JPH07226155A - Fluorescent screen forming method for color picture tube - Google Patents

Abstract

PURPOSE:To reduce work manhours, and reduce consumptive materials by performing exposure development through a shadow mask, leaving an exposure part, and forming respective picture elements after continuously applying/drying first and second suspension to/on a panel inside surface with every color. CONSTITUTION:Suspension is composed of polyvinyl alcohol, bichromate, water and solid particles, and respective colors of G, B and R are made different from each other by the solid particles, and second suspension is made higher in a polymerization degree of polyvinyl alcohol than first suspension. The first suspension of a first color G is applied to and dried on an inside surface of a panel 1 of an image receiving tube, and a first layer 13G is formed. In succession, the second suspension of the same color is applied and dried, a second layer 14G is formed. A shadow mask is adjusted to a position to a fluorescent screen of the first color, and is exposed, and development processing is performed by hot pure water, and insoluble part becomes a picture element 15G of the first color. Similar processing is performed on a second color B and a third color R, and respective picture elements 15B and 15R are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a fluorescent surface in a color picture tube, and particularly when forming each picture element having a two-layer structure, a minimum exposure step and a development step are required. The present invention relates to a method for forming a fluorescent surface in a sufficient color picture tube.

[0002]

2. Description of the Related Art Conventionally, in order to improve the filling degree of the fluorescent film on the fluorescent surface of a color picture tube and obtain a fine-pitch type fluorescent film, it is suspended twice for each color. It is known to apply a suspension to form a pixel having a two-layer structure.

In a known color picture tube having such a structure, when a fluorescent surface is formed on the inner surface of the panel by coating,
In advance, a suspension of a first color composed of polyvinyl alcohol, dichromate, water and solid particles of a first color, and a second color of the composition in which only the color of the solid particles is different. And the suspension of the third color are separately prepared. First, the suspension of the first color is applied to the inner surface of the panel of the color picture tube, and then the application portion is applied. After drying, exposure is performed through a shadow mask to insolubilize the exposed portion, followed by development with warm water to form a pixel of the first layer consisting of only the insolubilized portion. next,
If the application of the suspension of the first color, the drying of the applied portion, the exposure through the shadow mask, and the development with hot water are sequentially performed on the picture elements of the first layer, the picture of the first layer is drawn. The second-layer picture element laminated on the element is formed, and a first-color picture element having a configuration in which the second picture element is laminated on the first-layer picture element is obtained.

Further, when forming the picture element of the second color and when forming the picture element of the third color, the same steps as those for forming the picture element of the first color are performed. For example, first, by using the suspension of the second color, on the inner surface of the panel of the color picture tube,
By forming a second color picture element in which a second picture element is laminated on the first picture element, and then using the third color suspension, the inner surface of the panel of the color picture tube is formed. In the same manner, if a third color picture element in which the second picture element is laminated on the first picture element is formed, a second picture element is formed on the first picture element for each color.
No. 58-212034 discloses an example of a method for forming a fluorescent surface in such a color picture tube, which is capable of obtaining a picture element having a structure in which the picture elements are laminated.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the fluorescent surface forming method disclosed in No. 2034, although it is possible to obtain a picture element having a high degree of phosphor particle packing for each color, when a picture element of one color is formed, Installation with alignment of the shadow mask twice,
It is necessary to go through the steps of two exposures, two shadow mask removals, and two developments.
Since it is the same when constructing the picture elements of the other two colors,
Installation, exposure with alignment of the shadow mask,
The steps of removing the shadow mask and developing must be repeated six times for convenience.

As described above, in the known method for forming a fluorescent surface, the number of working steps for forming the fluorescent surface in the color picture tube is increased, the consumption of the developing solution is increased, and it is uneconomical. There is.

The present invention eliminates the above-mentioned problems, and an object of the present invention is to reduce the number of working steps when forming a fluorescent surface having a high degree of filling of dye particles and to save consumption materials. Another object of the present invention is to provide a method for forming a fluorescent surface in a color picture tube.

