JP5107527B2 - Plasma display device - Google Patents

Description

  The present invention relates to a plasma display display device that reduces external light reflection on a plasma display and makes an image clear by achieving both natural reflection colors.

In recent years, a plasma display display device using a plasma display panel (PDP) has attracted attention as a large and thin display device such as a television. In this plasma display display device, it is effective to mount an optical filter on the front surface for the purpose of improving visibility and improving impact resistance. However, there is a problem in that it is difficult to see the screen by reflecting high brightness external light such as sunlight or sunlight inserted through a window through the optical filter surface of the display or the internal front glass through the air layer. In order to solve this problem, an attempt has been made to provide an antireflection layer on the front side or the back side of the optical filter, but the reflection cannot be completely removed, and the reflection color is strongly blue or purple. It has not reached a sufficient effect. Patent Document 1 shows an example in which a commercially available antireflection film is attached to the front and back of an optical filter in Example 1 in an optical filter that requires a plurality of functional films. However, according to the study by the present inventors, it has been found that in this example, the antireflection is not sufficient, and the reflected color is amber. On the other hand, in Patent Document 2, there is also a proposal for reducing reflection of external light and preventing double reflection by using an optical film having a light diffusion function and a low reflection function on the front glass. However, the addition of the light diffusing function reduces the resolution of the image quality, and has not achieved both improvement in image quality and prevention of reflection. Furthermore, since there is no specific description about the antireflection layer to be applied to the front and back surfaces of the optical filter, when considering using a commercially available antireflection layer such as Patent Document 1, the antireflection is insufficient. The reflection color is strongly blue and purple.
Japanese Patent No. 3710721 JP 2000-156182 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma display device that reduces reflection caused at the air layer interface constituting a plasma display without reducing the resolution of output image quality, maintains a natural reflected color, and improves visibility. Is.

In order to solve the above-mentioned problems, the present invention solves the above-mentioned problem by using an optical filter installed on the plasma display through an air layer, the viewer side being the A side, the light emitting side of the back side to the B side, and the front glass surface facing the air layer being C If the surface
(1) A plasma display device in which an antireflection layer is disposed on the A side and the B side, wherein the A layer antireflection layer has a minimum reflectance of 0.5% or less and a minimum reflectance wavelength of 520 to 580. In the plasma display device, the minimum reflectance wavelength of the antireflection layer on the B surface is 50 to 150 nm shorter than the minimum reflectance wavelength of the antireflection layer on the A surface.
(2) A plasma display device in which antireflection layers are arranged on the A, B, and C surfaces, wherein the minimum reflectance of the antireflection layer on the A surface is 0.5% or less, and the minimum reflectance wavelength is It is in the range of 520 to 580 nm, and the minimum reflectance wavelength of at least one of the antireflection layers of the B surface and the C surface is 50 to 150 nm shorter than the minimum reflectance wavelength of the antireflection layer on the A surface. It is a plasma display display device.
(3) The average value of the reflectance at a wavelength of 400 to 700 nm of the antireflection layer disposed on the A surface is 2% or less, and the minimum reflectance in the wavelength range of 300 nm to 800 nm is 1% or less. Item 3. The plasma display device according to Item 1 or 2.

  In the plasma display device of the present invention, reflection at the air layer interface is reduced, and natural reflection color is maintained, so that it is easy to view images.

The present invention will be described with reference to FIG.
FIG. 1 includes an optical filter 2 of a plasma display display device and a plasma display panel (hereinafter referred to as PDP) 8. The PDP 8 includes a front glass 5, a plasma emission region 6, and a rear glass 7. In the plasma emission region 6, a discharge space is formed between a pair of glass substrates (5 and 7), and a phosphor layer that emits light by discharge is provided. On the basis of this operation principle, PDP generates strong electromagnetic waves and near infrared rays, so these must be shielded. For example, in the case of electromagnetic waves, it can be shielded by a mesh layer obtained by etching copper foil in a lattice shape, and near infrared rays and ultraviolet rays can be shielded by mixing an absorbent into an adhesive material or film. On the other hand, the display device requires an optical filter having a certain transmittance in order to obtain a contrast in a bright place, and is adjusted by providing a dye layer on the front surface including adjustment with the display color. Therefore, the PDP optical filter has functions of shielding electromagnetic waves, near infrared rays, etc., adjusting color tone, and adjusting contrast. Further, since the display portion of the PDP is generally low in strength, it is necessary to protect it, and the optical filter also has a function as a protective layer. In some cases, such an optical filter requiring multi-functionality may be directly attached to the surface of the PDP, but in many cases, it is provided as an optical filter on the front surface of the PDP through an air layer from the viewpoint of protecting the PDP display unit. The present invention relates to a plasma display display device in which an optical filter is installed via an air layer, the viewer side of the optical filter 2 in FIG. 1 is the A surface, the back surface (light emitting side) of the optical filter is the B surface, The air layer side of the front glass 5 is expressed as a C plane.

The present invention relates to a plasma display device in which an antireflection layer is disposed on the A side and the B side, wherein the minimum reflectance wavelength of the antireflection layer on the A side is in the range of 500 to 600 nm, and the antireflection on the B side. The plasma display device is characterized in that the minimum reflectance wavelength of the layer is 50 to 150 nm shorter than the minimum reflectance wavelength of the antireflection layer on the A surface.
As the antireflection layer, one having a single layer or a multilayer structure is known. Among these, the multilayer structure by a dry process such as sputtering or vacuum deposition has the disadvantages that the optical characteristics are excellent, but the process is complicated and the productivity is low. In the present invention, a dry process may be used, but in view of industrial productivity, a wet process by coating is preferred. An antireflective film excellent in antireflective performance can be provided by a one-layer or two-layer structure using an antireflection film formed by a wet process.

