JPS63235487A - Manufacture of shadow mask for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To make it possible to treat a recycled mask material by a process in common with that of a new mask material, by specifying a pretreatment stage, prior to the application of photosensitive material, for a new shadow mask material and a shadow mask material to which a sensitized film is allowed to adhere so as to make the surface of the recycled mask material uniformly clean at the time of manufacturing a shadow mask by a photodetecting method. CONSTITUTION:As to a new shadow mask material, its hoop is fitted to a winder without any treatment and seam-welded to a preceding material. Further, as to a recycled mask material to which a sensitized film is allowed to adhere, the sensitized film on the weld zone is removed and then the material is seam- welded to a preceding material. These mask materials 1 are subjected to primary alkali treatment, to treatment with warm water, and then to secondary alkali treatment. Subsequently, while supplying water, brushing (primary brushing) is applied to the mask materials 1. Then, the mask materials 1 are washed with water, and etching is applied at least to the new mask material, and brushing (secondary brushing) is applied in a similar manner as in the primary brushing, followed by water washing and pure-water washing.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a shadow mask for a color cathode ray tube, and in particular, to a method for producing a shadow mask for a color cathode ray tube. The present invention relates to a method of manufacturing a shadow mask for a color cathode ray tube that can be used.

(Prior Art) In a shadow mask type color cathode ray tube, a shadow mask is disposed inside the fluorescent screen, facing the fluorescent screen formed on the inner surface of the panel constituting the front surface of the envelope. This shadow mask, in a typical color cathode ray tube, consists of a spherical mask body in which a large number of through holes through which electron beams pass are formed in a predetermined arrangement and shape pattern, and a frame attached to the periphery of the mask body.

Typically, this shadow mask has a thickness of 0.15+++m+
A flat shadow mask having a large number of through holes is formed by photoetching using a steel plate in the form of a band of about 100 yen as a material, and then this flat shadow mask is press-molded into a spherical shape. Generally, as shown in FIG. 3, the manufacturing method for the flat shadow mask is as follows: First, a long band-shaped shadow mask material wound into a hoop shape is treated with alkali while being unwound. Remove the rust preventive oil adhering to the surface. After that, this degreased shadow mask material is washed with water, pre-etched with acid, further washed with water, and washed with pure water, and then a photosensitive agent is applied and dried to form a photosensitive film on both sides of the shadow mask material. . As the photosensitizer, casein, which has been increased or decreased with ammonium dichromate, which has high corrosion resistance, is used. Next, this photoresist film is exposed to light to print a negative pattern, and then developed.

It is baked and then etched with a ferric chloride solution to form the required through holes to form a flat shadow mask.

Shadow mask materials used include rimmed low carbon steel plates, aluminum killed low carbon steel plates, and tensile strength steels such as amber. In addition, as for the production method, there are two methods: (1) continuous flow from the introduction of the shadow mask material to etching, and (a) the process from the introduction of the shadow mask material to the formation of the photoresist film (α) exposure (c) development. , baking (d) etching, and a method in which the process is divided into parts and flowed. by the way,
In the former method of continuous flow, even if defects caused by negative patterns occur continuously during the process, for example during exposure, it is difficult to interrupt the production and the yield tends to be low; In the method of dividing and flowing each step, it is possible to interrupt the process for each divided step, and the yield can be increased. Moreover, if the latter method is used to regenerate the discontinued shadow mask material and make it usable, the material yield can be greatly improved.

As a method for recovering and recycling such shadow mask materials, Japanese Patent Application Laid-Open No. 60-228685, filed by the present applicant, describes methods for treating shadow mask materials with alkali treatment, brushing, alkali treatment, water washing, and pre-etching, as shown in FIG. A method is disclosed in which a shadow mask is manufactured from a recovered shadow mask material and a new shadow mask material in a common process by forming a photoresist film after processing in the order of , washing with water, and washing with pure water. According to this shadow mask manufacturing method, not only the uncured photoresist film before fog light but also the cured photoresist film that has been subjected to development, baking, etc. can be removed, and the shadow mask material can be recycled once.

However, this method has no problem with so-called rough shadow masks with large hole diameters and large arrangement pitches used in ordinary color cathode ray tubes, but it is not suitable for high-definition shadow masks with small hole diameters and small arrangement pitches. , due to the slight non-uniformity of its surface cleanliness,
Unevenness occurs. This unevenness does not disappear even if the conditions of the alkali treatment, ie, the alkali concentration, liquid temperature, spray pressure, etc., are changed.

(Problems to be Solved by the Invention) As described above, the conventional method of regenerating and using a recovered shadow mask is effective for ordinary color cathode ray tube shadow masks, which have relatively rough edges. For a high-definition shadow mask, slight non-uniform cleanliness on its surface causes unevenness, making it impossible to obtain a desired shadow mask.

