KR20020010829A - Composition for filter layer and filter layer formed therefrom - Google Patents

Abstract

PURPOSE: Provided are a composition for forming a filter membrane and the filter membrane used for a cathode ray tube, which can improve contrast without reducing brightness by minimizing reflection in the outer or inner faces of a display panel. CONSTITUTION: The composition for forming the filter membrane comprises an oxide pigment impregnated with metal particles which resonance-absorbs selectively light with special wavelength, a dispersing agent such as polyvinyl pyrrolidone, and a solvent, wherein the oxide pigment impregnated with the metal particles is produced by forming precipitates of a composition comprising a salt containing the metal particles, a metal alkoxide for forming the oxide or a metal salt, a catalyst, and a solvent and then drying and heat-treating the composition. And the filter membrane is produced by coating and drying the composition for forming the filter membrane.

Description

Composition for filter layer and filter membrane formed therefrom {Composition for filter layer and filter layer formed therefrom}

The present invention relates to a composition for forming a filter film and a filter film formed therefrom. More particularly, the present invention relates to a filter film capable of improving contrast of an image display device using a surface plasma resonance (SPR) phenomenon. A composition for formation and a filter membrane formed using this composition.

In order to improve the contrast of the cathode ray tube, it is possible to minimize the reflection of the light of the external light source from the surface and the inner surface of the cathode ray tube panel, and to absorb a relatively large amount of side bands around 575 nm of the red phosphor. Coatings for this purpose have been concentrated mainly on the outer surface coating of the cathode ray tube. In such an outer coating, a method of forming a multilayer film mainly made of a transparent oxide material was used. In this method, a plurality of transparent oxide layers having different refractive indices are coated on the outer surface of the panel of the cathode ray tube and the thickness of the coating film is adjusted to reduce the external reflection by the optical interference phenomenon. As another method of outer coating, US Pat. Nos. 5,200,667, 5,315,209 and 5,218,268 disclose a method for forming a film layer on the panel outer surface of a cathode ray tube comprising a dye or pigment that absorbs light of a particular wavelength. .

However, the above methods attempt to improve contrast by reducing the reflection of the outer surface of the cathode ray tube, but there is a problem in that the reflection of light generated at the interface between the inner surface of the panel and the phosphor is not reduced.

In order to solve this problem, US Pat. Nos. 4,019,905, 4,132,919, and 5,627429 disclose a method for forming an intermediate layer containing a pigment capable of absorbing light in a specific wavelength band between an inner surface of a panel and a fluorescent film. US Patent Nos. 5,068,568 and 5,179,318 disclose a method of utilizing an optical interference phenomenon by alternately stacking a low refractive index layer and a high refractive index layer between an inner surface of a panel and a fluorescent film.

The technical problem to be achieved by the present invention is to reduce the reflection of the outer surface or the inner surface of the display panel more than the above-described methods, and to improve the contrast of the image display apparatus by absorbing relatively more overlapping wavelengths of the phosphor emission peaks. It is providing a composition for forming a filter film.

Another object of the present invention is to provide a filter film which can be formed from the composition for forming a filter film to minimize reflection on the outer and inner surfaces of a panel of an image display device, thereby improving contrast without decreasing luminance.

Another technical problem to be achieved by the present invention is to provide a cathode ray tube capable of minimizing reflection on the outer and inner surfaces of a panel by employing the filter membrane, thereby improving contrast without decreasing luminance.

1 is a view showing a form in which metal fine particles are impregnated with an oxide,

2 is a view showing a form in which the metal particles are adsorbed on the oxide surface,

3 is a view showing a form in which a part of the metal fine particles are impregnated in the oxide and a part of the remaining metal fine particles are adsorbed on the oxide surface,

Figure 4 is a view showing a form in which the oxide pigment impregnated or adsorbed nano-size metal particles in the filter membrane according to the present invention dispersed in the membrane.