In the present invention, the minimum reflectance wavelength of the antireflection layer on the A surface is in the range of 500 to 600 nm. By setting the wavelength of the minimum reflectance to 500 to 600 nm, the reflected color is close to natural light, and the antireflection performance is excellent. From the viewpoint of making it closer to the natural light of the internal reflection color and the color of the reflection color when the observation angle becomes wide, a more preferable wavelength is 520 to 580 nm.
It is a preferable aspect that the visible light average reflectance of the antireflection layer disposed on the A surface is 2% or less and the minimum reflectance is 1% or less. The visible light average reflectance is further preferably 1% or less. If the visible light average reflectance is low, the reflectance in the entire visible light range is low, so the antireflection performance is high, and the reflected color is close to natural light because it is not biased. preferable. Moreover, the minimum reflectance wavelength is 500-600 nm, and the thing with the minimum minimum reflectance is excellent in antireflection performance from a viewpoint of human visibility, and is preferable. Among these, those having a minimum reflectance of 0.5% or less are particularly excellent in antireflection performance.

On the other hand, since the antireflection layer on the A side is the outermost surface of the display device, it is preferable that its mechanical strength is high. The pencil hardness is preferably H or higher, and particularly preferably 2H or higher. Moreover, since it is the outermost surface, it is preferable that the surface is protected against dust so that dust or the like is not easily attached. This can be achieved by setting the surface resistivity of the antireflection layer on the A surface to 10 ¹⁵ Ω / □ or less.
The antireflection layer on the A side is a transparent substrate / hard coat / high refractive index layer / low refractive index layer or transparent substrate / hard coat / low refractive index layer, which is attached to the A surface using an adhesive. By attaching, it can be arranged on the A side.

As transparent substrates, polyethylene film, polypropylene film, triacetyl cellulose, cellulose acetate film such as cellulose acetate propionate, stretched polyethylene terephthalate, polyester film such as polyethylene naphthalate, polycarbonate film, norbornene film, Polysulfone film, polyethersulfone film, polyarylate film and the like. Of these transparent substrates, from the viewpoint of reducing the visible light average reflectance, a substrate having a refractive index of 1.45 to 1.55 is preferably used, and a TAC film (refractive index 1.49) is most preferable. Used.
The thickness of the transparent substrate is preferably 25 μm or more from the viewpoint of the uniformity of the thickness of the low refractive index layer and the handleability as an optical substrate. A preferred upper limit is 200 μm from the viewpoint of light transmittance and light utilization efficiency.

It is preferable to provide a hard coat layer on the transparent substrate. By providing the hard coat layer, the surface layer of the optical filter can be strengthened and it can be made hard to be damaged. As the hard coat, those having a pencil strength of H or higher in the pencil hardness test according to JISK5400 are preferably used, and those having a hardness of 2H or higher are particularly preferably used.
Typical materials for the hard coat are melamine, acryl radical, acryl silicone, and alkoxy silane, and organic and / or inorganic fine particles dispersed in the hard coat material as a matrix (hereinafter referred to as organic). (It is also possible to use an inorganic particle dispersion system).

Among the above hard coat materials, the acrylic radical system is preferably a polymer obtained by polymerizing a polyfunctional acrylate oligomer and / or a polyfunctional acrylate monomer. Examples of the polyfunctional acrylate monomer include dipentaerythritol hexaacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and ditrimethylolpropane tetraacrylate.
Polyfunctional acrylate oligomers include epoxy acrylates that are acrylate-modified novolak-type and bisphenol-type epoxy resins, urethane acrylates that are acrylate-modified products of urethane compounds obtained by reacting polyisocyanates and polyols, and polyester acrylates that are acrylate-modified polyester resins. Etc.

Moreover, in the acrylic silicone type | system | group, what bonded the acrylic group by the covalent bond on the silicone resin is preferable.
Moreover, in the alkoxysilane type | system | group, what contains the condensate which has the silanol group obtained by carrying out the hydrolysis polycondensation of alkoxysilane is preferable. A silanol group is converted into a siloxane bond by thermosetting after coating, and a cured film is obtained.
The hard coat layer is preferably a hard coat material capable of performing heat curing, ultraviolet curing, and electron beam curing. The hard coat material preferably contains a photopolymerization initiator, a thermal polymerization initiator, an additive, a solvent and the like depending on the curing method.

  Examples of inorganic particles used in the above organic / inorganic particle dispersion include silicon dioxide particles, titanium dioxide particles, aluminum oxide particles, zirconium oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc, kaolin and sulfuric acid. A calcium particle is mentioned. Examples of organic particles include methacrylic acid-methyl acrylate copolymer, silicone resin, polystyrene, polycarbonate, acrylic acid-styrene copolymer, benzoguanamine resin, melamine resin, polyolefin, polyester, polyamide, polyimide, and polyfluorinated ethylene. The average particle diameter of these particles is preferably 0.01 to 5 μm, and more preferably 0.01 to 0.3 μm. A plurality of organic particles and inorganic particles may be mixed and used, or a mixture of organic particles and inorganic particles may be used.

The organic particles and inorganic particles that can be used in the present invention may or may not be chemically bonded to the hard coat material used as a matrix. The organic / inorganic particle-dispersed hard coat material has a function of increasing the hardness of the hard coat layer and suppressing curing shrinkage by dispersing the particles in the hard coat material.
Specific examples of the inorganic particle dispersion system include an acrylic radical system in which inorganic fine particles are dispersed, an organic polymer system in which inorganic fine particles are dispersed, an organoalkoxysilane system in which inorganic fine particles are dispersed, and the like. What disperse | distributed silica, titanium oxide, an alumina, etc. is preferable. Further, it is also preferable to use fine particles in which the surface of the silica particles is modified with an acryloyl group or the like.

