JPS6011420B2 - Manufacturing method of shadow mask for color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a shadow mask for a color picture tube, and more particularly, a desired pattern is printed on a photoresist film attached to a metal plate for a shadow mask, and then developed, followed by a drying and baking process. The present invention relates to a manufacturing method in which the developer applied to the shadow mask plate is uniformly distributed when the shadow mask plate is passed through the shadow mask plate.

A shadow mask for a color picture tube usually has a large number of electron beam passing holes having a predetermined shape arranged in one metal plate, and the shapes of the electron beam passing holes are different on both sides of the metal plate. It is normal for their shapes to be different.

As a method for forming such an electron beam passage hole, a punching method using female and female molds has been proposed, but generally a photolithography technique is used. To explain the outline of the method for manufacturing a shadow mask using the photolithography technology mentioned above, first, a photoresist is uniformly applied to both sides of a metal plate having a certain thickness, and then dried to coat the entire surface with a photoresist. After forming, a negative master plate having a negative image of a relatively small electron beam passage hole on one side of the metal plate, and a negative master having a negative image of a relatively large electron beam passage hole on the other side. The original plates are pitch-aligned, placed in close contact in a vacuum, and the photoresist film at positions other than those corresponding to the electron beam passage holes is photocured using an ultraviolet light source, and then the photoresist film on the metal plate is The unexposed, uncured resin is dissolved and removed by hot water development to expose the perforated parts corresponding to the electron beam passage holes on both sides of the metal plate, and then alcohol or a surfactant is added to prevent uneven drying. to uniformly distribute the developer on the metal plate and minimize the amount of developer.

(Hereinafter, this process will be referred to as draining.) Next, the metal plate is dried, and the adhesion between the remaining photosensitive film (hereinafter referred to as resist) and the metal plate and the etching resistance of the resist itself are improved,
In order to prevent the resist from decomposing and peeling off due to the etching solution, high-temperature heat treatment (hereinafter referred to as "baking") is performed, and then the etching solution is sprayed from both sides of the metal plate to corrode the metal plate from the perforated part and release the desired electrons. Form a beam passage section. In such a manufacturing method, an ideal shadow mask is one that has a one-to-one correspondence with the negative master, but in reality, there are variations in the shape and size of the perforations in the perforated portion of the shadow mask, and Problems include poor cutting conditions around the edges.

In other words, the shape and size of the resist on the metal plate must be the same as that of the negative original plate before the etching process begins, but the above-mentioned problem is caused by variations during exposure due to non-uniformity of the photoresist film thickness. (Even if the hole shape of the negative original plate is the same, if the photoresist film is thick, the exposure will be larger than if it is thin.

). Non-uniform resist shape due to variations in development, poor cutting due to resist oozing after development, distortion of resist shape due to variation in shape, drying, uneven baking, and close contact between resist and metal plate due to insufficient baking. Distortion and peeling of the resist shape may occur due to insufficient strength and poor etching resistance of the resist. Among these, various photocuring resin coating methods have been proposed regarding non-uniformity in photoresist film thickness, and each method is adjusted to within a variation of several microns, so it is unlikely to cause defects.

In addition, the spray method is commonly used for development, and by adjusting the uniformity of the spray pattern, spray time, temperature, etc., it is possible to prevent undeveloped or overdeveloped conditions, which are a major cause of defects. It is not.
The next problem is that after the photoresist film is exposed after development, it must be kept free from oozing and distortion until the drying process begins.

The cause of this oozing and distortion of the resist is that the surface of the resist is eluted between the end of development and the end of drying, and this eluting is particularly severe in areas where there are many developer solution pools.
If the drying is accelerated in order to prevent this elution as much as possible, bumping phenomenon tends to occur in areas where there is a large amount of developer pool, and this causes resist distortion.

On the other hand, if the drying conditions are relaxed, more mist oozes out, the shape of the perforated portion deteriorates, and uneven drying is more likely to occur. In this way, developer pools can cause various undesirable results, so in the same way that a dry well is used to prevent uneven drying of photographic film, a direct drying process after development is used when manufacturing shadow masks. A method of removing water using alcohol or a surfactant solution without passing through the water has been considered, but even when such water removal processing is applied, the problem is that the water removing agent accumulates, and there is no way to prevent this accumulation. Various proposals have been made. A simple method is to feed the metal plate vertically and apply a draining agent to both sides. Since this method uses gravity, there is no problem with the drainage agent pooling, but considering mass production where shadow masks are formed one after another on long metal plates, it is desirable to perform the steps from development to etching continuously. In this case, as mentioned above, when the etching solution is continuously flowed vertically, the etching solution flows from the top to the bottom during the etching process, and the shape of the hole is distorted along the flow direction of the etching solution. It is difficult to obtain the desired hole shape. As a countermeasure to this problem, there is a method of vertically performing baking and horizontally etching, but this requires a 90° bending mechanism to make the film vertical at the position where etching begins after baking. For this reason, it is necessary to provide a long interval between baking and etching, which lengthens the process, tends to cause distortion in the metal plate, and tends to cause press defects during shadow mask forming in the subsequent process. Another method is to perform the baking process vertically, then wind up the metal plate and then etching it horizontally, but this increases the number of operations from a mass production standpoint, and requires the resist to be removed during winding. Easy to get scratches.

