KR20070030823A - Phase difference plate with protective film, method for manufacture thereof, pressure-sensitive adhesion type phase difference plate with protective film and pressure-sensitive adhesion type optical material with protective film - Google Patents

Abstract

In the retardation plate with a protective film of the present invention, at least two protective films having an adhesive layer on one side of the base film are sequentially bonded to the retardation plate, and the first protective film and the first protective film are bonded to the retardation plate. The other protective films have different adhesive strengths to the adherends, and the first protective films have the smallest adhesive strengths. Such a retardation plate with a protective film can suppress the generation of curl even in the case of a thin retardation plate, and also has good workability and good peelability.

Protective film, retardation plate, adhesive layer

Description

PHASE DIFFERENCE PLATE WITH PROTECTIVE FILM, METHOD FOR MANUFACTURE THEREOF, PRESSURE-SENSITIVE ADHESION TYPE PHASE DIFFERENCE PLATE WITH PROTECTIVE FILM AND PRESSURE-SENSITIVE ADHESION TYPE OPTICAL MATERIAL WITH PROTECTIVE FILM}

Field of technology

The present invention relates to a retardation plate with a protective film and a method of manufacturing the same. Retardation plates are used in various image display devices such as liquid crystal display devices, organic EL display devices, and PDPs. The retardation plate with a protective film can provide a bonded or bonded product of the retardation plate without impairing workability and appearance in the production process.

In addition, the present invention relates to a pressure-sensitive adhesive retardation plate with a protective film in which an adhesive layer is formed on the retardation plate with a protective film. The pressure-sensitive adhesive retardation plate with a protective film can be used as a pressure-sensitive adhesive optical material with a protective film bonded to an optical film such as a polarizing plate used in the various image display devices, and an optical material including glass or plastic film.

Background

Retardation plates are used in liquid crystal displays and other various displays. As a retardation plate, the stretched film obtained by uniaxial stretching or biaxial stretching of polymer films, such as a polycarbonate, cyclic polyolefin, polyester, cellulose, polyimide, or these modified substances, is known. Moreover, the liquid crystal aligning film obtained by coating and aligning liquid crystal materials, such as a liquid crystal monomer and a liquid crystal polymer, on an orientation base material and fixing by hardening etc. is known. Moreover, these laminated bodies are used as retardation plate. Although the thickness of the retardation plate was 60 micrometers or more conventionally, thickness reduction is progressing year by year. Recently, the thickness of the retardation plate is about 1 to 60 µm.

The retardation plate is usually cut into an arbitrary shape, and the retardation plates are laminated in various sheets or with other optical materials in various image display apparatuses. In addition, a protective film is usually bonded to the retardation plate for the purpose of preventing breakage and the like. However, due to the thinning of the retardation plate and a slight tension difference when bonding the protective film to the retardation plate, large curls are generated in the cut product (retardation plate), which makes it difficult to bond with other optical materials. There is. In addition, when handling the cut products, there is a problem that folds are generated and local stresses are applied, resulting in partial retardation change, breakage or breakage in the retardation plate.

As a protective film for retardation plates, the adhesive film which has a base film and an adhesive layer using polyolefin resin, such as polyethylene, a polypropylene, and a polyethylene- polypropylene mixture, is used, for example (refer patent document 1). However, since curling increases with thinning of the retardation plate, even when such a protective film is used, folds are likely to occur and are easily damaged, and the protective film is insufficient in the protective film. For these problems, there is a method of increasing the thickness of the base film used for the protective film. In this method, however, the adhesion to the thin retardation plate is usually worsened, and the protective film is lifted or peeled off. In order to improve the problem, it is conceivable to increase the adhesive force of the protective film, but when the adhesive force is increased, the peelability required for the protective film cannot be satisfied.

As the material of the base film of the protective film, a polyester resin such as polyethylene terephthalate having a high protective function is used in addition to the polyolefin resin. However, since the polyethylene terephthalate film and the thin retardation plate have a large elastic modulus difference, it is not possible to solve the problem of easy curling. In addition, in general, since the protective film is often too high adhesion to the thin retardation plate, it is difficult to peel off the protective film. When the protective film with low adhesive force is used in order to improve the said problem, it may lift or peel off by the adhesiveness with a thin retardation plate.

Patent Document 1: Japanese Unexamined Patent Publication No. 2002-363510

Disclosure of the Invention

Problems to be Solved by the Invention

An object of this invention is to provide the retardation plate with a protective film which can suppress generation | occurrence | production of a curl, also has good workability, and is excellent in peelability, even when used for a thin retardation plate, and its manufacturing method.

In addition, an object of the present invention is to provide a pressure-sensitive adhesive retardation plate with a protective film obtained from the retardation plate with a protective film, and to provide an adhesive optical material with a protective film.

Means to solve the problem

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the present inventors discovered that the said objective can be achieved by the following protective film for retardation plates, and came to complete this invention.

That is, in the present invention, at least two protective films having an adhesive layer on one side of the base film are sequentially bonded to the retardation plate, and the protective films other than the first protective film and the first protective film bonded to the retardation plate are The adhesive force with respect to each to-be-adhered body differs, and it is related with the retardation plate with a protective film characterized by the smallest adhesive force of a 1st protective film.

In the retardation plate with a protective film of the present invention, a plurality of protective films are laminated on the retardation plate. Therefore, even when the retardation plate is thin, it is possible to secure a thickness enough to suppress the generation of curl as the entire protective film. Moreover, since a some protective film is laminated | stacked on the retardation plate in order, adhesiveness is also favorable. Moreover, since the one with the smallest adhesive force among the protective films is bonded to the retardation plate as the first protective film, it can be suppressed to be lifted or peeled off between the protective films to be laminated.

In addition, since the retardation plate with a protective film of the present invention is protected by a plurality of protective films, it is possible to suppress the occurrence of problems such as local breakdown during handling during processing, and to form a product with good workability. can do. Moreover, generation | occurrence | production of a curl can also be reduced also about the cut phase plate.

Moreover, since the retardation plate with a protective film of this invention has the smallest adhesive force of the 1st protective film directly bonded to a retardation plate, the laminated multilayer protective film can be peeled at once from a retardation plate, and peelability is also favorable. .

In the retardation plate with a protective film, it is preferable that the difference between the adhesive force between the first protective film bonded to the retardation plate and the second protective film adjacent thereto is 0.05 N / 50 mm or more.

In order to ensure the favorable peelability of the said protective film, it is necessary to prevent peeling at the interface of protective films. From the viewpoint of such peelability, it is preferable that the adhesive force at the interface between the protective films be 0.05 N / 50 mm or more than the adhesive force at the interface between the retardation plate and the first protective film. As for the difference of the said adhesive force, 0.07 N / 50 mm or more and 0.09 N / 50 mm or more are preferable. It is preferable that it is 2 N / 50 mm or less and 1.5 N / 50 mm or less from a viewpoint of the bonding property of a 2nd protective film.