[0008]

In order to achieve the above object, the present invention comprises means for forming a fluorescent surface on the inner surface of the panel through the following steps.

1. A first suspension of a first color comprising each composition of polyvinyl alcohol, dichromate, water and solid particles of a first color, and a second suspension of the composition wherein only the color of the solid particles is different. 1. forming a first suspension of color and a first suspension of third color, respectively; A second suspension of the first color composed of each composition of polyvinyl alcohol having a higher degree of polymerization than the polyvinyl alcohol, dichromate, water and the solid particles of the first color, and
2. forming a second suspension of a second color and a second suspension of a third color in the composition, which differ only in the color of the solid particles; 3. A step of applying the first suspension of the first color to the inner surface of the panel of the color picture tube and drying the same to form a first layer of the first color. 4. A step of applying the second suspension of the first color on the first layer of the first color and drying the second suspension to form a second layer of the first color in a laminated manner. 5. a step of exposing the laminated first layer of the first color and the second layer of the first color through a shadow mask to insolubilize the exposed portion; 6. Developing with warm water to leave only the insolubilized portion and form each picture element of the first color on the inner surface of the panel of the color picture tube. Subsequently, the same steps 3 to 6 as those performed for the first color are performed on the panel inner surface of the color picture tube for the second color, and the second step is performed on the panel inner surface of the color picture tube.
7. Forming each picture element of color Further, on the inner surface of the panel of the color picture tube, the same steps 3 to 6 as those performed for the first color are carried out for the third color, and the inner surface of the panel of the color picture tube is provided with the respective picture elements of the third color. Forming step.

[0010]

According to the above-mentioned means, the first suspension of the first color, which comprises each composition of polyvinyl alcohol, dichromate, water and the solid particles of the first color, and the solid particles in the composition A first suspension of a second color and a first suspension of a third color that differ only in the colors of, respectively, and a polyvinyl alcohol and a dichromate having a higher degree of polymerization than the polyvinyl alcohol. , A second suspension of a first color consisting of water and each composition of the solid particles of the first color, and a second suspension of a second color that differs only in the color of the solid particles in the composition. Suspension,
A second suspension of the third color is prepared for each, and subsequently,
For each color, the first suspension is applied to the inner surface of the panel of the color picture tube in sequence and dried to form a fluorescent film of the first layer, and then the first layer is exposed and developed. Without applying the second suspension on the fluorescent film of the first layer,
The fluorescent film of the second layer is dried to form a laminated film, and the laminated fluorescent film of the first layer and the second layer is subjected to exposure using a shadow mask and subsequent development to obtain each color of each color. The picture elements are arranged in sequence.

In this case, the first layer forming the first layer of the fluorescent film is formed.
The degree of polymerization of polyvinyl alcohol forming the second layer of the fluorescent film is selected to be higher than the degree of polymerization of polyvinyl alcohol of the suspension of 1. Due to the fogging, the underlying fluorescent film of the first layer is not dissolved, and when developing the fluorescent films of the first layer and the second layer formed in layers, it is insolubilized by exposure. The formed second layer of the fluorescent film acts as a protective layer of the underlying first layer of the fluorescent film, and the first layer of the fluorescent film is not dissolved by the developing solution.

As described above, according to the above-mentioned means, the exposure process using the shadow mask for each color and the subsequent development process are performed only once for each color, as compared with the known method for forming a fluorescent surface in a color image receiver. Even so, since it is possible to form a fluorescent surface that is almost the same as the fluorescent surface having a known high degree of packing of fluorescent particles, it is possible to reduce the number of working steps accordingly, and, It is possible to reduce consumption of materials for development and the like.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing the outline of the construction of an embodiment of a color picture tube having a fluorescent surface formed by the method for forming a fluorescent surface according to the present invention.

