JP2004034399A - Hard coat film, its manufacturing method, optical element, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard coat film which has abrasion resistance and electric conduction characteristics and is free from defective adhesion. <P>SOLUTION: In the hard coat film having a hard coat layer formed from a transparent resin on a transparent substrate film, fine conductive particles are dispersed in the hard coat layer to form a concentration distribution in the thickness direction, and the concentration of the particles on the substrate film side is increased. <P>COPYRIGHT: (C)2004,JPO

Description

表１から、本発明の反射防止ハードコートフィルム（実施例）は、透明導電層、ハードコート層を個別に作成した場合（比較例１）と同様の反射率、導電性を有し、かつ密着性も良好であることが認められる。比較例２では、導電性微粒子の密度が小さく導電性を発現しにくい。
【図面の簡単な説明】
【図１】本発明のハードコートフィルムの一例である。
【図２】本発明の反射防止ハードコートフィルムの一例である。
【符号の説明】
１　　透明基材フィルム
２　　ハードコート層
３　　導電性微粒子
４　　反射防止層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hard coat film and a method for producing the same. The optical element such as a polarizing plate using the hard coat film of the present invention can be suitably used in various image display devices such as a liquid crystal display (LCD), an organic EL display device, and an FPD (flat panel display) such as a PDP.
[0002]
[Prior art]
In a liquid crystal display, it is indispensable to arrange polarizers on both sides of a glass substrate forming a liquid crystal panel due to its image forming method. Generally, a polarizing plate having a transparent protective film provided on one or both sides of a polarizer is used. The transparent protective film for a polarizing plate used on the viewing side is very easily scratched. Therefore, the transparent protective film is used as a hard coat film having a hard coat layer formed of a transparent resin layer such as an acrylic resin or a urethane acrylate resin for the purpose of improving scratch resistance.
[0003]
In addition, static electricity is easily generated on the surface of a display such as a liquid crystal display, and dust such as dust easily adheres to the surface of the display due to the static electricity. Further, the function of the display may be hindered by static electricity. Therefore, a transparent conductive layer is provided between the transparent protective film and the hard coat layer for the purpose of imparting antistatic properties to the hard coat film used for the polarizing plate or the like, thereby preventing adverse effects due to static electricity. The transparent conductive layer is formed of a transparent conductive layer forming material in which conductive fine particles are dispersed and contained in a transparent resin.
[0004]
However, if the transparent conductive layer contains a sufficient amount of conductive fine particles sufficient to eliminate the adverse effects of static electricity, the adhesion to the hard coat layer formed on the transparent conductive layer becomes insufficient. In order to improve the adhesion, a method of forming a hard coat layer while keeping the transparent conductive layer half-cured is also considered. However, such a method has a risk that the transparent conductive layer may be scratched or the like, which is difficult to employ.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a hard coat film having scratch resistance and conductive properties and having no poor adhesion. Another object of the present invention is to provide an optical element such as a polarizing plate using the hard coat film, and an image display device equipped with the optical element or the like.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that the above object can be achieved by the following antireflection hard coat film, and have completed the present invention.
[0007]
That is, the present invention, in a hard coat film having a hard coat layer formed of a transparent resin on a transparent base film, the conductive fine particles are unevenly distributed in the hard coat layer with a concentration distribution in a thickness direction. And a hard coat film characterized in that the concentration of conductive fine particles on the transparent substrate film side is high.
[0008]
In the present invention, the conductive fine particles are unevenly distributed on the transparent substrate film side in the hard coat layer, and the transparent substrate film side in the hard coat layer is an apparent transparent conductive layer (hereinafter, referred to as an apparent transparent conductive layer). ) Is formed. As a result, in the hard coat layer on the transparent substrate film side, the apparent transparent conductive layer secures the conductive properties, and on the opposite hard coat layer, the scratch resistance is secured. In addition, since the conductive property and the scratch resistance can be formed at once by a single hard coat layer, there is no problem of poor adhesion. In addition, when the conductive fine particles are uniformly distributed in the hard coat layer, the density of the conductive fine particles becomes small, so that it becomes difficult to exhibit conductivity.
[0009]
The degree of uneven distribution of the conductive fine particles in the hard coat layer can be determined by cross-sectional observation using a TEM or the like. The degree of uneven distribution is, for example, as shown in FIG. 1, the ratio (L ₂ / L) of the thickness (L ₂ ) of the hard coat layer 2 from the transparent base film 1 side to the thickness (L ₁ ) of the hard coat layer 2. The case where the range of the thickness (L ₂ ) at which L ₁ ) is 0.7 or less includes 50% or more, and more preferably 70% or more, of the conductive fine particles 3 in the hard coat layer 2. The ratio (L ₂ / L ₁ ) is more preferably 0.5 or less.
[0010]
In the hard coat film, the specific gravity (d ₁ ) of the conductive fine particles is preferably larger than the specific gravity (d ₂ ) of the transparent resin. When the specific gravity of the conductive fine particles (d ₁ )> the specific gravity of the transparent resin (d ₂ ), the conductive fine particles are easily unevenly distributed on the transparent substrate film side by utilizing the specific gravity difference. The specific gravity difference (d ₁ -d ₂ ) is preferably 0.1 or more, more preferably 0.3 or more, in order to unevenly distribute the conductive fine particles on the transparent substrate film side.
[0011]
In the hard coat film, it is preferable that the hard coat layer is formed of two or more transparent resins. In the formation of the hard coat layer, the apparent transparent conductive layer can be formed more easily by using two or more transparent resins having different specific gravities.
[0012]
The present invention also relates to a hard coat film, wherein an anti-reflection layer is formed on the hard coat layer of the hard coat film. The hard coat film of the present invention can be used as an anti-reflection hard coat film having a low reflectance by forming an anti-reflection layer.
