JP2000303190A - Preparation of shadow mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preparation method of a shadow mask while easily adjusting a proper etching liquid and prolonging a service life of the etching liquid to reduce the waste. SOLUTION: The shadow mask is prepared by spraying an etching liquid containing ferric chloride as a principal component to the surface of a thin metallic plate 20 where resists 23a, 23b having patterns corresponding to openings 24 of the shadow mask are formed to form the openings on the shadow mask by etching and recovering the sprayed etching liquid to be reused. In this case, the concentration of the etching liquid when it is stored or transported is made lower than that of the etching liquid when it is used for etching and a relatively higher concentration etching liquid is fittingly added to the etching liquid to be used for etching. The relatively higher concentration etching liquid is prepared by adding iron and chlorine to the relatively lower concentration etching liquid to chemically react with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a shadow mask for a color picture tube, and more particularly to a method of manufacturing a shadow mask with improved etching for forming an opening.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 4, a color picture tube has an envelope comprising a panel 1 and a funnel 2 having a funnel shape, and the inner surface of the panel 1 emits blue, green and red light. A phosphor screen 3 comprising a three-color phosphor layer,
Opposed to the phosphor screen 3, a shadow mask 4 having a large number of apertures formed in a predetermined arrangement is arranged inside the phosphor screen 3. Further, an electron gun 8 for emitting three electron beams 7B, 7G, 7R is arranged in a neck 6 of the funnel 2. Then, the three electron beams 7B, 7G, 7R emitted from the electron gun 8 are deflected by the deflecting device 10 mounted outside the funnel 2 to scan the phosphor screen 3 horizontally and vertically via the shadow mask 4. Thereby, it is formed in a structure for displaying a color image.

The shadow mask 4 is a color selection electrode for selecting the three electron beams 7B, 7G and 7R emitted from the electron gun 8 and making the three electron beams 7B, 7G and 7R enter the three-color phosphor layer constituting the phosphor screen 3. In order to display an image with good color purity on the phosphor screen 3, the passing amount of the three electron beams 7 (7B, 7G, 7R) crossing the aperture at different angles is made constant and the three electron beams are It is necessary that the shape 7 does not collide with the inner wall of the aperture and be reflected in the direction of the phosphor screen.

As shown in FIG. 5, in general, the opening of the shadow mask 4 is formed by a large hole 12 formed on the phosphor screen side surface and a small hole formed on the electron gun side surface. In order to eliminate the electron beam 7 (7B, 7G, 7R) which is formed in a shape conforming to the position of the electron gun near the surface of the electron gun and collides with the inner wall of the large hole 12 and is reflected toward the phosphor screen. The hole 12 is formed in an area approximately three times as large as the small hole 13.

Conventionally, the opening of the shadow mask 4 is as follows.
It is formed by a photo etching method. That is,
A photoresist is formed by applying a photosensitive agent to both sides of a strip-shaped thin metal plate made of an iron material or an iron-nickel alloy material (amber material). Next, a pair of photomasks in which patterns corresponding to the large holes 12 and the small holes 13 of the shadow mask 4 are formed are in close contact with the photoresist on both surfaces, and the photoresist on both surfaces is exposed to the pattern of the photomask. Bake. Next, the photoresist on both sides where the pattern is baked is developed to form a resist having a pattern corresponding to the large holes 12 and the small holes 13 of the shadow mask 4. Then, an etching solution containing ferric chloride as a main component is sprayed on the metal sheet on which the resist is formed, and an opening in which the large holes 12 from one surface match the small holes 13 from the other surface. It is formed by an etching method.

In the etching, an etching solution is sprayed on both surfaces of the metal sheet in an etching chamber while continuously moving the metal sheet in the longitudinal direction, and the etching liquid is provided in the middle of a path for collecting the sprayed etching solution. It is carried out by a method of regenerating with the reclaimed apparatus, collecting it in the etching solution tank, and reusing the collected etching solution. Regeneration of the recovered etchant by the regenerating apparatus is performed by supplying chlorine and water to the recovered etchant so as to maintain a constant etching ability, and converting ferrous chloride generated by etching the metal sheet into ferric chloride. The temperature, specific gravity, concentration of ferric chloride and the like of the recovered etching solution are kept at predetermined specified values.

