JPH10163546A - Gas laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly improve the life time of a bearing in a compact structure by surely blocking dust from entering into a laser chamber. SOLUTION: A gas laser comprises a laser gas/contg. laser chamber 1, a fan 2 for circulating the laser gas in the chamber 1, a casing 5 for defining a space at the inner wall of the chamber 1 which a rotary shaft 3 of the circulating fan 2 pierces, and bearing housed in the casing 5 for pivoting the shaft 3 of the fan 2. It has means for introducing a pure laser gas into a space defined by the bearing and wall of the casing 5, including its holes and an axial flow fan 8 for sucking the pure laser gas through a gap between the rotary shaft 3 and inner wall of the hole of the casing 5. The fan 8 disposed between the circulating fan 2 at the rotary shaft 3 of the fan 2 and the wall of the casing 5, including the hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device such as an excimer laser and, more particularly, to a bearing portion provided outside a laser chamber for supporting a laser gas circulation fan for circulating a laser gas in the laser chamber. To prevent dust from entering the laser chamber from entering the laser chamber.

[0002]

2. Description of the Related Art In a gas laser device such as an excimer laser, a blower (fan) is built in the laser chamber to circulate a laser gas sealed in the laser chamber. In order to rotate the fan, a motor is required, but since the motor is corroded by a laser gas (such as a halogen gas), the motor is installed outside the laser chamber. Therefore, it is necessary to connect the motor and the fan with the rotating shaft, and to provide bearings for supporting the rotating shaft on both side surfaces of the laser chamber.

[0003] Here, when evaporators or fine particles of a lubricant such as grease or oil used in the bearing portion enter the laser chamber, they become impurities and hinder laser oscillation and shorten the life of the laser gas. Therefore, it is necessary to reliably shut off the bearing from the laser gas. For this reason, conventionally, a shaft seal made of a magnetic fluid or the like has been used for the bearing portion. However, the shaft seal structure using only the magnetic fluid has a problem that dust generated by electric discharge enters the shaft seal from a gap, thereby lowering the sealing performance of the shaft seal and significantly shortening the life of the shaft seal and the bearing.

Therefore, in Japanese Patent Application Laid-Open No. 3-200388, a curtain is formed by a clean laser gas so as to close the gap with a gas reservoir. FIG.

In FIG. 6, a rotating shaft 100 is connected at its outer end to a motor and at its inner end to a laser gas circulation fan. The shaft seal 101 has a body 103 of a housing 102 and a hole 1 formed in a pressure vessel 104.
05, and the flange 106 is abutted and fixed to the outer surface of the pressure vessel 104. Also, the rotating shaft 100
Is a hole 107 of the housing 102, a bearing 108,
Pole piece 109, magnet 110, pole piece 11
1. Bearing 112 and hole 11 in housing 102
3 and each bearing 108, 112
It is fixed to the inner race.

According to the shaft seal 101, the magnet 110
The magnetic fluid 115 is collected in the gap between the rotating shaft 100 and the projections 114 formed on the pole pieces 109 and 111 on the pole pieces 109 and 111 by the magnetic field created by the magnetic field 115 to achieve sealing. However, with this configuration, dust generated by the discharge enters the housing 102 through the gap between the holes 113.

Therefore, a gas reservoir 116 is provided so as to cover the hole 113, and a clean laser gas is supplied to the gas reservoir 116 via a supply pipe 117. According to this configuration, the gas reservoir 116 passes through the supply pipe 117.
Is temporarily held in the gas reservoir 116 and blows out from a gap 118 formed between the shaft 100 and the gas holder 116. Therefore, a curtain is formed along the outer periphery of the shaft 100 by the blown laser gas, and dust is prevented from entering the housing 102 through the gap 118.

[0008]

However, according to this conventional method, a clean laser gas curtain is formed on the outer periphery of the shaft 100 only by blowing a clean laser gas retained in the gas reservoir 116 from the narrow gap 118. Therefore, when a clean laser gas is blown into the pressure vessel through the gap 118, dust in the laser chamber may be entrained, and the dust may enter the gas reservoir 116 against the blown gas. The life of the parts and bearings does not increase much.

Further, in this conventional method, since the laser gas is supplied from outside the apparatus in order to supply the clean gas to the gas reservoir 116, there is a problem that the apparatus becomes large-scale.

The present invention has been made in view of such circumstances, and provides a gas laser device having a compact structure, reliably preventing dust from entering the inside of a laser chamber, and dramatically improving the life of a bearing. The purpose is to do.

[0011]

According to the present invention, a laser chamber in which a laser gas is sealed, a gas circulation fan for circulating the laser gas in the laser chamber, and a rotating shaft of the gas circulation fan are inserted through the laser chamber. In a gas laser device comprising: a casing defining a space in an inner wall portion of a laser chamber; and a bearing housed in the casing and supporting a rotation axis of the gas circulation fan, a hole of the bearing and the casing is provided. A laser gas introduction unit for introducing a clean laser gas into a space formed between the gas circulation fan and a wall of the rotation axis of the gas circulation fan. Between the inner peripheral surface of the hole of the casing and the rotating shaft. And an axial fan for sucking a clean laser gas introduced therebetween.

