JPS6337534A - Formation of phosphor screen - Google Patents

Abstract

PURPOSE:To aim at improvement in bond strength, by possessing a forming process of a phosphor screen sticking powder inclusive of a phosphor to the adhesive coat formed on a substrate, and a phosphor screen's bond strengthing process washing this phosphor screen with an aqueous solution containing alkali salt silicate and a surface active agent. CONSTITUTION:An adhesive coat 2 is formed on a substrate 1, using a photomask having the specified stripe pattern, for example, the specified position forming a phosphor stripe layer 5R of red emission is exposed to light, making the coat 2 contact with wet air, and an exposed part is altered to a layer 3 having tackiness, powder 4 of a phosphor of the red emission is fed onto the substrate 1, processing takes place, thereby forming the phosphor stripe layer 5R of the red emission. Likewise, a phosphor strip layer 5G of green emission and another phosphor stripe layer 5B of blue emission both are formed, whereby a phosphor screen 5 for a color cathode-ray tube is formed. Next, the phosphor screen 5 is washed with an aqueous solution of potassium silicate 1.0 wt% and polyoxyethylene alkyl phenol ether 0.05 wt% of a nonionic surfactant. With this constitution, such a phosphor screen that is extremely high in bond strength is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) This invention relates to a method for forming a phosphor screen of a cathode ray tube, and particularly to a method for improving the adhesion strength of a phosphor screen.

One method of forming a phosphor screen in a long-skinned direct cathode ray tube is to attach a phosphor using an adhesive substance, an example of which is disclosed in Japanese Patent Publication No. 57-20851.

This method will be specifically explained below.

First, a photoadhesive composition that becomes sticky upon exposure to light, such as a mixture of aromatic diazonium salt and polyvinyl alcohol, is uniformly applied to the inner surface of the face panel to form a thin layer of the photoadhesive composition.

Then, a desired portion of this thin layer is selectively exposed to light to develop adhesion, and then, for example, a red-emitting phosphor is supplied as a first color.

Further, the red-emitting phosphor attached to the unexposed portion is developed by air blowing or the like to form a red-emitting phosphor layer.

Thereafter, by repeating the same steps, green and blue light emitting phosphor layers are formed using green and blue light emitting phosphors to form a phosphor screen for a color cathode ray tube.

This method of forming a phosphor screen has the advantage of being able to form a phosphor screen through an extremely simple process compared to the method of making each color phosphor into a photosensitive slurry and repeating sequential application, exposure, and development. There is.

However, the phosphor screen formed by this method is easily peeled off when washed with water or the like before proceeding to the subsequent process, so it is necessary to strengthen the adhesion.

On the other hand, an example of a method for strengthening the adhesion of fluorescent screens is disclosed in Japanese Patent Application Laid-Open No. 56-48
As disclosed in Japanese Patent No. 032, it is known that after a phosphor screen is formed, it is washed with an aqueous solution containing a polymer flocculant and a surfactant to densely fill it with phosphor particles.

B (゛　　　.

However, in the above method for forming a phosphor screen, the phosphor screen often peels off locally due to washing with water, and the problem of adhesion strength has not been completely solved, and an improvement has been desired.

Therefore, an object of the present invention is to obtain a phosphor screen with high adhesion strength, and to provide a new and improved method for forming a phosphor screen.

B -
In order to achieve the above object, the present invention is characterized in that after the phosphor screen is formed, it is washed with an aqueous solution containing an alkali silicate salt and a surfactant. Here, various alkali silicate salts can be mentioned, and particularly preferred substances are sodium silicate and potassium silicate. Further, as for the surfactant, a substance that significantly lowers the surface tension of the aqueous alkali silicate salt solution is preferable.

According to the present invention, the alkali silicate is interposed between the particles of the phosphor and between the substrate and the phosphor, and the alkali silicate is interposed between the particles of the phosphor and the substrate and the phosphor, and the silicate is interposed between the phosphor particles and the phosphor to increase the mutual bonding strength between them through chemical bonds such as siloxane bonds. Contributes to improving adhesion strength. In addition, the surfactant increases the permeability of the treatment liquid and prevents the occurrence of local unevenness.

Hereinafter, the method for forming a fluorescent screen according to the present invention will be explained in detail using Examples.

First, as shown in FIG. 1(a), an aqueous solution of a mixture of aromatic diazonium zinc chloride double salt and polyvinyl alcohol is applied onto the substrate (1), which is the face panel, by a spin code method, dried, and exposed to light. An adhesive coating (2) consisting of a thin layer of adhesive composition is formed.

Next, as shown in FIG. 1(b), a photomask having a predetermined stripe pattern is used to expose a predetermined position where a red emitting phosphor stripe layer (5R) will be formed as the first color. , by contacting the coating (2) with moist air, the exposed areas are transformed into a sticky layer (3). Next, as shown in FIG. 1(C), the substrate (1) is
A red-emitting phosphor powder (4) is supplied on top of the adhesive layer (3) in a desired area, and red-emitting phosphor powder present in an unexposed area in an undesired area. The body (4) is developed by air blowing, and as shown in FIG. 1(d), a red-emitting phosphor stripe layer (
5R).

