JPH07249367A - Electron tube having impregnated cathode - Google Patents

Abstract

PURPOSE:To provide an electron tube having an impregnated cathode that can be quickly recovered from the dissipation of complex metal layers due to ionic impacts by enabling the impregnated cathode to operate and pass high- density current at low workable temperatures. CONSTITUTION:In an electron tube having an impregnated cathode comprising a porous base 14 made of a metal with a high melting point and having its porous part impregnated with an electron-emitting material 15 containing barium (Ba), a first complex thin-film layer 19 composed chiefly of tungsten (W) or molybdenum (Mo) and scandium (Sc), and a second complex thin-film layer 20 composed chiefly of tungsten (W) or molybdenum (Mo), scandium (Sc), and oxygen (O), are stacked on the electron-emitting surface of the porous base 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron tube equipped with an impregnated cathode, and more particularly to a cathode ray tube, an image pickup tube and a traveling wave equipped with the impregnated cathode capable of operating at a low temperature and capable of passing a high density current. Regarding electronic tubes such as tubes.

[0002]

2. Description of the Related Art Generally, an impregnated cathode used for electron tubes such as cathode ray tubes, image pickup tubes and traveling wave tubes has a high heat resistant porous substrate made of a high melting point metal such as tungsten (W).
This porous substrate has a structure in which pores are impregnated with an electron emitting substance containing barium (Ba). Further, the impregnated cathode having such a structure usually needs to be operated in a considerably high temperature state of 1100 ° C. or higher, so that it is far from practical use.

On the other hand, in the impregnated cathode, various means for lowering the usable operating temperature have already been proposed. The first of these proposals is Japanese Patent Publication No. 47-2134.
No. 3, which discloses osmium on the surface of the impregnated cathode.
It is a means for coating a ruthenium (Os-Ru) alloy or the like. Although this means has already been put to practical use in part, the usable operating temperature in the impregnated cathode is
Since it is still as high as about 1000 ° C., it is another one for practical use, and this high operating temperature is also a major obstacle to practical use.

The second of the above proposals is disclosed in Japanese Patent Laid-Open No.
1-135226, the surface of the impregnated cathode is covered with tungsten (W) and scandium oxide (Sc ₂ O ₃ ) instead of coating the surface of the impregnated cathode with an osmium-ruthenium (Os-Ru) alloy or the like. ) Is deposited by a sputter deposition method, or tungsten (W) and scandium oxide (S) are used instead of the sputter deposition method.
This is a means for baking a raw material powder made of c ₂ O ₃ ) to deposit a thin film as a sintered body. According to this means, a composite metal layer composed of barium (Ba), scandium (Sc) and oxygen (O) having a low work function is formed on the surface of the impregnated cathode during operation of the impregnated cathode. By forming the, the usable operating temperature of the impregnated cathode is
About 150 to 200 ° C higher than the first one proposed above
It is possible to reduce the degree to some extent, and as far as the operating temperature is concerned, the obstacle of the first proposed can be removed.

[0005]

In general, the impregnated cathode used in an electron tube has a low work function metal composite layer formed on the surface of the impregnated cathode, even if it partially disappears due to ion bombardment. The lost part is quickly repaired,
Regeneration is an important factor, and particularly regeneration of scandium (Sc) is required for regeneration of the metal composite layer.

By the way, in both the first and second proposals, a monomolecular layer is formed on the surface of the impregnated cathode, so that a high current density can be passed through the impregnated cathode. It is a thing. However, the monomolecular layer formed here is extremely weak against ion bombardment and easily disappears.

That is, the second one proposed above has the great advantage that a relatively low operating temperature can be obtained, but barium () having a low work function formed on the surface of the impregnated cathode. When a part of the composite metal layer containing Ba), scandium (Sc), and oxygen (O) as main components is lost by ion bombardment, at the operating temperature, the regeneration speed of the disappeared portion, that is, scandium. The reproduction speed of (Sc) is very slow, and quick recovery cannot be expected. When the composite metal layer disappears due to ion bombardment, sufficient electron emission ability cannot be obtained at a low operating temperature in the disappeared portion, and as a result, a relatively low usable operating temperature characteristic cannot be utilized. I have a problem.

