Coherent light generators – Particular pumping means – Electrical
Reexamination Certificate
2000-08-28
2004-08-03
Wong, Don (Department: 2828)
Coherent light generators
Particular pumping means
Electrical
C372S057000, C372S059000
Reexamination Certificate
active
06771685
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a discharging laser apparatus, and more particular to a discharge electrodes connecting structure in a laser apparatus and a laser apparatus provided with the discharge electrodes.
BACKGROUND OF THE INVENTION
Conventionally, there has been known a discharge exciting laser apparatus which generates a discharge between discharge electrodes so as to excite a laser medium, thereby oscillating a laser beam, and the discharge exciting laser apparatus is, for example described in Unexamined Japanese Patent Publication No. 1-268078.
FIG. 6
shows a structure of an excimer laser apparatus disclosed in the publication, and
FIG. 7
shows a discharge electrode structure of the excimer laser apparatus disclosed in the publication.
In
FIGS. 6 and 7
, an excimer laser apparatus
101
is provided with a laser chamber
102
for sealing a laser medium such as a laser gas or the like. A pair of discharge electrodes
105
A and
105
B constituted by an anode
105
A and a cathode
105
B are arranged in an inner portion of the laser chamber
102
in an opposing manner. The anode
105
A is fixed to a conductive anode base
106
and the cathode
105
B is fixed to an insulative cathode base
108
, respectively. A discharge is generated between the anode
105
A and the cathode
105
B so as to excite a laser gas shown by an arrow G flowing between the discharge electrodes
105
A and
105
B, thereby oscillating a laser beam.
Auxiliary ionization electrodes
118
and
118
are respectively arranged in both sides of the discharge electrodes
105
A and
105
B in an opposing manner, to which a high voltage current is supplied from a high voltage power source via an auxiliary ionization circuit and a current introduction terminal (not shown), thereby performing an auxiliary ionization.
The anode base
106
and the cathode base
108
are supported to keep a predetermined interval by a supporting post
110
. Further, the anode base
106
and the laser chamber
102
are electrically connected by a plurality of return plates
109
arranged in a longitudinal direction of the discharge electrode to keep a predetermined interval. In this case, a connecting portion between a return plate
109
and the laser chamber is not clearly illustrated in the publication mentioned above. The return plate
109
is constituted by a conductive sheet member and is arranged in parallel to the gas flow G so as not to prevent the gas flow of the laser gas between the discharge electrodes
105
A and
105
B and so that a thin portion
109
A is directed to an upstream side and a downstream side of the gas flow G with respect to the gas flow.
Further, a once through fan
114
for feeding the laser gas to a portion between the discharge electrodes
105
A and
105
B, and a heat exchanger
103
for cooling the laser gas heated between the discharge electrodes
105
A and
105
B due to the discharge are respectively arranged at predetermined positions within the laser chamber
102
.
However, the conventional art disclosed in Unexamined Japanese Patent Publication No. 1-268078 has the following problems.
That is, in the conventional art, there is a description that the return plate
109
is formed in a thin sheet shape, a resistance of the laser gas is reduced and a rectifying effect for rectifying the gas flow G of the laser gas is expected as a thickness of the return plate
109
becomes thinner. However, it is known that when making the return plate
109
too thin, the return plate
109
vibrates due to the gas flow G so as to prevent the gas flow G and reduce a flow speed. Accordingly, the discharge becomes unstable and a power of the laser beam changes. Further, when making the thickness of the return plate
109
too thin, the resistance of the current flowing through the return plate
109
is increased, so that the discharge is not properly performed.
SUMMARY OF THE INVENTION
The present invention is made by solving the problems in the technique mentioned above, and an object of the present invention is to provide a discharge electrodes connecting structure for a laser apparatus in which a thickness of the return plate is set to be within an optimum range, and a laser apparatus employing the same.
In order to achieve the object mentioned above, in accordance with the present invention, there is provided a discharge electrodes connecting structure for a laser apparatus comprising:
a pair of anode and cathode provided within a laser chamber for sealing a laser gas in an opposing manner, generating a discharge so as to excite a laser gas flowing therebetween and oscillating a laser beam;
a conductive anode base holding the anode;
an insulative cathode base holding the cathode; and
a return plate electrically connecting the anode base to the laser chamber so as to supply a current to the anode and having a thickness of equal to or more than 100 &mgr;m and equal to or less than 500 &mgr;m.
Further, in accordance with the present invention, there is provided a laser apparatus comprising:
a laser chamber sealing a laser gas;
discharge electrodes constituted by a pair of anode and cathode provided within the laser chamber in an opposing manner, generating a discharge so as to excite a laser gas flowing therebetween and oscillating a laser beam;
a conductive anode base holding the anode;
an insulative cathode base holding the cathode; and
a return plate electrically connecting the anode base to the laser chamber so as to supply a current to the anode
wherein a thickness of the return plate is set to be equal to or more than 100 &mgr;m and equal to or less than 500 &mgr;m, and the return plate is arranged substantially in parallel to a gas flow of the laser gas flowing between the discharge electrodes.
In accordance with the structure mentioned above, since the thickness of the return plate is made thin to a level equal to or less than 500 &mgr;m and the return plate is arranged in parallel to the gas flow, the return plate hardly disturb the gas flow of the laser gas flowing between the anode and the cathode. Further, since the thickness of the return plate is set to be equal to or more than 100 &mgr;m, the return plate does not vibrate due to the gas flow. Further, since the thickness of the return plate is made thicker than an entering depth of a high frequency current flowing on a surface of the return plate at a time of discharging, a resistance of the current is not increased and the discharge can be properly performed. Accordingly, the discharge becomes stable and a power of the laser beam becomes stable.
REFERENCES:
patent: 4051855 (1977-10-01), Schneiderman
patent: 5771258 (1998-06-01), Morton et al.
patent: 6128323 (2000-10-01), Myers et al.
patent: 6608853 (2003-08-01), Yoshioka et al.
patent: 6628693 (2003-09-01), Ishihara et al.
patent: 6639929 (2003-10-01), Mizoguchi et al.
patent: 1-268078 (1989-10-01), None
Ishihara Takanobu
Kawasuji Yasufumi
Matsunaga Takashi
Yabu Takayuki
Armstrong Kratz Quintos Hanson & Brooks, LLP
Jackon Cornelius H.
Komatsu Ltd.
LandOfFree
Discharge electrodes connecting structure for laser... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Discharge electrodes connecting structure for laser..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Discharge electrodes connecting structure for laser... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3285686