JPH0963474A - Manufacture of shadow mask for color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a shadow mask which has an etching resistant layer hard to be damaged and is easily peeled without reducing etching resistance. SOLUTION: After the first recessed hole 12 is formed in one face side of a shadow mask material 20 having resists 23a, 23b formed, the resist on this face side is peeled, an etching resistant agent is applied thereon so as to form an etching resistant layer 28, and then the second recessed hole 13 for communicating with the first recessed hole is formed on the other face side so as to form an electron beam through hole 11. Major components of the etching resistant agent are set to acrylic resin, casein, and bichromate, this etching resistant agent is applied on one face on which the first recessed hole is formed, so as to form the etching resistant layer and then ultraviolet ray is irradiated to cure.

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 for a color cathode ray tube formed by a photoetching method, and particularly to a method for manufacturing a shadow mask for a high-definition color cathode ray tube having electron beam passage holes and a small arrangement pitch. The present invention relates to a preferred method for producing a shadow mask for a color cathode ray tube.

[0002]

2. Description of the Related Art Generally, a shadow mask type color cathode ray tube has a panel 1 and a funnel 2 as shown in FIG.
In the neck 5 of the funnel 2, the shadow mask 4 is disposed inside the funnel 2 so as to face the phosphor screen 3 formed of the three-color phosphor layer formed on the inner surface of the panel 1. The three electron beams 7B, 7G and 7R emitted from the electron gun 6 disposed on the shadow mask 4 are
And a three-color phosphor layer is made to enter, and a structure for displaying a color image is formed.

The shadow mask 4 is molded into a shape similar to the inner surface of the panel 1, and a mask body 9 having a large number of electron beam passage holes formed in a predetermined array on the molding surface,
The mask frame 10 is attached to the periphery of the mask body 9. As shown in FIG. 4, the electron beam passage hole 11 of the mask body 9 is provided on one surface side facing the electron gun in order to reduce the reflection of the electron beam in the phosphor screen direction by colliding with the inner wall of the hole. Relatively small first
Is formed, and a relatively large second concave hole 13 is formed on the other surface side facing the phosphor screen.
The recessed holes 12 and 13 are formed in a communicating shape.

The mask body 9 of such a shadow mask 4 has a flat flat mask obtained by forming electron beam passage holes in a shadow mask material such as a cold rolled steel plate having a plate thickness of about 0.13 mm by photoetching. After being formed, the flat mask is manufactured by press molding into a predetermined curved surface shape.

To manufacture a flat mask by the photo-etching method, photosensitive films are formed on both sides of a shadow mask material, and the electron beam passage holes of the shadow mask, that is, the electron beam shown in FIG. A pair of negative masters having different patterns of large and small sizes corresponding to the concave holes 12 and 13 of the passage hole 11 are closely arranged and exposed to light, and the patterns of the respective negative masters are printed on the photosensitive films on both sides, and then developed. Then, a resist having a pattern obtained by inverting the pattern of the negative original plate is formed on both surfaces of the shadow mask material. After that, the shadow mask material on which the resist is formed is simultaneously etched from both sides to form electron beam passage holes. This method is called a simultaneous etching method as opposed to the two-step etching method described later.

With respect to the method of manufacturing the flat mask described above,
In particular, as a method of manufacturing a shadow mask having a small hole diameter with respect to the plate thickness used for a high-definition color Braun tube, there is a method called a two-step etching method. This method is disclosed, for example, in Japanese Examined Patent Publication No. 4-19311. In this method, similar to the above-mentioned simultaneous etching method, photosensitive films are formed on both sides of the shadow mask material, and a pair of negative masters are closely arranged on the photosensitive films on both sides and exposed to light. The pattern of the original plate is baked and developed to form a resist consisting of a pattern in which the pattern of the negative original plate is inverted on both sides of the shadow mask material, and then, as the etching in the previous stage, the other surface side that forms a large concave hole is protected. Stick the film and etch from one side,
A small concave hole is formed on this one surface side. Next, the resist on the one surface side was peeled off and removed, and the one surface on which the resist was removed was coated with an etching resistance agent containing epoxy resin, casein and a leveling agent as main components to form an etching resistance layer. After that, post-stage etching is performed from the other surface side, and a large concave hole communicating with the small concave hole formed from the one surface side is formed on the other surface side.

