JPS59943B2 - Color picture tube and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a screen that uses a phosphor coated with a filter material to form a filter layer that selectively transmits the emitted color of the phosphor and selectively absorbs external light. The present invention relates to a color picture tube and a method for manufacturing the same.

In order to improve the contrast under bright external light, a color picture tube has been proposed that has color filters for each layer of red, green, and blue phosphors.

The function of the filter is to selectively transmit the luminescent ability (brightness) and luminescent color of the corresponding phosphor layer without attenuating it, and to filter out light coming from outside the screen other than the luminescent color of the phosphor. It selectively absorbs light from outside the screen, and the filter function greatly reduces the amount of external light reflected on the screen surface, improving contrast.

There are, for example, three methods for forming these filters. The first method is to interpose corresponding filter substances in the red, green, and blue phosphor layers on the inner surface of the glass of the color picture tube. Mainly, methods have been proposed in which filter materials corresponding to each color are dispersed in a three-color phosphor slurry to form single layers of red, green, and blue filters.

The second method is to form red, green, and blue filter material layers between the phosphor screen surface and the inner surface of the glass panel, corresponding to the red, green, and blue phosphor layers, respectively.
A method of forming a single layer of red, green, and blue filters using A+ADC+filter material or frit glass+filter material has been proposed.

The third method is to coat the surface of phosphor particles with fine powder of a filter material corresponding to each emitted color, and use these phosphors to form a single layer of red, green, and blue filters. .

Of these three single-layer filter formation methods, the first method involves uniformly dispersing the filter material in the phosphor slurry;
When forming a single filter layer using the spin coating method, which is commonly used as a method for forming a fluorescent surface, some of the filter material dispersed in the slurry floats, resulting in a high concentration of filter material during continuous work that involves the collection process. The slurry is collected in high contrast, and the filter concentration in the slurry increases over time.

As a result, in order to adjust the slurry to contain a constant amount of filter material, slurry with a low concentration of filter material must be added at certain intervals, making process control difficult.

In addition, the fine particles of the dispersed filter material tend to remain on top of the other two color filter layers or at the position where the filter layer is planned to be formed, and the former has the drawback of causing a decrease in brightness, and the latter has the disadvantage of causing a color shift in the emitted light color and a decrease in brightness. .

The second method has the disadvantage that a filter layer must be provided between the phosphor layer and the inner surface of the glass panel, which increases the number of steps for forming the filter layer.

The third method is to use a phosphor coated with a filter material when preparing a slurry of red, green, and blue phosphors, and form a single layer of the filter by a spin coating method, which is commonly used as a method for forming a phosphor surface. This is an excellent method since it is possible to easily obtain a filter layer having a constant concentration of filter material as long as the filter material coated on the surface of the phosphor particles does not peel off during the formation of the filter layer.

Polyvinyl alcohol (PV) is currently used as this type of phosphor.
A), phosphor particles coated with polyvinylpyrrolidone (PVP), gelatin, etc. with a filter substance attached to them; phosphor particles with a filter substance coated with the above organic substance attached to the surface; There is a method in which the filter material is coated with an organic film such as nitrocellulose or an inorganic film such as water glass, but peeling of the filter material is inevitable when forming a single layer of the filter, and this has the same drawbacks as described in the first method.

The present invention provides a color picture tube having a screen in which a filter layer is formed using a phosphor coated with a filter material, which causes no peeling of the filter material and less reduction in brightness due to the coating of the filter material, and a method for manufacturing the same.

That is, the object of the present invention is to use a phosphor coated with a filter material in which a silane film is interposed between the phosphor and the filter material so that the filter material does not peel off, thereby eliminating reduction in brightness and color shift due to filter material residue. In addition, the silane film decomposes during high-temperature treatment to decompose organic matter in the phosphor layer, and due to the presence of the ultrafine silica layer that remains between the phosphor and the filter material, a diffused reflection effect of light occurs when the phosphor emits light. A color picture tube having a screen formed with a single layer of filter for improving brightness is provided.

The phosphor used in the present invention is manufactured by forming a thin continuous silane film 2 on the surface 1 of the phosphor particles using, for example, a silane coupling agent represented by the general formula R5tCX)3, as shown in FIG. It is coated with fine particle powder 3 of a filter substance that corresponds to the color of the body's emitted light.

Here, R represents an organic functional group such as an amine group, an organ group, a mercapto group, a vinyl group, an epoxy group, or a methacryloxy group, and X represents a hydrolyzable alkoxy group, etc. are essentially unrelated.

When a single filter layer is formed by using a phosphor coated with a filter substance through a silane film, the filter substance does not peel off when the phosphor surface is formed, so that a different type of filter may be placed in the intended position of another filter layer or on top of the filter layer. There are no fine particles of material, and no deviation in the color of the emitted light is observed when illuminated with a picture tube.

Furthermore, even if a single filter layer is formed in a continuous operation involving the recovery process, the amount of filter material contained in each filter layer does not change, and no change in quality is observed due to an increase or decrease in the amount of filter material.

