JPS639174A - Discharge apparatus for gas laser - Google Patents

Abstract

PURPOSE:To cause a main discharge region to be irradiated uniformly and fully with UV energy for preliminary ionization generated by preliminary ionization electrodes by a method wherein protrusions are provided on a cathode-side surface of main ionization electrodes, or on both sides in the cross section, and the preliminary ionization electrodes are positioned to face the protrusions. CONSTITUTION:On the surface of a cathode-side electrode 1 of main discharge electrodes 1 and 2, or on both sects in the cross section, protrusions 3 are provided, confronted with by preliminary ionization electrodes 4. Preliminary ionization takes place between the preliminary electrodes 4 and protrusion 3 prior to a main discharge between the main discharge electrodes 1 and 2, and the UV energy generated by the preliminary ionization lands on the area on top of the cathode-side main discharge electrode 1. With the gaps involving the preliminary electrodes 4 being located near the cathode-side main discharge electrode 1 and facing the protrusions 3, the top and the areas nearby of the cathode-side main discharge electrode 1 is uniformly and fully irradiated with the UV emitted by preliminary ionization.

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial application field of the invention relates to discharge devices for gas lasers, for example excimer lasers.

In conventional gas lasers, especially excimer lasers, a preliminary step 1! is used to ionize the discharge region gas of this main discharge before the main discharge. The separation method greatly affects laser performance. The preliminary VT separation method for a medium-sized discharge-excited excimer laser is as follows:
The common method is to use a spark gap to prepare ultraviolet rays.

In order to obtain a uniform glow discharge in the main discharge, it is necessary to uniformly irradiate the entire main discharge region with ultraviolet light during preliminary ionization.

Conventional pre-ionization methods include those shown in FIGS. 3 and 4. In the conventional example shown in FIG. 3, preliminary ionization electrodes c and d are provided on both sides of the main discharge electrodes α and b, which face each other in parallel with the opposing direction of the main discharge electrodes α and b. Sparks caused by the preliminary separation electrodes c and d are generated on both sides of the opposing intermediate portions of the main discharge electrodes α and b.

In the conventional example shown in FIG. 4, one electrode -9t of the preliminary ionization electrode is placed opposite to the 'dL pole α on the cathode side of the main discharge electrodes α, b.

Problems to be Solved by the Invention The former of the above conventional examples can uniformly irradiate the main discharge region, but due to insulation problems, it is not possible to bring the spark gap of the spare pole C9d close to the main discharge region. However, there was a frequent problem that the intensity of the ultraviolet light that was irradiated was weakened.

In addition, in the latter conventional example, the spark gap of the pre-ionization electrode can be brought closer to the main discharge region, but it is difficult to uniformly irradiate the main discharge region with ultraviolet light without affecting the main discharge. Ta.

Means and Effects for Solving the Problems The present invention was conceived in view of the above, and has the foregoing [1]
The purpose of the present invention is to provide a gas laser discharge device that can uniformly and intensely irradiate the main discharge region with pre-ionizing ultraviolet light from the 1E separation electrode. A protrusion is provided on the surface of the electrode 1 on the cathode side and on the side part of the cross-sectional shape, and a preliminary ionization electrode is placed opposite to this protrusion. Ionization occurs, and the ultraviolet light at this time is irradiated onto the surface side of the main discharge electrode on the cathode side.

Example An embodiment of the present invention will be described based on FIGS. 1 and 2.

In the figure, 1 is a 7it electrode on the cathode side for main discharge, and 2 is an electrode on the anode side. Both electrodes 1.2 face each other with a predetermined interval. The opposing surfaces of both electrodes 1 and 20 have a gentle mountain shape. Projections 3.3 are provided on both sides of the cross-sectional shape of the electrode 1 on the cathode side of the tube as the pole, and each projection 3.3 has a pre-ionization electrode 4.
The tips of the two are opposed to each other with a predetermined gap between them. The height of the protrusion 3.3 is lower than the top surface of the electrode 1. Note that 5.6 is a supply port and an exhaust port for laser medium gas provided on both sides of the main discharge electrode 1 on the cathode side, and the laser medium gas supplied from the supply port 5 is supplied to the main discharge electrodes 1 and 2. It is designed to be discharged from the exhaust port 6 through the space.

The circuit for the power source of the main discharge electrode 1.2 and the preliminary ionization electrode 4.4 is shown in Figure @2. In the figure, 7 is a charging capacitor, 8 is a discharging capacitor, and 9 is a thyratron.

In the above configuration, the main discharge electrode! , 2, preliminary ionization is performed between the preliminary ionization electrodes 3, 3 and the protrusion 4.4 of the main discharge electrode 1 on the cathode side. The ultraviolet light resulting from this pre-ionization irradiates the vicinity of the top surface of the main discharge electrode 1 on the cathode side. At this time, since the gap between the pre-ionization electrodes 3.3 is close to the main discharge electrode 1 on the cathode side and faces the protrusions 4, 4, the pre-ionization electrodes 3. The ultraviolet light generated by the separation uniformly irradiates the vicinity of the top of the main discharge electrode 1 on the cathode side, and is irradiated with high intensity.

Effects of the Invention According to the present invention, the pre-ionization t=4.4 pre-1! The main discharge region can be irradiated with ultraviolet light evenly and in a controlled state. Further, according to the present invention, the distance d between the pre-fiI electrodes 3 and 11 on the anode side can be made smaller than the distance between the main discharge electrodes 1.2, so that the main discharge can This can be suppressed from occurring at the separate V electrodes 3, 3. Furthermore, the protrusions 4, 4 facing the pre-ionization electrode 3.3 are provided protruding into the path of the laser medium gas, thereby providing a cooling equalization effect for the electrodes.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of the main part of the present invention, FIG. 2 is an electric circuit diagram, and FIGS. 3 and 4 are configuration explanatory diagrams showing a conventional example. 1.2 is the main discharge pole, 3,3 is the protrusion, and 4.4 is the pre-ionization pole.

Claims (1)

[Claims] It is characterized in that protrusions 3, 3 are provided on the surface of the cathode side electrode 1 of the main discharge electrodes 1, 2 and on the side portions of the cross-sectional shape, and pre-ionization electrodes 4, 4 are made to face the protrusions 3, 3. gas laser discharge device.