption, prevent deterioration of optical characteristics due to poor thermal expansion, or warp of liquid crystal cells, and further improve image quality and durability. In terms of formability of the device, etc., an adhesive layer having a low moisture absorption rate and excellent heat resistance is preferred.

The adhesive layer may also contain a resin such as a natural product or a composite, especially a tackifying resin, including a filler of glass fiber, glass beads, metal powder, other inorganic powder, and the like. Or an additive which can be added to the adhesive layer such as a pigment, a colorant, an antioxidant, or the like. Further, it may be an adhesive layer or the like which exhibits light diffusibility by containing fine particles.

The adhesive layer may be attached to one or both sides of the polarizing plate or other optical layer in an appropriate manner. As an example, for example, the base polymer or a composition thereof is dissolved or dispersed in a solvent containing a separate substance or a mixture of a suitable solvent such as toluene or ethyl acetate to prepare an adhesive of about 10 to 40% by weight. a solution solution, which is directly attached to the polarizing plate or the optical film by a suitable expansion method such as casting or coating; or an adhesive layer is formed on the separation film according to the above, and then transferred to the laminated optical film or On other optical layers.

The adhesive layer may be formed as a superposed layer of different compositions or types, and may be provided on one surface or both surfaces of the laminated optical film or other optical layer. Further, when it is provided on both surfaces, an adhesive layer having a different composition, type, or thickness may be used on the front side of the polarizing plate or the optical film. The thickness of the adhesive layer can be appropriately determined depending on the purpose of use or the adhesion, etc., and is usually 1 to 500 μm, preferably 5 to 200 μm, particularly preferably 10 to 100 μm.

(release film)

For the exposed surface of the adhesive layer, it is preferred that the release film (separation film) is temporarily attached and covered to prevent contamination or the like until the application is provided. Thereby, it is possible to prevent contact with the adhesive layer in a normal operation state. As the release film, in addition to the above thickness conditions, for example, a plastic film, a rubber sheet, a paper, a cloth, a non-woven fabric, a mesh, a foamed sheet or a metal foil, and the like, and the like can be used. The sheet is required to be coated with a suitable release agent such as a halogen-based or long-chain alkane-based, fluorine-based or molybdenum sulfide, etc., according to the prior art.

Furthermore, in the present invention, the polarizing element, the polyester film, the transparent film, or other layers of the optical layer, the adhesive, the adhesive layer, and the like which form the polarizing plate may be formed by, for example, a salicylate compound or A method of treating a UV absorber such as a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound or a nickel stear salt compound Those who have ultraviolet absorption function, etc.

[Image display device]

The polarizing plate of the present invention can be suitably used for forming an image display device such as a liquid crystal display device or an organic EL (Electro-Luminescence) display device.

(liquid crystal display device)

The liquid crystal display device is formed in accordance with the prior art. In other words, the liquid crystal display device is usually formed by laminating a liquid crystal cell and a polarizing plate, and arranging one or two or more layers such as a diffusion plate, an antiglare layer, an antireflection film, and the like at an appropriate position as needed. Suitable components such as plates, iridium arrays, lens array sheets, light diffusing plates, and backlights are incorporated into the driving circuit. In the case of forming a liquid crystal display device, there is no particular limitation other than the use of the polarizing plate of the present invention, and it can be carried out in accordance with the prior art. For the liquid crystal cell, for example, a TN (Twisted Nematic) type, an STN type, a π type, or the like can be used.

The polarizing plate of the present invention can be disposed on one side or both sides of the liquid crystal cell. When the polarizing plate is disposed on both sides, the polarizing plates may be the same or different. It is particularly preferable that the polarizing plate of the present invention is integrally bonded to the liquid crystal cell via an adhesive or the like.

(Organic EL display device)

Next, an electroluminescent device (organic EL display device) will be described. In general, an organic EL display device is formed by sequentially laminating a transparent electrode, an organic light-emitting layer, and a metal electrode on a transparent substrate to form an illuminant (organic electroluminescence illuminator). Here, the organic light-emitting layer is a laminate of various organic thin films, and for example, a composition having various combinations of a hole-laying layer containing a triphenylamine derivative or the like and a light-emitting layer containing a fluorescent organic solid such as ruthenium is known. A laminate of such a light-emitting layer and an electron implantation layer containing an anthracene derivative or the like, or a laminate of the hole implantation layer, the light-emitting layer, and the electron implantation layer.

The organic EL display device emits light by applying a voltage to the transparent electrode and the metal electrode, thereby implanting holes and electrons in the organic light-emitting layer, and recombining the holes and electrons to generate energy. Light substance, when the excited fluorescent substance is restored to the base When the state emits light. The recombination mechanism in the middle is the same as that of the ordinary diode, and it can be predicted that the current and the luminous intensity exhibit strong nonlinearity accompanying the rectification with respect to the applied voltage.

In the organic EL display device, in order to emit light from the organic light-emitting layer, at least one of the electrodes must be a transparent electrode, and a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO) is usually used as the transparent electrode. anode. On the other hand, in order to easily implant electrons and improve luminous efficiency, it is important to use a substance having a small work function at the cathode, and a metal electrode of Mg-Ag, Al-Li or the like is usually used.

In the organic EL display device having the above configuration, the organic light-emitting layer is formed of an extremely thin film having a thickness of about 10 nm. Therefore, the organic light-emitting layer can also transmit light almost completely, similarly to the transparent electrode. As a result, when the light is not emitted, the light is incident from the surface of the transparent substrate, and the light transmitted through the transparent electrode and the organic light-emitting layer and reflected by the metal electrode is again emitted to the surface side of the transparent substrate. Therefore, the organic EL display device is visually viewed from the outside. The display surface looks like a mirror.

An organic EL display device including an organic electroluminescence device having a transparent electrode on the surface side of the organic light-emitting layer that emits light by applying a voltage and having a metal electrode on the back side of the organic light-emitting layer can be used for the transparent electrode A polarizing plate is disposed on the surface side, and a phase difference plate is disposed between the transparent electrodes and the polarizing plate.