Furthermore, when the organic substances in the fluorescent blood are thermally decomposed in a high-temperature furnace, the silane film is also decomposed as shown in Fig. 2, and the ultrafine silica particles 4 constituting the silane film form on the surface of the fluorescent particles 1.
and the filter substance fine particle powder 3.

As a result, as shown schematically in FIG. 3 with and without ultrafine silica particles, when the phosphor emits light with an electron beam 5 due to the presence of ultrafine silica particles 4, the light 6 is transmitted to the surface of the ultrafine silica particles 4. The amount of light that is diffusely reflected by the filter and passes through the phosphor again to the outside of the filter increases.

If we compare the brightness of a picture tube with a single filter layer containing ultrafine silica particles and a picture tube with a single filter layer without ultrafine silica particles, the former has a lower rate of brightness reduction due to filter particle coating than the latter. It has the advantage of being very rare.

A method for forming a silane film on the surface of the phosphor particles is to stir and mix the phosphor particles using a V-type mixer or a Henschel mixer, and then drop or spray an aqueous solution of a silane coupling agent onto the surface of the phosphor particles. A dry method in which a silane coupling agent solution is added dropwise to a slurry-like phosphor to form a silane film, and after the dropwise addition is complete, the silane coupling agent is stirred thoroughly and left to stand. a slurry method in which a silane film is formed by settling and concentrating the phosphor particles and then drying the phosphor to remove residual moisture;
Furthermore, there is a spray method in which a silane film is formed by spraying an aqueous solution of a silane coupling agent onto the phosphor immediately after it has been taken out of the furnace and removing moisture using the heat of the phosphor.

Among these methods, the dry method and slurry method give good results when considering the formation of a uniform silane film on the surface of the phosphor particles.

Further, the pH of the solution for forming a silane film varies depending on the silane coupling agent used, and if the pH is incorrectly adjusted, the silane film may not be formed.

Therefore, it is necessary to use acetic acid or sodium hydroxide to adjust the pH to the optimum value.

The appropriate amount of the silane coupling agent used to form the silane film in the present invention is preferably 0.2 to 6% based on the weight of the phosphor, but about 0.5 to 4% exhibits particularly excellent properties.

The method of coating the phosphor particles on which a silane film has been formed is to coat the phosphor particles with a filter material by adding water, a surfactant to help disperse the filter material particles in an aqueous solution of the filter material, and adding a surfactant to prevent agglomeration. Thoroughly disperse the filter material particulate powder by time milling or ultrasonication.

Thereafter, an organic substance such as polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), gelatin or acrylic emulsion is added and sufficiently stirred to enclose the filter substance fine particles in the organic substance.

The phosphor is added to the aqueous solution thus prepared with stirring, and after stirring for a certain period of time, it is allowed to stand still to allow the phosphor covered with the filter material to settle, and after concentration, it is dried.

When phosphor particles on which a silane film is formed using a silane coupling agent as described above are coated with a filter substance,
Observation using an electron microscope shows that the filter material uniformly covers the surface of the phosphor particles.

Further, when this phosphor is used to form a slurry, no peeling of the filter material is observed, and a filter layer having a constant amount of filter material can always be obtained even in continuous operations involving the recovery process.

Next, an example of a method for manufacturing a phosphor added with a filter material for use in a color picture tube of the present invention will be described.

A fired product of blue phosphor ZnS:Ap produced under appropriate conditions IK! ; / is placed in a ■-type blender and as stirring begins, the silane coupling agent aqueous solution is injected from the dropping funnel into a hollow forced stirring bar that rotates at high speed.

The silane coupling agent aqueous solution used was 15 g of silane coupling agent CHs S t (OCH3) a.
A solution dissolved in 85 cc of distilled water was used, and the dropping rate was adjusted to 25 to 30 cc per minute.

After dropping the entire amount of the treatment solution and stirring for 5 to 10 minutes, transfer the wet phosphor to dry skin and spread it evenly to a thickness of 2 to 3 CIrL and put it in a forced circulation dryer at 150℃ for about 1 hour. I put it on to dry.

After drying, it was passed through a 200 mesh sieve to form a phosphor with a silane film formed thereon.

The filter material used was cobalt aluminate blue pigment, which corresponds to the emission color of the blue phosphor.The composition of Glass Peas 6009, 150 cc of water, 300 fI of pigment, and 10 cc of surfactant was continuously milled for one week to completely remove the pigment. After loosening, add 990 cc of distilled water and 50 ml of polyvinyl alcohol.
The filter material was diluted into an aqueous solution consisting of p and stirred for 1 hour to obtain a filter material dispersion solution.

To coat the filter material, add the blue phosphor particles covered with the silane film little by little to the cobalt aluminate blue pigment dispersion solution while stirring, and after adding the entire amount, stir thoroughly for about 20 minutes, then let it stand still for 30 minutes. I made him put it there.

Thereafter, the turbid liquid was removed, and the precipitated blue pigment-coated phosphor was concentrated and filtered. After concentration, it was transferred to a drying plate and spread evenly to a thickness of 2 to 3 CIfL, and then placed in a forced circulation dryer and dried at 150°C for about 1 hour. Ta.

