Refrigeration – Structural installation – With electrical component cooling
Reexamination Certificate
2002-10-04
2004-03-02
Doerrler, William C. (Department: 3744)
Refrigeration
Structural installation
With electrical component cooling
C062S003700, C361S688000, C361S716000
Reexamination Certificate
active
06698224
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electronic apparatus having at least two electronic parts operating at different temperatures, respectively; and, more particularly, to an electronic apparatus employing a cooling structure for cooling at least two electronic parts operating at different cooling temperatures, respectively.
BACKGROUND OF THE INVENTION
More than two electronic parts or electronic units are usually used in a single electric circuit of an electronic apparatus, e.g., a communications apparatus. Such electronic parts or units of the electronic apparatus can operate at different operating temperatures, respectively, and such being the case, there may exist electronic parts that need to be operated at low or ultra low temperatures.
FIG. 1
shows an electronic apparatus
1
employing a conventional cooling structure for cooling such electronic parts operating at low temperatures. The electronic apparatus
1
includes a thermally insulated vacuum vessel
2
and a cold head
4
disposed therein. The cold head
4
is thermally connected with a cooler
8
via a supporting column
3
, which hermetically passes through a lower portion of the thermally insulated vessel
2
. The supporting column
3
further serves as a passageway for circulating coolant of the cooler
8
between the cold head
4
and the cooler
8
.
Mounted on the cold head
4
are a superconducting filter
10
, an isolator
12
, and a low noise amplifier
14
, which are electrically connected together via a cable
16
. One end of the cable
16
is electrically connected to an external electronic apparatus (not shown), e.g., a communications apparatus, via a first connector
18
. The other end thereof is coupled to an external antenna
22
via a second connector
20
, wherein each of the connectors
18
,
20
is of a thermal insulator.
A signal received by the antenna
22
is inputted to the superconducting filter
10
via the second connector
20
and the cable
16
and then passes through the isolator
12
and the low noise amplifier
14
in sequence. The signal is finally transmitted to the external electronic apparatus via the cable
16
and the first connector
18
. Herein, the isolator
12
serves to prevent the superconducting filter
10
from being affected by an input impedance of the low noise amplifier
14
.
The superconducting filter
10
is a cryogenic module that can withstand a cooling at a cryogenic temperature, e.g., about 60 K or lower. The cooler
8
cools the cold head
4
, which is in contact with the superconducting filter
10
at about 60 K, thereby cooling the superconducting filter
10
to an equivalent temperature of about 60 K at which the superconducting filter
10
can properly function. Herein, the isolator
12
and the low noise amplifier
14
, which are adjacent to the superconducting filter
10
, are also in contact with the cold head
4
, having the equivalent cooling temperature of 60 K.
However, such cooling condition may have an adverse effect on a non-cryogenic electronic part, more specifically, an electronic part having a higher warranted operation temperature. Normally, the isolator
12
is usually a non-cryogenic type having a warranted operation temperature of about 200 K. Thus when operated and cooled at a cryogenic temperature, an erroneous operation or even a breakage thereof may occur. Employing a cryogenic isolator, instead of the non-cryogenic type, can avoid the problems mentioned above in the prior art, but the cryogenic isolator bears high cost and, therefore, is rarely used.
Referring to
FIG. 2
, another exemplary prior art communications apparatus, more specifically, a receiver
11
having a cooling structure will be explained. Like numerals represent like parts in
FIGS. 1 and 2
and thus a detailed description thereof will be omitted.
The receiver
11
includes a thermally insulated vacuum vessel
2
and a cold head
4
disposed therein. The cold head
4
is thermally connected with a cooler
8
, which is disposed outside of the thermally insulated vessel
2
. Mounted on the cold head
4
are a band pass filter
24
and a low noise amplifier
14
. The band pass filter
24
serves to select a desired band signal and the low noise amplifier
14
serves to amplify the selected band signal to a desired level.
The band pass filter
24
is usually a superconducting filter having a component made of a superconducting material, preferably, a high temperature superconducting material, such as bismuth (Bi)-based, titanium (Ti)-based, lead (Pb)-based or Yttrium (Y)-based copper oxide. The high temperature superconducting filter (HTSF) is of a micro-stripe type thin film HTSF or a common resonator type thick film HTSF.
The power for the low noise amplifier
14
is supplied from an external power source (not shown) via a power terminal
28
. The low noise amplifier
14
is accommodated inside the thermally insulated vessel
2
for the purpose of noise reduction. In such a case, a cryogenic low noise amplifier (CLNA) is preferably used. A Dewar vessel can be advantageously employed as the thermally insulated vessel
2
.
The cooler
8
cools the band pass filter
24
at a cryogenic temperature to realize a superconducting state thereof, wherein power is supplied to the cooler
8
via an external power source terminal
26
. The cooler
8
is usually a cryocooler, which repeatedly compresses and expands helium gas during a heat exchange cycle so that cryogenic temperatures in the range of 10s of Kelvins can be obtained. In general, a pulse type Sterling cycle cryocooler of a small size is used for the cooler
8
.
The cryogenic temperature of the band pass filter
24
and the low noise amplifier
14
provides several advantages in that: a thermal noise thereof can be reduced; an insert loss of the band pass filter
24
can be reduced; and an attenuation characteristic of the band pass filter
24
can be greatly improved. As a result, by using the receiver
11
of
FIG. 2
, an output signal of a desired carrier-to-noise (C/N) power ratio can be obtained even for a low level input signal.
Such a cryogenic low noise amplifier operable at the cryogenic temperature is costly. To reduce the cost, a non-cryogenic low noise amplifier may be disposed outside the thermally insulated vessel in replacement of the cryogenic low noise amplifier. However, an elongated signal passage between the low noise amplifier and the band pass filter increases loss of signals transmitted therebetween.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the present invention to provide an electronic apparatus employing a cooling structure for cooling at least two electronic parts operating at different temperatures.
In accordance with a preferred embodiment of the present invention, there is provided an electronic apparatus having at least two electronic parts which operate at different temperatures, respectively, including: a thermally insulated vessel having a cooling part therein; a first electronic part disposed inside the vessel; and a second electronic part disposed inside the vessel, wherein the second electronic part is spaced apart from the cooling part while the first electronic part is in direct contact with the cooling part.
In accordance with another preferred embodiment of the present invention, there is provided a receiver including: a thermally insulated vessel; a cold head disposed inside the thermally insulated vessel; a superconducting filter mounted on the cold head; a low noise amplifier disposed inside the thermally insulated vessel, wherein the low noise amplifier is spaced apart from the cold head and electrically connected to the superconducting filter; and a radiation plate attached to the low noise amplifier.
REFERENCES:
patent: 5409547 (1995-04-01), Watanabe et al.
patent: 5603220 (1997-02-01), Seaman
patent: 5704212 (1998-01-01), Erler et al.
patent: 6112527 (2000-09-01), Steinmeyer et al.
patent: 6156970 (2000-12-01), Harting et al.
patent: 6226994 (2001-05-01), Yamada et al.
patent: 6298670 (2001-10-01), Pundak
patent: 6366461 (2
Kagaya Noriyuki
Okubo Yoichi
Suto Masaki
Takahashi Hideaki
Uchida Takashi
Bacon & Thomas PLLC
Doerrler William C.
Hitachi Kokusai Electric Inc.
Zec Filip
LandOfFree
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