In addition to the hard coat layer, colorants (pigments, dyes), antifoaming agents, thickeners, leveling agents, flame retardants, UV absorbers, antistatic agents, antioxidants and modifying resins are added. Also good.
As the antistatic agent, those obtained by dispersing a known antistatic agent such as a surfactant or an ionic polymer or conductive fine particles in a binder are used. Examples of the conductive fine particles include oxide or composite oxide fine particles such as indium, zinc, tin, molybdenum, antimony, and gallium, copper, silver, nickel, low melting point alloy (solder, etc.) metal fine particles, and a metal-coated polymer. Known materials such as fine particles, various kinds of carbon black, conductive polymer particles such as polypyrrole and polyaniline, metal fibers, and carbon fibers can be used. Among these, ITO (tin-containing indium oxide) particles, ATO (tin-containing antimony oxide) particles, and antimony pentoxide particles are particularly preferable because they can exhibit high transparency and conductivity.
It is also preferable when the hard coat layer is surface-modified. The surface modification treatment is preferably treatment using corona treatment, deep-UV irradiation, excimer lamp irradiation, vacuum plasma treatment, atmospheric pressure plasma treatment, electron beam irradiation, primer treatment containing a silane coupling agent, or the like.

  For coating the hard coat layer, a composition obtained by adding additives as necessary to the above hard coat material is applied on a transparent plastic substrate as a coating solution using a solvent as necessary, and is formed and cured. Can be manufactured. Solvents include water, methanol, ethanol, isopropanol, butanol, benzyl alcohol and other alcohols, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and other ketones, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, Esters such as ethyl formate, propyl formate and butyl formate, aliphatic hydrocarbons such as hexane and cyclohexane, halogenated hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride, and aromatic carbonization such as benzene, toluene and xylene Hydrogens, amides such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, diethyl ether, dioxane, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol dimethyl Ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, solvent ethers such as propylene glycol dimethyl ether, preferably toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol.

The hard coat layer can be obtained by coating and drying and then heating and curing at 80 to 150 ° C. or curing using light or an electron beam.
The hard coat material that can be used in the present invention has been described above, but as the hard coat material that can be used in the present invention, a commercially available silicone hard coat, (meth) acrylic hard coat, epoxy hard coat, Known materials such as urethane hard coat, epoxy acrylate hard coat, and urethane acrylate hard coat can be used. Specifically, Shin-Etsu Chemical Co., Ltd. UV curable silicone hard coat agent X-12 series, GE Toshiba Silicone Co., Ltd. UV curable silicone hard coat agent UVHC series, thermosetting silicone hard coat agent SHC series, stock A thermosetting silicone hard coat agent Solguard NP series manufactured by Nippon Dacro Shamrock Co., Ltd. and a UV curable hard coat agent KAYANOVA FOP series manufactured by Nippon Kayaku Co., Ltd. are preferred. In addition, it can be formed by applying a coating liquid containing a polyfunctional monomer and a polymerization initiator and polymerizing the polyfunctional monomer. The thickness of the hard coat layer is usually set to 0.1 μm to 5 μm.

Application of the coating composition is a known dipping, spin coater, knife coater, bar coater, blade coater, squeeze coater, reverse roll coater, gravure roll coater, slide coater, curtain coater, spray coater, die coater, cap coater, etc. It can be implemented using a method. Of these, knife coaters, bar coaters, blade coaters, squeeze coaters, reverse roll coaters, gravure roll coaters, slide coaters, curtain coaters, spray coaters, die coaters and cap coaters that can be continuously applied are preferably used.
When a transparent substrate having a refractive index of 1.45 to 1.55 is used and a transparent substrate / hard coat / low refractive index layer is used, the refractive index of the hard coat is 1. It is preferable to set it to 45-1.55. In this configuration, it is preferable to provide the hard coat with an antistatic function. By mixing the conductive fine particles and the low refractive index fine particles, the antistatic function and the refractive index can be adjusted, and the pencil strength can be 2H or more. On the other hand, in the case of a transparent substrate / hard coat / high refractive index layer / low refractive index layer, the refractive index of the hard coat layer is preferably adjusted to 1.55 to 1.70 from the viewpoint of reflectance. . In the case of this configuration, an antistatic function can be imparted to the high refractive index layer.

The low refractive index layer of the antireflection layer on the A side is preferably adjusted to have a refractive index of 1.20 to 1.40, particularly 1.20 to 1.35. Since it has such a refractive index, the average reflectance of visible light can be reduced, and the transfer of external light on the surface layer can be greatly reduced.
Such a low refractive index layer preferably has a refractive index of 1.53 or less as a binder. A binder having a low refractive index is useful for lowering the refractive index. In addition, it is preferable to mix low refractive index fine particles such as hollow silica fine particles. By mixing the refractive index of the binder and the low refractive index fine particles such as hollow silica fine particles, the refractive index of the low refractive index layer can be adjusted.

The hollow silica fine particles are fine particles having cavities therein, and the hollow silica fine particles themselves have a low refractive index (for example, refractive index = 1.10 to 1.35). Since the cavity is surrounded by the outer shell, the binder does not enter the cavity. The presence of this cavity can reduce the refractive index, and the blocking of the binder from entering the cavity can prevent an increase in the refractive index. A function as a prevention film can be realized.
Specifically, it is preferable to use hollow silica fine particles having a refractive index of 1.10 to 1.35 and an average particle size of 30 to 300 nm, particularly 40 to 200 nm. The refractive index of the hollow silica fine particles is preferably 1.10 or more from the viewpoint of the strength of the particles themselves. The refractive index is preferably 1.35 or less, more preferably 1.30 or less, and most preferably 1.26 or less from the viewpoint of obtaining a sufficient antireflection function. The refractive index of the hollow silica fine particles can be adjusted by the void ratio of the cavity, and can be adjusted by the thickness of the outer shell and the particle size.

