JP2005096298A - Optical film and optical display device equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film suppressing the occurrence of an interference fringe, and an optical display device equipped with it. <P>SOLUTION: This optical film comprises a transparent base material layer and the antistatic layer formed thereon, and the occurrence of the interference fringe is suppressed by controlling the difference between the refractive index of the transparent base material layer and that of the antistatic layer to 0.03 or below, preferably 0.01 or below. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical film and an optical display device including the optical film.

Conventionally, plate-like transparent materials such as glass and plastic have been used for displays of electronic devices such as word processors, computers, televisions, and other various display devices. However, these transparent materials have the problem that the dust and dirt are attached due to static electricity, and the transparency is easily impaired due to the occurrence of scratches and scratches due to the removal of the dirt.
Therefore, a transparent antistatic layer is formed on a transparent material.

  However, when an antistatic layer is formed on a transparent substrate, the reflected light on the surface of the transparent substrate interferes with the reflected light on the surface of the antistatic layer, resulting in unevenness called interference fringes due to film thickness unevenness. There was a problem that it was visually recognized as a pattern and the appearance was impaired.

  In order to solve this problem, there is a method of extremely increasing the thickness of the antistatic layer to several μm or more, or reducing it to about 100 nm. However, the former is caused by cracks or cost. The latter is not practical, and the latter has a problem that sufficient antistatic properties cannot be achieved, and is not practical.

  If the antistatic layer can be formed with a completely uniform film thickness, interference fringes should not occur. However, when manufacturing various products on an industrial scale, they are charged uniformly to such an extent that such interference fringes do not occur. It can be said that it is virtually impossible to form the prevention layer.

  The present invention intends to suppress the occurrence of interference fringes by controlling the difference in refractive index between two transparent layers (that is, a transparent base layer and an antistatic layer).

  Therefore, the optical film according to the present invention includes a transparent base layer and an antistatic layer formed on the transparent base layer, and the refractive index difference between the transparent base layer and the antistatic layer is set to be 0.1. Generation of interference fringes is suppressed by controlling to 03 or less, preferably 0.01 or less.

  In such an optical film according to the present invention, preferably, the antistatic layer may have a refractive index of 1.63 to 1.69.

  In such an optical film according to the present invention, preferably, the antistatic layer may be one in which conductive fine particles are dispersed in a transparent material.

In such an optical film according to the present invention, preferably, the conductive fine particles are made of SnO ₂ , ZnO, CeO ₂ , Sb ₂ O ₂ , In ₂ O ₃ , ITO, ATO, AZO and Al ₂ O _3. Can be selected from

  In the optical film according to the present invention, it is preferable that a low refractive index layer be provided on the surface of the antistatic layer.

  An optical display device with reduced interference fringes according to the present invention comprises the above optical film.

  An optical film according to the present invention comprises a transparent substrate layer and an antistatic layer formed on the transparent substrate layer, and the refractive index difference between the transparent substrate layer and the antistatic layer is 0.03 or less. Since it is preferably controlled to 0.01 or less, the occurrence of interference fringes is suppressed.

The present invention will be described below with reference to the drawings as necessary.
<Optical film>
1 to 3 schematically show cross sections of preferred specific examples of the optical film according to the present invention.
The optical film (1) according to the present invention shown in FIG. 1 comprises a transparent substrate layer (2) and an antistatic layer (3) formed on the transparent substrate layer (2), and the transparent group The occurrence of interference fringes is suppressed by controlling the refractive index difference between the material layer and the antistatic layer to 0.03 or less, and preferably 0.01 or less.

  FIG. 1 shows an optical film (1) composed of two transparent layers of a transparent substrate layer (2) and an antistatic layer (3). The optical film according to the present invention has three or more layers. A transparent layer may be formed.

  As a preferred specific example of the optical film (1) according to the present invention in which three or more transparent layers are formed, for example, as shown in FIG. 2, another transparent layer is formed on the surface of the antistatic layer (3). A layer (preferably, for example, a low refractive index layer (4)) was formed, and as shown in FIG. 3, another transparent layer (5) was formed on the surface of the transparent substrate layer (2). The thing etc. can be illustrated.

