KR20060058559A - Method for preparing high resonance optical filter for image display devices and optical filter prepared by the same - Google Patents

Abstract

The present invention provides a photocatalyst film by coating a photocatalytic compound on a transparent substrate, selectively exposing the photocatalyst film, forming a metal nucleus, and then treating ethylenediamine (EDA) to selectively remove metal ions to form a metal pattern. The present invention relates to a method for manufacturing an optical filter for an image display device by accurately controlling the line width, and according to the method of the present invention, high transmittance, high resolution, and low resistivity characteristics can be achieved by a simple, low-cost process. The optical filter which has can be manufactured.

Metal pattern, photocatalyst, plating method, metal crystal growth, ethylenediamine (EDA), line width control, metal ion

Description

A manufacturing method of an optical filter for a high-resolution image display device and an optical filter manufactured thereby TECHNICAL FIELD             

1 is a process schematic diagram of a manufacturing method of an optical filter for an image display device according to an embodiment of the method of the present invention;

2a and 2b are electron micrographs comparing the metal pattern before and after the EDA treatment,

3 is an electron micrograph observing the change in line width according to the EDA treatment in the present invention.

The present invention relates to a method for manufacturing an optical filter for a high resolution image display device and an optical filter manufactured thereby, and more particularly, to selectively expose a photocatalyst film on a transparent substrate, and then to treat an ethylenediamine compound to selectively treat metal ions. The present invention relates to a manufacturing method of an optical filter for an image display device, and an optical filter manufactured thereby, wherein the resolution is improved by removing the resolution.

Many kinds of image display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), electroluminescent displays (ELDs), electroluminescent displays, and the like are commercially available. Among these various image display devices, plasma display panels are in the spotlight as large wall-mounted televisions and large screen displays for multimedia. Plasma display panel (PDP) encapsulates and seals an inert gas such as helium, neon, argon, xenon, etc. in a partition wall, and applies a high voltage to ionize the gas to form a plasma, and the ultraviolet rays emitted from the phosphor excite the phosphor. To emit light. PDP generates strong near-infrared rays that can cause malfunctions of cordless phones and remote controls, strong electromagnetic waves that adversely affect the human body and other electronic devices, and neon light that degrades color reproducibility. Required. Therefore, the PDP is equipped with a front filter capable of shielding such near-infrared and unnecessary electromagnetic waves and at the same time reducing the reflected light caused by external illumination.

Japanese Patent Laid-Open No. 10-278800 discloses a method of forming a transparent electrode on a display surface of a screen by sputtering, vapor deposition, or the like. However, such a method has a problem in that the transmittance is very low in order to have a sufficient electromagnetic shielding effect, and when the permeability is increased, the vehicle shielding performance is deteriorated. In other words, the film thickness in the range of 100 kPa to 2,000 kPa is necessary to secure the transmittance of visible light emitted from the PDP device, but there is a problem that a sufficient electromagnetic shielding effect cannot be obtained at such a film thickness.                         

Japanese Patent Laid-Open No. 2003-109435 constitutes a transparent conductive film composed of a metal ultrafine catalyst layer formed in a predetermined pattern on the transparent gas surface and a metal layer formed on the metal ultrafine catalyst layer, and contains an electroless plating catalyst on the transparent gas surface. A method of manufacturing a transparent conductive film in which a pattern is printed with a paste, an electroplating process is performed on the pattern printed electroless plating catalyst, and a transparent conductive metal layer is formed only by the pattern printing portion is disclosed. Such a method has the advantage of being easy to manufacture without requiring complicated processes such as a photoresist process and an etching process, but has a limitation that the resolution as an optical filter is insufficient and the yield is not suitable for mass production.