<Explanation of symbols for the main parts of the drawings>

41 ... substrate 42 ... filter membrane

43. Oxide pigments impregnated or adsorbed with metal particulates

In order to achieve the first technical problem, the present invention includes an oxide pigment, a dispersant and a solvent impregnated or adsorbed with nano-sized metal particles selectively resonance-absorbing light of a specific wavelength range,

The metal fine particle impregnation or adsorption oxide pigment,

Metal fine particle-containing salt, oxide metal alkoxide (M (OR) n) (M is at least one selected from the group consisting of alkali metals, alkaline earth metals and transition metals, R is an alkyl group having 1 to 15 carbon atoms, n is 1 To 4) or a metal salt (MX) (M is at least one selected from the group consisting of alkali metals, alkaline earth metals and transition metals, X is nitrate, chloride or sulfonate), impregnated with metal particulates or catalysts or Provided is a composition for forming a filter film, which is obtained by forming a precipitate from an adsorbed oxide pigment composition and drying and heat treating the precipitate.

The second technical problem of the present invention is to form a dispersion, coating and drying of the composition, so that the metal particles impregnated or adsorbed oxide pigment particles selectively resonance-absorbing light of a specific wavelength band is dispersed by the filter membrane, characterized in that Is done.

A third technical problem of the present invention is achieved by an image display element, characterized in that a filter film is employed.

As a preferable surface of the said image display element, a cathode ray tube, a plasma display panel, a liquid crystal display, etc. are mentioned. The filter film of the cathode ray tube is formed between the panel and the fluorescent film or on a surface exposed to the outside of the panel, or a first filter film is formed between the inner surface of the panel and the fluorescent film and a second filter film is formed on the outer surface of the panel.

In the cathode ray tube, contrast decreases not only by the reflection on the outer surface of the panel but also by the reflection on the inner surface of the panel. Especially due to the scattering effect due to the phosphor particle size, the effect by internal reflection is relatively greater. In the present invention, in order to minimize this phenomenon, a filter film is formed on the inner surface of the panel, the outer surface of the panel, or both the inner surface and the outer surface of the panel, and the oxide pigment impregnated with or adsorbed metal fine particles is used to prepare the filter membrane. The oxide pigment absorbs light in a specific wavelength range, particularly in the 575 nm region, by resonance absorption of nanosized metal particles impregnated or adsorbed therein. Therefore, the filter membrane including the oxide pigment impregnated with or adsorbed by the metal fine particles can effectively absorb light in the 575 nm region by the pigment itself, and has a high color purity by absorbing in a single region as compared with the case of using a general pigment or dye. . In addition, oxide pigments impregnated or adsorbed with metal particles have an advantage of freely controlling the intensity and position of absorption peaks. The intensity of the absorption peak is influenced by the size or amount of the impregnated or adsorbed metal fine particles, and the position of the absorption peak changes depending on the refractive index of the oxide used as the matrix, the type and size distribution of the added metal.

In the case of using a metal fine particle-containing salt as a starting material and preparing a dielectric matrix coating liquid using a sol-gel, an absorption peak is usually exhibited at a specific wavelength in accordance with the type of the metal fine particles. For example, when the dielectric matrix is silica (SiO 2) (refractive index: 1.46) and the metal particles dispersed in the silica matrix in nano size are silver (Ag), gold (Au), and copper (Cu), the absorption peaks are 410 nm and 530 nm, respectively. , 580nm. At this time, in order to shift the absorption wavelength, a second phase matrix such as alumina (Al ₂ O ₃ ), titania (TiO ₂ ), zirconia (ZrO ₂ ), etc. having a high refractive index is added to the silica as the first phase matrix, and the absorption peak intensity is increased. Adjust the amount of metal salt to control. In addition, the heat treatment temperature after applying and drying the composition for forming the filter film is adjusted to be higher than the thermal decomposition temperature of the metal salt so that the metal salt can be reduced to the corresponding metal. For example, in the case of gold, the heat treatment temperature is adjusted to 200 ° C or higher, in the case of silver to 500 ° C or higher, and in the case of copper, to be 650 ° C or higher. Similarly, in the present invention, in the case of producing an oxide matrix pigment impregnated or adsorbed with metal fine particles, the absorption wavelength can be shifted to a longer wavelength by mixing silica, which is a first phase matrix, and a second phase matrix having a larger refractive index. The type and content of the metal fine particles to be impregnated can be adjusted to shift the position of the absorption wavelength and the intensity of the absorption peak. Since the metal fine particle impregnation or the adsorbed oxide pigment already absorbs light in a specific wavelength range, the filter membrane formed by dispersing and coating the same may obtain a desired absorption peak without additional heat treatment.

