JPH0241141B2 - NETSUKYUSHUSEIBUTSUSHITSUHAKUMAKUNOSEIZOHOHO - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a method of forming a heat-absorbing thin film by spraying on a light-reflecting metal thin film deposited on the inner surface of a glass face plate of a color picture tube. The present invention relates to a method for producing a thin film of a heat-absorbing substance.

[Conventional technology]

The fluorescent surface of a color picture tube effectively disperses the light emitted from the fluorescent film coated on the inner surface of the face plate, which forms part of the tube, toward the front of the color picture tube, that is, toward the viewer. Therefore, a so-called methane back structure in which a light-reflecting metal thin film is deposited on a fluorescent film is generally used.

This methane back fluorescent surface has the advantage of increasing the brightness of the color picture tube and preventing the phenomenon of ion burnout. FIG. 2 is a cross-sectional view showing the structure of the main parts of such a color picture tube, and this color picture tube has a fluorescent film 2 coated on the inner surface of the face plate 1a that constitutes a part of the envelope 1. It is formed as follows. Although not shown in FIG. 2, on the surface of the fluorescent film 2, an intermediate film 3 made of a film glazing material containing an organic substance as a main component is formed on the surface of the fluorescent film 2 to make the surface smooth. A light reflective metal thin film 4 made of aluminum is deposited on the surface of the intermediate film 3 so as to cover it. A heat-absorbing material thin film 5 is formed on the surface of the light-reflective metal thin film 4 . Then, through the baking treatment, the binder of the fluorescent film 2 and the intermediate film 3 are removed by ashing.

Further, a shadow mask 6 is arranged on the back side of the heat-absorbing material thin film 5 at a predetermined distance from the heat-absorbing material thin film 5, and an electron gun 7 is housed in the net 1b.

In the color picture tube constructed in this way, the electron beam emitted from the electron gun 7 hits the phosphor film 2 corresponding to the fine holes provided in the shadow mask 6, and a color image is projected. in this case,
The transmittance of the electron beam passing through the shadow mask 6 is as low as 15 to 30%, and the remaining 70 to 85% of the electron beam collides with the shadow mask 6, and the collision energy turns into heat and increases the temperature of the shadow mask 6. become.

As a result, the shadow mask 6 is thermally expanded and deformed, and the emission position of the fluorescent film 2 corresponding to the electron beam is shifted. This is called the doming phenomenon. The color shift that occurs along with this phenomenon is called mislanding, and when this mislanding occurs, the color image quality is significantly degraded.

Therefore, in order to reduce mislanding, a heat absorbing material thin film 5 is formed on the light reflective metal thin film 4, that is, on the electron gun 7 side, thereby absorbing the radiant heat of the shadow mask 6 and suppressing thermal expansion. ing. The heat absorbing material thin film 5 is generally formed by spraying a graphite slurry. However, if spray coating is applied directly onto the light-reflective metal thin film 4, graphite will penetrate into the fluorescent film 2 through the pinholes in the light-reflective metal thin film 4, resulting in a problem that the brightness of the color picture tube will be lowered.

To solve this problem, a first film, called a barrier film, made of, for example, an aqueous acrylic emulsion, is used.
There is a method in which a second paint, that is, a graphite slurry, is spray-coated on the light-reflective metal thin film 4 to form a barrier film, and then a second paint, that is, a graphite slurry, is spray-coated to form a heat-absorbing substance thin film 5. Commonly used. An example of this will be explained with reference to FIG. A glass face plate 1a on which a thin film 4 of a light-reflecting material has been deposited is mounted on a holder 8, and one or more spray guns 10 fixed to a reciprocating machine 9 are used to spray a first paint (water-based acrylic emulsion) supplied from a bed tank 11. ) 12 to form a barrier film. At this time, the spray gun 10 moves as shown by the arrow in FIG. 4 using the reciprocating processor 9 to spray the entire surface of the light reflective metal thin film 4. The glass face plate 1a on which the barrier film has been formed is then transferred to a second paint spraying position. This state is shown in FIG. That is, the glass face plate 1a is set on the masking 13. This masking 13 is installed to prevent the second paint (graphite slurry) 15 from adhering to parts other than the fluorescent film 2 and to determine the pattern shape of the heat-absorbing substance thin film 5 (graphite film). .
Thereafter, as in the case of forming the barrier film, graphite slurry 15 supplied from the head tank 11 is spray-coated using one or more spray guns 10 fixed to the reciprocating machine 9 to coat the heat-absorbing material thin film 5.
form. During the above process, the glass face plate 1a is processed by intermittent automatic transfer operation. After the formation of the heat-absorbing thin film 5 has been completed in this manner, the product is then subjected to baking treatment to complete the process of forming the fluorescent surface.

