Electric lamp and discharge devices: systems – High energy particle accelerator tube
Reexamination Certificate
1999-07-06
2002-02-26
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
High energy particle accelerator tube
C315S344000, C315S039000
Reexamination Certificate
active
06351087
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a microwave electrodeless discharge lamp apparatus in which microwaves oscillated by a magnetron excite luminescent materials to lead to discharge emission.
BACKGROUND OF THE INVENTION
Hitherto, this type of microwave electrodeless discharge lamp apparatus is disclosed in, for example, a publication of JP56-126250 A.
Namely, as shown in
FIG. 5
, a conventional apparatus includes a magnetron
14
generating microwaves, a cylindrical hollow container
2
made of metal mesh materials that cannot transmit microwaves but can transmit a light, a waveguide
15
propagating the generated microwaves to the hollow container
2
, a container
16
housing the magnetron
14
and the hollow container
2
.
The magnetron
14
is provided with an antenna
10
oscillating microwaves, a magnetron tube
17
substantially generating microwaves, a yoke
9
forming a magnetic path in such a manner that surrounds the magnetron tube
17
and a radiation fin
18
radiating heat that was generated at the magnetron tube
17
. The hollow container
2
includes an electrodeless discharge tube
5
that is supported and fixed by a supporting stick
4
made of silica glass and that is filled with luminescent materials. On a part of the wall of the container
16
, a cooling fan
19
is provided so as to cool the magnetron
14
.
Next, an operation of such a conventional microwave electrodeless discharge lamp apparatus will be explained.
Microwaves generated at the magnetron tube
17
are oscillated from the antenna
10
into the waveguide
15
, propagated inside the waveguide
15
and fed into the hollow container
2
by way of a feeding hole
11
of the waveguide
15
. The fed microwaves excite the luminescent materials sealed in the electrodeless discharge tube
5
to lead to discharge emission. When the magnetron
14
generates the microwaves, heat loss occurs in the magnetron tube
17
, thus raising the temperature of the magnetron tube
17
. As a result, an unstable operation or short lifetime of the magnetron
14
is caused. Therefore, in order to control the temperature of the magnetron tube
17
to such a temperature that does not affect the practical use of the application, the cooling fan
19
is operated to feed cooled air into the yoke
9
at about 1000 liter/min. Thus, a forced cooling of the magnetron tube
17
is carried out. Thereafter, the cooled air flows out from the apparatus by way of a ventilating hole
20
, the feeding hole
11
and the container
2
.
However, since such a conventional microwave electrodeless discharge lamp apparatus uses a forced cooling system using a fan, the apparatus is susceptible to the influence of the operation environment. There was a problem in that, for example, suction or accumulation of dust, dirt, insect, etc. by the apparatus may cause the deterioration of the magnetron tube or the cooling fan, etc. Consequently, the long lifetime of the apparatus cannot be realized.
Furthermore, there was another problem in that great noise occurs due to the rotation of the fan and air stream.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a long lifetime microwave electrodeless discharge lamp apparatus capable of inhibiting the generation of noise.
In order to achieve the above-mentioned object, the microwave electrodeless discharge lamp apparatus of the present invention includes a magnetron having a magnetron tube and a yoke that surrounds the magnetron tube, a container housing at least the magnetron tube, a propagation path in which microwaves oscillated by the magnetron are propagated, an electrodeless discharge tube sealing luminescent materials excited by the microwaves to emit light, wherein a space defined by the yoke is communicated with the inside of the container, and wherein a fluid is sealed in the container.
According to such a microwave electrodeless discharge lamp apparatus, heat generated in the magnetron tube is conducted in the fluid and the container and then radiated outside. Thus, the magnetron tube can stably be operated. Furthermore, the magnetron, etc. can be protected from the contamination of foreign substances causing the deterioration of the magnetron tube, etc. In addition, since the fluid circulation uses the thermal convection, a cooling of the magnetron tube can quietly be carried out.
It is preferable in the above-mentioned microwave electrodeless discharge lamp apparatus that the container is formed of good thermal conductors. With such a microwave electrodeless discharge lamp apparatus, heat of the fluids are easily radiated to the outside via the container.
Furthermore, it is preferable that the container is provided with a circulation path in which the fluid circulates.
Furthermore, it is preferable that the circulation path is formed by making the container a double wall structure. With such a microwave electrodeless discharge lamp apparatus, since the surface area of the container can be increased, the amount of the radiated heat from the fluid is increased, thus enabling the cooling efficiency of the magnetron tube to be improved.
Furthermore, it is preferable that the container is provided with a radiator radiating heat from the fluid. With such a microwave electrodeless discharge lamp apparatus, the amount of the radiated heat from the fluid is increased, thus further improving the cooling efficiency of the magnetron tube. Furthermore, the amount of fluid to be sealed can be reduced, which can lead to cost reduction, miniaturization and weight reduction of the apparatus.
Furthermore, it is preferable that the radiator is a conduit provided with a large number of radiation boards on its outer surface.
Furthermore, it is preferable that the radiator is formed of a plurality of thin conduits arranged in parallel. With such a microwave electrodeless discharge lamp apparatus, since the surface area of the container can be increased, the amount of the radiated heat from the fluid can be increased.
Furthermore, it is preferable that the fluid is insulating oil. Such a microwave electrodeless discharge lamp apparatus have excellent electric insulating property, fluidity, cold fluidity and metallic corrosion behavior or the like.
REFERENCES:
patent: 5216322 (1993-06-01), Fuchs
patent: 5811936 (1998-09-01), Turner et al.
patent: 5838108 (1998-11-01), Frank et al.
patent: 5977712 (1999-11-01), Simpson
patent: 6046545 (2000-04-01), Horiuchi et al.
patent: 0 035 898 (1981-09-01), None
patent: 05159875 (1993-06-01), None
Ichibakase Tsuyoshi
Katase Koichi
Seki Katsushi
Matsushita Electronics Corporation
Rosenthal & Osha L.L.P.
Tran Thuy Vinh
Wong Don
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