Looking at the representative method for forming the filter membrane according to the present invention by adjusting the position and intensity of the absorption peak by using the characteristics as described above are as follows. In this case, silica is used as the matrix and Au is used as the metal fine particles.

First, when silica is used as the matrix, its refractive index is 1.46 Therefore, the resonance absorption wavelength due to the particles of gold impregnated or adsorbed therein is about 530 nm. However, in order to use this pigment as it is, it is inappropriate because it does not match the wavelength range to absorb. Thus, in order to increase the refractive index of the matrix oxide, SiO₂Al₂O₃, TiO₂, ZrO₂Can be added to adjust the resonance absorption wavelength in the 575nm region.

Second, in order to shift the absorption wavelength region to 575 nm as a single phase, the content and particle diameter of gold impregnated or adsorbed in the oxide powder may be controlled.

Third, in the preparation of the metal fine particles impregnated or adsorbed oxide pigment, the heat treatment temperature should be equal to or higher than the reduction temperature of the impregnated metal salt and is treated at the crystallization temperature of the oxide or lower amorphous temperature. Since the refractive index of the oxide is different according to the heat treatment temperature even in the same composition, the position of the resonance absorption wavelength is changed accordingly, so that the heat treatment temperature is changed to obtain a desired wavelength.

Looking at the composition for forming a filter membrane of the present invention and the process for producing a filter membrane using the same in more detail as follows.

The composition for forming a filter film according to the present invention is prepared by adding a dispersant and a solvent to an oxide pigment impregnated or adsorbed with nano-sized metal particles selectively resonance-absorbing light of a specific wavelength band, and sufficiently mixing them. The filter membrane which concerns on this invention is completed by apply | coating and drying on the board | substrate to apply | coat the composition for filter film formation obtained in this way. At this time, the drying is carried out at 100 to 150 ℃, the filter membrane of the present invention does not undergo a separate heat treatment step. In addition, the content of the metal fine particles impregnated or adsorbed oxide pigment is preferably 1 to 5% by weight based on the total weight of the filter film-forming composition. If the content of the metal fine particles impregnated or adsorbed oxide pigment is more than 5% by weight, the absorption strength is large, so that the brightness is lowered. If the content is less than 1% by weight, the absorption strength is weak and the contrast enhancement effect is small, which is not preferable.

The dispersant constituting the composition for forming the filter film is a substance for preventing aggregation and precipitation of the oxide pigment impregnated or adsorbed in the organic solvent, and includes polyvinylpyrrolidone, polyvinyl alcohol, and hydroxy. Propyl cellulose and the like are used. The content of the dispersant is 5 to 15% by weight based on the total weight of the composition for forming a filter film. If the content of the dispersant is more than 15% by weight, the coating property is poor and the film is too thick. If the content of the dispersant is less than 5% by weight, the adhesion is poor and the film is too thin. As the organic solvent, any material capable of impregnating metal fine particles or dissolving an adsorbent oxide pigment and a stabilizer may be used. Specific examples thereof include methanol, ethanol, propanol, butanol, and a mixture thereof. The content of the solvent is 80 to 94% by weight based on the total weight of the composition for forming a filter film. If the content of the solvent exceeds 94% by weight, the absorption strength is weak and less than 80% by weight, it is not preferable because the absorption strength is strong and film formation is not good.

It is also possible to add a ball, such as zirconia beads, to paint shake in order to increase the mixing of the composition, and to further add a dispersant, a binder, and the like to increase the dispersibility in some cases.

