JPH11219656A - Method and device for manufacturing shadow mask for color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a high precise shadow mask of fine grade by eliminating thermal fogging. SOLUTION: A pair of photo-masks 12a equipped with a pattern corresponding to apertures in a shadow mask are put in tight attachment to photo-resists formed on both surfaces of a metal thin plate 10 and subjected to a photo- exposure, and the patterns of photo-masks are baked fast onto the photo-resists followed by a developing process so that resists consisting of patterns corresponding to the shadow mask apertures are formed on both surfaces of the metal thin plate. After exposure, cooling rollers 19 are immediately put in tight attachment to the photo-resists on these surfaces with patterns baked fast, followed by a cooling process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a shadow mask for a color cathode ray tube and an apparatus for manufacturing the same, and more particularly to a method of manufacturing a shadow mask for a color cathode ray tube which suppresses thermal fogging of a photoresist after exposure and an apparatus for manufacturing the same. About.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, a color cathode ray tube faces a phosphor screen 2 composed of a three-color phosphor layer formed on an inner surface of a panel 1 constituting an envelope.
A shadow mask 3 having a large number of apertures formed in a predetermined arrangement is disposed inside thereof, and the three electron beams 5B, 5G, 5R emitted from the electron gun 4 by the apertures are selected.
The three-color phosphor layer is formed so as to be correctly incident on the three-color phosphor layer.

Conventionally, the shadow mask 3 has been manufactured by a photo-etching method. That is, a photosensitizer is applied to both sides of a thin metal plate made of a low-carbon steel plate or the like to form a photoresist, and then a pair of a glass dry plate in which a pattern corresponding to the opening of the shadow mask is formed on the photoresist on both sides. Adhere the optical mask of
The photoresist on both sides is simultaneously exposed through this optical mask, and the pattern of the optical mask is printed on the photoresist on both sides. Next, the photoresist on which the pattern is baked is developed to remove unexposed portions, and a resist having a pattern corresponding to the opening of the shadow mask is formed on both surfaces of the thin metal plate. Thereafter, an etching solution is sprayed on both surfaces of the metal sheet on which the resist is formed, and an opening is formed by etching to manufacture the metal sheet.

In the manufacture of the above-mentioned shadow mask 3, a photosensitive agent mainly containing milk caseinate and ammonium dichromate (ADC) is generally used. On the other hand, an exposure light source for printing an optical mask pattern is used. For example, a mercury lamp that generates ultraviolet rays is widely used.

However, when the above-mentioned photosensitizer and exposure light source are used, there is a problem that a photosensitizer mainly containing milk alkali caseinate and ADC is exposed to heat and fogged. On the other hand, since a mercury lamp emits a large amount of light in the infrared region as well as light in the ultraviolet region, there is a problem in that the photoresist is heated by the irradiation of the infrared light and causes thermal fogging.

As a method of preventing this heat fogging, a method of arranging a filter for cutting off infrared rays can be considered. This method reduces not only infrared rays but also ultraviolet rays effective for baking a pattern, and has a predetermined exposure dose. Takes a long time to obtain, and the productivity is reduced. Therefore, usually, the exposure is reduced by an amount corresponding to hot fogging from the exposure required for forming a resist having a pattern corresponding to the opening of the shadow mask, or the addition of ADC to milk alkali caseinate is performed. Shadow masks are manufactured by methods such as reducing the amount to reduce the sensitivity of the photoresist.

However, when a shadow mask is manufactured by such a method, the fine pitch shadow mask of a high-definition color cathode-ray tube incorporated in a display device such as a computer tends to have a smaller opening size. The influence of heat fogging on the hole size is large, and the variation in the hole size is large. Therefore, not only is it difficult to produce a required shadow mask, but also the white uniformity of the color CRT is deteriorated.

[0008]

As described above, the shadow mask of the color cathode ray tube is formed by applying a photosensitive agent mainly composed of milk alkali caseinate and ADC to both surfaces of a thin metal plate to form a photoresist. A pair of optical masks with a pattern corresponding to the opening of the shadow mask are closely attached to the photoresist on both sides, exposed using a mercury lamp as an exposure light source, and printed by printing the pattern of the optical mask on the photoresist on both sides Have been.

However, when the above-mentioned photosensitizer and exposure light source are used, the photosensitizer mainly composed of milk milk alkali caseinate and ADC has a problem that the photosensitization proceeds due to heat and heat fogging occurs. On the other hand, since a mercury lamp emits a large amount of light in the infrared region as well as light in the ultraviolet region, there is a problem in that the photoresist is heated by the irradiation of the infrared light and causes thermal fogging.

[0010] Therefore, conventionally, the exposure amount is reduced by an amount corresponding to the heat fogging from the exposure amount required for forming a resist having a pattern corresponding to the opening of the shadow mask, or the exposure to milk caseinate is carried out. A
A shadow mask is manufactured by a method such as reducing the amount of DC to reduce the sensitivity of the photoresist.