As another example, Japanese Patent Laid-Open Nos. Hei 5-16281 and Japanese Patent Laid-Open No. Hei 10-72676 form a transparent resin layer on a transparent substrate, such as polycarbonate, and after the electroless copper plating treatment thereon, etching by microphotographic etching process. The manufacturing method of the electromagnetic wave shielding filter material which forms a mesh pattern by the method is disclosed. However, this method is advantageous in terms of processing a metal thin film, but there is a problem in that the composition, temperature, and time of the etching solution are not easily managed during etching by a photolithography process.

As described above, most conventional technologies form a mesh pattern by a metal thin film process or a fine shape exposure process and a subsequent etching process, which mainly require high vacuum / high temperature, so that the overall process becomes complicated and the process cost increases. There is this. On the other hand, the manufacturing method that does not go through the metal thin film process and the etching process is advantageous in terms of price but can not obtain a sufficient resolution and light transmittance required for the optical filter and has a problem that the yield is not suitable for mass production.                         

Applicant in Korea Patent Application No. 2003-30110, the photocatalyst compound is coated on the substrate, and selectively exposed to form a potential pattern of the nuclei for crystal growth through photoreaction, and then plated it to the metal crystal A method of growing a metal pattern has been proposed. Specifically, when a metal nucleus is formed after selective exposure to a photocatalyst-coated substrate through a photomask, theoretically, only metal (eg, Pd ⁽⁰⁾ ) should be adsorbed to the light irradiation area, Adsorption of metal (eg, Pd ²⁺ ) ions occurs simultaneously by light bleeding or heat. In addition to metals, the form of metal ions can also act as nuclei for plating in the next step, resulting in increased line width. In such a case, it is difficult to accurately control the line width, which may cause a problem that the resolution of the optical filter is degraded.

The present invention is to compensate for the above-mentioned weaknesses in the prior art, and an object of the present invention is to improve the resolution by precisely controlling the line width by selectively removing only the metal ions through the treatment of ethylenediamine compound which is well chelated with metal ions. It is to provide a method for manufacturing an optical filter for an image display device.

One aspect of the present invention for achieving the above object is                     

Coating a photocatalytic compound on a transparent substrate to form a photocatalyst film;

Selectively exposing the photocatalyst film and then forming a metal nucleus by metal activation;

A third step of removing the metal in the ionic state by treating the ethylenediamine compound;

And a fourth step of obtaining a metal pattern by growing a metal crystal on the metal pattern by a plating method.

Another aspect of the invention features an optical filter made by the method of the invention.

Another aspect of the invention features a flat panel display element comprising an optical filter made by the method of the invention.

Hereinafter, with reference to the accompanying drawings will be described in more detail with respect to the present invention.

Looking at the manufacturing method of the optical filter for an image display device according to the present invention, first, a photocatalyst compound is coated on a transparent substrate to form a photocatalyst film (first step). The photocatalyst film is then selectively exposed to form a metal nucleus by metal activation (eg Pd activation) (second step). The metal in the ionic state is removed by the ethylenediamine compound treatment (third step), and metal crystals are grown on the metal pattern by plating to obtain a metal pattern (fourth step). Hereinafter, the steps will be described in more detail.                     

1. First step: photocatalyst film forming step

1 is a process schematic diagram illustrating a method of manufacturing an optical filter of an image display device according to an embodiment of the present invention. Referring to FIG. 1, first, a photocatalyst compound is coated on a transparent substrate to form a photocatalyst film.

There is no particular limitation on the transparent substrate usable in the present invention, but preferably, a transparent plastic substrate or a glass substrate can be used. Examples of the transparent plastic substrate may be acrylic resin, polyester, polycarbonate, polyethylene, polyethersulfone, olefinmaleimide copolymer, norbornene-based resin, and the like. When heat resistance is required, an olefin maleimide copolymer or norbornene-type resin is preferable, and when it is not, a polyester film, an acrylic resin, etc. can be used.