[0007]

As described above, as a conventional shadow mask manufacturing method, there is a method called a two-step etching method. In this two-step etching method, the other surface of the shadow mask material on which the resist is formed is protected, a small concave hole is formed on one surface side by etching (previous etching), and then one surface side After the etching resistance layer is formed on the substrate, a large concave hole communicating with the small concave hole on the one surface side is formed on the other surface side (post-stage etching). In other words, this 2
In the step etching method, it is necessary to protect one surface side where a small concave hole was previously formed so as not to be etched at the time of the subsequent etching. Conventionally, the etching resistance for protecting the one surface side is required. Layers, epoxy resin,
It is formed by applying an etching resistance agent containing casein and a leveling agent as main components.

However, when the etching resistance layer containing an epoxy resin as a main component is formed in this manner, a large concave hole communicating with a small concave hole on one surface side is formed on the other surface side to form an electron beam passage hole. After that, there is a problem that it is difficult to remove the etching resistant layer, and the electron beam passage hole is easily clogged. That is, a high temperature caustic solution is used for peeling the etching resistance layer, but the epoxy resin is insoluble in the caustic alkali solution, so it is not completely peeled off, and the peeled etching resistance layer is in solution. And float on the flat mask to block the electron beam passage hole. Further, the peeled etching resistance layer adheres to the inner wall of the peeling chamber, the roller, etc., and clogs the electron beam passage hole.

Further, in the method of manufacturing a long strip shadow mask material while running, in order to prevent damage to the etching resistance layer due to contact with a running drive roller or guide roller, the etching resistance layer is subjected to high temperature heat treatment to Although it is desired to increase the hardness, the high temperature heat treatment further makes it difficult to peel off after the etching is completed, and the manufacturing yield of the flat mask is reduced.

As a method of solving the problem of the above-mentioned etching resistance layer that has been heat-treated at high temperature, a protective film similar to the one to be adhered to the other surface side is attached instead of the etching resistance layer at the time of the previous etching. Although there is a method, such a method has a higher manufacturing cost than the method of forming the etching resistance layer.

The present invention has been made in view of the above-mentioned problems, and the hardness of the etching resistance layer is increased to make it less likely to be damaged, and the etching resistance layer can be easily peeled off without lowering the etching resistance and the electron beam passage. It is an object of the present invention to obtain a method for manufacturing a shadow mask that is less likely to cause hole clogging.

[0012]

Means for Solving the Problems A resist having a pattern corresponding to an electron beam passage hole of a shadow mask is formed on both surfaces of a shadow mask material, and the shadow mask material on which the resist is formed is etched from one surface side. After forming the first concave hole on one surface side of the lever, the resist on the one surface side is peeled off, and an etching resistance agent is applied to the peeled one surface of the resist to form an etching resistance layer. After that, the shadow mask material is etched from the other surface side to form a second concave hole communicating with the first concave hole on the other surface side to form an electron beam passage hole. In the method for manufacturing the same, the etching resistance agent is a composition containing acrylic resin, casein and dichromate as main components, and the etching resistance agent is the first concave portion. There After forming the etching resistant layer is coated on one surface formed and cured by irradiation with ultraviolet rays.

Further, the content of the acrylic resin in the etching resistance agent is 3.0 to 7.0% by weight, the content of casein is 3 to 5% by weight, and the content of dichromate is 0.5 to 7. 1.
It was set to 5% by weight.

[0014] Also, the ultraviolet 365nm near the etch resistant layer is cured 150~500mJ / c ^m2 irradiating the.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 (a) to 1 (h) show the main steps of a method for producing a shadow mask by a photo-etching method, especially a two-step etching method.