[0013]
Further, the present invention, on a transparent substrate film, a transparent resin solution containing conductive fine particles is applied, and after the fine particles settle on the transparent substrate film side, the transparent resin is cured to form a hard coat layer. And a method for producing the hard coat film. According to this manufacturing method, a hard coat film in which the conductive fine particles in the hard coat layer are unevenly distributed on the transparent substrate film side can be manufactured.
[0014]
The present invention also relates to an optical element, wherein the hard coat film is provided on one or both sides of the optical element. Furthermore, the present invention relates to an image display device equipped with the hard coat film or the optical element. An optical element such as a polarizing plate using the hard coat film of the present invention has excellent scratch resistance and conductive properties, and has no problem of poor adhesion. Also, it has excellent optical characteristics. Further, the optical element can be used for various purposes, and an image display device such as a liquid crystal display device provided with the optical element has good display quality.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a hard coat film in which a hard coat layer 2 is laminated on one side of a transparent substrate film 1. In the hard coat layer 2, the conductive fine particles 3 are unevenly distributed on the side of the transparent substrate film 1, and an apparent transparent conductive layer is formed in the range of the thickness (L ₂ ). FIG. 2 shows an antireflection hard coat film in which an antireflection layer 4 is laminated on the hard coat layer 2.
[0016]
As the transparent substrate film 1, a film excellent in transparency, mechanical strength, heat stability, moisture shielding property, isotropy and the like is preferable. Examples thereof include films made of transparent polymers such as polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, polycarbonate polymers, and acrylic polymers such as polymethyl methacrylate. Styrene polymers such as polystyrene and acrylonitrile / styrene copolymer; polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure; olefin polymers such as ethylene / propylene copolymer; vinyl chloride polymers; nylon and aromatic polyamides And a film made of a transparent polymer such as an amide-based polymer. Furthermore, imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers Films made of transparent polymers such as polymers, epoxy polymers and blends of the above polymers are also included. In many cases, the transparent protective film preferably has a smaller optical anisotropy such as retardation.
[0017]
The thickness of the transparent substrate film 1 can be determined as appropriate, but is generally about 10 to 300 μm from the viewpoint of workability such as strength and handleability, and thin layer properties. In particular, 20 to 300 μm is preferable, and 30 to 200 μm is more preferable. The refractive index of the transparent substrate film 4 is about 1.43 to 1.6, preferably about 1.45 to 1.5.
[0018]
The transparent resin forming the hard coat layer 2 is not particularly limited as long as it has excellent hard coat properties (a hardness of H or higher in a pencil hardness test according to JIS K5400), sufficient strength, and excellent light transmittance. There is no. For example, a thermosetting resin, a thermoplastic resin, an ultraviolet curable resin, an electron beam curable resin, a two-component mixed resin, and the like can be given. Among these, a UV-curable resin that can efficiently form a light-diffusing layer by a simple processing operation in a curing treatment by UV irradiation is preferable. Examples of the UV-curable resin include various resins such as polyester, acrylic, urethane, amide, silicone, and epoxy resins, and include UV-curable monomers, oligomers, and polymers. The UV-curable resin preferably used is, for example, a resin having a UV-polymerizable functional group, among which those containing a component of an acrylic monomer or oligomer having two or more, particularly 3 to 6 functional groups are mentioned. . Further, an ultraviolet ray polymerization initiator is blended with the ultraviolet ray curable resin.
[0019]
In addition, examples of the transparent resin forming the hard coat layer 2 include a sol-gel material using a metal alkoxide such as an alkoxysilanealkoxytitanium. Of these, alkoxysilanes are preferred. These form a polysiloxane structure. Specific examples of the alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetraalkoxysilanes such as tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyl Tributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3- Glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylto Ethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, trialkoxysilanes such as 3,4-epoxycyclohexylethyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, Examples include diethyldimethoxysilane and diethyldiethoxysilane. These alkoxysilanes can be used as a partial condensate thereof. Among these, tetraalkoxysilanes or partial condensates thereof are preferred. Particularly, tetramethoxysilane, tetraethoxysilane or a partial condensate thereof is preferable.
[0020]
The transparent resin forming the hard coat layer 2, one or two or more, can be selected and used appropriately, as described above, the transparent resin density (d _2), the specific gravity of the conductive particles 3 (d ₁ ) Are preferred.
[0021]
When two or more transparent resins are used, a metal alkoxide such as an alkoxysilane is selected as a transparent resin for forming an apparent transparent conductive layer, and acrylic or acrylic is used as a transparent resin for forming other hard coat layers. It is preferable to select a UV-curable resin such as a urethane-based resin.
[0022]
Examples of the conductive fine particles 3 include metal fine particles such as aluminum, titanium, tin, gold, and silver, and ultrafine particles such as ITO (indium oxide / tin oxide) and ATO (antimony oxide / tin oxide). It is preferable that the average particle diameter of the conductive ultrafine particles is usually about 0.1 μm or less. The amount of the conductive fine particles 3 used is not particularly limited as long as the apparent transparent conductive layer can exhibit antistatic properties. Usually, it is preferable to add 5 to 95 parts by weight, more preferably 10 to 90 parts by weight, based on 100 parts by weight of the transparent resin (solid content).
[0023]
The method for forming the hard coat layer 2 is not particularly limited as long as the conductive fine particles 3 can be formed unevenly on the transparent substrate film 1 side. For example, a transparent resin solution containing the conductive fine particles 3 is applied to the transparent base film 1, the conductive fine particles 3 are settled on the transparent base film 1 side, and then the transparent resin is cured to form the hard coat layer 2. Can be adopted. When the conductive fine particles are unevenly distributed, the density of the conductive fine particles increases, and as a result, conductivity is exhibited and the surface resistance value decreases.