Since the phase difference plate and the polarizing plate have a function of polarizing light which is incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode cannot be visually observed from the outside by the polarizing action. In particular, when the retardation plate is formed by a quarter-wave plate and the angle formed by the polarization directions of the polarizing plate and the phase difference plate is adjusted to π/4 (90°), the mirror surface of the metal electrode can be completely shielded.

In other words, the external light incident on the organic EL display device is transmitted through only the linearly polarized light component by the polarizing plate. The linearly polarized light is usually elliptically polarized by the phase difference plate, especially when the phase difference plate is a quarter wave plate and the polarization direction of the polarizing plate and the phase difference plate is formed. When it is π/4 (90°), it will become circularly polarized.

The circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is transmitted again through the organic thin film, the transparent electrode, and the transparent substrate, and is again linearly polarized by the phase difference plate. Further, since the linearly polarized light is orthogonal to the polarization direction of the polarizing plate, it cannot be transmitted through the polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

By using the laminated optical film of the present invention in which, for example, a quarter-wave plate is obtained as an optical compensation layer in order to obtain the circularly polarized light, reflection of external light can be suppressed, and an organic EL display device having high outdoor visibility can be obtained. Moreover, similarly to the liquid crystal display device described above, the organic EL display device is also excellent in terms of excellent scratch resistance.

When the polarizing plate of the present invention is used in such an organic EL display device, a polyester film can be used as an optical compensation layer, that is, a quarter-wave plate, and a polyester film can be used only as a polarizing element. Any of the constituents of the protective film.

[Method of Forming Liquid Crystal Display Device]

[Formation Method of Liquid Crystal Display Device]

However, when forming an image display device such as a liquid crystal display device or an organic EL display device, especially when the laminated form b (Fig. 1 (b)) as described above is used, one main surface and the other main surface of the polarizing element P are used. The film laminated thereon is not the same, or as shown in the above-described laminated form c (Fig. 1 (c)), when a polarizing plate having a film laminated on only one main surface of the polarizing element P is laminated, The main surface of the side of the ester film E and the other main surface have different stresses imparted to the film interface of the polarizing element P. That is, there is a case where the external stress applied to the polarizing element is different from the front side of the film due to the difference in the layer structure of the front side of the polarizing element P. Due to the difference in external stress, the film is easily bendable. The film which is so easily bent is difficult to process into an image display device as described below in the previous manufacturing steps.

As is conceptually shown in Fig. 2, the manufacturing steps of the prior image device are roughly divided into the manufacturing steps of the optical film manufacturer and the manufacturing steps of the panel processing manufacturer. First, light The film manufacturer manufactures an optical film such as a polarizing plate as a reel material (#1) of a long strip-shaped sheet product. Then, the reel material is cut into a predetermined size (the size according to the size of the optical display unit) (#2). Then, the cut strip-shaped material is cut into a fixed size (#3) in accordance with the size of the optical display unit to be bonded, such as a liquid crystal cell or an organic EL panel. Next, the sheet product (optical film) cut into a single piece of a fixed size was subjected to visual inspection (#4). As the inspection method, for example, inspection by visual inspection and inspection using a known inspection apparatus can be cited. The term "瑕疵" refers to, for example, stains on the surface or inside, damage, impact mark defects when biting into foreign matter, uneven defects, bubbles, foreign matter, and the like. Then, the finished product inspection (#5) is performed. The finished product inspection is based on a quality product that is judged to be more stringent than the visual inspection. Next, the end faces of the squares of the one-piece sheet-like article are subjected to end surface processing (#6). The end face processing is to prevent the adhesive agent or the like from oozing out from the end face during transportation. Then, in a clean room environment, the single-piece sheet product is subjected to dust-free packaging (#7). Then, packaging (transport packaging) is carried out for transportation (#8). A single piece of sheet product is thus produced and then shipped to a panel manufacturer.

The panel processing manufacturer unpacks the single piece of the sheet product (#11). Then, a visual inspection is performed to check for damage, stains, and the like caused during transportation or unpacking (#12). The one-piece sheet product judged to be a good product in the inspection is transported to the next step. Furthermore, this visual inspection is sometimes omitted. An optical display unit (for example, a liquid crystal cell as a glass substrate unit in which a liquid crystal cell is enclosed) that is bonded to a single sheet product is preliminarily manufactured, and the optical display unit (#13) is cleaned before the bonding step.

Then, a single sheet product is attached to the optical display unit (liquid crystal cell) (#14). The release film is peeled off from the one-piece sheet product to retain the adhesive layer, and the adhesive layer is applied as a bonding surface to one side of the optical display unit. Furthermore, the other side of the optical display unit can be bonded in the same manner. In the case of bonding to both of them, the optical film of the same structure may be bonded to each surface of the optical display unit, and the optical film of a different structure may be bonded. Then, the inspection of the fit state and the inspection Check (#15). The optical display unit determined to be a good product in the inspection is transported to the mounting step, and is mounted on the image display device (#16). On the other hand, the optical display unit determined to be a defective product is subjected to rework processing (#17). In the rework process, the optical film is peeled off from the optical display unit. The optical film (#14) is reattached to the reworked optical display unit.

When the film which is easy to bend is subjected to the above-described manufacturing steps as described above, in the steps (#1) and (#2) in which the polarizing plate is present in the form of a reel, since it is erected between the conveying lines, the tension is due to the tension. And the bending behavior is suppressed. However, when it is cut into a fixed size (#3), the bending of the bending behavior of the polarizing plate is suppressed and the bending is released, and the operation of the visual inspection (#4) to the liquid crystal cell (#14) becomes difficult. Further, in the case of the previous manufacturing steps, in addition to the above-mentioned operational problems due to the bendability, there are also many problems such as inspection, packing, and the like, and there is a problem that the manufacturing cost rises.

[Manufacturing method of continuous mode]

By forming such a long reel-shaped film, the film is continuously bonded to the liquid crystal cell while being pulled down in the presence of tension, whereby the bending can be suppressed, and the above problem can be solved. In other words, the fixed size cut (#3) and the liquid crystal unit (#14) previously performed by the optical film manufacturer and the panel processing manufacturer can be continuously performed at one place, so that no visual inspection is required ( #4), finished product inspection (#5), end face processing (#6), dust-free packaging (#7), shipping package (#8), unpacking (#11), visual inspection (#12), and by bending The operational problems caused can also be solved.