In FIG. 1, 1 is a panel part, 2 is a funnel part, 3 is a neck part, 4 is a fluorescent surface, 5 is a shadow mask, 6 is a magnetic shield, 7 is a deflection yoke, 8 is a purity adjusting magnet, and 9 is a magnet. Is a center beam static convergence adjustment magnet, 10 is a side beam static convergence adjustment magnet, 11 is an electron gun, and 12 is an electron beam.

The tube body which constitutes the color picture tube is
It comprises a panel section 1 arranged on the front side, a neck section 3 accommodating the electron gun 11, and a funnel section 2 arranged between the panel section 1 and the neck section 3. Panel part 1
Has a fluorescent surface 4 arranged and formed on its inner surface.
A shadow mask 5 is arranged so as to face the. Panel part 1
The magnetic shield 6 is disposed inside the coupling portion of the funnel portion 2 and the deflection yoke 7 is disposed outside the coupling portion of the funnel portion 2 and the neck portion 3. On the outside of the neck 3,
A purity adjusting magnet 8, a center beam static convergence adjusting magnet 9 and a side beam static convergence adjusting magnet 10 are arranged side by side, and the three electron beams 12 projected from the electron gun 11 are directed in a predetermined direction by the deflection yoke 7. After being deflected, it is configured to reach the corresponding color picture element on the fluorescent surface 4 through the shadow mask 5.

In this case, the image display operation in the color picture tube having the above-mentioned structure is the same as the image display operation in the known color picture tube, and therefore the description of the image display operation in this color picture tube is omitted.

Next, FIG. 2 is an enlarged sectional view showing a very small part of the fluorescent surface 4 in the color picture tube shown in FIG. 1. FIG. FIG. 6B is a cross-sectional configuration diagram of the one being formed, and FIG. 6B is a cross-sectional configuration diagram of the one where the formation of the fluorescent surface 4 is completed.

In FIGS. 2A and 2B, 13G is the first layer of the first color (green), 13B is the first layer of the second color (blue),
13R is the first layer of the third color (red), 14G is the first layer (green)
Second layer, 14B is the second layer of the second color (blue), 14R is the second layer of the third color (red), and 15G is the pixel of the first color (green), 1
5B is a second color (blue) picture element, 15R is a third color (red) picture element, and other same constituent elements as those shown in FIG. 1 are denoted by the same reference numerals.

Then, as shown in FIG. 2B, on the inner surface of the front panel of the color picture tube, the second layer of the first color (green) is formed on the first layer 13G of the first color (green). The layer 14G is laminated to form the first color (green) picture element 15G, and the second color (blue) second layer 14 is provided on the second color (blue) first layer 13B.
B is laminated to form a second color (blue) picture element 15B, and a third color (red) second layer 14R is laminated on the third color (red) first layer 13R. Third color (red) picture element 15
R is constructed. In this case, the first color (green) picture element 15
G, second color (blue) picture element 15B, third color (red) picture element 1
5R has a striped shape or a circular shape similar to the fluorescent surface of a known color picture tube, and is arranged in the same manner as the known arrangement.

Now, the means for forming the fluorescent surface 4 having the above-mentioned structure will be described.

First, in order to form the first layer 13G of the first color (green), a first suspension of the first color (green) having the following composition is prepared.

Green luminescent phosphor particles 10.0 wt% Polystyrene emulsion (solid content) 0.7 wt% Kuraray Poval 205 2.3 wt% Ammonium dichromate 0.23 wt% Surfactant 0.02 wt% Residual water Next, the temperature of this first suspension is adjusted and set to 25 ° C., and the first suspension is applied to the inner surface of the front panel of the color picture tube while rotating this panel. And the first
The portion coated with the suspension of is dried at a temperature of 48 ° C. to form the first layer 13G of the first color (green).

In order to form the second layer 14G of the first color (green), the first color (green) having the following composition is formed.
Make a second suspension of.

