JPH1040804A - Impregnation type cathode structure and manufacture thereof, oxide type cathode structure and manufacture thereof, electron gun structure, and electronic tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the strength deterioration in a welding portion and the thermal deformation of a cathode support body by forming the cathode support body of a high-melting point metal core material and metal material having lower melting point than that, and covering the fixing portion of the cathode support body and a cathode sleeve. SOLUTION: In an impregnation type cathode structure, a cathode support cylinder 25 is coaxially arranged outside a cathode sleeve 21. Plural cathode support bodies 26 are arranged inside the cathode cylinder 25 at positions, spaced at intervals in a circumference direction. The cathode support body 26 is composed of a core material 261 which is made of circular wire rods in cross sections, formed of high-melting point metal having strong high temperature strength, and covering material 262 which is formed, so as to cover the core material 261 and is made of metal having a lower melting point than that of the core material 261. The covering material 262 is fixed to one end of the cathode support body 26, and the core material 261 is fixed to the cathode sleeve 21. The core material 261 is selected from among W, Mo, Re, Ta, Nb, Ir or an alloy of these. The covering material 262 is selected from among Pt, Rh, Pd, V, Au, Ti or an alloy of these.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impregnated cathode structure used for an electron gun structure provided in an electron tube such as a color picture tube and a method of manufacturing the same, an oxide type cathode structure and a method of manufacturing the same, an electron gun structure and an electron tube. About.

[0002]

2. Description of the Related Art In recent years, a color picture tube, a large color picture tube, and the like which have increased resolution by increasing scanning lines as an electron tube,
The demand for cathode ray tubes (CRTs), such as high definition display tubes, is increasing. In an electron gun assembly provided in these cathode ray tubes (CRT), an impregnated cathode assembly and an oxide cathode assembly are used as cathodes.

[0003] The impregnated cathode structure in each of these cathode structures will be described. The impregnated type cathode structure has a feature that a larger current density can be obtained than an oxide cathode. However,
This impregnated cathode assembly has a problem that the operating temperature is higher than that of the oxide cathode assembly, and the heater power cannot be reduced.

FIG. 14 is a partially cutaway front view showing a conventional impregnated cathode assembly. The impregnated cathode assembly is mounted on an electron gun assembly (not shown), and further installed inside an electron tube.

[0005] A cup 3 having a cathode base 2 impregnated with an electron-emitting substance (emitter) is attached to one end of a cylindrical cathode sleeve 1. Cathode sleeve 1
Is formed of a metal such as Ta, Nb, Mo, and Re, or an alloy thereof. The cathode substrate 2 is, for example, a tungsten sintered body having a porosity of about 20% impregnated with an electron emitting material made of BaO, Al ₂ O ₃ , and CaO. The cup 3 is made of, for example, Ta, and is for preventing insulation deterioration of the heater 4 caused by the evaporation of the electron-emitting substance from the cathode base 2 scattered toward the heater 4 described later.

A heater 4 for heating the cathode base 2 is arranged inside the cathode sleeve 1, and the heater 4 is attached to a terminal attached to an electron tube (not shown).
The cathode substrate 2 is heated by the heater 4 to emit the impregnated electron emitting material. A cathode support cylinder 5 made of a cylindrical body is coaxially arranged outside the cathode sleeve 1. The cathode support cylinder 5 is made of, for example, Kovar (Fe—Ni—Co alloy), and has a longer length and a larger outer diameter than the cathode sleeve 1. One end of the cathode support tube 5 is formed with a shoulder 5a that is bent inward at a right angle in the entire circumferential direction, and a hole 5b is formed in a portion surrounded by the shoulder 5a. The cathode sleeve 1 has a hole 5b of the cathode support tube 5.
And the end having the cup 3 protrudes outward from the cathode support tube 5. The cathode support tube 5 is a cathode support tube 5
A fixing piece (not shown) is attached to the outer periphery of the fixing member, and the other end of the fixing piece is attached by being embedded in an insulating support (not shown).

A plurality of cathode supports 6 are arranged inside the cathode support tube 5 at circumferentially spaced positions.
The cathode support 6 is in the form of a ribbon extending in the axial direction of the cathode support tube 1, and one end thereof is protruded outside through the hole 5 b of the cathode support tube 5 and is fixed to the outer surface of the shoulder 5 a. The other end is fixed to the outer peripheral surface of the other end of the cathode sleeve 1. Each cathode support 6 is formed of, for example, the same material as the cathode sleeve 1. In order to attach the cathode support 6 to the cathode sleeve 1, laser welding is employed. That is, the cathode support 6 is irradiated with laser light, and the heat of the laser light partially melts the cathode support 6,
The molten portion flows and adheres to the surface of the cathode support tube 5 and solidifies, thereby fixing the cathode support 6 to the cathode support tube 5.

The manufacturing process for attaching the cathode support 6 to the cathode sleeve 1 is performed by the following method. First, a core metal mainly composed of copper is inserted into the inside of the cathode sleeve 1 to which the cup 3 is fixed at one end. Also,
The cathode support 6 is manufactured by cutting and molding the metal ribbon material into a certain size corresponding to the cathode support 6. Next, the cathode support 6 is fixed by a vacuum chuck, and is pressed against a fixing position on the outer peripheral surface of the cathode sleeve 1. afterwards,
The cathode support 6 is fixed to the surface of the cathode sleeve 1 by irradiating the cathode support 6 with laser light from a laser passage hole provided in the vacuum chuck section. Incidentally, laser welding is also employed as a means for attaching the cathode support 6 to the cathode support cylinder 5.

Next, the oxide type cathode structure will be described.
In general, an oxide cathode substrate having an electron emission material of an alkaline earth metal carbonate formed on a cathode substrate has a large electron emission ratio at a low operating temperature as compared with other types of cathodes, and has an arbitrary shape. Since it has many advantages such as easy acquisition and low cost, it is widely used for various electron tubes. On the other hand, it has a problem that it is difficult to obtain a high current density. Particularly, in recent years, further improvement has been desired since a high current density is required in a cathode ray tube.

FIG. 15 is a partially cutaway front view showing a conventional oxide cathode structure. The oxide type cathode structure shown in FIG. 15 is the same as the impregnated type cathode structure shown in FIG. 14 except for the structure of the cathode substrate. Therefore, in FIG. 15, the same portions as those in FIG. 14 are denoted by the same reference numerals. In FIG. 15, reference numeral 7 denotes a disk-shaped cathode substrate. On the surface of the cathode substrate 1, a layer of an electron emitting material 8 made of an oxide such as Ba, Sr, or Ca is formed.
The cathode base 7 is fitted into one end opening of the cathode sleeve 1 and fixed by laser welding.

The cathode sleeve 2 in this oxide type cathode structure is made of any one of Ni and an alloy containing Ni as a main component and an alloy containing Ni and Cr as a main component and a high melting point metal dispersed therein. It is formed by one or more kinds. The cathode sleeve 2 is made of a metal material having good weldability with Ni and N because the cathode sleeve 2 made of the metal material is fixed by performing laser welding on the cathode sleeve 2.
It is formed of at least one selected from alloys containing i as a main component.