When the image display device is formed by such a continuous method, the method includes: a reel material preparation step of preparing a long-length sheet of the polarizing plate of the present invention as a reel material; and a cutting step of pulling the sheet product from the reel material, The polarizing plate is cut into a predetermined size by a cutting mechanism, and a bonding step of bonding the polarizing plate to the optical display unit via the adhesive layer after the cutting step. An example of this will be described below.

[Embodiment 1 using the continuous method (normal cutting method)]

(1) First reel material preparation step (Fig. 3, S1)

The polarizing plate of the present invention formed into a long strip shape is prepared as the first reel material. The polarizing plate has a first optical film 11 in which at least one polyester film E having an easy adhesion layer H formed on at least one main surface and a polarizing element P, a first adhesive layer 14, and a first release layer The film 12 is formed. Further, the first optical film 11 may include an optical layer other than the polyester film and the polarizing element. Further, when the first optical film 11 has a configuration in which a film is laminated only on one main surface of the polarizing element P as shown in the above-described laminated form c (Fig. 1 (c)), it is preferably the first optical film. The first adhesive layer 14 and the first release film 12 are provided on the surface of the polarizing element P side of 11.

(2) First cutting step (Fig. 3, S2)

Then, the first sheet material is prepared and the first sheet material is pulled apart, and the first optical film 11 and the first adhesive layer 14 are cut into a predetermined size by a cutting mechanism, but the first sheet is not cut. 1 release film 12. Thereby, the first optical film 11 and the first adhesive layer 14 can be cut without cutting the first release film 12 . Therefore, the first optical film 11 can be formed on the first release film 12 via the first adhesive layer 14, so that the first optical film 11 does not bend. Examples of the cutting mechanism include a laser device, a cutter, and other known cutting mechanisms.

(3) First optical film bonding step (Fig. 3, S3)

Then, after the first cutting step 12, the first release film 12 is removed, and the first optical film 11 from which the first release film 12 is removed is bonded to the optical body via the first adhesive layer 14 Display on unit A. By this, even if the first release film 12 is peeled off, the first optical film 11 can be bonded to the optical display unit A while the bending of the first optical film 11 is suppressed. Examples of the optical display unit A include a glass substrate unit of a liquid crystal cell, an organic EL illuminator unit, and the like. Further, the optical display unit A is subjected to a cleaning process in advance before bonding.

The steps of the first reel material preparation step, the first cutting step, and the first optical film bonding step are performed on a continuous production line. In the series of manufacturing steps described above, The first optical film 11 is bonded to one surface of the optical display unit A. Hereinafter, a manufacturing procedure of bonding the second optical film 21 to the other surface will be described.

(4) Second reel material preparation step (Fig. 3, S4)

The strip-shaped second sheet product 2 is prepared as the second reel material. Similarly to the case of the first optical film, the laminated structure of the second sheet product 2 includes the second optical film 21, the second adhesive layer 24, and the second release film 12a. Further, as the second optical film, any optical film can be used, and a polarizing plate including a polarizing element is preferable.

(5) Second cutting step (Fig. 3, S5)

Then, the second sheet material is pulled out from the prepared second reel material, and the second optical film 21 and the second adhesive layer 24 are cut into a predetermined size as in the case of the first optical film. The second release film 12a is not cut.

(6) Second optical film bonding step (Fig. 3, S6)

Then, after the second cutting step 12a, the second release film 12a is removed, and the second optical film 21 from which the second release film 12a is removed is bonded to the second adhesive layer 24 via the second adhesive layer 24. The surface of the optical display unit A is different from the surface on which the first optical film 11 is bonded. By this means, even if the second release film 12a is peeled off, the second optical film 21 can be bonded to the optical display unit A while the bending of the second optical film 21 is suppressed. Thereby, the first optical film 11 can be bonded to one surface of the optical display unit A, and the second optical film 21 can be bonded to the other surface, and an optical display unit having optical films on both surfaces can be manufactured.

Further, each of the steps of the first reel material preparation step, the first cutting step, the first optical film bonding step, the second reel material preparation step, the second cutting step, and the second optical film bonding step is continuous Implemented on the production line.

(7) Inspection steps

It is preferred that the continuous step further has an inspection step (Fig. 3, S7). As the inspection step, an inspection step of inspecting the bonding state and an inspection step of inspecting the bonding state may be exemplified, and only one of the inspections may be performed, and it is preferable to perform inspection of both.

(8) Installation steps

The optical display unit A, which is judged to be a good product in the inspection step, is mounted in the image display device. When it is judged to be a non-conforming product, the rework process is performed, the optical film is reattached, and then the inspection is performed. If it is judged to be a good product, the process is transferred to the installation step, and if it is determined to be a non-conforming product, the process is again transferred to the rework process or Dispose of.

Further, in the embodiment described above, the polarizing plate of the present invention is used as the first optical film 11, but the polarizing plate of the present invention may be used as the second optical film 21. Further, the polarizing plate of the present invention can be used for both the first optical film 11 and the second optical film 21.

[Embodiment 2 (skip cutting method) using continuous mode]

Hereinafter, an embodiment in which the cutting is performed by the skipping cutting method will be described. This embodiment is an embodiment of the first cutting step and the second cutting step in the embodiment in which the cutting is performed in the usual manner. Deformed.

In some cases, the one end portion of the first and second reel materials in the width direction is separated by a predetermined pitch unit (for example, 1000 mm), and is encoded with a coded information (for example, a QR code (quick response code) and a bar code). Information on the first and second sheet products (瑕疵 coordinates, types and sizes of enamel, etc.). In this case, the coded information is read and analyzed at a stage before the cutting is performed, and cut into a predetermined size (sometimes called a skip) in the first and second cutting steps so as to avoid the 瑕疵 portion. Cutting). Then, the sheet containing the crucible is removed or bonded to the member of the non-optical display unit, and the sheet-like article cut into a predetermined size and judged to be a good product is attached to the optical display unit. Thereby, the yield of the optical display unit can be greatly improved, and the frequency of the rework processing (#17) can be reduced. Fig. 4 is a flow chart showing a method of manufacturing the image display device to which the cutting method (skip cutting method) is applied.

