JPH0521009A - Method of manufacturing color cathode ray tube - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To facilitate the formation of index phosphor patterns and enable mass production of auto-convergence color cathode ray tubes. A film-shaped photosensitive film 13 having a reflective film 12 is deposited on one surface of the color selection electrode 1, and a first exposure 16 is performed on the film-shaped photosensitive film from the other surface of the color selection electrode to form a beam transmission hole. Expose a larger area. Next, the reflective film is removed, and the film-shaped photosensitive film is subjected to a second exposure from the other surface of the color selection electrode through the negative film corresponding to the index phosphor pattern. Next, after developing to form a resist layer, an index phosphor is applied to the entire surface, and reverse development is performed to remove the resist phosphor and the index phosphor on the resist layer to form an index phosphor pattern on the surface of the color selection electrode. Form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a color cathode ray tube.

[0002]

2. Description of the Related Art An auto-convergence color cathode ray tube capable of displaying a high-definition image in a clear color has been proposed. Fig. 5 shows the auto-convergence color cathode ray tube.
As shown in FIG. 5, for example, an eight-shaped index phosphor 2 having vertical portions 2a and inclined portions 2b is arranged in a matrix on the back surface of the color selection electrode 1 in which a large number of thin grid elements 4 are arranged at a predetermined pitch. Then, when the index phosphor pattern 3 is formed and the electron beam is scanned, the light emission signal from the index phosphor 2 is used to automatically perform the convergence adjustment and the linearity adjustment. Even when a shadow mask is used as the color selection electrode, a similar index phosphor pattern is formed.

Conventionally, as the index phosphor pattern 3 for detecting the position of the electron beam, a metal mask having a predetermined shape is superposed on the color selection electrode 1, and a suspension containing a phosphor and a binder is spray-coated. Was formed by that.

[0004]

By the way, when the index phosphor pattern 3 is formed by the above method,
There is a problem in that the phosphors stick out and adhere to the beam transmission hole of the color selection electrode 1, that is, the slit portion in the figure, and the phosphor pattern is shaded and visible. For this reason, improvements have been attempted, such as applying from the back side by suction when applying the spray, but it is not perfect, and there remains a problem as a monitor that needs to display all white. However, since it is not conspicuous as a display dedicated to characters or graphics, it has been put to practical use by this method although it is incomplete.

Therefore, as shown in FIG. 6, after spray coating, it is necessary to scrape off the phosphor attached to the slit portion (the through hole portion in the case of a shadow mask) of the color selection electrode 1 with a brush. Thin grid element 5 that easily vibrates
In the case of the color selection electrode 1 having, the fluorescent substance is likely to fall off, so that the fluorescent substance is firmly adhered by the binder. Further, in order to remove the unnecessary portion of the phosphor until the shadow of the phosphor pattern disappears from the appearance, it is necessary to remove the phosphor far inside the grid element body 5 according to the incident angle of the electron beam. For these reasons, the work of scraping off the unnecessary portions of the phosphor with a brush is time-consuming, and a considerable portion of the work must be done manually. In addition, the grid element body 5 is particularly delicate and is often damaged during the work. Therefore, it has been difficult to mass-produce the auto-convergence color cathode ray tube until now.

In view of the above points, the present invention provides a method for manufacturing a color cathode ray tube which facilitates the formation of index phosphor patterns in an auto-convergence color cathode ray tube and enables mass production.

[0007]

The present invention is directed to a color selection electrode 1
A film-like photosensitive film 13 having a reflective film 12 on one surface 1a
And the color selection electrode 1 for the film-like photosensitive film 13.
The first exposure 16 is performed from the other surface 1b of the beam transmission hole 4
A wider area is exposed, then the reflective film 12 is removed, and a second exposure 18 is performed on the film-shaped photosensitive film 13 from one surface 1a of the color selection electrode 1 through a mask 17 having a predetermined pattern to develop the film. After that, the index phosphor 20 is formed on the portion removed by the development.

[0008]

In the present invention, when the first exposure 16 is performed from the other surface 1b of the color selection electrode 1, the light is reflected by the reflection film 12 and a region wider than the beam transmission hole is formed with respect to the film-shaped photosensitive film 13. Exposed. Then, a second exposure 18 is performed from one surface 1a of the color selection electrode 1 through a mask having a predetermined pattern, that is, a negative mask 17 having an index phosphor pattern, and then development is performed to form a beam transmission hole on the color selection electrode 1. A resist film 19 is formed on the entire surface of the other part except for the unexposed part located inward of the edge of the beam transmission hole, that is, the part corresponding to the index phosphor pattern except for 4.

