JP2000260314A - Manufacture of impregnated negative electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacture method of an impregnated negative electrode capable of suppressing particles or the like generated from unnecessary electrons and an excessive electron radiating material from emitting, providing a stable electron emitting characteristic, prolonging a life, and having excellent productivity. SOLUTION: A porous body 11 of an integrated structure containing tungsten powder and having a front surface containing an electron emitting region 11a is prepared. Then an elastic member 12 is interposed between a back surface of the porous body 11 and a polishing tool 13. The front surface of the porous body 11 is made contact with a polishing surface plate spread with abrasive grains and a part corresponding to a peripheral region of the front surface is polished. Pores of the porous body are crashed and a non-porous surface 11b is formed on the front surface of the porous body 11. An electron radiating substance 1a is impregnated in the porous body 11 to complete this impregnated negative electrode 1. This impregnated negative electrode suppresses emission of unnecessary electrons and evaporation of redundant particles of the electron radiating material 1a in operating a negative electrode and provides a stable electron emitting characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the barium carbonate in the porous body which is formed by a refractory metal (BaCO ₃₎
The present invention relates to a method for producing an impregnated cathode impregnated with an electron-emitting substance (emitter).

[0002]

2. Description of the Related Art An impregnated cathode is used for an electron gun of a cathode ray tube such as a picture tube and a display tube, and an electron tube such as an image pickup tube and a high-frequency oscillation tube, and electrons (thermoelectrons) are emitted from the impregnated cathode. It has become so.

Factors that determine the quality of the impregnated cathode include, for example, cathode cutoff voltage characteristics and electron emission (grid emission) characteristics.
It is important to suppress the fluctuation of the cathode cutoff voltage. This cathode cutoff voltage is
It depends on the distance between the cathode and the first grid, the distance between the first grid and the second grid, the thickness of the first grid and the second grid, the hole diameter of the first grid and the second grid, and the like. Grid emission is a symptom in which unintended electron emission (emission) is made from excess barium or the like attached to a grid (G1, G2, etc.),
It is important to suppress this. In order to suppress unnecessary emission of electrons without deteriorating the cathode cut-off voltage characteristics, a portion corresponding to the electron emission region in the porous sintered body constituting the impregnated cathode has holes. It is necessary to reduce the porosity in portions corresponding to other regions and to reduce the porosity, or to eliminate vacancies to control excess evaporation of the impregnated electron-emitting substance from regions other than the electron-emitting region.

A conventional impregnated cathode has an integral structure consisting of only a porous sintered body made of a high-melting point metal such as tungsten (W), and a porous fired part corresponding to an electron emission region. It has a two-body structure in which a portion corresponding to the peripheral region is formed of a non-porous metal having excellent heat resistance, and these are fixed by welding or the like (for example, Japanese Patent Application Laid-Open No. 60-62034). Publication).

[0005]

However, such conventional impregnated cathodes have the following problems. In other words, it is difficult to intentionally locally change the porosity of the monolithic structure having only the porous sintered body, and the impregnated cathode in which the impregnation amount of the electron emitting material is arbitrarily controlled is used. It was extremely difficult to obtain. When a sufficient amount of electron emitting material is impregnated to obtain stable electron emission characteristics, barium (Ba) or barium oxide (Ba) as an electron emitting material is used during cathode operation.
O) may evaporate and adhere to the first grid or the second grid. Therefore, grid emission occurs. Further, there has been a problem that the distance between the impregnated cathode and the first grid and the distance between the first grid and the second grid change, and the cathode cutoff voltage fluctuates (drifts).

On the other hand, a two-body structure composed of a porous sintered body and a non-porous metal having excellent heat resistance cannot impregnate an electron emitting substance into the metal having excellent heat resistance. In addition, this part could not serve as a storage for the electron-emitting substance. Therefore, it is not possible to secure a sufficient amount of electron emitting material to obtain stable electron emission characteristics in the cathode, and the electron emission characteristics are reduced,
There was a problem that the life of the cathode was shortened. There is also a problem that the manufacturing process is complicated and the cost is high.

The present invention has been made in view of such a problem, and an object of the present invention is to suppress emission of unnecessary electrons and particles generated from an excessive electron emitting material, thereby obtaining a stable electron emission characteristic. Another object of the present invention is to provide a method for producing an impregnated cathode capable of extending the life.

