KR900005889B1 - Face plate forming method of cathode ray tube - Google Patents

Abstract

A method for forming a fluorescent screen for a cathode ray tube comprises forming a fluorescent body layer, an organic film and a metal reflective membrane in order on the inside of the face plate, removing the organic film by heating the face plate, and sticking the membrane to the layer. The organic film is formed by coating the layer with a film liquid, and drying the coated layer. The film liquid comprises acryl resin emulsion, and polysaccharides or acrylic acid salt.

Description

Method of Forming Fluorescent Surface for Cathode Ray Tube

1 is a partial cross-sectional view of a fluorescent surface formed in accordance with the present invention.

2 and 3 are face plate cross-sectional views of the process of forming the fluorescent surface according to the present invention.

4 is a plan view showing the structure of the organic film formed in the present invention.

5 is a cross-sectional view showing the structure of the organic film formed in the present invention.

* Explanation of symbols for main parts of the drawings

1: face plate 2: phosphor particle

3: phosphor layer 4: organic film

5: aluminum vapor deposition film 6: acrylic resin

7: alginic acid ester 11: film liquid

The present invention relates to a method of forming a cathode ray and a fluorescent surface, in particular, a method of forming an organic film layer as a lower base layer of a metal thin film.

Conventionally, for example, in the case of forming a fluorescent surface of a color water pipe, three kinds of phosphors which emit light of red, blue, and green upon irradiation of an electron beam on the inner surface of a face plate are formed in a point shape or a line shape. Arranged to be installed.

Then, the surfaces of the phosphor layers are coated with an organic film, and a metal deposition film made of aluminum or the like is formed on the surface of the organic film, and then the face plate is heated to decompose and remove the organic film, thereby depositing the metal deposition film on the surface of the phosphor layer. To stick to it.

In this case, the organic film fills and smoothes the uneven portion of the surface due to the particulate matter of the phosphor, so that the metal deposition film constituting the reflective film is formed into a uniform continuous film, and the surface of the phosphor layer has a good surface. As used to obtain a shape, such an organic film is decomposed and removed by heating after the metal deposition film is formed, and is usually formed by coating and drying a liquid solution mainly composed of an aqueous emulsion of acrylic resin. At this time, the resin becomes the most dense packed state of the emulsion zone particles due to the moisture layer existing between the individual emulsion zone particles, and at the same time, the particles are melted together by heat to form a uniform continuous value, resulting in the formation of an organic film. will be. Accordingly, in order to form a good organic film, uniform drying and rapid drying by heating are required.

By the way, even though the film is dried and dried at a sufficient temperature to obtain a good organic film and to form a metal deposition film having a good glass surface, the metal deposition film is pushed up due to the gas pressure generated when the organic film is decomposed and removed in the next heating step. The so-called (fire air) swelling phenomenon could occur.

As a result, since the metal deposition film is released from the phosphor layer and adheres to the electrode portion, the breakdown voltage is reduced or the fluorescent surface of the part where the metal deposition film is peeled off has a defect that the emission luminance is lowered. It was necessary to form a way out of the gas.

For this reason, conventionally, P.V.A. A mixture of inorganic materials such as boric acid ester and silicate or colloidal silica was used to form a gas outlet by forming cracks in the formed organic film.

However, according to the method of forming the fluorescent surface, after the heating step, not only the ratio of silicic acid compounds remaining in the phosphor layer is high, but also the thermal degradation is poor and the smoothness of the organic film is impaired. There is a problem that the luminance of the fluorescent surface is lowered because the phosphor emission leaks from the crack and reduces the light emitted in front of the face plate.

Accordingly, an object of the present invention is to form an organic film having a good smooth surface in the light of the above-mentioned conventional situation, and at the time of thermal decomposition thereof, a phenomenon in which the metal deposition film on the organic film becomes rough or excited does not occur, and the light reflection efficiency is also high. It is to provide a method for forming a metal deposition film.

In order to achieve the above object, the present invention uses a composition liquid containing an acrylic resin emulsion as a main component and a small amount of an additive having poor compatibility with the acrylic resin as a whipping liquid used in forming an organic film. do.

