JPH0241139B2 - KEIKOMENNOFUIRUMINGUHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for filming a fluorescent screen of a cathode ray tube.

[Prior Art] Generally, the fluorescent screen of a cathode ray tube is made by depositing a predetermined phosphor on the inner surface of a glass panel to form a fluorescent film, and then depositing a metal with good electron transparency, such as aluminum, on this fluorescent film. A so-called metal back treatment is performed. Normally, a high voltage of 10 kV is applied to the phosphor screen of a cathode ray tube, and electron beams accelerated by this high voltage are made to strike the phosphor film, causing the phosphor to emit light. At this time, the metal back, that is, the metal vapor deposited film formed on the fluorescent film, not only keeps the fluorescent film conductive, but also allows most of the emitted light to be extracted to the front side of the glass panel due to its mirror effect. It also plays a role in protecting the phosphor from collisions with ion particles.

Figure 1 shows the conventional manufacturing process of a fluorescent film for a color cathode ray tube with a metal back of this type.
Further, the details are shown in FIGS. 2 to 6. As shown in Fig. 1, the manufacturing process for the phosphor film of a color cathode ray tube that is coated with a metal back consists of a phosphor deposition process 1, a filming process 2, an aluminum vapor deposition (metal back) process 3, and a baking process 4. Specifically, the processing is performed as shown in FIG.

That is, the glass panel 2 for color cathode ray tube
After cleaning, a light-absorbing layer pattern 22 is formed by depositing a light-absorbing substance such as graphite on the non-light-emitting region of the fluorescent film by applying a photographic method or the like. (Figure 2A). Next, a phosphor of a predetermined color is suspended in a liquid containing an organic photosensitive agent such as polyvinyl alcohol and dichromate as main components, and coating, exposure and development are repeated for each color to form the light absorption layer pattern 22. For each corresponding portion of the light-emitting area of the fluorescent film, the three primary colors green 23 and blue 2
4 and then deposit stripes or dots of each phosphor of red 25 (FIG. 2B). In this manner, the phosphor adhesion step 1 is completed, and the process proceeds to the filming step 2.

This filming process 2 is a pretreatment for the next aluminum vapor deposition process 3, and forms a thin organic film on the phosphor film deposited in the phosphor deposition process 1. This is done because direct aluminum vapor deposition would result in aluminum being deposited directly on the surface of the phosphor, making it impossible to form a continuous and smooth metal vapor deposition film. Emulsion type filming, which is generally adopted as this process, will be explained with reference to FIGS. 3 to 6.

The glass panel 21, which has undergone the final phosphor deposition process (development process) as described above, is held by a panel carrier 31 shown in FIG.
1 (FIG. 4A), it is first preheated to about 40°C, and while being rotated at a constant speed by the drive motor 34,
An aqueous emulsion (hereinafter referred to as lacquer liquid) 32 whose main component is an acrylic emulsion, for example B-74 manufactured by Nippon Acrylic Co., Ltd., is poured onto the fluorescent film through a nozzle 33. Next, this is moved to a position facing a large number of heaters 41, for example, and the lacquer liquid 32 is shaken off by rotational centrifugal force and heated and dried to form a smooth lacquer coating of polymethacrylate resin on the fluorescent film. 26 (FIG. 2C). That is, the lacquer solution 32 is processed through the steps shown in FIG.
Each particle of the emulsion is heated and coagulated and melted by evaporation of water to form a continuous film.

In the above-described phosphor adhesion process 1 and filming process 2, the panel carrier 31 holding the glass panel 21 shown in FIG. This is carried out using automatic fluorescent film manufacturing equipment. At this time, special care must be taken in heating and drying the lacquer liquid 32 before and after application, as this may lead to symptoms of "unevenness,""blisters," or "cracks," which will be described later, depending on the method and degree of drying. Further, the glass panel 21 that has completed the filming process 2 in this way enters the next aluminum vapor deposition process 3 and is coated with 2000 ml of aluminum on the lacquer film 26 by vacuum evaporation method.
An aluminum deposited film 27 of ~4000 Å is formed (FIG. 2C).

The metal back-treated phosphor film is then subjected to the next baking step 4 to a temperature of about 430 mm.
℃ baking treatment and the above phosphor deposition step 1.
Then, the organic components used in the filming process 2 are thermally decomposed and scattered, and the fluorescent film manufacturing process is completed.

However, in the aluminum vapor deposition step 3 and the baking step 4, if the above-mentioned filming step 2 is not appropriate, "blisters" or "foams" may occur in the vapor deposited film, resulting in a defective product. Generally, in order to improve the properties of the aluminum deposited film 27, it is necessary to dry the lacquer solution 32 more quickly to form a homogeneous and smooth lacquer coating 26 on the fluorescent film. However, in manufacturing using the automatic fluorescent film manufacturing apparatus, the lacquer liquid 32 is usually collected and used repeatedly, so that the lacquer coating 26 deteriorates over time.
The quality was changing.

That is, the excess of the lacquer liquid 32 is collected in a collection tank installed under the glass panel 21 as shown in _FIG . It is returned to the head tank 63 and used repeatedly. Also,
The amount of liquid in the head tank 63 is reduced by the supply tank 6.
4, new lacquer liquid 32 is added by liquid level control.
It is replenished via a filter 66 by a pump 65 of P ₂ .

Filming process 2 under these conditions of use
During this process, the Lutzker coating 26 sometimes develops bubbles 50 as shown in FIG. 7A over time.
and unevenness 51, blisters 52 as shown in FIG. 7B, and lacquer fluid 32 as shown in FIG. 7C.
The glass panel 21 was stained 53 by the scattering of the particles. Like this, bubbles 50, blisters 5
2 and the dirt 53 on the glass panel 32 will reduce the brightness of the phosphor screen and will significantly impair the uniformity of the white screen, resulting in undesirable results.