Hereinafter, by repeating the same procedure as shown in FIG. 1(e), a green-emitting phosphor stripe layer (5G) is formed.
, a blue-emitting phosphor stripe layer (5B) is formed, and a phosphor screen (5) for a color cathode ray tube is formed.

Next, as shown in FIG. 1(f), potassium silicate 1.
The fluorescent screen (5) is cleaned with an aqueous solution of 0% by weight and 0.05% by weight of polyoxyethylene alkylphenol ether, a nonionic surfactant. Here, regarding the concentration of potassium silicate, if it is too low than 0.5% by weight, it will not be effective, and if it exceeds 3.0% by weight, potassium ions will remain and the quality of the phosphor screen will deteriorate significantly. 0.5
It is desirable to set it within the range of ~3.0% by weight. on the other hand,
Regarding the concentration of nonionic surfactant, if it is too low, the permeability of the treatment liquid will be poor (local unevenness is likely to occur), and if it is too high, the viscosity will be high (and difficult to handle.
．． 02 to 1.0% by weight is desirable. Note that these desirable ranges vary depending on the materials used, and may be appropriately set depending on the combination.

Next, approximately 2.0 kg/cm was applied from a nozzle to the phosphor screen subjected to such treatment, the phosphor screen treated with a conventional aqueous solution containing a polymer flocculant and a surfactant, and the untreated phosphor screen.
Pure water was supplied at a pressure of m2, and the adhesion strength of the phosphor screen was measured.

At this time, the distance between the nozzle tip and the phosphor screen was approximately 3.0 cm. Thereafter, when the fluorescent screen was observed, the results shown in Table 1 were obtained.

As is clear from Table 1, it was confirmed that the phosphor screen produced by the method of the present invention has extremely high adhesion strength compared to the conventional phosphor screen.

As another example, a phosphor screen (5) for a color cathode ray tube is formed in the same manner as in the first example.

Next, as shown in FIG. 1(f), sodium silicate 1.
The fluorescent screen (5% by weight
).

Here, regarding the concentration of sodium silicate, if it is too low, there will be no effect, and if it is too high, sodium ions will remain and the quality of the phosphor screen will be significantly deteriorated.
~3.0% by weight is desirable. On the other hand, regarding the concentration of anionic surfactant, if it is too low, the permeability of the treatment liquid will be poor and local unevenness will easily occur, and if it is too high, the viscosity will become high and it will be difficult to handle. .5% by weight is desirable.

Next, approximately 2.0 kg/kg of water was applied from a nozzle to the phosphor screen that had undergone such treatment, the phosphor screen that had been treated with a conventional aqueous solution containing a polymer flocculant and a surfactant, and the untreated phosphor screen.
Pure water was supplied at pressures c and z, and the adhesion strength of the phosphor screen was measured. At this time, the distance between the nozzle tip and the phosphor screen was approximately 3.0 cm.

Thereafter, when the fluorescent screen was observed, the results shown in Table 2 were obtained.

As shown in Table 2, the phosphor screen produced by the method of the present invention has 0
．． Although about 8% peeling occurred, it is clear that the adhesion strength is significantly higher than that of conventional phosphor screens.

As yet another example, a phosphor screen (5) for a color cathode ray tube is formed in the same manner as the example shown in Table 1 above.

Next, as shown in FIG. 1(f), potassium silicate 1.
0% by weight, 2.0% by weight of sodium silicate and 0% polyoxyethylene alkyl ether of nonionic surfactant.
．． The phosphor screen (5) is cleaned with an aqueous solution containing 5% electric charge.

Here, the concentration of the treatment liquid is preferably within the concentration range shown in the first and second embodiments.

Next, approximately 2.0 kg/cm was applied from a nozzle to the phosphor screen subjected to such treatment, the phosphor screen treated with a conventional aqueous solution containing a polymer flocculant and a surfactant, and the untreated phosphor screen.
Pure water was supplied at a pressure of m2, and the adhesion strength of the phosphor screen was measured.

At this time, the distance between the nozzle tip and the phosphor screen was approximately 3.0 cs.

Thereafter, when the fluorescent screen was observed, the results shown in Table 3 were obtained.

It is clear that a treatment solution containing a mixture of a plurality of types of alkali silicate salts as in this example is also effective in improving the adhesion strength of the phosphor screen.

In the examples, a phosphor screen consisting of red, green, and blue emitting phosphor stripes has been described, but the present invention is not limited to this, and the phosphor can be attached using an adhesive substance. A formed fluorescent screen for a monochrome cathode ray tube may also be used.

As explained above, the method for forming a phosphor screen of the present invention has great practical effects because it can provide a phosphor screen with significantly higher adhesion strength than conventional methods.

[Brief explanation of the drawing]

FIGS. 1A to 1F are side sectional views of main parts in each step of an embodiment of the present invention. (1)... Substrate, (2)... Adhesive film, (4)... Powder, (5)... Fluorescent screen, (6)... Cleaning treatment liquid.

Claims (1)

[Claims] A step of forming a phosphor screen in which powder containing a phosphor is attached to an adhesive film formed on a substrate, and a step of strengthening the adhesion of the phosphor screen in which the phosphor screen is cleaned with an aqueous solution containing an alkali silicate salt and a surfactant. A method for forming a phosphor screen, comprising: