JPS63100786A - Gas laser device - Google Patents

Abstract

PURPOSE:To prevent the lowering of an output from a laser and the shortening of the life of a gas circulating in a laser tube by mounting a turbulent flow plate into the laser tube and agitating the gas while forcibly flowing the gas through a heat exchanger. CONSTITUTION:A laser medium gas is passed through a discharge section 1 generated between a pair of electrodes disposed into a laser tube 4, thus exciting the gas, then generating laser oscillation. The fatigued and deteriorated gas after discharge is diverted when it passes through turbulent flow plates 5. The laser medium gas is separated into three directions, and one part flows along the wall surface of the laser tube, the other one part in the direction of heat exchangers 2 and the remainder toward approximately the central section of the laser tube. The turbulent flow plates 5 have length sufficient for covering a discharge region by a pair of discharge electrodes fitted in the longitudinal direction of the laser tube 4, and are fixed onto the inner wall section of the laser tube 4 immediately after the gas passes through the discharge section 1 regarding a gas flow. Accordingly, the lowering of an output from a laser and the shortening of the life of the gas can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention improves the flow of laser medium gas in a laser tube,
This invention relates to a gas laser device that increases the laser output during continuous oscillation and extends the life of the gas.

(Prior Art) As a conventional gas laser device, there is one shown in FIG. 4, for example. In this gas laser device, a laser medium gas is caused to pass through a discharge section 1 generated between at least a pair of electrodes arranged in a laser tube 4, thereby exciting the gas and causing laser oscillation.

After the discharge, the fatigued and deteriorated gas passes through the heat exchanger 2, is regenerated, and is sent to the discharge section 1 again by the circulation fan 3.

(Problems to be Solved by the Invention) When performing high repetition oscillation in a conventional gas laser device, the gas flow velocity in the laser tube is 10 m/sec or more. As shown in FIG. 5(a), the heat exchanger 2 is connected to the laser tube 4.
If the gas is installed in the center of the laser tube, the gas circulated at high speed will circulate along the wall of the laser tube, be cooled by the heat exchanger 2, and the gas with increased viscosity will be concentrated in the center of the laser tube. After discharge, only gas that has become high in temperature and has low viscosity circulates, making it difficult to mix with the gas present at the center of the laser tube.

Furthermore, as shown in FIG. 5(b), if the heat exchanger 2 is installed very close to the wall surface of the laser tube 4, viscous gas may be cooled between or near the heat exchanger and the wall surface. The high-temperature gas concentrates, and after discharge, the high-temperature, low-viscosity gas circulates over the area, making it difficult for the gases to mix.

As described above, in the conventional gas laser device, the low viscosity gas that has become high temperature due to discharge is sent to the discharge section 1 again, resulting in a decrease in laser output and gas life.

(Means and operations for solving TLi1 problem) In order to solve the above problems, in the present invention, a turbulence plate is provided in the laser tube to stir the gas circulating in the laser tube, and
It is forced to flow through the heat exchanger.

According to the present invention, the gas exhausted by the discharge and the cooled and regenerated gas are mixed and stirred.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of a gas laser device according to the present invention.

This gas laser device excites the laser medium gas and causes laser oscillation by passing the laser medium gas through a discharge section 1 generated between at least a pair of electrodes disposed in a laser tube 4.

After discharge, the fatigued and deteriorated gas is divided when passing through the turbulence plate 5.

In the embodiment shown in FIG. 1, the laser medium gas is divided into three directions, one part along the laser tube wall surface, the other part flowing along the
In the direction of heat exchange 52, the residue flows toward approximately the center of the laser tube.

Note that the white arrows in the drawings are symbols used to indicate gas flows.

FIG. 2 shows a detailed view of the turbulence plate 5. The turbulent flow plate 5 is made of a Teflon plate or the like, and is used to adjust the bending of the blades of the turbulent flow plate 5 by 5° in accordance with the arrangement of various devices installed in the laser tube.

The above-mentioned turbulent flow Fi5 has a length sufficient to cover the discharge region formed by at least a pair of discharge electrodes provided in the longitudinal direction of the laser tube 4.

The turbulent flow plate 5 is fixed to the inner wall of the laser tube 4 immediately after the gas flow passes through the discharge section 1 by an arbitrary means such as a screw.

FIG. 3 is a diagram showing details of another embodiment of the turbulence plate 5. In FIG.

In the case of the turbulent flow plate 5, there are two divided directions. If such a turbulent flow plate 5 is used, a part of the fatigued and deteriorated gas flowing out from the discharge section will be forced to flow into the heat exchanger, thereby eliminating the stagnation of low-temperature gas near the heat exchanger. Cooled gas can be sent to the circulation path.

Further, other gases flow as they are along the wall surface inside the laser tube, maintaining a smooth gas flow.

(Effects of the Invention) According to the present invention, (1) Gas fatigued and degraded by discharge and cooled and regenerated gas are mixed and stirred without impairing smooth gas circulation within the laser tube.

(2) According to (1) above, it is possible to suppress a decrease in laser output and gas life.

(3) To provide a gas laser device having excellent effects such as an increase in output of about 40% when an ArF (193 nm) output test was conducted using the same device and under the same conditions by using the turbulence plate 5. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a sectional view conceptually showing an embodiment of a gas laser device according to the present invention, FIGS. 2 and 3 are perspective views showing a turbulence plate in the embodiment according to the present invention, and FIG. 5 is a cross-sectional view conceptually showing a conventional gas laser device, and FIG. 5 is a diagram conceptually showing gas stagnation in the conventional gas laser device.

Claims (1)

[Claims] A gas laser device in which a medium gas is circulated by a circulation fan, characterized in that a turbulence plate is provided on the inner wall of the laser tube immediately after the medium gas flow passes through a discharge section.