JPS62249491A - Electrode for gas laser device - Google Patents

Abstract

PURPOSE:To generate a corona discharge of high preliminary ionization effect and excite laser medium in a glow discharge part uniformly and improve the laser output by a method wherein a plate cathode is provided facing an insulating layer and protrusions which are protruded toward the insulating layer are formed at circumferences of a plurality of apertures of the plate cathode and, further, curved surfaces are provided at the other circumferences of the apertures. CONSTITUTION:A circular aperture 7 is formed in a plate cathode 1 by pushing a pin shape tool 14 to the direction of an arrow to pierce the plate cathode 1. At two circumferences of the apertures 7, a curved surface 7a and a saw-teeth protrusion 7b are respectively formed. The plate cathode 1 is so arranged as to make the protrusions 7b protruded toward an insulating layer 9b. If a pulse voltage is applied between the cathode 1 and an anode 2 by a high voltage pulse source 5, the voltage between the cathode 1 and an auxiliary electrode 8, which is at the same potential as the anode 2, starts ascending and a corona discharge is induced on the surfaces of the saw-teeth protrusions 7b. As the saw-teeth protrusion 7b has a shape which induces intense electric field concentration, hard ultraviolet rays which have high transmitting power can be generated. Therefore, a main discharge region 6 can be uniformly ionized prelimirarily by the hard ultraviolet rays transmitted through the apertures 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrode for a gas laser device, and particularly to an electrode equipped with pre-ionization means suitable for a lateral excitation type gas laser device.

[Conventional technology]

A related device of this type is, for example, US Pat. No. 3,662,284. The electrodes of this device are constructed as follows. As pre-ionization electrodes, an auxiliary N pole and a grid-shaped balance are arranged with an insulating layer interposed therebetween, and as main discharge electrodes, a grid-shaped anode and a cathode are arranged.

First, preliminary ionization is performed by corona discharge on the surface of the grid-shaped anode, and then glow discharge is performed between the main discharge electrodes to excite the laser medium.

[Problem that the invention seeks to solve]

The above conventional technology does not take into account the 'ttt pole shape that generates corona discharge suitable for pre-ionization, and due to insufficient pre-ionization, the main discharge glow discharge shifts to arc discharge, resulting in laser output. There was a problem in that the increase in the amount of water was prevented.

The purpose of the present invention is to generate corona radiation I having a high pre-ionization effect, uniformly excite the laser medium of the glow discharge part,
The object of the present invention is to provide an electrode that can increase laser output.

[Means for Solving Problem 1] The above object is to arrange a plate-shaped cathode facing an insulating layer, provide a plurality of openings in the plate-shaped cathode, and form an insulating layer around the periphery of the opening. This can be achieved by forming a protrusion projecting in the direction and also by forming the other peripheral edge of the opening into a curved shape.

[Effect]

First, a corona discharge is generated on the surface of the protrusion of the opening for preliminary ionization. At this time, since the protrusion has a large electric field concentration shape, is the corona discharge large? J! As the flow increases, hard ultraviolet rays with high penetrating power are obtained.

This hard ultraviolet light passes through the aperture and uniformly pre-OR-ionizes the laser medium in the main discharge region. A similar glow discharge is established. At this time, since the fi1 surface shape portion has a shape that relaxes the electric field, glow discharge does not transition to arc discharge. Therefore, the laser medium can be excited efficiently and the laser output can be increased.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an explanation will be given with reference to FIGS. 1 and 2 showing an electrode for attaching a lateral excitation/atmospheric pressure operating type carbon dioxide laser, which is an embodiment of the present invention.

A cathode 1 and an anode 2 are arranged as main discharge electrodes. The electrodes 1.2 are connected to a high-voltage pulse source 5 via mounting plates 3, 4, respectively. The cathode 1 is provided with a plurality of circular openings 7 corresponding to the main radiation fL area 6.

A cathode 1 and an auxiliary electrode 8 are arranged as preliminary ionization electrodes. The auxiliary electrode 8 is electrically insulated from the cathode 1 and the mounting plate 3 by an insulating box 9 consisting of an insulating plate 9a (!: insulating layer 9b).
electrically connected to.

