Coherent light generators – Particular active media – Gas
Reexamination Certificate
1998-11-23
2001-02-13
Healy, Brian (Department: 2874)
Coherent light generators
Particular active media
Gas
C372S038060, C372S058000, C372S055000, C372S087000
Reexamination Certificate
active
06188709
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to laser systems and, more specifically, to a support bar for supporting an electrode member of the laser system.
BACKGROUND OF THE INVENTION
Pulsed laser systems, such as excimer lasers, are well known.
FIG. 1
is an end cross sectional view of a laser chamber, generally illustrated as
10
, used in a conventional pulsed laser system. The laser chamber
10
comprises a pair of electrode members
12
, which include a cathode
14
and an anode
16
. The area between the cathode
14
and the anode
16
is referred to as an electrical discharge area
18
. A support bar member
20
supports the anode
16
. A heat exchanger
22
, and a blower assembly
24
are also disposed within the laser chamber
10
. As is well known by those skilled in the art, the pulsed laser system produces energy pulses from a gas mixture in the electrical discharge area
18
. The mixture of gas, which typically includes krypton and fluorine, is maintained at a high pressure (e.g., 3 atm.). The electrode members
12
ionize the gas mixture to produce a high energy discharge.
The blower assembly
24
plays the important role of circulating the gases in the laser chamber
10
of the pulsed laser system. The circulation of the gases has many purposes, including maintaining the temperature of the gases at the most efficient level of reaction, maximizing the life cycle of the gases, and facilitating the overall operation of the pulsed laser system.
The blower assembly
24
comprises a plurality of blades or vanes
26
which are driven in a clockwise direction, as indicated by arrow
28
, for circulating the gases about the laser chamber
10
. The directional flow of the gases, as indicated by arrows
30
, is through the electrical discharge area
18
, with a clockwise circulation about the heat exchanger
22
, and through the blower assembly
24
. The gases pass between the blades
26
of the blower assembly
24
, as illustrated by the arrow
30
.
The support bar member
20
, configured to support the anode
16
, includes a cut-off point, as indicated by numeral
21
. The cut-off point
21
is a general region on the support bar member
20
, located adjacent to the blower assembly
24
, which defines the inlet side and the outlet side of the blower assembly
24
.
Each time one of the blades
26
passes the cut-off point
21
, the support bar member
20
applies an aerodynamic load to the blower assembly
24
. The aerodynamic load agitates the blower assembly
24
, causing the blower assembly
24
to vibrate. As the rotational speed of the blades
26
increases, so does the aerodynamic load, and, thus, the vibration of the blower assembly
24
. The effect of the rotational speed of the blades
26
, i.e., the blower speed, on the vibration of the blower assembly
24
is illustrated in FIG.
2
. Curve A illustrates the vibration response in the range of 2500 to 4000 vibrations per minute corresponding to blower speeds of 2500 RPM to 4000 RPM. Curve B illustrates the vibrational response associated with twice the rotational speed, and curve C illustrates the vibrational response associated with 23 times the rotational speed (i.e., 23 vanes or blades
26
).
Furthermore, the vibration of the blower assembly
24
is highly detrimental to our application due to the nature of beam stability as it travels through. In the past any reduction of rotating mass vibration was necessarily associated with blower speed reduction. Blower speed reduction results in gas flow reduction. Gas flow reduction disabled the function of the laser. The vibration reduces the output efficiency of the blower assembly
24
by about 10%. The vibration also increases the noise produced by the blower assembly
24
. Moreover, the vibration causes deterioration and failure of the mechanical components of the blower assembly
24
, such as the blower assembly's
24
bearing members, driver shaft, and other moving components. As a result, it would be advantageous to reduce the vibration of the blower assembly
24
.
SUMMARY
An improved laser chamber is disclosed which does not suffer from the above-described drawbacks. The laser chamber has a pair of electrode members—an anode and a cathode—defining an electrical discharge area for producing a high energy discharge. The laser chamber includes a blower assembly for the proper circulation and the efficient flow of gases during the operation of the electrode members.
The laser chamber further includes a support bar member for supporting one of the electrode members, e.g., the anode. The support bar member comprises an aerodynamic nose configured to reduce an aerodynamic load that is applied against the blower assembly by the support bar member when the blower assembly is rotatably driven. As a result, the blower assembly does not vibrate significantly.
REFERENCES:
patent: 4959840 (1990-09-01), Akins et al.
patent: 5023884 (1991-06-01), Akins et al.
patent: 5029177 (1991-07-01), Akins et al.
patent: 5033055 (1991-07-01), Akins et al.
patent: 5048041 (1991-09-01), Akins et al.
patent: 5313481 (1994-05-01), Cook et al.
patent: 5315611 (1994-05-01), Ball et al.
patent: 5337330 (1994-08-01), Larson
patent: 5377215 (1994-12-01), Das et al.
patent: 5448580 (1995-09-01), Birx et al.
patent: 5719896 (1998-02-01), Watson
patent: 5771258 (1998-06-01), Morton et al.
patent: 5856991 (1999-01-01), Ershov
Cymer Inc.
Healy Brian
Ross, Esq. John R.
LandOfFree
Aerodynamic electrode support bar does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Aerodynamic electrode support bar, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aerodynamic electrode support bar will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2603791