  In the optical film (1) according to the present invention shown in FIGS. 1 to 3, the difference in refractive index between the transparent base material layer (2) and the antistatic layer (3) is 0.03 or less, preferably 0.8. It is controlled to be 01 or less, and this mainly suppresses the generation of interference fringes in the optical film (1). That is, a part of the light (A) which has reached the optical film (1) according to the present invention from the observer side is part of the surface of the optical film (the surface (33) of the antistatic layer (3) in FIG. 2 is reflected on the surface (44) of the low refractive index layer (4) (this reflected light is shown as (A1)), and part of the light transmitted through this antistatic layer (3) is a transparent substrate. The light is reflected by the surface (22) of the layer (2) (that is, the interface between the transparent base material layer (2) and the antistatic layer (3)). Here, since the refractive index difference between the transparent base material layer (2) and the antistatic layer (3) is controlled as described above, the reflected light on the surface (22) of the transparent base material layer (2) Along with this, the intensity of the reflected light (A2) reflected in the equilibrium direction with the reflected light (A1) is also significantly lower than the intensity of the reflected light (A1). Thus, since the intensity | strength of reflected light (A2) is low, interference with reflected light (A1) and reflected light (A2) becomes weak, and generation | occurrence | production of an interference fringe is suppressed. Either the transparent substrate layer (2) or the antistatic layer (3) may have a large refractive index.

  In the case of the conventional optical film (10) as shown in FIG. 4, since the reflected light (A11) is strong and the interference with the reflected light (A1) is strong, the observed interference fringes are also strong.

<Transparent substrate layer>
In the optical film (1) according to the present invention, the transparent substrate layer (2) preferably has transparency and smoothness and does not contain foreign matter, and has mechanical strength for processing and use reasons. There are preferred. Furthermore, when the heat of the display is transmitted, one having heat resistance is preferable. However, this transparent substrate layer (2) is selected so that the refractive index difference with the antistatic layer (3) is controlled to 0.03 or less, preferably 0.01 or less, as described above. There is a need to. The transparent substrate layer (2) preferably has a refractive index of 1.50 to 1.70.

  Preferred materials for the transparent substrate layer (2) are cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, polyester, polyamide, polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polychlorinated. It is a film of a thermoplastic resin such as vinyl, polyvinyl acetal, polyetherketone, polymethyl methacrylate, polycarbonate, or polyurethane. Of these, polyester (refractive index: 1.65) is particularly preferable.

  Polyester often used in the case of a photographic film coated with a photographic emulsion, and cellulose triacetate (TAC) often used in a photographic film because it is highly transparent and optically anisotropic is usually preferable. . Although these thermoplastic resin films are flexible and easy to use, there is no need to bend them during handling, and when a hard one is desired, plate-like ones such as the above-mentioned resin plates and glass plates can also be used. Can be used. As thickness of a transparent base material layer (2), about 8-1000 micrometers is preferable, but in the case of a plate-shaped thing, you may exceed this range. As a special example of the transparent substrate layer (2), there may be a polarizing film in which both sides of a polarizer are sandwiched with a transparent plastic film.

  The transparent substrate layer (2) is usually used for improving the adhesion with other layers (preferably, for example, the low refractive index layer (4)) provided as necessary. In addition to various treatments that can be performed, that is, physical treatment such as corona discharge treatment and oxidation treatment, a primer layer can also be formed by previously applying a coating material called an anchor agent or primer.

<Antistatic layer>
In the optical film (1) according to the present invention, as a preferable specific example of the antistatic layer (3), one obtained by dispersing conductive ultrafine particles in a transparent resin can be exemplified. However, the antistatic layer (3) has a refractive index difference from the transparent base layer (2) controlled to 0.03 or less, preferably 0.01 or less, as described above. Need to choose.