Note that the laser output 10 is taken out from a laser co-losser consisting of a reflecting mirror 11 and an output mirror 12.

Next, the shape of the circular opening 7, which is the main point of an embodiment of the present invention, will be explained in detail with reference to FIGS. 3 and 4. Third
As shown in the figure, a circular opening 7 is formed by pressing a pin-shaped tool 14 in the direction of the arrow to penetrate the plate-shaped cathode 1 arranged in a jig A13 having a tapered hole. At this time, as shown in the fourth section, the two peripheral edges of the opening 7 are provided with a curved surface portion 7a and a sawtooth protrusion portion 7b, respectively.
is formed. The cathode 1 is arranged so that the sawtooth protrusions 7b protrude toward the insulating layer 9b.

First, when a pulsed pressure is applied between the cathode 1 and the anode 2 by the high-voltage pulse generation source 5, an auxiliary voltage having the same potential as the anode 2 is applied.
The voltage between the ζ pole 8 and the cathode 1 begins to rise, and corona discharge occurs on the surface of the sawtooth protrusion 7b. Since this sawtooth protrusion 7b has a shape that allows a large concentration of electric field, hard ultraviolet rays with large penetrating power are generated.

Therefore, the hard ultraviolet rays passing through the opening 7 uniformly spread the main discharge region 6 into the preliminary i! It has the effect of letting you go. Although the protrusion 7b is formed in a sawtooth shape here, the same effect as above can be achieved if the protrusion has a protrusion shape that protrudes toward the insulating layer 9b.

Next, when the pulse voltage increases and finally reaches the discharge starting voltage between the electrodes 1.2, a uniform glow discharge is established in the main discharge region 6 due to the uniform preliminary charge described above. At this time, glow discharge occurs in the curved portion 7a where electric field concentration is small, so transition to arc discharge can be prevented. Therefore, the laser medium in the main discharge region 6 can be excited uniformly.

According to one embodiment of the present invention, a pin-like tool 1 is attached to a plate-like cathode 1.
By penetrating the electrode 4, the curved surface portion 7a and the serrated protrusion portion 7b can be formed, making it easy to manufacture the electrode.

A modification of the present invention will be explained with reference to FIG. In the same figure,
The part corresponding to the auxiliary electrode 8 is divided into auxiliary heavy poles 8a and 8b, and the auxiliary 11 pole 8a is switched to the anode 2 by the changeover switch 15.
Connect to. In this case, since preliminary ionization is performed only through the opening 7 corresponding to the auxiliary Nd 18a, the size of the main discharge region 6 can be limited. Therefore, the changeover switch 15
By this operation, the size of the main discharge region 6, that is, the size of the laser beam cross section can be changed.

In the above embodiments, the opening 7 has a circular shape, but it is also possible to form an elliptical shape, a slit shape, etc., with curved portions and protrusions on the periphery of the opening.

〔Effect of the invention〕

According to the present invention, the plurality of openings provided in the plate-shaped cathode include protrusions that can generate corona discharge with a high pre-ionization effect, and curved portions with small electric field concentration that prevent glow discharge from transitioning to arc discharge. Therefore, the laser medium can be excited uniformly and the laser output can be increased.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an electrode section for a lateral excitation/atmospheric pressure operating type carbon dioxide laser device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1 with connection between the electrodes added, Fig. 3 is a cross-sectional view showing the method of forming the opening, Fig. 4 is an enlarged cross-sectional view of the opening, and Fig. 5 is a cross-sectional view showing the method of forming the opening. The figure is a sectional view of a modification of the present invention. 7b... Serrated projection.

Claims (1)

[Claims] 1. An electrode for a gas laser device comprising a cathode and an anode for laser medium excitation, and an auxiliary electrode facing the cathode with an insulating layer interposed therebetween, wherein the cathode is provided with a plurality of openings, and the openings An electrode for a gas laser device, characterized in that a protrusion protruding toward the insulating layer is formed on a peripheral edge of the electrode. 2. The electrode for a gas laser device according to claim 1, wherein the protrusion has a sawtooth shape. 3. The electrode for a gas laser device according to claim 1, wherein the auxiliary electrode is divided into a plurality of parts.