JPS60157280A - Gas laser oscillation device - Google Patents

Abstract

PURPOSE:To reinforce pre-ionization and thus to stabilize discharges by a method wherein a capacitor is connected in parallel between a cathode, one of main electrodes performing discharge, and trigger electrodes; on the other hand, an inductance is connected in parallel between an anode and the trigger electrode. CONSTITUTION:The mesh cathode 10 and the anode 3 opposed thereto are arranged in a laser tube 1. Many trigger electrodes 11 having insulation layers are arranged in the back of the cathode 10, and the cathode 10 and the anode 3 are connected to a pulse power source 4. Further, the capacitor 12 is connected in parallel between the trigger electrodes 11 and the cathode 10, and a stabilizing coil 13 is connected in parallel between the trigger electrodes 11 and the anode 3. The trigger electrodes 11 are successively coated with organic substance 15 and inorganic substance 16 which serve as the insulation layer around a conductor 14. Thereby, the equivalent capacitance between the cathode 10 and the trigger electrodes 11 increases, and the pre-ionization generating therebetween becomes strong, resulting in the promotion of the stabilization of main discharges.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to gas laser oscillation devices such as T EA C02 lasers, excimer lasers, and the like.

[Technical background of the invention and its problems]

FIG. 1 shows a conventional example of a TEA laser oscillation device, which is one type of gas laser oscillation device. That is, a cathode (2) and an anode (3) are arranged facing each other in a laser tube (1).

A pulse power source (4) is connected to them. cathode(
A large number of grooves (5) are provided on the surface of the trigger electrode (2) for stabilizing the discharge, and the trigger electrode (5) is insulated in these grooves (5).
6) is located. Trigger electrode (6) and anode (3)
A capacitor (power is connected between the

In the above device, before the main discharge occurs between the cathode (2) and anode (3), a four-way discharge occurs between the cathode (2) and the trigger electrode (6), and a wide gap between the electrodes occurs. Supply a large amount of electrons or ions. Subsequently, a main discharge is generated between the cathode (2) and the anode (3) using these electrons as initial electrons after some time interval, and the laser-excited molecules are excited.

In the above-mentioned conventional technique, which uses corona discharge as a pre-discharge to stabilize the main discharge, the most important points are the dielectric strength voltage and dielectric constant of the insulator covering the trigger electrode. That is, in order to stabilize the main discharge, it is necessary to supply a large amount of initial electrons or ions, but it is desirable that the capacitance K be as large as the equivalent capacitance between the cathode and the trigger electrode can be. However, in the conventional technology, in order to ensure the required dielectric strength voltage of the insulator covering the trigger electrode, increasing the thickness of the insulator lowers the equivalent capacitance, making it difficult to obtain the required amount of initial electrons and ions. . To solve this problem, it is necessary to use an insulator with a high dielectric strength and a large dielectric constant, but there are no suitable materials for this.

[Purpose of the invention]

An object of the present invention is to provide a high-pressure gas laser oscillation device that requires preliminary ionization, which strengthens the reserve force and stabilizes discharge.

[Summary of the invention]

To achieve the above purpose, a capacitor is connected in parallel between the cathode, which is one of the main electrodes for discharging, and the trigger electrode, and an inductance is connected in parallel between the anode and the trigger electrode. It is configured to do this.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on drawings showing embodiments.

FIG. 2 shows an embodiment of the present invention, in which the same components as those explained in FIG. 1 are given the same reference numerals.

That is, inside the laser tube (1), a cathode a@ in the form of a mesh (porosity: 50%) and an anode (3) are arranged opposite to the cathode a@. A large number of trigger electrodes aD having an insulating layer are arranged behind the cathode α@, and these cathodes (10)
and the anode (3) are connected to a pulsed power source (4).

Furthermore, a capacitor (l) is connected in parallel between the trigger pole (Ll and the cathode aω), and a trigger electrode (11
) and the anode (3) are connected in parallel with the stabilizing coil (1st floor).By the way, as shown in Figure 3, the trigger electrode (11) is centered around the conductor α The structure is such that an organic substance aω and an inorganic substance (1e), which become an insulating layer, are sequentially coated concentrically.
51 Hapolyethylene/resin, tetrafluoroethylene resin.

A resin having a relatively high voltage resistance such as an epoxy resin is preferable, and the inorganic material α6) is selected from glass, alumina, silica, mica, etc. in consideration of sputtering resistance. In addition, in order to suppress excessive discharge and ensure a long life as an electrode, it is important to manufacture the conductor (14) and the organic substance (14) in close contact with each other without creating any voids.

