JPS62145787A - Gas laser generator - Google Patents

Abstract

PURPOSE:To improve a laser light output by containing special amount of high melting point metal member in a conductive metal member on a discharge surface partly covered with an insulating member at the downstream side of mixture gas to prevent fine metal particles from adhering to a mirror. CONSTITUTION:A disclike cathode 12 is composed of a central hole 14, and a plurality of auxiliary holes 15 disposed around the central hole. A discharge surface 16 is formed on the inner peripheral surface of the hole 14. The entire cathode except the surface 16 is covered with an insulating film 17 such as boron. The cathode contains as a conductive metal member such as 40% of main component such as copper and 60% of high melting point metal member such as W. The surface 16 is melted due to high temperature at glow discharging time and burning time, but 60% of W is contained in the main content Cu to be hardly melted, the surface 16 is always cleaned by melting the main content, and hardly transferred to a partial glow discharge. Thus, a laser light output can be improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a gas laser generator with improved electrodes.

[Conventional technology]

In general, axial flow type gas laser generators are, for example, USP4
．． As shown in Publication No. 331,939 or Japanese Unexamined Patent Publication No. 60-4289, a discharge tube is filled with a mixed gas of CO2, N2, He, etc., mirrors are provided at both ends of the discharge tube, and mirrors are provided at both ends of the discharge tube. Cooling channels and electrodes are arranged to circulate the mixed gas from the center to the center. The electrode consists of a cylindrical anode and a ring-shaped cathode.

As the cathode member, a conductive metal member such as oxygen-free copper or aluminum or a high melting point conductive metal member is usually used.

A direct current voltage is applied between the two electrodes to form a glow discharge between the two electrodes. The cathode is coated with an insulating film, such as boron or a ceramic material, on a portion other than the discharge surface to spread glow discharge over the entire surface of the discharge surface to prevent transition to arc discharge due to local overheating.

[Problem that the invention seeks to solve]

However, due to the temperature during the glow discharge, a part of the insulating coating burns and becomes carbon C, which adheres to the insulating coating and the discharge surface due to the vortex flow of the mixed gas having a high flow rate. Then, the discharge area of the discharge surface decreases, and the entire glow discharge shifts to a partial glow discharge, and finally becomes an arc discharge. During partial glow and arc discharge, due to the temperature during combustion of the insulating coating, fine metal particles melted by the conductive metal member on the discharge surface may adhere to the mirror, reducing the laser light output.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas laser generator that improves laser light output by preventing fine metal particles from adhering to a mirror.

[Means for solving problems]

In the electrode of the present invention, at least the discharge surface on the downstream side of the mixed gas, which is partially covered with an insulating member, is made of a conductive metal member with a diameter of 40 to 60 mm.
(%) of high melting point metal members, the above problems were solved.

[Effect]

Since the electrode in the glow discharge state is composed of a conductive metal member containing 40 to 60 (%) of a high melting point metal member, the amount of melting of the conductive metal member is reduced, and molten metal fine particles are deposited on the mirror. It is less likely to stick and the laser light output is improved.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

The axial flow gas laser generator 1 includes a discharge tube body 2 and a cooling path 3.
It consists of. The discharge tube body 2 is composed of an insulating tube 4 and a communication tube 5. Reflection mirrors 6 are provided at both ends of the communication tube 5.
and an output mirror 7 is attached. The lower end of the communication pipe 5 communicates with the cooling path 3. Inside the cooling path 3 is a heat exchanger 8
and a blower 9 are arranged. When the blower 9 is rotated, the mixed gas 10 flows in the direction of the arrow, circulates between the discharge tube body 2 and the cooling path 3, and the mixed gas 10 whose temperature has increased in the discharge tube body 2 is transferred to the heat exchanger 8. to cool it down and feed it into the connecting pipe 5 again. The communication tube 5 surrounds both ends of the insulating tube 4 to constitute the discharge tube body 2. Inside the discharge tube body, an anode 11 and a cathode 12 are arranged correspondingly. The anode 11 is formed into a cylindrical shape, and has a discharge surface formed on the inner surface of the cylindrical shape. A cathode 12 is supported on an inclined surface 13 formed in the communication tube on the reflecting mirror side.