[0008]

In order to achieve the above object, a method of manufacturing an impregnated cathode according to the present invention employs the following constitution. That is, the method for producing an impregnated cathode of the present invention is a method for producing an impregnated cathode in which an electron-emitting substance is impregnated into a conductive porous body having an electron emission region and other peripheral regions on the front surface. Then, after preparing a porous body having a portion corresponding to the electron emission region on the front surface and a portion corresponding to other peripheral regions, an elastic member is provided between the back surface of the porous body and the polishing jig. The surface of the peripheral region of the porous body is made non-contact by interposing the front surface of the porous body against the polishing platen on which the abrasive particles are scattered, and polishing a portion corresponding to the peripheral region of the front surface. This includes a step of forming a porous surface.

In the method for producing an impregnated cathode according to the present invention,
By polishing, the surface of the peripheral region of the porous body undergoes plastic deformation and is sealed, and becomes a non-porous surface for suppressing emission of an electron-emitting substance or the like.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the porous body has a step in which a portion corresponding to the electron emission region on the front surface is a bottom surface. It has a part.

According to a third aspect of the present invention, there is provided a method for manufacturing an impregnated cathode, wherein
A step between the electron emission region on the front surface of the porous body and other peripheral regions is 10 μm or less.

According to a fourth aspect of the present invention, in addition to the first, second, or third aspect, the elastic member is made of an organic polymer having tackiness on at least one surface. It is a sheet.

According to a fifth aspect of the present invention, there is provided a method for manufacturing an impregnated cathode, according to the first, second, third, or fourth aspect.
In addition to the above configuration, the polishing jig is a plate made of metal or ceramics having a parallel plane.

According to a sixth aspect of the present invention, in addition to the first, second, third, fourth, or fifth aspect of the present invention, in addition to the configuration of the impregnated cathode, the polishing platen has a parallel plane. Characterized in that it is a plate made of metal or ceramic.

According to a seventh aspect of the present invention, there is provided a method for manufacturing an impregnated cathode, in addition to the first aspect, the second aspect, the third aspect, the fourth aspect, the fifth aspect, and the abrasive grain. Is a metal oxide, carbide, nitride, or diamond, and has a particle size of 0.1 μm or more.

According to a method of manufacturing an impregnated cathode according to claim 8, in addition to the structure according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, or claim 7, hand,
The conductive porous body is a sintered body having an integral structure containing at least one of tungsten and molybdenum metal powder.

[Operation] In the method of manufacturing an impregnated cathode according to the present invention, a region corresponding to the peripheral region of the electron emission region on the front surface has a step higher than that corresponding to the electron emission region inside the peripheral region. Such a porous body is prepared, and a portion corresponding to a peripheral region of the front surface is polished to be a non-porous surface. At this time, the step between the electron emission region and the peripheral region is 1
It must be below 0 μm, preferably below 5 μm. This is because if the step exceeds 10 μm, the electron emission characteristics become unstable, and it becomes difficult to accurately check the distance between the impregnated cathode and the first grid.

The porous body is usually produced by press-molding granules and then sintering to form a columnar shape having a concave step on the surface having a portion corresponding to the electron emission region as a bottom surface. At this time, the step between the portion corresponding to the electron emission region of the porous body and the portion corresponding to the peripheral region is, for example, when molding and sintering are performed using a mold having a step of 0.05 mm. The variation is as small as about ± 0.002 mm. On the other hand, the thickness of the entire columnar porous body is much larger than the size of the step, so that the thickness varies greatly due to fluctuations in press pressure during molding and fluctuations in shrinkage due to sintering. . For example, the thickness is 0.65m
m, the variation is ± 0.0
It is about 3 mm. Therefore, if a large number of porous bodies are polished at the same time, it becomes difficult to adjust the amount of polishing, and a problem arises in that the height of the steps on the surface of the porous bodies varies. That is, when a large number of porous bodies are placed on the same polishing jig made of a flat plate, and the front surface of the porous bodies is simultaneously applied to a polishing platen in which abrasive grains are dispersed, the thickness of each porous body is increased. Therefore, a large number of porous body front surfaces cannot be applied to the surface plate at the same time. When polishing is performed in this state, a difference in level between the electron-emitting region after polishing and the peripheral region occurs, and the amount of polishing is insufficient, and an impregnated cathode having a level difference of more than 10 μm,
Since the polishing amount is excessive and the surface up to the electron emitting portion becomes a non-porous surface, an impregnated cathode which does not emit electrons is produced at the same time.