When laminating | stacking 3 or more layers of protective films, it is preferable to make it the adhesive force of the 3rd or more 3rd protective film also be 0.05 N / 50 mm or more than the adhesive force of the interface of a retardation plate and a 1st protective film. In the case where three or more layers of protective films are laminated, the difference in their adhesive strengths is within the range of ± 0.5 N / 50 mm so that the adhesive strength of the second or more protective films is about the same, so that peeling at the interface between the protective films does not occur. It is preferable to adjust so that.

In the retardation plate with a protective film, it is preferable that the adhesive force of the first protective film bonded to the retardation plate is 0.01 to 0.3 N / 50 mm.

It is preferable to set the adhesive force of the protective film bonded to the retardation plate to the said range from a peelable property and the protective function of a protective film. More preferably, the adhesive force of the 1st protective film joined to the retardation plate is 0.02-0.2N / 50mm. If the adhesive force is higher than 0.3 N / 50 mm, problems such as deformation of the retardation plate tends to occur when the first protective film is peeled from the retardation plate, and the working speed may be slowed down. Moreover, when adhesive force is lower than 0.01 N / 50 mm, problems, such as peeling from a retardation plate in various processes, may arise.

In the retardation plate with a protective film, a polyolefin-based film is preferable as the base film of the first protective film bonded to the retardation plate, and a polyester-based film is preferable as the base film of the other protective film.

Since a polyolefin film has a low elastic modulus compared with a polyester film, the 1st protective film which uses a polyolefin film as a base film can perform favorable bonding to a retardation plate. And by bonding the 2nd protective film which uses a polyester film with a high elasticity modulus as a base film here, the curl which arose by the 1st protective sheet which uses a polyolefin type film as a base film can be reduced. In the case where the protective sheets are bonded to and laminated on the retardation plates in this order, the handling properties when the cut products of the retardation plates are bonded to other optical materials in a single sheet can be improved, and the occurrence of problems such as destruction can be suppressed.

In the said retardation plate with a protective film, even when the thickness of a retardation plate is 1-60 micrometers thin, it can use preferably.

In addition, the thickness of the retardation plate to which the retardation plate with a protective film of the present invention is applied is not particularly limited, and may be applied even when the thickness is out of the above thickness. In particular, it is preferable to adapt to a retardation plate using a material which is prone to retardation change, folding, cracking and breaking depending on handling.

In addition, the present invention is a method for manufacturing the retardation plate with a protective film, a protective film having an adhesive layer on one side of the base film, by preparing at least two protective films different in adhesion to each adherend to the smallest adhesive force After bonding a 1st protective film to a retardation plate, It is related with the manufacturing method of the retardation plate with a protective film characterized by bonding another protective film in order.

The present invention also relates to a pressure-sensitive adhesive retardation plate with a protective film, characterized in that the pressure-sensitive adhesive layer on the side of the protective film with the protective film is not bonded.

The present invention also relates to a pressure-sensitive adhesive optical material with a protective film, wherein the pressure-sensitive adhesive retardation plate with a protective film is laminated with other optical materials with the pressure-sensitive adhesive layer interposed therebetween.

A pressure-sensitive adhesive layer may be formed on the retardation plate with a protective film of the present invention to form an adhesive retardation plate with a protective film, and the protective film-type adhesive retardation plate may have good handling properties without causing problems such as destruction to other optical materials. Since it can be laminated | stacked and a multilayer protective film can be peeled easily, it can manufacture the product form of the optical material containing retardation plate with a good yield.

Brief description of the drawings

1 is an example of sectional drawing of the retardation plate with a protective film of this invention.

2 is an example of sectional drawing of the adhesive retardation plate with a protective film of this invention.

3 is an example of sectional drawing of the adhesive optical material with a protective film of this invention.

* Description of the sign *

11: first protective film 12: second protective film

2: retardation plate 3: adhesive layer

4 separator 5 optical material

To practice the invention  Best form for

Hereinafter, the retardation plate with a protective film, the pressure-sensitive adhesive retardation plate with a protective film, and the pressure-sensitive adhesive optical material with a protective film of the present invention will be described with reference to the drawings.

FIG. 1: is sectional drawing which shows the retardation plate with a protective film, The 1st protective film 11 and the 2nd protective film 12 are bonded in this order to one side of the retardation plate 2. As shown in FIG. The first protective film 11 has an adhesive layer 11b on one side of the base film 11a. The second protective film 12 has an adhesive layer 12b on one side of the base film 12a. In FIG. 1, although the case where two protective films are laminated | stacked is shown, if the number of lamination | stacking of a protective film is two or more, there is no restriction | limiting in particular. However, since the increase in the number of laminated protective films leads to an increase in cost, the number of laminated protective films is preferably about two or three layers.

In addition, the 1st protective film 11 bonded by the retardation plate 2 uses the thing with the smallest adhesive force among the protective films laminated | stacked. In FIG. 1, the 1st protective film 11 uses what is smaller in adhesive force than the 2nd protective film 12. As shown in FIG. Even when laminating | stacking three or more layers of protective films, the 1st protective film 11 uses the thing with the smallest adhesive force.

FIG. 2 shows the pressure-sensitive adhesive layer 3 formed on the side where the first protective film 11 and the second protective film 12 of the retardation plate 2 are not bonded in the retardation plate with the protective film of FIG. 1. It is sectional drawing of the adhesion type retardation plate with a protective film. As shown in FIG. 2, you may form the separator 4 in the adhesive layer 3.

3 is a cross-sectional view of an optical material with a protective film in which another optical material 5 is laminated with the pressure-sensitive adhesive layer 3 of the pressure-sensitive adhesive retardation plate with a protective film of FIG. 2 interposed therebetween. The optical material 5 can use what laminated | stacked several optical materials.

As a retardation plate, the birefringent film formed by carrying out uniaxial or biaxial stretching process of a polymeric material, for example is mentioned. These high molecular materials become alignment materials (stretched films) by stretching or the like. As a polymer material, for example, polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyallylate, poly Polyolefins such as sulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyphenylene sulfide, polyphenylene oxide, polyallyl sulfone, polyvinyl alcohol, polyamide, polyimide, cyclic polyolefin, polyvinyl chloride, cellulose type Polymers or their binary, ternary, various copolymers, graft copolymers, modified substances, blends and the like.