[0007]

As described above, the opening of the shadow mask of the color picture tube is formed by a photo-etching method, and the etching of the opening is performed by etching both sides of the metal sheet on which the resist is formed. This is performed by spraying an etching solution containing ferric iron as a main component, regenerating the sprayed etching solution by a regenerating device, and reusing the recovered etching solution.

However, the above-mentioned conventional etching methods include:
There are the following problems.

In general, the higher the concentration of a ferric chloride solution, the lower its freezing point, and a high-concentrated ferric chloride solution is unsuitable for storage and transportation. On the other hand, when the opening of the shadow mask is formed by etching using a photoetching method, an etching solution having a low temperature, a high specific gravity, and a high concentration is preferable in order to stably form the opening having a desired shape. However, if the temperature is low, it takes too much time to perform the etching. Therefore, it is desired to increase the temperature for the etching. Therefore, in order to obtain stable hole formation and shorten the etching time,
An etchant having a temperature of 65 to 75 ° C., a specific gravity of 1.490 to 1.495, and a concentration of about 52.5 ° Be is desired. But,
Ferric chloride solution with a concentration of 52.5 ° Be has a freezing point of about 25
Since the temperature is ° C., when the etching is stopped and the etching liquid is left, the etching liquid solidifies when the temperature of the etching liquid is reduced to room temperature.

In other words, in order to stably form an opening having a desired shape and size in a short time without taking a long time, an etching solution having a relatively high concentration of about 52.5 ° Be is preferable. For storage and transportation, there is a problem that a relatively low concentration of about 47.5 ° Be is better.

In particular, when etching a thin metal plate made of an iron-nickel alloy, nickel in an etching solution increases with the progress of etching, and the etching ability decreases, resulting in deterioration of uneven quality due to variation in aperture area. Occurs. Further, the etching rate is reduced, and the size of the opening in the strip-shaped metal sheet changes during the etching. Moreover, it is not easy to remove nickel, which lowers the etching ability, from the etching solution. Therefore, when etching a thin metal plate made of iron-nickel alloy,
A regulated value of the nickel concentration is set, and the time when the regulated value is exceeded is regarded as the life of the etching solution, and is discarded. For example, in the case of forming an opening of a high-definition shadow mask used for a display tube by etching, the regulation value is set to about 2%, and when the regulation value is exceeded, it is discarded. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a method of manufacturing a shadow mask capable of easily adjusting an appropriate etching solution, extending the life of the etching solution, and reducing disposal. The purpose is to obtain.

[0013]

The opening is formed by spraying an etching solution containing ferric chloride as a main component on the surface of a thin metal plate on which a resist having a pattern corresponding to the opening of the shadow mask is formed. In a method of manufacturing a shadow mask in which an etching solution is formed and a sprayed etching solution is collected and reused, the concentration of the etching solution during storage and transportation is relatively lower than the concentration of the etching solution when performing the etching. When etching is performed, iron and chlorine are added to the relatively low-concentration etching solution to form a relatively high-concentration etching solution by a chemical reaction, and this relatively high-concentration etching solution is used during etching. It was appropriately added to the etching solution.

In addition, an etching solution containing ferric chloride as a main component is sprayed on the surface of the thin metal plate on which a resist having a pattern corresponding to the opening of the shadow mask is formed, and the opening is formed by etching. In a method of manufacturing a shadow mask in which a sprayed etching solution is collected and reused, a ferric chloride solution having a relatively lower concentration than the concentration of the etching solution at the time of performing the etching is stored. Iron and chlorine are added to a low-concentration ferric chloride solution to form a relatively high-concentration ferric chloride solution by a chemical reaction, and this relatively high-concentration ferric chloride solution is etched. The concentration and specific gravity of the etchant were kept constant by appropriately adding to the etchant.

