KR100366080B1 - Preparing method for cathode layer tube improved in contrast - Google Patents

Abstract

The present invention relates to a method for manufacturing a cathode ray tube, the method according to the present invention comprises the steps of preparing a panel having an inner surface to which the electron beam is projected and an outer surface exposed to the outside; Applying to one side of the panel a coating liquid comprising a metal particulate colloidal solution and a matrix precursor; And firing the panel coated with the coating liquid at 180 to 200 ° C. to obtain a filter membrane in which nano-sized metal fine particles are dispersed.

Description

Preparing method for cathode layer tube improved in contrast

The present invention relates to a method for producing a cathode ray tube (CRT), and more particularly a method for producing a cathode ray tube with improved contrast by using resonance absorption of metal particles.

Cathode ray tubes display the screen by emitting red (R), blue (B) and green (G) phosphors, which are respectively applied between the black matrix (BM) in dots or stripes, by the collision with the electron beam emitted from the electron gun. Display device.

Among the light emitted from the fluorescent surface of the cathode ray tube, the light visible to the human eye can be classified into two types. That is, the light emitted by the light emission of the phosphor due to the collision with the electron beam and the light of the external light source in the environment where the CRT is used are the light reflected from the surface of the fluorescent surface of the cathode ray tube.

The light reflected from the surface of the cathode ray tube reflects the light from the external light source into two categories: one is the light reflected from the outer surface of the panel, and the other is passed through the panel and reflected at the interface between the panel and the phosphor. It is the light that comes out.

The light produced by the phosphor is a light that the cathode ray tube displays to display the information to be displayed, and has a peak in a specific wavelength region and is displayed in various colors by a combination thereof. Therefore, the reflected light of the external light source having a continuous wavelength in the visible light has light of a wavelength other than the light emitted by the phosphor, which acts as a factor to inhibit the contrast of the screen.

This phenomenon will be described in more detail by taking the P22 series phosphor, which is widely used as a phosphor of a cathode ray tube, as an example. The ZnS: Ag phosphor (blue) has the main peak at 450 nm, the ZnS: Au, Cu, Al phosphor (green) at 540 nm, and the Y ₂ O ₂ S: Eu phosphor (red) at 630 nm.

In other words, the light due to the external light reflection is derived from a white light source having a continuous light emission distribution in the entire visible light region, unlike the light emission distribution of the phosphor, so that much light in the region between the light emission peaks of the phosphor It is included.

In addition, the blue and green phosphors have a relatively broad peak shape, and overlapping portions exist at 450 nm to 550 nm, and the peaks of the red phosphor have many side bands around 575 nm, all of which lower the contrast of the cathode ray tube. It is known as a factor. In addition, since the luminous efficiency of external light and eyes is large in the vicinity of 575 nm, selective absorption of light in the vicinity of 575 nm can effectively absorb external light and overlap between the phosphors without lowering the luminous efficiency of the phosphor. By absorbing light of the wavelength can improve the color purity.

On the other hand, in the case of selectively absorbing the light of 575nm, the overall color of the cathode ray tube (body color) has a blue violet color, so in order to exhibit a complementary color effect to give achromatic color, it is preferable to additionally absorb light around 410nm.

Therefore, in order to solve the above problems, efforts have been made to improve the contrast of cathode ray tubes by selectively absorbing light in the vicinity of 575 nm, 500 nm and 410 nm.

Specifically, for example, US Pat. Nos. 5,200,667, 5,315,209 and 5,218,268 disclose a method of forming a film layer comprising a dye or pigment absorbing light of a particular wavelength on the outer surface of a fluorescent tube of a cathode ray tube. As another method, there is a method of reducing external reflection by optical interference by coating a plurality of transparent oxide layers having different refractive indices with the outer surface of the fluorescent surface of the cathode ray tube and adjusting the thickness of the coating.

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, U.S. Patent Nos. 4,019,905, 4,132,919 or 5,627429, etc. form an intermediate layer containing a pigment capable of absorbing light of a specific wavelength band between the inner surface of the panel and the fluorescent film. A method is disclosed, and U.S. Patent Nos. 5,068,568, 5,179,318 and the like 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.

Accordingly, the technical problem to be achieved by the present invention is to effectively minimize the surface or internal reflection of the cathode ray tube panel and to absorb a lot of overlapping wavelengths of the phosphor emission peaks more effectively than the case of using the optical interference phenomenon due to the refractive index or only the pigment. By providing a method for producing a cathode ray tube that can improve the contrast under milder process conditions.