Moreover, as a retardation plate, the liquid crystal aligning film obtained by apply | coating and orienting liquid crystal materials, such as a liquid crystal monomer and a liquid crystal polymer, and fixing by hardening etc. is mentioned. Examples of the liquid crystal polymer include various main chain and side chain types in which the conjugated linear atomic group (mesogen) for imparting liquid crystal orientation is introduced into the main chain or side chain of the polymer. As a specific example of a main chain | strand-type liquid crystalline polymer, the nematic oriented polyester liquid crystalline polymer, the discotic polymer, the cholesteric polymer, etc. of the structure which couple | bonded the mesogenic group in the spacer part which gives flexibility is mentioned, for example. Can be. Specific examples of the side chain type liquid crystalline polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as main chain skeletons, and are arranged in a side chain with a spacer portion composed of a conjugated atomic group as a side chain. The thing which has the mesogenic part which consists of substituted cyclic compound units, etc. are mentioned. These liquid crystalline polymers are, for example, a solution of a liquid crystalline polymer on an alignment treatment surface such as rubbing a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate or depositing silicon oxide on all sides. It is prepared by developing, heat-treating, orientating, and then cooling and fixing. Furthermore, the liquid crystal monomer which can form the said liquid crystal polymer is unfolded on an orientation treatment surface, heat-processed, orientated, and what was hardened | cured by the ultraviolet-ray etc. is mentioned.

The retardation plate may have a suitable retardation according to the purpose of use, for example, for the purpose of compensating coloring or vision due to birefringence of various wavelength plates and the liquid crystal layer, or by laminating two or more kinds of retardation plates to form a phase difference. The optical characteristic of this may be controlled.

The protective film has an adhesive layer on one side of the base film. In general, the base film and the pressure-sensitive adhesive layer can be used without any particular limitation on the protective film, and the first protective film, the second protective film, or the like is selected and used.

As a base film used for a protective film, the film material which has isotropy or approximate isotropy is generally chosen from a viewpoint of the inspection property, manageability, etc. of the optical film by clairvoyance. Examples of the film material include polyester resins such as polyethylene terephthalate, cellulose resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, and polyolefin resins. Transparent polymers, such as resin and acrylic resin, are mentioned. The base film may be comprised by two or more layers.

You may add light stabilizers, such as antioxidant, a ultraviolet absorber, a hindered amine light stabilizer, for example, to the base film, for the purpose of prevention of deterioration. In addition, antistatic agents, and other additives such as fillers such as calcium oxide, magnesium oxide, silica, zinc oxide, titanium oxide, pigments, antifog agents, lubricants, antiblocking agents, crosslinking agents, and the like can also be blended.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer of the protective film is an acrylic pressure-sensitive adhesive, ethylene-vinyl acetate copolymer, natural rubber pressure-sensitive adhesive, polyisobutylene, butyl rubber, styrene-butylene-styrene (SBS), styrene-isoprene-styrene block air Synthetic rubber adhesives, such as coalescence, are mentioned. These can be used as a mixture.

If necessary, adhesives such as rosin-based resins, terpene-based resins, aromatic petroleum resins, polybutenes, polyisobutenes, coumarone-indene resins, phenol resins, and xylene resins may be applied to the pressure-sensitive adhesives for the purpose of controlling such properties and adhesive strength. The adhesive composition to which resin and the softening agent were added can be used. The pressure-sensitive adhesive may also contain fillers, anti-aging agents, crosslinking agents, pigments and the like. Moreover, an adhesive layer can also be formed in a protective base as an overlapping layer of a thing with a different composition, a kind, etc.

As a manufacturing method of a protective film, the multilayer coextrusion method which extrudes the material of a base film and an adhesive simultaneously by inflation or a T die can be employ | adopted, for example. Moreover, you may employ | adopt the method of extruding a base film and an adhesive separately separately, and laminating after that. Moreover, a protective film can be manufactured by laying an adhesive layer in a suitable method to a base film. For example, a base polymer or the like is dissolved or dispersed in a solvent composed of a single substance or a mixture of a suitable solvent such as toluene or ethyl acetate to prepare a pressure-sensitive adhesive liquid of about 10 to 40% by weight, and suitable development such as a casting method or a coating method. The method of directly laying on a protective base material by the method, or the method of forming an adhesive layer on a separator according to the above, and sticking it to a base film are mentioned. On the surface of the base film which forms an adhesive layer, suitable surface treatment, such as a corona treatment, can be performed for the purpose of improving adhesive force with an adhesive layer, etc.

In the protective film, an antistatic layer may be formed on one side or both sides of the base film for the purpose of antistatic at the time of peeling.

As a 1st protective film, what used polyolefin resin among the base film materials illustrated above is preferable. As polyolefin resin, olefin resin includes copolymer resins, such as an olefin homopolymer type, some olefins, and a block polymer using a different monomer, a random polymer, etc., Specifically, a propylene polymer, low density polyethylene, high density polyethylene Olefins such as ethylene polymers such as medium density polyethylene, linear low density, ethylene / propylene copolymers, ethylene-α-olefin copolymers, olefin polymers such as reactor TPO, ethylene / methyl methacrylate copolymers, and other monomers. The olefin copolymer of is illustrated. Among these, polyethylene, polypropylene, a mixture of polyethylene and polypropylene, and a polyethylene propylene copolymer are preferable.

Moreover, as an adhesive layer of a 1st protective film, an acrylic adhesive and an ethylene-vinyl acetate copolymer are preferable.

The thickness of the base film and the adhesive layer of a 1st protective film is suitably determined. The thickness of a base film is generally about 10-200 micrometers, Preferably it is 20-100 micrometers. The thickness of an adhesive layer is 1-200 micrometers generally, Preferably it is 5-100 micrometers.

On the other hand, as a material of the base film used for protective films other than a 1st protective film, polyester-type resin is preferable. In particular, polyethylene terephthalate is preferable. As an adhesive used for such a protective film, an acrylic adhesive is preferable. Although an acrylic adhesive is demonstrated below, this is applicable not only to the protective film other than a 1st protective film but also to a 1st protective film.

