JPH0685349A - Laser oscillator - Google Patents

Abstract

PURPOSE:To avoid the cracking in an insulating plate due to the differential pressure between inside and outside of a discharge tube. CONSTITUTION:A reinforcement member 10 is fixed on the outer surface of an insulating plate 7 to reinforce the same furthermore, engagement protrusions 10a projecting in the long direction are formed on both ends of this reinforcement member 10. On the other hand, both engagement protrusions 10a are supported from inside and outside by the supporting means 16 provided on a discharge tube 2. Through these procedures, the differential pressure between inside and outside of the discharge tube 2 even if it is applied on the insulating plate 7 can be relieved by the supporting means 16 through the intermediary of the reinforcement member 10. Accordingly, the deflection of the insulating plate 7 can be suppressed for preventing the inner stress of the insulating plate 7 from concentrating on the parts close to both ends of the insulating plate 7 thereby enabling the cracking in that parts to be avoided.

Description

Detailed Description of the Invention

FIELD OF THE INVENTION This invention relates to improvements in laser oscillators.

2. Description of the Related Art Conventionally, as a laser oscillator, a discharge tube having an opening formed along the longitudinal direction, an insulating plate for closing the opening of the discharge tube, and a discharge tube attached to the inner surface of the insulating plate are provided. An electrode housed inside and a reinforcing member fixed to the outer surface of the insulating plate along the longitudinal direction to reinforce the insulating plate are provided, and a laser beam is excited in a state in which a laser gas is sealed inside the discharge tube. Those configured as are known. In such a conventional laser oscillator,
First, after the atmosphere is discharged from the sealed discharge tube and the inside of the discharge tube is evacuated, a laser gas having a pressure higher than the atmosphere is supplied into the discharge tube to seal the discharge tube and a high voltage is applied to the electrodes in that state. Then, the laser beam is excited. When the laser gas in the discharge tube is deteriorated by repeatedly exciting the laser beam, the laser gas in the discharge tube is replaced with fresh laser gas in the above-described manner each time. In such a conventional device, the insulating plate is urged inward of the discharge tube by the atmospheric pressure every time the gas in the discharge tube is exchanged, and then continuously by the pressure of the laser gas toward the outside of the discharge tube. It will be in a state of being urged by. Then, conventionally, in order to reinforce the bending of the insulating plate when the differential pressure acts on the insulating plate as described above, the above-mentioned reinforcing member is fixed to the outer surface of the insulating plate.

However, in the above-mentioned conventional insulating plate, only the both ends in the longitudinal direction are directly connected to the positions of the openings of the discharge tube, and therefore, the difference acting on the insulating plate is caused. All pressure results in the insulation plate itself. As a result, the insulating plate bends, and internal stress concentrates on both ends of the insulating plate where the reinforcing member is not superposed. Therefore, there is a drawback that cracks occur at both ends of the insulating plate during repeated replacement of the laser gas in the discharge tube, and gas leakage occurs from those parts.

In view of the above-mentioned circumstances, the present invention provides a discharge tube having an opening formed along the longitudinal direction,
An insulating plate for closing the opening of the discharge tube, an electrode attached to the inner surface of the insulating plate and housed inside the discharge tube,
A laser oscillator comprising a reinforcing member fixed to the outer surface of the insulating plate along the longitudinal direction to reinforce the insulating plate, and configured to excite a laser beam in a state in which a laser gas is sealed inside the discharge tube. An engaging protrusion protruding in the longitudinal direction is formed at each end of the reinforcing member in the longitudinal direction, and the engaging protrusion is provided on the discharge tube from both sides in a direction orthogonal to the longitudinal direction of the discharge tube. The supporting means for supporting is provided.