The present invention to solve the above technical problem,

Preparing a panel having an inner surface on which the electron beam is projected and an outer surface exposed to the outside;

Applying to one side of the panel a coating liquid comprising a metal particulate colloidal solution and a matrix precursor; And

It provides a cathode ray tube manufacturing method comprising the step of firing the panel coated with the coating liquid at 180 to 200 ℃ to obtain a filter film in which nano-sized metal particles are dispersed in a matrix.

According to one embodiment of the present invention, in preparing the metal particulate colloidal solution, one or two selected from the group consisting of HAuCl ₄ , NaAuCl ₄ , AuCl _3, and AgNO ₃ are used as metal salts, and the content of the dielectric matrix total The absorption wavelength and the absorption intensity of light which can be selectively absorbed can be adjusted by adjusting the amount of molar number from 2.62 to 17 mol%.

According to another embodiment of the present invention, tetraethylorthosilicate (TEOS) and tetraisopropoxide (TIP) as the matrix precursor; Alternatively, by using zirconium ethoxide and aluminum butoxide, and controlling the refractive index of the matrix by adjusting each component ratio of 4: 1 to 4: 5, the absorption wavelength and absorption intensity of light that can be selectively absorbed can be adjusted.

The filter film may be formed between the panel and the fluorescent film, or may be formed on a surface exposed to the outside of the panel.

When the filter film is formed on the outer surface of the panel, further comprising a conductive film containing indium tin oxide between the filter film and the outer surface of the panel, and the filter film formed on the outer surface of the panel to function as an antireflection film at the outermost portion of the panel. Can be.

The metal fine particles are preferably one or more metal fine particles selected from the group consisting of gold, silver, copper, platinum and palladium fine particles.

The matrix preferably consists of one or more dielectrics selected from silica, titania, zirconia and alumina.

The filter film may contain two or more kinds of metal fine particles so as to have two or more wavelength bands of light selectively absorbed.

Hereinafter, the present invention will be described in more detail.

The contrast enhancement of the cathode ray tube can be achieved by reducing the reflection on the outer and inner surfaces of the panel and selectively absorbing light in the wavelength band near the wavelength of 575 nm of the red phosphor or between each main peak of the red, green and blue phosphors.

In the present invention, by using the Surface Plasma Resonance (SPR) phenomenon of the metal particles to absorb the light of a specific wavelength between the emission peaks of the phosphor, it is characterized by improving the contrast of the cathode ray tube.

Resonance absorption of metal particles refers to absorption of visible light as the conduction electrons on the particle surface resonate with an electric field from which nanosized metal particles dispersed in a dielectric matrix such as silica, titania, zirconia, or alumina are applied from the outside. It refers to a phenomenon having a band (J. Opt. Soc. Am. B vol. 3, No. 12 / Dec. 1986, pp 1647-1655). The term "nanosize" herein refers to a size of several nanometers to several hundred nanometers, that is, at least 1 nanometer, less than 1 micron.

Specifically, for example, when the dielectric matrix is silica and the metal fine particles of 100 nanometers or less are gold (Au), 530 nm in the case of silver (Ag), 410 nm in the case of copper (Cu), and light around 575 nm is strongly intensified. Absorb. In the case of platinum (Pt) or palladium (Pd), it absorbs broadly over 380 nm to 800 nm depending on the type of matrix.

The position of the absorption wavelength is determined by the type of the dielectric matrix (ie, refractive index), the type of metal, the size of the metal fine particles, and the like, and the absorption peak becomes longer as the overall refractive index is increased due to the addition of the second component dielectric having a large polarization degree. To the side.

For reference, the refractive index of silica is 1.52, the refractive index of alumina is 1.76, the refractive index of zirconia is 2.2, and the refractive index of titania is 2.5-2.7.

Types of metals include elements classified as metals in the periodic table, ie transition metals, alkali metals, alkaline earth metals, and the like. Among them, gold, silver, copper, platinum, and palladium are more preferable since absorption occurs in the visible light region.

