JPH0541566Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a metal vapor laser device, and particularly to the structure of a discharge electrode.

[Conventional technology]

First, the general structure of a metal vapor laser device will be explained using diagrams.

As shown in FIG. 1, the metal vapor laser device mainly includes a discharge tube 11, a power source 12, a gas supply device 13, and a vacuum pump 14. The discharge tube consists of a ceramic tube 17 that holds metal vapor as a laser medium, a pair of discharge electrodes 18 installed opposite to each other at both ends of the ceramic tube, a heat insulating material 16 wrapped around the ceramic tube 17 to keep it at a high temperature, and It comprises a heat-resistant glass tube 15 for storing therein and a discharge tube outer cylinder 11 for supporting them, and is configured concentrically.

Next, the operation of the metal vapor laser device will be briefly explained.

buffer gas supplied from the gas supply pipe 13;
For example, neon gas is supplied by vacuum pump 14.
Holds at 10Torr. When a high voltage is applied between the discharge electrodes 18, the buffer gas becomes ionized, that is, discharges, and a discharge current flows between the two electrodes. At this time, the metal grains, such as copper, placed in the ceramic tube 17 are melted by the heat of the discharge and further turned into vapor, causing a laser action.

The present invention relates to the structure of a discharge electrode, as shown in the area surrounded by a dashed line in FIG.

[Problem that the invention attempts to solve]

The electrode structure of a conventional metal vapor laser device is shown in FIGS. 3a and 3b. FIG. 3a shows the case where the discharge electrode 18 is placed inside the ceramic tube.
In this case, ions of ionized gas generated by discharge inside the ceramic tube or electrons move to the discharge electrode 18. In this movement, ions are attracted to the cathode side and electrons are attracted to the anode side due to the voltage applied between the electrodes. At this time, the ions or electrons collide with the cathode or anode with high energy. For this reason, each electrode is heated and reaches a high temperature, or is damaged by impact. Then, over time, the structure begins to flake off. In addition, ceramic tubes near the electrodes may be damaged by direct collision with ions or electrons, or by localized thermal stress due to local heating of the electrodes due to a certain amount of heat or local electric field concentration due to damage. may reach. This damage may progress gradually and cause the ends of the ceramic tube to separate, or it may develop into cracks that lead to destruction of the tube itself. Figure 3-
In case 1, the structure is such that the discharge electrode is likely to peel off and the ceramic tube may be damaged. In the case of FIG. 3-2, the frequency of peeling and breakage is lower than in the case of FIG. 3-1, but damage to the end of the ceramic tube can be seen. Such flaking and breakage further promotes non-uniformity of the applied electric field, which has the disadvantage of inviting flaking and breakage of the electrodes and ceramic tubes during acceleration.

The metal vapor laser device of the present invention has a ceramic tube as a part of the discharge tube, a pair of discharge electrodes installed opposite to each other at both ends of the ceramic tube, and a sheath made of ceramic installed at the tip of the discharge electrode.

〔Example〕

Next, one embodiment of the present invention will be described with reference to the drawings.

FIGS. 2a and 2b are cross-sectional views of an embodiment of the present invention, showing the vicinity of the discharge electrode surrounded by a dashed line in FIG. 1.

In FIG. 2a, the tip of the discharge electrode 18 is installed concentrically inside the ceramic tube 17 and extends several centimeters deeper than the end of the ceramic tube 17. A ceramic sheath 21 having a shape as shown in the figure is installed in the radial gap between the discharge electrode 18 and the ceramic tube 17. This sheath prevents ions or electrons from directly colliding with the end of the electrode, and also prevents them from colliding with the end of the ceramic tube 17.
It serves to prevent the heat of the discharge electrode 18 from being directly transferred to the ceramic tube 17. That is, the sheath 21 protects the discharge electrode 18 and the tip of the ceramic tube 17 from direct irradiation with ions or electrons, and also protects the discharge electrode 18 from direct irradiation with ions or electrons.
This non-uniform heat distribution has the effect of preventing thermal stress from being applied to the ceramic tube 17.

In FIG. 2b, the tip of the discharge electrode 18 is installed concentrically outside the ceramic tube 17 and extends into the depth of the ceramic tube 17 by several centimeters. A ceramic sheath 21 having a shape as shown in the figure is inserted into the radial gap between the discharge electrode 18 and the ceramic tube 17. This sheath serves to reduce the impact of ions or electrons on the end of the ceramic tube 17. That is, the sheath 21 has the effect of reversing damage to the end of the ceramic tube caused by ions or electrons. Since the sheath 21 is inexpensive and easy to replace, the life of the metal vapor laser device can be kept long and inexpensive by replacing it quickly when damage occurs.

[Effect of idea]

As explained above, according to the present invention, it is possible to achieve longer life and lower cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view for explaining the metal vapor laser device of the present invention, and FIGS. 2 a and b are longitudinal cross-sectional views of the discharge electrode and its vicinity surrounded by a dashed line in FIG. An example is shown. FIGS. 3a and 3b are longitudinal sectional views of a conventional discharge electrode and its vicinity. 11...Discharge tube, 12...Power source, 13...Gas supply device, 14...Vacuum pump, 15...Heat-resistant glass tube, 16...Insulating material, 17...Ceramic tube, 18...Discharge electrode, 19 ...Laser window, 21...sheath.

Claims (1)

[Scope of utility model registration request] What is claimed is: 1. A metal vapor laser device comprising a ceramic tube and a pair of discharge electrodes disposed opposite to each other at both ends thereof, the metal vapor laser device being characterized in that a tip of the discharge electrode is covered with a sheath made of ceramics.