The metal fine particle-impregnated or adsorbed oxide pigments constituting the composition for forming a filter film may include metal fine particle-containing salts, metal alkoxides for oxide formation (M (OR) n) (M is an alkali metal, an alkaline earth metal and a transition metal). At least one selected, R is an alkyl group having 1 to 15 carbon atoms, n is 1 to 4) or a metal salt (MX) (M is at least one selected from the group consisting of alkali metals, alkaline earth metals and transition metals), X is Obtained by forming a precipitate from the metal fine particle impregnation or adsorbent oxide pigment composition consisting of a latex, chloride or sulfonate), a catalyst and a solvent, and drying and heat-treating the precipitate.

In the preparation of the metal fine particle impregnation or the adsorbent oxide pigment, the catalyst is a material which functions to promote the hydrolysis reaction of the metal alkoxide, and uses ammonia water, sodium borohydride, sodium citrate, hydrazine hydrate, formamide and the like. The content of the catalyst here is suitably 1 to 10% by weight, based on the total weight of the metal particulate impregnation or adsorptive oxide pigment composition.

The drying temperature of the precipitate formed from the above-mentioned metal fine particle impregnation or adsorption oxide pigment composition is 120 to 150 ° C. If the drying temperature exceeds 150 ° C, the metal salt is reduced beforehand, and if it is less than 120 ° C, the precipitate is not dried. Not desirable The heat treatment temperature is 200 to 650 ℃ to adjust above the thermal decomposition temperature of the metal fine particles containing salt. In this heat treatment step, the metal fine particle-containing salt is reduced to the corresponding metal fine particles.

The metal fine particle-containing salt is a chloride (chloride), nitrate (nitrate) or sulfonate containing one or more metals selected from the group consisting of gold, silver, copper, platinum, nickel, cobalt, rhodium, rubidium, lead and palladium ( Sulfonate), and the content of the metal fine particle-containing salt is preferably 0.1 to 5% by weight based on the total weight of the metal fine particle impregnation or the adsorbing oxide pigment composition. If the content of the metal fine particle-containing salt is more than 5% by weight, the metal which is not impregnated or adsorbed is formed, and when it is less than 0.1% by weight, the absorption strength of the pigment is weakened.

In the metal alkoxide M is at least one selected from the group consisting of Si, Ti, Zr and Al, n is 1 to 4 and in the metal salt M is at least one selected from the group consisting of alkali metals, alkaline earth metals and transition metals , X is preferably nitrate, chloride or sulfonate. Specific examples of metal alkoxides include titanium tetraisopropoxide, 3-aminopropyltriethoxysilane, zirconium butoxide, and specific examples of metal salts include zirconium oxychloride, zirconium nitride, zirconium chloride, aluminum nitrate, aluminum Chloride and the like. The content of the metal alkoxide or metal salt is 5 to 20% by weight based on the total weight of the metal fine particle impregnation or adsorptive oxide pigment composition. If the content of the metal alkoxide is greater than 20% by weight, the size of the oxide particles increases, and if less than 5% by weight, the metal is not completely impregnated or adsorbed, which is not preferable.

In addition, in the above metal impregnated or adsorbed oxide pigment composition, any solvent can be used as long as it can dissolve each component constituting the composition. Specific examples include ethanol, methanol, propanol, butanol, water and the like, and the content thereof is preferably 80 to 94% by weight based on the total weight of the metal fine particle impregnation or the adsorbing oxide pigment composition.

The filter film 42 according to the present invention is formed on the substrate 41, and as shown in FIG. 4, the oxide pigment 43 powder impregnated or adsorbed with the metal particles of nano size is dispersed in the film. Have For reference, FIG. 1 shows a form in which metal fine particles are impregnated with an oxide, and FIG. 2 shows a form in which metal fine particles are adsorbed on an oxide surface. 3 shows a form in which some metal fine particles are impregnated with an oxide and some metal fine particles are adsorbed on an oxide surface.

The metal fine particles in the filter membrane of the present invention are at least one selected from the group consisting of gold, silver, copper, platinum, nickel, cobalt, rhodium, rubidium, lead and palladium fine particles, and the dielectric matrix is silica, titania, zirconia, alumina. At least one selected from the group consisting of: In this case, when two or more kinds of metal fine particles are used, two or more wavelength bands that can be selectively absorbed may be present. In addition, the filter membrane may be formed so that a plurality of layers having different wavelength bands of light that can be selectively absorbed may be formed.