Further, an etching solution containing ferric chloride as a main component is sprayed on the surface of a thin metal plate made of an alloy containing iron as a main component on which a resist having a pattern corresponding to the opening of the shadow mask is formed. In the method of manufacturing a shadow mask, the above-described opening is formed by etching, and the sprayed etching solution is collected and reused, the ferric chloride solution having a concentration relatively lower than the concentration of the etching solution at the time of performing the etching. Iron and chlorine are added to the solution to form a relatively high-concentration ferric chloride solution through a chemical reaction, and the relatively high-concentration ferric chloride solution is used to etch metals other than iron in the etching solution. The components were added as the concentration of the components increased.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows main steps of a method of manufacturing a shadow mask which is one embodiment of the present invention. As shown in FIG.
A photosensitive agent mainly containing milk alkali caseinate and ammonium bichromate is applied to both sides of a strip-shaped metal sheet 20 made of an iron-based alloy material such as an iron material or an iron-nickel alloy material (amber material). After drying, a photoresist 21 is formed. Next, as shown in FIG. 5B, patterns corresponding to the large holes on one surface side and the small holes on the other surface side (see FIG. 5) were formed in the photoresist 21 on both surfaces. A pair of photomasks 22a, 2
2b is exposed in close contact, and the patterns of the photomasks 22a and 22b are printed on the photoresist 20 on both sides. Next, the photoresist 2 on both sides where this pattern is baked
1 is developed to remove unexposed portions, and resists 23a and 23b having patterns corresponding to the large holes and small holes of the shadow mask are formed as shown in FIG. Next, an etching solution containing ferric chloride as a main component is sprayed on both surfaces of the metal sheet 20 on which the resists 23a and 23b are formed, and as shown in FIG. The small hole 13 is etched from the other surface to form an opening 24 in which the large hole 12 and the small hole 13 match. Next, as shown in (e), the resist remaining on both surfaces of the metal sheet is peeled off.

The above etching is performed by spraying an etching solution on both surfaces of the metal sheet 20 in the etching chamber 26 shown in FIG. 2 while continuously moving the metal sheet 20 having a resist formed on both sides in the longitudinal direction. Both are regenerated by the regenerating device 27 provided in the middle of the path for collecting the sprayed etchant, and
8 and a method of reusing the collected etching solution. In the regeneration by the regeneration device 27, chlorine and water are supplied to the recovered etching solution, and ferrous chloride generated by etching is changed to ferric chloride, and the temperature, specific gravity, concentration of ferric chloride, and the like are set to predetermined values. This is done by keeping the specified value.

In the above method for manufacturing a shadow mask,
In particular, in this embodiment, the concentration of the etchant when the etching is stopped and stored or transported is relatively lower than the concentration of the etchant when the etching is performed, and the concentration of the etchant is relatively lower when the etching is performed. in a low concentration etching solution was added iron, chlorine, hydrochloric acid and water, by the following chemical reaction _{Fe + 2FeCl 3 → 3FeCl 2 2FeCl} 2 + Cl 2 → 2FeCl 3, an etching solution having a predetermined concentration of relatively high concentration, the relative The etching was performed with a high concentration etching solution. Note that hydrochloric acid acts to suppress the generation of hydroxide.

In another embodiment of the present invention, as shown in FIG.
Is connected to the storage tank 29, and the concentration thereof is lower than that of the etching solution at the time of performing the etching.
The iron solution is stored, and iron, chlorine, hydrochloric acid, and water are added to the relatively low-concentration ferric chloride solution to form a relatively high-concentration ferric chloride solution by the chemical reaction. A relatively high-concentration ferric chloride solution is appropriately added to the etching solution during the etching to continue the etching.

