JP2008009156A - Method of forming adhesive optical film, adhesive optical film, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming an adhesive optical film having a discotic liquid crystal layer with a discotic liquid crystal compound oriented on one surface of a transparent base material film and an adhesive layer laminated on the discotic liquid crystal layer and capable of suppressing window frame unevenness in the lighting state of a back light. <P>SOLUTION: In the method of forming the adhesive optical film having a step for providing the adhesive layer on the discotic liquid crystal layer of the optical film having the discotic film formed on the one surface of the transparent base material film by orienting and hardening the discotic liquid crystal compound having a polymerizable unsaturated group, the discotic liquid crystal layer is irradiated with ultraviolet light and/or visible light before the step for providing the adhesive layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an adhesive optical film. The present invention also relates to an adhesive optical film obtained by the manufacturing method, and further to an image display device such as a liquid crystal display device, an organic EL display device, a CRT, and a PDP using the adhesive optical film.

  The adhesive optical film of the present invention has a discotic liquid crystal layer in which a discotic liquid crystal compound is aligned, and is useful as an optical compensation film for improving display contrast and viewing angle characteristics of display colors. A laminate of polarizers is useful as an elliptically polarizing plate with an optical compensation function.

  Liquid crystal display devices are rapidly marketed in watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, TVs, and the like. A liquid crystal display device visualizes a change in polarization state due to switching of liquid crystal, and a polarizer is used from the display principle. In particular, displays with higher brightness and higher contrast are required for applications such as TV, and light polarizers with higher brightness (high transmittance) and higher contrast (high polarization degree) have been developed and introduced. Yes.

  At present, the mainstream method of a general liquid crystal display device is a TFT-LCD using a TN liquid crystal. This method has advantages such as high response speed and high contrast. However, when the display of a panel using TN liquid crystal is viewed from an angle inclined from the normal direction, the contrast is remarkably lowered, and gradation inversion that reverses the gradation display occurs. It has the characteristic that the viewing angle is narrow. On the other hand, in applications such as large PC monitors and televisions, high contrast, wide viewing angle, and small display color change due to viewing angle are required. Therefore, when a TN mode TFT-LCD is used for such applications, a retardation film for compensating the viewing angle is indispensable.

  As this retardation film, a stretched birefringent polymer film has been conventionally used. Recently, it has been proposed to use an optical compensation film having an optically anisotropic layer formed of liquid crystalline molecules on a transparent support, instead of an optical compensation film made of a stretched birefringent film. Since liquid crystal molecules have various alignment forms, it has become possible to realize optical properties that cannot be obtained with conventional stretched birefringent polymer films by using liquid crystal molecules.

  As a viewing angle compensation retardation film as described above, for example, a wide view film manufactured by Fuji Photo Film Co., Ltd. using a discotic liquid crystal having negative refractive index anisotropy has been proposed (Patent Document 1, Patent Document 2). This retardation film has a discotic liquid crystal layer having an optical axis inclined and oriented on one side of a transparent substrate film. This retardation film is mainly intended to improve viewing angle characteristics in a voltage application state for black display. That is, in a voltage application state, the liquid crystal molecules in the liquid crystal cell exhibit positive refractive index anisotropy having an optical axis inclined from the glass substrate. In order to compensate for the retardation due to the refractive index anisotropy, the retardation film uses a liquid crystalline molecule having an optical axis inclined from the normal direction of the film and having negative refractive index anisotropy.

  In the retardation film for compensating the viewing angle, a polarizer is laminated on the transparent substrate film and used as an elliptically polarizing plate, while an adhesive layer is laminated on the discotic liquid crystal layer. An adhesive optical film such as a retardation film or an elliptically polarizing plate on which the pressure-sensitive adhesive layer is laminated is used by being bonded to a liquid crystal cell or the like via the pressure-sensitive adhesive layer. However, when the above-mentioned retardation film or elliptically polarizing plate for viewing angle compensation is combined with a liquid crystal cell or the like via an adhesive layer together with a backlight (lighted state), a liquid crystal display There is a problem that unevenness (hereinafter referred to as window frame unevenness) occurs in the vicinity of the frame of the apparatus, and visibility is lowered. In particular, when the temperature is increased or the size of the liquid crystal display device is increased, the window frame unevenness becomes remarkable.

JP-A-8-95032 Japanese Patent No. 2767382

  The present invention is an adhesive optical film having a discotic liquid crystal layer in which a discotic liquid crystal compound is aligned on one side of a transparent substrate film, and further having an adhesive layer laminated on the discotic liquid crystal layer. Then, it aims at providing the manufacturing method of the adhesive optical film which can suppress the window frame nonuniformity in the lighting state of a backlight.

  Another object of the present invention is to provide a pressure-sensitive adhesive optical film obtained by the above production method, and further to provide an image display device using the pressure-sensitive adhesive optical film.