Although somewhat different depending on the type of metal, in general, when the size of the metal fine particles is about 100 nanometers or less, the larger the size of the fine particles, the greater the absorption strength. However, in the case of more than 100 nanometers, as the size increases, the position of the absorption peak shifts toward the longer wavelength. Thus, the size of the metal fine particles can affect both the absorption strength and the position of the absorption peak. The absorption strength also depends on the size and content of the metal fine particles and the amount of the second component dielectric added.

Specific examples of improving the contrast of a cathode ray tube using resonance absorption of metal fine particles may be referred to Korean Patent Application Nos. 99-31859 and 99-34356.

However, in the above method, since the metal fine particles are used in the form of a metal salt with a matrix precursor, water, and an acid catalyst, the sol-gel method is applied, so that it is necessary to undergo a firing step above the pyrolysis temperature of the metal salt. The thermal decomposition temperature of the metal salt reaches about 200 ° C for gold (Au), about 500 ° C for silver (Ag), and about 650 ° C or more for copper (Cu). Therefore, when using the sol-gel method, firing of about 30 minutes or more at a high temperature above this pyrolysis temperature is essential.

Therefore, the present invention is to propose a method that can achieve the desired purpose only by heat treatment at a temperature far lower than the pyrolysis temperature of the metal salt, that is, the temperature at which the matrix can be cured, preferably at 180 to 200 ° C. That is, the present invention forms a metal particulate film using a nano-sized metal colloid instead of a metal salt.

In this case, in order to obtain a desired absorption wavelength band, there may be a method of initially adjusting the size of the metal fine particles or combining matrixes having different refractive indices in the preparation of the metal colloid.

Specifically, for example, in order to absorb a wavelength located near 575 nm, for example, a gold (Au) colloid and silica matrix having an absorption peak located at 530 nm, the following method can be considered.

First, titania, zirconia or alumina having high polarization and refractive index as the second component is added to the silica matrix to shift the absorption peak toward the longer wavelength, and the intensity of the absorption peak is controlled by the addition amount. The intensity of the absorption peak must be determined in consideration of the permeability of the panel, the concentration of the filter membrane, and the like. Generally, it is preferable that the peak width is narrow and the intensity is large.

Second, the size of the metal fine particles is adjusted without adding the second component. That is, the resonance absorption wavelength is shifted toward the longer wavelength when the average particle diameter of the fine particles is added to the matrix to prepare the metal colloid to 30 to 40nm.

In the preparation of the metal colloid, the method of controlling the size of the metal fine particles may be any method known in the art. Specifically, for example, as the amount of polyvinylpyrrolidin added as a dispersion stabilizer increases, the size of the metal particles is small. As the molecular weight of the polyvinylpyrrolidine used increases, the size of the metal particles decreases. The size of the metal particles to be formed varies depending on the type of organic solvent used, the type and amount of the reducing agent, and the temperature and speed during the reduction reaction.

On the other hand, in the case of selectively absorbing light around 575nm, a plurality of filter membranes may be used to absorb light around 410nm to give an achromatic color to the overall color, depending on the specific wavelength or absorption intensity absorbed by the first filter membrane. The content of the metal fine particles included in the second filter membrane may vary.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples are intended to help the understanding of the present invention, but the scope of the present invention is not limited thereto.

<Example 1>

1 g of HAuCl ₄ H ₂ O was added to 89 g of ethanol, followed by stirring. Then, 10 g of polyvinylpyrrolidone (PVP, molecular weight 40000) was mixed and stirred for 1 hour. While stirring the solution again vigorously, a solution of 0.3 g of NaBH ₄ dissolved in 2 g of pure water was added at once and stirred for 12 hours to prepare a 1 wt% gold (Au) colloidal solution. The size of the gold fine particles thus prepared was measured with an electron projection microscope, and the average particle diameter was about 15 nm.

Meanwhile, 4.5 g of tetraethylorthosilicate (TEOS) was added to a solvent in which 30 g of methanol, 30 g of ethanol, 12 g of n-butanol, and 4 g of pure water were added, followed by stirring for about 24 hours to obtain a solution A.

In addition, 36 g of ethanol, 1.8 g of pure water, and 2.5 g of hydrochloric acid (35%) were sequentially added to 25 g of titanium isopropoxide (TIP), followed by stirring for 24 hours to prepare Solution B.

The coating solution was prepared by adding 8 g of the 1 wt% gold colloidal solution, 12 g of solution A, 3 g of solution B, and 12 g of ethanol to the mixed solution.