[0024]
The transparent resin solution is applied by an appropriate method such as a bar coater such as a wire bar, a microgravure coater, a die coater, casting, spin coating, and fountain metalling. Examples of the solvent for dissolving the transparent resin include common solvents such as toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, isopropyl alcohol, and ethyl alcohol. Confirmation of sedimentation of the conductive fine particles 3 can be performed by TEM observation. Usually, after the application of the transparent resin solution, the conductive fine particles 3 can be sedimented by being left for 0.5 minutes or more, preferably 1 minute or more.
[0025]
The thickness of the hard coat layer 2 is not particularly limited, but is preferably about 1 to 10 μm, particularly preferably 3 to 5 μm.
[0026]
The refractive index of the hard coat layer 2 is preferably adjusted to be higher than the refractive index of the transparent substrate film 1 from the viewpoint of optical characteristics.
[0027]
The hard coat layer 2 can be adjusted to a high refractive index by adding ultrafine particles of a metal or a metal oxide having a high refractive index. Examples of the ultrafine particles having a high refractive index include ultrafine particles of a metal oxide such as TiO ₂ , SnO ₂ , ZnO ₂ , ZrO ₂ , and aluminum oxide. The average particle diameter of such ultrafine particles is usually preferably about 0.1 μm or less. The ultrafine particles having a high refractive index can be almost uniformly dispersed in the hard coat layer 2.
[0028]
It is preferable to adjust the refractive index of the hard coat layer 2 so that the apparent transparent conductive layer <the other hard coat layer from the viewpoint of improving the antireflection function. The apparent transparent conductive layer has a refractive index of 1.55 to 1.65, more preferably 1.57 to 1.63, and the other hard coat layer has a refractive index of 1.55 to 1.85, and more preferably 1.65 to 1.65. .75 is preferred.
[0029]
The surface of the hard coat layer 2 can have a fine uneven structure to provide antiglare properties. By making the surface of the hard coat layer uneven, anti-glare properties due to light diffusion can be imparted. The provision of light diffusing properties is also preferable in reducing the reflectance.
[0030]
The method for forming the fine uneven structure on the surface is not particularly limited, and an appropriate method can be adopted. For example, the surface of the transparent substrate film 1 used for forming the hard coat layer 2 is roughened in advance by an appropriate method such as sand blasting, embossing roll, or chemical etching to provide a fine uneven structure on the film surface. For example, there is a method of forming the surface of the material itself forming the hard coat layer 2 into a fine uneven structure. Further, there is a method in which the hard coat layer 2 is separately applied on the hard coat layer 2 to give a fine uneven structure to the surface of the resin film layer by a transfer method using a mold or the like. In addition, there is a method in which an inorganic or organic spherical or amorphous filler is dispersed and contained in the hard coat layer 2 to give a fine uneven structure. These fine uneven structures may be formed by combining two or more types of methods and forming a layer in which the surfaces of the fine uneven structures in different states are combined.
[0031]
As a method for forming the hard coat layer 2 on the surface of the fine uneven structure, a method in which the hard coat layer 2 containing a dispersed inorganic or organic spherical or amorphous filler is preferable from the viewpoint of formability and the like. Examples of the inorganic or organic spherical or amorphous filler include, for example, crosslinked or uncrosslinked organic fine particles made of various polymers such as PMMA (polymethyl methacrylate), polyurethane, polystyrene, and melamine resin, glass, silica, alumina, and oxide. Examples include inorganic particles such as calcium, titania, zirconium oxide, and zinc oxide, and conductive inorganic particles such as tin oxide, indium oxide, cadmium oxide, antimony oxide, and a composite thereof. The average particle diameter of the filler is preferably 0.5 to 10 μm, more preferably 1 to 4 μm. In the case of forming a fine uneven structure with fine particles, the amount of fine particles used is preferably about 1 to 30 parts by weight based on 100 parts by weight of the resin.
[0032]
The hard coat layer (anti-glare layer) 2 may contain additives such as a leveling agent, a thixotropic agent, and an antistatic agent. In forming the hard coat layer (anti-glare layer) 2, by including a thixotropic agent (silica, mica, etc. of 0.1 μm or less), a fine uneven structure can be easily formed on the surface of the anti-glare layer by protruding particles. Can be.
[0033]
The method for forming the antireflection layer 4 is not particularly limited, but a wet coating method using a low refractive index material having a lower refractive index than the hard coat layer 2 is a simpler method than a vacuum deposition method or the like. Yes and preferred. Examples of a material for forming the antireflection layer 4 include a resin-based material such as an ultraviolet curable acrylic resin, a hybrid-based material in which inorganic fine particles such as colloidal silica are dispersed in a resin, tetraethoxysilane, titanium tetraethoxide, and the like. And sol-gel based materials using metal alkoxides of the above. In addition, a fluorine group-containing compound is used for each material in order to impart surface contamination resistance. From the viewpoint of scratch resistance, a low refractive index layer material having a large content of an inorganic component tends to be excellent, and a sol-gel material is particularly preferable. The sol-gel material can be used after being partially condensed.
[0034]
Examples of the sol-gel material containing a fluorine group include perfluoroalkylalkoxysilane. As the perfluoroalkylalkoxysilane, for example, the general formula (1): CF ₃ (CF ₂ ) _n CH ₂ CH ₂ Si (OR) ₃ (wherein, R represents an alkyl group having 1 to 5 carbon atoms) , N represents an integer of 0 to 12). Specifically, for example, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane Ethoxysilane and the like can be mentioned. Of these, compounds wherein n is 2 to 6 are preferred.
[0035]
The antireflection layer 4 may contain a sol in which silica, alumina, titania, zirconia, magnesium fluoride, ceria, or the like is dispersed in an alcohol solvent. In addition, additives such as metal salts and metal compounds can be appropriately compounded.
[0036]
The refractive index of the antireflection layer 4 is lower than the refractive index of the hard coat layer 2. Further, it is preferable to adjust the refractive index so as to be lower than the refractive index of the transparent substrate film 1. The refractive index of the antireflection layer 4 is preferably from 1.35 to 1.45, and more preferably from 1.37 to 1.43.