This invention was made in order to solve this problem, and makes it possible to uniformly clean the surface of the recovered shadow mask material and manufacture a desired shadow mask using the same process as the new shadow mask material. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) In a method for manufacturing a shadow mask for a color cathode ray tube, in which a flat shadow mask is manufactured by a photoetching method, a new shadow mask material and a photoresist film are deposited and formed. A pre-treatment process before applying a photosensitive agent to the recovered shadow mask material.

A first alkali treatment step of performing alkali treatment, a step of hot water treatment after this alkali treatment, a second alkali treatment step of performing alkali treatment after this hot water treatment, and a second alkali treatment step of performing alkali treatment after this alkali treatment, while supplying water. A first brushing step of brushing, a step of pre-etching at least a new shadow mask material after this brushing, and a second brushing step of brushing at least the pre-etched shadow mask material while supplying water. It was composed of

(Function) As described above, the shadow mask material is subjected to a first alkali treatment process, a hot water treatment process, a second alkali treatment process, a first brushing process, a process of pre-etching at least a new shadow mask, and at least a pre-etching process. When the recycled shadow mask material is treated in the second brushing step, the surface of the recovered shadow mask material can be made as clean and uniform as the new shadow mask material, and the new shadow mask material and the recovered shadow mask material can be treated in the second brushing step. They can be processed in a common pre-processing step to produce the required shadow mask.

(Example) The present invention will be described below based on an example with reference to one drawing.

FIG. 1 is a process diagram for explaining one embodiment of the present invention. First, for the new shadow mask material, the hoop is attached as is to a rewinding machine (not shown), and seam welded to the previously flowing shadow mask material. In addition, for the recovered shadow mask material on which a photoresist film is adhered, the photoresist film at the welded portion is chemically or mechanically removed, and then seam welded to the previously flowing shadow mask material.

These shadow mask materials (1) are first subjected to alkali treatment as a pretreatment before coating with a photosensitive agent. In this first alkali treatment (first alkali treatment), a solution with an alkali concentration of approximately 3% containing polymeric phosphates, orthophosphates, carbonates, silicates, and surfactants as main components is heated to approximately 95°C. death,
This is done by spraying for 2 minutes at a hydraulic pressure of 1 to 2 kg/aJ. Next, warm water heated to about 60° C. is sprayed onto the alkali-treated shadow mask material (1) at a liquid pressure of 1 to 2 kg/cd for about 1 minute. This initial alkaline treatment and hot water treatment completely removes the adhering rust preventive oil from the new shadow mask material, and sufficiently swells the attached photoresist film from the recovered shadow mask material. can be done.

Next, this shadow mask material (1) is treated with alkali (
In this alkali treatment, a solution containing caustic soda as the main component and having an alkali concentration of approximately 2.5% is heated to approximately 90°C, and then heated at a liquid pressure of approximately 1 kg/aJ for approximately 2 minutes. It is done by spraying. Then wash with water. By this second alkali treatment, the previously swollen photosensitive film is almost completely peeled off and removed.

Next, as shown in FIG. 2, a nylon roll brush (2a) is applied to both sides of this shadow mask material (1).

(2b) and brushing (first brushing) while supplying water (3) to the pressure welding part. This brushing is performed by, for example, using a 0 roll brush with a diameter of about 150 m and a shadow mask material (1) of about 21 m. It is preferable to press the parts so that they have a width dimension of , and to do this at a rotational speed of about 800 rpm.

Next, this brushed shadow mask material is washed with water, and then at least the new shadow mask material is pre-etched. This pre-etching removes minute rust from the surface of the shadow mask material and adjusts the surface roughness. For this purpose, dilute nitric acid of 0.01% or less is used for rimmed low carbon steel sheets and aluminum killed low carbon steel sheets, and approximately 5% aqua regia is used for amber materials.

Note that this preetching is preferably omitted for the once-recovered shadow mask material since it has already been processed.

Next, at least this preetched shadow mask material (1) is brushed (second brushing) in the same manner as the first brushing, and then washed with water and purified water.

The shadow mask material (1) subjected to the above pretreatment is coated with a photosensitive agent while its surface is still wet, and then dried to form a photosensitive film on both sides.

Next, a negative pattern is printed on the photoresist film on both sides, and the unexposed portions are developed and removed, followed by baking. Thereafter, a flat shadow mask is obtained by spraying a ferric chloride solution on both surfaces to form through holes corresponding to the negative pattern by etching.

By the way, when the shadow mask material is pretreated by the above method, the rust preventive oil adhering to the surface of the new shadow mask material can be almost completely removed by the first alkali treatment and the subsequent hot water treatment, and For recovered shadow mask materials.

