JP2001222953A - Sealing method and jig for cathode-ray tube electron gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To firmly seal an electron gun in a cathode-ray tube, using a butt seal system, without any damage to the electron gun stem in spite of being exposed to a thermal shock. SOLUTION: The sealing method for the cathode-ray tube electron gun specifies that, under the condition that the electron gun with a glass-made stem is supported by a part of a cylindrical sealing jig and that at least the part of the electron gun is inserted inside the glass-made neck of the cathode-ray tube, the electron gun stem is heated preliminarily and then both the preliminarily heated stem and neck are heated and welded. In this case, the preliminary heating of the stem is done by exposing a flame to the sealing jig itself and utilizing the heat conduction from the heated sealing jig.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to sealing an electron gun for a cathode ray tube such as a color picture tube, and more particularly to a method and a jig for sealing a cathode ray tube by a butt seal method.

[0002]

2. Description of the Related Art Generally, in a cathode ray tube, after arranging various tube members in an envelope, an electron gun is sealed in a neck of the envelope, and thereafter, processes such as exhaust, finishing, and inspection are performed. Manufactured through As an example, FIG. 4 shows a configuration of a color picture tube, and FIG. 5 shows a method of manufacturing the color picture tube.

In the manufacture of this color picture tube, a phosphor screen 2 is formed on an inner surface of a glass panel 1 constituting a front portion of an envelope, and a shadow mask is formed on the panel 1 on which the phosphor screen 2 is formed. 3 is installed. On the other hand, an inner conductive film 5 is applied and formed on the inner surface of the glass funnel-shaped funnel 4 which forms the envelope together with the panel 1.
The frit glass is applied to the end face of the large diameter portion to be joined to the panel 1. Next, the panel 1 is positioned on the funnel 4, and the panel 1 and the funnel 4 are heated.
Bonding is performed using the frit glass (sealing step). Next, a stem-equipped electron gun 9 in which a glass stem 8 assembled in an electron gun assembling process is mounted in a neck 6 of an envelope composed of the joined panel 1 and funnel 4 is sealed. . Next, the sealed envelope of the electron gun 7 is evacuated while being heated. After that, the electron gun 7 is manufactured by performing a finishing treatment such as activation of a cathode of the electron gun 7 and a high voltage treatment for increasing a withstand voltage, and inspection.

As a method for sealing the electron gun 7, there is a method called a butt seal method. In this sealing method, the end side of the neck 6 of the envelope composed of the panel 1 and the funnel 4 joined in the sealing step is cut to a predetermined size in advance, while FIG. As shown, an electron gun 9 with a stem is supported by a cylindrical sealing jig 10, and the electron gun 9 is inserted into the neck 6 cut to the above-mentioned predetermined size, and the stem 8 is attached to the end of the neck 6. Position it inside. Then, the sealing jig 10 is heated by a heater 11 made of a nichrome wire arranged on the outer periphery of the sealing jig 10 to indirectly preheat the stem 8 by heat conduction, and is arranged on the outer periphery of the neck 6. The neck 6 is preheated by a heating tool 12 such as a radiant burner. Then, (b)
As shown in (1), the end of the neck 6 is heated and softened by the high-temperature flame 14 from the burner 13 disposed outside the sealing portion, and the stem 8 and the end of the neck 6 are welded. Thereafter, the cooling is performed gradually to remove the strain.

As another butt-seal method, as shown in FIG. 7, an electron gun 9 with a stem is supported on a cylindrical sealing jig 10, and the electron gun 9 is cut into a predetermined size. And the stem 8 is positioned in contact with the end face of the neck 6. Thereafter, a sealing method similar to the above sealing method is disclosed in Japanese Patent Application No. 11-9128.
No.

[0006]

As described above, as a method of sealing an electron gun for a cathode ray tube, an electron gun with a stem is supported on a sealing jig, and the electron gun is cut into a predetermined size of an envelope. The sealing jig is heated by a heater consisting of a nichrome wire placed on the outer periphery of the sealing jig. Preheating the stem indirectly, preheating the neck with a heating tool such as a radiant burner placed on the outer periphery of the neck, and then heating the end of the neck with a high-temperature flame from the burner placed outside the sealing section There is a method called a butt seal method in which an electron gun is sealed by softening and welding a stem and a neck end.