[0012]

According to the present invention, the dust exit side (outside the laser chamber) of the insertion hole of the rotation shaft of the gas circulation fan formed in the wall of the laser chamber, which is the passage of the dust entering the bearing from inside the laser chamber. ), A space for storing a clean laser gas is formed, and an axial fan is provided at the entrance of the dust (in the laser chamber). Then, the axial flow fan actively sucks the clean laser gas stored in the space into the laser chamber through the insertion hole, so that dust in the laser chamber enters the bearing through the insertion hole. To ensure that

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a view conceptually showing a main part of the present invention. A gas circulation fan (through-flow fan) 2 for circulating a laser gas is provided inside a laser chamber 1 in which a laser gas is sealed. Have been. The shaft 3 of the once-through fan 2 extends outside the laser chamber via an insertion hole 4 formed in the laser chamber 1. In the casing 5, a bearing for supporting the shaft 3 is accommodated.

A room 6 for storing a clean laser gas is defined between the casing 5 and the outer wall surface of the laser chamber 1, and the room 6 is supplied with a clean laser gas through a gas passage 7.

On the other hand, the cross-flow fan 2 on the shaft 3 of the cross-flow fan 2
An axial fan 8 is provided between the
(A blower for flowing gas in a direction along the rotation axis) is attached, and the axial flow fan 8 sucks a flow of sucking the clean laser gas stored in the room 6 into the laser chamber 1 through the gap of the insertion hole 4. generate. This reliably prevents dust generated in the laser chamber from entering the casing 5 in which the bearing is accommodated through the gap between the insertion holes.

A plurality of irregularities 9 (labyrinths) are formed on the inner peripheral surface of the insertion hole 4 of the laser chamber 1.
The reverse flow of the clean laser gas flowing from the room 6 into the laser chamber 1 is prevented. Further, the laser chamber 1 is formed with a cylindrical extending portion 10 extending so as to surround the axial fan 8 so that the distance t between the extending portion 10 and the axial fan 8 is reduced. Thus, the backflow of the clean laser gas described above is prevented.

FIG. 2 is a cross-sectional view showing the overall configuration of the gas laser apparatus according to the present invention. A laser gas is sealed in the laser chamber 1 and a predetermined voltage is applied between the discharge electrodes 11 to perform discharge. Generates a laser beam. The generated laser light is emitted out of the laser chamber 1 through the windows 12 and 13.

On the other hand, the laser gas in the laser chamber 1 is supplied by
Circulates inside. The cross-flow fan 2 is connected to a motor 14 via a rotating shaft 3 and is rotated by the motor 14.

The laser gas circulated in the laser chamber 1 is sent to a gas dust removing device (dust removing filter) 16 via a gas passage 15, where the dust is removed by the gas dust removing device 16. The clean laser gas after passing through the gas dust removal device 16 passes through a gas passage 17 formed in the wall of the laser chamber 1, and a part thereof passes through a labyrinth portion (laser light passage portion) 18 of a window. The gas is returned into the laser chamber 1 and the remainder is supplied to the above-mentioned room 6 via the gas passage 7.

FIG. 3 shows a detailed configuration in an elliptical frame P shown on the right of the laser chamber 1 in FIG.

In FIG. 3, the rotating shaft 3 of the once-through fan 2 is supported by bearings 20 and 22 housed in the casing 5. The casing 5 is fixed to the laser chamber 1 at the flange portion 21, and the interior of the casing 5 is separated from the motor 40 by an extended barrier portion 35.

A permanent magnet 43 is attached to a rotating shaft 41 of the motor 40 via a magnet support 42. On the other hand, a permanent magnet 44 is provided around the end of the rotating shaft 3 of the cross-flow fan 2 so as to face a permanent magnet 43 provided on the motor side. Is configured. That is, in this case, the rotational power of the motor 40 is transmitted to the rotating shaft 3 of the cross-flow fan 2 by the magnetic torque coupling 45, and the motor 40 side and the inside of the casing 5 are formed by the barrier 35. Completely isolated.

On the other hand, as described above, a room 6 for storing a clean laser gas is defined between the bearing 22 and the outer wall surface of the laser chamber 1, and the room 6 is provided with a clean laser gas through the gas passage 7. A laser gas is supplied. Also, in the laser chamber 1, the shaft 3 of the once-through fan 2
An axial fan 8 is attached, and the axial fan 8 generates a flow of sucking clean laser gas stored in the room 6 into the laser chamber 1 through the gap of the insertion hole 4. A plurality of irregularities 9 (labyrinths) are formed on the inner peripheral surface of the insertion hole 4 of the laser chamber 1 so as to prevent the backflow of the laser gas. Further, the laser chamber 1 is formed with a cylindrical extending portion 10 extending so as to surround the axial fan 8, so that the distance between the extending portion 10 and the axial fan 8 is reduced. In this case, the backflow of the laser gas is prevented.