[0037]
The method for forming the antireflection layer 4 is not particularly limited, and is applied on the hard coat layer 2 by an appropriate method. For example, it can be formed by an appropriate method such as a doctor blade method, a gravure roll coater method, and a dipping method.
[0038]
The thickness of the antireflection layer 4 is not particularly limited, and is usually about 80 to 150 nm on average. The thickness of the antireflection layer 4 is determined so as to be near the target wavelength by the refractive index of the material to be used and the set wavelength of the incident light. Target wavelength = set wavelength {4} refractive index. For example, assuming that the refractive index of the antireflection layer 4 is 1.38 and the design wavelength of the incident light on the antireflection layer 4 is 550 nm, the target thickness of the antireflection layer 4 is about 550 nm ÷ 4 ÷ 1.38 = 100 nm. .
[0039]
An optical element can be bonded to the transparent base film 1 of the hard coat film. Examples of the optical element include a polarizer. The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, and a dichromatic dye such as iodine or a dichroic dye. And uniaxially stretched by adsorbing a hydrophilic substance, or a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among these, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.
[0040]
A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine, and stretching the film to 3 to 7 times its original length. If necessary, it can be immersed in an aqueous solution of boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, dirt on the surface of the polyvinyl alcohol-based film and an anti-blocking agent can be washed off. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.
[0041]
The polarizer is usually provided with a transparent protective film on one or both sides and used as a polarizing plate. The transparent protective film preferably has excellent transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like. As the transparent protective film, a material having the same material as that of the above-mentioned transparent base film is used. As the transparent protective film, a transparent protective film made of the same polymer material on both sides may be used, or a transparent protective film made of a different polymer material or the like may be used. Those excellent in transparency, mechanical strength, heat stability, moisture barrier property, etc. are preferably used. In many cases, the transparent protective film preferably has a smaller optical anisotropy such as a retardation. Triacetyl cellulose is most suitable as the polymer forming the transparent protective film. When the hard coat film is provided on one side or both sides of a polarizer (polarizing plate), the transparent base film of the hard coat film can also serve as a transparent protective film of the polarizer. Although the thickness of the transparent protective film is not particularly limited, it is generally about 10 to 300 μm.
[0042]
The antireflection polarizing plate in which the polarizing plate is laminated on the hard coat film may be a transparent protective film, a polarizer, and a transparent protective film sequentially laminated on the hard coat film, or the polarizer and the transparent protective film may be laminated on the hard coat film. The layers may be sequentially laminated.
[0043]
In addition, the surface of the transparent protective film on which the polarizer is not adhered may be subjected to a hard coat layer, a process for preventing sticking, or a process for the purpose. The hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate, for example, by applying a suitable ultraviolet-curable resin such as an acrylic resin or a silicone resin to a cured film having excellent hardness and sliding properties, etc., as a transparent protective film. It can be formed by a method of adding to the surface of. In addition, the anti-sticking treatment is performed for the purpose of preventing adhesion to an adjacent layer. The hard coat layer, the anti-sticking layer and the like can be provided on the transparent protective film itself, or can be separately provided as an optical layer separately from the transparent protective film.
[0044]
In addition, for example, a hard coat layer, a primer layer, an adhesive layer, an adhesive layer, an adhesive layer, an antistatic layer, a conductive layer, a gas barrier layer, a water vapor barrier layer, a moisture barrier layer, etc. are inserted between the layers of the polarizing plate, or to the surface of the polarizing plate. They may be stacked. Also. In the stage of forming each layer of the polarizing plate, for example, improvement may be made as necessary by adding, mixing, or the like, conductive particles, an antistatic agent, various fine particles, a plasticizer, and the like to a material forming each layer.
[0045]
In practical use, an optical film in which another optical element (optical layer) is laminated on the polarizing plate can be used as the optical element. The optical layer is not particularly limited. For example, the optical layer is used for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wavelength plate such as 1/2 or 1/4), and a viewing angle compensation film. One or more optical layers that may be used may be used. In particular, a reflective polarizing plate or a semi-transmitting polarizing plate in which a reflecting plate or a transflective reflecting plate is further laminated on a polarizing plate, an elliptically polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate, a polarized light A wide viewing angle polarizing plate obtained by further laminating a viewing angle compensation film on a plate, or a polarizing plate obtained by further laminating a brightness enhancement film on a polarizing plate is preferable. In an elliptically polarizing plate, a polarizing plate with optical compensation, etc., a hard coat film is provided on the polarizing plate side.
[0046]
Further, if necessary, various properties such as scratch resistance, durability, weather resistance, moist heat resistance, heat resistance, moisture resistance, moisture permeability, antistatic property, conductivity, improved adhesion between layers, improved mechanical strength, Processing for imparting a function or the like, or insertion and lamination of a functional layer can also be performed.
[0047]
The reflection type polarizing plate is provided with a reflection layer on a polarizing plate, and is used to form a liquid crystal display device of a type that reflects incident light from a viewing side (display side) and displays the reflected light. There is an advantage that the built-in light source can be omitted, and the liquid crystal display device can be easily made thinner. The reflection type 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 provided on one surface of the polarizing plate via the transparent protective film or the like, if necessary.
[0048]
Specific examples of the reflective polarizing plate include those in which a reflective layer formed by attaching a foil or a vapor-deposited film made of a reflective metal such as aluminum to one surface of a transparent protective film that has been matted as necessary.
[0049]
The reflection plate can be used as a reflection sheet or the like in which a reflection layer is provided on an appropriate film conforming to the transparent film, instead of directly applying the reflection plate to the transparent protective film of the polarizing plate. Since the reflective layer is usually made of a metal, the use form in which the reflective surface is covered with a transparent protective film, a polarizing plate, or the like is intended to prevent a decrease in the reflectance due to oxidation and, as a result, a long-lasting initial reflectance. It is more preferable to avoid separately providing a protective layer.
