Coherent light generators – Particular pumping means – Electrical
Reexamination Certificate
2000-09-11
2002-12-03
Ip, Paul (Department: 2828)
Coherent light generators
Particular pumping means
Electrical
C372S057000
Reexamination Certificate
active
06490310
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a laser device, and more particularly to connection structure of discharge electrodes in a laser device and a laser device including the discharge electrodes.
BACKGROUND ART
A laser device which discharges electricity between discharge electrodes to excite a laser medium, thereby oscillating a laser beam has been hitherto known and is shown, for example, in Japanese Patent Laid-open No. 1-268078 Official Gazette.
FIG. 10
shows the structure of an excimer laser device disclosed in the aforesaid Official Gazette, and
FIG. 11
shows the structure of discharge electrodes in the excimer laser device disclosed in the aforesaid Official Gazette.
In FIG.
10
and
FIG. 11
, an excimer laser device
101
includes a laser chamber
102
sealing in a laser medium such as laser gases. Inside the laser chamber
102
, a pair of discharge electrodes
105
A and
105
B composed of an anode
105
A and a cathode
105
B are disposed facing each other. The anode
105
A is fixed to a conductive anode base
106
, and the cathode
105
B is fixed to an insulating cathode base
108
.
A pair of preionization electrodes
118
and
118
are disposed facing each other on both sides of the discharge electrodes
105
A and
105
B, and a high-voltage current is supplied from a high voltage power supply though a preionization circuit and a current introducing terminal which are not illustrated, thereby performing preionization.
Inside the laser chamber
102
, a cross flow fan
114
for sending laser gases into a space between the discharge electrodes
105
A and
105
B and a heat exchanger
103
for cooling the laser gases heated by electric discharge are disposed at predetermined positions. Electricity is discharged between the anode
105
A and the cathode
105
B to excite laser gases, shown by the arrows G, flowing through the space between the anode
105
A and the cathode
105
B, thereby oscillating a laser beam.
The anode base
106
and the cathode base
108
are supported by support posts
110
with a predetermined space between them. The anode base
106
and the laser chamber
102
are electrically connected with a plurality of return plates
109
arranged at predetermined intervals in the longitudinal direction of the discharge electrodes
105
A and
105
B. It should be mentioned that connection points of the return plates
109
and the laser chamber
102
are not clearly illustrated in the aforesaid Official Gazette. Each of the return plates
109
is made of a conductive plate-shaped member, and disposed parallel to the gas flow G so that a portion
109
A with a thin plate thickness faces to the upper reaches and the lower reaches of the gas flow G with respect to the gas flow.
The prior art disclosed in the aforesaid Japanese Patent Laid-open No. 1-268078 Official Gazette, however, has the following problems.
Namely, in the prior art, in order to smoothly supply an electric current to the whole area in the longitudinal direction of the anode
105
A to suitably discharge electricity, the plurality of return plates
109
are provided in the whole area in the longitudinal direction. When the excimer laser device
101
is assembled, the plurality of return plates
109
need to be attached one by one so as to connect the anode base
106
and the laser chamber
102
, which requires a lot of trouble over assembling.
Furthermore, the discharge electrodes
105
A and
105
B become worn-out as the result of electric discharge, and hence they need to be replaced regularly. Every time the discharge electrodes
105
A and
105
B are replaced as above, the plurality of return plates
109
need to be attached/detached, which takes a lot of time and labor.
SUMMARY OF THE INVENTION
The present invention is made to solve the problems in the aforesaid art, and its object is to provide a discharge electrode for a laser device allowing return plates to be easily attached/detached and a laser device with the discharge electrode.
To attain the aforesaid object, a discharge electrode for a laser device according to the present invention has structure in which a pair of an anode and a cathode, provided facing each other inside a laser chamber sealing in laser gases, for discharging electricity to excite the laser gases flowing through a space between them, thereby oscillating a laser beam, a conductive anode base for holding the anode, an insulating cathode base for holding the cathode, and a plurality of return plates for electrically connecting the anode base and the laser chamber and supplying an electric current to the anode are provided, and in which upper portions and lower portions of the return plates are connected respectively with an upper fixed plate and a lower fixed plate.
Furthermore, a laser device according to the present invention has structure in which a pair of an anode and a cathode, provided facing each other inside a laser chamber sealing in laser gases, for discharging electricity to excite the laser gases flowing through a space between them, thereby oscillating a laser beam, a conductive anode base for holding the anode, an insulating cathode base for holding the cathode, and a plurality of return plates for electrically connecting the anode base and the laser chamber and supplying an electric current to the anode are provided, and in which upper portions and lower portions of the return plates are connected respectively with an upper fixed plate and a lower fixed plate.
According to the aforesaid structure, the plurality of return plates are integrated at the upper and lower portions thereof to be formed into a unit. Thereby, when the return plates are attached/detached, each unit of return plates may be attached/detached, which saves a lot of time and labor compared with a case where a plurality of return plates are attached.
Moreover, the discharge electrode for the laser device and the laser device may each have structure in which the return plates are disposed almost parallel to gas flow of the laser gases flowing through the space between the discharge electrodes.
According to the aforesaid structure, the return plates rectify the gas flow of the laser gases, thereby making the flow of the laser gases smooth and increasing flow velocity. As a result, electric discharge is stabilized, and the power of the laser beam is raised.
REFERENCES:
patent: 5247534 (1993-09-01), Muller-Horsche
patent: 5923639 (1999-07-01), Ohmi et al.
patent: 5978405 (1999-11-01), Juhasz et al.
patent: 6052402 (2000-04-01), Murray et al.
patent: 1-268078 (1989-10-01), None
Ishihara Takanobu
Kawasuji Yasufumi
Matsunaga Takashi
Yabu Takayuki
Armstrong, Westerman & Westerman
Ip Paul
Komatsu Ltd.
Monbleau Davienne
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