In the method of manufacturing an impregnated cathode according to the present invention, even if the thickness of the porous body varies, the elastic member is deformed by interposing the elastic member between the back surface of the porous body and the polishing jig. However, the thickness variation of the porous body can be absorbed, and the front faces of the plurality of porous bodies can be simultaneously and uniformly brought into close contact with the polishing platen. Accordingly, a large number of pieces can be simultaneously polished to obtain a uniform polishing amount based on the front surface of the porous body, and the production efficiency is significantly improved.

In the method for producing an impregnated cathode according to the present invention, a sufficient amount of electron-emitting material is obtained in the cathode to obtain a stable electron emission characteristic in order to produce a monolithic porous sintered body. As a result, the life of the cathode can be prolonged. Furthermore, in the method for manufacturing an impregnated cathode according to the present invention, the manufacturing process is simple, so that the manufacturing cost can be reduced.

[0021]

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

First, an electron gun including an impregnated cathode manufactured by the method for manufacturing an impregnated cathode according to the present embodiment will be described.

FIG. 2 shows a schematic configuration of the above-described electron gun. The electron gun is applied to a cathode ray or an electron tube, and has a configuration including a cathode structure 100 and a grid group 200 including a first grid 5 and a second grid 6. The cathode structure 100 is made of an impregnated cathode 1 described in detail later, for example, molybdenum (Mo) or tantalum (T
a) a cap 2 made of a high melting point metal such as a), for example, a sleeve 3 made of tantalum and having a thickness of 20 μm, and a pure tungsten (W) wire or a tungsten alloy wire obtained by adding 2-3% rhenium (Re) to tungsten. And a heater 4 composed of a heating wire. The impregnated cathode 1A is mounted on a cap 2 and is fixed to a sleeve 3 via the cap 2. A heating heater 4 is provided in the sleeve 3, and is heated to, for example, 1000 ° C. by the heating heater 4 to activate the electron emitting material 1 a and emit electrons to the electron emission holes (beam holes) 5 a and 6 a. I do. Although not shown, the sleeve 3 is incorporated in the cathode ray tube by various supporting methods.

In this electron gun, the temperature of the cathode assembly 100 reaches about 1000 ° C. by the heater 4, and electrons (thermoelectrons) are emitted from the electron emitting material 1a. Among the emitted electrons, those that pass through the electron emission holes 5a of the first grid 5 and the electron emission holes 6a of the second grid 6 are effective electrons, and the effective electrons are output as an electron beam.
The light is emitted to a fluorescent screen (not shown).

Next, a specific method of manufacturing the impregnated cathode of the present invention will be described step by step with reference to FIG.

In the present embodiment, first, a slurry is prepared by mixing, for example, a tungsten powder having a particle size of 3 μm, which is a conductive substance, an organic binder and water using a stirrer. Next, using this slurry, granules of about 50 μm are produced, for example, by a spray dryer method. Subsequently, the granules are filled in a mold, for example, at a pressure of 5 tons / cm.
^The granules are sintered by pressing in step ² , for example, heating in a hydrogen reducing atmosphere to remove the organic binder, and further heating in vacuum, a hydrogen atmosphere, or an inert gas atmosphere at, for example, 1800 ° C. for 3 hours. Let it. In this way, as shown in FIG.
The porosity is constant at, for example, 25% in the porous body 11, and the front surface 20 has a cylindrical stepped portion 21 having a concave stepped portion 21 having a portion corresponding to the electron emission region 11 a as a bottom surface. The body 11 is manufactured. Here, the porous body 11
The surface on which the electron emission region 11a is located
The back surface is referred to as a back surface 30. This porous body 1
1 has a thickness of, for example, 0.65 mm, a diameter of, for example, 1.5 mm, a diameter of a portion corresponding to the electron emission region is, for example, 0.9 mm, a step difference from a portion corresponding to a peripheral region thereof,
That is, the size of the step portion 21 is, for example, 0.05 mm.

Here, the porosity of the porous body 11 is controlled by the pressure during press working, the atmosphere during sintering, the heating temperature, and the heating time. The porosity is preferably in the range of 16 to 32%. If the porosity is larger than 32%, the electron emitting material 1a impregnated in the porous body 11 is excessively evaporated and disappears quickly, so that the life as a cathode is shortened. %, The electron emitting material cannot be impregnated into the porous body 11 from the outside, and the supply of the electron emitting material to the cathode surface during operation is impaired, so that the electron emission characteristics are deteriorated. .