[0050]
The transflective polarizing plate can be obtained by forming a transflective 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. When a liquid crystal display device or the like is used in a relatively bright atmosphere, an image is displayed by reflecting incident light from the viewing side (display side). In a relatively dark atmosphere, a liquid crystal display device of a type that displays an image using a built-in light source such as a backlight built in the back side of a transflective polarizing plate can be formed. That is, the transflective polarizing plate can save energy for use of a light source such as a backlight in a bright atmosphere, and is useful for forming a liquid crystal display device of a type that can be used with a built-in light source even in a relatively dark atmosphere. It is.
[0051]
An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. When changing linearly polarized light to elliptically or circularly polarized light, changing elliptically or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light, a phase difference plate or the like is used. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that converts linearly polarized light into circularly polarized light or converts circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used to change the polarization direction of linearly polarized light.
[0052]
The elliptically polarizing plate compensates (prevents) coloring (blue or yellow) caused by the birefringence of the liquid crystal layer of a super twisted nematic (STN) type liquid crystal display device, and is effectively used for a black-and-white display without the coloring. Can be Further, the one in which the three-dimensional refractive index is controlled is preferable because coloring which occurs when the screen of the liquid crystal display device is viewed from an oblique direction can be compensated (prevented). The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflection type liquid crystal display device that displays an image in color, and also has an antireflection function. As specific examples of the above retardation plate, polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene and other polyolefins, polyarylate, birefringent film obtained by stretching a film made of a suitable polymer such as polyamide And an alignment film of a liquid crystal polymer, and an alignment layer of a liquid crystal polymer supported by a film. The retardation plate may have an appropriate retardation depending on the purpose of use, such as, for example, a color plate due to birefringence of various wave plates or a liquid crystal layer, or a target for compensation of a viewing angle or the like. A retardation plate may be laminated to control optical characteristics such as retardation.
[0053]
Further, the elliptically polarizing plate or the reflection type elliptically polarizing plate is obtained by laminating a polarizing plate or a reflection type polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like may be formed by sequentially and separately laminating a (reflection type) polarizing plate and a retardation plate in the process of manufacturing a liquid crystal display device so as to form a combination. An optical film such as a polarizing plate has an advantage that the stability of quality and laminating workability are excellent and the production efficiency of a liquid crystal display device or the like can be improved.
[0054]
The viewing angle compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed not in a direction perpendicular to the screen but in a slightly oblique direction. Such a viewing angle compensating retardation plate includes, for example, a retardation film, an alignment film such as a liquid crystal polymer, and a transparent substrate on which an alignment layer such as a liquid crystal polymer is supported. The ordinary retardation plate is a polymer film having birefringence uniaxially stretched in the plane direction, whereas the retardation plate used as the viewing angle compensation film is biaxially stretched in the plane direction. A birefringent polymer film such as a polymer film having birefringence or a birefringent polymer such as a birefringent polymer and a birefringent polymer in which the refractive index in the thickness direction is stretched uniaxially in the plane direction and also stretched in the thickness direction and controlled in the thickness direction. Used. Examples of the obliquely oriented film include a film obtained by bonding a heat shrinkable film to a polymer film and subjecting the polymer film to a stretching treatment and / or shrinkage treatment under the action of the shrinkage force caused by heating, and a film obtained by obliquely aligning a liquid crystal polymer. No. As the raw material polymer of the retardation plate, the same polymer as described in the above retardation plate is used to prevent coloring or the like due to a change in the viewing angle based on the phase difference due to the liquid crystal cell and to enlarge the viewing angle for good visibility. Any appropriate one for the purpose can be used.
[0055]
In addition, because of achieving a wide viewing angle with good visibility, the optically-compensated retardation, in which an optically anisotropic layer consisting of an alignment layer of liquid crystal polymer, particularly a tilted alignment layer of discotic liquid crystal polymer, is supported by a triacetyl cellulose film A plate can be preferably used.
[0056]
A polarizing plate obtained by laminating a polarizing plate and a brightness enhancement film is usually used by being provided on the back side of a liquid crystal cell. The brightness enhancement film reflects linearly polarized light of a predetermined polarization axis or circularly polarized light of a predetermined direction when natural light is incident due to reflection from a backlight or a back side of a liquid crystal display device, and has a property of transmitting other light. A polarizing plate obtained by laminating a brightness enhancement film and a polarizing plate, while transmitting light from a light source such as a backlight to obtain a transmission light in a predetermined polarization state, is reflected without transmitting light other than the predetermined polarization state. You. The light reflected on the surface of the brightness enhancement film is further inverted through a reflection layer or the like provided on the rear side thereof and re-incident on the brightness enhancement film, and a part or all of the light is transmitted as light of a predetermined polarization state to thereby obtain brightness. In addition to increasing the amount of light transmitted through the enhancement film, it is also possible to improve the luminance by supplying polarized light that is hardly absorbed by the polarizer to increase the amount of light that can be used for liquid crystal display image display and the like. In other words, when light is incident through the polarizer from the back side of the liquid crystal cell with a backlight or the like without using a brightness enhancement film, light having a polarization direction that does not match the polarization axis of the polarizer is almost completely polarized. Is absorbed by the polarizer and does not pass through the polarizer. That is, although it depends on the characteristics of the polarizer used, about 50% of the light is absorbed by the polarizer, and accordingly, the amount of light available for liquid crystal image display and the like decreases, and the image becomes darker. The brightness enhancement film is such that light having a polarization direction as absorbed by the polarizer is once reflected by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflection layer or the like provided behind the same. The brightness enhancement film transmits only the polarized light whose polarization direction has been changed so that the polarization direction of the light reflected and inverted between the two can pass through the polarizer. Since the light is supplied to the polarizer, light from a backlight or the like can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.