Further, as another embodiment of the present invention, when an opening is formed in a thin metal plate 20 made of an alloy material containing iron as a main component such as an iron-nickel alloy material, other than iron which increases with the progress of etching. In order to prevent the variation of the opening area due to the alloy component of the alloy and the change of the opening size due to the decrease of the etching rate, for example, a ferric chloride solution shown in FIG. Iron, chlorine, hydrochloric acid and water are added to the relatively low-concentration ferric chloride solution in the tank 29 to form a relatively high-concentration ferric chloride solution by a chemical reaction. The ferric chloride solution was appropriately added to the etching solution during the etching with the increase of the alloy components other than iron.

When a shadow mask is manufactured by such a method, an opening of a desired shape and size can be formed stably and in a short time without taking a long time.

That is, as the ferric chloride solution generally stored and transported, a high-concentration liquid having a low freezing point is not suitable, and a low-concentration liquid having a high freezing point is desired. A commercially available ferric chloride solution also has a concentration of about 47.5 ° Be which does not coagulate under normal storage conditions. On the other hand, when the opening of the shadow mask is formed by etching, in order to form the opening of a desired shape and size stably and in a short time without taking a long time, about 52.5 ° Be (temperature of 65 to 65 ° Be). 75 ° C, specific gravity 1.49
0 to 1.495) and higher concentrations are desired.

For this reason, as in the etching in this embodiment, the concentration of the etching solution when the etching is stopped and stored or transported is made relatively low, and when the etching is performed, the concentration of the etching solution is relatively low. Iron, chlorine, hydrochloric acid and water are added to a low-concentration etching solution to make a relatively high-concentration etching solution necessary for performing etching by a chemical reaction, or
The iron solution is stored, and iron, chlorine, hydrochloric acid, and water are added to the relatively low-concentration ferric chloride solution to etch a relatively high-concentration ferric chloride solution obtained by a chemical reaction. When appropriately added to the etching solution, the coagulation of the etching solution during storage and transportation can be prevented, and the relatively low concentration of the etching solution can be promptly increased to the high concentration required for performing the etching (implementation). One form). Also,
By suppressing the change in the concentration of the etching solution during the etching (another embodiment), it is possible to form an opening having a desired shape and size stably and in a short time without taking a long time.

When holes are formed in the thin metal plate 20 made of an alloy material containing iron as a main component such as an iron / nickel alloy material, alloy components other than iron increase with the progress of etching, and Although the size of the opening changes due to the variation in area and the decrease in the etching rate, the relative concentration obtained by adding iron, chlorine, hydrochloric acid and water to a relatively low-concentration ferric chloride solution is obtained by a chemical reaction. By appropriately adding a high-concentration ferric chloride solution to the etching solution at the time of performing the etching, it is possible to suppress a sharp decrease in the etching ability, perform stable etching over a long period of time, and extend the life of the etching solution. Yes (other different forms of implementation).

Hereinafter, embodiments of the present invention will be described with reference to examples.

[0027]

Embodiment 1 As shown in FIG. 1 (a), both sides of a band-shaped thin metal plate made of an iron-nickel alloy material having a thickness of 0.25 mm are composed mainly of alkali caseinate and ammonium bichromate. A photoresist 21 is formed, and a pair of photomasks 22a, 22b are brought into close contact with and exposed to the photoresist 21 on both surfaces, as shown in FIG. 2B, and the photomasks 22a, 22b are applied to the photoresist 20 on both surfaces. After baking, the pattern was developed to form resists 23a and 23b consisting of patterns corresponding to the large holes and small holes of the shadow mask as shown in FIG. Thereafter, an etching solution is sprayed on both surfaces of the thin metal plate 20 on which the resists 23a and 23b are formed, and the sprayed etching solution is collected and reused to obtain a rectangular shape having a hole diameter of 0.15 mm × 0.57 mm. Openings were formed by etching.