After producing the porous body 11 as a sintered body,
As shown in FIG. 1B, an elastic member 12 is interposed between the back surface 30 of the porous body 11 and the polishing jig 13, and a sintered body is formed on the surface of the polishing platen 14 on which the abrasive grains 15 are scattered. Porous body 1
The front surface 20 is applied, and a portion corresponding to a peripheral region of the electron emission region 11a is polished. As a result, in the peripheral region of the electron emission region 11a, the pores of the sintered body are crushed, and the porous body 1
A non-porous surface 11b is formed on one front surface. At this time, in order to fix the sample, when the elastic member 12 has an adhesive surface only on one side, the back surface 30 of the porous body 11 is adhered to the adhesive surface. When the elastic member 12 has an adhesive surface on both surfaces, the elastic member 12 may be adhered to either surface.

In this polishing, for example, one side of a sheet-like elastic member having a thickness of 1 mm made of an organic polymer having adhesive properties on both sides is bonded to a flat plate polishing jig made of, for example, stainless steel. Next, the back surface 30 of the porous body 11 is bonded to the elastic member. Thereafter, a diamond oil slurry having a particle size of, for example, 3 μm is dropped on a polishing platen 14 made of, for example, cast iron, and the front surface 20 of the porous sintered body 11 is applied to the polishing platen 14 at a pressure of, for example, 15 kg / mm ^2. The polishing is performed while rotating the polishing platen at a speed of 10 revolutions per minute.

As the sheet-like elastic member made of an organic polymer having adhesive properties on both surfaces used at this time, a silicone resin or a fluororesin is suitable, but not limited thereto. Further, in order to absorb the variation in the thickness of a large number of porous bodies and make the front surface of the porous body closely and uniformly contact with the polishing platen, the thickness of the elastic member is larger than the thickness of the porous body. Is preferred. If the thickness of the elastic member is extremely thin, it becomes difficult to deform by absorbing the thickness variation of the porous body, and the porous body front surface cannot be simultaneously and uniformly brought into close contact with the polishing platen. is there.

Further, the polishing jig and the polishing platen are not limited to those made of stainless steel and cast iron, but may be other parallel plane plates made of metal or ceramics. The material of the abrasive grains may be other than diamond, for example, metal oxide, carbide, or nitride. The grain size of the abrasive grains is 0.1.
It is preferably 1 μm or more.

Polishing is performed so that the size of the step 21 between the electron-emitting region 11a and its peripheral region is 10 μm or less, preferably 5 μm or less. This is because, as described above, if the step exceeds 10 μm, the electron emission characteristics become unstable or the distance between the impregnated cathode 1 and the first grid 5 can be accurately collated when assembling the electron gun. Because it becomes difficult.

In order to simultaneously polish a portion corresponding to the peripheral region of the front surface of a large number of porous bodies so that the step is reduced to, for example, 5 μm or less, the polishing amount (thickness) corresponds to a target polishing amount (thickness) in advance. A porous body (dummy sample) having a step and a front surface having a concave or convex shape is prepared, and polished until the concave or convex portion of the dummy sample disappears. That is, the step 2 of the porous body before polishing is performed.
Assuming that the size of 1 is 50 μm and its variation is ± 2 μm, an appropriate polishing amount is 47 μm to reduce the size of the step portion 21 to 5 μm or less. Therefore, 4
When a porous body (dummy sample) having a concave or convex front surface having a step of 7 μm is prepared and polished simultaneously with the porous body to be originally processed, the point at which the concave or convex portion of the dummy sample disappears is determined. This is the end point of the polishing process. According to this method, it is possible to easily determine the end point of the polishing process without paying attention to the disappearance of the concave portion or the convex portion of the dummy sample without performing the measuring operation during the polishing process, thereby improving the production efficiency. Becomes

Next, as shown in FIG. 1C, for example, barium carbonate (BaCO ₃ ) and calcium carbonate (CaC
O ₃ ) and aluminum oxide (Al ₂ O ₃ ) are mixed at a molar ratio of 4: 1: 1 by heating, melting and impregnating an electron-emitting substance 1a.
In a vacuum or hydrogen atmosphere, for example, about 170
By heating at a high temperature of 0 ° C., for example, impregnation is performed for about 3 minutes to complete the impregnated cathode 1.

In the impregnated cathode 1 produced, the pores of the sintered body are crushed on the non-porous surface 11b,
b is not impregnated with the electron emitting material 1a. Further, unnecessary emission of electrons from the non-porous surface 11b is suppressed.
Therefore, effective emission of electrons from the electron emission region 11a is performed stably and satisfactorily, and attachment of the electron emitting material 1a to the first grid 5 and the second grid 6 is suppressed. Furthermore, since the electron emitting material 1a is impregnated in the entire porous body 11 which is a sintered body having an integral structure, a sufficient amount of the electron emitting material 1a is obtained in the cathode to obtain stable electron emission characteristics. be able to. As a result, the life of the cathode can be extended.