The present invention eliminates the above-mentioned problems, and an object thereof is to enable operation at a low temperature which can be used and to conduct high-density current, and to promptly eliminate a composite metal layer due to ion bombardment. Another object of the present invention is to provide an electron tube having an impregnated cathode that can be recovered.

[0009]

To achieve the above object, the present invention is to impregnate a porous substrate made of a refractory metal and an electron emitting substance containing barium (Ba) in the pores of the porous substrate. In an electron tube including an impregnated cathode configured as described above, a first mixed thin film layer containing tungsten (W) or molybdenum (Mo) and scandium (Sc) as a main component, and tungsten on the electron emission surface of the porous substrate. (W) or molybdenum (Mo), scandium (Sc), and a second mixed thin film layer containing oxygen (O) as a main component are provided in a laminated arrangement.

In this case, the first mixed thin film layer is preferably formed to have a thickness of 0.1 to 50 μm, and the second mixed thin film layer is preferably formed to have a thickness of 60 to 900 nm. Is formed.

[0011]

According to the above means, the first mixed thin film layer containing tungsten (W) or molybdenum (Mo) and scandium (Sc) as main components is arranged on the electron emission surface of the porous substrate in the impregnated cathode. , On top of that, tungsten (W) or molybdenum (Mo), scandium (S
The second mixed thin film layer containing c) and oxygen (O) as main components is arranged.

By thus forming and arranging the first mixed thin film layer, barium (Ba), scandium (Sc), oxygen (O) having a low work function is formed on the surface of the second mixed thin film layer. It has been confirmed that a composite metal layer containing as a main component is formed, and that the composite metal layer is rapidly regenerated even if it disappears due to ion bombardment.

That is, the first mixed thin film layer is composed of a mixed metal thin film layer containing a refractory metal and scandium (Sc) as main components. On the electron emission surface of the porous substrate, scandium (S
It works so as to rapidly diffuse and supply c). When the refractory metal is mainly composed of either tungsten (W) or molybdenum (Mo), or one containing tungsten (W) and molybdenum (Mo), the scandium (Sc) is diffused. The supply effect becomes remarkable.

[0014]

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

FIG. 1 is a sectional structural view showing the outline of the constitution of an embodiment of an electron tube provided with an impregnated cathode according to the present invention, and showing an example in the case of a color picture tube as the electron tube.

In FIG. 1, 1 is a panel section, 2 is a funnel section, 3 is a neck section, 4 is a fluorescent surface, 5 is a shadow mask, 6 is a magnetic shield, 7 is a deflection yoke, 8 is a purity adjusting magnet, and 9 is a magnet. Is a center beam static convergence adjustment magnet, 10 is a side beam static convergence adjustment magnet, 11 is an electron gun, and 12 is an electron beam.

The tubular body that constitutes the color picture tube is
It comprises a panel section 1 arranged on the front side, a neck section 3 accommodating the electron gun 11, and a funnel section 2 arranged between the panel section 1 and the neck section 3. A fluorescent surface 4 is arranged and formed on the inner surface of the panel portion 1, and a shadow mask 5 is arranged so as to face the fluorescent surface 4. A magnetic shield 6 is provided inside the connecting portion of the panel portion 1 and the funnel portion 2.
Is provided, and the deflection yoke 7 is provided outside the connection portion of the funnel portion 2 and the neck portion 3. On the outside of the neck portion 3, a magnet 8 for adjusting the purity, a magnet 9 for adjusting the center beam static convergence, and a magnet 10 for adjusting the side beam static convergence.
Are arranged side by side, and the three electron beams 12 projected from the electron gun 11 are deflected in a predetermined direction by the deflection yoke 7, and then reach the picture element of the corresponding color on the fluorescent surface 4 through the shadow mask 5. Is configured to.

In this case, the image display operation in the color picture tube having the above-mentioned structure is exactly the same as the image display operation in the known color picture tube, and therefore the description of the image display operation in this color picture tube is omitted.

Next, FIG. 2 is an enlarged sectional view showing the impregnated cathode used in the electron gun 11 of the color picture tube shown in FIG.

In FIG. 2, 13 is a cathode pellet, and 14
Is a porous substrate of refractory metal, 15 is an electron emitting material, 16
Is a barrier layer, 17 is a sleeve, 18 is a heater, and 19 is a first
2 is a mixed thin film layer, 20 is a second mixed thin film layer, and 21 is a composite metal layer.