[0012]

However, in each of such conventional impregnated-type cathode structures and oxide-type cathode structures, there are the following problems in fixing the cathode support 6 to the cathode sleeve 1. Have.

[0013] In the conventional impregnated cathode assembly, the component dimensions are set extremely small in order to reduce power consumption.
The dimensions of the cathode support are, for example, 0.3 mm in width and 0.03 in thickness.
It is as small as about mm.

The reason for reducing the size of the cathode support 6 in this way is as follows. During the operation of the cathode ray tube (CR #), the heat of the cathode sleeve 1 heated by the heater 4 and heated to conduct through the cathode support 6 and escape to the cathode support tube 5 to minimize the heat loss. Things.

However, when the cathode support 6 having such a small size is fixed to the cathode sleeve 1 by laser welding, the following problem occurs. That is, in performing laser welding, when the laser is irradiated to the cathode support 6 (ribbon) with a condensing diameter having a diameter larger than the width, the side edge of the cathode support 6 in the width direction is melted. As a result, the melted portion is pulled toward the center in the width direction of the cathode support 6 by surface tension, so that the cathode support 6 is thinned and the strength of the welded portion is deteriorated.

For this reason, when performing laser welding, it is necessary to irradiate the laser to the cathode support 6 (ribbon) with a condensing diameter smaller than its width. Therefore, when performing laser welding on a cathode support having a width of 0.3 mm, the condensing diameter of the laser light applied to the cathode support is set to a dimension smaller than the width of the cathode support by 0.3 mm, that is, about 0.25 mm in diameter. , Preferably 0.2 mm or less.

However, as the condensing diameter of the laser beam is reduced, the welding area between the cathode support and the cathode sleeve 1 is reduced, so that the fixing strength (welding strength) between the cathode support and the cathode sleeve is reduced. Occurs. Also, when the condensing diameter of the laser beam is small, the energy density is high, so that the occurrence of splash (melting and scattering), the perforation and breakage of the cathode support are liable to occur, and the problem that the welding quality is deteriorated occurs. . Further, the same problem occurs even when the shape of the cathode support is a wire having a circular cross section.

Further, when the impregnated cathode structure and the oxide type cathode structure are incorporated into a cathode ray tube such as a color picture tube and operated, a problem occurs that a color shift occurs in a displayed image. That is, when the cathode assembly is incorporated in the cathode ray tube, the first grid is provided in front of the cathode substrate in the electron emission direction, and the cathode assembly and the grid constitute the electron gun assembly.
However, if the heater is heated for a long time in the cathode structure to heat the cathode base, the cathode support may be thermally deformed and the cathode sleeve may be displaced. Then, the position of the cathode base attached to the cathode sleeve shifts, and the distance between the cathode base and the first grid fluctuates. As a result, a color shift occurs in the displayed image.

According to the present invention, when the cathode support is fixed to the cathode sleeve by laser welding, stable welding can be performed without reducing the welding strength of the welded portion and without breaking the cathode support. It is an object of the present invention to provide an impregnated type cathode structure or an oxide type cathode structure capable of preventing thermal deformation of a support and obtaining a stable image.

Further, the present invention provides a manufacturing method capable of obtaining an impregnated type cathode structure or an oxide type cathode structure capable of securely and stably fixing a cathode support and a cathode sleeve by laser welding. That is the task. Another object of the present invention is to provide a highly reliable electron gun structure and electron tube.

[0021]

According to the first aspect of the present invention, there is provided an impregnated cathode assembly comprising: a cathode substrate impregnated with an electron emitting substance;
A cathode sleeve having the cathode substrate mounted at one end, a cathode support cylinder disposed outside the cathode sleeve, and a cathode support having one end fixed to the cathode sleeve and the other end fixed to the cathode support cylinder. The cathode support comprises a core material made of a high melting point metal, and a metal material having a melting point lower than the high melting point metal forming the core material, and at least the cathode support body and the cathode sleeve in the core material. And a covering material for covering the fixing portion.

According to this configuration, since the cathode support uses the core material made of a high melting point metal, it is used under severe thermal conditions of being attached to the cathode sleeve heated by the heater. It has high temperature strength enough to withstand high temperatures. In addition, the coating material made of a metal having a lower melting point than the core material provided on the cathode support is irradiated with a laser to melt and fix the cathode support to the cathode sleeve, so that the core material is reliably welded with high welding strength. Can be fixed to the cathode sleeve.

At the time of this laser welding, laser welding can be performed without restricting the laser beam to a smaller converging diameter due to the size of the core material. That is, it is to melt only the coating material made of a metal having a lower melting point than the core material of the cathode support. For this reason, it is not necessary to squeeze the laser extremely, that is, the energy density can be lowered. Can be welded to the core material of the cathode support and the cathode sleeve, which have a high melting point, without affecting the heat.

[0024] Thereby, very good welding can be performed even if the converging diameter of the laser beam is larger than the width or diameter of the cathode support. It is possible to prevent the occurrence of perforations and breaks in the support, and to prevent the perforations in the cathode sleeve, thereby improving the welding quality. Accordingly, high-quality welding can be achieved without deteriorating the strength of the fixed portion (welded portion) between the cathode support and the cathode sleeve, and reliability and manufacturing yield can be greatly improved.

Since the cathode support uses a high-melting-point metal as a core material, thermal deformation can be suppressed even when the cathode base heater is heated by energizing the heater of the cathode assembly for a long time. . Therefore, when the cathode structure is incorporated in a cathode ray tube such as a color picture tube, even if the cathode structure is operated for a long time,
It can be prevented that the distance between the cathode base and the first grid does not fluctuate and color shift of the displayed image occurs.

According to a second aspect of the present invention, in the impregnated cathode structure according to the first aspect, the refractory metal forming the core material of the cathode support is W, Mo, Re, Ta, Nb, Ir, and mainly these. It is characterized by being at least one kind selected from alloys as components. According to the present invention, the core of the cathode support can be formed of an appropriate material.

According to a third aspect of the present invention, in the impregnated cathode assembly according to the first aspect, the metal forming the coating material of the cathode support is Pt, Rh, Pd, V, Au, Ti, and a main component thereof. Or at least one kind selected from alloys. According to the present invention, the coating material of the cathode support can be formed of an appropriate material.

According to a fourth aspect of the present invention, there is provided a method for manufacturing an impregnated type cathode assembly, comprising: a cathode sleeve on which a cathode substrate impregnated with an electron emitting substance is mounted; and a cathode support cylinder having the cathode sleeve disposed outside the cathode sleeve. When fixing the cathode support to be supported, a core material made of a high melting point metal, and a metal material having a melting point lower than that of the high melting point metal forming the core material, at least the cathode support and the cathode sleeve in the core material A step of preparing a cathode support having a coating material for covering the fixing portion with, and irradiating only the coating material of the cathode support by irradiating a laser, and melting the cathode support through the molten coating material. Fixing the cathode sleeve.

