JPS6310915B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode structure for an axial silent discharge gas laser device.

A conventional device of this type is shown in FIG. FIG. 2 is a sectional view of the electrode section taken along the - line. In the figure, 1 and 2 are electrodes, 3 is a cylindrical dielectric, and the electrodes 1 and 2 are formed of a thin film of metal closely adhered to the outer wall surface of the dielectric 3 by means of plasma spraying or the like. 4 is deionized cooling water, 5 is an outer cylinder made of an insulator, 6 is a discharge space, 7 is a gas flow,
8 is an AC power supply, 9 is a total reflection mirror, 10 is a partial reflection mirror, 11 is a duct, 12 is a heat exchanger, 13
is a blower, and 14 is a laser beam.

Next, the operation will be explained. From AC power supply 8
A high frequency high voltage of about 50kHz and 10kV is applied to electrodes 1 and 2.
When the gas is applied to the discharge space 6, a silent discharge is generated in the gas (CO ₂ - CO - N ₂ - He mixed gas, pressure about 100 Torr) flowing into the discharge space 6, and the gas is excited by the laser and the total reflection mirror 9 and the partial reflection mirror Oscillation occurs in the optical resonator constituted by laser beam 14 (wavelength 10.6 μm), and the excited molecule energy
can be taken out as light energy. The silent discharge is a stable discharge in which transition to an arc discharge is automatically prevented because the dielectric 3 is interposed between the electrodes 1 and 2. Cooling is necessary to prevent thermal breakdown of the dielectric 3, and cooling water 4 is passed between the outer cylinder 5 and the dielectric 3. However, in order to prevent current leakage from the electrode 1 on the high voltage side, cooling water 4 is passed between the outer cylinder 5 and the dielectric 3. Deionized cooling water 4 is used. The outer cylinder 5 contains deionized cooling water 4
However, since the distance from the electrode 1 is short, it is made of an insulating material to ensure insulation. While the gas stream 7 passes through the discharge space 6
The temperature rises by about 100°C, but it passes through the duct 11 and is cooled to about room temperature by the heat exchanger 12, and then the blower 13
is accelerated and circulated again into the discharge space 6.

Since the conventional device is configured as described above, it is easily damaged because the thickness of the dielectric 3 is restricted due to its function, and it is not possible to use a dielectric with a sufficient thickness. The drawback is that water leaks between electrodes 1 and 2, and deionized cooling water 4
The disadvantage was that it was easy for discharge damage to occur through the tube.

The present invention was made to eliminate the above-mentioned drawbacks of the conventional device, and aims to provide a highly reliable silent discharge type gas laser device by improving the electrode structure.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. FIG. 4 is a sectional view taken along the line of FIG. 3. In the figure, electrodes 1 and 2 are internally cooled with deionized cooling water 4 and have discharge surfaces covered with a dielectric 3. Dielectric 3 is glass, electrodes 1 and 2
is iron, and the dielectric material 3 is bonded to the electrodes 1 and 2 by so-called "enameling". 20 is an insulating member that maintains insulation between the electrodes 1 and 2 and at the same time defines the shape of the discharge space 6.

In the above configuration, a high frequency high voltage is applied between the electrodes 1 and 2 from the AC power supply 8, a silent discharge is generated in the discharge space 6, and a part of the discharge energy is extracted to the outside as optical energy of the laser beam 14.The situation is conventional. However, in this embodiment, the electrodes 1 and 2 are separated by an insulating member 20 that is made of an inorganic insulator and constitutes a gas flow path, so that the discharge space 6 between the electrodes 1 and 2 does not pass through. The risk of dielectric breakdown is virtually completely eliminated. Furthermore, even if the dielectric 3 is damaged, there is no fear that the deionized cooling water 4 will leak into the discharge space 6.

Note that the insulating member 20 is made of a material such as ceramic, and although the surface in contact with the discharge space 6 is exposed to silent discharge, there is no risk of surface deterioration.

FIG. 5 is a diagram of an electrode section according to another embodiment of the present invention. The difference from the first embodiment is that the insulating member 20 has a through hole 21 formed of a slit or a large number of holes.
The gas flow 7 parallel to the optical axis and the discharge space 6 are made to flow into the discharge space 6 from the through hole 21 through the ducts 30 and 31, which is not parallel to the optical axis.
It means merging within. Here, the ducts 30 and 31 are the inflow side and the outflow side, respectively.
They are respectively connected to the inflow side and the outflow side of the duct 11 in the conventional example.

By configuring as above, the discharge space 6
The resistance to the gas flowing through becomes very small, and it becomes possible to use a blower 13 with a small pressure difference (which is inexpensive and easily available).

In the above embodiment, both electrodes 1 and 2 have a structure in which the discharge surfaces are covered with the dielectric material 3, but a structure in which only one of the electrodes is covered with the dielectric material 3 may be used.

Moreover, although the electrodes 1 and 2 are shaped with concave curvature, there is no problem even if they are flat. However, in order to improve the convergence of the laser beam 14, it is preferable that the cross section of the discharge space 6 has a shape close to a circle or a square.

As described above, the present invention includes an optical resonator, electrodes extending in the direction of the optical axis of the resonator and facing each other across the optical axis, and generating a discharge between the two electrodes within the discharge space. a dielectric covering the electrode surface of at least one of the electrodes, a means for cooling the electrode by passing water through the electrode, and a dielectric that covers the electrode surface of at least one of the electrodes; an insulating member made of an inorganic insulating material that airtightly maintains the gas on both sides and forms a flow path for the gas together with the two electrodes, and an AC power source that applies a high frequency and high voltage between the two electrodes. It is characterized by having a structure that generates silent discharge in space, and it is possible to provide a gas laser device with an extremely solid structure, and the reliability of the electrodes can be dramatically improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the configuration of the main parts of a conventional gas laser device, FIG. 2 is a cross-sectional view of the electrode part seen from the - line, and FIG. 3 is a vertical cross-sectional view of an embodiment of the present invention. FIG. 4 is a cross-sectional view of the electrode portion as seen from the - line, and FIG. 5 is a cross-sectional view of the electrode portion of another embodiment of the present invention. In the figure, 1 and 2 are electrodes, 3 is a dielectric, 4 is deionized cooling water, 6 is a discharge space, 7 and 7a are gas flows, 8 is an AC power supply, 9 is a total reflection mirror, 10 is a partial reflection mirror, and 11 , 30, 31 are ducts, 12
13 is a heat exchanger, 13 is a blower, 14 is a laser beam, 20 is an insulating member, and 21 is a through hole. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. An optical resonator, electrodes extending in the direction of the optical axis of the resonator and facing each other across the optical axis, and an electrode intervening at both ends of the opposing surfaces of the electrodes and between the electrodes. A gas laser device comprising an insulating member that defines a distance and a discharge space between the electrodes, and an AC power source that applies a high frequency and high voltage between the electrodes to laser excite gas flowing in the discharge space. . 2. The gas laser device according to claim 1, wherein the insulating member is provided with a through hole that communicates with the discharge space from the lateral direction, and gas is fed into the discharge space through the through hole. . 3. The gas laser device according to claim 1 or 2, wherein the discharge space has a cross-sectional shape close to a circle or a square.