The photosensitive film adhering to the surface can be sufficiently swollen to the point where it is on the verge of falling off. The swollen photosensitive film is then removed by subsequent alkali treatment (second alkali treatment) and subsequent water washing, and subsequent brushing (first
(brushing) to complete it. The feature of this pretreatment is that hot water treatment is added after the first alkaline treatment to sufficiently swell the photosensitive film, and the second alkaline treatment with a low alkali concentration makes it possible to almost completely remove the photosensitive film. be. As a result, not only the new shadow mask material but also the recovered shadow mask material will not suffer from surface deterioration such as alkali burn, and both the new shadow mask material and the recovered shadow mask material can be cleaned and cleaned to the desired surface. It can be used as a shadow mask material.

As an example, a photoresist film is formed on a shadow mask material made of amber, and this is coated for 30 minutes in an atmosphere of about 250°C.
As a result of pre-treating the recovered shadow mask material after second baking using the above method, the photoresist film, whose chemical resistance has been significantly improved by baking, is removed and its surface becomes indistinguishable from the surface of the new shadow mask. Moreover, after that, a photoresist film is deposited and
As a result of manufacturing a high-definition shadow mask with a through-hole arrangement pitch of 0.03 mm, there is almost no unevenness, and the quality of the shadow mask is no different from that of high-definition shadow masks manufactured from new shadow mask materials. did it.

Furthermore, as a result of manufacturing a similar high-definition shadow mask by recycling the recovered shadow mask material made of a commonly used low carbon steel plate, the results shown in Table 1 were obtained. In other words, Table 1 compares the failure rate when high-definition shadow masks are manufactured from recovered shadow mask materials made of low carbon steel plates compared to when manufactured using the conventional recovery and recycling method shown in Figure 4. This is what is shown.

In Table 1, the conventional recovery and regeneration method (1) is the case where the recovered shadow mask material is pretreated by flowing at a normal speed,
For ordinary shadow masks with rough edges, this is a method that allows you to obtain the required shadow mask at a high yield from a single recovered shadow mask material, but for high-definition shadow masks,
70-80% of defects occur. In addition, in the conventional recovery and recycling method (II), the speed of the recovered shadow mask material is reduced to (I).
This is a case in which the number of defects is reduced to 1/2 of that in the above case, but even in this case, 30 to 40% of defects still occur. However, when recycled according to the method of the present invention shown in the above embodiment, the occurrence of defects can be reduced to 5% or less, and high-definition shadow masks can be produced more easily and with better yield than the conventional recovery and recycling method. Furthermore, it has been shown that the material yield of the shadow mask material can be significantly improved.

It goes without saying that by the above method, a normal shadow mask can be easily manufactured from the recovered shadow mask material at a high yield.

〔Effect of the invention〕

In a method for manufacturing a shadow mask for a color cathode ray tube in which a flat shadow mask is manufactured by a photoetching method, pretreatment before applying a photosensitizer includes a first alkali treatment, a hot water treatment, a second alkali treatment, a first brushing, If the pre-etching is performed on at least the new shadow mask material, and the second brushing is performed on at least the pre-etched shadow mask material, then the recovered shadow mask material on which the photoresist film has been deposited can be renewed. As in the case of shadow mask materials, it is possible to obtain shadow mask materials that are clean and have the required surface, and by treating the recovered shadow mask materials and new shadow mask materials in a common pretreatment process, only one ordinary shadow mask can be obtained. Without,
Compared to normal shadow masks, high-definition shadow masks with smaller through holes and hole arrangement pitch can be manufactured in the same way as with the new shadow mask material, and the material yield of the shadow mask material can be significantly improved. .

[Brief explanation of the drawing]

Fig. 1 is a process diagram for explaining a method for manufacturing a color cathode ray tube shadow mask which is an embodiment of the present invention, Fig. 2 is an explanatory drawing of the brushing method, and Fig. 3 is a conventional color cathode ray tube shadow mask. FIG. 4 is a flowchart showing a conventional recovery and regeneration method. (1)...Shadow mask material

Claims (1)

[Claims] In a method for manufacturing a shadow mask for a color cathode ray tube, in which a shadow mask material is treated in a pretreatment process, a photoresist film is deposited, and a flat shadow mask is manufactured by a photoetching method. A recovered shadow mask material having a photoresist film deposited thereon is used, and the above pretreatment step is combined with a first alkali treatment step of treating the shadow mask material with an alkali, a step of hot water treatment after this alkali treatment, and a step of hot water treatment. a first brushing step of brushing while supplying water; and a step of pre-etching at least the new shadow mask material after this brushing;
At least a second brushing step of brushing the pre-etched shadow mask material while supplying water, and treating the new shadow mask material and the recovered shadow mask material in a common pretreatment step to form a shadow mask. A method for manufacturing a shadow mask for a color cathode ray tube.