JPH087754A - Manufacture of shadow mask - Google Patents

Abstract

PURPOSE:To prevent poor workmanship of shaping holes in the etching process for a metal base board as a work for a shadow mask resulting from poor performance of the etching operation caused by fine unsoluble foreign matters included in the etching solution. CONSTITUTION:A base board of metal is subjected to an etching process with an etching solution in manufacturing a shadow mask for a color image receiving tube. The sizes and number of pieces of such foreign matters in the solution are controlled so that no more than five pieces of a size exceeding 30um are included in 10ml etching solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a shadow mask used for a color picture tube, and more particularly to a method for etching a metal substrate.

[0002]

2. Description of the Related Art An example of a conventional method for manufacturing a shadow mask used for a color picture tube will be briefly described with reference to FIG. First, the surface of a substrate made of a metal material containing iron as a main component or a metal material containing iron and nickel as a main component is subjected to a degreasing treatment using an alkaline solution, and then an acid treatment is performed to adjust the surface of the substrate. .

Next, as shown in FIG. 1A, the substrate 1
After coating the negative type photosensitive resin 2 on both sides of the same, the circular pattern part becomes a light shielding part, for example, a large hole pattern mask 3 of about 200 μm and a small hole pattern mask 4 of about 100 μm. Using, the large hole pattern mask 3 is brought into close contact with one surface of the substrate 1, and the small hole pattern mask 4 is brought into close contact with the other surface of the substrate 1 at a corresponding position. The photosensitive resin in the area other than the pattern portion is cured.

Then, as shown in FIG. 1B, for example, development is performed with a hot water spray to remove the photosensitive resin in the unexposed portion, and then the remaining photosensitive resin is subjected to film hardening treatment and burning. Next, as shown in FIG. 1C, an etching solution, for example, a ferric chloride solution is used to perform a primary etching by a spray method, and a constant etching is performed on both surfaces of the substrate. Next, as shown in FIG. 1D, a varnish is applied to the small hole side to form the etching prevention layer 5. Then, FIG. 1 (e)
As shown in FIG. 2, secondary etching is performed on the large hole side to penetrate the small hole. Then, the etching prevention layer 5 and the photosensitive resin 2 are removed to obtain the shadow mask 6 of FIG.

However, the etching solution used in the above etching process is not disposable but is usually recycled by being circulated by a pipe and a pump because of the problems of production cost and labor. Therefore, the etching solution contains a large amount of fine insoluble foreign matters such as the photosensitive resin and the etching prevention layer that are peeled off from the substrate in the etching process, and the metal powder of the substrate. Therefore, during the etching process of the substrate, foreign matter in the etching liquid adheres to the surface of the substrate, and the foreign matter interferes with the contact between the etching liquid and the substrate, resulting in poor etching, and the holes shown in FIGS. However, there is a problem in that the defective shape is caused.

Here, FIG. 2 shows an example in which the hole is not opened at the place A where the hole should be formed due to the clogging of the hole by foreign matter.
FIG. 3 shows an example of a defective shape of the hole due to a foreign substance as shown by hole B.

[0007]

SUMMARY OF THE INVENTION An object of the present invention relates to a method for manufacturing a shadow mask used for a color picture tube, and more particularly to a shadow mask which does not have the above problems in the etching process of a metal substrate. It is to provide a manufacturing method.

[0008]

That is, according to the present invention, in the step of etching a metal substrate in the production of a shadow mask, the size and the number of foreign matters in the etching liquid used for etching the metal substrate are set to 10 m.
It is an object of the present invention to solve the above-mentioned problems by providing a shadow mask manufacturing method characterized in that the number of foreign matters having a size of 30 μm or more in 1 is controlled to 5 or less.

An example of the present invention will be described with reference to the process flow chart of FIG. First, in a conventional process, the surface of a substrate made of a metal material containing iron as a main component or a metal material containing iron and nickel as a main component is degreased and surface-treated. Then, after coating the negative type photosensitive resin on both sides of the substrate, using a large-hole pattern mask with a circular pattern part as a light-shielding part and a large-hole pattern hole with a small-hole pattern mask, on one side of the substrate The large-hole pattern mask is applied in close contact, and the small-hole pattern mask is applied in close contact with the other side of the substrate at the corresponding position. At the same time, both sides are subjected to pattern exposure by ultraviolet light, and the photosensitive resin in the area other than the circular pattern area Cure.