After development, the index phosphor 2 is used.
By forming 0, that is, by coating the entire surface with the indexing phosphor 20 and performing reverse development to remove the resist film 19 and the phosphor 20 thereon, the beam is transmitted to the surface 1a of the color selection electrode 1. A desired index phosphor pattern 3 is formed in a state of being retracted from the hole 4 by a predetermined distance.
Therefore, the work of removing the fluorescent material in the inner portion from the portion of the beam transmitting hole and the edge portion of the beam transmitting hole becomes unnecessary.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

In this example, first, as shown in FIG. 1A, a large number of thin strip-shaped grid elements 5 are arranged at a predetermined pitch, and slits 4 serving as beam transmission holes are formed between the grid elements 5. The color selection electrode 1 is prepared. Further, the Al reflection film 12 is vapor-deposited on one surface of the base film 11, and the film-shaped photosensitive film 13 is further formed on the Al reflection film 12.
And a protective film 14 are further formed on the dry film (for example, manufactured by Hitachi Chemical Co., Ltd., trade name.
Photoc (PHT-145F-25)) 15 is prepared.

Next, as shown in FIG. 1B, the color selection electrode 1
The dry film 15 from which the protective film 14 has been peeled off is superposed on one surface, that is, the surface 1a facing the electron gun, so that the film-shaped photosensitive film 13 is in contact with the surface 1a. Then, heat treatment is performed at 80 to 100 ° C. for 5 to 10 minutes in an electric furnace to laminate the dry film 15 on the surface 1 a of the color selection electrode 1.

Next, as shown in FIG. 1C, the color selection electrode 1
The first exposure 16 is performed on the film-shaped photosensitive film 3 from the other surface 1b. At this time, light is reflected by the Al film 12, and the film-shaped photosensitive film 13 has a width d wider than the slit width d _1.
Exposed to ₂ .

Next, as shown in FIG. 2D, the Al reflection film 1
After stripping the base film 11 together with 2, the negative mask 1 having a desired image pattern, that is, an index phosphor pattern.
7 is superposed on the film-shaped photosensitive film 13, and second exposure 18 is performed from the negative mask 17 side.

Next, as shown in FIG. 2E, a resist layer 19 is formed by development so that the slit 4 of the color selection electrode 1 and the portion other than the desired index phosphor pattern are hidden. At this time, the resist layer 19 is formed so as to partially extend over the inside of the edge portion of the grid element body 5. Therefore, the pattern width d ₃ on the grid element body 5 is narrower than the width d ₄ of the grid element body 5 in the portion corresponding to the index phosphor pattern in which the resist layer 19 is not formed. For development, for example, dipping in trichloroethane and vibrating,
Try to wash off trichloroethane in a water shower. As a result, the unexposed portion is removed.

Next, as shown in FIG. 2F, the index phosphor 20 is applied to the entire surface by, for example, spraying or brush coating.

The composition of the phosphor coating solution in the case of spray coating is shown below. Composition Phosphor (P-46) 80 g In ₂ O ₃ 20 g Aluminum phosphate 5 ml (Yoneyama Chemical Co., Ltd. product name: Monofix A) Water 95 ml Orotane (surfactant) 0.25 ml

The composition of the phosphor coating solution in the case of applying a brush (sponge) is shown below. Phosphor (P-46) 4 g In ₂ O ₃ 1 g Aluminum phosphate 1.5 ml (trade name: Yoneyama Chemical Co., Ltd .: Monofix A) Water 1.5 ml

However, In ₂ O ₃ is mixed in order to impart conductivity to the phosphor. That is, when the index phosphor pattern is hit by the electron beam during operation of the cathode ray tube, the index phosphor pattern is charged and the orbit of the electron beam may shift. In order to prevent this, conductivity is given to the phosphor to prevent charging.

Next, after performing a drying treatment at 120 ° C. for 30 minutes in an electric furnace, reversal development is performed. That is, the resist layer is decomposed into fine flakes by immersion in methylene chloride to remove the resist layer 18 and the phosphor 19 thereon. As a result of this reversal development, as shown in FIG. 2G, the index phosphor pattern 3 in which the 8-shaped index phosphors 2 shown in FIGS. 5 and 6 are formed in a matrix on the surface of the color selection electrode 1 is formed. obtain. After that, a rinse treatment with a methyl alcohol solution is performed, and the product is dried by air blow to complete the process.