As the etching solution, an etching solution having the same concentration, t = 72 ° C., a specific gravity d = 1.492, a temperature t = 65 ° C., a specific gravity d = 1.520, and a temperature different in concentration from these etching solutions t = 72 ° C., specific gravity d = 1.
The results shown in Table 1 were obtained by using three types of etching solutions of 475.

[0029]

[Table 1] The determination of uneven quality in Table 1 shows that the mark x is slightly inferior to the mark o. Among the above three types of etchants, an etchant having a temperature of t = 72 ° C. and a specific gravity of d = 1.475 is most suitable for forming an opening in view of the uneven quality and the etching time.

However, the concentration of this etching solution is about 5
Since the temperature is 2.5 ° Be and the freezing point is about 25 ° C, if the etching is stopped and stored in a normal state, the temperature will drop and it will solidify in the pipe that sends the etchant to the spray nozzle, etc. Makes it difficult to resume.

For this reason, when the etching is stopped and the etching solution is stored, the etching solution is diluted to about 47.5 ° Be that does not solidify at room temperature, and when the etching is started, the etching solution contains iron. By adding chlorine, hydrochloric acid and water to increase the concentration by a chemical reaction, the temperature can be quickly increased to about 52.5 ° Be required for etching, and a hole having a desired shape and size can be stably and quickly formed. Could be formed by etching.

[0032]

Embodiment 2 As shown in FIG. 1A, a photoresist 21 containing alkali caseinate and ammonium dichromate as main components is formed on both sides of a strip-shaped thin metal plate made of an iron material. As shown in FIG. 1B), a pair of photomasks 22a and 22b are brought into close contact with the photoresist 21 on both sides and exposed, and the patterns of the photomasks 22a and 22b are printed on the photoresist 20 on both sides and developed. As shown in (c), the resist 2 composed of a pattern corresponding to the large holes and the small holes of the shadow mask.
3a and 23b were formed. After that, this resist 23a
, 23b are formed by spraying an etching solution on both surfaces of the metal sheet 20 and recovering the sprayed etching solution for reuse.

In this case, separately from the etching solution, about 4
A relatively low-concentration ferric chloride solution of 7.5 ° Be is stored, and iron, chlorine, hydrochloric acid, and water are added to the relatively low-concentration ferric chloride solution to perform a chemical reaction. A relatively high-concentration ferric chloride solution is prepared, and the relatively high-concentration ferric chloride solution is appropriately added to the etching solution at the time of performing the above-mentioned etching, and the concentration of the etching solution is adjusted to a predetermined specified value. The etching was continued while holding down.

As a result, an opening having a desired shape and size could be formed stably and in a short time by etching.

In this etching method, a relatively low concentration of ferric chloride solution is stored in one ferric chloride solution storage tank, and the relatively low concentration of ferric chloride is stored. Iron, chlorine, hydrochloric acid and water are added to the solution to produce a relatively high-concentration ferric chloride solution by a chemical reaction, which can be supplied to a plurality of etching lines, so that the etching line can be prevented from becoming complicated.

[0036]

EXAMPLE 3 As in Example 1, both sides of a strip-shaped metal sheet made of an iron-nickel alloy material are composed mainly of alkali caseinate and ammonium bichromate as shown in FIG. A photoresist 21 is formed, and a pair of photomasks 22a, 22b are brought into close contact with and exposed to the photoresist 21 on both surfaces, as shown in FIG. 2B, and the photomasks 22a, 22b are applied to the photoresist 20 on both surfaces. After baking, the pattern was developed to form resists 23a and 23b consisting of patterns corresponding to the large holes and small holes of the shadow mask as shown in FIG. After that, an etching solution was sprayed on both surfaces of the metal sheet 20 on which the resists 23a and 23b were formed, and the sprayed etching solution was collected and reused to form openings.