(1) First reel material preparation step (Fig. 4, S1)

In the same manner as in the case of the above-described conventional cutting method, the polarizing plate of the present invention including the first adhesive layer 14 and the first release film 12 is prepared as the first reel material.

(2) First release film removal step (Fig. 4, S61)

Then, the first sheet material is pulled out from the prepared first reel material, and the first release film 12 is removed. As a method of removing the first release film 12, for example, a method of continuously peeling the peeled film into a reel is exemplified; only the first release film is cut into a predetermined size unit and is adhered by an adhesive tape. a method of peeling off; a method of removing other steps, and the like.

(3) The first inspection step (Figure 4, S62)

Then, after the first release film removing step, a flaw inspection is performed. The first optical film 11 can be inspected without considering the phase difference between the foreign matter attached to the first release film 12 or the foreign matter or damage therein, or the phase difference in the first release film. The 瑕疵 inspection can be carried out by a known method.

(4) Second release film bonding step (Fig. 4, S63)

Then, after the first inspection step, the second release film 22 is bonded to the first optical film 11 via the first adhesive layer 14. In the case of bonding, it is preferred to carry out the lamination without generating bubbles or the like, which is preferable because the planarity can be maintained.

(5) First cutting step (Fig. 4, S64)

Then, after the second release film bonding step, the first optical film 11 and the first adhesive layer 14 are cut into a predetermined size by a cutting mechanism, but the second release film 22 is not cut. Thereby, the first optical film 11 and the first adhesive layer 14 can be cut without cutting the second release film 22 . Therefore, the first optical film 11 can be formed on the second release film 22 via the first adhesive layer 14, and therefore the first optical film 11 is not bent. Examples of the cutting mechanism include a laser device, a cutter, and other known cutting mechanisms.

(6) First optical film bonding step (Fig. 4, S65)

Then, similarly to the case of the above-described conventional cutting method, the first optical film 11 is bonded to the optical display unit A while the second release film 22 is removed.

The first reel material preparation step, the first release film removal step, and the first inspection The steps, the second release film bonding step, the first cutting step, and the first optical film bonding step are performed on a continuous production line. In the series of manufacturing steps described above, the first optical film 11 is bonded to one surface of the optical display unit A.

(7) Second reel material preparation step (Fig. 4, S4)

The strip-shaped second sheet product 2 is prepared as the second reel material. Similarly to the case of the first optical film described above, the laminated structure of the second sheet product 2 includes the second optical film 21, the third release film 12a, and the surface protective film 23.

(8) Third release film removal step (Fig. 4, S66)

Then, the second sheet material is pulled out from the prepared second reel material, and the third release film 12a is removed in the same manner as in the case of the first optical film.

(9) Step 2 inspection procedure (Fig. 4, S67)

Then, after the third release film removing step, the flaw inspection was performed in the same manner as in the case of the above first optical film.

(10) Step 4 of the release film (Fig. 4, S68)

Then, after the second inspection step, the fourth release film 22a is bonded to the second optical film 21 via the second adhesive layer 24 in the same manner as in the case of the first optical film.

(11) Second cutting step (Fig. 4, S69)

Then, after the fourth release film bonding step, the second optical film 21 and the second adhesive layer 24 are cut into a predetermined size by a cutting mechanism in the same manner as in the case of the first optical film. However, the fourth release film 22a is not cut.

(12) Second optical film bonding step (Fig. 4, S70)

Then, after the second cutting step, the second optical film after removing the fourth release film 22a while removing the fourth release film 22a is removed in the same manner as in the case of the above-described normal cutting method. 21 is bonded to the surface of the optical display unit A different from the surface on which the first optical film 11 is bonded via the second adhesive layer 24.

Further, the first reel material preparation step, the first release film removal step, the first inspection step, the second release film bonding step, the first cutting step, the first optical film bonding step, and the second reel material The steps of the preparation step, the third release film removal step, the second flaw inspection step, the fourth release film bonding step, the second cutting step, and the second optical film bonding step are carried out on a continuous production line.

(13) Inspection steps

It is preferable that the continuous step further has an inspection step as in the case of the above-described usual cutting method (Fig. 4, S7).

(14) Installation steps

The optical display unit A determined to be a good product in the inspection step is mounted in the image display device. When it is determined to be a non-conforming product, the rework process is performed, the optical film is re-attached, and then the inspection is performed. If it is judged to be a good product, the process is transferred to the installation step, and if it is determined to be a non-conforming product, the process is again transferred to the rework process or Dispose of.

[Manufacturing system suitable for manufacturing an image display device by a continuous method]

In the following, an example of an embodiment of the above-described first embodiment (a manufacturing method including a cutting step using a skip cutting method) is shown in FIGS. 5A and 5B.

As shown in FIGS. 5A and 5B, the manufacturing system includes: a first manufacturing unit that bonds the first optical film to the optical display unit; and a second manufacturing unit that bonds the second optical film to and bonded to the second optical film. 1 The optical film of the optical film has different faces on the surface of the unit.

The first manufacturing unit includes a first installation mechanism that is provided with a first reel material of the elongated first sheet product F1, and a first transport mechanism that transports the first sheet product F1 from the first reel material and transports it. a first release film removing mechanism that removes the first release film from the first sheet product that has been conveyed; and a first inspection mechanism that performs a flaw detection after removing the first release film; The film bonding mechanism is configured to bond the second release film to the first optical film via the first adhesive layer after the first inspection, and the first cutting mechanism to bond the second release After the film, the first optical film and the first adhesive layer are cut into a predetermined size, but the second release film is not cut. The first optical film bonding mechanism is after the first cutting process. After removing the second release film, the first optical film from which the second release film is removed is bonded to the optical display unit via the first adhesive; and the first control mechanism controls the respective mechanisms Gearing.