Furthermore, there is a method in which the dewatering agent is continuously applied horizontally and air is blown before starting the drying process after applying the dewatering agent, but this method also cannot completely blow away the dewatering agent on the metal plate. The present invention has been developed in view of the drawbacks of the above-mentioned conventional methods, and in the process of continuously flowing the metal plate horizontally from development to etching, uneven accumulation of draining agent on the metal plate after development occurs. It is an object of the present invention to provide a method for manufacturing a shadow mask for a color picture tube, which includes a draining step that prevents the deterioration in quality of the shadow mask that occurs.

That is, in the method of manufacturing a shadow mask for a color picture tube of the present invention, when etching is performed continuously while the mask is kept horizontally, when draining water after development and before drying, the mask is tilted downward once and then tilted upward. It is characterized by applying a draining agent at the time of application, or soaking it in a draining agent and then entering the drying process.

Next, an embodiment of the method of manufacturing a shadow mask for a color picture tube according to the present invention will be described with reference to FIGS. 1 and 2.

That is, the metal plate 2 that has exited the developing chamber 1 is first lowered in a downwardly inclined direction using the supports 3 and 4.

Next, the metal plate 2 is lifted up in an upward diagonal direction using support rollers 4 and 5 with a gentle inclination, and is guided to a drying oven 6 and is leveled at the entrance of this drying oven 6. . In this case, the support rollers 3, 4, and 5 do not press the entire surface of the metal plate 2 in the width direction, but press both sides of the metal plate 2 outside the effective surface of the perforation part, as shown in Fig. 2. It has become.
That is, two rollers 10, 1 are attached to a roller support frame 9 to which a constant force is applied in the direction of the arrow by a spring 8 from at least one side.
It is preferable to use a roller mechanism in which two rollers 10 and 11 are disposed opposite each other, and the edge of the metal plate 2 contacts the inner wall of the roller support frame 9 between the two rollers 10 and 11. By using such an o-roller mechanism, the metal plate 2 will not come off the rollers 3, 4, 5 even when it meanders during feeding, and the resist will not peel off after development is completed. The metal plate 2 is fed into a device having such a mechanism, and the draining agent is sprayed from both sides of the metal plate 2 with a gentle slope between the rollers 4 and 5 as shown by the arrow 7. Since it flows downward on both sides of the metal plate, the balance between the speed of this flow and the moving speed of the metal plate allows the draining agent to be applied uniformly without any local accumulation, and the amount of draining agent is also kept to the minimum necessary. It is possible to stop it within limits.

As a result, the metal plate is dried uniformly during the drying process, without any uneven drying, and the resist shape after development is fixed on the metal plate, making it suitable for color picture tubes with good perforation shape and perforation sharpness. I was able to obtain a shadow mask.

Needless to say, in the above embodiment, it is better to provide a plurality of sprays in the width direction of the metal plate. Next, another embodiment of the method of manufacturing a shadow mask for a color picture tube according to the present invention will be described with reference to FIG. In the figure, the same reference numerals as in FIG. 1 indicate the same parts, and no particular explanation will be given. In this embodiment, the roller 4 is provided in the draining agent 13 contained in the container 12 to apply the draining agent to both sides of the metal plate 2. In this case, the draining agent adhered to the metal plate 2 is can be applied uniformly by balancing the moving speed of the metal plate and gravity,
Moreover, it goes without saying that the amount of water draining agent can be used in an extremely small amount. In addition to the embodiments described above, various modifications can be made within the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view of the appearance of an apparatus having a mechanism adapted to an embodiment of the method for producing a shadow mask for a color picture tube according to the present invention, and FIG. 2 is a sectional view showing an example of the structure of the roller section in FIG. 1. , and FIG. 3 are explanatory views of the main parts of an apparatus having a mechanism adapted to another embodiment of the method of manufacturing a shadow mask for a color picture tube according to the present invention. 1...Development chamber, 2...Metal plate, 3, 4, 5
...Roller, 6...Drying room. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A step of printing and developing a desired pattern on the photoresist film attached to a metal plate for a shadow mask, and a step of lowering the developed metal plate for a shadow mask in a downward direction, then raising it in an upward direction and sending it to a drying room. A method for manufacturing a shadow mask for a color picture tube, comprising the steps of: applying a draining agent on the way up in the upward diagonal direction or near the bottom.