For example, as the additive, a water-soluble polysaccharide having 6 rings or a compound thereof, or polyacrylic acid or polyacrylate is used.

First, a description will be made of an example of using a water-soluble polysaccharide having 6 rings or a compound thereof as an additive. As a film forming liquid (hereinafter referred to as "film liquid") used for forming an organic film, the acrylic emulsion has a main component, Furthermore, the composition which added 0.01-1.0 weight% of water-soluble polysaccharide which has 6 rings, or its compound is used.

In the organic film formed by adding a small amount of the above polysaccharide having poor compatibility with the main acrylic resin, the polysaccharide is separated into an island-in-sea phase in the acrylic resin to form a recess. A gap is formed in the metal vapor deposition film, and since the decomposition gas generated by heating can be emitted at this interval, swelling of the metal vapor deposition film can be prevented. As an acrylic emulsion which is a main component, the aqueous emulsion zone of polymers or copolymers, such as acrylic acid or acrylic acid ester, methacrylic acid or methacrylic acid ester, styrene, acrylonitrile, is used.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1

First, as shown in FIG. 1, a phosphor layer 3 formed of phosphor particles 2 of three colors of red, blue, and green is formed on the inner surface of the face plate 1. Known techniques such as the method used and the method of directly attaching the phosphor powder to the adhesive film can be used.

Next, a film solution of pH 3.0 to 4.0 having the following composition is applied and dried on the phosphor layer 3 to form an organic film 4, and then an aluminum deposition film 5 is formed.

In applying the film of the above composition, as shown in FIG. 2, the face plate 1 in which the phosphor layer 3 was formed is made to face upward, and the film liquid 11 which has the said composition is inject | poured. Subsequently, the face plate 1 is slowly rotated to open the film liquid 11 over the entire inner surface thereof, and then the face plate 1 is inclined to discharge the overflowed film liquid 12 as shown in FIG. Subsequently, the face plate 1 is rotated at a high speed to make the coating state of the film liquid 11 uniform, and then heated and dried to form the organic film 4.

At this time, as shown in FIG. 4, the organic film 4 is separated from the acrylic resin 6 and the alginic acid ester 7 to show a sea island-like structure. Here, a monolayer as shown in FIG. 5 is formed at the boundary between the alkonic acid ester 7 and the acrylic resin 6 separated on the islands. Therefore, when aluminum is deposited on the organic film 4 to form the aluminum deposition film 5, a gap 5a is formed in the aluminum deposition film 5, and thereafter, the organic film 4 is thermally decomposed and removed by heating. In the process, the cracked gas does not escape at this interval 5a to push up the aluminum deposition film 5, and the luminance is low since the smoothness and light reflectance of the aluminum deposition film 5 are small. High fluorescent surface can be obtained.

In the above-described embodiment, when the addition amount of the alginic acid ester is excessive, the sea island structure of the organic film 4 becomes too large, and the smoothness may be impaired. Therefore, the addition amount should be 1.0% by weight or less, and about 0.2% by weight. Is the best. On the other hand, when the added amount is 0.01% by weight or less, this island-in-the-sea structure is not formed, thereby obtaining an effect of preventing swelling of aluminum.

When the added amount is the minimum amount that can prevent the swelling of the aluminum, in the process of thermal decomposition of the organic film, since the amount of air supplied is insufficient, sufficient decomposition and removal are not performed. The side face 1a of the plate 1 becomes brown and becomes unsightly.

Therefore, in order to prevent this, it is preferable to add a water-soluble or emulsion type of an organosilicon compound such as silicon. In this case, if the addition amount is excessive, there is a possibility that the residue of silicon increases and the luminance of the fluorescent surface may be lost. It is preferable that the addition amount of an organosilicon compound is 10 weight% or less, and about 2-3 weight% is the most suitable. Thus, as organosilicon compounds which promote decomposition of organic films, for example, organopolyshirokisan such as hydrolyzate (water-soluble) of dimethylpolyshirokisan, organosilane, organoalkoxysilane, organosilanol and the like are used. .

In addition, the island-in-the-sea structure by phase separation of the acrylic resin 6 and the alkyl acid ester 7 which is a coating film of a film liquid is not formed when pH of a film liquid is 7 or more, and even if it forms, the difference of the boundary surface mutually differs. It is less effective in preventing the bulging of aluminum.