On a cleaned 17-inch monitor panel that rotates at about 150 rpm After forming the black matrix 50 ml of the coating solution was added dropwise and spin-coated. The coated panel was put into a kiln maintained at 180 ° C. and fired for 30 minutes to complete a cathode ray tube.

As a result of the performance test of the manufactured cathode ray tube, the absorption wavelength of the filter layer was found to be 575 nm, and the contrast, brightness, and durability test results were all good.

<Example 2>

It was carried out in the same manner as in Example 1 except that NaAuCl ₄ was used instead of HAuCl ₄ as the metal salt.

<Example 3>

The same procedure as in Example 1 was carried out except that AuCl ₃ was used instead of HAuCl ₄ as the metal salt.

<Example 4>

Zirconia using zirconium ethoxide (Zr (OC ₂ H ₅ ) ₄ ) and aluminum sec-butoxide (Al (OC ₄ H ₉ ) ₄ ) instead of tetraethylorthosilicate (TEOS) and titanium isopropoxide (TIP) The same process as in Example 1 was conducted except that the molar ratio between and alumina was 4: 1.

Example 5

A second coating liquid was prepared in the same manner as in Example 1, except that AgNO ₃ was used instead of HAuCl ₄ as the metal salt and the silver content was 5 mol%, and the coating liquid of Example 1 was prepared as the first coating liquid. It was. A cathode ray tube was manufactured in the same manner as in Example 1 except that the first coating solution was spin coated on the panel and then the second coating solution was spin coated.

<Example 6>

HAuCl ₄ · 4H ₂ O and AgNO ₃ were used in the same manner as in Example 1 except that the gold and silver contents were 12 mol% and 5 mol%, respectively, based on the total moles of the dielectric matrix. .

As a result of the performance test of the cathode ray tube manufactured in Example 5, the absorption wavelength of the filter layer was found to be 530 nm and 410 nm, and the contrast, brightness, and durability test results were all good.

In the cathode ray tube manufacturing method according to the present invention, since the fine particle metal colloid is used to prepare the metal fine particle dispersion layer by low temperature firing below the metal salt decomposition temperature, the process conditions are not only mild but also absorbed by a simple method compared to pigments or dyes. Purity or intensity can be adjusted. Therefore, the cathode ray tube manufactured by the method according to the present invention can not only selectively absorb overlapping wavelengths of phosphor emission peaks, but also minimize reflection on the outer and inner surfaces of the panel, thereby improving contrast without deteriorating luminance. .

Claims (9)

Preparing a panel having an inner surface on which the electron beam is projected and an outer surface exposed to the outside; Applying to one side of the panel a coating liquid comprising a metal particulate colloidal solution and a matrix precursor; And And firing the panel coated with the coating solution at 180 to 200 ° C. to obtain a filter membrane in which nano-sized metal fine particles having a size of 1 nanometer or more and less than 1 micron are dispersed in a matrix. The method of claim 1, wherein in the preparation of the metal fine particle colloidal solution, one or two selected from the group consisting of HAuCl ₄ , NaAuCl ₄ , AuCl _3, and AgNO ₃ are used as metal salts, and the content is based on the total mole number of the dielectric matrix. 2.62 to 17 mol% by controlling the absorption wavelength and absorption intensity of light that can be selectively absorbed by the cathode ray tube manufacturing method characterized in that. The method of claim 1, wherein the matrix precursor is tetraethylorthosilicate (TEOS) and tetraisopropoxide (TIP); Or by using zirconium ethoxide and aluminum butoxide, and controlling the refractive index of the matrix by adjusting the respective component ratios from 4: 1 to 4: 5 to adjust the absorption wavelength and absorption intensity of light that can be selectively absorbed. Cathode ray tube manufacturing method. The cathode ray tube manufacturing method according to claim 1, wherein the filter film is formed between the panel and the fluorescent film. The cathode ray tube manufacturing method according to claim 1, wherein the filter membrane is formed on a surface exposed to the outside of the panel. delete The method of claim 1, wherein the metal fine particles are gold, silver, copper, a cathode ray tube manufacturing method which is characterized in that the one or more metal particles selected from the group consisting of platinum and palladium particles. The method of claim 1, wherein the matrix is a cathode ray tube manufacturing method, characterized in that the dielectric consisting of one or more selected from silica, titania, zirconia and alumina. delete