Here, typical examples of the superconductive ultrafine particles include those made of a metal oxide. Examples of such metal oxides include ZnO (refractive index 1.90, the numerical value in parentheses below represents the refractive index), CeO ₂ (1.95), Sb ₂ O ₂ (1.71), SnO. ₂ (1.997), indium tin oxide (1.95) often referred to as ITO, In ₂ O ₃ (2.00), Al ₂ O ₃ (1.63), antimony-doped tin oxide (abbreviation) ATO, 2.0), aluminum-doped zinc oxide (abbreviation: AZO, 2.0), and the like.

  The ultrafine particles refer to those having a so-called submicron size of 1 micron or less, and preferably those having an average particle size of 0.1 nm to 0.1 μm.

In the present invention, when the transparent conductive ultrafine particles of the metal oxide as described above are dispersed, there is an advantage that the refractive index can be improved. When the conductivity is improved, the antistatic property is improved, but the surface resistance is preferably about 10 ⁸ to 10 ⁹ Ω / cm ² . In addition, when the refractive index is improved, the antireflective property is increased by the combination with other layers constituting the antireflective layer, that is, the combination with the low refractive index layer, for example, but the average for visible light (450 nm to 650 nm) The reflectance is preferably 2.5% or less.

  As the transparent resin constituting the antistatic layer (3), it is possible to use a thermoplastic resin, a thermosetting resin, an ionizing radiation curable resin, or an ionizing radiation curable compound (including an organic reactive silicon compound). it can. As the transparent resin, a thermoplastic resin can be used, but it is more preferable to use a thermosetting resin, and more preferable is an ionizing radiation curable resin containing an ionizing radiation curable resin or an ionizing radiation curable compound. It is a composition.

  The ionizing radiation curable composition is a mixture of a polymerizable unsaturated bond or a prepolymer, an oligomer, and / or a monomer having an epoxy group in a molecule. Here, the ionizing radiation refers to an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or crosslinking molecules, and usually an ultraviolet ray or an electron beam is used.

  Examples of prepolymers and oligomers in ionizing radiation curable compositions include unsaturated polyesters such as unsaturated dicarboxylic acid and polyhydric alcohol condensates, polyester methacrylates, polyether methacrylates, polyol methacrylates, methacrylates such as melamine methacrylates Acrylates such as polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polyol acrylate, and melamine acrylate, and cationic polymerization type epoxy compounds.

  Examples of the monomer in the ionizing radiation curable composition include styrene monomers such as styrene and α-methylstyrene, methyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, and butyl acrylate. Acrylic esters such as methoxybutyl acrylate and phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, ethoxymethyl methacrylate, phenyl methacrylate and lauryl methacrylate , 2- (N, N-diethylamino) ethyl acrylate, 2- (N, N-dimethylamino) ethyl acrylate, 2- (N, N-dibenzylamino) methyl acrylate, acrylic acid- 2- (N, N-diethyla B) Unsaturated substituted amino alcohol esters such as propyl, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol di Compounds such as acrylate, triethylene glycol diacrylate, polyfunctional compounds such as dipropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate, and / or two or more thiol groups in the molecule Polythiol compounds having, for example, trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, pentaerythritol tet And lathioglycolate.

  Usually, as the monomer in the ionizing radiation curable composition, the above compounds are used alone or in combination of two or more as required, but in order to give ordinary application suitability to the ionizing radiation curable composition. Further, the prepolymer or oligomer is preferably 5% by weight or more, and the monomer and / or polythiol compound is preferably 95% by weight or less.