The outer diameter (average particle diameter) of the hollow silica fine particles is preferably 30 nm or more from the viewpoints of dispersibility, surface properties of the resulting layer, antireflection performance, and strength. The upper limit of the outer diameter of the hollow silica fine particles is preferably 200 nm or less from the viewpoints of antireflection performance, resolution of the fluoroscopic image, and visibility. It is also preferable to use a mixture of hollow silica fine particles and ultrafine particles such as silica having a particle diameter of 20 nm or less. The strength of the low refractive index layer can be improved by mixing with ultrafine particles.
The binder for the low refractive index layer may be used alone or in combination. Preferred binders include the following.

(1) Tetramethoxysilane, tetraethoxysilane, tetra (i-propoxy) silane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxy Silane, propyltriethoxysilane, isobutyltriethoxysilane, methyltri-iso-propoxysilane, ethyltri-iso-propoxysilane, dimethoxysilane, diethoxysilane, methyldimethoxysilane, methyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane Diethyldimethoxysilane, diethyldiethoxysilane, diethyldi (i-propoxy) silane, methylethyldimethoxysilane, methylethyldiethoxysilane , Methylethyldi (i-propoxy) silane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, methylpropyldi (i-propoxy) silane, methoxysilane, ethoxysilane, methylmethoxysilane, methylethoxysilane, dimethylmethoxysilane, dimethyl Ethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, trimethyl (i-propoxy) silane, triethylmethoxysilane, triethylethoxysilane, triethyl (i-propoxy) silane, tripropylmethoxysilane, tripropylethoxysilane, tripropyl (i- Propoxy) silane, methyldiethylmethoxysilane, methyldiethylethoxysilane, methyldiethyl (i-propoxy) silane, methyldipropylmeth Sisilane, methyldipropylethoxysilane, methyldipropyl (i-propoxy) silane, ethyldimethylethoxysilane, ethyldimethyl (i-propoxy) silane, ethyldipropylmethoxysilane, ethyldipropylethoxysilane, ethyldipropyl (i- Propoxy) silane, propyldimethylmethoxysilane, propyldimethylethoxysilane, propyldimethyl (i-propoxy) silane, propyldiethylmethoxysilane, propyldiethylethoxysilane, propyldiethyl (i-propoxy) silane, bis (trimethoxysilyl) methane, Bis (triethoxysilyl) methane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,3-bis ( Triethoxysilyl) propane, hexamethoxydisiloxane, hexaethoxydisiloxane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- Mercaptopropyltriethoxysilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltri Ethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, tetraacetoxysilane, tetrakis (trichloroacetoxy) silane, tetrakis (trifluoroacetate) Xyl) silane, triacetoxysilane, tris (trichloroacetoxy) silane, tris (trifluoroacetoxy) silane, methyltriacetoxysilane, methyltris (trichloroacetoxy) silane, methyltris (trifluoroacetoxy) silane, methyldiacetoxysilane, methylbis ( Trichloroacetoxy) silane, methylbis (trifluoroacetoxy) silane, dimethylbis (trichloroacetoxy) silane, dimethylbis (trifluoroacetoxy) silane, methylacetoxysilane, methyl (trichloroacetoxy) silane, methyl (trifluoroacetoxy) silane, dimethyl Acetoxysilane, dimethyl (trichloroacetoxy) silane, dimethyl (trifluoroacetoxy) silane, trimethylacetoxy Run, trimethyl (trichloroacetoxy) silane, trimethyl (trifluoroacetoxy) silane, tetrachlorosilane, tetrabromosilane, tetrafluorosilane, trichlorosilane, tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltri Fluorosilane, methyldichlorosilane, methyldibromosilane, methyldifluorosilane, dimethyldichlorosilane, dimethyldibromosilane, dimethyldifluorosilane, methylchlorosilane, methylbromosilane, methylfluorosilane, dimethylchlorosilane, dimethylbromosilane, dimethylfluorosilane, trimethyl Reacted with hydrolyzable silanes such as chlorosilane, trimethylbromosilane, trimethylfluorosilane It is. In the case of using hollow silica fine particles, the reaction is preferably carried out by dehydration condensation after the reaction.

(2) 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriacetoxysilane, 3-acryloxypropyltris (trichloroacetoxy) silane, 3-acryloxypropyltris (trifluoroacetoxy) silane, 3-methacryloxypropyltriacetoxy Silane, 3-methacryloxypropyltris (trichloroacetoxy) silane, 3-methacryloxypropyltris (trifluoroacetoxy) silane, 3-glycidoxypropyltriacetoxysila 3-glycidoxypropyltris (trichloroacetoxy) silane, 3-glycidoxypropyltris (trifluoroacetoxy) silane, 3-acryloxypropyltrichlorosilane, 3-acryloxypropyltribromosilane, 3-acryloxypropyl Trifluorosilane, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropyltribromosilane, 3-methacryloxypropyltrifluorosilane, 3-glycidoxypropyltrichlorosilane, 3-glycidoxypropyltribromosilane, Reactive silanes having both a polymerizable functional group and a functional group capable of forming a covalent bond with silica particles in the same molecule, such as 3-glycidoxypropyl trifluorosilane, and these were reacted Things . In the reaction, the polymerizable functional group portion can be polymerized after covalently bonding them with inorganic fine particles such as hollow silica fine particles.

(3) Silicic acid, trimethylsilanol, triphenylsilanol, dimethylsilanediol, diphenylsilanediol, silanol terminated polydimethylsiloxane, silanol terminated polydiphenylsiloxane, silanol terminated polymethylphenylsiloxane, silanol terminated polymethyl ladder siloxane, silanol terminated poly Silicon compounds containing silanol groups such as phenyl ladder siloxane and octahydroxy octasilsesquioxane.

(4) Water glass, sodium orthosilicate, potassium orthosilicate, lithium orthosilicate, sodium metasilicate, potassium metasilicate, lithium metasilicate, tetramethylammonium orthosilicate, tetrapropylammonium orthosilicate, tetramethylammonium metasilicate, metasilicate Active silica obtained by bringing a silicate such as tetrapropylammonium into contact with an acid or ion exchange resin.