Conventionally, in order to eliminate this inconvenience, one of the reasons is that if the quality of the lacquer coating 26 deteriorates (usually determined after performing the aluminum vapor deposition step 3),
This method has been based on methods such as discarding the lacquer liquid 32 in the head tank 63 as shown in Fig. 6 and replacing it with a new one, or adjusting the temperature of the heater 41 shown in Fig. 4 for heating drying to be lower than a predetermined value. In the latter case, even if the blisters 52 were improved, there was a risk that the overall quality of the lacquer coating 26 would deteriorate, and there was a problem in how to solve this problem. Therefore, such conventional methods have drawbacks such as a reduction in quality and yield, loss of material, and furthermore, difficulty in controlling the filming process 2.

[Summary of the Invention] It is an object of the present invention to provide a method for filming a phosphor screen that eliminates the above-mentioned conventional drawbacks, obtains a high-quality lacquer film, makes effective use of materials, and facilitates control of the filming process. With the goal.

In this invention, after injecting the lacquer liquid, the rotation of the glass panel is stopped, and together with the lacquer liquid,
This was created based on the idea of transporting foam from within the effective screen on the inner surface of the glass panel using gravity, and was completed after testing confirmed that foam could be discharged extremely effectively and reliably. This is what led to this. In addition, this invention eliminates "blistering" caused by the film thickness caused by unevenness of the Lacquer solution that occurs at the time of injection, the effective use of materials by reliably collecting excess Lacquer solution, and the inconvenience caused by the scattering of the Lacquer solution when shaken off. etc. can be resolved at the same time.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in further detail.

Figure 8 shows filming process 2 according to this embodiment.
3 is a graph showing the rotation speed of the glass panel during the lacquer liquid injection/coating process and the time schedule for lacquer liquid injection. In the same figure,
First, after 6 seconds have elapsed, a lacquer solution is injected into the rotating glass panel for 5 seconds, and then the rotation of the glass panel is stopped for 4 seconds. Then, heating and drying treatment is performed while rotating again. That is, in the conventional example, the glass panel was continuously rotated even after the lacquer solution was injected, as shown by the solid line in FIG. 5, but in this embodiment, the rotation was stopped immediately after the lacquer solution was injected. There is.

By going through the filming process of the 14-inch color cathode ray tube set in this way, unlike conventional lacquer coatings, there is no ``bubble'' or ``flame'' caused by the thickness of the film caused by unevenness of the lacquer liquid during coating. This eliminates the problem of "blisters" or stains on the glass panel caused by scattering of the Lutzker solution, allowing the continued production of stable, high-quality fluorescent films. Further, since the rotation of the glass panel is stopped, the lacquer solution does not scatter, and as a result, the excess lacquer solution can be sufficiently recovered, and the material can be used effectively.

It goes without saying that the injection time and stop time of the lacquer solution are not limited to those described in the above-mentioned embodiments, and that there are various forms depending on the manufacturing control of the rotation speed and the situation of the process.

In other words, the rotational speed should be low enough to allow the injected lacquer liquid to fall along the inner surface of the glass panel due to gravity in the latter half of the injection application, but the optimum rotational speed should be set to zero. Good.

During drying after the injection of the lacquer liquid, the lacquer liquid adhering to the panel skirt part is washed with pure water 81 using a panel skirt cleaning machine, a so-called trimming machine, as shown in Fig. 8, as in the past. This process is carried out in such a way that it does not interfere with subsequent processes.

[Effects of the Invention] As explained above, according to the present invention, the rotation speed of the glass panel is such that the excess lacquer liquid can be dropped by its gravity in the latter half after injection and application of the lacquer liquid. This allows bubbles contained in the lacquer liquid to be discharged outside the effective screen of the glass panel, and also eliminates non-uniformity of the lacquer coating due to unevenness of the lacquer liquid. In particular, it can exhibit excellent effects in the quality, process yield, material yield, cleanliness of glass panels, and control of process equipment in the filming process where lacquer liquid is recovered and used.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the manufacturing process of the fluorescent film.
Figure 2 is a cross-sectional view illustrating the manufacturing process of a fluorescent film for a color cathode ray tube, Figures 3 and 4 are explanatory diagrams showing the equipment used in the filming process, and Figure 5 is a conventional method for filming a fluorescent film. FIG. 6 is a schematic diagram showing an apparatus for recovering Lacquer liquid, FIG. 7 is an explanatory diagram showing the drawbacks of the conventional filming process, and FIG. 8 is an embodiment of the present invention. FIG. 9 is a graph showing a time schedule according to a fluorescent film filming method, and is an explanatory diagram showing a state in which a trimming machine is used to clean a skirt portion. 21... Glass panel, 26... Lacquer film, 27... Aluminum vapor deposited film, 32... Lacquer liquid. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Injection of injecting and coating a lacquer solution consisting of an aqueous emulsion whose main component is a water-insoluble film-forming resin onto the fluorescent film formed on the inner surface of the glass panel while the glass panel is rotated at a predetermined rotation speed. A method for filming a fluorescent film comprising a coating step and a heating step of forming a lacquer film by heating and drying the glass panel from the coating side while rotating the glass panel, which is performed following the injection coating step. A method for filming a phosphor screen, characterized in that the rotation of the glass panel is stopped at a predetermined time after the lacquer solution is injected, or the rotation speed is set at a low enough speed that the lacquer solution falls from the inner surface of the glass panel by gravity.