JPS5947418B2 - Manufacturing method of color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a color picture tube, and more particularly to a method for forming a light absorption film therefor.

Generally, the fluorescent surface of a color picture tube is as shown in the first diagram.
Three types of fluorescent films that emit green, blue, and red light through light absorption films 2, 2, etc. on the inner surface of panel 1: 3G
, 3Bt 3R are regularly arranged, and these fluorescent films 3G, 3
A metal reflective film 4 is formed on the By 3R surface.

To form such a fluorescent surface, first, a photosensitive resin film containing polyvinyl alcohol as a main component is formed on the inner surface of the panel 1, exposed to light through a shadow mask, and then washed with water to remove non-exposed areas. Next, a light-absorbing paint mainly composed of graphite or the like is applied to the inner surface of the panel 1, dried and bound, and then washed with hydrogen peroxide to dissolve the remaining cured resin film. The absorption material is also removed to expose the surface on which the phosphor film is to be formed, and then a phosphor slurry is applied to the inner surface of the panel 1, exposed and developed in the same manner to form the phosphor films 3G, 3B, and 3R.

In such a conventional method for forming a fluorescent surface, when a light-absorbing paint is applied and dried, the panel 1 has its opening surface 1a
was held diagonally upward, and in this state paint was applied and dried by uniformly heating with infrared rays or hot air.

In the picture tube thus obtained, it is not possible to apply light-absorbing paint to the inner surface of the side wall 1b of the panel 1. It cannot be used in a type of receiver in which the part in front of the mode match line 1c protrudes from the cabinet.

Therefore, it is unavoidable that, only for picture tubes for push-through type receivers, during the process of applying and drying the light-absorbing paint, the panel 1 is held so that its opening surface 1a faces diagonally downward.

According to this method, the light absorption films 2, 2b on the inner surface of the panel 1 and the inner surface of the side wall 1b can be formed with sufficient thickness, but
On the other hand, the absorbing film 2c on the inner surface of the corner portion 1d of the panel 1 has a thickness of less than μ, and sufficient luminous properties cannot be obtained. 1d leaks to the outside, significantly reducing the commercial value of the receiver.

Therefore, the light absorbing films 2, 2b have a sufficient thickness not only on the inner surface of the panel 1 and the inner surface of the side wall 1b, but also on the inner surface of the corner part 1d.
There has been a demand for the development of a manufacturing method that can easily form 2c.

The present invention has been made based on the above circumstances, and provides a method for uniformly forming a light absorption film from the inner surface of the panel to the inner surface of the side wall, and particularly forming the light absorption film on the inner surface of the corner portion to a sufficient thickness. It's not a thing.

The inventors investigated the reason why the light-absorbing film on the inner surface of the corner part becomes thinner when the panel is held diagonally downward and the light-absorbing paint is applied and dried. As a result, the corner part dries out because the glass wall is thick. I learned that this is because the temperature rises slowly during the drying process, which causes some of the light-absorbing paint to flow to the side wall and become thinner before it dries.

Therefore, by specially heating the corner portions before or after coating, they succeeded in increasing the drying rate and obtaining a light-absorbing film with sufficient thickness.

Hereinafter, details of the present invention will be explained with reference to the embodiment shown in the second figure.

First, a photosensitive resin film is formed on the inner surface of the panel 1 by a conventional method, exposed to light through a shadow mask, and developed to remove the non-photosensitive resin.

Then, as shown in the second figure, the front surface of the panel 1 is mounted on a rotary vacuum chuck 5 provided with an obliquely downward direction, and the panel 1 is held so that its opening surface 1a faces obliquely downward.

Then, while rotating the panel 1, the light-absorbing paint 6 is uniformly applied from the inner surface of the panel 1 to the inner surface of the side wall 1b.

Then, as shown in the second figure, while the inner surface of the panel 1 is uniformly heated with an infrared radiation source, such as a lattice antenna 7, hot air 10 at about 80° C. is blown onto the inner surface of the corner portion 1d using a hot air nozzle 9 provided with a heating box 8.

Then, the inner surface of the panel 1 becomes about 40 degrees Celsius, and the corner part 1d
The inner surface is heated to approximately 50°C.

As a result, the drying speed of the light-absorbing paint 6 on the inner surface of the corner portion 1d is improved, and the light-absorbing paint 6 dries before it flows out, forming a light-absorbing film 2c with almost the same thickness as the inner surface of the panel 1 and the side wall 1b. be done.

Therefore, the fluorescent film may be formed by exposing the surface on which the fluorescent film is to be formed, using a normal method.

In the color picture tube thus obtained, the light absorption film 2b is well formed on the inner surface of the side wall 1b of the panel 1, and in particular, the light absorption film 2C on the inner surface of the corner portion 1d has a thickness of about 2μ, which is the same as the other parts. Therefore, light does not leak from the side wall 1b or corner portion 1d of the panel 1, and therefore, it does not look unsightly even if it is incorporated into a bush-through type television receiver.

Note that the corner heating means may be by spraying heated nitrogen or by heating the corner from the outside surface with an infrared lamp.In short, the corner may be heated to a higher temperature than the other parts of the panel. That's fine.

Furthermore, in the above-mentioned embodiment, the corner portions were heated more strongly than other portions after applying the light-absorbing paint, but the present invention is not limited to this, and even if the corner portions are heated in advance before coating, Since the heat capacity of the corner area is large, it is possible to achieve the same effect as described above by speeding up drying after coating, or to heat the corner area in advance before coating, and then heat the corner area as described above after coating. Even better effects can be obtained by heating it strongly.

According to experiments, when heating is performed by hot gas injection, the appropriate gas temperature is 60 to 90°C, and in the case of mass production by assembly line work, it is sufficient to provide 1 to 5 nozzle injection stages.

As described above, in the method for manufacturing a color picture tube of the present invention, in the step of applying light-absorbing paint to the panel and drying it, the panel is held with its opening surface facing downward, and the corner portion is Since it is heated to a very high temperature, the corners dry quickly and leakage is prevented. As a result, a good light-absorbing film can be formed on the inner surface of the panel side wall, and the light-absorbing film on the inner surface of the corner part is also sufficient. A color picture tube can be obtained that can be formed to a certain thickness and has no fear of light leaking from the side walls or corners.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of an example of a color picture tube manufactured by a conventional color picture tube manufacturing method, and FIG. 2 is an explanatory diagram showing an embodiment of the color picture tube manufacturing method of the present invention. 1...Panel, 1d...Corner section, 2
. . . Light absorption film, 2c . . . Light absorption film at the corner portion, 6 . . . Light absorption paint.

Claims (1)

[Claims] 1. In the process of applying light-absorbing paint to the inner surface of the panel and drying it, the panel is held with its opening facing downward, and the corners of the panel are heated to a higher temperature than other parts before and/or after the paint is applied. A method for manufacturing a color picture tube, characterized by heating the color picture tube to .