An acrylic adhesive is obtained by crosslinking the acrylic polymer obtained by copolymerizing various acryl monomers. Examples of the acrylic monomer include linear or branched chains such as methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, nonyl and decyl groups. And esters of acrylic acid and methacrylic acid having an alkyl group. In addition, for the purpose of improving the adhesive properties by introducing functional groups and polar groups, improving cohesive force and heat resistance by controlling the glass transition temperature of the resultant copolymer, and modifying the adhesive properties such as increasing molecular weight by providing crosslinking reactivity, etc. Carboxyl group-containing monomers such as acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; Acid anhydride monomers such as maleic anhydride or itaconic anhydride; And hydroxyl group-containing monomers such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and hydroxyhexyl (meth) acrylate. And (N-substituted) amide monomers such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, and N-methylol (meth) acrylamide; Alkyl (meth) acrylate alkylaminoalkyl monomers such as aminoethyl (meth) acrylate and N, N-dimethylaminoethyl (meth) acrylate; Alkoxy (meth) acrylate alkyl monomers, such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; Maleimide monomers, such as N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, and N-phenyl maleimide, etc. can also be used. And itaconic imide monomers such as N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaciconimide and N-octyl itaciconimide; Succinimide monomers such as N- (meth) acryloyloxymethylene succinimide and N- (meth) acryloyl-6-oxyhexamethylene succinimide; Vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinyl Vinyl monomers, such as morpholine, N-vinylcarboxylic acid amides, styrene, (alpha) -methylstyrene, and N-vinyl caprolactam, etc. can also be used. Further cyanoacrylate monomers such as acrylonitrile, methacrylocotryl; Epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; Glycol-based acrylic ester monomers such as polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, and methoxypolypropylene glycol (meth) acrylate; Acrylic acid ester system monomers, such as (meth) acrylic acid tetrahydrofurfuryl, a fluorine (meth) acrylate, a silicone (meth) acrylate, and 2-methoxyethyl acrylate, can also be used. In addition, divinylbenzene, butyl diacrylate, hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di ( Meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, Polyfunctional monomers, such as polyester acrylate and urethane acrylate, etc. can also be used.

The preparation of the acrylic polymer can be performed by, for example, applying a suitable method such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method or the like to a mixture of component monomers. The acrylic polymer preferably has a weight average molecular weight of 100,000 or more, more than 200,000, particularly 300,000 to 2 million, from the viewpoint of heat resistance and adhesive properties.

An acrylic adhesive layer can also be crosslinked by suitable methods, such as an internal crosslinking system and an external crosslinking system. Generally, the external crosslinking method which mix | blends a crosslinking agent with an intermolecular crosslinking agent to an adhesive is employ | adopted. As an intermolecular crosslinking agent, a polyfunctional isocyanate crosslinking agent, an epoxy crosslinking agent, a melamine resin crosslinking agent, a metal salt crosslinking agent, a metal chelate crosslinking agent, an amino resin crosslinking agent, a peroxide type crosslinking agent, etc. are mentioned, for example.

In addition, the thickness of the base film and the adhesive layer of protective films other than a 1st protective film is suitably determined. The thickness of a base film is generally about 10-200 micrometers, Preferably it is 20-100 micrometers. The thickness of an adhesive layer is 1-200 micrometers generally, Preferably it is 5-100 micrometers.

In the retardation plate with a protective film of the present invention, at least two protective films having different adhesion to each adherend are prepared, and after bonding the first protective film to the retardation plate so that each adhesive force becomes a relationship as shown above, It is obtained by bonding other protective films in order.

The retardation plate may be an adhesive retardation plate having an adhesive layer on a side where the protective film is not bonded. In this case, an adhesive retardation plate with a protective film is obtained.

The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, but for example, an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine-based rubber or a polymer such as fluorine-based polymer may be appropriately selected and used. Can be. In particular, an acrylic adhesive has excellent optical transparency, exhibits proper wettability, cohesiveness, and adhesive adhesion characteristics, and has excellent weather resistance, heat resistance, and the like, and can be preferably used.

In addition to the above, in view of prevention of foaming or peeling phenomenon due to moisture absorption, reduction of optical characteristics due to thermal expansion difference, prevention of warpage of liquid crystal cells, and further, formation of a high quality and durable liquid crystal display device, The adhesive layer which is low in rate and excellent in heat resistance is preferable.

An adhesive layer is added to adhesive layers, such as fillers, pigments, coloring agents, antioxidants which consist of resins of a natural substance or a compound, especially tackifying resin, glass fiber, glass beads, metal powder, and other inorganic powders, etc., for example. You may contain the additive of what becomes. Moreover, the adhesive layer etc. which contain microparticles | fine-particles and show light diffusivity may be sufficient.

Laying an adhesive layer with respect to retardation plate can be performed in a suitable manner. Examples thereof include a 10-40 wt% pressure-sensitive adhesive solution prepared by dissolving or dispersing a base polymer or a composition thereof in a solvent composed of a single substance or a mixture of a suitable solvent such as toluene or ethyl acetate, and casting it in a flexible manner. The method of directly attaching to a retardation plate by a suitable development method, such as a coating method, or the method of forming an adhesive layer on a separator according to the above, and sticking it on a retardation plate, etc. are mentioned.

The pressure-sensitive adhesive layer may be formed on the retardation plate as an overlapping layer of one having a different composition or kind. The thickness of an adhesive layer can be suitably determined according to a purpose of use, adhesive force, etc., Generally, 1-500 micrometers and 5-200 micrometers are preferable, and 10-100 micrometers is especially preferable.

The exposed surface of the pressure-sensitive adhesive layer is temporarily bonded and covered with a separator for the purpose of preventing contamination thereof until it is provided for practical use. For this reason, contact with an adhesive layer can be prevented in a usual handling state. As the separator, except for the above thickness conditions, for example, a plastic film, a rubber sheet, a paper, a cloth, a nonwoven fabric, a net, a foam sheet or a metal foil, and a laminate of a suitable type such as a laminate thereof may be silicone-based or long-chain alkyl-based, Conventional suitable ones, such as those coated with a suitable release agent such as fluorine or molybdenum sulfide, can be used.

Each layer such as the retardation plate and the pressure-sensitive adhesive layer is treated with an ultraviolet absorber such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound or a nickel complex salt compound. The thing which gave ultraviolet absorption ability by the system etc. may be sufficient.

Moreover, the adhesive type retardation plate with a protective film can be made into the optical material with a protective film laminated | stacked with the other optical material through the said adhesive layer.

Examples of the optical material include various optical films, glass or plastic films. As the surface of the optical material, a material having a suitable surface treatment such as saponification treatment, corona treatment or anchor coat treatment can be used. Such surface treatment can improve the adhesion between the retardation plate and the optical material.

A polarizing plate is mentioned as an optical film. The polarizing plate is generally used to have a transparent protective film on one side or both sides of the polarizer. In such a polarizing plate, the activation treatment is performed on the surface of the protective film.

A polarizer is not specifically limited, Various things can be used. As a polarizer, the dichroic substance of an iodine or a dichroic dye is made to adsorb | suck to hydrophilic polymer films, such as a polyvinyl alcohol-type film, a partially formalized polyvinyl alcohol-type film, and an ethylene-vinyl acetate copolymerization partial soapy film, for example. And polyene-based alignment films such as uniaxially stretched, dehydrated polyvinyl alcohol and dehydrochloric acid polyvinyl chloride. Among these, the polarizer which consists of dichroic substances, such as a polyvinyl alcohol-type film and iodine, is preferable. Although the thickness in particular of these polarizers is not restrict | limited, Usually, it is about 5-80 micrometers.