The second manufacturing unit includes a second setting mechanism that is provided with the second reel material of the long second sheet product F2, and a second conveying mechanism that pulls the second sheet product F2 from the second reel material and transports it. a third release film removing mechanism that removes the third release film from the second sheet product that has been transferred; and a second inspection mechanism that performs the flaw detection after removing the third release film; The release film bonding mechanism is characterized in that after the second inspection, the fourth release film is bonded to the second optical film via the second adhesive layer, and the second cutting mechanism is attached to the fourth release film. After the mold film, the second optical film and the second adhesive layer are cut into a predetermined size without cutting the fourth release film, and the second optical film bonding mechanism is removed after the second cutting process. In the fourth release film, the second optical film from which the fourth release film is removed is bonded to the surface of the optical display unit different from the surface on which the first optical film is bonded via the second adhesive layer. And a second control mechanism that controls to interlock the mechanisms.

The first manufacturing unit and the second manufacturing unit may be driven separately or may be driven in conjunction with each other. The first control unit and the second control unit can be configured to drive and control a series of processing steps in conjunction. Further, as shown in the first embodiment, in the manufacturing method in which the conventional method is not used for skipping cutting, the configuration in which the release film removing mechanism, the flaw detecting mechanism, and the release film bonding mechanism are omitted may be employed.

(the first manufacturing department)

The first setting mechanism 301 is provided with a first reel material of the elongated first sheet product F1, and is constituted by a roll stand device that is rotated in conjunction with a motor or the like to rotate freely or at a fixed rotational speed. The rotation speed is set by the first control unit 307, and drive control is performed.

The first conveyance mechanism 302 pulls the first sheet product F1 from the first reel material, and conveys the first sheet product F1 (or the first optical film) to each processing step. Set the tension controller at an important position in each step. The first transport mechanism 302 is controlled by the first control unit 307.

The first release film removing mechanism is configured such that the first release film is peeled off from the conveyed first sheet product F1 and wound up in a roll shape. The winding speed of the rolls is controlled by the first control unit 307. The peeling mechanism (see FIG. 5A) has a blade having a sharp tip end, and the first release film is wound around the blade and then reversely transferred, whereby the first release film is peeled off and the first release film is peeled off. The first sheet product F1 after the mold film is conveyed in the conveyance direction.

The first inspection mechanism 303 performs a flaw inspection after removing the first release film. The first inspection mechanism 303 is a CCD (Charge-Coupled Device) camera or a CMOS (Complementary Metal-Oxide-Semiconductor) camera, and transmits the acquired image data to the first control unit 307. . The first control unit 307 analyzes the image data, detects the flaw, and calculates the position coordinates. The position coordinates of the crucible are supplied to the skip cutting of the first cutting mechanism described later.

After the first release film bonding mechanism, the second release film is bonded to the first optical film via the first adhesive layer after the first inspection. As shown in FIG. 5A, the second release film is pulled from the reel material of the second release film, and the second release film and the first optical film are sandwiched by one pair or a plurality of pairs of rollers, and the roller pair is used. The established pressure works and fits it. The rotation speed, pressure control, and conveyance control of the roller pair are controlled by the first control unit 307.

After the first release film 304 is bonded to the second release film, the first optical film and the first adhesive layer are cut into a predetermined size, but the second release film is not cut. The first cutting mechanism 304 is a laser device. The first cutting mechanism 304 is cut into a predetermined size so as to avoid the dam portion according to the position coordinates of the cymbal detected in the first 瑕疵 inspection process. That is, the cut product including the enamel portion is excluded as a defective product in the subsequent step. Alternatively, the first cutting mechanism 304 may be continuously cut into a predetermined size, regardless of the presence of the crucible. In this case, in the bonding process described later, it may be configured to remove or paste the portion without bonding the portion. Combined with the temporary board unit. Control at this time is also performed by the first control unit 307.

Further, in the first cutting mechanism 304, a holding table that sucks and holds the first sheet product F1 from the back surface is disposed, and a laser device is provided above the first sheet product F1. The laser beam is horizontally moved in the width direction of the first sheet product F1 to be scanned, and the first optical film, the first adhesive layer, and the protective film are cut at a predetermined pitch in the transport direction (hereinafter, appropriately referred to as "Half cut") while retaining the second lower release film. Further, the laser device preferably has an air nozzle that blows warm air toward the cutting portion and is self-cut by the warm air conveyance so as to be sandwiched in the width direction of the first sheet product F1. The collecting pipe of the gas (smoke) generated at the part is integrally formed in a state of being opposed to each other. When the first sheet product F1 is adsorbed by the holding stage, the step rollers 302a and 302b configured as the conveying means are moved in the vertical direction so that the first sheet product F1 on the downstream side and the upstream side of the holding table Continuous transfer does not stop. This operation is also performed by the control of the first control unit 307.

After the first cutting process, the first optical film bonding mechanism removes the second release film, and the first optical film from which the second release film is removed is bonded to the optical via the first adhesive layer. Display unit W. As shown in FIG. 5B, at the time of bonding, the first optical film 1 is pressed against the surface of the optical display unit W by the pressing roller 305, and the bonding is performed. The pressing pressure and operation of the roller 305 are controlled by the first control unit 307. The peeling mechanism is configured to have a sharp-edged cutting edge N1, and the second release film 22 is wound around the blade and then conveyed in the reverse direction (reverse transfer), thereby being transported together with the second release film 22 The second release film is peeled off and removed from the optical film 1, and the first optical film 1 from which the second release film is peeled off is conveyed to the lower portion of the center of the pressing roller 305 by the tip end thereof, and is sent to the optical display unit W surface. on. In this case, peeling is performed in a state where a tension of 150 N/m or more and 1000 N/m or less is applied to the second release film, and/or the second release film is removed from the first optical film until the pressing roller is pressed. When the optical film is moved vertically downward and the optical film is pressed against the surface of the optical display unit W and pressed at a predetermined pressure within 3 seconds, the bonding precision between the first optical film and the optical display unit can be improved. If the tension is less than 150 N/m, the sending position of the first optical film is unstable, and if it is larger than At 1000 N/m, the second release film may be stretched and broken, or the optical characteristics may vary. Further, when the time until the pressure is applied is longer than 3 seconds, the end portion of the first optical film peeled off from the second release film may be bent and broken or may be generated. The bonding mechanism is composed of a pressing roller 305 and a guide roller 3051 disposed opposite thereto. The guide roller is constituted by a rubber roller driven by a motor, and is vertically provided with a pressing roller 305 formed of a metal roller driven by a motor so as to be lifted and lowered, when the optical display unit W is fed to the bonding position The pressing roller 305 is raised to a position higher than its upper surface to open the roller interval. Furthermore, the guide roller 3051 and the pressing roller 305 may both be rubber rollers or may be metal rollers. The optical display unit W is stored in advance after being washed. The optical display unit W is disposed in the transport mechanism by the adsorption transport mechanism 306. This control is also performed by the control of the first control unit 307.