FIGS. 4A and 4B show the structure of the axial fan 8, wherein FIG. 4A is a plan view, FIG. 4B is a side view, and FIG. The axial flow fan 8 functions to flow gas in a direction parallel to the axis 3 by a plurality of guide blades 30 having a predetermined angle α.

FIG. 5 shows a detailed configuration in an elliptical frame Q shown on the left of the laser chamber 1 in FIG.

The rotating shaft 3 of the once-through fan 2 is
It is supported by bearings 51 and 53 housed therein. The casing 50 is fixed to the laser chamber 1 at its flange 52.

On the other hand, as described above, a room 60 for storing a clean laser gas is defined between the bearing 53 and the outer wall surface of the laser chamber 1, and the clean laser gas is supplied to the room 60 through a gas passage 61. Supplied. Also, in the laser chamber 1, the shaft 3 of the once-through fan 2
An axial fan 62 is attached, and the axial fan 62 generates a flow for sucking the clean laser gas stored in the room 60 into the laser chamber 1 through the gap of the insertion hole 63. Further, a plurality of irregularities 64 (labyrinth) are formed on the inner peripheral surface of the insertion hole 63 of the laser chamber 1 so as to prevent the backflow of the laser gas. Further, the laser chamber 1 is formed with a cylindrical extending portion 65 extending so as to surround the axial fan 62, and the distance between the extending portion 65 and the axial fan 62 is reduced. In this case, the backflow of the laser gas is prevented.

As described above, according to this embodiment, the insertion holes 4 on both sides of the rotary shaft 3, which are passages for dust to enter from the inside of the laser chamber 1 to the casings 5 and 50 for bearings.
A room 6 and 60 for storing a clean laser gas are formed outside the laser chamber 63, and axial fans 8 and 62 are disposed on the entrance side of the dust, and the rooms 6 and 60 are stored by the axial fans 8 and 62. The dust in the laser chamber 1 enters the casings 5 and 50 through the insertion holes 4 and 63 by actively sucking the clean laser gas into the laser chamber 1 through the insertion holes 4 and 63. To ensure that they do Further, in this embodiment, after the laser gas circulated in the laser chamber 1 is passed through the dust removing device 16 in the laser chamber, it is guided to the rooms 6 and 60 in front of the insertion holes 4 and 63.
It is not necessary to separately provide a supply device for supplying a clean laser gas to the outside of the laser chamber, and the device configuration can be made compact.

[0030]

As described above, according to the present invention,
A space for storing a clean laser gas is formed on the bearing side of the insertion hole of the rotation shaft of the gas circulation fan formed on the wall of the laser chamber, and an axial fan is disposed inside the laser chamber of the insertion hole. The fan allows the clean laser gas stored in the space to be positively sucked into the laser chamber through the insertion hole, so that dust in the laser chamber enters the bearing through the insertion hole. As a result, the bearing life can be significantly extended.

Further, in the present invention, the laser gas circulated in the laser chamber is cleaned and removed in the laser chamber, and the purified gas is guided to the space in front of the insertion hole. There is no need to separately install a supply device for supplying, and the device configuration can be made compact.

[Brief description of the drawings]

FIG. 1 is a diagram conceptually showing a main part of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an overall configuration of a gas laser according to an embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of the embodiment of FIG. 2;

FIG. 4 is a diagram showing an example of an axial fan.

FIG. 5 is a partially enlarged sectional view of the embodiment of FIG. 2;

FIG. 6 is a diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laser chamber wall 2 ... Laser gas circulation fan (through-flow fan) 3 ... Rotating shaft 4, 63 ... Insertion hole 5, 50 ... Casing 6, 60 ... Gas chamber 7, 61 ... Gas passage 8, 62 ... Axial fan 9: unevenness (labyrinth) 10: extension

Claims (1)

[Claims] A laser chamber in which a laser gas is sealed; a gas circulation fan for circulating the laser gas in the laser chamber; a rotation shaft of the gas circulation fan is inserted through the laser chamber; A gas laser device, comprising: a casing defining the bearing; and a bearing housed in the casing and supporting the rotating shaft of the gas circulation fan. A laser gas introducing means for introducing a clean laser gas into a space formed in a space formed between the gas circulation fan and a wall surface including a hole of the casing on a rotation axis of the gas circulation fan. A clean laser introduced into the space through a gap between the inner peripheral surface of the hole of the casing and the rotating shaft. Gas laser apparatus being characterized in that comprising the axial-flow fan for sucking the gas.