  When flexibility is required when an ionizing radiation curable composition is applied and cured, it is preferable to reduce the amount of monomer or use an acrylate monomer having 1 or 2 functional groups. When wear resistance, heat resistance, and solvent resistance are required when an ionizing radiation curable composition is applied and cured, ionizing radiation curing such as using an acrylate monomer with three or more functional groups It is possible to design a sex composition. Here, 2-hydroxy acrylate, 2-hexyl acrylate, and phenoxyethyl acrylate are exemplified as those having one functional group. Examples of those having 2 functional groups include ethylene glycol diacrylate and 1,6-hexanediol diacrylate. Examples of the functional group having 3 or more include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

  In order to adjust physical properties such as flexibility and surface hardness when an ionizing radiation curable composition is applied and cured, a resin that is not cured by ionizing radiation irradiation can be added to the ionizing radiation curable composition. . Specific examples of the resin include the following. Thermoplastic resins such as polyurethane resin, cellulose resin, polyvinyl butyral resin, polyester resin, acrylic resin, polyvinyl chloride resin, and polyvinyl acetate. Among these, addition of a polyurethane resin, a cellulose resin, a polyvinyl butyral resin, or the like is preferable from the viewpoint of improving flexibility.

  When hardening after application | coating of an ionizing radiation curable composition is performed by ultraviolet irradiation, a photoinitiator and a photoinitiator are added. As the photopolymerization initiator, in the case of a resin system having a radical polymerizable unsaturated group, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether and the like are used alone or in combination. In the case of a resin system having a cationic polymerizable functional group, an aromatic diazonium salt, an aromatic sulfonium salt, an aromatic iodonium salt, a metatheron compound, a benzoin sulfonic acid ester or the like is used as a photopolymerization initiator alone or as a mixture . The addition amount of a photoinitiator is 0.1-10 weight part with respect to 100 weight part of ionizing radiation-curable compositions.

  In the ionizing radiation curable composition, the following organic reactive silicon compound may be used in combination.

1 of the organosilicon compound can be represented by the general formula R _m Si (OR ′) _n , R and R ′ represent an alkyl group having 1 to 10 carbon atoms, a subscript m of R and a subscript n of OR ′ Each is an integer satisfying the relationship m + n = 4.

  Specifically, tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, tetrapenta Ethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltri Butoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxysilane, methyl Silane, methyl diethoxy silane, hexyl trimethoxy silane and the like.

2 of the organosilicon compound that can be used in combination with the ionizing radiation curable composition is a silane coupling agent.
Specifically, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- Aminopropyltriethoxysilane, γ-methacryloxypropylmethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethoxysilane / hydrochloride, γ-glycidoxypropyltrimethoxysilane, aminosilane, methyl Methoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, vinyltris (β-methoxyethoxy) silane, octadecyldimethyl [3- (trimethoxysilyl) propyl ] Ammonium chloride, methyltrichlorosilane, dimethyldichlorosilane and the like.

上記（ａ）〜（ｅ）の式中、Ｒ^１およびＲ^２は炭素数１〜４のアルキル基であり、ａ〜ｄおよびｎは、分子量が５，０００以下になる値である。 The organosilicon compound that can be used in combination with the ionizing radiation curable composition is an ionizing radiation curable silicon compound.
Specific examples include a plurality of functional groups that react and crosslink by irradiation with ionizing radiation, for example, an organosilicon compound having a polymerizable double bond group and a molecular weight of 5,000 or less. Examples thereof include vinyl functional polysilane, vinyl functional polysilane at both ends, vinyl functional polysiloxane at one end, vinyl functional polysiloxane at both ends, vinyl functional polysilane obtained by reacting these compounds, or vinyl functional polysiloxane.
More specifically, it is the following compound.

In the above formulas (a) to (e), R ¹ and R ² are alkyl groups having 1 to 4 carbon atoms, and a to d and n are values with a molecular weight of 5,000 or less.

  Other organosilicon compounds that can be used in combination with ionizing radiation curable compositions include (meth) acryloxysilane compounds such as 3- (meth) acryloxypropyltrimethoxysilane and 3- (meth) acryloxypropylmethyldimethoxysilane. Etc.