Next, for example, by developing with hot water spray to remove the photosensitive resin in the unexposed area, the remaining photosensitive resin is subjected to film hardening treatment and burning. Then, an etching solution, for example, a ferric chloride solution is used to perform a primary etching by a spraying method, and a certain amount of etching is performed on both surfaces of the substrate.
Next, a varnish is applied to the small hole side to form an etching prevention layer. Then, secondary etching is performed on the large hole side to penetrate the small hole. Then, the etching prevention layer and the photosensitive resin are removed to obtain a shadow mask.

Here, in the present invention, as shown in FIG. 4, the size and number of foreign matters in the etching solution used for the primary etching and the secondary etching are granularized before starting the etching step in another step. Measure with a distribution meter. Next, when 6 or more foreign substances having a size of 30 μm or more are present in 10 ml of the etching liquid, the etching liquid is filtered using a filter to remove the foreign substances.
Primary etching and secondary etching are performed using an etching solution containing 5 or less foreign matters having a size of 30 μm or more in 0 ml.

Here, under the condition of the present invention, that is, the condition that there are 5 or less foreign matters having a size of 30 μm or more in 10 ml of the etching solution, etching is actually performed by changing the size and the number of the foreign matters in the etching solution. The conditions for preventing the defective shape of the holes were empirically obtained from the following examples.

[0013]

By complying with the above conditions, foreign matter in the etching solution having a size that affects the hole shape is removed during etching, so that the foreign matter does not interfere with the contact between the etching solution and the substrate. .

[0014]

EXAMPLE An example of the present invention is shown below. <Example> First, a shadow mask was manufactured by a known method according to the process of FIG. At that time, ferric chloride solution (Baume concentration 45
Spraying method (spray pressure 2.
Etching was performed at 0 kg / cm ² ). afterwards,
When the defects of the manufactured shadow mask were examined, a hole defect due to a foreign substance at the time of etching was recognized in a ratio of 4 out of 10 plates.

At that time, the size and the number of foreign matters in the etching solution were measured using a particle counter (main body CI-1000, sampler CI-1010, sensor RLV2-100H) manufactured by CLIMET, and the sample liquid amount was 10 ml / The amount and number of particles in the etching solution were measured 4 times at a flow rate of 25 ml / min and a tare amount of 3 ml / time. Next, the measurement value of the first measurement is not used because of a large measurement error, and the results of obtaining the average of the measurement values of the subsequent three measurements are shown in Table 1. The horizontal axis of Table 1 shows the size of foreign matter (μ
m), and the vertical axis represents the average value (pieces) of the number of foreign particles measured three times.

[0016]

[Table 1]

Then, according to the manufacturing process of the present invention, the above etching solution is filtered through a polypropylene filter having a pore size of 25 μm to remove foreign matters, and the shadow mask is manufactured by the same process as above except that the shadow mask is etched. When the defect of the defective shape due to the foreign matter was examined, no defective shape due to the foreign matter was found. Table 2 shows the results of measuring the size and the number of foreign matters in the etching solution at that time using the above-described measuring machine and measuring conditions. The horizontal axis of Table 2 shows the size (μm) of the foreign matter, and the vertical axis shows the average value (number) of the number of foreign matter measured three times.

[0018]

[Table 2]

As shown in Table 1, 10 ml of etching solution
When there were an average of 6 or more foreign substances having a size of 30 μm or more, defective pores frequently occurred. As shown in Table 2, the etching solution 10
If the average number of foreign matter having a size of 30 μm or more in 5 ml is 5 or less, no defective pore shape occurs.

[0020]

In the production of the shadow mask according to the present invention, by controlling the size and the number of foreign matters in the etching solution in advance in the etching process, the hole shape defect caused by the size and the number of foreign matters is prevented. Can be prevented. In addition, as long as it has etching capability, the etching solution can be reused repeatedly, and by numerically measuring the foreign matter in the etching solution, the foreign matter in the etching solution can be efficiently filtered without unnecessary filtration. It is possible to obtain practically excellent effects such as reduction of

[0021]

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a method for manufacturing a shadow mask.

FIG. 2 is an explanatory diagram showing an example of an etching shape defect due to a foreign substance.

FIG. 3 is an explanatory view showing another example of etching shape defect due to a foreign substance.

FIG. 4 is a process flow chart showing an example of a method for manufacturing a shadow mask according to the present invention.

[Explanation of symbols]

 1 Substrate 2 Photosensitive Resin 3 Large Hole Pattern Mask 4 Small Hole Pattern Mask 5 Etching Prevention Layer 6 Shadow Mask

Claims (1)

[Claims] 1. In a process of etching a metal substrate in the production of a shadow mask used for a color picture tube,
The size and number of foreign matter in the etching solution used for etching the metal substrate is 30 μm in 10 ml of the etching solution.
A method of manufacturing a shadow mask, characterized in that the number of foreign matters having a size of m or more is controlled to 5 or less.