(the second manufacturing department)

In each step of the second manufacturing unit, the second installation mechanism 401, the second conveyance mechanism 402, the third release film removal mechanism, the second inspection mechanism 403, the fourth release film bonding mechanism, and the second cutting mechanism The configuration of 404 is the same as the mechanism corresponding to the first manufacturing unit, and thus the description thereof is omitted.

The optical display unit W1 manufactured by the first manufacturing unit is transported to the second manufacturing unit. The optical display unit W1 is vertically inverted during the transfer or in the second manufacturing unit. The up-and-down reversing mechanism (not shown) is configured such that the optical display unit W1 is sucked from the upper surface by the suction mechanism, and the optical display unit W1 is lifted up, reversed upside down, and placed on the transport mechanism again. This control utilizes the function of the second control unit 407. Further, as another embodiment, a configuration in which the up-and-down inversion processing is not performed may be employed. In this case, in the second manufacturing unit, the second sheet product F2 is processed in the reversed state (the release film is the upper surface), and the lower side of the optical display unit is different from the normal one. The second optical film is bonded. When the second optical film is to be bonded to the first optical film at 90° (orthogonal polarization), the optical display unit W1 is rotated by 90°, and the second optical film is bonded.

The first control unit 307 and the second control unit 407 perform control so that the above-described mechanisms in the respective steps are linked. Each action sequence is configured by a sensor located at a given position, or by using a rotation The encoder or the like detects the rotating member of the conveying mechanism and calculates it. The first and second control units 307 and 407 can be realized by a synergistic action between a software program and a hardware resource such as a CPU (Central Processing Unit) and a memory. In this case, the program software and processing are performed. The order and various settings are stored in advance in the memory. Further, the first and second control mechanisms 307 and 407 may be configured by a dedicated circuit or a firmware.

In the above embodiment, the sheet product including the enamel portion is bonded to the temporary plate unit and recovered, but it may be attached to a belt-shaped separation film for winding and recovery.

The 瑕疵 inspection can be performed by a known inspection method. Examples of the flaw detection method include an automatic inspection device and a visual inspection by an examiner. The automatic inspection device is a device for automatically inspecting a flaw (also referred to as a defect) of a sheet product, which irradiates light and acquires a reflected light image of the irradiated light via an imaging unit such as a line sensor or a two-dimensional TV camera or The transmitted light image is detected based on the acquired image data. Further, image data is acquired in a state in which the inspection polarizing film is inserted in the optical path between the light source and the imaging unit. Usually, the polarization axis (for example, the polarization absorption axis) of the polarizing film for inspection is arranged in a state orthogonal to the polarization axis (for example, the polarization absorption axis) of the polarizing plate to be inspected (orthogonal polarization). By arranging the orthogonal polarization, if there is no flaw, the image of the all black is input from the imaging unit, and if there is 瑕疵, the 瑕疵 portion is not black (identified as a bright spot). Therefore, 瑕疵 can be detected by setting an appropriate threshold. In the above-described bright spot detection, flaws such as surface adhering substances and internal foreign matter are detected as bright spots. Further, in addition to the bright spot detection, there is a method of detecting a foreign matter by capturing a transmitted light image of an object by a CCD camera and performing image analysis. Further, there is a method of detecting a foreign matter adhering to a surface by capturing a reflected light image of an object by a CCD camera and performing image analysis.

[Examples]

Hereinafter, the present invention will be described by way of examples, but the present invention is not limited by the examples shown below. In addition, the evaluation of the following examples, reference examples, and comparative examples was carried out by the following method.

[test methods]

(peel strength)

A strip-shaped sample cut into a width (TD) direction of 15 mm × length (MD) direction of 150 mm was used. The "starting" portion of the state in which the polyester film and the polarizing element were peeled off was set on the sample. The sample was attached to a glass plate with a double-sided tape (manufactured by Nitto Denko Corporation, No. 500), and the first portion was sandwiched on a variable angle peeling tester (manufactured by Asahi Seiko Co., Ltd.) at a peeling angle of 90° and a peeling speed. The peel strength (N/15 mm) between the polarizing element and the polyester film was measured under the conditions of 3000 mm/min. Further, the measurement was carried out in an environment at a temperature of 23 °C.

(Appearance check: crack defect)

The polarizing plate was cut into a rectangle of 500 mm in the TD direction and 2000 mm in the MD direction, and two polarizing plates were laminated on the brightness by a commercially available iodine-based polarizing plate (manufactured by Nitto Denko, trade name "SED1423DU") orthogonal to the transmission axis. On the 8000 candela/m ² fluorescent lamp, visually count the number of leaks (cracking defects).

(the amount of curling of the polarizing plate)

A sample cut into an A4 size (270 mm in the TD direction × 297 mm in the MD direction) was used. As the measurement environment, the temperature was 23 ° C and the humidity was 55% RH.

First, the sample was allowed to stand on a water platform for about 10 seconds to confirm the bending direction. After confirming the bending direction, it was allowed to stand for 10 minutes to make the sample concave (bent into a cup shape from the side). Then, using a stainless steel ruler (JIS class 1), the height from the surface of the stage on which the film was placed to the upper end of the curved sample was visually measured.

(Tensile elastic modulus of film)

A strip-shaped sample piece having a width of 10 mm in the measurement direction (TD or MD) and having a sufficient length was cut. In other words, when measuring the elastic modulus in the MD direction, a sample piece having a width of 10 mm in the TD direction and a length of 100 mm in the MD direction is cut, and when the elastic modulus in the TD direction is measured, the MD direction is cut. A sample piece having a width of 10 mm and a length in the TD direction of, for example, 100 mm. Use at 25 ° C temperature environment Tensile tester (Tensilon) was subjected to a tensile test under the conditions of a tensile speed of 50 mm/min and a distance between the chucks of 10 mm.