According to the present invention, the cathode support and the cathode sleeve are firmly and stably fixed by laser welding.
It is possible to obtain an impregnated-type cathode assembly capable of firmly welding and fixing both with excellent welding quality.

An electron gun structure according to a fifth aspect of the present invention is the first aspect of the invention.
And an impregnated cathode assembly according to any one of claims 3 to 7. According to this configuration, a highly reliable electron gun structure can be obtained.

According to a sixth aspect of the present invention, there is provided an electron tube using the electron gun assembly according to the fifth aspect. According to this configuration, a highly reliable electron tube can be obtained. The oxide-type cathode structure of the invention according to claim 7, a cathode base on which a layer of an electron emitting material made of oxide is formed, and a cathode sleeve on which the cathode base is mounted at one end,
A cathode support cylinder disposed outside the cathode sleeve; and a cathode support having one end fixed to the cathode sleeve and the other end fixed to the cathode support cylinder, wherein the cathode support has a high melting point metal. And a coating material made of a metal material having a melting point lower than that of the high melting point metal forming the core material, the coating material covering at least a fixing portion between the cathode support and the cathode sleeve in the core material. Features.

According to this configuration, since the cathode support uses the core material made of a high melting point metal, it has a high temperature strength enough to withstand use under severe thermal conditions. . In addition, the coating material made of a metal having a lower melting point than the core material provided on the cathode support is irradiated with a laser to melt and fix the cathode support to the cathode sleeve, so that the core material is reliably welded with high welding strength. Can be fixed to the cathode sleeve.

At the time of this laser welding, laser welding can be performed without being restricted by the size of the core material and converging the laser beam to a smaller converging diameter. This enables extremely good welding even if the laser beam focus diameter is larger than the width and diameter of the cathode support, and prevents the occurrence of splashes and punctures and breaks in the cathode support. In addition, the occurrence of perforations in the cathode sleeve can be prevented, and the welding quality can be improved. Accordingly, the welded portion (fixed portion) between the cathode support and the cathode sleeve can achieve high-quality welding without deterioration in strength, and can greatly improve reliability and production yield.

Since the cathode support uses a high-melting-point metal as a core material, thermal deformation can be suppressed even when the cathode base heater is heated by energizing the heater of the cathode assembly for a long time. . Therefore, when the cathode structure is incorporated in a cathode ray tube such as a color picture tube, even if the cathode structure is operated for a long time,
It can be prevented that the distance between the cathode base and the first grid does not fluctuate and color shift of the displayed image occurs.

According to an eighth aspect of the present invention, in the oxide cathode structure according to the seventh aspect, the refractory metal forming the core material of the cathode support is W, Re, Mo, Ta, Nb or the like. It is characterized by being at least one selected from alloys as main components. According to the present invention, the core of the cathode support can be formed of an appropriate material.

According to a ninth aspect of the present invention, in the oxide cathode structure according to the seventh aspect, the metal forming the cathode sleeve includes Ni, an alloy containing Ni as a main component, and Ni,
At least one selected from alloys in which a high melting point metal is dispersed in an alloy containing Cr as a main component, and the metal forming the coating material of the cathode support is made of Ni and an alloy containing Ni as a main component. It is characterized by being at least one selected from the group. According to the present invention, the coating material of the cathode sleeve and the cathode support can be formed of an appropriate material.

A method of manufacturing an oxide-type cathode structure according to a tenth aspect of the present invention is a method for manufacturing a cathode sleeve, comprising: a cathode sleeve on which a layer of an electron-emitting substance made of an oxide is formed; At the time of fixing the cathode support to be supported on the cathode support tube arranged in the core material, a core material made of a high melting point metal, a metal material having a melting point lower than the high melting point metal forming the core material, and at least the core material A step of preparing a cathode support having a coating covering the fixed portion of the cathode support and the cathode sleeve, and irradiating only the coating of the cathode support with a laser to melt the coating,
Fixing the cathode support to the cathode sleeve via a molten coating material.

According to the present invention, the cathode support and the cathode sleeve are firmly and stably fixed by laser welding.
It is possible to obtain an oxide-type cathode assembly that can firmly weld and fix both with excellent welding quality.

According to an eleventh aspect of the present invention, there is provided an electron gun assembly using the oxide cathode assembly according to any one of the seventh to ninth aspects. According to the configuration of the present invention, a highly reliable electron gun structure can be obtained.

An electron tube according to a twelfth aspect of the present invention is the eleventh aspect.
Characterized by using the electron gun assembly described in (1).
According to the configuration of the present invention, a highly reliable electron tube can be obtained.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a partially cutaway front view showing the structure of the impregnated cathode assembly. FIG. 2 is an enlarged view of the cathode support in FIG.
FIG. 2A is a cutaway plan view of the cathode support, and FIG. 2B is a cross-sectional view along AA 'in FIG. 2A. FIG. 3 is a diagram showing a fixing portion of the cathode support of the impregnated cathode assembly according to the first embodiment. FIG. 3A is a cross-sectional view of the cathode support cut in an axial direction, and FIG. () Is a cross-sectional view along the line BB 'in FIG.

In the figure, reference numeral 21 denotes a cathode sleeve 21 which is a cylindrical body having both ends opened. A cup 23 to which a disk-shaped cathode base 22 is attached is fitted and fixed to one end of the cathode sleeve 21.
Is impregnated with an electron emitting material (emitter). The cathode sleeve 21 is formed of, for example, a metal such as Ta, Nb, Mo, Re, or an alloy thereof. Cathode substrate 22
Is made of, for example, a tungsten sintered body having a porosity of about 20%, and is impregnated with an electron-emitting substance made of BaO, Al ₂ O ₃ , and CaO. The cup 23 is made of, for example, Ta, and is for preventing insulation deterioration of the heater 24 caused by evaporation of the emitter from the cathode base 22 scattered toward the heater 24 described later. In addition,
The cup 23 may be formed integrally with the cathode sleeve 21.

A cathode base 22 is provided inside the cathode sleeve 21.
A heater 24 for heating the heater 2 is provided.
4 is attached to the heater tab 43 as shown in FIG. A cathode support cylinder 25 made of a cylindrical body is coaxially arranged outside the cathode sleeve 21. The cathode support cylinder 25 is made of, for example, Kovar (Fe—Ni—Co alloy), and has a larger length and a larger outer diameter than the cathode sleeve 21. One end of the cathode support cylinder 25 is formed with a shoulder 25a that is bent inward at a right angle in the entire circumferential direction, and a hole 2 is formed in a portion surrounded by the shoulder 25a.
5b are formed. The cathode sleeve 21 is inserted into the hole 25 b of the cathode support tube 25, and the end having the cup 23 projects outward from the cathode support tube 25. The cathode support tube 25 is supported by a strap 42 as shown in FIG.