The cathode pellet 13 contains a porous substrate 14 of a refractory metal made of tungsten (W) or molybdenum (Mo) and at least barium (Ba) or oxygen (O). The electron emission material 15 is impregnated into the pores of the. Sleeve 1
The cathode pellet 13 is formed on the upper side of the inside of 7 through the barrier layer 16.
Is also held, and a heater 18 is similarly arranged below the inside of the sleeve 17. Above the cathode pellet 13,
First mixed thin-film layer 19 containing tungsten (W) or molybdenum (Mo) and scandium (Sc) as main components
Are formed on the first mixed thin film layer 19, and tungsten (W) or molybdenum (Mo),
A second mixed thin film layer 20 containing scandium (Sc) and oxygen (O) as main components is formed. In this case, the first mixed thin film layer 19 and the second mixed thin film layer 20 are formed by a sputter deposition method, an ion plating method, a vacuum deposition method, a CVD (chemical vapor deposition method) or the like. The composite metal layer 21 includes barium (Ba), scandium (Sc),
A second mixed thin film layer which is an extremely thin layer having a thickness of about one to several molecular layers containing oxygen (O) as a main component and which is heated when the impregnated cathode is heated by energizing the heater 18. Two
It is formed on the surface of 0.

A process in which the composite metal layer 21 is formed when the heater 18 is energized in the above structure will be described. However, in this case, the refractory metal porous substrate 14 is tungsten (W), and barium (Ba) is used.
The electron emission material 15 containing oxygen and oxygen (O) is barium aluminate (barium aluminate) (Ba ₃ Al ₂ O ₆ ), and the first mixed thin film layer 19 includes tungsten (W) and scandium (Sc). The second mixed thin film layer 20 will be described as a mixed metal composed of tungsten (W), tungsten oxide (WO ₃ ), and scandium oxide (Sc ₂ O ₃ ).

First, when the heater 18 is energized to heat the impregnated cathode, metal scandium (Sc) is liberated from the first mixed thin film layer 19, and the liberated metal scandium (Sc) is first and second. Second mixed thin film layer 19, 20
It is diffused inside and supplied to the surface of the second mixed thin film layer 20. At this time, in the second mixed thin film layer 20, tungsten oxide (WO ₃ ) and scandium oxide (Sc ₂
O ₃ ) reacts as shown in the following formula (1).

3WO ₃ + Sc ₂ O ₃ → Sc ₂ W ₃ O ₁₂ (1) On the other hand, inside the cathode pellet 13, tungsten (W) which is a refractory metal and barium aluminate (Ba ₃ Al ₂ O ₆ ) reacts as shown in the following formula (2).

(2/3) Ba ₃ Al ₂ O ₆ + (1/3) W → (1/3) BaWO ₄ + (2/3) BaAl ₂ O ₄ + Ba (2) The generated barium (Ba ) Partially diffuses in the first and second mixed thin film layers 19 and 20, while the other partially scandium tungstate (scandium tungstate) (Sc ₂ W ₃ O ₁₂ ) and the following formula ( React as shown in 3).

Sc ₂ W ₃ O ₁₂ + 3Ba → 3BaWO ₄ + 2Sc (3) Here, barium (Ba) and scandium (Sc) diffused to the surface of the second mixed thin film layer 20 are heat of the electron emitting substance 15. The second mixed thin film layer 20 is combined with oxygen (O) generated by decomposition and oxygen (O) in the atmosphere.
Very thin barium (Ba), scandium (Sc), oxygen (O) with a thickness of about one to several molecular layers on the surface of
The composite metal layer 21 containing as a main component is formed in a short time. The composite metal layer 21 containing barium (Ba), scandium (Sc), and oxygen (O) as the main components has a small electron emission work function of 1.2 eV, so that a high electron emission capability is obtained, whereby an impregnated type is obtained. It is possible to significantly reduce the usable operating temperature of the cathode.

In the impregnated cathode disclosed in JP-A-61-132626, which does not have the first mixed thin film layer 19, barium (Ba), scandium (Sc), oxygen ( When a part of the composite metal layer containing O) as a main component disappears, to reproduce the composite metal layer,
When operating temperature is low, barium (Ba) or oxygen (O)
Regenerates relatively quickly, but scandium (S
c) could not be regenerated until a long time had passed.