(5) Polyethers such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, polyacrylamide derivatives, polymethacrylamide derivatives, amides such as poly (N-vinylpyrrolidone) and poly (N-acylethyleneimine), polyvinyl Organic polymers such as alcohols, polyvinyl acetate, polyacrylic acid derivatives, polymethacrylic acid derivatives, esters such as polycaprolactone, polyimides, polyurethanes, polyureas, and polycarbonates. These organic polymers may have a polymerizable functional group at the terminal or main chain.

(6) alkyl (meth) acrylate, alkylene bis (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Polymerized acrylic monomers such as dipentaerythritol hexa (meth) acrylate. Polymerizable monomers such as alkylene bisglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, pentaerythritol tetraglycidyl ether, vinylcyclohexene diepoxide. Here, (meth) acrylate refers to both acrylate and methacrylate. These are polymers.

(7) A known curable resin. For example, (meth) acrylic UV curable resin, moisture curable silicone resin, thermosetting silicone resin, epoxy resin, phenoxy resin, novolac resin, silicone acrylate resin, melamine resin, phenol resin, unsaturated polyester resin , Polyimide resin, urethane resin, urea resin and the like.

(8) The alkyl groups and hydrogen groups in the above (1) to (7) can be substituted with fluorine. Those substituted with fluorine have a low refractive index and excellent optical performance. However, since it may be mechanically weak alone, it can be used by mixing with inorganic fine particles.
The binder may be used alone or in combination. In particular, reactive silanes having both a polymerizable functional group and a functional group capable of forming a covalent bond with a silica particle in the same molecule listed in (2) are used in combination, or listed in (6). Use of a polymerizable monomer in combination is effective in improving mechanical strength.

  The kind of the polymerizable monomer is appropriately selected according to the form and speed of the reaction. When using a polymerizable monomer or one having a functional group, it is effective to add a polymerization initiator as an additive. As the polymerization initiator, a known one such as a thermal radical generator, a photo radical generator, a thermal acid generator, or a photo acid generator can be selected according to the reaction mode of the above polymerizable functional group or polymerizable monomer. it can.

  Specific examples of the heat / photo radical generator include Irgacure (registered trademark) and Darocur (registered trademark) acetophenone-based, benzophenone-based, phosphine oxide-based, and titanocene-based commercially available from Ciba Specialty Chemicals Co., Ltd. Each polymerization initiator, a thioxanthone polymerization initiator, a diazo polymerization initiator, an o-acyloxime polymerization initiator, and the like can be mentioned. Among these, polymerization initiators having an amino group and / or a morpholino group in the molecule such as Irgacure (registered trademark) 907, Irgacure (registered trademark) 369, and Irgacure (registered trademark) 379 are particularly preferable. Specific examples of the heat / photoacid generator include Sun Aid (trademark) SI series commercially available from Sanshin Chemical Industry Co., Ltd., WPI series, WPAG series, and Sigma Aldrich commercially available from Wako Pure Chemical Industries, Ltd. Examples thereof include sulfonium-based, iodonium-based, and diazomethane-based polymerization initiators represented by the PAGs series commercially available from Japan Corporation.

  The silanes represented by (1) and (2) are preferably used after partial hydrolysis / dehydration condensation. Partial hydrolysis and dehydration condensation reactions are carried out by reacting hydrolyzable silane with water, but as catalysts, acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, formic acid, acetic acid, ammonia, trialkylamine Alkalis such as sodium hydroxide, potassium hydroxide, choline and tetraalkylammonium hydroxide, and tin compounds such as dibutyltin dilaurate may be used. In that case, when using inorganic particles such as hollow silica fine particles, it is preferable to perform a hydrolysis / dehydration condensation reaction in the presence of these inorganic particles. By performing hydrolysis in the presence of the inorganic particles in this way, it is possible to surely create many covalent bonds with the inorganic particles, and the mechanical strength of the low refractive index layer can be improved.

The thickness of the low refractive index layer is usually 50 to 200 nm, more preferably 50 to 150 nm, from the viewpoint of antireflection performance in the visible light region. Within such a range, it can be adjusted according to the refractive index of the low refractive index layer so that the minimum reflectance wavelength is 500 to 600 nm. The wavelength of the minimum reflectance can be adjusted by the refractive index of other layers (such as hard coat).
The method for producing the low refractive index layer is not limited, and when coated on an optical substrate using the coating composition, the content of inorganic particles such as hollow silica fine particles, the concentration of the coating liquid, the types of binders and additives And it can manufacture by controlling those density | concentrations, the coating method, a coating condition, etc.

Application of the coating composition is a known dipping, spin coater, knife coater, bar coater, blade coater, squeeze coater, reverse roll coater, gravure roll coater, slide coater, curtain coater, spray coater, die coater, cap coater, etc. It can be implemented using a method. Of these, knife coaters, bar coaters, blade coaters, squeeze coaters, reverse roll coaters, gravure roll coaters, slide coaters, curtain coaters, spray coaters, die coaters and cap coaters that can be continuously applied are preferably used.
After applying the above coating composition, it is effective to heat in order to volatilize the dispersion medium and to condense and crosslink between the silica particles and the binder component. The heating temperature and time are determined by the heat resistance of the substrate. For example, when a plastic substrate is used as the optical substrate, the heating temperature is selected from 50 ° C. to 200 ° C., and the time is selected from 1 second to 1 hour, preferably in the range of 80 ° C. to 150 ° C., 10 seconds to 3 minutes. It is. Moreover, when the said binder has radiation curability, an ultraviolet-ray, an electron beam, etc. are irradiated by a well-known method.