  The antistatic layer (3) is made of a transparent resin, preferably an ionizing radiation curable composition as described above, and a transparent conductive ultrafine particle of a metal oxide and a transparent conductive ultrafine conductive resin / metal oxide. Fine particles = blended at a ratio (mass ratio) of 100/100 to 100/900, and if necessary, a photopolymerization initiator and a solvent or diluent are blended to prepare a coating composition, and this composition The product can be obtained by a known coating method, for example, by applying the product onto an object to be coated such as a transparent substrate and curing the coating film by means according to the composition used for the coating. When an ionizing radiation curable composition is used as the composition, ultraviolet rays or electron beams are selected and irradiated depending on the composition to crosslink and cure the coating film. The thickness of the antistatic layer (3) thus obtained is preferably about 30 nm to 1 μm.

  Such an antistatic layer (3) is preferably formed of a hard material in order to prevent the optical film (1) according to the present invention from being damaged and to improve durability. As such an appropriate hard material, those conventionally used as so-called hard coat layer forming materials in optical films can be used in the present invention.

  Generally, the hard coat layer is effective for improving the scratch resistance so that the surface of the optical film (1) is not damaged. The scratch is due to the difference in hardness from the substance causing the scratch, and in some cases, it may be composed of a composition containing a thermoplastic resin as a resin component, but in general it is thermosetting. It is preferable to use a composition obtained by curing a composition containing a functional resin as a resin component, and it is preferable to use a composition containing a polyurethane resin or the like as a resin component because it is flexible.

When a further effect is desired, the ionizing radiation curable resin or the ionizing radiation curable composition containing the ionizing radiation curable compound is preferably formed by crosslinking and curing by irradiation with ionizing radiation.
By such a thing, it is preferable to form the antistatic layer (3) which shows the hardness more than "H" by the pencil hardness test shown by JISK5400.

<Other transparent layers>
In the optical film (1) according to the invention shown in FIG. 2, a low refractive index layer (4) can be exemplified as a particularly preferred specific example of the other transparent layer. Such a low refractive index layer (4) is made of a transparent resin containing silica or magnesium fluoride, a fluorine resin which is a low refractive index resin, silica or a fluorine resin containing magnesium fluoride. Further, it can be constituted by a thin film having a refractive index of 1.46 or less, which is also about 30 nm to 1 μm, or a thin film by chemical vapor deposition or physical vapor deposition of silica or magnesium fluoride. About transparent resin other than a fluororesin, it is the same as that of the transparent resin used for comprising an antistatic layer (2).

  More preferably, the low refractive index layer (4) can be composed of a silicone-containing vinylidene fluoride copolymer. Specifically, this silicone-containing vinylidene fluoride copolymer is a monomer containing 30 to 90% vinylidene fluoride and 5 to 50% hexafluoropropylene (including percentages below, all in terms of mass). It is obtained by copolymerization using the composition as a raw material, and comprises 100 parts of a fluorine-containing copolymer having a fluorine content of 60 to 70% and 80 to 150 parts of a polymerizable compound having an ethylenically unsaturated group. A low refractive index having a refractive index of less than 1.60 (preferably 1.46 or less) which is a thin film having a film thickness of 200 nm or less and is provided with scratch resistance by using this resin composition. Layer (4) is formed.

  The silicone-containing vinylidene fluoride copolymer constituting the low refractive index layer (4) is such that the proportion of each component in the monomer composition is 30 to 90%, preferably 40 to 80%, particularly preferably vinylidene fluoride. Is 40 to 70%, and hexafluoropropylene is 5 to 50%, preferably 10 to 50%, particularly preferably 15 to 45%. This monomer composition may further contain 0 to 40%, preferably 0 to 35%, particularly preferably 10 to 30% of tetrafluoroethylene.

  In the above monomer composition, other copolymer components are, for example, in the range of 20% or less, preferably in the range of 10% or less, within the range in which the intended purpose and effect of the silicone-containing vinylidene fluoride copolymer are not impaired. Specific examples of such other copolymerization components are fluoroethylene, trifluoroethylene, chlorotrifluoroethylene, 1,2-dichloro-1,2-difluoroethylene, 2-bromo-3,3,3-trifluoroethylene, 3-bromo-3,3-difluoropropylene, 3,3,3-trifluoropropylene, 1,1,2-trichloro-3,3,3-tri Examples thereof include polymerizable monomers having fluorine atoms such as fluoropropylene and α-trifluoromethacrylic acid.