The "photocatalytic compound" used in the present invention is a compound whose properties are remarkably changed by light, and is a compound that is activated and becomes reactive when irradiated with light such as inactive or ultraviolet light before exposure. Such a photocatalytic compound is preferably a compound in which an inactive photocatalytic compound has an electron excitation due to a photoreaction to have a reducing ability, and more preferably, TiO _x (where x is 0, 1 or 2 after coating and heat treatment). It is an organic compound containing Ti which can form). Specific examples of Ti-containing organometallic compounds include tetraisopropyl titanate, tetra-n-butyl titanate, tetrakis (2-ethyl-hexyl) titanate (2-ethyl-hexyl) titanate), and polybutyl titanate, but are not necessarily limited to these.

In the present invention, the coating thickness of the Ti-containing organic compound layer is preferably 30 nm to 1000 nm, and after coating, the transparent Ti- is heated by heating in a hot plate or a microwave oven at a temperature of 200 ° C. or less for 20 minutes or less. A containing organic compound layer is formed. Heating at a temperature of 200 ° C. or more may cause a crystalline TiO ₂ layer to deteriorate the optical properties of the optical filter.

Subsequently, the water-soluble polymer layer may be formed on the Ti-containing organic compound layer formed as described above to form a water-soluble polymer layer. The water-soluble polymer layer serves to enhance photocatalytic activity by promoting photoreduction during subsequent UV exposure. do. Examples of water-soluble polymers usable in the present invention include, but are not necessarily limited to, homopolymers or copolymers such as polyvinyl alcohol, polyvinylphenol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, gelatin, and the like. . A water-soluble polymer is dissolved in water at a concentration of 30% or less, coated on the Ti-containing organic compound layer, and heated to form a final photocatalyst film.

In order to activate the photosensitivity during formation of the water-soluble polymer layer, a photosensitizer compound may be added to the aqueous solution of the water-soluble polymer. Examples of photosensitizer compounds usable in the present invention include water soluble pigments, organic acids, organic acid salts, organic ethylenediamine, and the like. Specific examples include tar pigments, potassium or sodium salts of chlorophyllin, riboflavin and derivatives thereof, water soluble annatoto, CuSO ₄ , caramel, curcumine, cochinal, citric acid, ammonium citrate And compounds such as sodium citrate, oxalic acid, potassium tartarate, sodium tartarate, ascorbic acid, formic acid, triethanol ethylenediamine, monoethanol ethylenediamine, malic acid and the like. The water-soluble polymer layer is used after the coating method by heating at a temperature of 80 ℃ or less after 5 minutes to dry the moisture, and the thickness of the water-soluble polymer layer is preferably adjusted to 1 ㎛ or less.

2. Formation of Potential Patterns of Nuclear Crystal

The photocatalyst film obtained in the first step is selectively exposed to UV light using a photo mask or the like to obtain a potential pattern of crystal growth nuclei consisting of an activated portion and an inactivated portion. At the time of exposure, exposure conditions, such as an exposure atmosphere or an exposure amount, are not specifically limited, It can select suitably according to the kind of photocatalyst compound to be used.

When the photocatalyst film is exposed, as described above, electron excitation occurs in the exposed portion, and the compound exhibits activity such as reduction characteristics, thereby reducing metal ions.

After exposure of the photocatalyst film to obtain a potential pattern of nuclei for crystal growth, if necessary, the pattern is immersed in a suitable metal salt in order to more effectively form a metal pattern to obtain a pattern in which metal particles in the metal salt are deposited. The water soluble high molecular layer can be completely removed. The deposited metal particles (metal nuclei) serve as catalysts for promoting metal crystal growth in subsequent plating processes. For example, in the case of copper, nickel, or gold plating treatment, it is preferable to perform such metal salt treatment. Preferably, as the metal salt solution for this purpose, an Ag salt solution, a Pd salt solution or a mixed solution of Ag salt and Pd salt may be used.