On the other hand, in the impregnated cathode according to the present embodiment in which the first mixed thin film layer 19 is provided below the second mixed thin film layer 20, scandium (Sc) is used even when the operating temperature is low. ) Is liberated from the first mixed thin film layer 19 and sufficiently supplied to the surface of the second mixed thin film layer 20 by diffusion, so that barium (B
a), scandium (Sc), even if a part of the composite metal layer 21 containing oxygen (O) as a main component disappears, at the same time as the disappearance, scandium (Sc) and other barium (B).
A) and oxygen (O) are rapidly supplied, and quick regeneration is performed.

When recovering the disappearance of the composite metal layer 21 due to ion bombardment, the thickness of the first mixed thin film layer 19 is selected in the range of 0.1 to 50 μm, and the second mixed thin film layer is selected. If the thickness of 20 is selected in the range of 60 to 900 nm, its recovery function can be sufficiently exerted.

Next, an example of steps for manufacturing the impregnated cathode shown in FIG. 2 will be described.

First, tungsten (W) powder having an average particle size of 5 μm was gradually stirred to evaporate acetone in an acetone solution containing 1.25% of polymethylmethacryl as a binder. Granulate the powder of W). Next, the tungsten (W) granules obtained here are sized by a sieve of about 200 mesh, press-molded, pre-sintered in hydrogen, and subsequently main-sintered in vacuum, A porous substrate 14 having a porosity of about 28% is prepared. Next, in the pores of this porous substrate 14, 4
An electron emitting substance 15 having a composition of BaO.CaO.Al ₂ O ₃ is impregnated with heating and melting, and then the excess electron emitting substance 15 is removed to prepare an impregnated cathode pellet 13. Subsequently, the impregnated cathode pellet 13 is inserted into the cup-shaped barrier layer 16 made of molybdenum (Mo) and further combined with the sleeve 17 containing the heater 18 to form the main body of the impregnated cathode. .

Next, a sputtering apparatus is prepared which is capable of forming multiple layers of different films continuously at the same time as multiple elements, and scandium (Sc), tungsten (W), tungsten oxide ( WO ₃ ) and scandium oxide (Sc ₂ O ₃ ) are attached. Then, first, two targets are simultaneously sputtered on the surface of the cathode pellet 13 of the main body of the impregnated cathode by using each target of scandium (Sc) and tungsten (W) to obtain tungsten (W) and scandium (W). A first mixed thin film layer 19 containing Sc) as a main component is formed. Subsequent to the formation, ternary simultaneous sputtering is performed on the first mixed thin film layer 19 using each target of tungsten (W), tungsten oxide (WO ₃ ) and scandium oxide (Sc ₂ O ₃ ). done, tungsten (W), tungsten oxide (WO _3), scandium oxide (Sc ₂
A second mixed thin film layer 20 of O ₃ ) is formed. In forming these films, argon (Ar) was used as the discharge gas in all cases, and the first mixed thin film layer 19 was set to direct current (D).
C) By sputtering, the second mixed thin film layer 20 was formed by radio frequency (RF) sputtering.

In the film formation, after the first mixed thin film layer 19 is deposited to a thickness of about 7 μm, the second mixed thin film layer 20 is continuously deposited to a thickness of about 200 nm. In this case, the thicknesses of the thin film layers 19 and 20 during sputtering are adjusted by adjusting the sputtering power and the sputtering time, respectively. Further, the composition of each of the mixed thin film layers 19 and 20 is performed by adjusting the input power ratio for each target. In this case, for the second mixed thin film layer 20, solution emission spectroscopy (ICP)
As a result of examining the composition by the method, the weight ratio of scandium / tungsten (Sc / W) is 0.029 to 0.03.
In the range of 6, it was found to have excellent electron emission characteristics. The thickness of the first mixed thin film layer 19 is
In the range of 0.1 to 50 μm, the second mixed thin film layer 2
It was found that when the thickness of 0 is in the range of 60 to 900 nm, almost the same recovery characteristics for disappearance of the composite metal layer 21 are exhibited, although slight differences are observed. Then, even if the respective thicknesses of the first mixed thin film layer 19 and the second mixed thin film layer 20 are thinner or thicker than the above range, the recovery characteristic tends to deteriorate.