  The fluorine-containing copolymer obtained from the monomer composition as described above needs to have a fluorine content of 60 to 70%, preferably a fluorine content of 62 to 70%, particularly preferably 64 to 68. %. When the fluorine content is in such a specific range, the fluorine-containing polymer has good solubility in a solvent, and contains such a fluorine-containing polymer as a component. Since it has excellent adhesion to various substrates, it forms a thin film with high transparency and low refractive index and sufficiently excellent mechanical strength, so the scratch resistance of the surface on which the thin film is formed The mechanical properties such as the above can be made sufficiently high, which is extremely suitable.

  The fluorine-containing copolymer preferably has a molecular weight of 5,000 to 200,000, particularly 10,000 to 100,000 in terms of polystyrene-equivalent number average molecular weight. By using a fluorine-containing copolymer having such a molecular weight, the viscosity of the resulting fluorine-based resin composition becomes a suitable size, and therefore surely has a suitable coating property. It can be. The fluorine-containing copolymer preferably has a refractive index of 1.45 or less, particularly 1.42 or less, more preferably 1.40 or less. When a fluorine-containing copolymer having a refractive index exceeding 1.45 is used, a thin film formed from the obtained fluorine-based paint may have a small antireflection effect.

In addition, the low refractive index layer (4) may also be a thin film made of SiO _2, an evaporation method, a sputtering method, or a plasma CVD method or the like, or SiO ₂ gel film from the sol solution containing SiO ₂ sol It may be formed by a method of forming. The low refractive index layer (4), in addition to SiO ₂ also, the or a thin film MgF _2, but may be configured in other materials, in terms of high adhesion to the lower layer, it is preferable to use a SiO ₂ thin film . Among the above methods, when the plasma CVD method is used, it is preferable to use organosiloxane as a raw material gas under the condition that there is no other inorganic vapor deposition source, and to maintain the deposition target as low as possible. It is preferable.

  The following examples illustrate some particularly preferred embodiments of the optical film according to the present invention.

<Example 1>
ES-3 (hard coating agent in which tin oxide fine particles are dispersed (solid content 30) on one surface of polyester film A-4300 (base film Toyobo Co., Ltd., product name, refractive index 1.65) having a thickness of 188 μm %) Dainippon Paint Co., Ltd. trade name, refractive index 1.69) and pentaerythritol triacrylate (PETA) mixed in a ratio of 25: 2, coated with a bar coater and dried with a solvent. Then, it was cured by irradiating with ultraviolet rays to form an antistatic layer (refractive index: 1.65) having a thickness of 2 μm. Next, a paint in which three components of colloidal silica, dipentaerythritol triacrylate (DPHA), and a reactive polyvinylidene fluoride derivative (manufactured by Daikin Industries, Ltd .: OPTOOL AR110 (trade name)) are blended on the hard coat layer. Was diluted with MIBK, coated with a bar coater, dried, and then cured by irradiation with ultraviolet rays under a nitrogen purge to form a low refractive index layer (refractive index of 1.43) having a thickness of 100 nm. A low reflection antistatic hard coat film was prepared.

<Example 2>
ES-3 (hard coating agent in which tin oxide fine particles are dispersed (solid content 30) on one surface of polyester film A-4300 (base film Toyobo Co., Ltd., product name, refractive index 1.65) having a thickness of 188 μm %) Dainippon Paint Co., Ltd. product name, refractive index 1.69) was applied, dried, and then cured by irradiating with ultraviolet rays to form an antistatic layer (refractive index 1.69) having a thickness of 2 μm. . Next, a paint in which three components of colloidal silica, dipentaerythritol triacrylate (DPHA), and a reactive polyvinylidene fluoride derivative (manufactured by Daikin Industries, Ltd .: OPTOOL AR110 (trade name)) are blended on the hard coat layer. Was diluted with MIBK, coated with a bar coater, dried, and then cured by irradiation with ultraviolet rays under a nitrogen purge to form a low refractive index layer (refractive index 1.43) having a thickness of 100 nm. A low reflection antistatic hard coat film was prepared.