3. Ethylenediamine Compound Treatment Step

In the present invention, in order to precisely control the line width of the metal pattern to improve the resolution of the optical filter, the metal pattern is treated with an ethylenediamine compound which is well chelated with metal ions (eg, Pd ²⁺ ions). Treatment of the latent pattern with ethylenediamine compounds in the present invention facilitates the removal of ethylenediamine and metal ions (eg, Pd ²⁺ ) because they form complexes and these complexes are well soluble in water.

In the case of treating the ethylenediamine compound according to the present invention, an aqueous solution is prepared by adding an ethylenediamine compound to deionized water, and then a metal pattern is put into the prepared aqueous solution of ethylenediamine compound and deposited for a predetermined time, and then taken out. In this invention, it is preferable that the density | concentration of the ethylenediamine aqueous solution is 0.2M-10.0M, and a processing time can be adjusted with the density | concentration etc. of ethylenediamine aqueous solution.

4. Metal pattern formation step

A potential pattern of crystal growth nuclei or a pattern in which metal particles are deposited on the potential pattern as necessary is plated to grow metal crystals to obtain a metal pattern. At this time, two or more kinds of metals may be grown by plating to obtain a multilayer metal pattern. Such plating treatment is performed by electroless plating or electroplating.

In the case of a pattern in which metal particles are deposited by treating with a metal salt solution, a pattern in which palladium or silver metal particles are deposited has a sufficient activity as a catalyst for an electroless plating solution, thereby promoting crystal growth by plating, and thus a metal having a finer structure It is more advantageous to obtain a pattern.

As a plating metal used for a plating process, Cu, Ni, Ag, Au, and these metal alloys can be suitably selected and used according to the use of a metal pattern. In order to obtain a highly conductive metal pattern, a copper metal compound solution or a silver metal compound solution is preferably used.

Electroless plating or electroplating may be carried out according to a known method, which will be described in more detail as follows:

When the electroless plating method is used as the copper metal crystal growth method, the crystals are coated in a plating solution containing 1) copper salt, 2) reducing agent, 3) complexing agent, 4) pH adjusting agent, 5) pH buffer, and 6) improving agent. The substrate having the growth nucleus pattern is plated by dipping.

1) The copper salt serves to supply copper ions to the substrate, and examples of the copper salt include chloride, nitrate, sulfate, and cyanide compounds of copper. Preferably copper sulfate is used.                     

2) The reducing agent serves to reduce metal ions on the substrate, specific examples of the reducing agent include a polysaccharide compound such as NaBH ₄ , KBH ₄ , NaH ₂ PO ₂ , hydrazine, formalin or glucose. Preferably a polysaccharide compound such as formalin or glucose is used.

3) The complexing agent prevents hydroxide precipitation in the alkaline solution and controls free metal ion concentration to prevent decomposition of metal salts and to control the plating rate. Specific examples of the complexing agent include ammonia solution and acetic acid. Chelating agents such as guanic acid, tartarate and EDTA, or organic amine compounds. Preferably, a chelating agent such as EDTA is used. 4) The pH adjusting agent serves to adjust the pH of the plating solution, and is an acid or a base compound. 5) pH buffering agent suppresses pH fluctuation of plating solution and contains various organic acid and weak acid inorganic compound. 6) Enhancer The compound refers to a compound capable of improving coating properties and planarization properties, and specific examples thereof include general surfactants and adsorbent materials capable of adsorbing components that interfere with crystal growth.

When the electroplating method is used by the copper metal crystal growth method, the pattern is immersed in a plating composition containing 1) copper salt, 2) complexing agent, 3) pH adjusting agent, 4) pH buffer, and 5) improving agent. . The role and specific examples of the components contained in the plating solution composition are as described above.

In the case of using the electroless plating method as the silver metal crystal growth method, the composition for plating comprising 1) silver salt, 2) reducing agent, 3) complexing agent, 4) pH adjusting agent, 5) pH buffer and 6) improving agent Immerse the pattern. Specific examples of the above 1) silver salt include chlorides of silver, nitrates of silver and cyanates of silver, preferably silver nitrate compounds. The role and specific examples of other components contained in the plating solution composition are as described above.