  The present inventors have intensively studied to solve the above-mentioned problems. As a result, they have found that the above object can be achieved by the following method for producing an adhesive optical film, and have completed the present invention.

That is, the present invention provides a pressure-sensitive adhesive on the discotic liquid crystal layer of an optical film having a discotic liquid crystal layer formed by orientation and curing of a discotic liquid crystal compound having a polymerizable unsaturated group on one side of a transparent substrate film. In the method for producing an adhesive optical film having a step of providing a layer,
The present invention relates to a method for producing a pressure-sensitive adhesive optical film characterized by irradiating a discotic liquid crystal layer with ultraviolet light and / or visible light before the step of providing a pressure-sensitive adhesive layer.

  The method for producing an adhesive optical film may include a step of providing an undercoat layer before the step of providing an adhesive layer after irradiation with ultraviolet light and / or visible light.

In the method for producing the pressure-sensitive adhesive optical film, it is preferable that the irradiation light includes ultraviolet light and the integrated light amount at a wavelength of 350 nm is 10 to 10,000 mJ / cm ² .

  In the method for producing an adhesive optical film, it is preferable that one side of the transparent substrate film on which the discotic liquid crystal layer is formed is rubbed or an alignment film is formed.

  In the method for producing the pressure-sensitive adhesive optical film, as the optical film, one in which a polarizer is laminated on one side of a transparent substrate film on the side where a discotic liquid crystal layer is not formed can be used.

  In the method for producing the pressure-sensitive adhesive optical film, after the step of providing the pressure-sensitive adhesive layer, a step of laminating a polarizer on one side of the transparent substrate film on the side where the discotic liquid crystal layer is not formed can be included.

  The present invention also relates to an adhesive optical film obtained by the production method.

  The present invention also relates to an image display device using at least one adhesive optical film. The pressure-sensitive adhesive optical film of the present invention is used in combination of one or more sheets depending on various usage modes of an image display device such as a liquid crystal display device.

  The present inventors have found that the discotic liquid crystal layer that functions as an optical compensation layer is formed by the orientation and curing of a discotic liquid crystal compound having a polymerizable unsaturated group. Assuming that the unsaturated group remains, the front phase difference value becomes larger in the window frame part than in the center part when the backlight is turned on for a long time due to the influence of the residual polymerizable unsaturated group. I thought this might be the cause of window frame unevenness.

  Therefore, in the method for producing an adhesive optical film of the present invention, before the adhesive layer is provided on the discotic liquid crystal layer provided on one side of the transparent substrate film, ultraviolet light and / or visible light is applied to the discotic liquid crystal layer. Irradiation reduced the polymerizable unsaturated groups remaining in the discotic liquid crystal layer. Thereby, by suppressing the influence of the polymerizable unsaturated group remaining in the discotic liquid crystal layer, it is possible to suppress window frame unevenness due to an increase in front phase difference value in the window frame portion. In addition, by irradiating the discotic liquid crystal layer with ultraviolet light and / or visible light, the surface hardness of the discotic liquid crystal layer is increased, and the improvement of the surface hardness also has the effect of suppressing window frame unevenness. It is done.

  Since window frame unevenness is likely to occur when the liquid crystal display device is large, the method for producing an adhesive optical film of the present invention is particularly effective when producing a large adhesive optical film. Further, since window frame unevenness is likely to occur when the environmental temperature is high, the method for producing an adhesive optical film of the present invention is particularly effective when producing an adhesive optical film used in a high temperature environment.

  The present invention will be described below with reference to the drawings. As shown in FIG. 1, the optical film of the present invention has a discotic liquid crystal layer 3 on one side of a transparent substrate film 1. The discotic liquid crystal layer 3 is formed by alignment and curing of a discotic liquid crystal compound having a polymerizable unsaturated group. In FIG. 1, the case where the alignment film 2 is provided between the transparent substrate film 1 and the discotic liquid crystal layer 3 is illustrated, but instead of the alignment film 2, one side of the transparent substrate film 1 is rubbed. Can be used.

  In FIG. 1 (1), the surface of the discotic liquid crystal layer 3 is irradiated with ultraviolet light and / or visible light. Thereby, the remaining polymerizable unsaturated groups of the discotic liquid crystal layer 3 are reduced and the hardness is increased. In addition, although irradiation light is irradiated from the discotic liquid crystal layer 3 side in FIG. 1 (1), irradiation can also be performed from the transparent base film side.

  Next, after providing the undercoat layer 4 as shown in FIG. 1 (2), the pressure-sensitive adhesive layer 5 is provided as shown in FIG. 1 (3) to produce the pressure-sensitive adhesive optical film of the present invention. In addition, the process of providing the undercoat layer 4 shown in FIG. 1 (2) is arbitrary, and without providing the undercoat layer 4, as shown in FIG. 1 (3 '), the pressure-sensitive adhesive layer is formed on the discotic liquid crystal layer 3. 5 can be provided.