The low refractive index layer can contain various additives such as an antistatic agent, an ultraviolet absorber, an infrared absorber, a leveling agent, a dye, a metal salt, a surfactant, and a release agent.
A coating layer may be provided for imparting slipperiness or antifouling property to the surface of the antireflection layer. The coating layer is, for example, a fluororesin, a moisture curable silicone resin, a thermosetting silicone resin, silicon dioxide, a (meth) acrylic resin, a (meth) acrylic UV curable resin, an epoxy resin, a phenoxy resin, a novolac resin, It is made of any known material such as silicone acrylate resin, melamine resin, phenol resin, unsaturated polyester resin, polyimide resin, urethane resin, urea resin. The film thickness of the coating layer is usually 50 nm or less, preferably 10 nm or less, more preferably 1 nm or more and 5 nm or less. The coating layer may be composed of a single layer or a plurality of layers. Among these, a fluororesin, a moisture curable silicone resin, and a thermosetting silicone resin are preferable in order to exhibit an antifouling effect.

  It is also possible to provide a high refractive index layer immediately below the low refractive index layer. As the high refractive index layer, for example, known inorganic fine particles such as oxides or composite oxides made of metals such as titanium, zirconium, zinc, antimony, indium, tin, cerium, tantalum, yttrium, hafnium, aluminum, and magnesium are used. The one dispersed in is used. As the binder, those listed in the above (1) to (8) can be used as the binder for the low refractive index layer. Among them, the organic polymer described in (5) is preferably polymerized on the side chain or the terminal. A polymerizable monomer described in (6), and a curable resin described in (7). As the type and amount of these binders, known ones can be used depending on the desired refractive index, strength, light resistance, yellowing and the like. The refractive index of the high refractive index layer is preferably 1.55 to 1.68 in terms of antireflection performance, and particularly preferably 1.57 to 1.65. The thickness of the high refractive index layer is preferably 50 to 300 nm, particularly preferably 120 to 180 nm. By controlling the thickness, it is possible to control the reflectance and the color of the antireflection film.

  In the present invention, when antireflection layers are arranged on the A and B surfaces, the minimum reflectance wavelength of the antireflection layer on the A surface is in the range of 500 to 600 nm, and the minimum reflectance wavelength of the antireflection layer on the B surface is Is shorter by 50 to 150 nm than the minimum reflectance wavelength of the antireflection layer on the A surface. Since the minimum reflectance wavelength of the antireflection layer on the B surface is 50 to 150 nm shorter than the minimum reflectance wavelength on the A surface, reflection can be reduced without causing strong blue or purple in the reflected light. When the minimum reflectance wavelength of the A surface and the minimum reflectance wavelength of the B surface are close, the intensity of the short wavelength and long wavelength of the visible light is relatively higher than the minimum reflectance wavelength. Even with a high reflectance, it is easy to see and be colored by human eyes.

The B-surface antireflection layer preferably has an average visible light reflectance of 2% or less and a minimum reflectance of 1% or less, and particularly preferably has a minimum reflectance of 0.5% or less. is there. If the average visible light reflectance is low, the reflectance in the entire visible light range is low, the antireflection performance is high, and since it is not biased, it becomes a reflection color close to a natural color. In addition, since the minimum reflectance is 1% or less and the minimum reflectance wavelength is 50 to 150 nm shorter than the antireflection film on the A surface, there is no color bias due to the interaction with the A surface, and the reflective performance is exhibited. To do.
As a function required for the antireflection layer on the B surface, unlike the A surface, the mechanical strength and antifouling property may be less than those on the A surface. Therefore, it is also one of preferable embodiments to use a simple structure of transparent substrate / low refractive index layer as the layer structure. Although it may have the same layer structure as the antireflection layer on the A surface, a simple layer structure can greatly improve the production efficiency. As a transparent base material, the same thing as the antireflection layer of A side can be used. Further, a layer structure of transparent base material / hard coat / low refractive index may be used. In that case, the thickness of the hard coat layer can be 2 μm or less, preferably 0.2 μm to 1.5 μm. . As the hard coat layer, the same layer as the A-side antireflection layer can be used.

Since the low refractive index layer of the antireflection layer on the B surface can be easily used even if the mechanical strength is low, the low refractive index layer may not be dense and may be porous. For the low refractive index layer, the same material as that of the low refractive index layer of the antireflection layer on the A surface can be used. A refractive index having the same range as that of the A-plane can be used.
As the antireflection layer on the B surface, a pencil strength of 6B to 4H may be used. Further, a surface resistivity of 10 ¹⁶ Ω / □ or more can also be used. Although care must be taken to prevent dust adhesion and damage when assembling the plasma display device, a simple structure may be adopted for the assembled one because no physical external force is applied to the B side.

  In the present invention, when antireflection layers are arranged on the A, B, and C surfaces, the minimum reflectance wavelength of the antireflection layer on the A surface is in the range of 500 to 600 nm, and either the B surface or the C surface is used. The minimum reflectance wavelength of at least one of the antireflection layers is 50 to 150 nm shorter than the minimum reflectance wavelength of the antireflection layer on the A plane. Since the minimum reflectance wavelength of the antireflection layer on the B surface or the C surface is 50 to 150 nm shorter than the minimum reflectance wavelength of the A surface, reflection can be reduced without causing strong blue or purple in the reflected light. . When the minimum reflectance wavelength of the A surface is close to the minimum reflectance wavelength of the B surface or C surface, the short wavelength and long wavelength intensities of visible light are relatively higher than the minimum reflectance wavelength. Even with a visible light reflectivity, it is easily colored and visible to the human eye. The minimum reflectance wavelengths of the antireflection layer on the B surface and the antireflection layer on the C surface may be substantially the same, but preferably the minimum reflectance wavelengths of the A surface, the B surface, and the C surface are shifted by 50 to 150 nm, respectively. It is a preferred embodiment. As the magnitude relationship, any of C <B <A, B <C <A, C <A <B, and B <A <C is preferably used.