It is preferable that the average particle diameter of the metal microparticles | fine-particles in a filter film is 10-50 nm. The method of controlling the size of the metal fine particles in the preparation of the metal colloid may be used any method known in the art. Specifically, for example, as the amount of the stabilizer (aminopropylsilane, merctosilane) increases, the size of the metal particles is smaller. Lose. The size of the metal particles to be formed varies depending on the type of solvent used, the type and content of the catalyst, the temperature and the reaction rate during the reduction reaction.

The filter film is formed between the inner surface of the panel of the cathode ray tube and the fluorescent film or is formed on the outer surface of the panel. Alternatively, the first filter film may be formed between the inner surface of the panel and the fluorescent film, and the second filter film may be formed on the outer surface of the panel.

The filter membrane of the present invention is applicable to a coating film for improving contrast of other various image display devices such as a plasma display panel in which phosphors are used in addition to the cathode ray tube, a filter film for a liquid crystal display, and various decorative colored coating films.

Hereinafter, the present invention will be described with reference to the following examples, but the present invention is not limited only to the following examples.

Preparation Example 1 Au Impregnated Oxide Pigment

0.44 g of 3-aminopropyltriethoxysilane was added to 75 g of ethanol and stirred for 10 minutes, and then 0.0012 mol of HAuCl ₄ · 4H ₂ O was added thereto. The mixture was stirred for 30 minutes, and then 0.015 mol of zirconium butoxide was added thereto and stirred for about 10 minutes. Thereafter, 10 ml of 25% aqueous ammonia was added to the mixture to form a precipitate. The precipitate obtained was dried at 250 ° C., and then calcined at 300 ° C. for 1 hour to prepare an Au impregnated or adsorbed oxide pigment.

Preparation Example 2.

0.44 g of 3-aminopropyltriethoxysilane was added to 75 g of ethanol and stirred for 10 minutes, and then 0.0012 mol of AgNO ₃ was added thereto. The mixture was stirred for 30 minutes, and then 0.015 mol of zirconium butoxide was added thereto and stirred for about 10 minutes. Thereafter, 10 ml of 25% aqueous ammonia was added to the mixture to form a precipitate. The precipitate obtained was dried at 250 ° C., and then calcined at 600 ° C. for 1 hour to produce an Ag impregnated or adsorbed oxide pigment.

Preparation Example 3.

0.44 g of 3-aminopropyltriethoxysilane was added to 75 g of ethanol, stirred for 10 minutes, and then, 0.0012 mol of Cu (NO ₃ ) ₂ .XH ₂ O was added thereto. The mixture was stirred for 30 minutes, and then 0.015 mol of zirconium butoxide was added thereto and stirred for about 10 minutes. Thereafter, 10 ml of 25% aqueous ammonia was added to the mixture to form a precipitate. The precipitate obtained was dried at 250 ° C. and then calcined at 650 ° C. for 1 hour to produce a Cu impregnated or adsorbed oxide pigment.

Example 1 Filter Film Formation of Cathode Ray Tube

1 g of Au-impregnated or adsorbed oxide pigment prepared in Preparation Example 1 was mixed with 2 g of methanol, 14.26 g of ethanol, and 2.74 g of polyvinylpyrrolidone (weight average molecular weight: 40,000), followed by 60 g of zirconia beads (0.3 mmΦ). To this was added and shaken for 2 hours with a paint shaker (paint shaker) to prepare a coating film for forming a filter film.

After forming a black matrix on a cleaned 17-inch monitor panel rotating at about 150rpm, 50cc of the coating solution for filter film formation was spin coated. Thereafter, the resultant was dried at 120 ° C. to complete a cathode ray tube having a filter membrane.

The contrast, brightness and durability of the cathode ray tube manufactured according to Example 1 were evaluated. Measurement data is shown in Table 1 below.

division Luminance (fL) Reflectance (fL) Contrast 400 lux 600 lux Example 1 55.2 0.997 1.620 56.37 Uncoated 60.9 2.154 3.574 29.27

As a result of the evaluation, the absorption wavelength of the filter membrane was found to be 575 nm, and it was confirmed that the contrast, brightness, and durability were excellent.