[0057]
A diffusion plate may be provided between the brightness enhancement film and the above-mentioned reflection layer or the like. The light in the polarization state reflected by the brightness enhancement film goes to the reflection layer and the like, but the diffuser provided uniformly diffuses the light passing therethrough, and at the same time, eliminates the polarization state and becomes a non-polarization state. That is, the diffuser returns the polarized light to the original natural light state. The light in the non-polarized state, that is, the light in the natural light state is repeatedly directed to the reflection layer and the like, reflected through the reflection layer and the like, again passed through the diffusion plate and re-incident on the brightness enhancement film. Thus, while maintaining the brightness of the display screen by providing a diffusion plate that returns polarized light to the original natural light state between the brightness enhancement film and the reflective layer, etc., at the same time, reducing unevenness in the brightness of the display screen, A uniform and bright screen can be provided. It is considered that by providing such a diffusion plate, the number of repetitions of the reflection of the first incident light is moderately increased, and a uniform bright display screen can be provided in combination with the diffusion function of the diffusion plate.
[0058]
The brightness enhancement film has a property of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of a dielectric or a multilayer laminate of thin films having different refractive index anisotropies. As shown in the figure, such as a cholesteric liquid crystal polymer oriented film or a film in which the oriented liquid crystal layer is supported on a film substrate, it exhibits a property of reflecting either left-handed or right-handed circularly polarized light and transmitting other light. Any suitable one such as one can be used.
[0059]
Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis, the transmitted light is incident on the polarization plate as it is, with the polarization axis aligned, thereby efficiently transmitting the light while suppressing the absorption loss by the polarization plate. Can be done. On the other hand, in a brightness enhancement film of the type that emits circularly polarized light, such as a cholesteric liquid crystal layer, it can be directly incident on a polarizer, but from the viewpoint of suppressing absorption loss, the circularly polarized light is linearly polarized through a retardation plate. It is preferable that the light is incident on a polarizing plate. By using a quarter-wave plate as the retardation plate, circularly polarized light can be converted to linearly polarized light.
[0060]
A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region exhibits, for example, a retardation layer that functions as a quarter-wave plate for light-color light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method of superimposing a retardation layer, for example, a retardation layer functioning as a half-wave plate. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.
[0061]
The cholesteric liquid crystal layer is also configured such that two or three or more cholesteric liquid crystal layers are superimposed on each other to reflect circularly polarized light in a wide wavelength range such as a visible light region. Based on this, it is possible to obtain circularly polarized light transmitted in a wide wavelength range.
[0062]
Further, the polarizing plate may be formed by laminating a polarizing plate and two or three or more optical layers as in the above-mentioned polarized light separating type polarizing plate. Therefore, a reflective elliptically polarizing plate or a transflective elliptically polarizing plate obtained by combining the above-mentioned reflective polarizing plate, semi-transmissive polarizing plate, and retardation plate may be used.
[0063]
The lamination of the hard coat film on the optical element and the lamination of various optical layers on the polarizing plate can also be carried out by a method of sequentially laminating them sequentially in the process of manufacturing a liquid crystal display device or the like. The layered structure is excellent in quality stability, assembling work, and the like, and has an advantage that a manufacturing process of a liquid crystal display device or the like can be improved. Appropriate bonding means such as an adhesive layer can be used for lamination. When bonding the polarizing plate and other optical films, their optical axes can be set at an appropriate angle depending on the intended retardation characteristics and the like.
[0064]
The hard coat film is provided on at least one surface of an optical element such as the above-described polarizing plate or an optical film in which at least one polarizing plate is laminated, but the surface on which the hard coat film is not provided is provided. An adhesive layer for bonding to other members such as a liquid crystal cell can also be provided. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited, and for example, an acrylic polymer, a silicone-based polymer, a polyester, a polyurethane, a polyamide, a polyether, and a polymer having a fluorine-based or rubber-based polymer as a base polymer are appropriately selected. Can be used. In particular, an acrylic adhesive having excellent optical transparency, exhibiting appropriate wettability, cohesiveness and adhesive adhesive properties and having excellent weather resistance and heat resistance can be preferably used.
[0065]
In addition to the above, prevention of foaming and peeling phenomena due to moisture absorption, reduction of optical characteristics due to thermal expansion difference and the like, prevention of warpage of the liquid crystal cell, and, in view of the formability of a liquid crystal display device having high quality and excellent durability, etc. An adhesive layer having low moisture absorption and excellent heat resistance is preferred.
[0066]
The adhesive layer is, for example, a natural or synthetic resin, in particular, a tackifier resin, or a filler, a pigment, a colorant, an antioxidant, or the like made of glass fiber, glass beads, metal powder, other inorganic powder, and the like. May be added to the pressure-sensitive adhesive layer. In addition, an adhesive layer containing fine particles and exhibiting light diffusibility may be used.
[0067]
The attachment of the adhesive layer to an optical element such as a polarizing plate or an optical film can be performed by an appropriate method. As an example thereof, for example, an adhesive solution of about 10 to 40% by weight is prepared by dissolving or dispersing a base polymer or a composition thereof in a solvent composed of a single solvent or a mixture of appropriate solvents such as toluene and ethyl acetate, A method of directly attaching it to the optical element by an appropriate development method such as a casting method or a coating method, or a method of forming an adhesive layer on a separator according to the above and transferring it to the optical element. can give. The pressure-sensitive adhesive layer can be provided as a superposed layer of different compositions or types of layers. The thickness of the pressure-sensitive adhesive layer can be appropriately determined depending on the purpose of use, adhesive strength, and the like, and is generally 1 to 500 µm, preferably 5 to 200 µm, particularly preferably 10 to 100 µm.