The polarizer which uniaxially stretched the polyvinyl alcohol-type film by iodine, for example, can be prepared by dyeing polyvinyl alcohol by dipping in an aqueous solution of iodine and stretching it 3 to 7 times its original length. It can also be immersed in aqueous solution, such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride, etc. as needed. If necessary, the polyvinyl alcohol-based film may be immersed in water and washed before dyeing. By washing the polyvinyl alcohol-based film with water, the dirt or the blocking agent on the surface of the polyvinyl alcohol-based film can be washed, and the polyvinyl alcohol-based film is swelled to prevent irregularities such as staining. Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be dyed with iodine after stretching. It can extend | stretch also in aqueous solution, such as boric acid and potassium iodide, or a water bath.

As a material for forming the transparent protective film formed on one side or both sides of the polarizer, one having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polystyrene and acrylonitrile styrene copolymer ( Styrene-based polymers such as AS resin), polycarbonate-based polymers, and the like. Polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene-propylene copolymers, amide polymers such as vinyl chloride polymers, nylon and aromatic polyamides, imide polymers, sulfones Polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer, epoxy Examples of the polymer forming the transparent protective film may also be cited as the system polymer or the blend of the polymer. The transparent protective film may be formed as a cured layer of thermosetting or ultraviolet curable resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone.

Furthermore, the polymer film described in JP 2001-343529 A (WO01 / 37007), for example, a thermoplastic resin having a substituted and / or unsubstituted imide group in (A) side chain, and (B) a substituted and / or unsubstituted side chain The resin composition containing the thermoplastic resin which has cyclic phenyl and a nitrile group is mentioned. As a specific example, the film of the resin composition containing the alternating copolymer which consists of isobutylene and N-methyl maleimide, and an acrylonitrile styrene copolymer is mentioned. As a film, the film which consists of a mixed extrusion product of a resin composition, etc. can be used.

Although the thickness of a transparent protective film can be suitably determined, it is generally about 1-500 micrometers from a viewpoint of workability, thin-film property, etc., such as strength and handleability. 5-200 micrometers is especially preferable.

Moreover, it is preferable that a transparent protective film does not have a color as much as possible. Therefore, in the film thickness direction represented by Rth = [(nx + ny) / 2-nz] · d (where nx and ny are the main refractive indices in the film plane, nz is the refractive index in the film thickness direction and d is the film thickness). The transparent protective film whose phase difference is -90 nm-+75 nm is used preferably. By using the thing whose phase difference value Rth of such a thickness direction is -90 nm-+75 nm, coloring (optical coloring) of the polarizing plate resulting from a transparent protective film can be almost eliminated. The thickness direction retardation Rth is more preferably -80 nm to +60 nm, particularly -70 nm to +45 nm.

As a transparent protective film, cellulose polymers, such as a triacetyl cellulose, are preferable from a viewpoint of polarization characteristic, durability, etc. In particular, a triacetyl cellulose film is preferable. In addition, when forming a transparent protective film on both sides of a polarizer, the transparent protective film which consists of the same polymer material may be used in the front and back, and the transparent protective film which consists of different polymer materials etc. may be used. The polarizer and the transparent protective film are usually in close contact with each other through an aqueous adhesive. As an aqueous adhesive agent, an isocyanate adhesive, a polyvinyl alcohol adhesive, a gelatin adhesive, a vinyl latex type, an aqueous polyurethane, an aqueous polyester, etc. can be illustrated.

The surface which does not adhere the polarizer of the said transparent protective film may be the thing which carried out the process for the purpose of a hard-coat layer, an anti-reflective process, sticking prevention, and diffused or anti-glare.

Hard coat treatment is carried out for the purpose of preventing damage to the surface of the polarizing plate, for example, a method of adding a cured coating having excellent hardness and sliding characteristics, such as acrylic or silicone type, to the surface of the transparent protective film. Or the like. The antireflection treatment is performed for the purpose of antireflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the prior art. In addition, the sticking prevention treatment is performed for the purpose of preventing the adhesion with the adjacent layer of the other member.

In addition, antiglare treatment is carried out for the purpose of preventing external light from reflecting off the surface of the polarizing plate and impairing the visibility of the transmitted light of the polarizing plate, for example, a roughening method or a transparent fine particle by sandblasting or embossing. It can be formed by imparting a fine concavo-convex structure on the surface of the transparent protective film in a suitable manner, such as the mixing method. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include a conductive material composed of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, or the like having an average particle diameter of 0.5 to 50 µm. Transparent fine particles such as organic fine particles (including beads) made of inorganic fine particles, crosslinked or uncrosslinked polymers, and the like are used. When forming a surface fine uneven structure, the use amount of microparticles | fine-particles is about 2-50 weight part generally with respect to 100 weight part of transparent resin which forms a surface fine uneven structure, and 5-25 weight part is preferable. The antiglare layer may also serve as a diffusion layer (visual magnification function or the like) for diffusing the polarized plate transmitted light to enlarge the time and the like.

The anti-reflection layer, the anti-sticking layer, the diffusion layer or the antiglare layer may be formed on the transparent protective film itself, or may be formed as a separate optical layer from the transparent protective film.

Moreover, as an optical film, it is used for formation of a liquid crystal display device, such as a reflecting plate, a semi-transmissive plate, a retardation plate (including wavelength plates, such as 1/2 or a quarter), a visual compensation film, a brightness enhancement film, etc. The thing which becomes the optical layer which may become is mentioned. These can be used independently as an optical film, and can be laminated | stacked on the said polarizing plate practically, and can use 1 layer or 2 or more layers. As a retardation plate, the above things can be illustrated.

In particular, a reflective polarizer or transflective polarizer in which a reflection plate or a semi-transmissive reflector is laminated in addition to the polarizer, an elliptical polarizer or circular polarizer in which a retardation plate is laminated on the polarizer again, a wide viewing angle polarizer in which a visual compensation film is laminated on the polarizer again, Or the polarizing plate in which a brightness improving film is laminated | stacked again on a polarizing plate is preferable.

The reflective polarizer is formed by forming a reflective layer on the polarizer, and is used to form a liquid crystal display device of a type that reflects and displays incident light from the viewer side (display side), and can incorporate a light source such as a backlight. It is advantageous in that the liquid crystal display device can be made thinner. Formation of a reflective polarizing plate can be performed by a suitable method, such as a method of laying a reflective layer made of metal or the like on one surface of the polarizing plate with a transparent protective layer interposed therebetween as necessary.