  FIG. 2 shows an optical film having a discotic liquid crystal layer 3 on one side of a transparent substrate film 1 with an alignment film 2 interposed therebetween, and the transparent substrate film 1 on the side where the discotic liquid crystal layer 3 is not formed. This is a case where a polarizer 6 and then a transparent protective film 7 are laminated on one side. In FIG. 2, the transparent substrate film 1 also serves as a transparent protective film for the polarizer 6. As shown in FIG. 2, the optical film having a polarizing plate can be subjected to the same steps as in FIG. 1 to reduce the remaining polymerizable unsaturated groups of the discotic liquid crystal layer 3 and increase the hardness. Can do.

  FIG. 3 shows a polarizer 6 and then a transparent protective film 7 on one side of the transparent substrate film 1 on the side where the discotic liquid crystal layer 3 is not formed in the adhesive optical film obtained in FIG. In this case, an optical film having a polarizing plate is manufactured by laminating layers. In FIG. 3, the transparent substrate film 1 also serves as a transparent protective film for the polarizer 6.

  In the present invention, an optical film having a discotic liquid crystal layer 3 is used on one side of the transparent substrate film 1.

  Various transparent materials can be used as the transparent substrate film. 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, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the transparent substrate film.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing a thermoplastic resin having unsubstituted phenyl and a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used.

  Although the thickness of a transparent base film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin film property. In particular, 5 to 200 μm is preferable.

  Moreover, it is preferable that a transparent base film has as little coloring as possible. Therefore, Rth = (nx−nz) · d (where nx is the refractive index in the slow axis direction in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a direction retardation of −90 nm to +75 nm is preferably used. By using a film having a retardation value (Rth) in the thickness direction of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the transparent substrate film can be almost eliminated. The thickness direction retardation (Rth) is more preferably -80 nm to +60 nm, and particularly preferably -70 nm to +45 nm.

  The transparent substrate film is preferably a cellulose polymer such as triacetyl cellulose or a norbornene polymer from the viewpoints of polarization characteristics and durability. In particular, a cellulose polymer such as triacetylcellulose is preferable.

  The discotic liquid crystal layer is formed by alignment and curing of a discotic liquid crystal compound having a polymerizable unsaturated group. The discotic liquid crystal layer is useful as an optical compensation layer, and can improve the viewing angle, contrast, brightness, and the like. The discotic liquid crystal compound has a polymerizable unsaturated group, and the discotic liquid crystal layer is formed by aligning and curing the compound. The discotic liquid crystal layer is preferably one in which a discotic liquid crystal compound is tilted. The thickness of the discotic liquid crystal layer is usually about 0.5 to 10 μm.

  The discotic liquid crystal compound has a negative refractive index anisotropy (uniaxiality). Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives and B.I. Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), such as azacrown and phenylacetylene macrocycles, etc., which are generally used as a mother nucleus at the center of a molecule, and are a linear alkyl group or alkoxy group, substituted A structure in which a benzoyloxy group or the like is radially substituted as a straight chain thereof exhibits liquid crystallinity and includes what is generally called a discotic liquid crystal. However, the molecule itself is not limited to the above description as long as the molecule itself has negative uniaxiality and can give a certain orientation. In the present invention, the discotic liquid crystal compound has a polymerizable unsaturated group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.) that undergoes a curing reaction with heat, light, or the like. Note that the discotic liquid crystal layer does not necessarily need to be a final product, and includes a liquid crystal layer that has been polymerized or cross-linked by the reaction of a polymerizable unsaturated group to increase the molecular weight and lose liquid crystallinity.

  In addition, discotic liquid crystal compounds are optical molecules such as reaction products of discotic liquid crystals that no longer exhibit liquid crystallinity due to reactions with various discotic liquid crystal compounds and other low molecular compounds and polymers. In general, it means all compounds having negative uniaxiality.

  For the alignment treatment of the discotic liquid crystal, the surface of the transparent substrate film is rubbed or an alignment film is used. Examples of the alignment film include an inorganic oblique deposition film or an alignment film obtained by rubbing a specific organic polymer film. There is a thin film in which isomerization is caused by light, such as an LB film made of an azobenzene derivative, and molecules are uniformly arranged with directionality. Examples of the organic alignment film include polyimide films, and organic polymer films that form a hydrophobic surface such as alkyl chain-modified poval, polyvinyl butyral, and polymethyl methacrylate. In addition, a SiO oblique vapor deposition film is an example of the inorganic oblique vapor deposition film.

  The discotic liquid crystal compound is tilted and aligned. For example, a discotic liquid crystal compound (polymerizable liquid crystal compound) is applied to form a tilted alignment state by forming an alignment film on a transparent substrate film. Thereafter, a method such as fixing by irradiation with light such as ultraviolet light or heat can be used. It is also possible to form the discotic liquid crystal on another alignment substrate by tilting and then transferring it onto a transparent support using an optically transparent adhesive or pressure sensitive adhesive. is there.

