JPH05234510A - Forming method for phosphor screen of color cathode-ray tube - Google Patents

Abstract

PURPOSE:To eliminate concentric irregular color and color mixture in accordance with distance from a panel center with extremely easy arrangement of spray nozzles. CONSTITUTION:Spray pattern centers of a plurality of nozzles are positioned respectively on concentric circles 9 whose center is on a rotation axis of a panel 1 and whose radiuses vary in an arithmetic series form. Since radiuses from the panel 1 rotation axis to the spray pattern centers are different from each other, a superposed part of spray patterns of wash water on a panel internal surface is not positioned on a concentric circle of a specific radius. Accordingly, influence due to progress difference of washing developing is not exhibited on the concentric circles.

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 of a color cathode ray tube by a photolithography technique.
During the washing development performed after exposing the photosensitive fluorescent film through the shadow mask, the unexposed and uncured portion is uniformly washed over the entire surface, and there is no unevenness in color on the image display and color reproduction is possible. The present invention relates to a color cathode ray tube with improved overall uniformity.

[0002]

2. Description of the Related Art As is well known, the fluorescent surface of a color cathode ray tube is constructed by arranging a large number of dots or stripes of fine primary color fluorescent materials in a repeating sequence. After forming a photosensitive phosphor film of a specific primary color on the entire inner surface and exposing this photosensitive phosphor film to the light transmitted through the opening of the shadow mask, the unexposed and uncured part Is washed with water to remove it,
It is manufactured by a photolithography technique that leaves only the exposed and cured portion. The photosensitive fluorescent film is
For example, as disclosed in JP-B-46-35426, a so-called slurry is prepared by suspending particles of a specific primary color fluorescent substance in a photosensitive solution composed of a mixed solution of polyvinyl alcohol and ammonium dichromate. The slurry is applied to the inner surface of the panel, and then the coating film is dried to form the coating film. In the exposure work, during the actual operation of the completed color cathode ray tube, the electrons emitted from the electron gun dedicated to the specific primary color, deflected by the deflection yoke, and passed through the shadow mask opening in the electron beam scanning the fluorescent surface. The correction lens and the light source position are appropriately set so that the fluorescent film of the same portion as the portion (the position of the picture element of the primary color) which is projected on the fluorescent surface is exposed. Therefore, the exposure and development work through the shadow mask, for the photosensitive fluorescent film of each primary color,
For example, the processes are repeated separately in the order of green, blue, and red.

[0003]

Since the method for forming the fluorescent surface of the color cathode ray tube is as described above, for example, when the washing and developing work is performed after the exposure of the blue fluorescent film,
If the washing operation is incomplete and the unexposed and unhardened blue phosphor film remains, the blue phosphor film remains attached on the green picture element formed before blue. In addition, during the formation of the red phosphor picture element subsequent to the formation of the blue phosphor picture element, a picture element in which the blue phosphor slightly remaining in the red phosphor is mixed is formed. , Reduce the color purity of the displayed image.

Conventionally, when the inside surface of a panel after being washed and developed is closely observed, one color may appear as a ring. That is, in some cases, washing and development were incompletely performed, and the phosphor film to be removed remained in a ring shape on the inner surface of the panel. When a color cathode ray tube was manufactured by using such a panel as it was, ring-shaped color unevenness was observed concentrically and intermittently in the display image.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and provide a method for forming a fluorescent surface of a color cathode ray tube in which ring-shaped color unevenness is not seen in a display image. ..

[0006]

In order to achieve the above object, in the present invention, a photosensitive phosphor film is formed on the inner surface of the panel of the color cathode ray tube, and the panel is exposed after being exposed through a shadow mask. In the method for forming a fluorescent surface of a color cathode ray tube, the unexposed uncured portion of the fluorescent film is rotated and sprayed with washing water toward the inner surface of the panel from a plurality of nozzles to perform a developing operation. Nozzle of the center of those spray patterns,
The number of nozzles is the same as the number of nozzles, and the radius changes in a geometric progression.It exists on a concentric circle centered on the rotation axis of the panel, and the direction of the radius from the rotation axis of the panel to the center of each spray pattern is different. I decided to place it. Note that even if the radii of the plurality of concentric circles in which the nozzles are arranged change in an arithmetic series, it is not necessary that the difference between the radii of the adjacent concentric circles is strictly constant, and the average value of the radius differences is Two
It does not matter if it swings up to about 0%.

[0007]

In the washing and developing process, the water sprayed from each nozzle reaches the inner surface of the panel in a constant spray pattern. When the peripheral portions of the spray patterns from a plurality of nozzles overlap on the inner surface of the panel, water collects in the overlapping portions and the residence time becomes long. As much as water stays, unexposed and uncured parts are dissolved and washed away with a delay, and as a result, the amount of residual fluorescent substance in the overlapping portion around the spray pattern is larger than that in the non-overlapping portion. Also, since the sprayed water flows from the center of the spray pattern to the surroundings,
Although a little, near the central portion of the spray pattern, the water-washing development is more likely to proceed than at the periphery. At locations where the washing and developing process proceeded well, almost no unexposed or uncured phosphor film remained, and the peripheral areas of the exposed or cured phosphor pixels were slightly melted to reduce the size of the pixels. Effects due to the difference in the degree of progress of water washing development due to the overlap of the above spray patterns and the difference in position between the center and the periphery of the spray patterns (color mixing and size of picture elements)
When a plurality of nozzles are arranged on a straight line that passes through the vicinity of the panel rotation axis and is substantially parallel to the panel surface as in the conventional case, appears relatively concentrically around the panel rotation axis. As a result, the overall color uniformity of the color cathode ray tube is impaired.