After drying, it was thoroughly loosened by passing it through a 200-mesh sieve.

When the blue pigment-coated blue phosphor prepared in this manner was observed under an electron microscope, it was found that the fine powder of the blue pigment uniformly covered the surface of the blue phosphor particles.

Further, even when this phosphor was put into a slurry in a solution consisting of a photosensitizer, a sensitizer, and a surfactant, no pricking of the blue pigment was observed.

That is, to explain a method of manufacturing a color picture tube using a phosphor to which such a filter substance is added using a diagram, the surface of the phosphor particles is coated with fine particles of cobalt aluminate blue pigment via a silane film. A blue phosphor with a filter particle layer formed thereon was loosened using glass beads, and then added to a solution consisting of polyvinyl alcohol (PVA), ammonium dichromate (ADC), and a surfactant and stirred to form a slurry.

This slurry was applied to the inner surface of the glass panel 7 consisting of a black light absorbing layer 8 and a green phosphor layer 9 as shown in FIG. The latent image of the position of the blue phosphor is printed on the inner surface of the panel by ultraviolet rays through the shadow mask, and the non-exposed areas are dissolved by hot water development to obtain the desired blue filter layer 11 as shown in Fig. C.

Next, a red phosphor slurry was applied thinly and uniformly to the inner surface of the panel having a green phosphor layer 9, a black light absorption layer 8, and a blue filter layer 11, as shown in Figure d, by a spin coating method to obtain a phosphor film. After that, a latent image of the position of the red phosphor was printed on the inner surface of the panel by ultraviolet rays through a shadow mask, and unexposed areas were dissolved by hot water development to obtain the desired red phosphor layer 12.

By the above method, a phosphor surface consisting of a black light absorbing layer, a green phosphor layer, a blue filter layer, 11 a red phosphor layer 12 was obtained.

Next, this glass panel with a fluorescent surface was used and subjected to various steps to produce a color picture tube.

When the color picture tube thus obtained was illuminated and the fluorescent surface was observed, there was no residue of blue pigment fine particles in the green and red phosphor layers, and therefore no decrease in brightness or deviation in emission color was observed. , and the contrast was greatly improved due to the absorption of external light by the blue filter layer.

Furthermore, the reduction in brightness due to blue pigment coating was approximately % compared to that using a blue phosphor coated with a filter material without a silane film, confirming that the brightness was improved by ultrafine silica particles.

In the above embodiments, the case where a blue phosphor is coated with a blue pigment has been described, but it can also be applied to cases where a red phosphor is coated with a red pigment and a green phosphor is coated with a green pigment. Furthermore, a black material or the like may be added to each of the phosphors along with the respective pigments, and it goes without saying that the present invention can also be applied to a color picture tube without the black light absorbing layer 8 as is.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of pigmented phosphor particles before thermal decomposition, which is suitable for the color picture tube of the present invention, and FIG. 2 is a sectional view showing the structure of the pigmented phosphor particles in FIG. 1 after thermal decomposition. , FIG. 3 is an explanatory sectional view showing a state in which an electron beam is irradiated with the pigmented phosphor particles shown in FIG. 2, and FIG. 4 is a sectional view showing the main parts of the manufacturing process of the color picture tube of the present invention. It is. 1... Fluorescent particles, 3... Pigment particles,
5...Electron, 8...Black light absorption layer.

Claims (1)

[Scope of Claims] 1. In a color picture tube having a screen covered with layers of phosphor particles emitting blue, green, and red colors in a desired shape upon impact with an electron beam, the phosphor particles A silica film is substantially interposed between at least one of the particles and a pigment that transmits an emission color substantially the same as the emission color of the phosphor particles and substantially absorbs other colors. A color picture tube featuring 2. In the color picture tube according to claim 1, the phosphor particles are blue-emitting phosphor particles, and the pigment is made of a pigment that transmits substantially blue light and substantially absorbs other colors. A color picture tube characterized by: 3. A layer group of phosphor particles that emit blue, green, and red colors is deposited in a desired shape by the impingement of an electron beam, and at least one layer of phosphor particles that emit blue, green, and red colors is formed internally. In a method for producing a color picture tube, in which a pigment is formed on phosphor particles of a species, the pigment transmits light of an emission color substantially the same as the emission color of the phosphor particles and substantially absorbs other colors. After forming a silane coupling material layer that becomes substantially silica using at least one method of dry method, slurry method, or spray method, the pigment is coated on the phosphor particles. A method of manufacturing a color picture tube, characterized in that: 4. In the method for manufacturing a color picture tube according to claim 3, the means for applying the pigment to the phosphor particles is a phosphor in which the silane film is formed in an aqueous solution in which the pigment is dispersed. 1. A method for manufacturing a color picture tube, which comprises adding and depositing body particles. 5. In the method for manufacturing a color picture tube according to claim 3, the means for applying the pigment to the phosphor particles forms the silane film in a dispersion of the pigment dissolved in an organic substance. 1. A method for manufacturing a color picture tube, which comprises adding and depositing a phosphor.