For this reason, the film liquid should be acidic, and more preferably, the pH value is 4.0 or less. In general, the pH value of the acrylic emulsion zone is acidic and the alginic acid compound is stable in acidic acid because of the presence of additives or free acids for the purpose of emulsifying the emulsion zone. Although many of these become 4.0 or less, when pH value is high, it is preferable to adjust so that pH may be 4.0 or less using organic acids, such as acetic acid and a fish acid, or inorganic acids, such as nitric acid, sulfuric acid, and phosphoric acid.

In addition, although the alginic acid ester was used as a polysaccharide added to an acryl emulsion zone in the above-mentioned Example, even if sodium alginate, amine alginate, etc. were used, the favorable result was obtained. In addition to the alginic acid compound, the same effects can be obtained by using natural effluents such as carboxymethyl cellulose and hydrokishiethyl cellulose or water-soluble polymers of the compounds.

In general, the emulsion zone is often used by adding a reversible agent, but also in the present invention, a reversible agent, a thickener, and the like may be added to the film liquid, and an emulsion zone having a different form may be mixed. You may use it.

As described above, when the monolayer is formed on the organic film by polysaccharides separated into the islands, and the metal deposition film is formed, the gap formed in the monolayer becomes a gas outlet when the organic film is decomposed. In this case, a metal thin film having good light reflectance can be formed.

In addition, since the film is not formed in the vicinity of the minimum film forming temperature of the emulsion zone as in the case of adding a conventional PVA compound to prevent swelling by using a gap formed in the organic film, the film forming temperature range is It is wide and has the advantage that the temperature control width becomes ± 5 ° C which is wider than the conventional ± 1 ° C.

Furthermore, since the amount of water-soluble resin that is more difficult to thermally decompose than an acrylic emulsion such as PVA is lower than that of the conventional organic film, the organic film is easily decomposed, and the residual ratio of undecomposed matter is reduced, so that the luminance of the fluorescent surface as a cathode ray tube is the same as that of the conventional one. It is about 5% higher than the other ones.

Next, the case where the composition liquid which contains acrylic emulsion zone as a main component and adds 0.05-5.0 weight% of polyacrylic acid or polyacrylic acid salt which is incompatible is used as a film liquid used for formation of an organic film, Acryl which is a main component The addition of polyacrylic acid (including polymethacrylic acid) or polyacrylic acid salt (including polyacrylic acid), which is poorly compatible with resin, forms small speckle-shaped recesses in the organic film film formed as in the case where the aforementioned polysaccharide is added. . For this reason, this recessed portion forms a pinhole or ring-shaped hole on the metal deposition film when the metal deposition film is formed, and this hole becomes a hole through which organic decomposition gas generated by heating escapes. Damage can be prevented.

In this case, when the amount of polyacrylic acid or polyacrylic acid added is large, it increases in the pinholes in the metal deposition film, thereby reducing the light reflectance of the metal deposition film and reducing the luminous efficiency of the phosphor. In addition, if the addition amount is small, it is natural, but the number of pinholes on the metal deposition film is reduced, and the discharge of organic decomposition gas is insufficient, resulting in an unpleasant phenomenon such as swelling of the metal deposition film. Therefore, the amount of acrylic acid or acrylate added is preferably 0.05-5.0% by weight.

According to such a method, it is possible to reliably prevent swelling or breakage of the metal deposition film without using conventional additives such as H ₂ O ₂ and inorganic substances.

Moreover, as a salt of polyacrylate, the alkali salt using alkali metal, such as sodium, potassium, calcium, or alkaline-earth metal, ammonium, etc. is suitable.

On the other hand, as an aqueous emulsion mainly composed of an acrylic resin for forming a smooth resin film, a resin of a polymer or copolymer which is a combination of acrylate type monomers such as acrylic acid ester, methacrylic acid ester, acrylic acid, methacrylic acid, and other acrylic styrene The emulsion zone which is a copolymer with acrylonitrile resin, styrene, acryl resin, etc. is suitable from the viewpoint of film smoothness and thermal decomposition property.