<Example 3>
ES-3 (hard coating agent in which tin oxide fine particles are dispersed (solid content 30) on one surface of polyester film A-4300 (base film Toyobo Co., Ltd., product name, refractive index 1.65) having a thickness of 188 μm %) Dainippon Paint Co., Ltd. trade name, refractive index 1.69) and pentaerythritol triacrylate (PETA) mixed in a ratio of 20: 3, and the paint diluted with solvent is applied with a bar coater and dried. The film was cured by irradiating with ultraviolet rays to form an antistatic layer (refractive index of 1.63) having a thickness of 2 μm. Next, a paint in which three components of colloidal silica, dipentaerythritol triacrylate (DPHA), and a reactive polyvinylidene fluoride derivative (manufactured by Daikin Industries, Ltd .: OPTOOL AR110 (trade name)) are blended on the hard coat layer. (Refractive index 1.43) diluted with MIBK, coated with a bar coater, dried, then cured by irradiation with ultraviolet rays under a nitrogen purge to form a low refractive index layer (refractive index 1.43) having a thickness of 100 nm. The low reflection antistatic hard coat film of Example 3 was produced.

<Comparative Example 1>
ES-3 (hard coating agent in which tin oxide fine particles are dispersed (solid content 30) on one surface of polyester film A-4300 (base film Toyobo Co., Ltd., product name, refractive index 1.65) having a thickness of 188 μm %) Dainippon Paint Co., Ltd. trade name, refractive index 1.69) and pentaerythritol triacrylate (PETA) are mixed at a ratio of 3 to 1, and the paint diluted with solvent is applied with a bar coater and dried. Then, it was cured by irradiating with ultraviolet rays to form an antistatic layer (refractive index of 1.60) having a thickness of 2 μm. Next, a paint in which three components of colloidal silica, dipentaerythritol triacrylate (DPHA), and a reactive polyvinylidene fluoride derivative (manufactured by Daikin Industries, Ltd .: OPTOOL AR110 (trade name)) are blended on the hard coat layer. (Refractive index 1.43) diluted with MIBK, coated with a bar coater, dried, then cured by irradiation with ultraviolet rays under a nitrogen purge to form a low refractive index layer (refractive index 1.43) having a thickness of 100 nm. Then, a low reflection antistatic hard coat film of Comparative Example 1 was produced.

<Comparative example 2>
KZ7111 (hard coating agent in which zirconia fine particles are dispersed (solid content 50%) JSR) on one surface of polyester film A-4300 (base film Toyobo Co., Ltd., product name, refractive index 1.65) having a thickness of 188 μm The product name, refractive index 1.72 manufactured by Co., Ltd. is diluted with a solvent, coated with a bar coater, dried, then cured by irradiation with ultraviolet rays, and an antistatic layer having a thickness of 2 μm (refractive index 1.72). Formed. Next, a paint in which three components of colloidal silica, dipentaerythritol triacrylate (DPHA), and a reactive polyvinylidene fluoride derivative (manufactured by Daikin Industries, Ltd .: OPTOOL AR110 (trade name)) are blended on the hard coat layer. (Refractive index 1.43) diluted with MIBK, coated with a bar coater, dried, then cured by irradiation with ultraviolet rays under a nitrogen purge to form a low refractive index layer (refractive index 1.43) having a thickness of 100 nm. Then, a low reflection antistatic hard coat film of Comparative Example 2 was produced.