However, in such a method, the effect of heat fogging on the aperture size is large and the variation in the aperture size is large for a high-definition shadow mask of a color CRT incorporated in a display device such as a computer. . Therefore, there is a problem that not only is it difficult to manufacture a required shadow mask, but also the white uniformity of the color CRT is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to make it possible to easily manufacture a high-definition high-definition shadow mask without heat fogging.

[0013]

A pair of optical masks each having a pattern corresponding to the opening of a shadow mask are brought into close contact with a photoresist formed on both sides of a thin metal plate, and the photoresist is exposed to an optical mask. In the method of manufacturing a shadow mask for a color cathode-ray tube, which develops after baking the pattern, and forms a resist having a pattern corresponding to the openings of the shadow mask on both surfaces of the metal thin plate,
Immediately after the exposure, a cooling roller was brought into close contact with the photoresist on both sides on which the pattern was baked to cool.

[0014] Further, a burning frame for supporting a pair of optical masks on which a pattern corresponding to the opening of the shadow mask is formed, and bringing the pair of optical masks into close contact with the photoresist formed on both surfaces of the strip-shaped thin metal plate; An exposure light source for printing an optical mask pattern on the photoresist, and a winding device for winding a strip-shaped thin metal plate having the optical mask pattern printed on the photoresist, a shadow mask manufacturing apparatus for a color cathode-ray tube. A cooling roller was provided on the winding device side close to the frame to closely contact and cool the photoresist on which the pattern was baked.

[0015]

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

FIG. 1 shows the main steps of a method of manufacturing a shadow mask for a color CRT, which is one embodiment of the present invention.

As shown in FIG. 1A, a shadow mask is manufactured by degrease and cleaning a strip-shaped metal sheet 10 made of a low-carbon steel sheet having a thickness of about 0.1 to 0.3 mm, and then applying milk on both sides thereof. A photosensitive agent mainly composed of alkali caseinate and ammonium bichromate (ADC) is applied and dried to form a photoresist 11.

Next, as shown in FIG. 2B, a pair of glass dry plates in which patterns having different sizes corresponding to the openings of the shadow mask to be formed are formed in the photoresist 11 on both surfaces. Optical masks 12a, 12
b, and the photoresist 11 on both sides is simultaneously exposed through the optical masks 12a and 12b by light emitted from an exposure light source 13 composed of a mercury lamp provided in front of the optical masks 12a and 12b. The patterns of the optical masks 12a and 12b are printed on the resist 11.

Next, the photoresist 11 on which the pattern has been baked is developed with warm water to remove the unexposed portions, and as shown in FIG. Resists 14a and 14b having corresponding patterns are formed.

Next, the resists 14a and 14b are
After burning at a temperature of about 00 ° C. to enhance the etching resistance, an etching solution containing ferric chloride as a main component is sprayed on both surfaces of the strip-shaped metal sheet 10 to form a resist 14a.
, 14b are etched to form openings 15 as shown in FIG.

Next, a heated alkali solution is sprayed on both sides of the strip-shaped metal sheet 10 having the openings 15 formed therein,
As shown in (e), the resist remaining on both surfaces of the strip-shaped metal sheet is peeled off.

In the above method of manufacturing a shadow mask,
Photoresist 1 formed on both sides of strip-shaped metal sheet 10
The pattern printing on No. 1 is performed by the apparatus shown in FIG.

This apparatus comprises optical masks 12a and 12b.
A vacuum firing frame 16 is provided for supporting the optical masks 12a and 12b on the photoresist on both sides of the strip-shaped metal sheet 10 (see FIG. 1). An exposure light source (not shown) composed of a mercury lamp is provided in front of the optical masks 12a and 12b supported by the vacuum furnace 16. Further, on one side of the vacuum furnace 16, a roll 1 of a strip-shaped metal sheet 10 having a photoresist formed on both sides is provided.
A rewinding device (unwinder portion) supporting the roll 7 and a roll-up device supporting the roll 18 of the strip-shaped sheet metal 10 having a pattern printed on the photoresist on both sides by the vacuum printing frame 16 on the other side. (Winder section) is provided.

The printing of the pattern by this device is performed by intermittently driving the winding device to rotate the roll 1 supported by the winding device.
8 is rotated, and the strip-shaped metal sheet 1 guided from the roll 17 supported by the rewinding device to the winding device via the vacuum firing frame 16.
0 is wound up to a fixed length. During the winding stop period, the optical mask 1 is applied to the photoresist on both sides of the strip-shaped thin metal sheet 10 guided from the roll 17 supported by the rewinding device to the vacuum furnace 16.
The optical masks 12a and 12b are brought into close contact with each other by vacuum.
a, 12b are printed, and the optical masks 12a, 1b are sequentially applied to the photoresist on both sides of the strip-shaped metal sheet 10 by intermittent driving of the winding device.
The pattern 2b is to be printed.

