Electric lamp and discharge devices – Cathode ray tube – Plural beam generating or control
Reexamination Certificate
1999-07-21
2002-02-05
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
Cathode ray tube
Plural beam generating or control
C313S441000, C313S456000, C313S451000, C315S005330, C315S003500
Reexamination Certificate
active
06344709
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to an electron gun for microwave tubes such as traveling-wave tube (TWT) and Klystron.
2. Description of the Prior Art
Microwave tubes are used mainly as microwave amplifiers at earth stations and relay stations for microwave satellite communication. Recently, the microwave tubes are required to be small and light, as the earth stations and relay stations becomes compact and light in weight. Particularly, compact size and light in weight of the TWT for a repeater which is mounted in the satellite is of great importance.
A conventional hot cathode electron gun disclosed in JP 09115453 A, 1997 is shown in FIG.
4
. As shown in
FIG. 4
, hot cathode
102
is joined with stepped metal cylinder
118
which is joined with another stepped metal cylinder
117
which is further joined with focus electrode cylinder
119
. Cathode
111
, anode
113
, heater electrode
122
are insulated form one another by insulating cylinders
112
and
112
′, while cathode
111
is connected with focus electrode cylinder
119
and anode
113
is connected with a metal member consisted of metal cylinder
114
and anode electrode plate
115
. Further, one end
120
of a heater lead wire is connected with heater electrode
120
, while the other end
121
if the same is connected with metal cylinder
117
. The electron gun as explained above is sealed be sealing metal
123
and is connected with a not-shown RF frequency circuit by sealing plate
116
. Here, anode
113
is insulated from the not-shown RF circuit by using insulating cylinder
112
″.
Further, a conventional cold cathode electron gun also disclosed in the above-mentioned JP 09115453 A, 1997 is shown in FIG.
5
. As shown in
FIG. 5
, cold cathode
1
is joined with metal member
2
through plate
21
a
. Further, metal member
2
goes through insulating cylinder
3
which is joined with stepped metal cylinder
9
which mounts focus electrode
8
. Here, metal cylinder
9
is connected with a not-shown gate of cold cathode
1
by conductive wire
10
, while insulating cylinder
3
is joined with insulating cylinder
4
. Further, the not-shown gate is connected electrically with gate metal cylinder
7
by metallized layer
31
c
. Here, metallized layers
31
a
and
31
b
are used for obtaining electric connection at the connecting portion, respectively. The electron gun as explained above is contained in metal cylinder
5
. Further, metal cylinder
5
and insulating cylinder
4
are joined with stepped metal cylinder
6
.
However, the surrounding of the above-mentioned conventional hot electron guns must be furthermore insulated, because the insulating cylinders are stacked for the insulation of each electrode and high voltages are applied directly to the surrounding of the electron gun. Accordingly, insulating material must be fixed by using a jig of which diameter is greater than the surrounding.
On the contrary, it is not necessary to fix the insulating material around the external surrounding of the above-mentioned conventional cold cathode electron gun, because the surrounding is grounded electrically and each electrode is extracted along the axis of the electron gun. However, the above-mentioned conventional cold cathode electron gun has a disadvantage that its outer radius becomes great, due to the additional metal cylinder for obtaining electrical ground. Therefore, electron gun can not be made small and light.
Further, the structures of the above-mentioned hot and cold electron gun are so complex that it is difficult to manufacture them.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an electron gun, wherein its structure is simple and further electrodes can be extracted along its axis.
The hot cathode electron gun of the present invention comprises first stepped metal cylinder
201
which is joined with cathode
200
, second metal cylinder
202
which is joined with first stepped metal cylinder
201
, metal plate
221
which is joined with second metal cylinder
202
, insulating cylinder
220
which is joined with metal plate
221
, third metal cylinder
260
which is joined with the outer surface of insulating cylinder
220
, fourth metal cylinder
210
which is joined with third metal cylinder
260
, stepped insulating cylinder
250
which is joined with fourth stepped metal cylinder
210
, and fifth metal cylinder
270
which is joined with stepped insulating cylinder
250
.
In this electron gun, fifth metal cylinder
270
is grounded electrically. Further, cathode lead wire, anode lead wire, heater lead wire are extracted along the axis of the gun.
In place of the hot cathode, a cold cathode is also applicable, and cathode lead wire, anode lead wire, and gate lead wire are extracted along the axis of the gun.
In the electron gun of the present invention, an insulating cylinder is used as a vacuum envelope, and the electrodes are extracted along the gun axis.
According to the present invention, it is not necessary to insulate the surrounding of electron gun, because an insulating cylinder is used as a vacuum envelope and the electrodes are extracted along the axis of the electron gun. Therefore, the electron gun can be made small and light.
Further, the insulating cylinder as a vacuum envelope operates also as a jig for filling up insulating material around the high voltage terminals of the electrodes, because the terminals are positioned inside the insulating cylinder. Therefore, conventional jigs become needless. Accordingly, manufacturing processes of the electron gun are simplified.
REFERENCES:
patent: 2814751 (1957-11-01), Murdock et al.
patent: 3979634 (1976-09-01), Jaillet et al.
patent: 4376257 (1983-03-01), Miyazaki et al.
patent: 5534747 (1996-07-01), Carruthers
patent: 5629582 (1997-05-01), Dobbs
patent: 30-6211 (1953-10-01), None
patent: 56-28439 (1981-03-01), None
patent: 1-142147 (1989-09-01), None
patent: 02-5866 (1990-01-01), None
patent: 02-160400 (1990-06-01), None
patent: 4-215233 (1992-08-01), None
patent: 5-250998 (1993-09-01), None
patent: 9-115453 (1997-05-01), None
Guharay Karabi
Patel Nimeshkumar D.
Sughrue & Mion, PLLC
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