  As such a discotic liquid crystal layer, those described in Patent Documents 1 and 2 are preferably used. A wide-view film manufactured by Fuji Photo Film Co., Ltd. is one in which such a discotic liquid crystal inclined alignment layer is formed on a cellulosic polymer film.

  In the present invention, the discotic liquid crystal layer is irradiated with ultraviolet light and / or visible light. Residual polymerizable unsaturated groups are reduced by irradiation with ultraviolet light and / or visible light. Further, the surface hardness of the discotic liquid crystal layer is increased. Irradiation is preferably performed so that the hardness of the discotic liquid crystal layer is increased by about 0.02 to 0.12 GPa by the irradiation. The hardness of the discotic liquid crystal layer varies depending on the material used for forming the discotic liquid crystal layer, but the hardness of the discotic liquid crystal layer before irradiation is usually preferably about 0.11 to 0.16 GPa. The hardness of the discotic liquid crystal layer after the irradiation is preferably about 0.17 to 0.24 GPa.

For the remaining polymerizable unsaturated groups, the absorbance ratio (811 cm ⁻¹ / 1510 cm ⁻¹ ) of IR spectrum 1510 cm ⁻¹ (derived from aromatic) and 811 cm ⁻¹ (derived from carbon-carbon double bond) is reduced. This can be confirmed. The irradiation is preferably performed so that the absorbance ratio of the discotic liquid crystal layer is reduced by about 0.04 to 0.18 by the irradiation. The absorbance ratio of the discotic liquid crystal layer before irradiation is usually preferably about 0.23 to 0.30, and the absorbance ratio of the discotic liquid crystal layer after irradiation is usually 0.12 to 0.22. It is preferably about 0.19.

As the irradiation light, ultraviolet light and / or visible light is used. In general, the cumulative amount of irradiation light is preferably 10 to 10,000 mJ / cm ² . The surface treatment of the discotic liquid crystal layer can be effectively performed with the integrated light quantity in this range.

  The irradiation light preferably includes ultraviolet light, and the integrated light quantity at a wavelength of 350 nm is preferably in the above range. When ultraviolet light is included, it is preferable from the viewpoint of shortening the irradiation time and improving efficiency.

  The discotic liquid crystal layer irradiated with the ultraviolet light and / or visible light is provided with an adhesive layer, but an undercoat layer can be provided before the step of providing the adhesive layer.

  Examples of the material for forming the undercoat layer include urethane (polyisocyanate), polyester, acrylic, polyamide, melamine, olefin, polystyrene, epoxy, phenol, isocyanurate, polyvinyl acetate, Examples thereof include materials such as silane coupling agents. The undercoat layer can improve adhesion with the pressure-sensitive adhesive layer. The forming material may be imparted with other functions by adding a crosslinking agent for crosslinking and curing or a functional additive such as an antistatic agent.

  As a method for laminating the undercoat layer, various laminating methods can be appropriately selected according to the type of the material for forming the undercoat layer. For example, a method such as extrusion lamination or dry lamination by film formation, or a method of drying and solidifying after coating can be employed. The thickness of the undercoat layer is usually 1 μm or less, preferably 10 to 500 nm.

  The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited, and various pressure-sensitive adhesives such as rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives can be used. A good acrylic pressure-sensitive adhesive is generally used.

  The acrylic pressure-sensitive adhesive has an acrylic polymer having a main skeleton of an alkyl (meth) acrylate monomer unit as a base polymer. (Meth) acrylate refers to acrylate and / or methacrylate, and (meth) of the present invention has the same meaning. The average carbon number of the alkyl group of the alkyl (meth) acrylate constituting the main skeleton of the acrylic polymer is about 1 to 12, and specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (Meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, etc. can be exemplified, and these are used alone or in combination. it can. Among these, alkyl (meth) acrylates having 1 to 9 carbon atoms in the alkyl group are preferable.

  In the acrylic polymer, one or more kinds of various monomers are introduced by copolymerization for the purpose of improving adhesiveness and heat resistance. Specific examples of such copolymerization monomers include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid 6 Hydroxyl group-containing monomers such as hydroxyhexyl, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate Carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; acid anhydrides such as maleic anhydride and itaconic anhydride Monomer-containing monomer; Caprolac of acrylic acid Adducts such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid, etc. And sulfonic acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate.

  Moreover, a nitrogen-containing vinyl monomer is mention | raise | lifted. For example, maleimide, N-cyclohexylmaleimide, N-phenylmaleimide; N-acryloylmorpholine; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-hexyl ( (N-substituted) such as (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropane (meth) acrylamide ) Amide monomer; aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, 3- (3- Pyridinyl) propyl (meth) acrelane (Meth) acrylic acid alkylaminoalkyl monomers such as (meth) acrylic acid methoxyethyl, (meth) acrylic acid alkoxyalkyl monomers such as ethoxyethyl; N- (meth) acryloyloxymethylene succinimide, Succinimide monomers such as N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyoctamethylene succinimide, N-acryloylmorpholine, and the like are also examples of monomers for modification.