On the other hand, in the present invention, a plurality of nozzles are
The center of each of the spray patterns is on a concentric circle centered on the rotation axis of the panel whose number is the same as the number of nozzles and whose radius changes in a geometric progression, and the center of each spray pattern from the rotation axis of the panel. Since the radii to reach the different positions are different from each other, the overlapping part of the spray pattern of the washing water on the inner surface of the panel does not exist on multiple concentric circles with specific radii around the panel rotation axis as in the past. Since the distance from the axis of rotation of the panel constantly changes, the influence due to the difference in the degree of progress of water washing development does not appear in a concentric ring shape.

[0009]

EXAMPLE A phosphor slurry was applied to the inner surface of a 51 cm panel and then dried to form a photosensitive phosphor film. This photosensitive phosphor film was exposed through a shadow mask. After that, as shown in FIG. 2A, the panel 1 was fixed by the pad 3 of the carrier 2 having a rotating mechanism. Then, the spray nozzle 4 was arranged toward the inner surface of the panel 1. For spray nozzles, Spraying Systems
Japan TGSS 0.3 was used. The nozzle has an orifice diameter of 0.5 mm, water is conically sprayed from the tip of the nozzle, and the spray pattern is circular. The water supply pipe 5 is connected to this nozzle, and the water supply pipe 5
Was fixed at an appropriate position on the support plate 6. As shown in FIG.
As shown in FIG. 1B, a large number of holes are bored, and a plurality of water supply pipes 5 are inserted by selecting appropriate holes among the large number of holes of the support plate 6 as shown in FIG. A plurality of spray nozzles 4 and spray patterns 7 of the nozzles.
8 exist on a concentric circle centered on the rotation axis of the panel whose number is the same as the number of nozzles and whose radius changes substantially in arithmetic series, and the rotation axis of the panel 1 (passes through the center of the panel). ) To the center 8 of each spray pattern 7 can be arranged such that the directions of the concentric circle radii are different from each other. As long as the support plate 6 as shown in FIG. 2 (b) is made once, it is possible to cope with the washing and developing work of various types of color cathode ray tubes. After exposing the photosensitive fluorescent substance film to light, the unexposed and uncured portion of the photosensitive fluorescent substance film is washed by spraying washing water from the nozzle 4 while rotating the panel 1 as described above. Removed. According to the results of the experiment, the best results are obtained when the differences in the radii of the adjacent concentric circles in which the centers 8 of the spray patterns 7 of the plurality of nozzles are all the same, that is, when they change in the arithmetic series, the concentric circle shape is obtained. Almost no uneven color mixture was observed, but the difference in radius between adjacent concentric circles was 2
When the variation was 0% or more, concentric color unevenness of the displayed image due to unevenness in the washing and removing work was conspicuous.

In the display image of the color cathode ray tube on which the fluorescent surface was formed by the method of the present invention, color unevenness and color mixing were hardly recognized, and a good yield was obtained.

[0011]

As described above, according to the present invention, by extremely simple means, concentric color unevenness and color mixture depending on the distance from the panel center are hardly recognized, and the yield is improved. The effect was obtained.

[Brief description of drawings]

FIG. 1 is a plan view illustrating an arrangement of spray patterns of a water spraying spray nozzle according to the present invention.

FIG. 2 is a side view for schematically explaining the arrangement of nozzles and panels at the time of washing and developing after exposing a photosensitive fluorescent substance film of a color cathode ray tube according to the present invention.

[Explanation of symbols]

1 ... Panel, 2 ... Carrier, 3 ... Pad, 4 ... Spray nozzle, 5 ... Water supply pipe, 6 ... Support plate, 7 ... Spray pattern, 8 ... Center, 9 ... Concentric circle centering on the rotation center of the panel.

Claims (1)

[Claims] 1. A color cathode ray tube is provided with a photosensitive fluorescent film on the inner surface of the panel, exposed through a shadow mask, and then sprayed with washing water from a plurality of nozzles toward the inner surface of the panel while rotating the panel. Then, in the fluorescent surface forming method of the color cathode ray tube, which performs the developing operation of washing and removing the unexposed and uncured portion of the phosphor film, in the plurality of nozzles, the center of each of the spray patterns is the number of nozzles. The radius of the concentric circles is the same number as the radius of the concentric circles centered on the axis of rotation of the panel, and the direction of the radius of the concentric circles from the axis of rotation of the panel to the center of each spray pattern is different. A method for forming a fluorescent surface of a color cathode ray tube characterized by being arranged.