[0068]
A separator is temporarily attached to the exposed surface of the adhesive layer for the purpose of preventing contamination and the like until the adhesive layer is put to practical use and covered. This can prevent the adhesive layer from coming into contact with the adhesive layer in a normal handling state. Except for the above thickness conditions, the separator may be, for example, a plastic film, a rubber sheet, paper, cloth, a nonwoven fabric, a net, a foamed sheet or a metal foil, a suitable thin sheet such as a laminate thereof, or a silicone-based material as necessary. Appropriate conventional ones, such as those coated with an appropriate release agent such as a long-chain alkyl-based, fluorine-based, or molybdenum sulfide, may be used.
[0069]
In the present invention, for example, a polarizer, a transparent protective film, an optical layer, or the like forming the above-described optical element, and each layer such as an adhesive layer, for example, a salicylate compound, a benzophenol compound, a benzotriazole compound, or a cyanoacrylate. It may be a compound having an ultraviolet absorbing ability by a method such as a method of treating with an ultraviolet absorbent such as a system compound and a nickel complex compound.
[0070]
The optical element provided with the hard coat film of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The formation of the liquid crystal display device can be performed according to a conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell and an optical element and, if necessary, an illumination system and incorporating a drive circuit. There is no particular limitation except that an element is used, and it can be in accordance with the prior art. As for the liquid crystal cell, any type such as TN type, STN type and π type can be used.
[0071]
An appropriate liquid crystal display device such as a liquid crystal display device in which the optical element is arranged on one side or both sides of a liquid crystal cell, or an illumination system using a backlight or a reflector can be formed. In that case, the optical element according to the present invention can be installed on one side or both sides of the liquid crystal cell. When optical elements are provided on both sides, they may be the same or different. Further, when forming the liquid crystal display device, for example, a suitable component such as a diffusion plate, an anti-glare layer, an antireflection film, a protection plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, etc. Two or more layers can be arranged.
[0072]
Next, an organic electroluminescence device (organic EL display device) will be described. In general, in an organic EL display device, a luminous body (organic electroluminescent luminous body) is formed by sequentially laminating a transparent electrode, an organic luminescent layer, and a metal electrode on a transparent substrate. Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative or the like, and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a configuration having various combinations such as a stacked body of such a light emitting layer and an electron injection layer made of a perylene derivative, or a stacked body of a hole injection layer, a light emitting layer, and an electron injection layer thereof is known. Has been.
[0073]
In an organic EL display device, holes and electrons are injected into an organic light emitting layer by applying a voltage to a transparent electrode and a metal electrode, and energy generated by recombination of these holes and electrons excites a fluorescent substance. Then, light is emitted on the principle that the excited fluorescent substance emits light when returning to the ground state. The mechanism of recombination on the way is the same as that of a general diode, and as can be expected from this, the current and the emission intensity show strong nonlinearity accompanied by rectification with respect to the applied voltage.
[0074]
In an organic EL display device, at least one of the electrodes must be transparent in order to extract light emitted from the organic light emitting layer. Usually, a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. 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 a metal electrode such as Mg-Ag or Al-Li is used.
[0075]
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. Therefore, the organic light emitting layer transmits light almost completely, similarly to the transparent electrode. As a result, when light is incident from the surface of the transparent substrate during non-light emission, light transmitted through the transparent electrode and the organic light-emitting layer and reflected by the metal electrode again exits to the surface side of the transparent substrate, and when viewed from the outside, The display surface of the organic EL display device looks like a mirror surface.
[0076]
In an organic EL display device including an organic electroluminescent luminous body having a transparent electrode on the front side of an organic luminescent layer that emits light by applying a voltage and a metal electrode on the back side of the organic luminescent layer, the surface of the transparent electrode A polarizing plate can be provided on the side, and a retardation plate can be provided between the transparent electrode and the polarizing plate.
[0077]
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 polarizing function. In particular, if the retardation plate is formed of a 1/4 wavelength plate and the angle between the polarization directions of the polarizing plate and the retardation plate is adjusted to π / 4, the mirror surface of the metal electrode can be completely shielded. .
[0078]
That is, as for the external light incident on the organic EL display device, only the linearly polarized light component is transmitted by the polarizing plate. This linearly polarized light is generally converted into elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a １ wavelength plate and the angle between the polarization directions of the polarizing plate and the phase difference plate is π / 4. .
[0079]
This circularly polarized light transmits through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, passes through the organic thin film, the transparent electrode, and the transparent substrate again, and becomes linearly polarized light again by the phase difference plate. The linearly polarized light cannot pass through the polarizing plate because it is orthogonal to the polarizing direction of the polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.
[0080]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. In each case, parts and% are based on weight. The measurement of the refractive index of the present invention was performed using an Abbe refractometer manufactured by Atago Co., Ltd.
[0081]
Example 1
(Preparation of hard coat layer forming material)
Tetraalkoxysilane (refractive index: 1.45) and ATO ultrafine particles having a particle diameter of 0.01 to 0.1 μm are mixed at a weight ratio of the former: the latter = 1: 7 and dissolved in a solvent containing ethanol as a main component. Thus, a coating solution 1 having a solid concentration of 2% was prepared.
[0082]
On the other hand, 100 parts of an acrylic ultraviolet curable resin (refractive index 1.52), 70 parts of ZrO ₂ having an average particle diameter of 0.01 to 0.1 μm, and 5 parts of an ultraviolet polymerization initiator (benzophenone) are used as a solvent (toluene). A coating solution 2 having a solid content concentration of 40% was prepared. The coating liquid 1 and the coating liquid 2 were mixed at a weight ratio of former: latter = 1: 1 to prepare a hard coat layer forming agent (resin mixed solution).
[0083]
(Preparation of hard coat film)
An 80 μm-thick triacetyl cellulose film (TAC film: refractive index: 1.49) was used as a transparent base film. The hard coat layer forming agent was applied on a transparent substrate film with a wire bar, and then left for 1 minute to precipitate conductive fine particles on the transparent substrate film side. Thereafter, after drying at 90 ° C. for 3 minutes, a curing treatment was performed by irradiating ultraviolet rays to form a hard coat layer having a thickness of 2 μm to obtain a hard coat film. Further, on the hard coat layer, an ethyl silicate (refractive index: 1.45) solution is applied so as to have a thickness of 0.1 μm after drying, followed by drying and curing treatment to form an anti-reflection layer. Thus, an antireflection hard coat film was obtained.