As a specific example of a reflection type polarizing plate, the thing which formed the reflection layer by laying the foil and vapor deposition film which consist of reflective metals, such as aluminum, on one surface of the transparent protective film which carried out the mat process as needed. In addition, the fine particles are contained in the transparent protective film so as to have a surface fine concavo-convex structure, and the like having a reflective layer having a fine concavo-convex structure thereon. The reflective layer of the fine uneven structure has the advantage that the incident light can be diffused by diffuse reflection to prevent directivity and glare, thereby suppressing unevenness in contrast. In addition, the fine particle-containing protective film also has an advantage that the incident light and the reflected light is diffused when passing through it to further suppress the light and shade unevenness. Formation of a reflective layer having a fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film, for example, may form a metal on the surface of the transparent protective layer by a suitable method such as vacuum deposition, ion plating, sputtering or plating. It can carry out by the method of laying directly.

The reflecting plate can also be used as a reflecting sheet or the like formed by forming a reflecting layer on a suitable film based on the transparent film instead of the method directly applied to the transparent protective film of the polarizing plate. Since the reflective layer is usually made of metal, the use of the reflective surface coated with a transparent protective film, a polarizing plate or the like prevents the reduction of the reflectance due to oxidation, and furthermore, the long-term persistence of the initial reflectance and the laying of a protective layer separately. It is preferable from the viewpoint of avoiding the above.

The semi-transmissive polarizing plate can be obtained by forming a semi-transmissive reflecting layer such as a half mirror that reflects and transmits light through the reflecting layer. The semi-transmissive polarizing plate is usually formed on the rear side of the liquid crystal cell. When using a liquid crystal display or the like in a relatively bright atmosphere, the semi-transmissive polarizing plate reflects the incident light from the viewer side (display side) to display an image. The liquid crystal display device of the type which displays an image etc. can be formed using the built-in power supply, such as a backlight built in the backside of this. That is, the semi-transmissive polarizing plate can save energy of using a light source such as a backlight in a bright atmosphere, and is useful for forming a liquid crystal display device of the type that can be used using a built-in power supply even in a relatively dark atmosphere.

An elliptical polarizing plate or circular polarizing plate in which a retardation plate is further laminated on the polarizing plate will be described. A retardation plate or the like is used to change linearly polarized light into elliptical polarization or circularly polarized light, to change elliptical polarization or circularly polarized light into linearly polarized light, or to change the polarization direction of linearly polarized light. In particular, a so-called quarter wave plate (also referred to as λ / 4 plate) is used as a phase difference plate for converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light. A half wave plate (also called a λ / 2 plate) is usually used to change the polarization direction of linearly polarized light.

The elliptical polarizing plate is effectively used for compensating (preventing) the coloration (blue or yellow) caused by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device to perform monochrome display without the coloration. The control of the three-dimensional refractive index is preferable because it can compensate (prevent) the coloration generated when the screen of the liquid crystal display device is viewed in the oblique direction. The circular polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflection type liquid crystal display device in which an image becomes color display, and also has an antireflection function.

The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a phase difference plate in a suitable combination. Such elliptical polarizing plates and the like can be formed by separately stacking them in order in the manufacturing process of the liquid crystal display device so as to be a combination of the (reflective) polarizing plate and the retardation plate. There is an advantage that the manufacturing efficiency of the liquid crystal display device and the like can be improved due to the excellent quality stability and lamination workability.

The visual compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly inclined direction rather than perpendicular to the screen. Such a visually compensated retardation plate consists of, for example, supporting an alignment layer such as a liquid crystal polymer on an alignment film such as a retardation plate or a liquid crystal polymer or a transparent substrate. A conventional retardation plate is a polymer film having birefringence stretched uniaxially in its plane direction, whereas a retardation plate used as a visual compensation film is a polymer film having birefringence stretched biaxially in the plane direction, A bidirectional stretched film, such as a birefringent polymer or a diagonally oriented film, which has a refractive index in the thickness direction that is stretched in one plane in the plane direction and also in the thickness direction, is used. Examples of the inclined alignment film include those in which the polymer film is stretched and / or shrunk under the action of the shrinkage force by heating and the slant-oriented liquid crystal polymer is adhered to the polymer film. . The raw material polymer of the retardation plate is the same as the polymer described in the above retardation plate, and is suitable for the purpose of preventing the coloring due to the change of the viewing angle based on the phase difference by the liquid crystal cell, and expanding the viewing angle with good visibility. Can be used.

In addition, in order to achieve a wide viewing angle with good visibility, an optical compensation retardation plate which supports an optically anisotropic layer composed of an alignment layer of a liquid crystal polymer, in particular an inclined alignment layer of a discotic liquid crystal polymer, can be preferably used. .

The polarizing plate which bonded the polarizing plate and the brightness enhancement film is usually formed on the back side of the liquid crystal cell and used. The luminance enhancing film is characterized by reflecting linearly polarized light on a predetermined polarization axis or circularly polarized light in a predetermined direction and transmitting other light when natural light is incident due to reflection from a backlight or a backside of a liquid crystal display device or the like. The polarizing plate laminated | stacked with the polarizing plate injects light from a light source, such as a backlight, and acquires the transmitted light of a predetermined polarization state, and reflects the light other than the said predetermined polarization state without transmitting. The light reflected from the luminance-enhanced film surface is inverted again with a reflective layer formed behind it, and then re-entered into the luminance-enhanced film, and then transmitted to the luminance-enhanced film by transmitting part or all of it as light in a predetermined polarization state. It is possible to improve the brightness by increasing the amount of light and increasing the amount of light that can be used for liquid crystal display and the like by supplying polarized light that is hardly absorbed by the polarizer. That is, when light is incident on the back side of the liquid crystal cell by a backlight or the like without using the brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost absorbed by the polarizer, and thus the polarizer. It does not penetrate through. That is, although it depends also on the characteristic of the polarizer used, about 50% of light is absorbed by a polarizer, and the quantity of light which can be used for a liquid crystal image display etc. decreases by that amount, and an image becomes dark. The brightness enhancement film is a reflection of the light having a polarization direction absorbed by the polarizer in the brightness enhancement film without incident to the polarizer, and then inverted again with a reflective layer formed behind it, and then re-incident to the brightness enhancement film Since only the polarization direction in which the polarization direction of the light reflected and inverted between the two becomes the polarization direction that can pass through the polarizer is transmitted through the luminance-enhancing film and is supplied to the polarizer, the image of the liquid crystal display device can be efficiently transmitted. Can be used for display to brighten the screen.