A plurality of cathode supports 26 are arranged inside the cathode support tube 25 at circumferentially spaced positions. The cathode support 26 has a shape extending in the axial direction of the cathode support tube 21, and has one end fixed to the outer peripheral surface of the other end of the cathode sleeve 21 by, for example, laser welding. Is projected outward through a hole 25b of the cathode support tube 25 and fixed to the outer surface of the shoulder 25a by, for example, laser welding.

The cathode support 26 is configured as shown in FIG. That is, the cathode support 26 is made of a core material 261 made of a refractory metal having a high temperature strength and a circular cross section, and a coating made of a metal having a lower melting point than the core material 261 formed so as to cover the core material 261. Material 262. In this embodiment, the covering member 262 covers the entire length of the core member 261.

Then, as shown in FIG. 3, the coating material 262 is melted by laser irradiation and solidified and fixed to the outer peripheral surface of the cathode sleeve 21 so that the core material 261 is attached to one end of the cathode support 26 as shown in FIG. 21.
The other end of the cathode support 26 is similarly fixed to the outer surface of the shoulder 25a of the cathode support tube 25.

Here, the cathode support 26 is manufactured by, for example, a method of manufacturing a clad wire by covering a core material 261 made of a wire material with a coating material 262 formed in a cylindrical shape and then drawing and extending the entire material. A method of manufacturing by forming a coating material 262 on the outer peripheral surface of the core material 261 by plating;
It is manufactured by various methods such as a method of forming and manufacturing a coating material 262 on the outer peripheral surface by vapor deposition.

The metal material used for the core material 261 of the cathode support 26 must have sufficient high-temperature strength in view of the operating temperature of the impregnated cathode assembly, and generally has a high melting point of 2500 ° C. or higher. A melting point metal is required, and a material having a low vapor pressure is required. From the above points, the core material 261
Is suitably formed of at least one selected from W, Μo, Re, Ta, Nb, Ιr and alloys containing these metals as main components.

The material forming the covering material 262 has a low vapor pressure, and in order to fix the material utilizing the difference in melting point, which is a feature of the present invention, the melting point is lower than the melting point of the core material 261. Preferably, a material having a melting point lower than that of the core material by 500 ° C. or more is preferably used. From the above points, the coating material 26
It can be said that 2 is suitably formed of at least one selected from Δt, Rh, Pd, V, Au, Ti or an alloy containing these as a main component.

The ratio of the thickness of the core material 261 to the thickness of the coating material 262 in the cathode support 26 is determined to be an appropriate value by the following test. Table 1 shows that the diameter of the cathode support was 0.05 mm, and the thickness of the coating was changed by using Ta for the cathode sleeve, W for the core material of the cathode support, and Pt for the coating material of the cathode support. It evaluated the weldability at that time. The following was found from Table 1.

The evaluation method is as follows. That is, after welding, the cathode sleeve is inserted into the cored bar, the cathode support is sandwiched between tweezers, and the cathode support is pulled outward and broken so that the welded portion becomes a fulcrum. The welding strength was evaluated from the tensile force and the shape of the fractured part at this time.

[0052]

[Table 1]

In the cathode support 26, when the thickness of the coating material 262 is 0.0025 mm, that is, when the total coverage is 10%, welding is possible but welding strength is low. Further, in the case of the coating material 262 having a thickness of 0.015 mm, that is, a total coverage of 60%, it is necessary to increase the laser energy in laser welding in order to sufficiently melt the coating material 262. Then, it was found that the cathode sleeve 21 was partially affected by the heat and melted.

On the other hand, in the cathode support 26, the thickness of the coating material 262 is 0.005 mm, that is, the total coverage is 20%.
And the thickness of the coating material 262 is 0.01 mm, that is, the total coating ratio is 4
It was found that 0% can be welded well. In addition,
The total coverage of the coating material 262 is represented by a numerical value obtained by reducing both sides of the coating material 262 by the diameter of the cathode support. Therefore, the total coverage of the coating material 262 is preferably 10 to 60%, more preferably 20 to 40%.

Then, the cathode support 26 is connected to the cathode sleeve 2.
The manufacturing process to be attached to No. 1 is performed by the following method. First, the cathode substrate 22 impregnated with the electron emitting material is T
a to the cathode sleeve 21
Into one open end. Then, the cathode sleeve 21 and the side wall of the cup 23 are fixed by a method such as laser welding. After that, a core metal (not shown) is inserted into the inside of the cathode sleeve 21 from the open end of the other end of the cathode sleeve 21.

On the other hand, according to the above-described manufacturing method, a material for the cathode support 26 is manufactured by covering the entire periphery of a core 261 made of a wire having a circular cross section with a coating 262, and this material is fed out by a fixed size by a feeder. Further, the end portion of this material is held by a vacuum chuck, cut into a certain size, and formed into a certain shape to manufacture the cathode support 26.

Thereafter, the cathode support 26 is advanced while being chucked, and pressed against the cathode sleeve 21. In this state, the laser is irradiated on the cathode support 26,
Is melted to fix the cathode support 26 to the cathode sleeve 21. The laser welding conditions are such that only the coating material 262 of the cathode support 26 is melted and the core material 261 and the sleeve 21 are not affected by heat.

In this welding, as shown in FIG. 3, the molten coating material 262 flows to the outer surface of the cathode sleeve 21 and solidifies and fixes.
1 and the coating material 262 melt-solidified.

As described above, since the cathode support 26 uses the core material 261 made of a high melting point metal,
4 has a high-temperature strength enough to withstand use under severe thermal conditions of being attached to the cathode sleeve 21 heated at 4. Further, a coating material 262 made of a metal having a lower melting point than the core material 261 provided on the cathode support 26 is irradiated with a laser beam to be melted, and the cathode support 26 is fixed to the cathode sleeve 21 so that the core material 261 is fixed. Can be securely fixed to the cathode sleeve 21 with high welding strength.

At the time of this laser welding, laser welding can be performed without being restricted by the size of the core material 261 and converging the laser beam to a smaller converging diameter.
That is, only the coating material 262 made of a metal having a low melting point of the cathode sleeve 21 and the cathode support 26 is melted. For this reason, it is not necessary to stop the laser light extremely, that is, the energy density can be lowered. The core material 261 and the cathode sleeve 21 having a higher melting point than the coating material 262 can be welded without affecting the heat. Thereby, even if the converging diameter of the laser beam is larger than the width and diameter of the cathode support 26, very good welding can be performed.

Accordingly, the cathode support 26 and the cathode sleeve 2
In addition, it is possible to prevent the occurrence of a splash caused by an excessively high energy density of laser light in the welded portion where the laser beam 1 is fixed by laser welding, the occurrence of perforation or breakage in the cathode support 26, and the perforation in the cathode sleeve 21. Can be prevented and the quality of welding can be improved. Therefore, high-quality welding can be achieved without deteriorating the strength of the welded portion between the cathode support 26 and the cathode sleeve 21, and the reliability and the production yield can be greatly improved.