As a shadow mask material, a plate thickness of 0.13
After degreasing and cleaning with an aluminum-killed steel plate of about mm,
As shown in FIG. 1A, this shadow mask material 20
A photosensitizer containing milk caseinate alkali and ammonium dichromate as main components is applied to both surfaces of the above and dried to form a photosensitive film 21 having a thickness of about 6 μm. Next, as shown in (b), a pair of negative masters 22 having the following patterns of different sizes corresponding to the electron beam passage holes of the shadow mask to be manufactured are formed on the photosensitive films 21 on both sides.
A and 22b are closely contacted and exposed, and the patterns of the negative master plates 22a and 22b are printed on the photosensitive films 21 on both sides. The pattern of the negative master 22a on the other hand is smaller than that of the relatively small first concave hole 12 of the electron beam passage hole 11 shown in FIG.
A slightly smaller pattern is formed in consideration of the side etching amount at the time of etching which will be described later. On the other hand, the pattern of the other negative original plate 22b is formed with a slightly smaller pattern than the relatively large second concave hole 12 in consideration of the side etching amount at the time of etching.

Next, the photosensitive films 21 on both sides of which the above-mentioned pattern has been baked are developed to remove the unexposed portion, and as shown in (c), a resist 23a consisting of a pattern corresponding to the above-mentioned pair of negative master plates. , 23b are formed. The pattern of the resists 23a and 23b is such that the electron beam passage hole forming portion is the opening portion 24a where the shadow mask material 20 is exposed.
, 24b, and the opening 24a on one surface side is formed relatively smaller than the opening 24b on the other surface side. The resists 23a and 23b may be burned in an atmosphere of about 200 ° C. for about 2 minutes, if necessary, in order to enhance etching resistance.

Next, as shown in (d), on the other surface side where the resist 23b having a relatively large opening portion 24b is formed, one made of polyethylene, polystyrene, vinyl chloride resin or the like is used. Thin protective film 2
6 is affixed with an adhesive, and a relatively small opening 24a
One surface on which the resist 23a having the is formed faces downward, and an etching solution containing ferric chloride as a main component is sprayed on the one surface to form a small concave hole 12 (first hole) in the opening 24a. (Concave hole) is formed (pre-stage etching).
Then, as shown in (e), both surfaces thereof were washed with water to wash away the etching solution, and then one side of the surface having the concave holes 12 was heated to 60 ° C. with a concentration of 15 wt. Spray a caustic solution such as an aqueous sodium solution,
The resist on one surface side is removed. After further washing with water, it is once dried.

Next, as shown in (f), one side of the resist which has been removed faces upward, and one side of which has acrylic resin, casein and dichromate as main components will be described later. The etching resistance agent is applied by, for example, a knife coater. Then, the protective film attached to the other surface side is peeled off to expose the other surface side where the resist 23b having the large opening portion 24b is formed. Then, the shadow mask material 20 is kept horizontal and the applied etching resistance agent is dried to form the etching resistance layer 28. If the drying temperature of this etching resistance agent is low, the strength is weak, and on the contrary, if it is too high, peeling and removal becomes difficult, and therefore 80 to 150 ° C., preferably 100 to
Dry at 120 ° C. By this drying, the volume of the solvent in the applied etching resistance agent is reduced by evaporation, and a depression is formed in the concave portion.

Next, the dry etching resistance layer 28 is formed.
It is irradiated with ultraviolet rays and cured. The ultraviolet irradiation, using a high-pressure mercury lamp, by detecting the ultraviolet around 365nm by UV detector, to cure the etch resistant layer 28 is irradiated such that the integrated quantity of light 150~500mJ / c ^m2. This is because, if less than 150 mJ / c ^{m @ 2,} not the etching resistant layer 28 to a sufficient strength, also be irradiated 500 mJ / c ^{m @ 2} or more, the strength is not more strongly saturated.