As another example of the dry film, as shown in FIG. 3, a dry film 22 having a film-shaped photosensitive film 13 formed on a base film 21 is superposed on the surface 1a of the color selection electrode 1 (see FIG. 3A). ), Then base film 2
After peeling off 1, the base film 11 having the Al reflection film 12 deposited thereon may be superposed on the film-like photosensitive film 13 (see FIG. 3B). The subsequent steps are shown in FIG.
It is the same as that after C.

According to the above embodiment, the dry film 1
By masking the color selection electrode 1 with the resist layer 19 using 5, it is possible to prevent the phosphor from adhering to unnecessary portions (such as slit portions). In particular, the exposure is performed twice, and the first exposure 16 uses the Al reflection film 12 to expose a width d ₂ wider than the slit width d _1, so that the resist layer 19 is located inside the edge of the grid element body 5. It is formed so as to partially straddle, and adhesion of the edge portion of the grid element body 5 of the index phosphor 20 can be avoided.

Therefore, unnecessary portions (slits, edges of the grid element body, etc.) which have been mostly manually worked as in the conventional art.
It is not necessary to scrape off the index phosphor attached to the. Further, damage to the grid element body 5 is also avoided. Therefore, it is possible to mass-produce the auto-convergence color cathode ray tube that displays a high-definition image.

In the above example, the index phosphor pattern 3 is formed on the color selection electrode formed by arranging the thin grid elements 5 at a predetermined pitch. However, the index phosphor pattern is formed on the color selection electrode such as a shadow mask. The same applies to the case where 3 is formed.

On the other hand, as shown in FIG. 4, in the shadow mask 25, it has been proposed to form a low melting point frit glass film 26 on the back surface of the shadow mask 25 in order to prevent doming (thermal expansion). .. The frit glass film 26 is formed inside the edge of the beam transmission hole 27 so as not to affect the electron beam. The technique of the present invention described above can also be applied to the case where the frit glass film 26 is formed on the back surface of the shadow mask 25. That is, the Al reflection film 12 is formed on the one surface 25a of the shadow mask 25.
And dry film 11 having film-like photosensitive film 13
Are laminated and laminated, and exposed 16 from the other surface 25b side.
I do. In this exposure 16, the light is reflected by the Al reflection film 12 and is exposed to a width wider than the width of the beam transmission hole 27. Next, develop to form a resist layer that extends over the beam transmission hole and part of the mask side, and apply frit glass to the entire surface.
Shadow mask 2 by reversal development and heat treatment
A frit glass film 26 can be formed on the inner surface of the insulating layer 5 as shown in FIG.

[0026]

According to the present invention, when the index phosphor pattern is formed on the color selection electrode, the conventional manual removal work of the phosphor of the unnecessary portion is eliminated, and the damage of the color selection electrode is avoided. To be done. Therefore, it facilitates the mass production of the auto-convergence color cathode ray tube.

[Brief description of drawings]

FIG. 1 is a process chart (1) showing a method for forming an index phosphor pattern of a color cathode ray tube according to the present invention.

FIG. 2 is a process diagram (No. 2) showing the method for forming the index phosphor pattern of the color cathode ray tube according to the present invention.

FIG. 3 is a process drawing showing another example of a method of forming an index phosphor pattern of a color cathode ray tube according to the present invention.

FIG. 4 is a cross-sectional view of essential parts showing an example of a shadow mask to which the present invention is applied.

FIG. 5 is a plan view showing an example of a color selection electrode of an auto-convergence color cathode ray tube.

FIG. 6 is an enlarged plan view of a main part of FIG.

[Explanation of symbols]

 1 Color Selection Electrode 2 Index Phosphor 3 Index Phosphor Pattern 4 Slit 5 Grid Element 11 Base Film 12 Al Reflective Film 13 Photosensitive Photosensitive Film 14 Protective Film 15 Dry Film 16 First Exposure 17 Negative Mask 18 Second Exposure 19 Resist layer 20 Index phosphor

Claims (1)

Claim: What is claimed is: 1. A film-shaped photosensitive film having a reflective film is deposited on one surface of a color selection electrode, and the film-shaped photosensitive film is exposed to the first surface from the other surface of the color selection electrode. To expose a region wider than the beam transmission hole, remove the reflective film, and subject the film-shaped photosensitive film to a second exposure from one surface of the color selection electrode through a mask of a predetermined pattern, and then develop. Then, a method for producing a color cathode ray tube, characterized in that an indexing phosphor is formed on a portion removed by development.