測定方法
１．干渉縞：目視判定 ◎ほとんど無い、○目立たない、×目立つ
２．ヘイズ、全光線透過率：（ＪＩＳ−Ｋ６７１４）村上色彩技術研究所製反射透過率計ＨＭ−１５０使用
３．視感反応率：島津製作所製 分光反射率測定機ＰＣ−３１００を使用し、フィルムの裏面を黒処理し、５℃正反射の反射率を測定
４．表面鉛筆硬度：（ＪＩＳ−Ｋ５４００） タクマ精工製 簡易鉛筆引っかき試験機を用いて、ＭＩＴＳＵＢＩＳＨＩ ＵＮＩ（Ｈ〜３Ｈ）で１ｋｇ荷重の５回ストロークを行い、目視で傷の有無を確認し、傷のつかない回数が４回以上なら合格とする。 <Comparative Example 3>
PETA is diluted with a solvent on one side of a 188 μm thick polyester film A-4300 (base film Toyobo Co., Ltd., product name, refractive index 1.65), coated with a bar coater, dried, and then exposed to ultraviolet light. Was cured by irradiation to form a hard coat layer having a thickness of 5 μm. On the above hard coat layer, ES-3 (hard coat agent in which tin oxide fine particles are dispersed (solid content: 30%), Dainippon Paint Co., Ltd., trade name, refractive index: 1.69) is diluted with a solvent, and bar coater After coating and drying, the film was cured by irradiation with ultraviolet light under nitrogen to form an antistatic layer (refractive index 1.69) having a thickness of 80 nm. Subsequently, a coating material containing three components of colloidal silica, dipentaerythritol triacrylate (DPHA) and reactive polyvinylidene fluoride derivative (manufactured by Daikin Industries, Ltd .: OPTOOL AR110 (trade name)) on the conductive layer ( Refractive index 1.43) is diluted with MIBK, coated with a bar coater, dried, and then cured by irradiation with ultraviolet rays under a nitrogen purge to form a low refractive index layer (refractive index 1.43) having a thickness of 100 nm. Then, a low reflection antistatic hard coat film of Comparative Example 3 was produced.

Measuring method 1. Interference fringes: Visual judgment ◎ Almost no, ○ Inconspicuous, × Conspicuous 2. Haze, total light transmittance: (JIS-K6714) Murakami Color Research Laboratory reflective transmittance meter HM-150 used 3. Luminous reaction rate: Using a spectral reflectance measuring machine PC-3100 manufactured by Shimadzu Corporation, the back side of the film was black-treated, and the reflectance of 5 ° C. regular reflection was measured. Surface pencil hardness: (JIS-K5400) Using a simple pencil scratch tester manufactured by Takuma Seiko, perform 5 strokes of 1kg load with MITSUBISHI UNI (H-3H), visually check for scratches and scratches. If there are no more than 4 times, then pass.

5). Surface resistivity: measured using a resistivity meter MCP-HT260 manufactured by Mitsubishi Chemical

The schematic diagram which shows the cross section of the preferable example of the optical film by this invention The schematic diagram which shows the cross section of the preferable example of the optical film by this invention The schematic diagram which shows the cross section of the preferable example of the optical film by this invention Schematic showing the cross section of a conventional optical film

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical film 2 Transparent base material layer 3 Antistatic layer 4 Low refractive index layer 5 Other transparent layers

Claims (6)

A transparent substrate layer;
It consists of an antistatic layer formed on this transparent substrate layer,
The occurrence of interference fringes is suppressed by controlling the difference in refractive index between the transparent substrate layer and the antistatic layer to 0.03 or less, preferably 0.01 or less. the film.   The optical film according to claim 1, wherein the antistatic layer has a refractive index of 1.63 to 1.69.   The optical film according to claim 1, wherein the antistatic layer is one in which conductive fine particles are dispersed in a transparent material. The conductive fine particles _are those selected from the group consisting of _{SnO 2, ZnO, CeO 2,} Sb 2 O 2, In 2 O 3, ITO, ATO, AZO , and _Al 2 _{O 3,} according to claim 3 Optical film.   The optical film of any one of Claims 1-4 which has a low-refractive-index layer on the surface of the said antistatic layer.   An optical display device with reduced interference fringes, comprising the optical film according to claim 1.

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