  Furthermore, vinyl acetate, vinyl propionate, N-vinyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, N-vinyl carboxylic acid amide , Vinyl monomers such as styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; (meth) acrylic Polyethylene glycol acid, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, methoxypolypropylene (meth) acrylate Glycol acrylic ester monomers such as recall; (meth) acrylic acid tetrahydrofurfuryl, fluorine (meth) acrylate, silicone (meth) acrylate and acrylic acid ester monomers such as 2-methoxyethyl acrylate, etc. may also be used.

  Among these, carboxyl group-containing monomers such as acrylic acid are preferably used from the viewpoint of adhesion to the liquid crystal cell and adhesion durability.

  Although the ratio of the copolymerization monomer in the acrylic polymer is not particularly limited, it is preferably about 0.1 to 10% in weight ratio.

  The average molecular weight of the acrylic polymer is not particularly limited, but the weight average molecular weight is preferably about 300,000 to 2.5 million. The acrylic polymer can be produced by various known methods. For example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method, or a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo and peroxide initiators can be used. The reaction temperature is usually about 50 to 80 ° C., and the reaction time is 1 to 8 hours. Among the above production methods, the solution polymerization method is preferable, and ethyl acetate, toluene and the like are generally used as the solvent for the acrylic polymer. The solution concentration is usually about 20 to 80% by weight.

  Examples of the base polymer of the rubber adhesive include natural rubber, isoprene rubber, styrene-butadiene rubber, recycled rubber, polyisobutylene rubber, styrene-isoprene-styrene rubber, and styrene-butadiene-styrene rubber. Etc. Examples of the base polymer of the silicone-based pressure-sensitive adhesive include dimethylpolysiloxane and diphenylpolysiloxane, and those base polymers into which a functional group such as a carboxyl group is introduced can also be used.

  The pressure-sensitive adhesive is preferably a pressure-sensitive adhesive composition containing a crosslinking agent. Examples of the polyfunctional compound that can be blended in the pressure-sensitive adhesive include organic crosslinking agents and polyfunctional metal chelates. Examples of the organic crosslinking agent include an epoxy crosslinking agent, an isocyanate crosslinking agent, and an imine crosslinking agent. As the organic crosslinking agent, an isocyanate crosslinking agent is preferable. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. can give. Examples of the atom in the organic compound that is covalently bonded or coordinated include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

  The blending ratio of the base polymer such as the acrylic polymer and the crosslinking agent is not particularly limited, but usually about 0.01 to 6 parts by weight of the crosslinking agent (solid content) is preferable with respect to 100 parts by weight of the base polymer (solid content). Furthermore, about 0.1-3 weight part is preferable.

  Furthermore, the pressure-sensitive adhesive may include a tackifier, a plasticizer, glass fiber, glass beads, metal powder, other inorganic powders, a pigment, a colorant, a filler, an antioxidant, if necessary. Various additives may be used as appropriate, such as an agent, an ultraviolet absorber, a silane coupling agent, and the like without departing from the object of the present invention. Moreover, it is good also as an adhesive layer etc. which contain microparticles | fine-particles and show light diffusibility.

  The pressure-sensitive adhesive layer is formed by laminating on the discotic liquid crystal layer or the undercoat layer. The forming method is not particularly limited, and examples thereof include a method of applying and drying a pressure-sensitive adhesive (solution), a method of transferring with a release sheet provided with a pressure-sensitive adhesive layer, and the like. As a coating method, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, or a spray method can be adopted. The pressure-sensitive adhesive layer (dry film thickness) is not particularly limited in thickness, but is preferably about 10 to 40 μm.

  In the pressure-sensitive adhesive optical film of the present invention, window frame unevenness tends to occur when the pressure-sensitive adhesive layer is thin. Therefore, the pressure-sensitive adhesive optical film of the present invention is particularly suitable when the thickness of the pressure-sensitive adhesive layer is as thin as 5 to 40 μm, further 5 to 25 μm. In addition, in the adhesive optical film of this invention, when an adhesive layer is hard, a window frame nonuniformity tends to arise.

  As a constituent material of the release sheet, paper, polyethylene, polypropylene, polyethylene terephthalate and other synthetic resin films, rubber sheets, paper, cloth, non-woven fabric, nets, foam sheets and metal foils, and appropriate thin leaf bodies such as laminates thereof Etc. In order to improve the peelability from the pressure-sensitive adhesive layer, the surface of the release sheet 4 may be subjected to a peeling treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment as necessary.

