JPH01218082A - Cross flow type laser device - Google Patents

Abstract

PURPOSE:To make the discharge tube of a crossflow laser device compact, by providing a gas induction pipe equipped with a gas injection port to the side of an electric discharge path. CONSTITUTION:A gas fed by a circulation pump 9 is introduced in the inside of an electric discharge tube 1 by way of a gas inlet 4 after passing through a piping path 8. A gas induction pipe 6 is connected to the gas inlet 4 and the gas fed to the gas inlet 4 is sprayed from a gas injection port 7 which is attached at the side face of the gas induction pipe 6 and then, the electric discharge tube 3 is cut off at once. In such a case, the gas running through the discharge tube 3 extrudes reaction products which are formed by previous electric discharge to the outside of an electric discharge path 3. Then, the gas passing through the discharge path 3 returns to the circulation pump 9 from a gas outlet through the piping path 8. In this way, the gas flow rate running through the discharge tube 3 can be set optionally by making the gas injection port 7 approach the discharge path 3 or by changing an opening form of the gas injection port 7. This approach makes the distribution of the gas flow rate in the direction of a discharge path length uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transverse discharge type laser device such as a pulsed discharge Co2 laser or an excimer laser, and particularly to a transverse discharge type laser device such as a pulsed discharge Co2 laser or an excimer laser. The present invention relates to a cross-flow type laser device in which the directions of the two directions are perpendicular to each other.

Conventional technology In transverse discharge laser devices such as excimer lasers,
Reaction products generated in the discharge path by the discharge make the next discharge unstable, leading to a decrease in laser output. Therefore, it is necessary to quickly remove the reaction products in the discharge path before the next discharge starts. A cross-flow type laser device is a laser device that removes reaction products in the discharge path by circulating a gas flow in the discharge tube in a direction perpendicular to the laser optical axis.

Conventionally, in such a loss flow type laser device, a circular fiJ-shaped cross flow fan 1 is installed parallel to the elongated wt and i provided in the discharge tube, and a cross flow fan 1 is provided in a tangential direction from a part of the outer periphery of the cross flow fan 1. The structure is such that the blown gas is guided to the discharge path by a gas flow guide (for example,
(Refer to Kazushi Kawashita et al. ``Development of high-output discharge excitation system ximer laser oscillator,'' 1986, 7th Annual Conference of the Laser Society of Japan, 29aI-13).

Hereinafter, a conventional cross-flow type laser device as described above will be explained with reference to the drawings.

FIG. 3 is a configuration diagram of a cross-section perpendicular to the laser optical axis of a conventional cross-flow type laser device. In Figure 3, 1
is an elongated cylindrical discharge tube filled with a laser gas medium. 2 extends in the longitudinal direction of the discharge tube [discharge occurs at the poles,
Excite the laser gas medium. 3 is a discharge path which is narrowed by the electric current 4iff2 and whose longitudinal axis coincides with the axis of the laser beam. Reference numeral 4 denotes an elongated cylindrical cross-flow fan, whose length in the longitudinal direction is approximately the same as the length in the longitudinal direction of the electrode 2, and is provided in the discharge tube parallel to the electrode 2. The cross flow fan 1 4 is connected to a motor outside the discharge tube 1 via a rotation introduction device (not shown). A gas flow guide 6 guides gas blown out in a tangential direction from a part of the outer periphery of the cross flow fan to the discharge path 3.

With the above configuration, the cycloflow fan 4 is rotated by the external motor of the discharge tube, and the gas blown out in the tangential direction from a part of the outer circumference circulates in the direction shown by the arrow along the gas flow guide 5, causing discharge. The reaction products generated in path 3 are removed.

Problems to be Solved by the Invention However, in the above-mentioned hn configuration, the cross flow fan 1 and 4 must be provided inside the discharge tube 1.
The discharge tube 1 becomes larger. Also, since the gas blowing direction from the cross flow fan 1 and 4 is tangential to the outer circumference,
It is difficult to shorten the distance between the outlet of the cross flow fan 4 and the discharge path 3, and therefore the flow rate of gas passing through the discharge path 3 is reduced due to pressure loss. Furthermore, even if the gas is blown out uniformly along the longitudinal direction of the elongated crossflow channel 14, the sheath-like properties are lost due to the pressure loss until it reaches the discharge path 3, and the discharge tff, The gas flow rate distribution that flows perpendicularly across the area becomes non-uniform. As a result, the next discharge is non-uniform over the longitudinal direction of the discharge path, and the output energy of the laser beam is a value different from the output energy μ of the laser beam generated by the previous discharge. becomes. Therefore, there has been a drawback that the output energy of the laser beam generated each time a discharge, that is, the laser pulse energy, fluctuates.

In view of the above-mentioned drawbacks, the present invention provides a cross-flow laser device that can miniaturize the discharge tube, reduce pressure loss from the gas outlet, and evenly distribute the gas flow rate over the entire length of the discharge path. It is something to do.