Further, according to the above-described method of manufacturing the impregnated cathode structure, the cathode support 26 and the cathode sleeve 21 are firmly and stably fixed by laser welding, and the two are strongly and excellently welded. An impregnated cathode assembly that can be fixed by welding can be obtained. Accordingly, it is possible to manufacture a low-power impregnated cathode assembly of high quality and high reliability at low cost.

The invention of the present application is not limited to the above-described embodiment, but can be implemented with various modifications. For example, in the present embodiment, the covering material 262 is formed over the entire length of the core material 261 of the cathode support 26, but is not limited to this, and is at least as shown in the cutaway plan view of the cathode support in FIG. The covering member 262 may be formed only on the portion of the core member 261 that is fixed to the cathode sleeve 21.

In this embodiment, the cathode support 26
Although the case where the core material 261 is formed of a wire having a circular cross section has been described, the same effect can be obtained with a ribbon-shaped material obtained by rolling the wire. FIG. 5 is a cross-sectional view cut in a direction perpendicular to the longitudinal direction of the cathode support 26 in which a coating material 262 is formed on a ribbon-shaped core material 261 having a rectangular cross section, for example.

The cathode assembly of this embodiment is used by being incorporated into an electron gun assembly, and the electron gun assembly further includes an electron tube,
For example, it is used for a color picture tube. FIG. 12 shows a main part of the electron gun structure 47. In FIG. 12, the same parts as those in FIG. 1 are denoted by the same reference numerals. The cathode support tube 25 of the cathode assembly is connected to the strap 4 via the support cylinder 41.
2 attached. The heater 24 is attached to a strap 44 via a heater tab 43. A first grid 45 is arranged facing the cathode base 32. An electron gun assembly 47 is configured by adding these components to the cathode assembly. The vacuum envelope 46 surrounds the electron gun assembly, and has straps 42 and 44 and a first grid 45 attached thereto.

When the electron tube is a color picture tube, for example, a vacuum envelope having a face portion and a phosphor layer provided on the inner surface of the face portion. It has an electron gun structure arranged opposite to the face portion of the vacuum envelope, and a shadow mask arranged between the phosphor layer and the electron gun assembly.

FIG. 13 shows a specific example of the color picture tube. The envelope has a panel 51, a funnel 52 and a neck 53. Red, blue,
A phosphor layer 54 that emits green light is provided in a stripe state, and the neck 53 has electrons that are arranged in a line along the horizontal axis of the panel 51 and emit electron beams R corresponding to red, blue, and green. A gun structure 47 is provided. Phosphor layer 54
A shadow mask 55 having a large number of fine holes is provided at a position close to and close to. The deflecting device 56 deflects and scans the electron beam R.

In this embodiment, since the cathode support 26 of the cathode structure uses a high-melting metal for the core 261, there is almost no thermal deformation even if the cathode structure is operated for a long time. For this reason, when the cathode base is incorporated in the color picture tube, the distance between the cathode base and the grid provided on the color picture tube does not change, and the occurrence of color shift can be prevented.

Next, embodiments of the present invention will be described in detail. Embodiment 1 In the first embodiment, Ta is used for the cathode sleeve 21, Mo is used for the core material 261 of the cathode support 26, and the coating material 2 is used.
This is the case where Δt is used for 62. The cathode sleeve 21 is obtained by cutting a long Ta sleeve, which is obtained by wire drawing, to a predetermined size, and has an outer diameter of 1.3 m.
m, plate thickness 0.02 mm, length 4 mm. Cathode support 26
Is a thin wire made of a so-called clad wire obtained by drawing a Mo wire with a Δt pipe and then drawing. The dimensions of the cathode support 26 are 0.06 mm in diameter, the diameter of the core 261 is 0.042 mm, and the thickness of one side of the coating 262 is 0.009 mm.

When manufacturing the cathode structure, the cathode base 2
The core metal is inserted into the cathode sleeve 21 to which 2 is attached. The cathode support 26 is formed by cutting the clad wire into a predetermined size and shaping the clad wire into a predetermined shape, and then chucking to form the cathode sleeve 21.
Press against Thereafter, a laser beam of 200 mJ / L is focused on the cathode support 26 with a processing lens to a condensing diameter of 0.3 mm by using a YAG pulse laser machine, and the coating 262 (Ρt layer) on the cathode support 26 is irradiated. Only melts. The melted coating 262 (Δt) flows on the surface of the cathode sleeve 21 made of Ta and solidifies to fix the cathode sleeve 21 and the cathode support 26 together.

This is because the melting point of 1.769 ° C. at which the coating material 262 of the cathode support 26 is formed is changed to the cathode sleeve 21.
The melting point of Ta is 2,996 ° C., which is 850 ° C. or more lower than the melting point of Mo, 2,620 ° C., which forms the core material 261 of the cathode support 26, and only Δt melts at the energy density under the above-described processing conditions. It is by doing.

According to the above embodiment, the cathode support 26 could be securely fixed to the cathode sleeve 21 with high welding strength. Embodiment 2 In the second embodiment, the cathode sleeve 21 is
1.5mm diameter, 0.3mm thickness obtained by press molding,
A Mo sleeve having a length of 3 mm and a melting point of 2,620 ° C. is used.
The cathode support 26 has a diameter of 0.0
A 3 mm melting point of 2,620 ° C. is used for the core material 261, and the coating material 262 is applied to the core material 261 as a melting point of 1,063 ° C.
Is formed by plating to a thickness of 0.005 mm. Then, after positioning the cathode support 26 with respect to the cathode sleeve 21 in the same manner as in the first embodiment, the same laser welding is performed, and the cathode support 2 is formed at 120 mJ in the same manner as in the first embodiment.
6 was fixed to the cathode sleeve 21.

According to the above embodiment, the cathode support 26 was securely fixed to the cathode sleeve 21 with high welding strength. Embodiment 3: In the third embodiment, as the cathode sleeve 21,
After drawing, it was cut to a fixed size to obtain a diameter of 1.6.
An Nb sleeve having a thickness of 0.23 mm and a length of 4 mm is used. This Nb sleeve has a melting point of 2,497 ° C. The core material 261 of the cathode support 26 is made of a W wire having a melting point of 3,410 ° C. and having a diameter of 0.016 mm obtained by wire drawing, and covers about 1 mm of the core material 261 to be fixed to the cathode sleeve 21. As the material 262, Rh having a melting point of 1,966 ° C. is formed by vapor deposition with a thickness of 0.002 mm in a vacuum apparatus. Then, the cathode support 26 and the cathode sleeve 21
Are positioned in the same manner as in the first embodiment, and the same laser welding is performed to fix the same as in the first embodiment.

In each of the above-described examples, the cathode support 2
Although the method of welding the cathode sleeve 6 and the cathode sleeve 21 using a pulsed laser has been described, a similar effect can be obtained with a continuous wave laser if the weld is maintained in an inert gas atmosphere such as Ar gas.