The antireflection layers on the B and C surfaces preferably have an average visible light reflectance of 2% or less and a minimum reflectance of 1% or less, and particularly a minimum reflectance of 0.5% or less. This is a preferred embodiment. If the average visible light reflectance is low, the reflectance in the entire visible light range is low, the antireflection performance is high, and since it is not biased, it becomes a reflection color close to a natural color. Further, the minimum reflectance is 1% or less, and the minimum reflectance wavelength is 50 to 150 nm different from the antireflection film on the B surface or the C surface compared to the antireflection film on the A surface. There is no color bias due to action, and it exhibits reflective performance.
Unlike the A surface, the mechanical strength and antifouling properties of the antireflection layers on the B surface and the C surface may be less than those of the A surface. Therefore, it is preferable to use a simple structure of transparent substrate / low refractive index layer as the layer structure. Although it may have the same layer structure as the antireflection layer on the A surface, a simple layer structure can greatly improve the production efficiency. When the layer structure of transparent substrate / hard coat / low refractive index layer is used as the layer structure, the thickness of the hard coat layer can be 2 μm or less, preferably 0.2 μm to 1.5 μm. . As the hard coat layer, the same layer as the A-side antireflection layer can be used. Moreover, as a transparent base material, the thing similar to the antireflection layer of A surface can be used.

As the low refractive index layer of the antireflection layer on the B surface and the C surface, it can be easily used even if the mechanical strength is low. Therefore, the low refractive index layer may not be dense and may be porous. . For the low refractive index layer, the same material as that of the low refractive index layer of the antireflection layer on the A surface can be used. A refractive index having the same range as that of the A-plane can be used.
As an antireflection layer for the B and C surfaces, a pencil strength of 6B to 4H may be used. Further, a surface resistivity of 10 ¹⁶ Ω / □ or more can also be used. Care must be taken to prevent dust adhesion and damage when assembling the plasma display device. However, once assembled, no physical external force is applied to the B and C surfaces, so a simple structure is adopted. Also good.

On the other hand, since the antireflection layer disposed on the C surface is close to the plasma emission region, it is preferable to use a layer having a Tg of 80 ° C. or higher when an adhesive is used for placement. Moreover, what contains a UV absorber in an adhesive or a transparent base material is used preferably from a durable viewpoint.
When attaching the antireflection layer to the optical filter or front glass, install a highly transparent acrylic, silicone or rubber adhesive on the transparent substrate surface different from the surface on which the low refractive index layer is formed. It is attached by methods such as roll laminating and pressing.
Hereinafter, examples will be described in order to further clarify the present invention.

[Various measurement methods]
(1) Measurement of reflectance of antireflection layer: Acrylic optical adhesive is applied to a glass plate, and the transparent base side of the antireflection layer is pasted, and the reflected light on the back surface of the glass plate (the surface without the low refractive index layer). In order to cut, the back surface was roughed with sandpaper and then painted with black ink. Then, using a spectrophotometer UV-2450 / MPC2200 type 5 ° absolute reflectance measuring device (manufactured by Shimadzu Corporation), the reflectance spectrum in the wavelength range of 300 nm to 800 nm was measured at intervals of 0.5 nm.
The lowest reflectance here was defined as the minimum reflectance, and the wavelength at that time was defined as the minimum reflectance wavelength. The average value of the reflectance at a wavelength of λ400 to 700 nm was used as the average visible light reflectance.
(2) Refractive index estimation method: Samples are coated on a known sheet in various thicknesses, and the reflectance of 300 nm to 800 nm is measured using an FE3000 reflection spectrometer (manufactured by Otsuka Electronics Co., Ltd.). The refractive index of the sample was estimated by simulation, which is software attached to FE3000.
(3) Measurement of surface resistivity; Super insulation meter SM-8210 manufactured by Toa DKK Corporation as a measuring device, and electrode SME-8311 for flat plate samples as electrodes, and the surface resistivity was measured by a method prescribed in JIS K6911. . (20 ° C, 65RH%)
(4) The pencil hardness was evaluated at a load of 500 g according to the pencil hardness evaluation method defined in JIS K5400, using a test pencil defined in JIS S6006.
(5) Evaluation of visibility: Characters were displayed by digital signals on the plasma display device. A fluorescent lamp FPL27EX-N (manufactured by National) was installed as a light source at a position 1 m away from the surface to obtain an external light reflection model. Visual observation was performed at an angle of 0 to 20 ° from a position 1 m away from the plasma display device, and the visibility of the output character display and the reflected light of the reflected fluorescent lamp were evaluated.
The evaluation was made as a visual sensory evaluation in comparison with the plasma display device used as a blank. For the rank, a blank equivalent to Δ was evaluated, a better one was evaluated as “◯”, a lower one was evaluated as “×”, and a lower one was evaluated as “×”.

(Antireflection layer 1)
As a transparent substrate, a TAC film (thickness 80 μm) TDY80UL containing a UV absorber manufactured by Fuji Photo Film Co., Ltd. was used. Using KD200M manufactured by Nippon Kayaku Co., Ltd. as a hard coat, it was coated and cured (using a high-pressure mercury lamp) to a thickness of 1.5 μm on the TAC film. As a low refractive index layer, TU2085 (refractive index 1.40) manufactured by JSR Co., Ltd. and hollow silica fine particles (average diameter 60 nm, outer shell thickness of about 7 nm, refractive index 1.25) manufactured by Catalytic Chemical Co., Ltd. are used as a binder. The antireflection layer 1 was obtained by coating and curing (using Fusion UV) a layer having a thickness of .32 and a thickness of 100 to 110 nm. When the low refractive index layer was observed with a transmission electron microscope, the layer had a dense structure.
When the obtained antireflection layer was attached to glass using an adhesive LS0280 manufactured by Lintec Corporation, and the back surface treatment was performed to measure the reflectance, the wavelength of the minimum reflectance was 530 to 540 nm, and the minimum reflectance was 0.00. The average reflectance of visible light was 5% and 0.8%.