In such an apparatus, in this embodiment, in particular, in this embodiment, a pair of close-contacting photoresists on both sides of the pattern printed by the vacuum printing frame 16 are provided close to the vacuum printing frame 16 on the winding device side. A set of cooling rollers 19 is provided. The cooling roller 19 is cooled by cooling air of about 14 ° C., rotates with the running of the strip-shaped metal sheet 10 due to the intermittent rotation of the roll 18, and adheres to the photoresist on both sides where the pattern is baked. Then, at the time of pattern printing, the photoresist heated by the irradiation of infrared rays emitted from the exposure light source is cooled.

Normally, the temperature of the roll 17 of the strip-shaped metal sheet 10 supported by the rewinding device is 23 to 26 ° C., and the vacuum furnace 16 is heated to 35 ° C. or higher by the irradiation of infrared rays emitted from the exposure light source. As described above, the cooling roller 19 is provided on the rewinding device side close to the vacuum printing frame 16 as described above, and is brought into close contact with the photoresist on both surfaces. , The temperature of the strip-shaped metal sheet 10 wound by the winding device can be set to 30 to 35 ° C., which is safe against heat fogging.

Therefore, by performing the above,
Even if it is heated at the time of exposure, it can be set to a temperature at which thermal fogging is unlikely to occur due to cooling immediately thereafter. As a result, it is possible to produce a shadow mask without reducing the exposure amount by the amount corresponding to the heat fogging as before, or to manufacture a shadow mask without lowering the sensitivity of the photoresist. By applying this, it is possible to reduce the variation in the aperture size and prevent the white uniformity of the color CRT from deteriorating.

In the above embodiment, one set of cooling rollers is provided on the winding device side of the vacuum furnace, but a plurality of sets of cooling rollers may be provided.

Further, it may be provided not only on the winding device side of the vacuum forming frame but also on the rewinding device side close to the vacuum forming frame.
In this manner, the temperature of the photoresist during pattern baking can be reduced.

Further, in addition to the cooling roller, other cooling means such as blowing cooling air directly onto the photoresist on which the pattern has been printed may be used in combination.

In the above embodiment, a method of manufacturing a shadow mask in which openings are formed by simultaneously etching both sides of a strip-shaped thin metal plate on which a resist is formed has been described. The present invention is also applicable to a case where an opening is formed by etching one surface at a time.

[0032]

As described above, a cooling roller is provided close to a printing frame for printing a pattern on a photoresist formed on both surfaces of a strip-shaped metal sheet, and is closely attached to the printed photoresist of the optical mask pattern. Immediately after cooling, the exposure can be reduced by the amount corresponding to the heat fogging as in the past, or the shadow mask can be manufactured without lowering the sensitivity of the photoresist. By applying a fine pitch shadow mask for a cathode ray tube, variations in the opening size can be reduced, and deterioration of the white uniformity of the color cathode ray tube can be prevented.

[Brief description of the drawings]

FIGS. 1A to 1E show main steps of a method of manufacturing a color CRT shadow mask according to an embodiment of the present invention.

FIG. 2 is a view showing a configuration of an apparatus for printing a pattern of an optical mask on a photoresist formed on both sides of a strip-shaped metal sheet.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Strip metal sheet 11 ... Photoresist 12a, 12b ... Optical mask 13 ... Exposure light source 14a, 14b ... Resist 15 ... Opening 16 ... Burning frame 19 ... Cooling roller

Claims (2)

[Claims] 1. A pair of optical masks each having a pattern corresponding to an opening of a shadow mask are brought into close contact with a photoresist formed on both sides of a thin metal plate and exposed, and the pattern of the optical mask is applied to the photoresist. Developing after baking, in a method of manufacturing a shadow mask for a color cathode-ray tube in which a resist having a pattern corresponding to the opening of the shadow mask is formed on both surfaces of the metal sheet, the pattern was baked immediately after the exposure. A method of manufacturing a shadow mask for a color cathode-ray tube, wherein a cooling roller is brought into close contact with the photoresist on both sides and cooled. 2. A baking frame for supporting a pair of optical masks on which a pattern corresponding to the opening of the shadow mask is formed, and bringing the pair of optical masks into close contact with photoresist formed on both surfaces of the strip-shaped metal sheet; An exposure light source for printing the pattern of the optical mask on the photoresist, and a shadow mask manufacturing apparatus for a color cathode-ray tube including a winding device for winding a belt-shaped metal sheet on which the pattern of the optical mask is baked on the photoresist, An apparatus for manufacturing a shadow mask for a color cathode-ray tube, wherein a cooling roller is provided on the winding device side close to the burning frame to cool the photoresist in close contact with the photoresist having the pattern printed thereon.