As described above, according to the present embodiment, the non-porous surface 11b is formed by polishing the front surface of the porous body 11 other than the region serving as the electron emission region 11a. Unnecessary emission of electrons from the non-porous surface 11b during operation is suppressed, and evaporation of surplus particles of the electron emitting material 1a is prevented, so that the electron emitting material 1a is transmitted to the first grid 5 and the second grid 6. Adhesion can be suppressed. Therefore, stable electron emission characteristics can be obtained.

Further, since the porous body 11 has an integral structure, the manufacturing process is simple and the manufacturing cost can be reduced.

[0038]

EXAMPLES Further, specific examples of the present invention will be described.

In this example, first, a slurry was prepared by mixing tungsten powder having a particle size of 3 μm, an organic binder, and water using a stirrer. Then, using this slurry, spray dryer method is used.
Granules of about μm were produced. Next, the granules were filled in a mold, pressed at a pressure of 5 ton / cm ² , and then heated in a hydrogen reducing atmosphere to remove the organic binder. Further, it is heated at 1800 ° C. for 3 hours in a vacuum to have a thickness of 0.65 mm, a diameter of 1.5 mm, a diameter of a portion corresponding to an electron emission region of 0.9 mm, and a step with a portion corresponding to a peripheral region thereof, That is, the columnar porous body 11 having the concave portion with the step portion 21 having a size of 0.05 mm and the concave portion having the portion corresponding to the electron emission region as the bottom surface was manufactured. In addition, when the porosity of this porous body 11 was measured, it was 25%.

Subsequently, the back surface 30 of the porous body 11 was adhered to a polishing jig 13 which was a flat plate made of stainless steel and had a thickness of 1 m.
m on a silicone rubber sheet 12. Then, a diamond-based slurry having a particle diameter of 3 μm was dropped, and the front surface of the porous body 11 was placed on a polishing platen 14 made of cast iron.
A portion corresponding to the peripheral region of the electron emission region 11a was polished while rotating the polishing platen at a speed of 10 revolutions per minute while contacting with a pressure of 5 kg / mm ² . Thereby, in the peripheral region of the electron emission region 11a, the pores of the sintered body are crushed, and the non-porous surface 11b is formed on the surface of the porous body 11. A surface and a cross section of the porous body 11 are scanned with a scanning electron microscope (SE).
M: Scanninng Electron Microscopy), it was confirmed that the pores were crushed and disappeared on the non-porous surface 11b.

Then, for example, barium carbonate (B
a mixture of aCO ₃ ), calcium carbonate (CaCO ₃ ), and aluminum oxide (Al ₂ O ₃ ) having a molar ratio of 4: 1: 1. To obtain an impregnated cathode 1. Thereafter, an electron gun was assembled using the impregnated cathode 1 and mounted on a cathode ray tube.

As a comparative example of this embodiment, an impregnated cathode was manufactured under the same conditions as in the embodiment of the present invention except that the portion corresponding to the peripheral region of the front surface was not polished. An electron gun was assembled using the impregnated cathode and mounted on a cathode ray tube.

Using the thus obtained cathode ray tubes of Examples and Comparative Examples, a reliability test was performed for 5000 hours. As a result, in the cathode ray tube on which the impregnated cathode 1 manufactured by the manufacturing method according to the present embodiment was mounted, the change (drift amount) of the cutoff voltage was 20% or less of that of the comparative example. Further, in the cathode ray tube of the present embodiment, the generation of grid emission was able to be prevented. Furthermore, after the test,
When the cathode ray tubes of the example and the comparative example were disassembled and the attachment amount of barium and the like to the surfaces of the first grid and the second grid was confirmed, the attachment amount in the cathode ray tube of the present example was:
It was less than 20% of that of the comparative example. From the above results, it was found that the cathode ray tube (electron gun) obtained in the present example has high reliability of suppression in cathode cutoff voltage characteristics and grid emission and has excellent electron emission characteristics. .

Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to the above-described embodiments and examples, and can be variously modified. For example, in the above-described embodiment and examples, an example in which the porous body is formed of tungsten powder of a high melting point metal has been described. However, even if other materials are used, molybdenum (M
o) Being conductive, such as powder, capable of reducing an electron-emitting substance such as barium oxide, having an appropriate work function, operating temperature of a cathode (about 1000 ° C. for an impregnated type), and a process for producing a cathode ray tube or the like. Any material that satisfies the requirements of having a melting point that can withstand a temporary high aging temperature (about 1200 to 1300 ° C.) in vacuum and allowing porous sintering to be used.

Further, in the above-described embodiments and examples, the method of manufacturing the impregnated cathode 1 comprising the porous body 11 having an integral structure has been described, but the present invention is constituted by two or more porous bodies. The present invention can also be applied to the case of producing an impregnated cathode.

Further, in the above embodiment and examples,
Although the example in which the impregnated cathode 1 manufactured according to the present invention is applied to a cathode ray tube has been described, the invention can be widely applied to general electron tubes including microwave tubes and the like.

[0047]

As described above, in the method for manufacturing an impregnated cathode according to the present invention, a nonporous surface is formed by polishing a portion corresponding to a peripheral region of an electron emission region of a porous body. Therefore, emission of unnecessary electrons and the like from the peripheral region can be suppressed, and adhesion of a substance caused by an excessive electron emitting substance to the grid can be suppressed. Therefore, an effect is obtained that electrons are stably emitted from the electron emission region.

Further, since the electron emission region and the peripheral region are made of a porous material, the entire cathode is
A sufficient amount of electron emitting material can be stored to obtain stable electron emission characteristics. Therefore, the life of the cathode can be extended.

In particular, according to the method for manufacturing an impregnated cathode according to the eighth aspect, since a porous body made of a sintered body having an integral structure is used, the manufacturing process is simple and the manufacturing cost can be reduced. Can be planned.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of each step of a method for manufacturing an impregnated cathode according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of an electron gun using the impregnated cathode manufactured by the method for manufacturing an impregnated cathode according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impregnation type cathode 1a Electron emitting material 2 Cap 3 Sleeve 4 Heater 5 First grid 5a Electron emission hole of first grid 6 Second grid 6a Electron emission hole of second grid 11 Porous body 11a Electron emission area 11b Non-porous Surface 12 Elastic member 13 Polishing jig 14 Polishing surface plate 15 Abrasive grain 20 Front surface 30 Back surface 100 Cathode assembly 200 Grid group

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoki Fujii 6-1-112 Honcho, Tanashi-shi, Tokyo Inside Citizen Watch Co., Ltd. (72) Inventor Yoshiro Hirai 6-1-1, Honcho, Tanashi-shi, Tokyo No. Citizen Watch Co., Ltd. Tanashi Factory F-term (reference) 5C027 CC14 DD15

Claims (8)

[Claims] 1. A method for producing an impregnated cathode comprising a conductive porous body having an electron emission region and other peripheral regions on a front surface impregnated with an electron emitting material, comprising: After preparing a porous body having a portion corresponding to the electron emission region and a portion corresponding to the other peripheral region, an elastic member was interposed between the back surface of the porous body and the polishing jig, and abrasive grains were sprayed. By bringing the front surface of the porous body into contact with the polishing platen and polishing the portion corresponding to the peripheral area of the front surface,
A method for producing an impregnated cathode, comprising a step of making a surface of a peripheral region of a porous body a nonporous surface. 2. The method for producing an impregnated cathode according to claim 1, wherein the porous body has a stepped portion such that a portion corresponding to the electron emission region on the front surface becomes a bottom surface. 3. The impregnated cathode according to claim 1, wherein a step between the electron emission region on the front surface of the porous body and the other peripheral region is 10 μm or less. Manufacturing method. 4. The method for producing an impregnated cathode according to claim 1, wherein the elastic member is a sheet made of an organic polymer having tackiness on at least one surface. 5. The method for producing an impregnated cathode according to claim 1, wherein the polishing jig is a plate made of metal or ceramic having a parallel plane. . 6. The impregnated cathode according to claim 1, wherein the polishing platen is a plate made of metal or ceramics having a parallel plane. Manufacturing method. 7. The material of the abrasive grains is any one of a metal oxide, a carbide, a nitride, and diamond, and the grain size is 0.1.
Claim 1, Claim 2, wherein
The method for producing an impregnated cathode according to claim 3, 4, 5, or 6. 8. The conductive porous body according to claim 1, wherein the conductive porous body is a sintered body having an integral structure including at least one of tungsten and molybdenum metal powder. The method for producing an impregnated cathode according to claim 4, 5, 6, or 7.