A diffusion plate may be formed between the luminance enhancing film and the reflective layer. The light in the polarized state reflected by the brightness enhancement film is directed toward the reflective layer or the like, but the diffuser plate uniformly diffuses the light passing therethrough and at the same time resolves the polarized state to become a non-polarized state. That is, the light in the natural light state is reflected toward the reflective layer or the like with the reflective layer interposed therebetween, and passes through the diffuser plate again and is reincident to the luminance enhancing film. Thus, by forming a diffuser plate between the luminance enhancing film and the reflective layer to restore the polarized light to the original natural light, while maintaining the brightness of the display screen and at the same time to reduce the unevenness of the display screen, to provide a uniform and bright screen can do. By forming such a diffuser plate, it is considered that the first incident light increases the repetition number of reflections moderately, thereby providing a uniform and bright display screen with the diffuser function of the diffuser plate.

The luminance-enhancing film is a cholesteric liquid crystal that exhibits a property of transmitting linearly polarized light of a predetermined polarization axis and reflecting other light, such as a multilayer laminate of a dielectric or a multilayer laminate of a thin film of different refractive index anisotropy. Suitable ones, such as those exhibiting a characteristic in which the circularly polarized light of either left rotation or right rotation is reflected and other light is transmitted, such as supporting the polymer alignment film or the alignment liquid crystal layer on the film substrate, can be used.

Therefore, in the luminance improvement film of the type which transmits the linearly polarized light of the said predetermined polarization axis, it can transmit efficiently, suppressing the absorption loss by a polarizing plate by making the transmitted light into a polarizing plate as it enters. On the other hand, in a luminance-enhancing film that transmits circularly polarized light, such as a cholesteric liquid crystal layer, the polarized light may be incident on a polarizer as it is, but the circularly polarized light is linearly polarized with a phase difference plate in order to suppress absorption loss. It is preferable to make it incident on a polarizing plate. In addition, by using a quarter wave plate as the retardation plate, circularly polarized light can be converted into linearly polarized light.

A retardation plate which functions as a quarter wave plate at a wide wavelength such as visible light is, for example, a phase difference layer exhibiting retardation characteristics different from that of a retardation plate functioning as a quarter wave plate with respect to pale light having a wavelength of 550 nm, for example. For example, it can obtain by the method of superimposing the retardation layer which functions as a 1/2 wave plate. Therefore, the phase difference plate arrange | positioned between a polarizing plate and a brightness enhancement film may consist of one layer or two or more phase difference layers.

Also, in the cholesteric liquid crystal layer, a reflection structure of a circular polarization in a wide wavelength range such as visible light can be obtained by arranging two or three or more layers in a combination structure having different reflection wavelengths. Transmissive circularly polarized light in a wide wavelength range can be obtained.

In addition, the polarizing plate may be formed by laminating a polarizing plate and two or three or more optical layers like the polarization splitting polarizing plate. Therefore, a reflective elliptical polarizing plate, a semi-transparent elliptical polarizing plate, etc. which combined the said reflective polarizing plate, a transflective polarizing plate, and a phase difference plate may be sufficient.

The retardation plate with a protective film, the pressure-sensitive adhesive retardation plate with a protective film, and the pressure-sensitive adhesive optical material with a protective film of the present invention can be suitably used for forming various image display devices such as liquid crystal display devices. The liquid crystal display device can be formed in a conventional manner. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an optical film, and an illumination system, if necessary, and mounting or driving the drive circuit according to the prior art. Also about a liquid crystal cell, what is arbitrary types, such as arbitrary types, such as a TN type, STN type, (pi) type, can be used, for example.

A suitable liquid crystal display device such as a liquid crystal display device in which an optical film is disposed on one or both sides of the liquid crystal cell, or a backlight or reflector used in an illumination system can be formed. In that case, the optical film according to the present invention can be provided on one or both sides of the liquid crystal cell. When forming an optical film in both sides, it may be the same or may differ. In forming a liquid crystal display device, for example, a diffuser plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, a backlight, or the like, at a suitable position, one layer or two or more layers may be used. Can be placed.

Next, the organic electroluminescent device (organic EL display device) will be described. The retardation plate with a protective film, the pressure-sensitive adhesive retardation plate with a protective film, and the pressure-sensitive adhesive optical material with a protective film of the present invention can also be applied to an organic EL display device. In general, an organic EL display device forms a light emitting body (organic electroluminescent light emitting body) by sequentially stacking a transparent electrode, an organic light emitting layer, and a metal electrode on a transparent substrate. Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, or such a light emitting layer and a perylene derivative. The structure which has various combinations, such as the laminated body of the electron injection layer which consists of these, or these laminated bodies of a hole injection layer, a light emitting layer, and an electron injection layer is known.

In the organic EL display device, holes and electrons are injected into the organic light emitting layer by applying a voltage to the transparent electrode and the metal electrode, and energy generated by the recombination of these holes and electrons excites the fluorescent material, and the excited fluorescent material is in a ground state. It emits light on the principle of emitting light when returning to. The mechanism of intermediate recombination is the same as that of a general diode, and as can be expected from this, the current and the light emission intensity show strong nonlinearity accompanied by rectification with respect to the applied voltage.

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

In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer also transmits light almost completely like the transparent electrode. As a result, the light incident on the surface of the transparent substrate during non-emission, and transmitted through the transparent electrode and the organic light emitting layer and reflected by the metal electrode again goes to the surface side of the transparent substrate, so that the display of the organic EL display device when viewed from the outside The surface looks like a mirror.

An organic EL display device comprising an organic electroluminescent emitter comprising a transparent electrode on the front side of an organic light emitting layer that emits light by application of a voltage and a metal electrode on the back side of the organic light emitting layer. A polarizing plate can be formed on the surface side of the film, and a phase difference plate can be formed between these transparent electrodes and the polarizing plate.

Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, the retardation plate and the polarizing plate do not visually recognize the mirror surface of the metal electrode from the outside. In particular, when the phase difference plate is constituted by a quarter wave plate, and the angle between the polarization direction of the polarizing plate and the phase difference plate is adjusted to π / 4, the mirror surface of the metal electrode can be completely shielded.

That is, external light incident on the organic EL display device transmits only the linearly polarized light component by the polarizing plate. This linearly polarized light is generally elliptically polarized by the retardation plate. In particular, the linearly polarized light becomes circularly polarized light when the retardation plate is a quarter wave plate and the angle formed between the polarizing plate and the retardation plate is? / 4.

The circularly polarized light penetrates the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, and then passes through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

Example

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The retardation plate and protective film which were used by the Example and the comparative example are shown below.

Retardation plate (alpha): The retardation plate of thickness 30micrometer which produced the casting film from the methylene chloride solution of polycarbonate resin (panlite, the Teijin Chemical Co., Ltd. make), and uniaxially stretched.