[0007] Among the sealing methods using the butt seal method, in particular, in the sealing method in which the stem is brought into contact with the end face of the neck, a high-temperature flame from the burner is directly applied to the stem. However, there is a problem that it is easy to cause crash destruction.

As a result of analysis, as shown in FIG. 8, the stem 8 has a fillet 17 provided around a plurality of metal wires 16 penetrating the flare 15. This is because the heat capacity of the outer periphery of the flare 15 welded to the neck is extremely small with respect to the provided portion, and the high-temperature flame from the burner directly hits the stem 8 due to the difference in heat capacity, which causes a thermal shock. I understand.

That is, even in the same butt seal method, in the method of sealing with the stem positioned inside the neck end, the high-temperature flame from the burner does not directly hit the stem, but the high-temperature flame from the burner causes the neck end. The part is melted and softened and contracted, and is sealed by contacting and welding with the stem. In this case, since the temperature of the melt-softened glass at the neck end is about 1000 ° C., if the stem is preheated to about 300 ° C., the temperature difference from the neck end can be maintained at about 700 ° C. Even if it receives a thermal shock, it can be sealed without reducing the generated thermal stress and causing breakage.

However, in the method of sealing by bringing the stem into contact with the end face of the neck, as described above, the high-temperature flame from the burner directly hits the stem and receives a thermal shock of about 3000 ° C. Therefore, even if the stem is preheated, the temperature difference from the flame from the burner is extremely large, and the resulting thermal stress exceeds the impact strength due to the complicated structure of the stem, and fillets around the metal wire. Crash destruction starts from the vicinity of the boundary between the portion provided with the flare and the outer peripheral portion of the flare welded to the neck.

Therefore, in the method of sealing by bringing the stem into contact with the end face of the neck, it is necessary to prevent a large thermal shock from being applied to the stem even when the high-temperature flame from the burner directly hits the stem.

The present invention has been made in view of the above problems, and in a method of sealing a cathode ray tube with an electron gun by a butt seal method, a stem can be stably sealed without being damaged even when subjected to a thermal shock. The purpose is to be.

[0013]

(1) An electron gun with a glass stem is supported on one end of a cylindrical sealing jig, and at least the electron gun portion of the electron gun with a stem is made of a glass neck of a cathode ray tube. After the stem of the electron gun with the stem is preheated, the preheated stem and neck are heated and welded. The stem was heated by irradiating a flame, and the stem was preheated by heat conduction from the heated sealing jig.

(2) In the method of (1) for sealing an electron gun in a cathode ray tube, when the strain point of the glass constituting the stem is set to T ° C., the temperature of the stem is set to T ° C.−5 at the start of welding to the neck.
Preheating was performed until the temperature reached 0 ° C. or higher.

(3) In the method for sealing an electron gun of a cathode ray tube according to (1), a plurality of burners are radiated to the outer periphery of the sealing jig from a direction inclined in a radial direction or a lateral direction. It was arranged to heat the sealing jig.

(4) In the method for sealing an electron gun of a cathode ray tube according to (1) or (3), the axial direction of the sealing jig in the axial direction of the sealing jig is set with respect to one end of the sealing jig supporting the electron gun with a stem. ~ 2
The flame from the burner was irradiated within a range of 0 mm.

(5) An electron gun with a glass stem, which is sealed in the neck of a cathode ray tube, is supported at one end and is heated by irradiation of a flame from a burner, and the stem of the electron gun with the stem is heated by heat conduction. In the cylindrical sealing jig to be preheated, an overhang is provided on the outer periphery of one end supporting the electron gun with the stem, the outer diameter of the one end is A, the outer diameter of the overhang is B, and the overhang is On the other hand, when the outer diameter on the opposite side of the one end is C, B ≧ AB> C.

(6) In the sealing jig of (5), the projecting portion is provided within a range of 0 to 10 mm in the axial direction of the sealing jig from one end supporting the electron gun.

(7) In the sealing jig of (5) or (6), the overhang is formed to a thickness of 0.5 to 5 mm.