As shown in FIGS. 1A and 1B, the circular cathode 12 is composed of a center hole 14 and a plurality of auxiliary holes 15 arranged around the center hole.

The discharge surface 16 is formed on the inner peripheral surface of the center hole 14.

An insulating coating 17, such as boron, is coated over the entire cathode except for the discharge surface 16. The cathode is composed of a conductive metal member containing Cu as a main component, for example, 40 (%), and Cu containing 60 (%) of W, which is a high melting point metal member.

With this configuration, a DC voltage is applied between the anode 11 and the cathode 12 to generate glow discharge G at both electrodes.

When a glow discharge is performed for a long time, a vortex 20 generated by the flow of the mixed gas 10, as shown by the chain line in FIG.
A portion 18 of the insulating coating 17 near the discharge surface on the downstream side is burned, and carbon C is attached to the discharge surface 16. The discharge surface 16 melts due to the high temperature during glow discharge and combustion, but since it contains 60 (%) tungsten W as a main component of Cu, it is difficult to melt and the discharge surface 16 melts due to the melting of the main components. The surface 16 is constantly cleaned and is less prone to partial glow discharge. Therefore, the laser beam 19 is transmitted to the mirror 6.
7, the reflectance and transmittance do not deteriorate, making it possible to improve the laser light output, and the glow discharge G is performed over the entire surface, making it difficult to shift to a partial glow discharge, further improving the laser light output. can be done. Moreover, when the weight of tungsten W becomes 60 (%) or more, the main component becomes less, and the glow discharge G becomes difficult to ignite on the discharge surface 16, and the amount of the main component melted is small, causing it to adhere to the discharge surface 16. It is difficult to remove the carbon C present in the discharge, and the discharge area decreases, causing local overheating and transitioning to arc discharge. Also, the weight of tungsten W is 40
(%) or less, a large amount of molten metal fine particles from the main component will adhere to both mirrors 6.7, and the output efficiency of the laser beam 19 will deteriorate, making it unusable.

That is, as shown in FIG.
) Cu = 60-40 (%) in combination with the mixing weight ratio
, W=40-60 (%), the laser light output could be improved by the cleaning action.

In the two series of embodiments, the entire cathode was made of a Cu-W alloy, but the discharge surface 16 was made of Cu, not only the entire electrode but also only a part corresponding to the downstream part of the mixed gas [8].
-W alloy, and the remaining portion may be made of metal such as CI3 or AQ. In addition, Ag-W alloy is used for the double cathode and anode.

Cu-Fe alloy, Cu-Cr alloy, etc. are used, and these alloys have a content of 40 to 60 (%) in the main components (Cu, A, g).
) containing high melting point metal members (W, Fe, Cr). Further, the electrode can be used in a rod shape, a band shape, etc.

〔Effect of the invention〕

As described above, according to the gas laser generator of the present invention, the laser light output can be improved.

[Brief explanation of drawings]

Figure 1 (A) is a plan view of the cathode used in Figure 2, Figure 1 (B) is a sectional view taken along the line nn of Figure 1 (A, ), and Figure 2 is an example of the present invention. 3 is a schematic side sectional view showing the discharge region of FIG. 1, and FIG. 4 is a characteristic diagram showing the composition ratio of the cathode material used in FIG. 1. 2...Discharge tube body, 6,7...Mirror, 1o...
Mixed gas, 11... Anode, 12... Cathode, 17...
・Insulating coating.

Claims (1)

[Claims] 1. A mixed gas is passed through a discharge tube having mirrors at both ends, and glow discharge is caused between electrodes of a high-melting point conductive metal member arranged in the discharge tube and coated on at least one side with an insulating material. In a device that converts mixed gas into laser light, an electrode coated with an insulating member is coated with a conductive metal member having a 40 to 60
%) of a high melting point metal member. 2. The above electrode is a conductive metal member of Cu or Ag with 40~
2. The gas laser generator according to claim 1, wherein the gas laser generator comprises an alloy containing 60% of one high-melting point metal member selected from W, Cr, and Fe.