According to the above embodiment, the cathode support 26 was securely fixed to the cathode sleeve 21 with high welding strength. The impregnated cathode assembly using the fixed form of the cathode base 26 and the cathode sleeve 21 shown in the above Examples 1 to 3 was
When a conventionally used electron gun assembly and further the above-mentioned electron gun assembly were used for a conventionally used color picture tube, a highly reliable electron gun assembly and electron tube could be obtained.

A second embodiment according to the present invention will be described with reference to FIGS. FIG. 6 is a partially cutaway front view showing the structure of the oxide cathode structure. FIG. 7 is an enlarged view of the cathode support in FIG.
FIG. 7A is a cutaway plan view of the cathode support, and FIG.
It is sectional drawing which follows the CC 'line of (a). FIG. 8 is a view showing a fixing portion of the cathode support of the oxide cathode structure.
8A is a cross-sectional view of the cathode support taken in the axial direction, and FIG. 8B is a cross-sectional view taken along line DD of FIG. 8A.

A disk-shaped cathode base 32 is fitted and fixed to one end of a cathode sleeve 31 formed of a cylindrical body having both ends opened. The cathode sleeve 31 is, for example, N
It is formed of an i-Cr alloy. The cathode substrate 32 is formed of, for example, W, and has Ba, Sr, C
A layer of the electron-emitting substance 33 made of the oxide a is formed.

A cathode base 32 is provided inside the cathode sleeve 31.
Is disposed. A cathode support cylinder 35 made of a cylindrical body is coaxially arranged outside the cathode sleeve 31. The cathode support cylinder 35 is made of, for example, Kovar (Fe—Ni—Co alloy), and has a longer length and a larger outer diameter than the cathode sleeve 31.
At one end of the cathode support cylinder 35, a shoulder 35a that is bent inward at a right angle is formed over the entire circumferential direction, and a hole 35b is formed at a portion surrounded by the shoulder 35a. The cathode sleeve 31 is inserted into the hole 35 b of the cathode support cylinder 35, and the end having the cup 33 protrudes outside the cathode support cylinder 35.

A plurality of cathode supports 36 are arranged inside the cathode support cylinder 35 at circumferentially spaced positions. The cathode support 36 has a shape extending in the axial direction of the cathode support tube 31. One end of the cathode support 36 is fixed to the outer peripheral surface of the other end of the cathode sleeve 31 by, for example, laser welding, and the other end is fixed. The cathode support tube 35 is exposed to the outside via a hole 35b, and is fixed to the outer surface of the shoulder 35a by, for example, laser welding.

The cathode support 36 is configured as shown in FIG. That is, the cathode support 36 is made of a core material 361 made of a high melting point metal having a high temperature strength and having a circular cross section, and a coating material formed so as to cover the core material and made of a metal having a lower melting point than the core material 361. 362. Then, as shown in FIG. 7, the coating material 362 is melted by laser irradiation and solidified and fixed to the outer peripheral surface of the cathode sleeve 31 so that the core material 361 is fixed to the cathode sleeve 31 at one end of the cathode support 36. Have been. Similarly, the other end of the cathode support 36 has a shoulder 35 of the cathode support cylinder 35.
a is fixed to the outer surface.

Here, the cathode support 36 is manufactured by, for example, a method of manufacturing a clad wire by covering a core material 361 made of, for example, a wire material with a coating material 362 formed in a cylindrical shape and then drawing and extending the whole. A method of manufacturing by forming a coating material 362 on the outer peripheral surface of the core material 361 by plating;
It is manufactured by various methods, such as a method of manufacturing by forming a coating material 362 on the outer peripheral surface by vapor deposition.

The metal material used for the core material 361 of the cathode support 36 must have sufficient high-temperature strength in view of the operating temperature of the oxide-type cathode assembly, and generally has a melting point of 3500 ° C. or higher. A high melting point metal is required, and a material having a low vapor pressure is required. From the above points, core material 3
61 is suitably formed of at least one selected from W, Μo, Re, Ta, Nb, Ιr and alloys containing these metals as main components.

As a metal material for forming the cathode sleeve 31, a Ni—Cr alloy may be used.
An alloy in which a high melting point metal such as W is dispersed in a Ni—Cr alloy, such as a W alloy, may be used.

The materials used for the core material 361 and the coating material 362 in the cathode support 36 need to have sufficient high-temperature strength, and generally require a high melting point metal having a melting point of 2000 ° C. or more, and Materials with low vapor pressure are required.
In addition to having a low vapor pressure, the coating material 362 has at least a core material 36 as described in the above-described embodiment when it is intended to fix using a difference in melting point which is a feature of the present invention.
It is necessary that the melting point is lower than 500 ° C. or more than 1. As described above, as the material of the cathode support 36, W, Re, Mo, Ta, Nb, and alloys containing these as main components are suitable for the core material 361. As the coating material 362, the cathode sleeve 31 to which the cathode support 36 is fixed is made of Ni-Cr.
Since it is composed of an alloy, Ni and an alloy mainly containing Ni are suitable.

Next, in order to define an appropriate thickness ratio of the coating material 362 of the cathode support 36, the core material 3
By using Mo for 61 and Ni for the coating material 362 of the cathode support 36, the cathode support 36 having a diameter of the cathode support 36 of 0.05 mm and a thickness ratio of the coating material 362 changed was manufactured. The weldability with the cathode sleeve 31 made of a -Cr alloy was evaluated.

[0086]

[Table 2]

Table 2 shows the results of examining the weldability with the cathode sleeve 31 depending on the change in the thickness ratio of the coating material 362.
The thickness of the coating material 362 is 0.002 mm, that is, the coating material 3
When the thickness ratio of 62 was as small as 8%, welding was possible but the welding strength was low. Conversely, one side thickness 0.0175
mm, that is, when the thickness ratio of the coating material 362 increases to 70%, the laser energy required to sufficiently melt the coating material 362 must be increased, and the cathode sleeve 31 melts under the influence of heat. 361
Mo has become embrittled.

Good results were obtained when the thickness of the coating material 362 was in the range of 0.0025 mm to 0.015 mm, that is, the thickness ratio of the coating material 362 was 10% to 60%.
In particular, the thickness of the coating material 362 is 0.005 mm to 0.1 mm.
01 mm, that is, the thickness ratio of the coating material 362 is 20
% To 40% were best.

Then, the cathode support 36 is connected to the cathode sleeve 3.
The manufacturing process to be attached to No. 1 is performed by the following method. First, the cathode base 32 on which the electron emitting material is oxidized is fixed to a cup 33 made of Ta or the like, and the cathode sleeve 3
1 into one open end. Then, the cathode sleeve 31
And the side wall of the cup 33 are fixed by a method such as laser welding. Thereafter, a core metal (not shown) is inserted into the inside of the cathode sleeve 31 from the open end of the other end of the cathode sleeve 31.

On the other hand, according to the above-described manufacturing method, a material for the cathode support 36 in which the coating material 362 is entirely covered around the core 361 made of a wire having a circular cross section is manufactured, and this material is fed out by a fixed size by a feeder. Further, the end portion of this material is held by a vacuum chuck, cut into a predetermined size, and formed into a predetermined shape to manufacture the cathode support 36.