With the above configuration, the equivalent capacitance between the cathode a@ and the trigger electrode α9 increased, the pre-ionization generated between them became strong, and the stabilization of the main discharge was greatly promoted. Also, by making the cathode αD into a mesh shape.

It becomes possible to increase the outer diameter of the trigger electrode αυ.

That is, by increasing the thickness of the insulating layer, it is possible to increase the withstand voltage.On the other hand, the decrease in the equivalent capacitance due to the increase in lead water is compensated for by the capacitor oz.

〔Effect of the invention〕

In order to make the effects of the present invention clearer, the effects of the present invention will be explained with reference to FIG. 4, which is a modified version of FIG. In other words, assuming that the equivalent capacitance between the cathode ([0) and the trigger electrode (Ll) is the capacitor υ,
Let this value be C1, and the value of the parallel capacitance of capacitor U be Cp. On the other hand, if the main discharge starting voltage between the cathode H and the anode (3) is vb, the amount of charge Q1 that passed through the trigger electrode before starting the main discharge is given by Q1=ctVb. vb
is determined by the composition of the laser mixed gas inside the laser tube. Here, electrons or ions in an amount approximately proportional to Ql are supplied near the cathode surface and serve as a trigger for the main discharge. On the other hand, in the present invention, the main discharge lasts about 1 μs, but local instability such as thermal instability and negative ion instability occurs at various locations several hundred nanoseconds after the start of the discharge, making arcing more likely to occur. When arcing occurs, most of the energy injected into the discharge section is consumed in a very small volume, resulting in a decrease in laser output. In order to prevent the occurrence of arcing and to stably maintain the main discharge over a wide area, it is necessary to continuously supply υ electrons or ions to the trigger electrode circle after the start of the main discharge. If the inductance value of the capacitor (12 is provided for this purpose, stored charge Qt = epVbii, stabilizing coil α3) is sufficiently thick compared to the inductance value of the trigger electrode lid wire (251), then It is consumed by the ringing current (26) that charges and discharges the capacitor α (2), and electronic particles or ions (27) are continuously supplied from the trigger electrode circle to the main electrode space, and the main discharge is maintained stably. By using this method, a sufficiently stable discharge could be obtained even if nearly twice the energy was injected between the cathode 00) and the anode (3) as in the conventional method, and the laser output was more than doubled. We are getting results. In addition, arcing is suppressed within the same injection energy range as in the past, helping to stabilize laser output.

In the above embodiment, the cathode is a mesh-like electrode, but the present invention is not limited to this, and substantially the same effect can be obtained by using a grooved electrode or a flat plate electrode. In addition to the TEACO2 laser, it can also be applied to pulse discharge excited CO2 lasers, excimer lasers, etc. Furthermore, the effect is the same even if the trigger electrode is of a single configuration instead of a plurality of trigger electrodes.

[Brief explanation of drawings]

, FIG. 1 is a schematic diagram showing a conventional example, FIG. 2 is a schematic diagram showing an embodiment of the present invention, FIG. 3 is a cross-sectional view of a trigger electrode, and FIG.
The figure is a schematic diagram for explaining the invention in detail. (1)... Sea f W (4)... Pulse power supply (3
)...Cathode (11)...Cathode (1 piece...Capacitor (13)...Stabilizing coil agent Patent attorney
Kensuke Noriyuki (and 1 other person)

Claims (4)

[Claims] (1) A main electrode disposed facing the gas medium to be excited by the laser and discharging at the source of the gas medium, a trigger electrode disposed near one of the main electrodes, a power supply for generating the discharge, and the above. In a gas laser oscillation device comprising one or more pairs of resonator mirrors arranged opposite to each other in order to collect laser light excited by discharge, a capacitor is connected in parallel between the trigger electrode and the cathode, and the trigger A gas laser oscillation device characterized in that a stabilizing coil is connected between an electrode and an anode. (2) ') The gas laser oscillation device according to claim 1, wherein the gami electrode is arranged behind the cathode. (3) The gas laser oscillation device according to claim 1 or 2, wherein the cathode is a mesh-like electrode. (4) ') Gas laser oscillation according to claim 1, wherein the Gami pole has a multilayer structure in which a conductor is concentrically coated with an organic substance, and the organic substance is further concentrically coated with an inorganic substance. Device.