When the electroplating method is used as a silver metal crystal growth method, the pattern is immersed in a plating composition comprising 1) silver salt, 2) complexing agent, 3) pH adjusting agent, 4) pH buffer and 5) improving agent. The role and specific examples of the components contained in the plating solution composition are as described above.

The optical filter for an image display device manufactured by the method of the present invention has a high resolution because the line width of the metal pattern is within 10 m. The optical filter according to the present invention may be provided with an antireflection film having antireflection ability against visible light.

The optical filter of the present invention can be used in various image display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescent display (ELD), and especially for plasma display panel (PDP) and its front panel. In this case, it may provide an advantageous effect.

Example

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the following examples are only intended to illustrate preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the following examples.

Example 1

An isopropanol solution (2.5 wt.%) Of polybutyl titanate was applied onto the transparent glass substrate by spin coating and dried at 100 ° C. for 5 minutes to form an amorphous TiO ₂ film. The TiO ₂ film thickness obtained at this time was adjusted to about 30 to 100 nm. Then a molecular weight of 6,000 to 25,000 poly aqueous solution of the vinyl alcohol polymer (5% by weight) was stirred by the addition of triethanolamine 1 wt% of zero photosensitizer for the high molecular weight and coated on the above-described TiO ₂ coating film for 3 minutes in 100 ℃ Dried. Subsequently, UV rays of a wide wavelength range were irradiated onto the substrate through a photomask in which a fine mesh pattern was formed using UV exposure equipment of Oriel, USA. After exposure, 0.3 g of PdCl ₂ and 1 ml of HCl were immersed in a solution prepared by dissolving in 1 L of water to allow Pd metal particles to be deposited on the surface of the exposed portion to obtain a negative pattern of crystal growth nuclei composed of Pd.

A 0.2 M aqueous solution was prepared by adding 6.01 g of ethylene diamine (EDA) to 500 ml of deionized water (ultra pure water). The sample was added to the prepared aqueous solution, and the sample was deposited for about 10 minutes and then taken out. At this time, the treatment temperature was room temperature and the pH was 5.07.

The ethylenediamine treated glass substrate was immersed in an electroless copper plating solution to selectively grow crystals of a metal pattern to form a copper mesh pattern having a thickness of 2 μm and a line width of 10 μm. At this time, the copper plating solution was prepared by mixing 3.5 g of copper sulfate, 8.5 g of lotel salt, 22 ml of formalin (37%), 1 g of thiourino, 40 g of ammonia, and 1 l of water. Electroless plating was performed for 5 minutes in the state which kept the temperature of copper plating liquid at 35 degreeC. The sheet resistance of the produced mesh pattern was 0.01 kPa / square or less. The line width and thickness of the metal pattern obtained in Example 1 were measured and the results are shown in Table 1 below.

Comparative Example 1

Except that the EDA treatment before the metal pattern was formed by the plating method was carried out in the same manner as in Example 1 to form a metal pattern and the line width and thickness were measured and the results are shown in Table 1 together.

 EDA processing Processing time (minutes) pH Solution temperature (℃) Settling time (seconds) Line width (㎛) Thickness Example 1 process 10 minutes 5.07 53.4 40 20 1800 Comparative Example 1 Untreated 0 - - 0 50 2000

2A and 2B are photographs taken by electron microscope of metal patterns formed by Comparative Examples 1 and 1, respectively. As shown in FIGS. 2A and 2B, in the case of the metal pattern formed by Comparative Example 1 without undergoing EDA treatment (FIG. 2A), the line width is about 50 μm, whereas in Example 1 obtained by the method of the present invention. It can be seen that the metal pattern (FIG. 2B) can provide high resolution with a line width of 20 μm or less.