Means for Solving the Problems In order to solve the above problems, the cross-flow type laser device of the present invention provides a discharge tube with a gas inlet and a gas outlet, and provides a gas inlet and a gas outlet on the outside of the discharge tube. A gas introduction tube is connected to a circulation pump by pipes respectively connected to the circulation pump and has a gas injection port on the side of the discharge path inside the discharge tube, and the gas injection port is provided so that the gas injection port faces the discharge path, and The introduction pipe is connected to the gas inlet.

Due to this configuration, the gas injection port can be brought close to the discharge path, so that gas can be efficiently sent to the discharge path.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of a cross-flow type laser device in an embodiment of the present invention in a plane perpendicular to the laser optical axis. In FIG. 1, 1 is an elongated cylindrical discharge tube containing a laser gas medium. Reference numeral 2 represents an electrode extending parallel to the direction of the laser optical axis perpendicular to the plane of the paper, and reference numeral 3 represents a discharge path sandwiched by the electric current fM2. 4 is a gas inlet provided on one end face of the discharge tube 1, and 6 is a gas outlet provided at the bottom of the discharge tube 1. 6 is a cylindrical gas introduction tube connected to the gas port 4 and introduced into the discharge tube 1;
installed on the side of the Reference numeral 7 denotes a gas injection port, which opens in the longitudinal direction of the side surface of the gas introduction tube 6 toward the discharge path 3 in the form of a slit. The opening width of the gas injection lower becomes gradually wider 7 from the gas inlet 4 toward the tip of the gas introduction pipe 6.

8 is a pipe, 9 is a circulation pump, gas population 4 and gas outlet 5
is connected to a circulation pump 9 via a conduit 8, and circulates the gas inside the discharge tube 1 in the direction of the arrow.

FIG. 2 is a schematic view of the main parts of the cross-flow type laser device according to the above embodiment of the present invention, seen from the side.

The operation of the cross-flow laser device configured as described above will be described below. First, the circulation pump 9
The gas discharged from the discharge tube 1 is introduced into the discharge tube 1 via the gas port 4 via the conduit 8. A gas introduction pipe 6 is connected to the gas pipe 4, and the gas sent into the gas pipe 4 is blown out from a gas injection lower provided on the side of the gas pipe 6 and immediately flows through the discharge path 3. cross. At this time, the gas crossing the discharge path 3 pushes out the reaction products generated in the previous discharge out of the discharge path 3. and discharge path 3
The gas that has passed through returns from the gas outlet 6 to the circulation pump 1e via the pipe line 8.

As described above, according to this embodiment, the gas injection lower can be brought close to the discharge path 3. Furthermore, by changing the opening shape of the gas injection lower, the gas flow rate across the discharge path 3 can be arbitrarily set, and the gas flow rate distribution in the longitudinal direction of the discharge path can be made uniform.

In the above embodiment, the slit-shaped gas injection lower was provided in the cylindrical gas introduction pipe 6, but the gas introduction pipe 6 may have any shape as long as it can be installed on the side surface of the discharge path. It goes without saying that the shape, position, and number of the gas injection lowers can be arbitrarily set.

Effects of the Invention As described above, the present invention allows the discharge tube to be significantly downsized by providing the gas introduction tube with the gas injection port on the side surface of the discharge path. Further, the decrease in the gas flow rate between the gas injection port and the discharge path can be reduced.

Furthermore, by arbitrarily setting the shape and number of the gas injection ports, the gas flow rate distribution in the longitudinal direction of the discharge path can be made uniform, so that uniform discharge can be performed over the entire longitudinal direction of the discharge path. The output energy of the laser beam can be stabilized. Therefore, there is almost no fluctuation in the laser bus energy, and a stable average power of the laser beam can be obtained, especially during high-return operation.
Its practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a cross-flow laser device according to an embodiment of the present invention, FIG. 2 is a diagram showing the main part of a cross-flow laser device according to an embodiment of the present invention, and FIG. FIG. 2 is a cross-sectional view of a cross-flow laser device. 1...discharge tube, 2...electrode, 3...
...Discharge path, 4...Gas inlet, 5...
・Gas outlet, 6...Gas inlet pipe, 7...
・Gas injection port, 8...Pipeline, 10. Old...Circulation pump.

Claims (1)

[Claims] A discharge tube containing a laser gas medium is provided with at least one set of electrodes extending in the direction of the laser optical axis, the discharge tube is provided with at least one gas inlet and at least one gas outlet, and the discharge tube is provided with at least one gas inlet and at least one gas outlet. The gas in the discharge tube is circulated through the pipe line and the circulation pump, and at least one
A gas introduction tube having two gas injection ports is connected to the gas inlet and introduced into the discharge tube, and the gas introduction tube is provided on the side of the discharge path so that the gas injection ports face the discharge path. A cross-flow type laser device featuring: