JP2003077408A - Color cathode-ray tube and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode-ray tube and its manufacturing method achieving both denseness and adhesiveness of a coating film all over the inside face of a panel. SOLUTION: Adhesive force of a coating film is improved at a corner part by making surface roughness of a corner part 1B of an inner face of a panel 1 used for the color cathode-ray tube larger than that of a center main part 1A, and a phosphor screen dense and without exfoliation is obtained for the whole panel. Further, distribution of the above surface roughness is realized by forming micro ruggedness with distributed sizes on a male mold used for press molding of the panel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube and a manufacturing method thereof, and more particularly to a structure of a face panel and a manufacturing method thereof.

[0002]

2. Description of the Related Art A color cathode ray tube 21 suitable for image display in computer terminal displays, high-definition televisions, etc.
Has a structure as shown in FIG. That is, a glass face panel (hereinafter, referred to as a panel) 22 and a glass funnel 23 are integrally joined by a frit glass 24 to have a bulb 25, and inside the panel 22, green, blue, and red are provided. A phosphor surface 26 in which phosphors that emit light are arranged in a dot shape or a stripe shape is formed by coating, and behind this phosphor surface 26 are shadows in which a large number of electron beam passage holes are formed at regular intervals. A shadow mask structure in which the mask 27 is welded and fixed to a mask frame 28 is locked and fixed by panel pins 29 embedded in the inner wall of the panel 22. Cone part 3 of the funnel 23
A conductive layer 33 made of a conductive material such as graphite is formed on the inner surface from 2 to the neck portion 30. Funnel 2
An electron gun 31 that emits three electron beams is arranged in the neck portion 30 of the valve 3, and a valve spacer 34 that is electrically connected to the accelerating electrode is made of elastic metal and is pressed against the conductive layer 33. A deflection yoke 35 for changing the direction of the electron beam is arranged outside the funnel 23 from the neck portion 30 to the cone portion 32. Then, a high voltage is applied from the outside to the accelerating electrode through the conductive layer 33 to accelerate the electron beam, and the deflection yoke 35 controls the direction of the electron beam to select green, blue, or red by the shadow mask 27. The fluorescent screen 26 is irradiated with an electron beam corresponding to the above to cause the corresponding fluorescent material to emit light, thereby displaying an image.

The fluorescent screen 26 is formed along the process shown in FIG. First, the panel 22 is thoroughly washed and dried.
Next, the panel 22 is rotated at a high speed, and a photosensitive resin liquid is dropped on the center of the inner surface of the panel 22 to apply it thinly and uniformly by spin coating, followed by drying to form a photosensitive film 42 (a). Next, the positions where the green (G), blue (B), and red (R) phosphors are formed are sequentially exposed to ultraviolet rays through the mask 43 to cause a crosslinking reaction (b). Next, the panel 22 is developed to remove the unexposed portion of the photosensitive film 42 and dry the exposed portion of the photosensitive film 42 (c). Next, the graphite coating liquid is sprayed while rotating the panel 22 to coat the graphite 44 on the inner surface of the panel 22 (d). Next, the photosensitive film 42 is swollen and peeled to remove the graphite 44 on the photosensitive film 42, and a black matrix film (BM film) 45 having holes at the positions where the respective phosphors are formed is formed. Unnecessary graphite 44 applied to the end portion (seal portion or the like) of the skirt portion is washed and removed (e). Next, the photosensitive resin and the green phosphor 46 (for example,
A slurry in which ZnS: Cu, Al) is mixed is applied, dried, and then exposed and developed to fill and form the green phosphor 46 in the green hole of the BM film. Hereinafter, a blue phosphor 47 (for example,
ZnS: Ag), red phosphor 48 (eg, Y ₂ O)
The same process is repeated for ₂ S: Eu ³⁺ ) to form a dot-shaped or stripe-shaped color fluorescent film (f). Next, a filming liquid is applied on the fluorescent film and the BM film to form a filming film 49 (g). Next, an aluminum vapor deposition film 50 is formed as a mirror-like metal film on the filming film 49 (h). Finally, the panel is fired to remove the organic components such as the binder and the filming liquid to obtain the desired fluorescent screen 26.

[0004]

The inner surface of the panel 22 used for the color cathode ray tube has a glass surface in order to improve the adhesiveness between the glass surface and a coating film such as a BM film or a fluorescent film. Small irregularities of a certain size are formed. The fine irregularities are manufactured by the following press molding. That is, as shown in FIG.
The female mold 60 having the recess 60a having the same shape as the outer surface of the second mold is horizontally fixed, and then the molten glass 61 is injected into the recess 60a. Next, as shown in FIG. 6B, a convex portion (press surface) 62a having the same shape as the inner surface shape of the panel.
Male mold 62 having
Stop at a predetermined position, and after the molded glass solidifies, the male mold 6
Raise 2. Since the convex portion 62a of the male die 62 is formed beforehand with minute irregularities of a certain size and processed to have a predetermined surface roughness, the entire inner surface of the press-molded panel 22 also has the same surface roughness. There is.

Usually, in order to form a dense and fine coating film, the surface roughness of the inner surface of the panel is set small. On the other hand, since coating and drying are performed while rotating the panel, the thickness of the coating film at the corners of the panel becomes thicker than that at the central main portion. For this reason, there is a problem that the adhesive force of the coating film is insufficient at the corner portion, and film peeling easily occurs. When the inner surface of the panel is roughened in order to prevent the peeling of the film at the corners, the texture of the coating film becomes rough over the entire panel, which causes a new problem that the display quality is deteriorated. These problems occur because the surface roughness of the inner surface of the panel is the same throughout. Since the denseness and adhesiveness of the coating film are affected by the surface roughness of the underlayer, and the two are in conflict with each other, it is not easy to keep the balance with the same surface roughness.

Therefore, the present invention has been proposed in view of the above problems, and an object thereof is to ensure the denseness of the coating film in the central main part occupying most of the panel and to prevent the film peeling in the corner part. It is an object of the present invention to provide a surely prevented color cathode ray tube and a manufacturing method thereof.

[0007]

In order to solve the above-mentioned problems, a color cathode ray tube of the present invention is a color cathode ray tube having a panel having a phosphor screen, and a surface roughness of a corner portion of an inner surface of the glass of the panel is provided. It is characterized in that the roughness is made larger than the surface roughness of the central main part. With this configuration, the adhesive force of the coating film is increased at the corner portion, so that the coating film can be prevented from peeling off. Since it is not necessary to increase the surface roughness in the central main portion, the denseness of the coating film can be secured. Therefore, it is possible to provide a color cathode ray tube having a dense and non-peeling phosphor screen over the entire inner surface of the panel.

Further, the color cathode ray tube of the present invention is characterized in that the surface roughness of the inner surface of the glass of the face panel is continuously increased from the central main portion to the corner portion.
According to this configuration, the adhesive force of the coating film continuously increases from the central main portion toward the corner portion, so that peeling does not occur at a specific boundary.

Further, in the color cathode ray tube of the present invention, the surface roughness of the corner portion is made larger than the surface roughness of the central main portion, and the surface roughness of the central main portion is 0.8 μm or less, preferably 0.2 to 0.2 μm. It is characterized in that the surface roughness of the corner portion is selected to be 0.8 μm or more, preferably 0.8 to 1.4 μm. With this configuration, it is possible to form a dense and well-balanced phosphor screen without peeling over the entire inner surface of the panel.

The method of manufacturing a color cathode ray tube according to the present invention comprises a step of forming fine irregularities whose size increases from the central portion to the peripheral portion of the pressing surface of the male die, and the male die and the female die on which the fine irregularities are formed. The method is characterized by comprising a step of press-molding a molten glass with a mold to form fine irregularities on the inner surface of the panel, and a step of forming a fluorescent surface on the inner surface of the panel. According to this method, it is possible to easily and reliably form a minute unevenness distribution of a desired size on the inner surface of the panel, and it is possible to manufacture a color cathode ray tube having a dense and non-peeling fluorescent surface over the entire inner surface of the panel.

Further, in the method for manufacturing a color cathode ray tube of the present invention, high hardness powders having different particle diameters are sequentially ejected onto the pressing surface of the male die at different positions to sequentially eject the pressing surface from the central portion of the pressing surface to the peripheral portion. It is characterized in that minute irregularities whose sizes gradually increase over time are formed. According to this method, desired fine irregularities can be formed easily and reliably.

Further, according to the method of manufacturing a color cathode ray tube of the present invention, powder having a constant particle diameter is jetted onto a male press surface, and the jetting condition is changed so that the central portion to the peripheral portion of the press surface is changed. It is characterized in that minute irregularities whose sizes are successively increased are formed. Also by this method, desired minute irregularities can be easily formed.

Further, the method of manufacturing a color cathode ray tube according to the present invention is characterized in that a fine concavo-convex whose size gradually increases from the central portion to the peripheral portion of the male pressing surface is formed by a lithography method. According to this method, it is possible to surely form the desired minute irregularities with high accuracy.

[0014]

The color cathode ray tube of the present invention is characterized by the structure of the panel. That is, fine irregularities whose size increases from the central main portion to the corner portion of the inner surface of the panel are formed, and the surface roughness is not constant like the conventional panel but has a distribution. Hereinafter, embodiments of the color cathode ray tube of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a rectangular panel 1 viewed from the inner surface side, and particularly, schematically shows the size and distribution of the minute irregularities 10 formed on the inner surface by the size and arrangement of circles. Large circles and large surface roughness at the corners. In the central main portion 1A, which occupies most of the panel 1, the surface roughness is small and almost constant. In the central main portion 1A, the circle is omitted. FIG. 2 is an enlarged cross-sectional view of a main part of the minute unevenness 10 taken along line XX of FIG. As shown in FIGS. 1 and 2, the minute unevenness 10 on the inner surface of the panel is formed in the central main portion 1
From A to the four corner portions 1B, 1B, ..., It continuously increases. It is substantially point-symmetric with respect to the center (C) of the panel. There is almost no difference between the corners. The surface roughness of the central main portion is selected to be 0.8 μm or less, for example, in the range of 0.2 to 0.8 μm in consideration of the denseness and adhesiveness of the coating film. The surface roughness of the corner portion 1B is similarly selected from the range of 0.8 μm or more, for example, 0.8 to 1.4 μm.

Next, a feature of the method of manufacturing a color cathode ray tube of the present invention is the method of forming fine irregularities. Hereinafter, embodiments of the manufacturing method will be described with reference to the drawings. In order to provide a distribution of the surface roughness on the inner surface of the panel, it is necessary to form minute irregularities of different sizes, particularly on the pressing surface of the male mold of the pair of male and female press molds. Hereinafter, an example of forming fine irregularities by the sandblast method will be described with reference to FIG. As shown in FIG. 3 (a), the male die 2 is arranged with the pressing surface 2a facing down, and is rotated around the axis. On the other hand, the nozzle 3 is arranged below the center of the male die 2 and the powder 4 is sprayed. The nozzle 3 is composed of a plurality of nozzles 3a, 3b, 3c. Figure 3
Only the nozzle 3a is shown in FIG. While the high hardness powder 4a is jetted from the nozzle 3a toward the press surface 2a of the male die 2 at high speed, the nozzle 3a is moved in the radial direction of rotation of the male die 2 along the surface of the male die from the central portion to the peripheral portion. Move toward point B. When the point B is reached, the injection of the nozzle 3a is stopped. During this time, the nozzles 3b and 3c do not eject the powder. The average particle size of the powder 4a is selected from 0.2 to 0.8 μm. By this step, minute irregularities of uniform size are formed in the central main portion of the pressing surface 2a of the male die 2. The male press surface may be arranged upward.

Next, as shown in FIG. 3B, the nozzle 3
The nozzle 3b is moved from point B toward point A, which is closer to the end, while the powder 4b having a slightly larger average particle size (0.8 to 1.0 μm) is jetted from b at a high speed. During this time, the nozzles 3a and 3c do not eject. By this step, a slightly larger size of fine irregularities is formed in the region from the point B to the point A on the pressing surface 2a of the male die 2. Note that only the nozzle 3b is illustrated in FIG.

Next, as shown in FIG. 3 (c), the nozzle 3
The nozzle 3c is moved from point A toward the end of the male mold 2 while jetting powder 4c having a larger average particle size (1.0 to 1.4 μm) from c at high speed. During this time nozzle 3
A and 3b are not jetted. By this step, larger unevenness having a larger size is formed from the point A of the pressing surface 2a of the male die 2 to the end portion. In FIG. 3C, the nozzle 3
Only c is shown.