Green luminescent phosphor particles 25.0% by weight Polystyrene emulsion (solid content) 0.7% by weight Kuraray Poval 224 2.3% by weight Ammonium dichromate 0.23% by weight Surfactant 0.02% by weight Water Residue Subsequently, the temperature of this second suspension was adjusted and set to 25 ° C., and the second suspension was rotated on the formed first layer (G) of the first color (green) while rotating the panel. Apply the suspension. Then, the portion coated with the second suspension is dried at a temperature of 48 ° C., and as shown in FIG. 2A, the first color (green) is formed on the first layer 13G of the first color (green). Second layer 14 of green)
A first color (green) fluorescent film in which G is laminated is formed.

Next, a shadow mask is attached to the inner surface of the front panel of the color picture tube having the fluorescent film of the first color (green) by aligning it with the fluorescent film of the first color (green). Then, ultraviolet rays are irradiated through the shadow mask to partially expose the fluorescent film of the first color (green) to insolubilize the exposed portion. Next, the exposed first color (green) fluorescent film is developed using warm pure water having a temperature of 40 ° C., and only the insolubilized portion is left and the rest is removed by dissolution. At this time, the remaining insolubilized portion is the first color (green) picture element 15G in which the first color (green) second layer 14G is laminated on the first color (green) first layer 13G. It is what is formed.

Subsequently, the first layer 13B of the second color (blue)
In order to form, a first suspension of a second color (blue) having the following composition is prepared.

Blue light-emitting phosphor particles 10.0% by weight Polystyrene emulsion (solid content) 0.7% by weight Kuraray Poval 205 2.3% by weight Ammonium dichromate 0.23% by weight Surfactant 0.02% by weight Water Residue The temperature of the first suspension of this second color (blue) is then raised to 25
Adjusted and set to ℃, from the top of the first color (green) picture element 15G formed, while rotating the panel, the second color (blue)
Of the second color (blue), and then the portion coated with the second suspension of the second color (blue) is dried at a temperature of 48 ° C. to obtain the first color of the second color (blue). Form layer 13B.

Similarly, in order to form the second layer 14B of the second color (blue), a second suspension of the second color (blue) having the following composition is prepared.

Blue light-emitting phosphor particles 25.0% by weight Polystyrene emulsion (solid content) 0.7% by weight Kuraray Poval 224 2.3% by weight Ammonium dichromate 0.23% by weight Surfactant 0.02% by weight Water Residue The temperature of the second suspension of this second color (blue) is then raised to 25
The temperature is adjusted and set to 0 ° C., and the second suspension of the second color (blue) is applied onto the formed first layer 13B of the second color (blue) while rotating the panel. And this second color (blue)
The portion coated with the second suspension of No. 2 was dried at a temperature of 48 ° C., and the second layer 14B of the second color (blue) was laminated on the first layer 13B of the second color (blue). A two-color (blue) fluorescent film is formed.

Then, as before, a shadow mask is aligned with the second color (blue) fluorescent film on the inner surface of the front panel of the color picture tube having the second color (blue) fluorescent film. Then, it is attached, and ultraviolet rays are radiated through the shadow mask to partially expose the fluorescent film of the second color (blue) to insolubilize the exposed portion. Next, temperature 40 ℃
The exposed fluorescent film of the second color (blue) is developed using the warm pure water described above to leave only the insolubilized portion and dissolve and remove the rest. At this time, the remaining insolubilized portion is the second layer 14 of the second color (blue) on the first layer 13B of the second color (blue).
The second color (blue) picture element 15B in which B is stacked is formed. During the exposure of the second color (blue) fluorescent film, the first color (green) picture element 15G formed portion on the inner surface of the front panel of the color picture tube is not exposed. Since the first color (green) picture element 15G is insolubilized during the above-described first color (green) exposure, it is not dissolved and removed during the development of the second color (blue) fluorescent film. Absent.

Further, subsequently, the third color (red) picture element 15R is formed on the inner surface of the front panel of the color picture tube, and the third color (red) picture element 15R is formed in the first step. Instead of using green-emitting or blue-emitting phosphor particles in forming the three-color (red) first suspension and the third-color (red) second suspension, Except for the fact that red-emitting phosphor particles are used, the first color (green) picture element 1 described above is used.
Since this is exactly the same as the forming process of the 5G and second color (blue) picture elements 15B, detailed description of the forming process of the third color (red) picture element 15R is omitted.