[Problem that the invention seeks to solve]

In the method of forming a heat-absorbing substance thin film as described above,
When the glass face plate 1 is sprayed by intermittent transfer automatic operation with a cycle of 20 seconds to 30 seconds, the spray gun shown in FIG. 6 (for example, made by DeVilbis)
The aqueous acrylic emulsion 12 or graphite slurry 15 for the barrier film is dried and adhered little by little around the nozzle holes 21 of No. 20, and a film-like material 22 is formed over time.

When this film-like material 22 is formed, when the needle 23 moves up and down, the nozzle hole 21 and the needle 23
If the film 22 gets into the gap between the two or covers the nozzle hole 21, the paint will not be sprayed properly. For example, since the operation is intermittent, paint leaks from the gap between the needle 23 and the nozzle hole 21 during stoppage, and splashes onto the light-reflective metal thin film 4 in the form of droplets when spraying is started. In addition, a situation may arise where the spraying becomes intermittent or the spraying does not occur at all.

In this way, in the paint that adheres unwillingly,
In the case of aqueous acrylic emulsion, the luminous efficiency decreases, and in the case of graphite slurry, non-luminous areas are created. And when the spray condition is disturbed,
A problem arises in which the film thickness becomes defective and the quality deteriorates.

Furthermore, there is a problem in that it takes a lot of time to replace and clean the spray gun, making maintenance complicated.

This invention was made in order to solve the above-mentioned conventional problem.The nozzle of the spray gun is washed with water to prevent the paint from drying around the nozzle hole, and then the washing water adhering to the nozzle is removed by air blowing. It is an object of the present invention to provide a method for producing a thin film of a heat-absorbing material, which can be removed by application, thereby achieving proper spraying of paint and facilitation of maintenance.

[Means for solving problems]

The method for producing a heat-absorbing substance thin film according to the present invention includes washing the nozzle of a spray gun with water during the stoppage of intermittent operation, and removing the paint adhering to the periphery of the nozzle hole by washing with water until the paint has dried. Next, the cleaning water adhering to the nozzle is blown away with air.

[Effect]

In the method for producing a heat absorbing material thin film of this invention, 20
During automatic intermittent transfer operation, the spray time is 15 to 20 seconds and the stop time of the spray gun is 5 to 10 seconds. I try to flush the gun with water. That is, the spray gun that has completed spraying is stopped at a fixed position, and water is discharged from the washing nozzle to the spray gun to wash the nozzle hole of the spray gun. Next, air is ejected from the air nozzle to remove water droplets adhering to the nozzle hole of the spray gun and the air cap. This prevents water adhering to the air cap from turning into water droplets and splashing when spraying starts.