According to this structure, even if the pressure difference acts on the insulating plate due to the exchange of the laser gas in the discharge tube, the pressure difference is received by the support means through both the engaging projections of the reinforcing member. You can As a result, it is possible to prevent concentration of internal stress due to bending at both ends of the insulating plate, and it is possible to prevent cracks from occurring at those parts. Therefore, it is possible to favorably prevent the laser gas from leaking due to the cracks in the insulating plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 3 is a cross-sectional view of a lateral pumping laser oscillator 1 for pumping an excimer laser.
The discharge tube 2 has a substantially cylindrical shape in which a laser gas is sealed. The discharge tube 2 is horizontally fixed on a frame 3 and accommodates a pair of main electrodes 4 and its accessories inside. The discharge tube 2 is filled with a laser gas whose pressure is about twice the atmospheric pressure from a laser gas supply source (not shown), and a high voltage is applied to the main electrode 4 with the laser gas filled therein. To excite the laser beam. When the laser gas is sealed in the discharge tube 2, the atmosphere in the discharge tube 2 is first evacuated to a vacuum, and then the laser gas is supplied into the discharge tube 2 for sealing. In addition, when the laser gas sealed in the discharge tube 2 deteriorates due to repeated excitation of the laser beam, the deteriorated gas is discharged from the discharge tube 2 each time, and fresh laser gas is discharged in the above-described manner. Is enclosed in the discharge tube 2. Also, the discharge tube 2
Inside, a fan 5 for circulating the gas in the discharge tube 2 is provided and a heat exchanger 6 is housed therein.
Thus, the main electrode 4 and its accessories are cooled. Further, the discharge tube 2 has a rectangular opening 2a formed over a predetermined range in the longitudinal direction thereof, and the opening 2a is closed by a rectangular insulating plate 7. A frame-shaped connecting member 8 forming a part of the discharge tube 2 is overlapped over the edge of the insulating plate 7 and the edge of the opening 2a to integrally connect the both edges. Insulation plate 7
A seal member 9 surrounding the opening 2a is attached to the contact surface of the connecting member 8 that overlaps with the edge of the opening 2a so that the opening 2a is completely sealed. The main electrode 4 and its accessory parts are attached to the inner surface of the insulating plate 7 in this state, while the outer surface of the insulating plate 7 has a plate-shaped reinforcing member 1 along its longitudinal direction.
0 is fixed, and the bending of the insulating plate 7 is reinforced by this. The reinforcing member 10 is made of iron plated with nickel, silver or the like, and therefore also serves as a conductor. Preliminary discharge capacitors 13 for preliminarily ionizing the laser gas between the main electrodes 4 are attached to the upper and lower surfaces of the reinforcing member 10, and the main electrodes 4 are provided on the frame 3 at the outer position adjacent to the preliminary discharge capacitors 13. A main discharge capacitor 14 for discharging is arranged. Further, a fan 15 for cooling the main discharge capacitor 14 and the preliminary discharge capacitor 13 is attached on the frame 3 adjacent to the main discharge capacitor 14. Therefore, in this embodiment, by improving the reinforcing member 10 and the connecting member 8, the pressure difference acting on the insulating plate 7 is received by the discharge tube 2 via the reinforcing member 10. That is, as shown in FIGS. 1 and 2, the engaging projections 10 are provided at both longitudinal end portions of the reinforcing member 10 so as to project in the longitudinal direction.
a is formed, and each of the engaging projections 10a is supported by the supporting means 16 formed on the connecting member 8 from both sides in the direction orthogonal to the longitudinal direction. Support means 1
6 is constituted by an L-shaped bracket 17 fixed to the central position of both sides of the connecting member 8 in the vertical direction, and an end surface of the connecting member 8 facing the free end 17a of the bracket 17, which are separated from each other. The engaging protrusions 10 are provided in the gap.
a is located. Then, between the outer side surface of the engagement protrusion 10a and the free end 17a of the bracket 17, and
Ceramic spacers 18 are interposed between the inner side surface of the engaging projection 10a and the end surface of the connecting member 8. In that state, a fastening bolt 19 is screwed through from the outside to the free end 17a of the bracket 17, and both spacers 18 and the engaging projections 10a are pressed from both sides by the tip of the fastening bolt 19 and the end face of the connecting member 8. It is sandwiched. As described above, in this embodiment, by supporting the engaging projections 10a of the reinforcing member 10 from both inside and outside by the supporting means 16, when the differential pressure acts on the insulating plate 7 from both inside and outside, the differential pressure is applied. Can be received by the supporting means 16 via the engaging projection 10a of the reinforcing member 10. Further, a pair of supporting members 20 are fixed to the central portion in the longitudinal direction of the reinforcing member 10 at predetermined intervals over both sides in the horizontal direction of the connecting member 8 (see FIG. 3). A spacer 18 made of ceramics similar to that described above is also interposed between them to support the same. Therefore, in this embodiment, the reinforcing member 1
Both ends (engaging protrusion 10a) of 0 and two places of the central portion are supported by the supporting means 16 and the supporting member 20. According to the configuration described above, the discharge tube 2
When a differential pressure acts on the insulating plate 7 from the inside and outside when exchanging the laser gas therein, the differential pressure can be received by the supporting means 16 and the supporting member 20. More specifically, when exchanging the laser gas, first, the deteriorated gas in the discharge tube 2 is discharged to make the inside of the discharge tube 2 into a vacuum. At that time, the vacuum and the atmospheric pressure are applied to the insulating plate 7. The differential pressure acts to urge the insulating plate 7 inward. However, in that case, the engaging protrusion 10 of the reinforcing member 10
The end surface on the inner side of a is supported by the connecting member 8 serving as the supporting means 16. Therefore, it is possible to prevent the insulating plate 7 from bending toward the inner side due to the differential pressure. Next, after this, if a laser gas is enclosed in the discharge tube 2 that has been evacuated,
Since the pressure of this laser gas is about twice the atmospheric pressure,
The insulating plate 7 is urged outward by the pressure difference between them. However, at this time, the outer end surface of the engaging projection 10a of the reinforcing member 10 is supported by the bracket 17 as the supporting means 16, and at the same time, the central portion of the reinforcing member 10 is supported by both supporting members 20. .
Therefore, it is possible to prevent the insulating plate 7 from bending outward due to the differential pressure. In this way, since the insulating plate 7 can be prevented from bending due to the pressure difference between the inside and outside of the discharge tube 2 due to the exchange of the laser gas, the both ends of the insulating plate 7 are connected to the connecting member 8. No, reinforcement member 1
Internal stress does not concentrate on both ends 7'of the insulating plate 7 where 0 is not superposed. Therefore, it is possible to prevent cracks from being formed in that portion, and therefore it is possible to prevent the laser gas in the discharge tube 2 from leaking to the outside due to the cracks in the insulating plate 7. As a result, the life of the insulating plate 7 can be extended and the life of the laser oscillator 1 can be extended. In contrast to the present embodiment as described above, conventionally, the engaging protrusion 10a is not formed on the reinforcing member 10, and the differential pressure inside and outside the discharge tube 2 is entirely received by the insulating plate 7, so that the insulating plate 7 is By bending inward and outward, stress was concentrated on both ends 7 ', and cracks were generated in that part, causing gas leakage.