Example 2

First, as shown in the main cross-sectional view of FIG. 1, a phosphor layer 3 formed of phosphor particles 2 of red, blue, and green colors is formed on the inner surface of the face plate. Known techniques such as the method used and the method of directly attaching the phosphor powder to the adhesive film can be used.

Next, a film solution of pH 3.0 to 4.0 having the following composition is applied and dried on the phosphor layer 3 to form an organic film 4, and then an aluminum deposition film 5 is formed.

In applying the film liquid of the above composition, as shown in FIG. 2, the face plate 1 in which the phosphor layer 3 was formed is made to face upward, and the film liquid 11 formed as above is inject | poured.

Subsequently, the face plate 1 is slowly rotated to open the film liquid 11 over the entire inner surface thereof, and as shown in FIG. 3, the face plate 1 is tilted to discharge the overflowed film liquid 11. Subsequently, the face plate 1 is rotated at a high speed to make the coating state of the film liquid 11 uniform, and then heated and dried to form the organic film 4. At this time, the acrylic emulsion particles become the most closely packed state by the water vapor deposition between the individual acrylic resin particles in the film liquid 11, and at the same time, the particles fuse with each other by heat to form a uniform continuum. The organic film 4 is formed. On the other hand, if the acrylic resin contains water-soluble polymers such as polyacrylates, these water-soluble polymers have poor compatibility with acrylic resins. Therefore, the water-soluble polymers are fused with acrylic particles or remain between the particles while being heated and dried during the heat drying process. It moves with water without work to form aggregates of water-soluble polymers.

Therefore, in the organic film 4 after drying, as shown in FIG. 4, the acrylic resin 6 and sodium polyacrylate 7 are separated to form a spot-like island-in-the-sea structure. Here, since the usability is poor at the boundary between the sodium polyacrylate (7) and the acrylic resin (6) separated by the islands-in-law structure, as shown in FIG.

Therefore, the next time the aluminum film is deposited on the organic film 4 to form the aluminum deposition film 5, the gap 5a is formed between the aluminum deposition film 5 and the recessed monolayer portion, and then the organic film is heated by heating. In the step of thermally decomposing (4), the decomposition gas does not escape at this interval 5a to push up the aluminum deposition film 5, and in this case, the smoothness and light reflectance of the aluminum deposition film 5 are eliminated. Since there is little fall, a fluorescent surface with high brightness can be obtained. In this case, the luminous efficiency of the fluorescent surface could be improved by about 5% compared with the conventional one.

Example 3

Perform the same method as in Example 2, but combines the film solution in the following composition.

In this case, when the film solution has a pH value of 3.5 and the film solution is applied to the inner surface of the face plate on which the phosphor layer is formed by the same means as in Example 2 described above to complete the color water pipe, swelling and breakage of the aluminum deposition film occurs. Induction was about twice that of the conventional method, and the brightness was also improved by about 5%.

Example 4

Perform the same method as in Example 1, but combines the film liquid in the following composition.

In this case, the pH value of the film liquid is 3.5. When the film liquid is applied to the inner surface of the face plate on which the phosphor layer is formed by the same means as in Example 1 described above to complete the color water pipe, a smooth organic film is formed. The brightness of the fluorescent screen having a brightness of about 3.5% brighter than that of the prior art was obtained.

In addition, in the above-described embodiment, the shape and size of the gap 5a to prevent swelling of the aluminum deposition film 5 and to allow the decomposition gas to be discharged are determined according to the amount of acrylic resin to be thermally decomposed and the amount of gas generated per unit time. There is a number. That is, the shape and size of the gap 5a due to the island-in-the-sea structure are related to the moving speed and the moving time of the water-soluble polymer during drying as described above.

Since this generally depends on the compatibility of the acrylic resin and the water-soluble molecule, the molecular weight, the drying rate, and the thickness of the applied film, it is possible to prevent the swelling of the aluminum deposition film 5 by the combination of the acrylic resin with various acrylates. The concentration of acrylic acid can vary. The difference in compatibility between the acrylic resin and acrylic acid or its salts varies depending on the type of the copolymer or alkyl group of the acrylic resin, and the acrylic acid varies depending on the salt and the molecular weight.