FIG. 3 shows this embodiment, the above-mentioned Japanese Patent Laid-Open No. 61-13.
FIG. 6 is a characteristic diagram showing the relationship between the activation time and the emission current density in each impregnated cathode disclosed in Japanese Patent Publication No. 526 and Japanese Patent Publication No. 47-21343.

In FIG. 3, the vertical axis is A (ampere) / c.
The emission current density represented by m ² , the horizontal axis is the activation time represented by h (hour), the curve is the characteristic of the impregnated cathode of this example, and the curve is disclosed in the above-mentioned JP-A-61-132626. The characteristics and curve of the impregnated type cathode are
These are characteristics of the impregnated cathode disclosed in 1343.

The characteristics shown in FIG. 3 are obtained by arranging two parallel plate type electrodes consisting of an anode and a cathode in a high vacuum container having a vacuum degree of 10 −7 Pa class, and After activating the impregnated cathode by heating the operating temperature to 1150 ° C, the operating temperature of the impregnated cathode is lowered to 850 ° C (for curves and curves) or 1000 ° C (for curves), and the anode is positively charged. The emission current from the cathode was measured when the pulse voltage was applied.

In this case, as shown by the curve, the impregnated cathode disclosed in Japanese Patent Laid-Open No. 61-13526 requires a long time until the emission current density is saturated even if the activation is repeated. However, as shown by the curve, the impregnated cathode of this example has a short activation time until the maximum emission current density is reached, and as shown by the curve, it has already been partially used. Said Japanese Patent Publication No. 47-21343
It can be seen that it is as short as the activation time of the impregnated cathode disclosed in the publication. Further, the emission current characteristics of the impregnated cathode of this example shown by the curve are superior to the emission current characteristics of the known impregnated cathode shown by the curve and the curve, and moreover, stability and reproducibility are good. It is a thing.

Next, FIG. 4 shows this embodiment and the above-mentioned Japanese Patent Laid-Open No.
Japanese Patent Publication No. 47-21, which is disclosed in Japanese Patent No.
FIG. 34 is a characteristic diagram showing the relationship between the heating time after ion bombardment and the emission current density in each impregnated cathode disclosed in No. 343.

In FIG. 4, the vertical axis is A (ampere) / c.
The emission current density represented by m ² , the horizontal axis is the heating time after ion bombardment represented by s (seconds), the curve is the characteristic of the impregnated cathode of the present example, and the curve is the one described in JP-A-61-
The characteristics and curves of the impregnated cathode disclosed in No. 13526 are the characteristics of the impregnated cathode disclosed in Japanese Patent Publication No. 47-21343.

The characteristics shown in FIG. 4 are as follows. Argon (Ar) gas is introduced into the above-mentioned high vacuum container, and argon (Ar) is introduced on the electron emission surface of the impregnated cathode activated by using an ion gun. Ar) ion irradiation, the recovery characteristics of the electron emission state are measured, and the recovery characteristics of the electron emission state are measured by Odier analysis, and the recovery characteristics of the scandium (Sc) element on the surface of the electron emission surface are measured. This is a study of the playback status.

Also in this case, as shown by the curve, the impregnated cathode disclosed in JP-A-61-132625 has a considerably long activation time until the maximum emission current density is reached after ion bombardment. On the other hand, as shown by the curve, the impregnated cathode of this example has a short activation time after the ion bombardment until the maximum emission current density is reached. -21343
It is shorter than the activation time of the impregnated cathode disclosed in No. Further, the emission current characteristic of the impregnated cathode of this example shown by the curve is superior to the emission current characteristic of the known impregnated cathode shown by the curve or the curve, and it is a practical impregnated cathode. You can Further, according to the above-mentioned Ogier analysis, the impregnated cathode of this example shows that the composite metal having a low work function, which is as thin as a monolayer formed on the surface of the second mixed thin film layer 20 and has a low work function. It was confirmed that the layer 21 was regenerated within a short period of time, as was the recovery of its electron emission properties within a short period of time.

As described above, the impregnated cathode according to this embodiment has a low operating temperature characteristic that can be used, and the composite metal layer 21 having a low work function can be rapidly regenerated. It can withstand practical use as an impregnated cathode for an electron tube and can be put to practical use.