(8) In the sealing jig according to any one of (5) to (7), the outer diameter of the protruding portion is formed to be +6 to -3 mm with respect to the outer diameter of the stem.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a method of sealing a cathode ray tube with an electron gun by a butt seal method and a sealing jig thereof according to one embodiment will be described. In this embodiment,
The glass neck 6 of the cathode ray tube envelope is cut to a predetermined size. On the other hand, an electron gun 9 with a stem formed by attaching a glass stem 8 to the electron gun 7 is supported by a cylindrical sealing jig 20, and the electron gun 7 supported by the sealing jig 20 is placed in the neck 6. Then, the stem 8 is brought into contact with the end face of the neck 6.
Then, the sealing jig 20 is heated by a flame 22 from a burner 21 disposed on the outer periphery thereof, and the stem 8 is indirectly moved by heat conduction to the strain point (about 38
5 ° C.), that is, when the strain point of the glass constituting the stem 8 is T ° C., the preheating is performed to a temperature of T ° C.−50 ° C. or more, and the heating of a radiant burner or the like disposed around the neck 6 is performed. The end of the neck 6 is preheated by the tool 12. Next, both the stem 8 and the end of the neck 6 are heated and softened and welded by a high-temperature flame 14 from a burner 13 disposed outside the sealing portion between the preheated stem 8 and the end of the neck 6. Thereafter, the electron gun 7 is sealed by gradually cooling to remove distortion.

In this sealing method, the burner 21 for heating the sealing jig 20 is provided near one end of the sealing jig 20 supporting the electron gun 9 as shown in FIG. Are arranged in such a manner as to irradiate the flame 22 from a direction inclined in a radial direction or a lateral direction with respect to the outer periphery. As a gas for heating the sealing jig 20, a mixed gas of city gas or LP gas and oxygen, or hydrogen and oxygen is used.

As described above, the reason why the sealing jig 20 is heated by the flame 22 from the burner 21 is that, in the method in which the stem is brought into contact with the end face of the neck and the sealing is performed, the stem 8 and the end of the neck 6 are closed. The high-temperature flame 14 at the time of welding directly hits the stem 8 and is easily damaged by a thermal shock. In order to prevent the stem from being broken by the thermal shock, the stem may be preheated to a temperature near the strain point T ° C. of the constituent glass. However, the heating of the sealing jig for preheating the stem must also take into account the slow cooling after welding the stem and the neck end, so that the heat capacity of the sealing jig should be as small as possible. Need to be able to raise the temperature efficiently. For this reason, it is difficult for the conventional heating means such as a nichrome wire heater to satisfy both. However, when the heating is performed by the burner 21 as described above, the stem 8 can be efficiently preheated, and the gradual cooling after welding the stem and the neck end can also be efficiently performed.

The heating position of the sealing jig 20 by the burner 21 is such that the flame 22 from the burner 21 is directly
In order to suppress the thermal shock when hitting zero and preheat the stem efficiently, it is preferable that the range from one end supporting the electron gun 9 to the axial direction of the sealing jig 20 be 0 to 20 mm.

On the other hand, regarding the sealing jig 20, the flame 22
, The heat loss increases, and a thermal shock is applied to the stem 10. Therefore, as shown in FIG. 1, the sealing jig 20 is provided with an annular projecting portion 24 on the outer periphery on one end side, and the projecting portion 24 is provided on the opposite side of the one end portion from the burner 21. The flame 22 is irradiated. With this configuration, the thermal shock to the stem 8 due to the rising of the flame 22 can be reduced by the overhang portion 24, and the sealing jig 20 can be efficiently heated by heating the overhang portion 24. The rising of the flame 22 changes depending on heating conditions such as the size of the flame 22 and the irradiation angle of the flame 22 to the sealing jig 20.

More specifically, as shown in FIG. 3, the sealing jig 20 has an outer diameter of one end A, an overhang 2
When B is the outer diameter of C and the outer diameter of the overhanging portion 24 on the side opposite to the one end is C, B ≧ AB> C. The overhang portion 24 is preferably provided in a range of 0 to 10 mm from one end of the sealing jig 20. Further, the thickness of the overhang portion 24 may be about 0.5 to 5 mm. Further, the overhang portion 24 has +6 with respect to the outer diameter of the stem.
It is effective to form it into a size having an outer diameter B of about -3 mm.