Next, as shown in (g), the other surface side, on which the resist 23b having a large opening portion 24b is formed, faces downward, and the other surface has ferric chloride as a main component. Then, a large recessed hole 13 (second recessed hole) communicating with the small recessed hole is formed in the opening portion 24b by spraying the etching solution (second etching). After that, both surfaces are washed with water, then a caustic solution is sprayed, the resist and the etching resistant layer on the other surface side are dissolved and peeled off, further washed with water, and dried, as shown in (h).
A flat mask 29 having an electron beam passage hole 11 in which the concave hole 12 on one surface side and the concave hole 13 on the other surface side communicate with each other is obtained.

The shadow mask incorporated in the color cathode ray tube is formed by annealing the flat mask 29, press-molding it into a mask body having a predetermined shape, and further forming a black oxide film on the surface of the mask body, which is then separately formed on this mask body. It is manufactured by welding the mask frame thus prepared.

The etching resistance agent of this example for forming the etching resistance layer 28 is composed of a solution containing acrylic resin, casein and dichromate as main components.

The acrylic resin is a polymer of acrylic acid ester, a polymer of methacrylic acid ester, or a copolymer thereof, such as polymethyl acrylate, polyethyl acrylate, n-butyl polyacrylate, poly Methyl methacrylate, polyethyl acrylate, polybutyl acrylate, etc. are used.

Casein is a phosphoprotein contained in milk in an amount of about 3%, and normally forms a complex with calcium in milk and exists as colloidal particles. This casein is not a single protein but a complex protein of three kinds of α-casein, β-casein and γ-casein, and as a sensitizer, FR-15 and FR-1 manufactured by Fuji Yakuhin Kogyo Co., Ltd.
6, FR-17, manufactured by Intec, MR-SG, MR-
There are SGM, MR-SLG, etc., and 10 to 14% of casein is contained as solid content. For the etching resistance layer 28, such a photosensitizer containing casein can be used.

Ammonium dichromate and sodium dichromate are suitable as the dichromate.

For the etching resistance layer 28, a solution containing 3.0 to 7.0% by weight of the acrylic resin, 3 to 5% by weight of casein, and 0.5 to 1.5% by weight of dichromate is used. To be If the acrylic resin content is less than 3.0% by weight outside this composition, the adhesion to the shadow mask material and the etching resistance will deteriorate. On the other hand, 7.0
If it exceeds the weight%, it becomes difficult to completely peel and remove in the peeling step after etching. If the casein content is less than 3% by weight, it becomes difficult to completely remove the peeling in the peeling step after etching. On the other hand, if it exceeds 5% by weight, the adhesion to the shadow mask material and the etching resistance deteriorate. Further, the content of dichromate is 0.
If it is less than 5% by weight, the etching resistance layer is insufficiently cured by ultraviolet rays and is easily scratched. On the other hand, 1.
When it exceeds 5% by weight, the etching resistance layer 28 gels and cannot be used.

Next, the etching process in the above shadow mask manufacturing method will be described in more detail.

FIG. 2 shows an apparatus used for the etching. This etching system has resists 23a on both sides,
23b is formed, and has a long strip-shaped shadow mask material 20 wound in a hoop shape, and has a transport mechanism (not shown) for feeding and running, and then winding, and a shadow mask material that is run by this transport mechanism. A plurality of chambers 31a to 31i are provided along the traveling route of 20. Further, along the traveling path of the shadow mask material 20, a protective film 26 to be attached to the other surface side of the shadow mask material 20 on which the resist 23b having a relatively large opening is formed is supplied and attached. A protective film supply / winding mechanism 32 is provided for peeling and winding the thus-protected protective film 26 before the subsequent etching.