  As a constituent material of the release sheet, paper, polyethylene, polypropylene, polyethylene terephthalate and other synthetic resin films, rubber sheets, paper, cloth, non-woven fabric, nets, foam sheets and metal foils, and appropriate thin leaf bodies such as laminates thereof Etc. In order to improve the peelability from the pressure-sensitive adhesive layer, the surface of the release sheet may be subjected to a low-adhesive release treatment such as silicone treatment, long-chain alkyl treatment, and fluorine treatment as necessary.

  As shown in FIG. 2, the optical film of the present invention has a polarizer 6 and then a transparent protective film 7 laminated on one side of the transparent substrate film 1 on the side where the discotic liquid crystal layer 3 is not formed. Can be used. Also, as shown in FIG. 3, a polarizer 6 and then a transparent protective film 7 are laminated on one side of the transparent base film 1 on the side where the discotic liquid crystal layer 3 is not formed. The optical film which has can be manufactured.

  The polarizer 6 is bonded to the transparent substrate film 1 using an adhesive. 2 and 3, the transparent base film 1 also serves as a transparent protective film for the polarizer 6, but the transparent base film 1 has a transparent protective film on one or both sides of the polarizer. A polarizing plate can also be laminated.

  The polarizer is not particularly limited, and various types can be used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared by, for example, dying polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. The transparent protective film can use the same material as the transparent substrate film. The same applies to the thickness.

  The transparent substrate film and the transparent protective film may use the same polymer material or different polymer materials.

  The polarizer, the transparent substrate film, and the transparent protective film are usually in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester. In addition, in bonding of a polarizer, a transparent base film, and a transparent protective film, an activation process can be performed to a transparent base film and a transparent protective film. Various methods can be employed for the activation treatment, for example, saponification treatment, corona treatment, low-pressure UV treatment, plasma treatment, or the like. The activation treatment is effective particularly when the transparent substrate film is triacetyl cellulose, norbornene resin, polycarbonate, polyolefin resin, or the like.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a treatment for the purpose of hard coat layer, antireflection treatment, sticking prevention, diffusion or antiglare.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection 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 conventional art. Further, the sticking prevention treatment is performed for the purpose of preventing adhesion between adjacent layers of other members.

  Anti-glare treatment is applied for the purpose of preventing external light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by sandblasting or embossing. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a method or a compounding method of transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles and organic fine particles (including beads) made of a crosslinked or uncrosslinked polymer are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The anti-glare layer may also serve as a diffusion layer (such as a visual enlargement function) for diffusing the light transmitted through the polarizing plate to enlarge vision.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  In addition to the optical film in which the polarizing plate is laminated, as an optical film used for the pressure-sensitive adhesive optical film of the present invention, an optical layer used for forming an image display device such as a liquid crystal display device may be laminated. it can. For example, an optical layer that may be used for forming a liquid crystal display device such as a reflection plate, an anti-transmission plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), and a brightness enhancement film. can give. These can be used alone as an optical film, or can be laminated on the polarizing plate for practical use and used as one layer or two or more layers.

  In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a semi-transmissive reflecting plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated with a polarizing plate, or A polarizing plate obtained by further laminating a brightness enhancement film on the polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. In addition, the transparent protective film may contain fine particles to form a surface fine concavo-convex structure, and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. Moreover, the protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it and light and dark unevenness can be further suppressed. The reflective layer of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film is formed by, for example, applying metal to the surface of the transparent protective layer by an appropriate method such as a vacuum deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of attaching directly to the screen.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device of a type that displays an image using a built-in power source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate can be used to form liquid crystal display devices that can save energy when using a light source such as a backlight in a bright atmosphere and can be used with a built-in power supply even in a relatively dark atmosphere. It is.

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

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function.

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene resin, or binary, ternary copolymers, graft copolymers, Examples include blends. These polymer materials become an oriented product (stretched film) by stretching or the like.