By the way, the first color (green) picture element 15
G, in the process of forming the second color (blue) picture element 15B and the third color (red) picture element 15R, the first to third color first
The Kuraray Poval 205 having a degree of polymerization of 500 used in the suspension of No. 1 has a large water solubility at the set temperature of 25 ° C. of the first suspensions of the first to third colors. When the suspension is applied and dried at a temperature of 48 ° C., a photo-crosslinking reaction occurs between the clarepova 205 and ammonium dichromate, resulting in a decrease in water solubility.

On the other hand, Kuraray Poval 224 having a degree of polymerization of 2400 used in the second suspensions of the first to third colors.
Is highly water-soluble at a set temperature of developing water of 40 ° C., but when a fluorescent film obtained by coating and drying the second suspension of the first to third colors is irradiated with ultraviolet rays through a shadow mask, In the part, a photo-crosslinking reaction between Kuraray Poval 224 and ammonium dichromate occurs, and the water solubility also decreases.

That is, the Kuraray Poval 205 is heated by the heat fog so that the second layers 14G, 1 and 1 of the first to third colors are formed.
At the time of forming 4B and 14R, the second suspension of the first to third colors having the set temperature of 25 ° C. is changed to the first layer 13 of the first to third colors.
Even if it is applied onto G, 13B, and 13R, the first layers 13G, 13B, and 13R of the first to third colors do not melt at the temperature at which they are applied.

The second layer 14 of the first to third colors is also used.
The exposed portions of G, 14B, and 14R serve as protective layers against developing water when the exposed portions are developed, so that the first layers 13G, 13B, and 13R of the first to third colors have a set temperature of 40. It is not dissolved by the developing water at ℃, and remains as it is on the inner surface of the panel of the color picture tube.

On the other hand, the second layer 14 of the first to third colors
The unexposed portions of G, 14B, and 14R are not subjected to the above-mentioned insolubilization treatment, so that the temperature of the unexposed portions is set to the set temperature 4 together with the second layers 13G, 13B, and 13R of the first to third colors underneath.
It is dissolved and removed by developing water at 0 ° C., and as shown in FIG. 2B, the first to third color picture elements 15G, 15B, 1
5R is formed.

In the above-mentioned embodiment, the Kuraray Poval 205 having a degree of polymerization of 500 is used as the first suspension of the first to third colors, and the second suspension of the first to third colors is used. Shows an example of using Kuraray Poval 224 having a degree of polymerization of 2400. The degree of polymerization of Kuraray Poval in the present invention is
The present invention is not limited to the above, and can be changed as appropriate by changing the set temperature in each step. Then, the first to the third with respect to the degree of polymerization of Kuraray Poval used in the first suspension of the first to the third colors.
The degree of polymerization of Kuraray Poval used in the second suspension of color is preferably twice or more in order to facilitate temperature setting in each step.

Further, in the above-mentioned embodiment, an example in which polyvinyl alcohol is used for the first suspension of the first to third colors and the second suspension of the first to third colors is shown. However, the present invention is not limited to those using polyvinyl alcohol, modified polyvinyl alcohol having photochromic properties with dichromate, for example, polyvinyl chloride modified with acrolein, crotonaldehyde, furfural. Alcohol may be used.

Further, in the above-mentioned embodiment, the first suspension liquid of the first to the third colors and the second suspension liquid of the first to the third colors are respectively emitted with the first to the third colors. Although the example of using the fluorescent particles is shown, the present invention is not limited to the use of the fluorescent particles of the first to third colors, and the first color (green) pigment particles ( Cr ₂ O ₃ ), second color (blue) pigment particles (CoAl ₂ O ₄ ) and third color (red) pigment particles (Fe ₂ O ₃ ) may be used, respectively, and the first
To the third color luminescent phosphor particles, the first color (green) pigment particles (Cr ₂ O ₃ ), and the second color (blue) pigment particles (CoAl ₂
O ₄ ), and third color (red) pigment particles (Fe ₂ O ₃ ) may be used in combination.