According to the present invention, by adjusting the resonance absorption effect of the metal fine particles impregnated or adsorbed in the oxide matrix to prepare a metal fine particles impregnated or adsorbed oxide pigment to absorb a relatively large amount of light in the vicinity of 575nm, using this filter When the film is formed, it can be used as a coating film for improving contrast, a filter film or various decorative colored coating films for various image display apparatuses. In particular, the cathode ray tube of the present invention employing the filter membrane not only selectively absorbs overlapping wavelengths of phosphor emission peaks, but also minimizes reflections on the outer and inner surfaces of the panel, thereby improving contrast without lowering the luminance.

Claims (11)

An oxide pigment, a dispersant, and a solvent impregnated or adsorbed with nano-sized metal particles that selectively resonate light of a specific wavelength range, The metal fine particle impregnation or adsorption oxide pigment, Metal fine particle-containing salt, oxide metal alkoxide (M (OR) n) (M is at least one selected from the group consisting of alkali metals, alkaline earth metals and transition metals, R is an alkyl group having 1 to 15 carbon atoms, n is 1 To 4) or metal salt (MX) (M is at least one selected from the group consisting of alkali metals, alkaline earth metals and transition metals, X is nitrate, chloride or sulfonate), impregnated with metal particulates consisting of catalyst and solvent Or a precipitate formed from an adsorption oxide pigment composition, and the precipitate is dried and heat-treated to obtain a composition for forming a filter film. The composition for forming a filter film according to claim 1, wherein the content of the metal fine particles impregnated or adsorbed oxide pigment is 1.5 to 3% by weight based on the total weight of the composition for forming a filter film. According to claim 1, wherein the dispersant is selected from the group consisting of polyvinylpyrrolidone, polyvinyl alcohol and hydroxypropyl cellulose, the content is 5 to 15% by weight based on the total weight of the composition for forming a filter film A composition for forming a filter film, characterized by the above-mentioned. The composition for forming a filter film according to claim 1, wherein the heat treatment temperature is 200 to 650 ° C when the metal fine particles are impregnated or adsorbed oxide pigment is manufactured. The salt of claim 1 wherein the metal particulate containing salt is a chloride, nitrate or sulfonate containing at least one metal selected from the group consisting of gold, silver, copper, platinum, nickel, cobalt, rhodium, rubidium, lead and palladium. , A composition for forming a filter film, wherein the content of the metal fine particle-containing salt is 0.1 to 5% by weight based on the total weight of the metal fine particle impregnation or adsorption oxide pigment composition. The method of claim 1, wherein the catalyst is at least one selected from the group consisting of ammonia water, sodium borohydride, sodium citrate, hydrazine hydrate, formamide, A composition for forming a filter membrane, wherein the content of the catalyst is 1 to 10% by weight based on the total weight of the metal fine particle impregnation or the adsorbing oxide pigment composition. The method of claim 1, wherein in the metal alkoxide M is at least one selected from the group consisting of Si, Ti, Zr and Al, n is 4, The content of the metal alkoxide or metal salt is a composition for forming a filter film, characterized in that 5 to 20% by weight based on the total weight of the metal fine particles impregnated or adsorbed oxide pigment composition. The filter membrane, characterized in that the oxide pigment impregnated or adsorbed by the metal fine particles that selectively resonance-absorb light of a specific wavelength band is formed by coating and drying the composition according to any one of claims 1 to 7. An image display element comprising the filter film according to claim 8. The image display element according to claim 9, wherein the image display element is a cathode ray tube, a plasma display panel or a liquid crystal display. The method of claim 10, wherein the filter film of the cathode ray tube is formed between the panel and the fluorescent film or on a surface exposed to the outside of the panel, or the first filter film is formed between the inner surface and the fluorescent film of the panel and the first filter film is formed on the outer surface of the panel. 2. An image display element characterized in that a filter film is formed.