  Examples of the liquid crystal polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. . Specific examples of the main chain type liquid crystal polymer include a nematic alignment polyester liquid crystal polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded at a spacer portion that imparts flexibility. Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment-providing para-substitution through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogenic part composed of a cyclic compound unit. These liquid crystal polymers are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment treatment surface such as a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or an oblique deposition of silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as for the purpose of compensating for coloring, vision, etc. due to birefringence of various wave plates and liquid crystal layers, and may be two or more types. It may be one in which retardation plates are stacked and optical characteristics such as retardation are controlled.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. An optical film such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and accordingly, the amount of light that can be used for liquid crystal image display or the like is reduced and the image becomes dark. The brightness enhancement film reflects light that has a polarization direction that is absorbed by the polarizer without being incident on the polarizer, and is reflected by the brightness enhancement film, and then inverted through a reflective layer or the like provided behind the brightness enhancement film. The brightness enhancement film transmits only the polarized light in which the polarization direction of the light reflected and inverted between the two is allowed to pass through the polarizer. Since the light is supplied to the polarizer, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  A diffusion plate may be provided between the brightness enhancement film and the reflective layer. The polarized light reflected by the brightness enhancement film is directed to the reflective layer or the like, but the installed diffuser plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarized state and becomes a non-polarized state. That is, the light in the natural light state is directed toward the reflection layer or the like, reflected through the reflection layer or the like, and again passes through the diffusion plate and reenters the brightness enhancement film. In this way, by providing a diffuser plate that returns polarized light to the original natural light between the brightness enhancement film and the reflective layer, the brightness of the display screen is maintained, and at the same time, the brightness of the display screen is reduced and uniform. Can provide a bright screen. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropies. Such as an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate things, such as a thing, can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that transmits circularly polarized light such as a cholesteric liquid crystal layer, it can be incident on a polarizer as it is, but from the point of suppressing absorption loss, the circularly polarized light is converted into linearly polarized light through a retardation plate. It is preferably incident on the polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate at a wide wavelength in the visible light region or the like exhibits, for example, a retardation plate that functions as a quarter-wave plate for light-colored light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method in which a phase difference layer, for example, a phase difference layer that functions as a half-wave plate is superimposed. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, a cholesteric liquid crystal layer having a reflection structure that reflects circularly polarized light in a wide wavelength range such as a visible light range can be obtained by combining two or more layers with different reflection wavelengths to form an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or more optical layers as in the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-described reflective polarizing plate or semi-transmissive polarizing plate and a retardation plate are combined may be used.

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target phase difference characteristic.

  In addition, each layer such as an optical film or an adhesive layer of the pressure-sensitive adhesive optical film of the present invention includes, for example, an ultraviolet ray such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound. What gave the ultraviolet absorptivity by systems, such as a system processed with an absorber, may be used.

  The pressure-sensitive adhesive optical film of the present invention can be preferably used for forming various image display devices such as liquid crystal display devices. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an adhesive optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no particular limitation except that an adhesive optical film is used. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which an adhesive optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. In that case, the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When optical films are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. The optical film (polarizing plate or the like) of the present invention can also be applied to an organic EL display device. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). 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 and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light-emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light-emitting layer, and electron injection layer is known. It has been.

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

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are 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 transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode 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, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wavelength plate and the angle formed by the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light 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.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight.

<Optical film>
A wide view (WV) film manufactured by Fuji Photo Film Co., Ltd. was used. The WV film had a discotic liquid crystal layer in which discotic liquid crystal molecules were tilted and aligned on a cellulose polymer film that was a transparent substrate film.

  The WV film was separated into an inclined alignment layer of discotic liquid crystal molecules, and the characteristics at λ = 590 nm were measured with KOBRA-21ADH manufactured by Oji Scientific Instruments. The in-plane maximum refractive index was nx, the refractive index in the direction perpendicular to the direction having the in-plane maximum refractive index was ny, and the refractive index in the thickness direction was nz. The thickness was d. The transparent support had Δnd = (nx−ny) × d = 12 nm and Rth = (nx−nz) × d = 100 nm. On the other hand, the tilted alignment layer measured the phase difference by changing the incident angle from −50 ° to 50 ° in the direction in which the optical axis is tilted. As a result, Δnd = 30 nm, Rth = 150 nm, and average tilt angle θ = 17 °. Met.

  After the saponification treatment of the transparent substrate film side of the WV film, the saponification treatment surface and a polyvinyl alcohol polarizer (manufactured by Nitto Denko Corporation, SEG-5424WL) are pasted with a polyvinyl alcohol adhesive. Combined. On the other hand, a transparent protective film (triacetyl cellulose film, thickness 80 μm) is bonded to the other surface of the polarizer with the same polyvinyl alcohol-based adhesive as described above, and an optical film having a polarizing plate (with a viewing angle expansion film) Polarizing plate) was prepared.

<Undercoat layer>
An undercoat agent prepared by adjusting acrylic acid ester (manufactured by Nippon Shokubai Co., Ltd., Poliment NK380) to toluene so that the solid content was 2% was used.

<Adhesive layer>
As a base polymer, a solution (solid content 30) containing an acrylic polymer having a weight average molecular weight of 2 million consisting of a copolymer of butyl acrylate: acrylic acid: 2-hydroxyethyl acrylate = 100: 5: 0.1 (weight ratio) %) Was used. Viscosity adjustment of 4 parts of Coronate L manufactured by Nippon Polyurethane Co., Ltd., an isocyanate-based polyfunctional compound, and 100 parts of polymer solids and 0.5 part of additive (manufactured by Shin-Etsu Silicone, KBM403) A solvent (ethyl acetate) was added to prepare an adhesive solution (solid content 12%). The pressure-sensitive adhesive solution was applied on a release sheet (polyethylene terephthalate base material: Diafoil MRF38, manufactured by Mitsubishi Chemical Polyester) so that the thickness after drying was 25 μm, and then dried in a hot air circulation oven. An adhesive layer was formed.