3 is a result of observing a change in line width according to the EDA treatment time. As observed through FIG. 3, the line width change with the ethylenediamine compound treatment time is not large (8 micrometers → 6 micrometers). As the EDA treatment time increases, the shadow portion (shadow portion formed by metal plating in the area other than the light irradiation area) gradually decreases (20 μm → 12 μm), and when the EDA treatment time is 6 minutes or more, the mesh is locally Not formed.

According to the method of the present invention, an optical filter for an image display device can be obtained efficiently and at low cost in a short time without using a sputtering step requiring a high vacuum / high temperature condition, a photo patterning step using a photosensitive resin, and an etching step. In addition, the optical filter manufactured by the method of the present invention has the advantage that the line width of the metal pattern is precisely controlled and the resolution is excellent.

Claims (15)

Coating a photocatalytic compound on a transparent substrate to form a photocatalyst film; A second step of forming a metal nucleus after selectively exposing the photocatalyst film; A third step of removing the ionic metal by ethylenediamine treatment; And a fourth step of obtaining a metal pattern by growing a metal crystal on the metal pattern by a plating method. The method of manufacturing an optical filter for a high resolution image display device according to claim 1, wherein the ethylenediamine treatment step is a process of taking out a potential metal pattern in an aqueous solution of ethylenediamine compound for a predetermined time and then taking it out. The method of manufacturing an optical filter for a high resolution image display device according to claim 2, wherein the concentration of the aqueous solution of ethylenediamine compound is 0.2M to 10.0M. The method of manufacturing an optical filter for a high resolution image display device according to claim 1, wherein the method further comprises laminating an antireflection film on the entire surface of the transparent substrate. The method of claim 1, wherein the transparent substrate is a glass substrate or an acrylic resin, polyester, polycarbonate, polyethylene, polyethersulfone, olefin maleimide copolymer, nor is a transparent plastic substrate selected from the group consisting of norbornene-based resin A method of manufacturing an optical filter for a high resolution image display device. A method of manufacturing an optical filter for a high resolution image display device according to claim 1, wherein a Ti-containing organic compound is used as the first photocatalyst compound. 7. The method of claim 6, wherein the first step comprises forming a photosensitizer-containing water-soluble polymer layer on the Ti-containing organic compound layer. 8. The method of claim 7, wherein the water-soluble polymer layer is composed of a material selected from the group consisting of polyvinyl alcohol, polyvinylphenol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, gelatin homopolymer or copolymer. A method of manufacturing an optical filter for a high resolution image display device, characterized in that. The method of claim 7, wherein the photosensitizer is a tar pigment, a potassium or sodium salt of chlorophyllin, riboflavin and its derivatives, water soluble annatoto, CuSO ₄ , caramel, curcumine, kochinal ( cochinal), citric acid, ammonium citrate, sodium citrate, oxalic acid, potassium tartarate, sodium tartarate, ascorbic acid, formic acid, triethanolamine, monoethanolamine, malic acid, at least one selected from the group consisting of Method for producing optical filter for use. The method of claim 1, wherein the method further comprises treating the potential pattern of the crystal growth nucleus of the second step with a metal salt solution to deposit metal particles in the metal salt solution and completely remove the water-soluble polymer layer in the pattern. The manufacturing method of the optical filter for high resolution image display apparatuses characterized by the above-mentioned. The method of manufacturing an optical filter for a high resolution image display device according to claim 10, wherein the metal salt solution is an Ag salt solution, a Pd salt solution or a mixed solution of Ag salt and Pd salt. The method of manufacturing an optical filter for a high resolution image display device according to claim 1, wherein said fourth step is a step of obtaining at least two kinds of metals by plating to obtain a metal pattern. The method of claim 1, wherein the plating process of the fourth step is performed by an electroless plating method or an electrolytic plating method, and the plating metal is selected from the group consisting of Ni, Cu, Ag, Au or alloys thereof. A manufacturing method of an optical filter for a high resolution image display device. An optical filter for a high resolution image display device manufactured by the method of claim 1. An image display device comprising the optical filter of claim 14.

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