Optical filter for image display devices and manufacturing method thereof

Abstract

An optical filter that may include a transparent substrate, a photocatalytic film formed on the back surface of the transparent substrate, a metal pattern formed by selectively exposing the photocatalytic film to light and growing a metal crystal thereon by plating, and a near-infrared ray shielding and photoselective absorbing layer formed on the metal pattern. Since the optical filter may exhibit superior color reproduction and excellent shielding performance against electromagnetic waves, near-infrared rays and neon light, it may be applied to a variety of image display devices, e.g., PDPs.

1 . An optical filter for image display devices, comprising: 
 a transparent substrate;    a photocatalytic film formed on a back surface of the transparent substrate;    a metal pattern formed by selectively exposing the photocatalytic film to light and growing a metal crystal thereon by plating; and    a near-infrared ray shielding and photoselective absorbing layer formed on the metal pattern.    
     
     
         2 . The optical filter according to  claim 1 , further comprising an antireflective film formed on a front surface of the transparent substrate.  
     
     
         3 . The optical filter according to  claim 1 , wherein the near-infrared ray shielding and photoselective absorbing layer comprises: 
 at least one near-infrared ray absorbing material selected from the group consisting of mixed dyes of a nickel complex and a diammonium, compound dyes containing copper ions and zinc ions, cyanine dyes, anthraquinone dyes, squarylium compounds, azomethine compounds, oxonol compounds, azo compounds, and benzylidene compounds; and    at least one neon light blocking material selected from the group consisting of octaphenyltetraazaporphyrin and tetraazaporphyrin derivative dyes in which one ligand selected from ammonia, water and halogen is coordinately bonded to a central metal (M) atom of an octaphenyltetraazaporphyrin or tetraazaporphyrin ring.    
     
     
         4 . The optical filter according to  claim 1 , wherein the near-infrared ray shielding and photoselective absorbing layer has a thickness of 1-20 μm.  
     
     
         5 . The optical filter according to  claim 1  wherein the transparent substrate is a glass substrate or a transparent plastic substrate selected from the group consisting of acrylic resins, polyesters, polycarbonates, polyethylenes, polyethersulfones, olefin-maleimide copolymers, and norbornene-based resins.  
     
     
         6 . The optical filter according to  claim 2 , wherein the near-infrared ray shielding and photoselective absorbing layer comprises: 
 at least one near-infrared ray absorbing material selected from the group consisting of mixed dyes of a nickel complex and a diammonium, compound dyes containing copper ions and zinc ions, cyanine dyes, anthraquinone dyes, squarylium compounds, azomethine compounds, oxonol compounds, azo compounds, and benzylidene compounds; and    at least one neon light blocking material selected from the group consisting of octaphenyltetraazaporphyrin and tetraazaporphyrin derivative dyes in which one ligand selected from ammonia, water and halogen is coordinately bonded to a central metal (M) atom of an octaphenyltetraazaporphyrin or tetraazaporphyrin ring.    
     
     
         7 . The optical filter according to  claim 2 , wherein the near-infrared ray shielding and photoselective absorbing layer has a thickness of 1-20 μm.  
     
     
         8 . The optical filter according to  claim 2  wherein the transparent substrate is a glass substrate or a transparent plastic substrate selected from the group consisting of acrylic resins, polyesters, polycarbonates, polyethylenes, polyethersulfones, olefin-maleimide copolymers, and norbornene-based resins.  
     
     
         9 . The optical filter according to  claim 2 , wherein the antireflective film comprises at least one material selected from the group consisting of silicon-based organic materials, fluorine-based organic materials, indium tin oxide (ITO), ZnO, Al-doped ZnO, TiO 2 , and ZrO.  
     
     
         10 . A method for manufacturing an optical filter for image display devices, comprising the steps of: 
 coating a photocatalytic compound on a back surface of a transparent substrate to form a photocatalytic film (a first step);    selectively exposing the photocatalytic compound to light and growing a metal crystal thereon by plating to form a metal pattern (a second step); and    coating a resin containing a near-infrared ray shielding material and a photoselective absorbing material on the metal pattern to form a near-infrared ray shielding and photoselective absorbing layer (a third step).    
     
     
         11 . The method according to  claim 10 , further comprising the step of laminating an antireflective film on a front surface of the transparent substrate.  
     
     
         12 . The method according to  claim 10 , wherein the first step includes the sub-steps of: 
 coating a Ti-containing organic compound as the photocatalytic compound on the transparent substrate to form a Ti-containing organic compound layer; and    forming a photosensitizer-containing water-soluble polymer layer on the Ti-containing organic compound layer.    
     
     
         13 . The method according to  claim 10 , wherein the metal pattern is formed by growing two or more metals by plating in the second step.  
     
     
         14 . The method according to  claim 10 , wherein the coating step comprises preparing a coating solution, wherein the coating solution is prepared by mixing a near-infrared ray absorbing material, a photoselective absorbing material and a binder resin in an organic solvent; 
 the near-infrared ray absorbing material being at least one material selected from the group consisting of mixed dyes of a nickel complex and a diammonium, compound dyes containing copper ions and zinc ions, cyanine dyes, anthraquinone dyes, squarylium compounds, azomethine compounds, oxonol compounds, azo compounds, and benzylidene compounds; and    the photoselective absorbing material being at least one materail being selected from the group consisting of octaphenyltetraazaporphyrin and tetraazaporphyrin derivative dyes in which one ligand selected from ammonia, water and halogen is coordinately bonded to a central metal (M) atom of an octaphenyltetraazaporphyrin or tetraazaporphyrin ring.    
     
     
         15 . The method according to  claim 14 , wherein the near-infrared ray absorbing material is used in an amount of 0.1 to 1 part by weight, based on 100 parts by weight of the binder resin, and the photoselective absorbing material is used in an amount of 0.1 to 1 part by weight, based on 100 parts by weight of the binder resin.  
     
     
         16 . The method according to  claim 14 , wherein the binder resin is selected from the group consisting of natural polymers, polymethylmethacrylate, polyvinylbutyral, polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl chloride, styrene-butadiene copolymer, polystyrene, polycarbonate, and water-soluble polyamide.  
     
     
         17 . The method according to  claim 14 , wherein the organic solvent is selected from the group consisting of toluene, xylene, propyl alcohol, isopropyl alcohol, methylcellosolve, ethylcellosolve, dimethylformamide, methyl ethyl ketone, and butylacetate.