Example 1
(Irradiation treatment)
The discotic liquid crystal layer of the optical film having the polarizing plate was irradiated with ultraviolet rays (illuminance 40 mW / cm ² , integrated light amount 300 mJ / cm ² ) using an ultraviolet irradiation device (manufactured by CSUN, UVC-321AM). This ultraviolet irradiation was performed 10 times (accumulated light amount 3000 mJ / cm ² ). The integrated light amount is an integrated light amount at a wavelength of 350 nm.

(Preparation of adhesive optical film)
After applying the primer to the surface of the discotic liquid crystal layer subjected to the irradiation treatment with a wire bar to form an undercoat layer (thickness 20 nm), a release sheet on which an adhesive layer is formed is pasted. In addition, an adhesive optical film was produced.

Comparative Example 1
In Example 1, an adhesive optical film was produced in the same manner as in Example 1 except that the irradiation treatment was not performed.

  The following evaluations were performed on the discotic liquid crystal layers before and after the irradiation treatment and on the obtained adhesive optical film. The results are shown in Table 1.

<Hardness>
The surface hardness of the discotic liquid crystal layer was measured by the following apparatus.
Analyzer: Nanoindenter (MTS, SA2)
Indenter: Triangular pyramid type diamond indenter A diamond indenter is pushed from the discotic liquid crystal layer side, and the hardness is measured from the stress applied to the indenter at that time. The hardness at an indentation depth of 100 nm is measured. The measurement was performed 10 times, and the average value was described.

<Remaining polymerizable unsaturated group: Absorbance ratio>
The polymerizable unsaturated group remaining in the discotic liquid crystal layer was measured by the following apparatus.
Analyzer: FT-IR (manufactured by Thermo Nicolet, Magna 750)
Measuring method: ATR method IR crystal: ZnSe
Incident angle: 45 °
Measurement wavelength: 4000 to 650 cm ⁻¹
Integration count: 128 times Detector: DTGS
The resulting 1510 cm of IR scan Bae spectrum ^-1 (derived from aromatic ring) and 811cm ^-1 - was calculated absorbance ratio of (carbon-carbon double bond ^{derived) (811cm -1 / 1510cm -1)} .

<Mura>
It arrange | positioned on a backlight so that the adhesive layer side of the obtained adhesive optical film (size: 300 mm x 220 mm) might become an upper side. The backlight was turned on in an atmosphere at 80 ° C., and whether or not window frame unevenness occurred in the peripheral portion (within 10 mm from the edge) of the optical film was visually evaluated according to the following criteria. The lighting time was confirmed for 100 hours, 170 hours, and 340 hours.
○: No unevenness in the periphery.
X: There is unevenness in the peripheral part.

It is an example which shows the flow of the manufacturing method of the adhesive optical film of this invention. It is an example which shows the flow of the manufacturing method of the adhesive optical film of this invention. It is an example which shows the flow of the manufacturing method of the adhesive optical film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base film 2 Alignment film 3 Discotic liquid crystal layer 4 Undercoat layer 5 Adhesive layer 6 Polarizer 7 Transparent protective film

Claims (8)

A step of providing an adhesive layer on the discotic liquid crystal layer of an optical film having a discotic liquid crystal layer formed by orientation and curing of a discotic liquid crystal compound having a polymerizable unsaturated group on one side of a transparent substrate film. In the method for producing an adhesive optical film having:
A method for producing an adhesive optical film, wherein the discotic liquid crystal layer is irradiated with ultraviolet light and / or visible light before the step of providing the adhesive layer.   The method for producing a pressure-sensitive adhesive optical film according to claim 1, further comprising a step of providing an undercoat layer before the step of providing the pressure-sensitive adhesive layer after irradiation with ultraviolet light and / or visible light. Irradiation light comprises ultraviolet light, the accumulated amount of light at a wavelength of 350nm The method for producing a pressure-sensitive adhesive optical film according to claim 1 or 2, wherein it is a 10 to 10000 mJ / cm ^2.   The pressure-sensitive adhesive mold according to any one of claims 1 to 3, wherein one surface of the transparent substrate film on which the discotic liquid crystal layer is formed is rubbed or an alignment film is formed. Manufacturing method of optical film.   The optical film is a pressure-sensitive adhesive optical film according to any one of claims 1 to 4, wherein a polarizer is laminated on one side of the transparent base film on the side where the discotic liquid crystal layer is not formed. Production method.   5. The method according to claim 1, further comprising a step of laminating a polarizer on one side of the transparent substrate film on the side where the discotic liquid crystal layer is not formed after the step of providing the pressure-sensitive adhesive layer. The manufacturing method of the adhesion type optical film of description.   A pressure-sensitive adhesive optical film obtained by the production method according to claim 1.   An image display device using at least one adhesive optical film according to claim 7.

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