In the above-mentioned embodiment, the refractory metal porous substrate 14 is tungsten (W), and the electron emitting material 15 containing barium (Ba) and oxygen (O) is
Barium aluminate (Ba ₃ Al ₂ O ₆ ) and second
The mixed thin film layer 20 of No. ₂ described above uses a mixed metal composed of tungsten (W), tungsten oxide (WO ₃ ) and scandium oxide (Sc ₂ O ₃ ). The porous substrate 14, the electron emission material 15, and the second mixed thin film layer 20 are not limited to those having the above-described compositions, and molybdenum (Mo) is used for other compositions, for example, for the porous substrate 14 of a refractory metal. The electron-electron emission material 15 may also be used as barium (B
Other compositions may be used as long as they are mainly composed of a) and oxygen (O), and tungsten (W) or molybdenum (Mo) is also used for the second mixed thin film layer 20. Needless to say, other compositions may be used as long as they contain scandium (Sc) and oxygen (O) as main components.

In the above-mentioned embodiment, the preferable ranges are shown for the thicknesses of the first mixed thin film layer 19 and the second mixed thin film layer 20, respectively. The thicknesses of 19 and 20 are not limited to the above-mentioned preferable range, and may be set to a thickness close to the preferable range if the reproducing function of the composite metal layer 21 is somewhat sacrificed. Of course.

Further, in the above-mentioned embodiments, the case where the impregnated cathode is the cathode of the color picture tube has been described, but the impregnated cathode of the present invention is not limited to the case of being used for the color picture tube. The present invention can be similarly used for other electron tubes, for example, a monochrome display tube (Braun tube), an imaging tube, a traveling wave tube, and the like.

[0046]

As described above, according to the present invention, the electron emitting surface of the porous substrate in the impregnated cathode contains tungsten (W) or molybdenum (Mo) and scandium (Sc) as the main components. 1 mixed thin film layer is arranged,
On top of that, tungsten (W) or molybdenum (M
o), scandium (Sc) and a second mixed thin film layer containing oxygen (O) as main components are arranged, and barium (Ba) and scandium (Sc) having a low work function are provided on the surface of the second mixed thin film layer. , A composite metal layer containing oxygen (O) as a main component is formed. The composite metal layer having a low work function has a low operating temperature characteristic that can be used, can pass a current having a high current density, and even if it disappears due to ion bombardment, Since regeneration is carried out quickly, there is an effect that an impregnated cathode for an electron tube can be obtained which can be sufficiently used and can be put into practical use.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing the outline of the configuration of an embodiment of an electron tube including an impregnated cathode according to the present invention.

FIG. 2 is an enlarged cross-sectional configuration diagram showing an impregnated cathode used in the electron tube shown in FIG.

FIG. 3 is a characteristic diagram showing a relationship between activation time and emission current density in the impregnated cathode of the embodiment shown in FIG.

FIG. 4 is a characteristic diagram showing the relationship between the heating time after ion bombardment and the emission current density in the impregnated cathode of the embodiment shown in FIG.

[Explanation of symbols]

1 Panel Part 2 Funnel Part 3 Neck Part 4 Fluorescent Surface 5 Shadow Mask 6 Magnetic Shield 7 Deflection Yoke 8 Purity Adjusting Magnet 9 Center Beam Static Convergence Adjusting Magnet 10 Side Beam Static Convergence Adjusting Magnet 11 Electron Gun 12 Electron Beam 13 Cathode Pellet 14 Porous substrate of refractory metal 15 Electron emission material 16 Barrier layer 17 Sleeve 18 Heater 19 First mixed thin film layer 20 Second mixed thin film layer 21 Composite metal layer

Claims (3)

[Claims] 1. An electron tube provided with a porous substrate made of a refractory metal and an impregnated cathode formed by impregnating pores of the porous substrate with an electron-emitting substance containing barium (Ba). A first mixed thin film layer containing tungsten (W) or molybdenum (Mo) and scandium (Sc) as main components, and tungsten (W) or molybdenum (Mo), scandium (Sc), and oxygen ( An electron tube comprising an impregnated cathode, wherein a second mixed thin film layer containing O) as a main component is laminated and arranged. 2. The first mixed thin film layer comprises 0.1 to 5
The electron tube having the impregnated cathode according to claim 1, wherein the electron tube is formed to a thickness of 0 μm. 3. The second mixed thin film layer comprises 60 to 90.
An electron tube comprising the impregnated cathode according to claim 1, wherein the electron tube is formed to have a thickness of 0 nm.