The initial rise of the SS (Strain-Strength) curve obtained by the tensile test is tangent, and the intensity (tensile strength) at which the extension line of the tangent reaches 100% elongation is used, and the strength is used. The value is divided by the measured cross-sectional area (thickness × sample width (10 mm)) of the sample piece, and the obtained value is taken as a tensile elastic modulus (generally, sometimes referred to as Young's modulus).

[Formation of Easy Adhesive Layer on Polyester Film]

(Manufacturing Example 1)

After corona treatment of a biaxially stretched polyethylene terephthalate film (T-100 manufactured by Mitsubishi Chemical Polyester Film) having a thickness of 38 μm, a coating tester equipped with a gravure roll of mesh #200 was used. A polyester-based water-dispersed urethane adhesive (manufactured by Daiichi Kogyo Co., Ltd., trade name "Superflex SF210") was applied and dried at 150 ° C for 1 minute to form a polyethylene terephthalate film. An easy-to-layer layer having a thickness of 0.3 μm.

(Manufacturing Example 2)

30 parts by weight with respect to 100 parts by weight of a polyvinyl alcohol-based resin having an ethyl acetonitrile group (average degree of polymerization: 1200, degree of saponification of 98.5 mol%, degree of modification of acetamidine group of 5 mol%) Share The oxazoline-based crosslinking agent (manufactured by Nippon Shokubai Co., Ltd., trade name "WS-700") was dissolved in pure water at a temperature of 30 ° C to prepare an aqueous solution having a solid concentration of 3.7% by weight. This aqueous solution was applied onto a biaxially stretched polyethylene terephthalate film which was subjected to corona treatment in the same manner as in the above Production Example 1 using a wire bar (#20), and dried at 130 ° C for 5 minutes to form an aqueous solution. An easy-to-layer layer having a thickness of 0.3 μm.

[Manufacture of polarizing element]

(Manufacturing Example 3)

A polyvinyl alcohol film having an average degree of polymerization of 2,700 and a thickness of 75 μm was stretched and conveyed while being dyed between rolls having different circumferential speeds. First, the polyvinyl alcohol film is applied at 30 ° C on one side. The mixture was immersed in a water bath for 1 minute to swell, and was extended to 1.2 times in the transport direction, and then dyed by immersing in an aqueous solution having a potassium iodide concentration of 30 ° C and a iodine concentration of 0.3% by weight for 1 minute. One side is extended to three times in the direction of conveyance with a film that is not extended (the original length) as a reference. Then, it was immersed in an aqueous solution having a boric acid concentration of 4% by weight and a potassium iodide concentration of 5% by weight at 60 ° C for 30 seconds, and was extended to 6 times in the transport direction with respect to the original length. Then, the obtained stretched film was dried at 70 ° C for 2 minutes, whereby a polarizing element was obtained. Further, the polarizing element had a thickness of 30 μm and a water content of 14.3% by weight.

[Preparation of adhesive]

(Manufacturing Example 4)

50 parts by weight with respect to 100 parts by weight of a polyvinyl alcohol-based resin having an ethyl acetonitrile group (average degree of polymerization: 1200, degree of saponification of 98.5 mol%, degree of modification of acetamidine group of 5 mol%) The methylol melamine was dissolved in pure water at a temperature of 30 ° C to prepare an aqueous solution having a solid concentration of 3.7% by weight. To 100 parts by weight of the aqueous solution, 18 parts by weight of an aqueous solution containing a positively charged alumina colloid (having an average particle diameter of 15 nm) at a solid concentration of 10% by weight was added to prepare an aqueous solution of a metal colloid-containing adhesive. The viscosity of the subsequent solution is 9.6 mPa. s, the pH is in the range of 4 to 4.5, and the amount of the alumina colloid is 74 parts by weight based on 100 parts by weight of the polyvinyl alcohol-based resin.

Further, the average particle diameter of the alumina colloid was measured by a dynamic light scattering method (optical correlation method) using a particle size distribution meter (manufactured by Nikkiso Co., Ltd., product name "Nanotrac UAP150").

(Manufacturing Example 5)

An aqueous solution of a metal colloid-free adhesive was prepared in the same manner as in the above Production Example 4 except that 18 parts by weight of pure water was added instead of 18 parts by weight of the aqueous alumina colloid solution.

[Manufacture of transparent protective film]

(Manufacturing Example 6)

A copolymer having a copolymer of methyl methacrylate (MMA) and methyl 2-(hydroxymethyl)acrylate (MHMA) was obtained in the same manner as in Example 1 in the specification of JP-A-2000-23016. A (meth)acrylic resin particle having a lactone ring structure obtained by condensation. The pellet was dissolved in methyl ethyl ketone, and a film was formed by a solution casting method. The film was uniaxially stretched 1.5 times at a rate of 0.1 m/min at 100 ° C to obtain a lactone ring-containing acrylic resin film having a thickness of 30 μm.

[Manufacture of polarizing plate]

(Example 1)

The adhesive of the production example 4 was applied to the easy-adhesion layer forming surface of the polyester film having an easy-to-attach layer obtained in Production Example 1 so that the thickness of the adhesive layer after drying became 80 nm. The two main surfaces of the polarizing element obtained in Production Example 3 were bonded to each other using a roller press, and dried at 70 ° C for 6 minutes to prepare a polarizing plate.

(Example 2)

In the above-mentioned Example 1, a polarizing plate was produced in the same manner as in Example 1 except that the polyester film obtained in Production Example 2 was used instead of the polyester film obtained in Production Example 1.

(Reference example 1)

In the above-mentioned Example 1, a polarizing plate was produced in the same manner as in Example 1 except that the adhesive of Production Example 5 was used instead of the adhesive of Production Example 4.

(Reference example 2)

In the above-mentioned Example 2, a polarizing plate was produced in the same manner as in Example 2 except that the adhesive of Production Example 5 was used instead of the adhesive of Production Example 4.

(Comparative Example 1)

In the above-mentioned Example 1, a polarizing plate was produced in the same manner as in Example 1 except that the polyester film which did not form an easy-adhesion layer was used instead of the polyester film obtained in Production Example 1.