The sealing jig 20 is constructed as described above, and is heated by the flame 22 from the burner 21. By heat conduction, the stem 8 is heated to T.degree. When preheating to the temperature, the stem 10
Abuts on the stem 8 due to thermal shock.
And the electron gun can be stably sealed.

In the above-mentioned embodiment, the case where the stem is brought into contact with the end face of the neck cut to a predetermined size to perform sealing is described. However, in the present invention, the stem is arranged inside the neck end. It can be applied to the case where sealing is performed, and the same effect can be obtained.

[0029]

As described above, when the sealing jig supporting the electron gun with the glass stem is heated by the flame from the burner and the stem is preheated by the heat conduction from the sealing jig, the heat is reduced. The electron gun can be stably sealed without breaking the stem due to the impact.

[Brief description of the drawings]

FIG. 1 is a view for explaining a method of sealing a cathode ray tube with an electron gun by a butt seal method according to an embodiment of the present invention. FIG. 1A is a view for explaining preheating of a stem and a neck. FIG. 1B is a view for explaining welding of the stem and the neck end after preheating.

FIGS. 2A and 2B are views showing the arrangement of a burner with respect to a sealing jig for preheating the stem.

FIG. 3 is a view for explaining the size of an overhang provided on the sealing jig.

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

FIG. 5 is a diagram for explaining a method of manufacturing a color picture tube.

6A and 6B are views for explaining a conventional method of sealing a cathode ray tube with an electron gun by a butt-seal method, and FIG. 6A is a view for explaining preheating of a stem and a neck;
(B) is a figure for demonstrating welding of the stem and neck end part after preheating.

FIG. 7 is a view for explaining an electron gun sealing method for different cathode ray tubes by a conventional butt seal method.

FIG. 8A is a plan view showing the structure of a stem, FIG.
(B) is a sectional view thereof.

[Explanation of symbols]

 6 Neck 7 Electron gun 8 Stem 9 Electron gun with stem 20 Sealing jig 21 Burner 22 Flame 24 Overhang

Claims (8)

[Claims] An electron gun with a glass stem is supported on one end of a cylindrical sealing jig, and at least an electron gun portion of the electron gun with a stem is inserted into a glass neck of a cathode ray tube. After preheating the stem of the attached electron gun, the preheated stem and the neck are heated and welded by an electron gun sealing method for a cathode ray tube, wherein the sealing jig is irradiated with a flame from a burner. A method for sealing a cathode ray tube with an electron gun, comprising heating and preheating the stem by heat conduction from the heated sealing jig. 2. When the strain point of the glass constituting the stem is T ° C., the temperature of the stem is set to T ° C.
2. The method according to claim 1, wherein preheating is performed until the temperature reaches 50 [deg.] C. or higher. 3. A method of heating the sealing jig by arranging a plurality of burners so as to irradiate a flame from a direction inclined in a radial direction or a lateral direction with respect to an outer periphery of the sealing jig. The method for sealing a cathode ray tube with an electron gun according to claim 1. 4. An end of the sealing jig supporting the electron gun with a stem is irradiated with a flame from a burner within a range of 0 to 20 mm in the axial direction of the sealing jig. Item 4. The method for sealing a cathode ray tube with an electron gun according to item 1 or 3. 5. An electron gun with a glass stem, which is sealed in the neck of a cathode ray tube, is supported at one end and is heated by the irradiation of a flame from a burner. In the cylindrical sealing jig to be heated, an overhang is provided on the outer periphery of one end supporting the electron gun with the stem, the outer diameter of the one end is B, the outer diameter of the overhang is B, and the overhang is B. A sealing jig characterized by: B ≧ A B> C where C is the outer diameter of the part opposite to the one end. 6. The sealing jig according to claim 5, wherein the overhanging portion is provided within a range of 0 to 10 mm in the axial direction of the sealing jig from one end supporting the electron gun. 7. The sealing jig according to claim 5, wherein the overhang is formed to a thickness of 0.5 to 5 mm. 8. The sealing jig according to claim 5, wherein an outer diameter of the overhang portion is formed to be +6 to −3 mm with respect to an outer diameter of the stem. .