In this case, apart from the etching solution, about 4
A relatively low concentration of ferric chloride solution of 7.5 ° Be is stored, and iron, chlorine, hydrochloric acid and water are added to the relatively low concentration of ferric chloride solution to perform a chemical reaction. A relatively high-concentration ferric chloride solution is prepared, and this high-concentration ferric chloride solution is added every time the nickel concentration in the etching solution increases by 0.1%, so that the specific gravity of the etching solution is 0.1%. 001
Raised.

As a result, a decrease in the etching rate due to an increase in the nickel concentration in the etching solution can be prevented. Conventionally, if the nickel concentration exceeds 2%, a variation occurs in the aperture area and the quality of the unevenness deteriorates. The life of the etching solution whose lifetime was determined when the nickel concentration exceeded 2% was doubled to 4%, and the disposal of the etching solution could be reduced.

[0039]

As described above, when the openings of the shadow mask are formed by etching using the photo-etching method, it is possible to prevent the coagulation of the etching solution when storing or transporting after stopping the etching, and to reduce the concentration of the relatively low concentration. The etching solution can be promptly brought to the high concentration required for performing the etching. Further, it is possible to form a hole having a desired shape and size stably and in a short time without spending time by suppressing a change in the concentration of the etchant during the etching.

Further, the present invention is applied to a case where an opening is formed in a thin metal plate made of an alloy material containing iron as a main component such as an iron-nickel alloy material. It is possible to prevent a change in the size of the opening due to a variation in the hole area or a decrease in the etching rate, perform stable etching for a long time, prolong the life of the etching solution, and reduce the waste of the etching solution.

[Brief description of the drawings]

FIGS. 1A to 1E are diagrams showing main steps of a method of manufacturing a shadow mask according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of an etching line according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining a configuration of an etching line according to another embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a color picture tube.

FIG. 5 is a view showing an aperture shape of a shadow mask of a color picture tube.

[Explanation of symbols]

 20: Metal sheet 23a, 23b: Resist 24: Opening

Claims (3)

[Claims] An etching solution containing ferric chloride as a main component is sprayed on a surface of a thin metal plate on which a resist having a pattern corresponding to the opening of a shadow mask is formed, and the opening is formed by etching. In a method of manufacturing a shadow mask that collects and reuses a sprayed etchant, the method stores the etchant concentration at the time of etching,
The concentration of the etching solution during transportation is relatively low, and when performing etching, iron and chlorine are added to the relatively low concentration etching solution to form a relatively high concentration etching solution by a chemical reaction. A method of manufacturing a shadow mask, wherein a relatively high-concentration etching solution is appropriately added to the etching solution at the time of performing the etching. 2. An etching solution containing ferric chloride as a main component is sprayed on a surface of a thin metal plate on which a resist having a pattern corresponding to the opening of the shadow mask is formed, and the opening is formed by etching. In a method of manufacturing a shadow mask for recovering and reusing a sprayed etching solution, a ferric chloride solution having a relatively lower concentration than the concentration of the etching solution at the time of performing the etching is stored, and Iron and chlorine are added to a low-concentration ferric chloride solution to form a relatively high-concentration ferric chloride solution by a chemical reaction, and the relatively high-concentration ferric chloride solution is subjected to the above etching. A method of manufacturing a shadow mask, wherein the concentration and specific gravity of an etching solution are kept constant by appropriately adding the etching solution to the etching solution. 3. An etching solution containing ferric chloride as a main component is sprayed on a surface of a thin metal plate made of an alloy containing iron as a main component on which a resist having a pattern corresponding to the opening of the shadow mask is formed. Forming a hole by etching, and collecting and reusing a sprayed etchant, a ferric chloride solution having a concentration relatively lower than the concentration of the etchant at the time of etching. Iron and chlorine are added to the solution to make a relatively high-concentration ferric chloride solution by a chemical reaction, and the relatively high-concentration ferric chloride solution is added to the etching solution at the time of performing the above-mentioned etching except for iron. A method for producing a shadow mask, characterized in that it is added as the concentration of a metal component increases.