Since the powder ejected from the nozzle has a slight spread, irregularities of different sizes due to powders having different average particle sizes are mixed at points B and A on the peripheral edge, and the irregular size has an extreme boundary. This is not possible, and the distribution is such that the surface roughness changes substantially continuously. In the above embodiment, three types of powder having an average particle size were used, but at least two types are required. Of course, four or more types may be used. The more types, the smoother the surface roughness distribution. The type of powder particle size is appropriately selected in consideration of the balance between the denseness and the adhesiveness of the film applied to the panel.

As a modification of the method of forming fine irregularities, it is possible to fix the powder to the same particle size and change the spraying speed, angle, time, etc. of the powder to give a distribution to the surface roughness. This method is excellent in mass productivity.

A lithographic method can also be used as another forming method, which has the advantage of high processing accuracy. The resist used as the mask is exposed to light, an electron beam, ultraviolet rays, an ion beam, or the like. The fine processing of the pressed surface through the resist is performed by chemical or physical etching.

[0021]

As described above, in the color cathode ray tube of the present invention, the surface roughness of the corner portion of the panel inner surface is made larger than the surface roughness of the central main portion, and the surface roughness of the central main portion is 0. 0.8 μm or less, for example, 0.2 to 0.8 μm is selected, and the surface roughness of the corner portion is 0.8 μm or more, for example, 0.8 μm.
Since the thickness is selected from 8 to 1.4 μm, it is possible to provide a color cathode ray tube having a dense and non-peeling phosphor screen over the entire inner surface of the panel.

In the method of manufacturing a color cathode ray tube of the present invention, high hardness powders having different particle diameters are sequentially sprayed on the pressing surface of a male die for press-molding a panel, or powders having a constant particle diameter are used. By changing the injection conditions of the body or by lithographic method, minute irregularities of increasing size are formed from the central part to the peripheral part of the press surface, so the surface roughness of the inner surface of the panel after press molding can be easily and reliably performed. It is possible to manufacture a color cathode ray tube having a phosphor screen that can form a distribution and that is dense and does not peel off over the entire inner surface of the panel.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a surface roughness distribution on an inner surface of a panel used for a color cathode ray tube of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part taken along line XX of FIG.

FIG. 3 is a diagram for explaining a method for forming fine irregularities on a male die of a press-molding die.

FIG. 4 is a diagram showing the structure of a conventional color cathode ray tube.

FIG. 5 is a diagram illustrating a conventional phosphor screen forming process of a color cathode ray tube.

FIG. 6 is a diagram illustrating a method for manufacturing a conventional color cathode ray tube panel.

[Explanation of symbols]

1 panel Central main part of 1A panel 1B panel corner 2 male 2a Male type press surface 3 nozzles 4 powder 10 Micro unevenness

Claims (7)

[Claims] 1. A color cathode ray tube provided with a face panel having a phosphor screen, wherein a surface roughness of a corner portion of an inner surface of glass of the face panel is made larger than a surface roughness of a central main portion. Cathode ray tube. 2. The color cathode ray tube according to claim 1, wherein the surface roughness of the inner surface of the glass of the face panel is continuously increased from the central main part to the corner part. 3. The surface roughness of the central main part is selected from 0.8 μm or less, and the surface roughness of the corner part is selected from 0.8 or more, according to claim 1 or claim 2. Color cathode ray tube. 4. A step of forming fine concavities and convexities whose size increases from the central portion to the peripheral portion of the pressing surface of the male mold, and a face is formed by press molding molten glass with the male and female molds on which the minute concavities and convexities are formed. 1. A method of manufacturing a color cathode ray tube, comprising: a step of forming fine irregularities on an inner surface of a panel; and a step of forming a phosphor screen on an inner surface of the face panel. 5. A method of forming fine irregularities, the size of which gradually increases from the central portion to the peripheral portion of the pressing surface by sequentially injecting high hardness powders having different particle diameters onto the pressing surface of the male mold. The method of manufacturing a color cathode ray tube according to claim 4. 6. Forming fine irregularities of which the size gradually increases from the central portion to the peripheral portion of the pressing surface by injecting powder having a constant particle diameter onto the pressing surface of the male die and changing the injection conditions. 5. The method for manufacturing a color cathode ray tube according to claim 4, wherein. 7. The method of manufacturing a color cathode ray tube according to claim 4, wherein minute unevenness having a size gradually increasing from the central portion to the peripheral portion of the male pressing surface is formed by a lithography method.