As described above, according to the present invention, it is possible to satisfactorily prevent the laser gas from leaking due to cracks in the insulating plate.

[Brief description of drawings]

FIG. 1 is a plan view of FIG. 2 showing an embodiment of the present invention.

FIG. 2 is a sectional view of a main part taken along the line II-II of FIG.

FIG. 3 is a cross-sectional view of a laser oscillator showing an embodiment of the present invention.

[Explanation of symbols]

1 Laser oscillator 2 Discharge tube 4
Main electrode 7 Insulation plate 10 Reinforcing member 10
a engaging projection 16 support means

Front page continuation (72) Inventor Naoki Nishide 58 Soya Tamotocho Kou, Kanazawa, Ishikawa Prefecture Shibuya Industry Co., Ltd. (72) Inventor Fumihiko Miyamoto 58 Soybean Tamotocho Kanazawa, Ishikawa Prefecture Shibuya Industry Co., Ltd.

Claims (1)

[Claims] 1. A discharge tube having an opening formed in the longitudinal direction, an insulating plate for closing the opening of the discharge tube, and an electrode attached to the inner surface of the insulating plate and housed inside the discharge tube. A laser oscillator, which is fixed to the outer surface of the insulating plate along the longitudinal direction and reinforces the insulating plate, and is configured to excite a laser beam in a state in which a laser gas is sealed inside the discharge tube. In each of the reinforcing members, engaging protrusions projecting in the longitudinal direction are formed at both ends in the longitudinal direction of the reinforcing member, and the engaging protrusions are formed on the discharge tube on both sides in a direction orthogonal to the longitudinal direction of the discharge tube. A laser oscillator comprising support means for supporting the laser oscillator.