Further, in the above-described embodiment, the first suspension liquid of the first to third colors and the second suspension liquid of the first to third colors have the same first to third colors, respectively. Although an example of using the phosphor particles is shown, the present invention is not limited to the first to third embodiments.
The first and second color suspensions are not limited to those using the same first to third color luminescent phosphor particles, and the first to third color suspensions are not limited. By using the pigments of the first to third colors in the liquid and using the phosphor particles of the first to third colors in the second suspension of the first to third colors,
As disclosed in JP-A-3-261044, a first layer (pigment layer) of the first to third colors containing pigment particles is formed on the inner surface of the front panel of a color picture tube, and the first layer is formed thereon. First to third containing first to third color luminescent phosphor particles
It is also possible to form a color second layer (fluorescent film) to form a color picture tube with high contrast. In this case, the first color (green) pigment is chromium oxide, cobalt green, the second color (blue) pigment is cobalt aluminate, ultramarine blue, cerian blue, and the third color (red) pigment is iron oxide. , Lead oxide, chrome vermilion, etc. are used.

[0042]

As described above, according to the method for forming a fluorescent surface of the present invention, polyvinyl alcohol, dichromate,
First to third composed of respective compositions of water and solid particles of the first color
Forming and preparing three types of first suspensions of each color, and a first composition comprising polyvinyl alcohol having a polymerization degree higher than that of polyvinyl alcohol, dichromate, water, and solid particles of the first color. To 3 types of second suspensions of the third color are prepared respectively, and the first suspension is applied to and dried on the inner surface of the panel of the color picture tube in sequence for each color. Of the first layer, and then the second suspension is applied onto the first layer of fluorescent film and dried to form a second layer of fluorescent film. First of each color
The first and third color pixels are sequentially formed by performing exposure using a shadow mask and subsequent development on the first and second layer fluorescent films.

In this case, the first fluorescent film forming the first layer is formed.
The degree of polymerization of polyvinyl alcohol in the suspension of
Since the one having a high degree of polymerization of the polyvinyl alcohol forming the fluorescent film of the layer is selected, the fluorescent film of the first layer therebelow is caused by the heat fogging when forming the fluorescent film of the second layer. Does not dissolve, and when developing the fluorescent films of the first and second layers of the respective colors formed in a laminated manner, the fluorescent film of the second layer which has been insolubilized by exposure is formed underneath. Functioning as a protective layer for the first layer of the fluorescent film, and the first layer of the fluorescent film is not dissolved by the developing solution.

As described above, according to the method for forming a fluorescent surface according to the present invention, as compared with the method for forming a fluorescent surface in a known color image receiver, the steps of exposure using a shadow mask and subsequent development are performed for each color. It is possible to form a fluorescent surface almost equivalent to a known fluorescent surface having a high degree of packing of fluorescent particles, even if only once, respectively, and to reduce the number of working steps accordingly. In addition, there is an effect that it is possible to save the consumption material accompanying the development and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing an outline of a configuration of an embodiment of a color picture tube having a fluorescent surface formed by a method for forming a fluorescent surface according to the present invention.

FIG. 2 is a cross-sectional view showing an enlarged part of a fluorescent surface of the color picture tube shown in FIG.