(Antireflection layer 2)
As a transparent substrate, a TAC film (thickness 80 μm) TDY80UL containing a UV absorber manufactured by Fuji Photo Film Co., Ltd. was used. A hard coat layer is not provided, and as a low refractive index layer, TU2085 (refractive index: 1.40) manufactured by JSR Co., Ltd., hollow silica fine particles (average diameter 60 nm, outer shell thickness of about 7 nm, refractive index 1.25) manufactured by Catalytic Chemical Co., Ltd. The layer having a refractive index of 1.29 and a thickness of 90 to 100 nm was applied and cured (using Fusion UV) to obtain the antireflection layer 2. When the low refractive index layer was observed with a transmission electron microscope, it was found that the layer was not dense and there was a gap between the hollow silica fine particles.
When the obtained antireflection layer was attached to glass using an adhesive LS0280 manufactured by Lintec Co., Ltd., and the back surface treatment was performed to measure the reflectance, the wavelength of the minimum reflectance was 455 to 465 nm, and the minimum reflectance was 0.00. The visible light average reflectance was 3% and 3%.

(Antireflection layer 3)
As a transparent substrate, a TAC film (thickness 80 μm) TDY80UL containing a UV absorber manufactured by Fuji Photo Film Co., Ltd. was used. A hard coat layer is not provided, and as a low refractive index layer, TU2085 (refractive index: 1.40) manufactured by JSR Co., Ltd., hollow silica fine particles (average diameter 60 nm, outer shell thickness of about 7 nm, refractive index 1.25) manufactured by Catalytic Chemical Co., Ltd. ) Was used to coat and cure a layer having a refractive index of 1.29 and a thickness of 115 to 125 nm (using Fusion UV) to obtain an antireflection layer 3. When the low refractive index layer was observed with a transmission electron microscope, it was found that the layer was not dense and there was a gap between the hollow silica fine particles.
When the obtained antireflection layer was attached to glass using a pressure-sensitive adhesive LS0280 manufactured by Lintec Corporation, and the back surface treatment was performed to measure the reflectance, the wavelength of the minimum reflectance was 615 to 625 nm, and the minimum reflectance was 0.00. The visible light average reflectance was 3% and 0.8%.

[Example 1]
Using a plasma display display device in which an optical filter is installed through an air layer, the antireflection film 1 is neatly installed on the surface layer of the optical filter with Lintech Corporation LSO280 acrylic adhesive (A-side antireflection layer) . Next, the antireflection layer 2 was placed on the back surface of the optical filter with an LSO280 adhesive (B surface antireflection layer). Further, the antireflection layer 3 was placed on the front glass of the plasma display with an LSO280 adhesive (C-side antireflection layer). Visibility was evaluated for those provided with these three antireflection layers. The results are summarized in Table 1.

[Example 2]
The same treatment as in Example 1 was performed except that the antireflection layer 2 was installed on the front glass surface of the plasma display device (C surface antireflection layer). The visibility of this product was evaluated, and the results are summarized in Table 1.
[Example 3]
The same treatment as in Example 1 was performed except that the antireflection layer was not provided on the front glass surface (C surface) of the plasma display device. The visibility of this product was evaluated, and the results are summarized in Table 1.
[Example 4]
The same treatment as in Example 1 was performed, except that the antireflection layer 1 placed on the front glass surface of the plasma display device was changed to the antireflection layer 1. The visibility of this product was evaluated, and the results are summarized in Table 1.

[Comparative Example 1]
Visibility of the plasma display device itself used in Example 1 was evaluated. The results are summarized in Table 1.
[Comparative Example 2]
The antireflection layer 1 was neatly placed on the optical filter of the plasma display device used in Example 1 by using Lintec Corporation LSO280 acrylic adhesive (A-side antireflection layer). Subsequently, the antireflection layer 1 was installed on the back surface of the optical filter with an LSO280 adhesive (B surface antireflection layer). Visibility was evaluated about what installed this antireflection layer. The results are summarized in Table 1.
[Comparative Example 3]
The antireflection layer 1 was placed on the front glass of the plasma display display device with LSO280 adhesive (C surface antireflection layer). About A side and B side, it carried out similarly to the comparative example 2. Visibility was evaluated about what installed this antireflection layer. The results are summarized in Table 1.

Plasma display device of the present invention, the reflection at the air layer interface is reduced, it is maintained naturally reflected color, image viewing is Ru facilitates der.

It is a schematic view illustrating a plasma di scan play display device of the present invention.

Explanation of symbols

1: Antireflection layer (A surface)
2: Optical filter 3: Antireflection layer (B side)
4: Antireflection layer (C surface)
5: Front glass 6: Plasma emission region 7: Rear glass 8: Plasma display panel (PDP)

Claims (3)

A plasma display device in which an antireflection layer is disposed on the A and B planes when the viewer side of the optical filter installed on the plasma display via an air layer is the A plane and the light emission side on the back side is the B plane. The minimum reflectance of the antireflection layer on the A surface is 0.5% or less, the minimum reflectance wavelength is in the range of 520 to 580 nm , and the minimum reflectance wavelength of the antireflection layer on the B surface is A surface. A plasma display device characterized by being 50 to 150 nm shorter than the minimum reflectance wavelength of the antireflection layer. When the observer side of the optical filter installed on the plasma display through the air layer is the A surface, the light emission side of the back side is the B surface, and the front glass surface facing the air layer is the C surface, the A surface and the B surface A plasma display device in which an antireflection layer is disposed on the C surface, wherein the A layer antireflection layer has a minimum reflectance of 0.5% or less and a minimum reflectance wavelength in the range of 520 to 580 nm. A plasma display device, wherein the minimum reflectance wavelength of at least one of the antireflection layers of the B surface and the C surface is 50 to 150 nm shorter than the minimum reflectance wavelength of the antireflection layer on the A surface. The average value of the reflectance at a wavelength of 400 to 700 nm of the antireflection layer disposed on the A surface is 2% or less, and the minimum reflectance in the wavelength range of 300 nm to 800 nm is 1% or less. 3. The plasma display device according to 2.

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