Thereafter, the cathode support 36 is advanced while being chucked, and pressed against the cathode sleeve 31. In this state, the laser is applied to the cathode support 36, and the cathode support 36
Is melted to fix the cathode support 36 to the cathode sleeve 31. The laser welding conditions are set so that only the coating material 362 of the cathode support 36 is melted and the core material 361 and the sleeve 31 are not affected by heat.

In this welding, as shown in FIG. 8, the molten coating material 362 flows on the outer surface of the cathode sleeve 31 to solidify and fix, so that the cathode support 36 is
1 and the coating material 362 that has been melt-solidified can be completely fixed.

As described above, since the cathode support 36 uses the core material 361 made of a high melting point metal,
4 has a high temperature strength enough to withstand use under the severe thermal conditions of being attached to the cathode sleeve 31 heated at 4. Further, a coating material 362 made of a metal having a lower melting point than the core material 361 provided on the cathode support 36 is irradiated with a laser beam to be melted, and the cathode support 36 is fixed to the cathode sleeve 31 so that the core material 361 is fixed. Can be securely fixed to the cathode sleeve 31 with high welding strength.

At the time of this laser welding, laser welding can be performed without being restricted by the size of the core material 361 and converging the laser beam to a smaller converging diameter.
That is, only the coating material 362 made of a metal having a low melting point of the cathode sleeve 31 and the cathode support 36 is melted. Therefore, it is not necessary to stop the laser light extremely, that is, the energy density can be reduced. The core material 361 and the cathode sleeve 31 having a higher melting point than the coating material 362 can be welded without affecting the heat. Thereby, very good welding can be performed even if the converging diameter of the laser beam is larger than the width and diameter of the cathode support 36.

Therefore, the cathode support 36 and the cathode sleeve 3
In addition, it is possible to prevent the occurrence of a splash caused by an excessively high energy density of laser light in the welded portion where the laser beam No. 1 is fixed by laser welding, the occurrence of perforation or breakage in the cathode support 36, and the perforation in the cathode sleeve 31. Can be prevented and the quality of welding can be improved. Therefore, high-quality welding can be achieved without deteriorating the strength of the welded portion between the cathode support 36 and the cathode sleeve 31, and the reliability and the production yield can be greatly improved.

Further, according to the above-described method for manufacturing an oxide type cathode structure, the cathode support 36 and the cathode sleeve 31 are firmly and stably fixed by laser welding, and the two are strongly welded with excellent welding quality. Thus, an oxide-type cathode assembly that can be fixed by welding can be obtained. Therefore, a high-quality and highly reliable low-power-consumption oxide-type cathode assembly can be manufactured at low cost.

The present invention is not limited to the above-described embodiment, but can be implemented in various modifications. For example, in the present embodiment, the covering member 362 is formed over the entire length of the core member 361 of the cathode support member 36. However, the present invention is not limited to this, and as shown in the cutaway plan view of the cathode support member in FIG. The covering member 362 may be formed only on a portion of the core member 361 to be attached to the cathode sleeve 31.

In the present embodiment, the cathode support 36
Although the core material 361 described above is formed of a wire having a circular cross section, the same effect can be obtained with a ribbon-shaped material obtained by rolling the wire. FIG. 10 is a cross-sectional view cut in a direction perpendicular to the length direction of the cathode support 36 in which a coating material 362 is formed on a ribbon-shaped core material 361 having a rectangular cross section, for example.

The cathode structure of this embodiment is used by being incorporated into an electron gun structure. That is, in the first embodiment, the cathode support cylinder 35 is attached to the strap 42 via the support cylinder 41 in the same manner as shown in FIG. The heater 24 is connected to the strap 4 via the heater tab 43.
4 attached. A first grid 45 is arranged facing the cathode base 32. An electron gun structure is configured by adding these parts to the cathode structure. The vacuum envelope 46 surrounds the electron gun assembly, and has straps 42 and 44 and a first grid 45 attached thereto. Further, the electron gun assembly is used for an electron tube, for example, a color picture tube.

Since the cathode support 36 uses a high melting point metal for the core material 361, there is almost no thermal deformation even when the cathode assembly is operated for a long time. For this reason, when the cathode structure is incorporated in the color picture tube, the distance between the cathode base and the grid provided on the color picture tube does not change, and the occurrence of color shift can be prevented.

Embodiment 4 In the fourth embodiment, Mo is used for the core material 31 of the cathode support 30, and
The case where Ni is used for the coating material 32 is shown. Cathode support 30
Is a 0.042 mm diameter Mo wire with a 0.009 mm thickness
Is a thin line having a diameter of 0.06 mm formed by plating Ni. After cutting the cathode support 36 into predetermined dimensions,
It is fixed to the cathode sleeve 31 by laser welding. At that time, a laser of 200 mJ / pulse was focused on a processing lens to a spot diameter of 0.3 mm and irradiated using a YAG pulse laser processing machine. As a result, only the Ni layer melted and flowed and solidified on the surface of the cathode sleeve 2, so that the cathode sleeve 31 and the cathode support 30 were fixed via the Ni coating layer.

The subsequent steps were assembled into a cathode assembly in the same manner as in the prior art. The cathode assembly manufactured in this example was assembled in a color picture tube, and the change in cutoff voltage was examined.
When the color picture tube is used for a long time, the cathode support 36 is thermally deformed, and the dimensions of the first grid and the surface of the cathode base 32 change. This dimensional change is usually not constant for each of the red, green, and blue electron guns, so that the electron beam current incident on the phosphor screen changes and color shift occurs. Also,
Brightness degradation also occurs. Therefore, the amount of thermal deformation of the cathode was confirmed by a cathode heating / cooling test of the color picture tube.

The test conditions were such that the temperature reached by the cathode was 9
Set the applied voltage to 50 ° C b, turn on for 5 minutes,
The test was repeated 4000 times per minute. FIG. 11 shows a diagram of the change of the cutoff voltage. As is apparent from FIG. 11, the change in the cutoff voltage of the cathode structure of the present invention is small. That is, this indicates that thermal deformation at high temperature is small. That is, in the cathode structure of the present invention, since the core material 361 of the cathode support 36 is made of a high-melting-point metal having high high-temperature strength, thermal deformation is reduced, and as a result, a change in cutoff voltage is prevented. be able to.

Embodiment 5 In the fifth embodiment, Ta having a diameter of 0.04 mm obtained by wire drawing and cutting to a predetermined size is used as a core material 361, and Ni is coated on its surface as a coating material 362. It was molded with a thickness of 0.01 mm. After that, when laser irradiation was performed using the same laser processing system as in Example 4 under the same conditions, fixing was performed in the same manner as in Example 4. Further, the cathode assembly manufactured in this example was assembled into a color picture tube, and the same test as in Example 1 was performed. The same result was obtained.