(Comparative Example 2)

In the above Comparative Example 1, the use of the adhesive of Production Example 5 was used instead of the production example 4. A polarizing plate was produced in the same manner as in Comparative Example 1, except for the primer.

The composition of the polarizing plate obtained in the above examples, the reference examples, and the comparative examples, the peel strength of the polyester film and the polarizing element, and the results of inspection of the appearance (crack) are shown in Table 1.

In the examples 1 and 2 and the reference examples 1 and 2 in which the polyester film had an easy-adhesion layer, the force was large, and the limit (upper limit) of the peel strength was exceeded, and the film was broken.

From the above results, it is clear that the polarizing plates of Examples 1 and 2 are excellent in adhesion between the polarizing element and the protective film, so that the protective film is less likely to be convex or peeled off. Further, since the adhesive containing the metal colloid was used for laminating the polarizing element and the polyester film, the cracks were less generated and the appearance was better than those of Reference Examples 1 and 2 using the adhesive containing no metal colloid.

(Example 3)

On both main surfaces of the polarizing element obtained in Production Example 3, the adhesive of Production Example 4 was applied so that the thickness of the adhesive layer after drying became 80 nm, and a roller press was used for one of the polarizing elements. A biaxially stretched polyester film having an easy-to-attach layer obtained in Production Example 1 was attached to the main surface, and a cellulose triacetate film was attached to the other main surface of the polarizing element (Konica Minolta) The company's KC4UY) was dried at 70 ° C for 6 minutes to prepare a polarizing plate. Further, in the same manner as in the first embodiment, the biaxially stretched polyester film having an easy-adhesion layer was laminated so that the easy-adhesion layer forming surface of the polyester film faced the polarizing element.

(Examples 4 to 10)

A polarizing plate was produced in the same manner as in Example 3 except that the film shown in Table 2 was used instead of the cellulose triacetate film of Example 3 (KC4UY manufactured by Konica Minolta Co., Ltd.).

(Example 11)

The adhesive of the production example 4 was applied to the easy-adhesion layer forming surface of the polyester film having an easy-to-attach layer obtained in Production Example 1 so that the thickness of the adhesive layer after drying became 80 nm. The main surface of one of the polarizing elements obtained in Production Example 3 was bonded to the main surface of the polarizing element obtained in Production Example 3, and dried at 70 ° C for 6 minutes to prepare a polarized light in a state in which the transparent film was not laminated on the other main surface of the polarizing element. board.

The transparent film used in the polarizing plates of Examples 1 and 3 to 11 and the elastic modulus of each transparent film and the measurement result of the crimp of the polarizing plate are shown in Table 2.

In Table 2, the symbol "+" of the amount of crimping indicates that the film is curled so that the surface on which the biaxially stretched polyester film is laminated is inside, and the symbol "-" indicates that the film is laminated on the side on which the biaxially stretched polyester film is laminated. Curl in the way. Further, MD and TD indicate curling in the MD direction and the TD direction, respectively.

In the polarizing plate of the third embodiment, since the film is formed inside the surface on which the biaxially stretched polyester film is laminated, the film is curled into a cylindrical shape in the MD direction, so that the amount of curl cannot be measured. Further, the diameter of the cylinder was visually measured using a stainless steel ruler (JIS class 1), and as a result, it was 60 mm. Further, the polarizing plate of Example 9 was similarly crimped into a cylindrical shape having a diameter of 40 mm. In the polarizing plate of the eleventh embodiment in which the transparent film is not laminated on the main surface of one of the polarizing plates, the film is rolled into a tubular shape in the TD direction so that the surface on which the biaxially stretched polyester film is laminated is outside. The diameter of the cylinder was measured in the same manner as in the polarizing plate of Example 3, and as a result, it was 38 mm.

As is clear from Table 2, the polarizing plate of Example 1 which used the same polyester film on both sides in accordance with the constitution of Fig. 1(a) of the present application did not cause curling, whereas, with respect to Fig. 1(b) The polarizing plates of Examples 3 to 11 which conformed to the constitution of (c) produced curl. The larger the difference between the elastic modulus of the polyester film laminated on one main surface of the polarizing element and the transparent film laminated on the other main surface, the larger the amount of curling, the inferring of the curl of the polarizing plate It is caused by the difference in the modulus of elasticity of the film laminated on the polarizing plate.

As described above, in the state in which the curl is generated, it is difficult to perform the single-plate operation on the polarizing plate. However, by applying the manufacturing method using the continuous method of the present invention, the image display device can be manufactured regardless of whether or not the curl is generated.

E‧‧‧ polyester film

G‧‧‧ adhesive layer

H‧‧‧Easy layer

P‧‧‧ Polarized components

T‧‧‧Transparent film

Claims (3)

A method of manufacturing an image display device which is carried out in a continuous manner, wherein the image display device bonds a polarizing plate to an optical display element via an adhesive layer; the manufacturing method includes: a reel material preparation step, preparing the above a long strip of polarizing plate as a reel material; a cutting step of pulling a sheet product from the reel material, cutting the polarizing plate into a predetermined size using a cutting mechanism; and a bonding step in the cutting step Thereafter, the polarizing plate is bonded to the optical display unit via an adhesive layer; the polarizing plate is formed with a polyester film (E) having an easy-adhesion layer (H) on at least one main surface, via an adhesive layer (G) a layer laminated on one main surface of the polarizing element (P), which is laminated with the easy-to-layer formation surface of the polyester film opposite to the polarizing element; the other main surface of the polarizing element (P) is not laminated Film; the polyester film (E) is an unstretched polyester film. The method of producing an image display device according to claim 1, wherein the adhesive layer (G) is formed of an adhesive containing a polyvinyl alcohol resin, a crosslinking agent, and an average particle diameter of 1 to 100 nm. The metal compound colloidal resin solution is prepared, and the metal compound gum system is formulated in a ratio of 200 parts by weight or less based on 100 parts by weight of the polyvinyl alcohol-based resin. The method of producing an image display device according to claim 1, wherein the easy-adhesion layer (H) contains a polyvinyl alcohol-based derivative or a polyurethane compound.