JPH0268971A - Sealed CO↓2 laser tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a sealed CO2 laser tube.

BACKGROUND ART FIG. 4 shows the structure of a conventional sealed CO2 laser tube, in which 21 is a sealed discharge tube containing a mixed gas such as CO2, N2, He, etc., 22 is an anode, and 23 is a sealed discharge tube. and 24 are cathodes, which apply a DC voltage between these anode and cathode electrodes to cause discharge. Optical components including an output coupling mirror 25 and a total reflection mirror 26 are installed at both ends of the discharge tube 21 to form an optical resonator.

In the case of a CO2 laser, the lower the gas temperature, the more advantageous it is to form population inversion for laser oscillation, resulting in high output. Therefore, a cooling jacket 27 is usually provided around the discharge tube 21 for cooling.

Problems to be Solved by the Invention By the way, in the sealed CO2 laser tube as described above, dissociation due to CO2 discharge as shown in equation (1) below occurs:
The equilibrium point of the reaction is the consumption of 02'C'ffi by oxidation,
Or 02 or CO to the sputtered film generated near the electrode.
Due to the adsorption of CO2, the dissociation reaction of the right egg in equation (1) increases, the balance of the dissociation and recombination mechanism is disrupted, and eventually a CO2 deficiency occurs and the laser output changes as shown in curve A in Figure 5. decreases in a short period of time. For this reason, by constructing the cathodes 23 and 24 with a material made of a perovskite oxide sintered body such as La5rCo03, they are made to have electrical conductivity as electrodes, and because they are oxides, there is no oxidation of the electrodes, and there is less spatter. Furthermore, the catalytic action of Co is added to promote the recombination reaction of formula (1), making it possible to extend the operating life as shown by curve B in FIG. However, even with this configuration, there is a limit to the operating life due to the decrease in the catalytic ability of the perovskite oxidation electrode.
Furthermore, there was a problem in that it was difficult to extend the service life.

Therefore, an object of the present invention is to provide a sealed CO2 laser tube that can solve the above problems.

Means for Solving the Problems In order to solve the above problems, the sealed CO2 laser tube of the present invention comprises a predetermined discharge electrode made of a perovskite oxide sintered body, and a platinum group material on the outer or inner surface thereof. The catalyst is equipped with a catalyst supported on it.

Effect In the above configuration, when a DC voltage is applied from the outside between the electrodes, a discharge occurs, and at the same time, the CO2 gas inside the discharge tube is
O and 1. /202, but due to the catalytic ability of the perovskite oxide and the catalytic ability of the catalyst provided on its outer or inner surface, it is immediately recombined into CO2, and the laser output does not decrease over a long period of time. moreover,
When the tip surface of a predetermined discharge electrode made of a perovskite oxide sintered body is covered with a catalyst, discharge at the electrode tip surface is eliminated and spatter is reduced.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Fig. 1, 1 is a discharge tube filled with a mixed gas such as CO2, N2, He, etc., 2 is an anode, 3 and 4 are
This is a cathode made of a perovskite oxide sintered body having catalysts 5 and 6 formed by supporting platinum on an alumina-based carrier closely attached to the outer surface thereof. Moreover, optical components including an output coupling mirror 7 and a total reflection mirror 8 are installed at both ends of the discharge tube 1, forming an optical resonator. Further, a cooling jacket 9 is provided around the discharge tube 1 to lower the temperature of the internal gas during discharge.

In such a configuration, the anode 2 and the anode f! made of the herovskite oxide sintered body. When a DC voltage is applied from the outside during 3.4, a discharge occurs, and at the same time the CO2 inside the discharge tube 1
The gas is converted into CD and 1/202 by the dissociation reaction of the above formula (1).
However, due to the catalytic ability of the perovskite oxide at the cathode 3゜4 and the strong catalytic ability of the catalysts 5 and 6, which have platinum supported on an alumina-based carrier provided on the outer surface, it is immediately recombined into CO2. As a result, as shown by curve C in FIG. 5, a Nagano sealed CO2 laser tube is achieved in which the laser output does not decrease over a long period of time.

By the way, in the above configuration, since the discharge of the cathode part is carried out in the herovskite oxide sintered body part, there is very little sputtering of the electrode, and there is no problem such as electrode oxidation. Heating to generate catalytic activity is achieved by heat conduction of heat generated by electric discharge in the perovskite oxide sintered body, and for this reason, the perovskite oxide sintered body is difficult to heat efficiently during production. They are manufactured in close contact with each other to ensure good conduction, but as shown in FIG. 2, it is effective to bond them closely with an inorganic binder 10 made of alumina or silica. Note that organic binders are not preferable because they generate impurity gases when heated to high temperatures, and there is a risk of a decrease in laser output.

Furthermore, even though it is a perovskite oxide electrode, some sputtering occurs due to long-term discharge, but most of the sputtering is due to ion* bombardment, especially at the tip edge.As a result, the perovskite oxide electrode Touch the tip of 3 (4) to the outside surface! iX5 (6)
By extending and covering the tip, discharge at the tip edge is eliminated, spatter is reduced, and the service life can be extended.

Moreover, although the above description has been made on the assumption that the catalyst is provided on the outer surface of the perovskite oxide electrode, it goes without saying that the same effect can be obtained even if the catalyst is provided on the inner surface.

Effects of the Invention As described above, according to the configuration of the present invention, a predetermined ? While maintaining the properties of perovskite oxide such as conductivity, low spatter, and no electrode arrangement in the 8 electrodes, the catalyst provided on the surface reduces the catalytic ability of the electrode formed of perovskite oxide. Therefore, it is possible to extend the life of the discharge tube. Furthermore, by covering the tip surface of a given discharge electrode made of perovskite oxide sintered body with a catalyst, discharge at the electrode tip surface is eliminated, spatter is reduced, and the life of the discharge tube is further extended. can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a schematic configuration of a sealed CO2 laser tube in one embodiment of the present invention, Figs. 2 and 3 are enlarged sectional views of main parts in other embodiments, and Fig. 4 is a conventional example. FIG. 5 is a side view showing a schematic configuration of a sealed CO2 laser tube, and FIG. 5 is a graph showing laser output characteristics with respect to operating time of the laser tube. I...discharge tube, 3,4...cathode, 5.6...catalyst, 10...inorganic binder. Figure 2 Figure 3

Claims (2)

[Claims] 1. A sealed CO_2 laser tube in which a predetermined discharge electrode is constructed of a perovskite oxide sintered body, and a catalyst supporting a platinum group material is provided on the outer or inner surface of the discharge electrode. 2. 2. The sealed CO_2 laser tube according to claim 1, wherein a tip surface of a predetermined discharge electrode made of a perovskite oxide sintered body is covered with a catalyst.