The etching by this etching apparatus is performed by the long strip-shaped shadow mask material 2 wound in the hoop shape.
0 is continuously sent with one surface side on which the resist 23a having a relatively small opening is formed facing downward, and first, the protective film supply / winding mechanism 32 is provided on the other surface side.
The protective film 26 supplied by the above is attached. After that, it is carried into the first chamber 31a, and the etching liquid is sprayed from a plurality of spray nozzles 33 provided in the lower portion of the first chamber 31a to form a relatively small concave hole on one surface facing downward. Yes (pre-stage etching). Then, it is carried into the second chamber 31b adjacent to the first chamber 31a, and water is sprayed from a plurality of spray nozzles 34 provided in the upper and lower parts of the second chamber 31b to wash away the etching solution. Then, it is carried into the third chamber 31c adjacent to the second chamber 31b, and a 15% solution of sodium hydroxide is sprayed from a plurality of spray nozzles 35 provided in the lower portion of the third chamber 31c to form the above-mentioned concave portion. The resist 23a on one surface where the holes are formed is peeled and removed. Then this third
It is carried into the fourth chamber 31d adjacent to the chamber 31c, sprayed with water from a plurality of spray nozzles 36 provided in the upper and lower parts of the fourth chamber 31d for cleaning, and further dried by a heater (not shown).

After that, the surface of the shadow mask material 20 is reversed by the transport rollers 38 and 39, and the resist 23 is removed.
After facing up one side of a that has been peeled and removed,
The fifth chamber 31e is loaded into the chamber 31e.
An etching resistance agent is applied by a knife coater 40 installed inside. After that, the protective film 26 attached to the other surface side is attached to the protective film supply / winding mechanism 32.
Peel off and wind up. Then, the shadow mask material 20 from which the protective film 26 has been peeled off is placed in the sixth chamber 31.
After being carried in f, the etching resistance agent applied to the one surface is dried by the heater 41 installed in the sixth chamber 31f to form an etching resistance layer. After that, it is carried into the seventh chamber 31g adjacent to the sixth chamber 31f, and the etching resistance layer is irradiated with ultraviolet rays from the high-pressure mercury lamp 42 installed above the seventh chamber 31g to be cured. In this seventh chamber 31g, the shadow mask material 2 traveling at a predetermined speed is used.
In order to keep the amount of ultraviolet rays applied to 0 constant, a detector for detecting the deterioration of the intensity of the emitted ultraviolet rays and the disconnection of the lamp 42 is provided. For the deterioration of the ultraviolet intensity, the voltage is switched by a step switch or the like. Keep UV intensity constant, and spare lamp (not shown) for disconnection
It has a structure that lights up.

Then, it is carried into the eighth chamber 31h adjacent to the seventh chamber 31g, and a plurality of spray nozzles 4 provided under the eighth chamber 31h.
An etching solution is sprayed from 3 to form a relatively large concave hole communicating with the relatively small concave hole formed on the one surface side on the other downward surface (etching in the latter stage). Then, it is carried into the ninth chamber 31i adjacent to the eighth chamber 31h, and the plurality of spray nozzles 4 provided at the upper and lower parts of the ninth chamber 31i are loaded.
4. Water is sprayed from 4 to wash away the etching solution. After that, it is carried into a tenth chamber (not shown) adjacent to the ninth chamber 31i, and a plurality of spray nozzles provided in the upper and lower parts of the tenth chamber are used to remove the third
A caustic alkali solution similar to the sodium hydroxide solution in the chamber 31c is sprayed to remove the resist 23b on the other surface having the relatively large concave hole and the etching resistance layer formed on the one surface side. Remove. Then, it is carried into an 11th chamber (not shown) adjacent to the 10th chamber, and sprayed with water from a plurality of spray nozzles provided in the upper and lower parts of the 11th chamber to wash it, and then the next chamber. 11. Load into a chamber (not shown) and dry.

By the way, as described above, after forming a concave hole on one surface of the shadow mask material by the preceding etching, an acrylic resin, casein and dichromate are formed on the one surface where the concave hole is formed. Is applied to form an etching resistance layer, and the etching resistance layer is irradiated with ultraviolet rays and cured to form a scratch resistant etching resistance layer. The occurrence of hole defects can be prevented. Moreover, since the acrylic resin dissolves in the caustic solution, the conventional epoxy resin, casein, and the leveling agent, which are the main problems of the etching resistance layer, are easily peeled off. Can be completely peeled off with a solution. Further, it is possible to almost completely eliminate the clogging of the electron beam passage hole due to the adhesion of the peeled etching resistance layer, and it is possible to manufacture a desired shadow mask with a high yield.