Next, aqueous acrylic emulsion 12 or graphite slurry is sprayed. In this way, since the paint is washed away with water, no paint remains around the nozzle hole, so the formation of a dry film can be prevented, and the dry paint will not get stuck in the gap between the needle and the nozzle hole. Furthermore, since the nozzle hole is not covered with a dry film, occurrences of paint splashing and uneven spraying due to paint leakage are prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, after the vapor deposition of the light-reflective metal thin film 4 is completed, the glass face plate 1a is placed on the holder 8, and the first paint is supplied from the bed tank 11 using one spray gun 10 fixed to the reciprocating machine 9. 12, that is, an aqueous acrylic emulsion 12 (for example, an aqueous solution consisting of 1 part of Primal AC-33 manufactured by Nippon Acrylic Chemical Co., Ltd. and 5 to 15 parts of pure water) is spray coated. At this time, the spray gun 10 is moved by the reciprocating device 9 to the position shown in FIG. The water washing nozzle 2 is inserted into the nozzle hole 21 of the spray gun 10 which is stopped at a fixed position (Fig. 1).
Water is released from 4 for cleaning. At this time,
At the same time, the cleaning brush 27 is operated and the nozzle hole 21
Brushing. This further enhances the cleaning effect. Next, air is ejected from the air nozzle 25 to remove water droplets adhering to the air cap 26. Next, apply a barrier film by spraying water-based acrylic emulsion 12.
End the cycle. During this dry spraying, a hood 28 was installed approximately 100 mm directly above the spray gun 10 to prevent the acrylic emulsion 12 from scattering elsewhere. Although not shown, it goes without saying that an exhaust fan is provided. Water washing time is 2 seconds to 4 seconds, air blowing time is 2 seconds to 4 seconds,
The dry blowing time was 1 second to 2 seconds. Among these set times, keep the idle time as short as possible,
The longer the air blowout time, the better. This is because the hood 28 is completely prevented from getting dirty and the air cap 26 is completely removed from water droplets.

Next, the glass face plate 1a is transferred to the second paint, that is, the graphite slurry 15 spraying position shown in FIG. 5, and the graphite slurry 15 is sprayed thereon. graphite slurry 1
As No. 5, for example, Aqua Duck manufactured by Acheson Co., Ltd. with a solid content of 3.5% was used.

The method of spraying and cleaning of the spray gun 10 is exactly the same as for the aqueous acrylic emulsion 12.

In the above embodiment, the air nozzle hole 2 of the air cap 26 was particularly used for spraying paint.
This is because it is difficult to remove water that has entered 9 by blowing out air alone.

The above method is particularly effective and applicable to water-based paints that dry easily. It is also effective in preventing dirt and dust from accumulating on the floor when the washing liquid accumulates on the floor.

〔Effect of the invention〕

As explained above, according to the method of forming a heat-absorbing substance thin film according to the present invention, it can be cleaned within a normal cycle, there is no splashing of paint from the spray gun, and uneven spraying can be prevented, resulting in good images. As a result, the quality of color picture tubes can be improved. In addition, spray gun maintenance, which was previously performed every 1 to 2 hours, will now be performed approximately every 40 to 50 hours, greatly improving work efficiency.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing a spray gun cleaning method according to the present invention, FIG. 2 is a cross-sectional side view of an example of a color picture tube, and FIG. 3 is a schematic explanatory diagram showing a conventional barrier film manufacturing method. Fig. 4 is an explanatory diagram showing the movement of the spray gun, Fig. 5 is a schematic explanatory diagram showing the conventional method of spraying graphite slurry, and Fig. 6 is an explanatory diagram showing the movement of the spray gun.
The figure is an enlarged sectional view of the main parts of the spray gun. 1a... Face plate, 2... Fluorescent surface, 4
...Light reflective metal thin film, 5... Heat absorbing material thin film, 10... Spray gun, 12... First paint, 15... Second paint. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first paint is applied as a barrier film using a spray gun on the light-reflective metal thin film deposited on the fluorescent film on the inner surface of the glass face plate of the cathode ray tube, and a second paint is applied on top of it using a spray gun. In the method for forming a thin film of a heat-absorbing substance by coating, the nozzles of the spray guns are washed with water at a time other than when the spray guns are spraying, and then air is blown onto the nozzles to remove the washing water. 1. A method for producing a thin film of a heat-absorbing substance, the method comprising: removing a thin film of a heat-absorbing substance;