Therefore, as a film composition necessary for improving the smoothness of the organic film 4 and preventing swelling of the aluminum deposition film 5, the resin amount of the acrylic emulsion is 10-30% by weight, and the water-soluble polymer with acrylic acid and its salt is 0.05-5.0 Weight percent is suitable.

In particular, when the concentration of the water-soluble polymer is high, it is necessary to clean the side wall of the face plate, in which case it does not fall off after washing with water, and it takes a long time to dry, and furthermore, it is difficult to uniformly apply the film liquid to the inner surface of the face plate. Since it is difficult to make the polyacrylic acid or salt thereof, the concentration of polyacrylic acid or its salt is preferably lower, and the concentration range is 0.05-1.0 wt%.

In addition, the above-mentioned film liquid does not cause phase separation when its pH value is 7.0 or more, so that even if the tissue is not formed or the difference in the interface between each other becomes small, the swelling of the aluminum deposition film 5 is prevented. Become ineffective. This is attributable to the fact that the acrylic particles of the acrylic emulsion swell with alkalinity and have good compatibility with acrylic acid or its salts.

For this reason, the film liquid preferably has a pH value of 4.0 or less, more preferably acidic. Generally, the pH value of the acrylic emulsion zone is acidic due to the presence of an additive or free acid for the purpose of preservation of the acrylic emulsion zone. For this reason, even if special adjustment of a film liquid is not carried out, pH value may become 4.0 or less in many cases. However, when this pH value is high, it is preferable to adjust so that pH may be 4.0 or less using organic acid or inorganic acid, such as acetic acid and a hydroxyl acid.

In this case, however, the addition of a large amount of inorganic acid may dissolve the phosphor and cause a decrease in the phosphor emission luminance. Therefore, it is preferable to add a small amount or adjust the pH value using an organic acid. In general, the emulsion zone is often used by adding a reversible agent, but also in the above examples, a reversible agent, a thickener, and the like may be added to the film liquid, and it may be said that the emulsion zone may be mixed and used. none.

As described above, when a water-soluble polyacrylic acid or a salt thereof is used as an additive, when a monolayer is formed on the film by the additive to form a metal deposition film, as in Example 1, the gap formed in the monolayer is caused by organic film decomposition. Since the gas is an outlet of the generated gas, it is possible to form a metal thin film having good light reflectivity without causing swelling or breakage. In addition, since the amount of water-soluble resins that are less difficult to thermally decompose than acrylic emulsions, such as inorganic materials such as silicate or colloidal silica, organic films are easier to decompose, and the residual ratio of undecomposed products is less. The brightness of the light source is about 5% higher than that of the conventional art.

Claims (9)

A method of forming a cathode ray tube fluorescent surface in which a phosphor layer, an organic film, and a metal reflective film are sequentially formed on an inner surface of a face plate, and the metal reflective film is brought into close contact with the phosphor layer by heating the face plate to decompose and remove the organic film. The organic film is formed by applying an acrylic resin emulsion zone as a main component to a phosphor layer on the inner surface of a face plate and applying a film solution containing a large amount of an additive having poor compatibility with the acrylic resin, followed by drying. Method of formation. The method according to claim 1, wherein the additive is a water-soluble polysaccharide having a 6-membered ring of 0.01-1.0% by weight or a compound thereof. The method according to claim 1, wherein the additive is a water-soluble polysaccharide having a 6-membered ring of 0.01-10% by weight, or a compound thereof and 0.01-10% by weight of an organosilicon compound, based on an acrylic resin emulsion zone. . The method according to claim 2 or 3, wherein the polysaccharide is cellulose or a compound thereof. The method according to claim 2 or 3, wherein the polysaccharide is an alginic acid compound. The method according to claim 1, wherein the film liquid has a pH value of 4.0 or less. The method according to claim 1, wherein the additive contains polyacrylic acid comprising water-soluble polymethacrylic acid or acrylate salt comprising polymethacrylic acid salt. The method according to claim 7, wherein the water-soluble polyacrylic acid or polyacrylic acid salt is contained in an amount of 0.05 to 5.0% by weight as an additive of the film liquid. 8. The method according to claim 7, wherein the film liquid has a pH value of 4.0 or less.

Images