In the above embodiment, the etching resistance agent was applied by a knife coater, but the etching resistance agent may be applied by another method such as spraying, dipping, roller coating or bar coating. .

Further, in the above embodiment, the protective film attached to the other surface of the shadow mask material was peeled off after application of the etching resistance agent during the etching before forming the concave hole on the one surface of the shadow mask material. This protective film may be peeled off before application of the etching resistance agent, that is, after removing the resist on one surface side, washing with water and drying.

In the above embodiment, the etching resistance layer containing acrylic resin, casein and dichromate as the main components is applied to form the etching resistance layer.
It is optional to add other materials such as a leveling agent to the etching resistant layer.

Further, in the above embodiment, a relatively small concave hole is first formed on one surface side of the shadow mask material, and then a relatively large concave hole is formed on the other surface side. The invention can be applied to the case where a relatively large concave hole is first formed on the other surface side of the shadow mask material and then a relatively small concave hole is formed on the one surface side.

[0039]

As described above, after forming a concave hole on one surface of the shadow mask material by the preceding etching, an acrylic resin, casein and dichromate are formed on the one surface where the concave hole is formed. When an etching resistance layer containing as a main component is applied to form an etching resistance layer and the etching resistance layer is irradiated with ultraviolet rays and cured, an etching resistance layer having high hardness and less scratches can be formed. It is possible to prevent the occurrence of hole defects in the passage holes. Moreover, since the acrylic resin dissolves in the caustic solution, the conventional epoxy resin, casein, and the leveling agent, which are the main problems of the etching resistance layer, can be easily peeled off. Can be completely peeled. Further, it is possible to almost completely eliminate the clogging of the holes due to the adhesion of the peeled etching resistance layer, and it is possible to manufacture a desired shadow mask with a high yield.

[Brief description of drawings]

1A to 1H are views for explaining a method of manufacturing a shadow mask by a two-step etching method which is an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a case where a long strip shadow mask material is etched by an etching device.

FIG. 3 is a diagram showing a configuration of a color CRT.

FIG. 4 is a diagram showing a shape of an electron beam passage hole of a shadow mask of a color cathode ray tube.

[Explanation of symbols]

 11 ... Electron beam passage hole 12 ... Relatively small concave hole 13 ... Relatively large concave hole 20 ... Shadow mask material 21 ... Photosensitive film 23a, 23b ... Resist 24a, 24b ... A pair of negative master plates 26 ... Protective film 28 ... Etching resistance layers 31a to 31i ... Chamber 40 ... Knife coater 41 ... Heater 42 ... High pressure mercury lamp

Claims (3)

[Claims] 1. A resist having a pattern corresponding to an electron beam passage hole of a shadow mask is formed on both sides of a shadow mask material, and the shadow mask material on which the resist is formed is etched from one surface side to form a resist. After forming the first concave hole on the surface side, the resist on the one surface side is peeled off, and an etching resistance agent is applied to the peeled one surface of the resist to form an etching resistance layer. A shadow mask for a color cathode ray tube, wherein a shadow mask material is etched from the other surface side to form a second concave hole communicating with the first concave hole on the other surface side to form the electron beam passage hole. In the manufacturing method, the etching resistance agent is a composition mainly containing acrylic resin, casein and dichromate, and the etching resistance agent is Of after the recessed hole has been applied to one surface formed to form an etching resistant layer, the manufacturing method of a shadow mask for a color picture tube, characterized in that is cured by irradiation with ultraviolet rays. 2. The etching resistance agent has an acrylic resin content of 3.0 to 7.0% by weight and a casein content of 3%.
The method for producing a shadow mask for a color cathode ray tube according to claim 1, wherein the content of the dichromate is 0.5 to 1.5% by weight, and the content of dichromate is 0.5 to 1.5% by weight. 3. A process according to claim 1 or 2 color CRT shadow mask, wherein the etching resistant layer 150~500mJ / c ^m2 ultraviolet rays in the vicinity of 365nm to.