[0084]
The obtained antireflective hard coat film the section was observed with a TEM are shown in Figure 1, when the ratio of (L 2 _{/ L 1)} 0.1, the hard coat layer 2 in the range of L ₂ It was confirmed that 72% of the ATO fine particles were present, and that an apparent transparent conductive layer was formed. The ratio of the ATO fine particles was determined by performing image processing from a cross section observed by TEM and performing binarization processing. It is considered that the apparent transparent conductive layer has a refractive index of 1.60, and the other hard coat layers have a refractive index of 1.70.
[0085]
Example 2
In the preparation of the coating solution 1 of Example 1, except that tetraalkoxysilane was not added, the ATO ultrafine particles were dissolved in a solvent containing ethanol as a main component to prepare a coating solution 1 having a solid concentration of 2%. A hard coat layer forming material was prepared in the same manner as in Example 1. Using the material for forming a hard coat layer, a hard coat layer and an antireflection layer were formed in the same manner as in Example 1 to obtain an antireflection hard coat film.
[0086]
The obtained antireflective hard coat film the section was observed with a TEM are shown in Figure 1, the ratio when (L 2 _{/ L 1)} is 0.1, in the hard coat layer 2 within the range of L ₂ It was confirmed that 53% of the ATO fine particles were present, and it was confirmed that an apparent transparent conductive layer was formed. The percentage of ATO microparticles was derived from the cross section observed by TEM as before. It is considered that the apparent transparent conductive layer has a refractive index of 1.60, and the other hard coat layers have a refractive index of 1.70.
[0087]
Comparative Example 1
A coating solution 1 prepared in Example 1 was applied to a 80 μm-thick triacetylcellulose film with a bar coater, dried with a solvent, and irradiated with ultraviolet rays to be cured to form a 0.1 μm-thick transparent conductive layer. did. Next, the coating liquid 2 prepared in Example 1 was applied thereon with a bar coater, dried with a solvent, and then irradiated with ultraviolet rays for curing treatment to form a hard coat layer having a thickness of 2 μm. Further, on the hard coat layer, an ethyl silicate (refractive index: 1.45) solution is applied so as to have a thickness of 0.1 μm after drying, followed by drying and curing treatment to form an anti-reflection layer. Thus, an antireflection hard coat film was obtained.
[0088]
Comparative Example 2
In Example 1, an anti-reflection hard coat film was obtained in the same manner as in Example 1, except that the hard coat layer forming agent was applied with a wire bar and allowed to stand for 10 seconds during production of the hard coat film.
[0089]
The following evaluations were performed on the antireflection hard coat films obtained in the above Examples and Comparative Examples. Table 1 shows the results.
[0090]
(Reflectance: Y value)
It is measured based on JIS Z8701 "Color display method using a 2-degree visual field XYZ system". That is, a black acrylic plate (2.0 mm thick) was adhered to the surface of the antireflection hard coat film on which the low refractive index layer was not provided with an adhesive to eliminate reflection on the back surface. Next, the spectral reflectance (specular reflectance + diffuse reflectance) was measured with a spectrophotometer equipped with a Shimadzu UV2400PC / 8 ° tilting integrating sphere to determine the total reflectance (Y value) of the C light source / 2 ° field of view. Was. The conversion from spectral reflectance to total reflectance is based on a calculation program built in the spectrophotometer.
[0091]
(Surface resistance value)
The surface resistance of the anti-reflection layer of the anti-reflection hard coat film was measured. The measurement was performed based on JIS K6911 using a digital ultra-high resistance meter (R8340A) manufactured by Advantest Co., with 500 V applied.
[0092]
(Adhesion)
The grid test evaluation was performed based on JIS K5400, and evaluated according to the following criteria.
：: 6 or more based on JIS evaluation score.
X: 4 or less based on JIS evaluation score.
[0093]
[Table 1]

From Table 1, it can be seen that the antireflection hard coat film of the present invention (Example) has the same reflectance and conductivity as the case where the transparent conductive layer and the hard coat layer are separately formed (Comparative Example 1), and adheres. It is also recognized that the properties are good. In Comparative Example 2, the density of the conductive fine particles is small, and it is difficult to exhibit conductivity.
[Brief description of the drawings]
FIG. 1 is an example of a hard coat film of the present invention.
FIG. 2 is an example of the antireflection hard coat film of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 transparent substrate film 2 hard coat layer 3 conductive fine particles 4 anti-reflection layer

Claims (7)

In a hard coat film having a hard coat layer formed of a transparent resin on a transparent substrate film, the conductive fine particles are unevenly distributed in the hard coat layer with a concentration distribution in a thickness direction, and the transparent substrate A hard coat film wherein the concentration of conductive fine particles on the film side is high. _2. The hard coat film according to claim 1, wherein the specific gravity (d ₁ ) of the conductive fine particles is larger than the specific gravity (d ₂ ) of the transparent resin. 3. The hard coat film according to claim 1, wherein the hard coat layer is formed of two or more transparent resins. A hard coat film, wherein an anti-reflection layer is formed on the hard coat layer of the hard coat film according to claim 1. A transparent resin solution containing conductive fine particles is applied on a transparent base film, and the conductive fine particles are allowed to settle on the transparent base film side. Then, the transparent resin is cured to form a hard coat layer. The method for producing a hard coat film according to claim 1. An optical element, wherein the hard coat film according to any one of claims 1 to 4 is provided on one or both sides of the optical element. An image display device comprising the antireflection hard coat film according to claim 1 or the optical element according to claim 6.

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