[Explanation of symbols]

1 Panel Part 2 Funnel Part 3 Neck Part 4 Fluorescent Surface 5 Shadow Mask 6 Magnetic Shield 7 Deflection Yoke 8 Purity Adjusting Magnet 9 Center Beam Static Convergence Adjusting Magnet 10 Side Beam Static Convergence Adjusting Magnet 11 Electron Gun 12 Electron Beam 13G No. 1st layer of 1 color (green) 13B 1st layer of 2nd color (blue) 13R 1st layer of 3rd color (red) 14G 2nd layer of 1st color (green) 14B 2nd color (blue) 2nd layer 14R 3rd color (red) 2nd layer 15G 1st color (green) picture element 15B 2nd color (blue) picture element 15R 3rd color (red) picture element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Morishita ▲ Introduction ▼ 1-280, Higashi Koigakubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (5)

[Claims] 1. A method for forming a fluorescent surface in a color picture tube if a fluorescent surface made up of three color fluorescent picture elements is arranged and formed on the inner surface of the panel, and a shadow mask is arranged facing the fluorescent surface. The method for forming a fluorescent surface in a color picture tube according to claim 1, wherein at least one color of the fluorescent picture elements on the fluorescent surface is formed on the inner surface of the panel through the following steps. 1. Polyvinyl alcohol, dichromate, water and 1st
1. forming a first suspension of each composition of colored solid particles; 2. a step of forming a second suspension composed of each composition of polyvinyl alcohol having a higher degree of polymerization than polyvinyl alcohol, dichromate, water, and the solid particles of the first color; 3. The step of applying the first suspension to the inner surface of the panel of the color picture tube and drying it to form the first layer; 4. A step of applying the second suspension on the first layer and drying the second suspension to form a second layer by stacking. 5. a step of exposing the laminated first and second layers through a shadow mask to insolubilize the exposed portion; Developing with warm water to leave only the insolubilized portion and form each pixel on the inner surface of the panel of the color picture tube. 2. A method for forming a fluorescent surface in a color picture tube, wherein a fluorescent surface made up of three color fluorescent picture elements is arranged and formed on the inner surface of the panel, and a shadow mask is arranged facing the fluorescent surface. 2. A method for forming a fluorescent surface in a color picture tube, which comprises forming a fluorescent surface on the inner surface of the panel through the following steps. 1. Polyvinyl alcohol, dichromate, water and 1st
A first suspension of a first color consisting of each composition of colored solid particles,
And a second aspect of the present invention, wherein only the color of the solid particles in the composition is different.
1. forming a first suspension of color and a first suspension of third color, respectively; A second suspension of the first color composed of each composition of polyvinyl alcohol having a higher degree of polymerization than the polyvinyl alcohol, dichromate, water and the solid particles of the first color, and
2. forming a second suspension of a second color and a second suspension of a third color in the composition, which differ only in the color of the solid particles; 3. A step of applying the first suspension of the first color to the inner surface of the panel of the color picture tube and drying the same to form a first layer of the first color. 4. A step of applying the second suspension of the first color on the first layer of the first color and drying the second suspension to form a second layer of the first color in a laminated manner. 5. a step of exposing the laminated first layer of the first color and the second layer of the first color through a shadow mask to insolubilize the exposed portion; 6. Developing with warm water to leave only the insolubilized portion and form each picture element of the first color on the inner surface of the panel of the color picture tube. Subsequently, the same steps 3 to 6 as those performed for the first color are performed on the panel inner surface of the color picture tube for the second color, and the second step is performed on the panel inner surface of the color picture tube.
7. Forming each picture element of color Further, on the inner surface of the panel of the color picture tube, the same steps 3 to 6 as those performed for the first color are carried out for the third color, and the inner surface of the panel of the color picture tube is provided with the respective picture elements of the third color. Forming step. 3. The method for forming a fluorescent surface in a color picture tube according to claim 1, wherein the polyvinyl alcohol comprises a modified polyvinyl alcohol modified with one of acrolein, crotonaldehyde and furfural. 4. The method for forming a fluorescent surface in a color picture tube according to claim 1, wherein the solid particles are fluorescent particles and / or pigment particles. 5. The color picture tube according to claim 1, wherein the degree of polymerization of the polyvinyl alcohol and the degree of polymerization of the polyvinyl alcohol having a higher degree of polymerization have a difference of at least twice or more. Fluorescent surface forming method in.