Retardation plate (beta): The retardation plate of thickness 40micrometer which produced the casting film from the methylene chloride solution of cyclic olefin resin (Aton, JSR Corporation make), and uniaxially stretched.

Retardation plate (gamma): The phase difference plate of thickness 40micrometer which produced the melt extrusion film of cyclic olefin resin (Zeonor, Nippon-Xeon company make), and uniaxially stretched.

Retardation plate δ: the following liquid crystal monomers:

The retardation plate of thickness 5micrometer produced by superposing | polymerizing and fixing in the state which orientated.

Protective film A: Protective film (protect tape # 6221F, Sekisui Chemical Co., Ltd. product) which has a 2-layered structure which makes polyethylene with a thickness of 40 micrometers as a base material layer, and uses an ethylene-vinyl acetate copolymer of 23 micrometers in thickness as an adhesive layer.

Protective film B: The protective film (RB-100, manufactured by Nitto Denko Co., Ltd.) which apply | coated the acrylic adhesive of thickness 5 micrometers to the base film which blended polypropylene and polyethylene of thickness 40 micrometers.

Protective film C: 2-ethylhexyl acrylate: acrylic acid = 100: 6 (weight ratio) was superposed | polymerized in toluene by the conventional method, and the copolymer (acryl polymer) was obtained. 5 parts of coronate L (made by Nippon Polyurethane) which is an isocyanate type crosslinking agent were mixed with respect to 100 weight part of this polymer solid content, and the adhesive solution was produced. A protective film produced by applying the obtained pressure-sensitive adhesive solution to a polyethylene terephthalate film (lumirror S27, manufactured by Toray) having a thickness of 38 μm so as to have a solid content of 20 μm, heating and drying at 120 ° C. for 3 minutes, and aging at 50 ° C. for 2 days.

(adhesiveness)

The adhesive force of each protective film is the adhesive force with respect to the to-be-adhered body actually bonded. The adhesive force of the first protective film is the adhesive force to the retardation plate, the adhesive force of the second protective film is the adhesive force to the base film of the first protective film. Adhesion was measured at a peel rate of 0.3 m / min, peel angle of 180 degrees, and room temperature (23 ° C.) after bonding a protective film (200 mm × 50 mm) to the adherend with a 20 N roller for one reciprocation (N / 50 mm). ) to be. The measurement was performed according to JIS Z 0237.

Example 1

After fixing the retardation plate α (200 mm × 300 mm) to the SUS plate with a temporary fixing tape, the protective film A was tensioned at a surface of the retardation plate α as a first protective film at 10 N / m and a bonding speed of 1 m / min. It bonded by the roll laminator. And the said protective film C was bonded by the said 1st protective film as the 2nd protective film by the method similar to the bonding method of a 1st protective film, and the phase difference plate with a protective film of 180 mm x 280 mm size was produced. Moreover, the retardation plate with a protective film was obtained by finally cutting 20 mm of temporary fixed tape parts etc. respectively.

Examples 2-5, Comparative Examples 1-3

In Example 1, the retardation plate with a protective film was produced like Example 1 except having changed the kind of retardation plate, a 1st protective film, and a 2nd protective film as shown in Table 1.

The following evaluation was performed about the retardation plate with a protective film obtained by the Example and the comparative example. The results are shown in Table 1.

(Adhesiveness)

About the produced retardation plate with a protective film, it evaluated whether the abnormality in which the protective film lifted or peeled off generate | occur | produced and curling generate | occur | produced. The case where there was no abnormality in appearance and the maximum curl height was 30 mm or less was referred to as "good". In other cases, the problem was described. All the examples were "good". In Comparative Examples 1 and 3, the maximum curl height exceeded 30 mm. In Comparative Example 2, the second protective film was removed.

(Peelability)

After fixing the four sides of the produced retardation plate with a protective film to a SUS board with 20 mm width double-sided tape, the cellophane tape was bonded to the 2nd protective film, and it peeled from the corner part. At this time, the case where all the protective films were easily peeled off was referred to as "good". The case where wrinkles and a crack generate | occur | produced in the retardation plate at the time of peeling was called "difficult." Moreover, when two peelings are required, it is described in Table 1.

(Workability / appearance)

The operation of lifting the produced retardation plate with a protective film horizontally with one hand was repeated 10 times. Thereafter, the protective film was peeled off to evaluate whether the retardation plate was folded, wrinkled, or cracked. The case where fold, wrinkles, and a crack did not generate | occur | produce in a retardation plate was called "good". When folds, wrinkles, and cracks occurred in the retardation plate, it is shown in Table 1. Moreover, since the peelability of the protective film was bad in Comparative Example 3, workability deteriorated.

In Table 1, PC: polycarbonate, PE: polyethylene, PE / PP: a mixture of polyethylene and polypropylene, PET: polyethylene terephthalate.

Industrial availability

The retardation plate used for the retardation plate with a protective film of this invention is used for various image display apparatuses, such as a liquid crystal display device, an organic electroluminescence display, and a PDP. The retardation plate with a protective film can provide a bonded or bonded product of the retardation plate without impairing workability and appearance in the production process.

Claims (8)

Two or more protective films having a pressure-sensitive adhesive layer on one side of the base film are sequentially bonded to the retardation plate, and the protective films other than the first protective film and the first protective film bonded to the retardation plate are applied to each adherend. Retardation plate with a protective film, characterized in that the adhesive force is different, the adhesive force of the first protective film is the smallest. The method of claim 1, The difference in the adhesive force between the first protective film bonded to the retardation plate and the second protective film adjacent to the retardation plate is 0.05 N / 50 mm or more. The method of claim 1, The adhesive force of the 1st protective film bonded to the retardation plate is 0.01-0.3N / 50mm, The retardation plate with a protective film characterized by the above-mentioned. The method of claim 1, A retardation plate with a protective film, wherein the base film of the first protective film bonded to the retardation plate is a polyolefin film, and the base film of the other protective film is a polyester film. The method of claim 1, Retardation plate with a protective film, characterized in that the thickness of the retardation plate is 1 to 60㎛. As a method of manufacturing the retardation plate with a protective film according to any one of claims 1 to 5, A protective film having an adhesive layer on one side of the base film, and preparing two or more protective films having different adhesion to each adherend, bonding the first protective film having the smallest adhesive strength to the retardation plate, and then applying the other protective film. Method for producing a retardation plate with a protective film, characterized in that the bonding as. The adhesive type retardation plate with a protective film which has an adhesive layer in the side which the protective film in the retardation plate with a protective film as described in any one of Claims 1-5 is not bonded. The adhesive type retardation plate with a protective film of Claim 7 is laminated | stacked with the other optical material through the adhesive layer, The adhesive optical material with a protective film characterized by the above-mentioned.

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