[0105]

As described above, according to the impregnated type cathode structure or the oxide type cathode structure of the present invention, the cathode support is fixed to the heated cathode sleeve because the core material is a high melting point metal heater. Has a high temperature strength enough to be used under severe thermal conditions, and irradiates the coating material with laser light to melt it and fix the core material to the cathode sleeve. The material can be securely fixed to the cathode sleeve with high welding strength.

When the cathode support is fixed to the cathode sleeve by laser welding, the laser beam is applied to the core by melting only the coating made of a metal having a lower melting point than the core of the cathode support. Laser welding can be performed while being restricted by size and avoiding narrowing down to a small focusing diameter,
Therefore, the core material and the cathode sleeve, which have a lower energy density and a higher melting point than the coating material, can be welded without affecting the heat.

As a result, very good welding can be performed even if the laser condensing diameter is larger than the width and diameter of the cathode support, splashes caused by an excessively high energy density of the laser, and perforations in the cathode support. In addition to preventing the occurrence of cutting and fusing, it is possible to prevent the occurrence of perforations in the cathode sleeve and improve the welding quality. Therefore, high quality welding can be achieved without deteriorating the strength of the welded portion between the cathode support and the cathode sleeve, and as a result, the reliability and the production yield can be greatly improved. As a result, a high-quality and highly reliable low-power-consumption type cathode assembly can be provided at a low price.

Further, according to the electron gun structure of the present invention, a highly reliable electron gun structure can be obtained. According to the electron tube of the present invention, a highly reliable electron tube can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a structure of an impregnated cathode assembly according to a first embodiment of the present invention.

FIG. 2 is an enlarged view showing a cathode support used for the impregnated cathode assembly of the embodiment.

FIG. 3 is a diagram showing a fixing portion of a cathode support used in the impregnated cathode assembly of the embodiment.

FIG. 4 is a diagram showing a different form of the cathode support.

FIG. 5 is a view showing a different form of the cathode support.

FIG. 6 is a partially cutaway front view showing a structure of an oxide cathode structure according to a second embodiment of the present invention.

FIG. 7 is an enlarged view showing a cathode support used in the oxide cathode structure of the embodiment.

FIG. 8 is a diagram showing a fixing portion of a cathode support used in the oxide-type cathode structure of the embodiment.

FIG. 9 is a diagram showing a different form of the cathode support.

FIG. 10 is a diagram showing a different form of the cathode support.

FIG. 11 is a diagram showing the amount of deformation of a cathode base by a cathode heating / cooling test of a color picture tube.

FIG. 12 is a view showing an electron gun assembly.

FIG. 13 is a view showing a picture tube.

FIG. 14 is a partially cutaway front view showing a conventional impregnated cathode structure.

FIG. 15 is a partially cutaway front view showing a conventional oxide type cathode structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 ... Cathode sleeve, 22 ... Cathode base 23 ... Cup, 24 ... Heater, 25 ... Cathode support cylinder, 26 ... Cathode support, 261 ... Core material, 262 ... Coating material, 31 ... Cathode sleeve, 32 ... Cathode base 33 ... Cup, 34: heater, 35: cathode support cylinder, 36: cathode support, 361: core material, 362: coating material.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location H01J 29/04 H01J 29/04 (72) Inventor Akihito Hara 7 Nisshincho, Kawasaki-ku, Kawasaki-shi, Kawasaki, Kanagawa Prefecture No. 1 Toshiba Electronic Engineering Co., Ltd. (72) Inventor Toru Yabe 50 Hyogo-ku, Himeji-shi, Hyogo Pref.

Claims (12)

[Claims] 1. A cathode substrate impregnated with an electron emitting material,
A cathode sleeve having the cathode substrate mounted at one end, a cathode support cylinder disposed outside the cathode sleeve, and a cathode support having one end fixed to the cathode sleeve and the other end fixed to the cathode support cylinder. The cathode support comprises a core material made of a high melting point metal, and a metal material having a melting point lower than the high melting point metal forming the core material, and at least the cathode support body and the cathode sleeve in the core material. And a covering material for covering the fixed portion of the impregnated cathode structure. 2. The refractory metal forming the core of the cathode support is at least one selected from the group consisting of W, Mo, Re, Ta, Nb, Ir and alloys containing these as a main component. The impregnated cathode structure according to claim 1, wherein: 3. The metal forming the coating material of the cathode support is at least one selected from Pt, Rh, Pd, V, Au, Ti or an alloy containing these as a main component. The impregnated cathode assembly according to claim 1. 4. A method for fixing a cathode sleeve on which a cathode substrate impregnated with an electron-emitting substance is mounted and a cathode support for supporting the cathode sleeve on a cathode support tube disposed outside the cathode sleeve, has a high melting point. A core material made of metal, and a coating material made of a metal material having a lower melting point than the high melting point metal forming the core material, and covering at least a fixing portion of the core material between the cathode support and the cathode sleeve. A step of preparing a cathode support, and a step of irradiating only the coating material of the cathode support with a laser to melt and fixing the cathode support to the cathode sleeve via the melted coating material. A method for producing an impregnated cathode structure. 5. An electron gun assembly comprising the impregnated cathode assembly according to any one of claims 1 to 3. 6. An electron tube using the electron gun assembly according to claim 5. 7. A cathode base on which a layer of an electron-emitting substance made of an oxide is formed, a cathode sleeve on which the cathode base is mounted at one end, a cathode support cylinder disposed outside the cathode sleeve, and one end. A cathode support fixed to the cathode sleeve and the other end fixed to the cathode support tube, the cathode support comprising a core material made of a high melting point metal, and a high melting point metal forming the core material. An oxide-type cathode structure, comprising: a metal material having a lower melting point; and a covering material for covering at least a fixing portion of the core material between the cathode support and the cathode sleeve. 8. The refractory metal forming the core of the cathode support is at least one selected from the group consisting of W, Re, Mo, Ta, Nb and alloys containing these as main components. The oxide-type cathode structure according to claim 7, wherein 9. The metal forming the cathode sleeve is N.
at least one selected from an alloy containing i and Ni as main components and an alloy containing Ni and Cr as main components and a refractory metal dispersed therein, and a metal forming the coating material of the cathode support; 8. The oxide cathode assembly according to claim 7, wherein is at least one selected from Ni and an alloy containing Ni as a main component. 10. A cathode sleeve on which a cathode substrate on which a layer of an electron-emitting substance made of an oxide is formed is mounted, and a cathode support for supporting the cathode sleeve on a cathode support cylinder disposed outside the cathode sleeve. At the time of fixing, a core material made of a high melting point metal and a metal material having a melting point lower than that of the high melting point metal forming the core material, and covering at least a fixing portion of the core material between the cathode support and the cathode sleeve. Preparing a cathode support having a coating material to be applied, and irradiating only the coating material of the cathode support by irradiating a laser, and fixing the cathode support to the cathode sleeve via the melted coating material. A method for producing an oxide-type cathode structure, comprising the steps of: 11. An electron gun structure comprising the oxide cathode structure according to claim 7. Description: 12. An electron tube using the electron gun assembly according to claim 11.