JPH02267982A - High-frequency discharge-excited co2 gas laser - Google Patents

Abstract

PURPOSE:To make the voltage generated from and applied across the unit length of a discharge tube equal to or higher than ionization potential so that the discharge tube can discharge easily by providing spiral auxiliary electrodes the winding pitches of which are closer than those of spiral main electrodes. CONSTITUTION:This CO2 gas laser device is constituted of a high-frequency power source 1 for generating a high-frequency output, discharge tube 2, main electrodes 3 and 4 spirally wound around the tube 2, and auxiliary electrodes 5 and 6 spirally wound around the tube 2. When the voltage generated by the electric power supplied from the power source 1 exceeds the ionization potential required for the unit length of the tube 2, auxiliary discharge is produced between the auxiliary electrodes 5 and 6 or volumetric discharge is produced by means of the winding pitches of the electrodes 5 and 6. The auxiliary discharge shifts to the main discharge by means of the main electrodes 3 and 4. Therefore, the discharge tube is surely made to ignite.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high frequency excited C02 gas laser device, and more particularly to an electrode shape for a discharge tube that allows the discharge tube to be ignited inexpensively and reliably.

Prior Art 1, Name of the Invention High-frequency discharge excited C02 gas laser device 2, Claims (1) A C02 gas laser in which high-frequency output is injected into a discharge tube and laser light is generated from gas excited by the high-frequency discharge. The device includes a high-frequency power source that generates the high-frequency output, a parallel plate-shaped main electrode or a spiral-shaped main electrode provided on the outer periphery of the discharge tube, and a spiral-shaped main electrode with a denser winding pitch than the spiral-shaped main electrode. and an auxiliary electrode, the high frequency power source is connected to the main electrode, and the auxiliary electrode is connected to the main electrode, so that an auxiliary discharge occurs between the auxiliary electrodes in addition to the main discharge between the main electrodes. 3. A high frequency discharge excited CO2 gas laser device characterized by the following.

(2) The material of the auxiliary electrode is metal or dielectric,
Also, a patent claim characterized in that the electrode is provided with a metal or dielectric protrusion as the electrode shape. Conventionally, RF excitation is a method in which high-frequency output is injected into a discharge tube and laser light is generated from gas excited by the high-frequency discharge. Regarding ignition of the discharge tube of a CO2 gas laser device, the discharge starting voltage is as low as 100% compared to a DC-excited CO2 gas laser device that applies high DC voltage, making it easier to ignite.However, variations in the discharge starting voltage itself and gas flow rate There were cases where the laser did not ignite due to fluctuations in the discharge tube, dirt on the discharge tube, etc. This was especially likely to occur when the power was reduced using the laser power control, and this caused problems such as processing defects at the processing start point during sheet metal processing.

In order to solve these problems, an auxiliary electrode for pre-ionization is provided separately from the main electrode, and the output of an RF power source that is different from the output of the RF power source that is supplied to the main electrode is supplied to this auxiliary electrode.
Some were made to ignite.

Problem to be Solved by the Invention The auxiliary electrode has a different R from the RF main electrode output that is supplied to the main electrode.
The method of supplying the output of the F power source required two types of RF power sources, making the device expensive.

The present invention eliminates the conventional drawbacks and supplies high RF power to the auxiliary electrode using only the output of the RF power supply supplied to the existing main electrode,
This is intended to ensure the ignition of the discharge tube.

Means for Solving the Problems In order to solve the above problems, the high frequency discharge excitation CO of the present invention
A two-gas laser device has a high-frequency power source that generates high-frequency output, a parallel plate-shaped main electrode or a spiral-shaped main electrode provided on the outer periphery of the discharge tube, and a spiral-shaped main electrode with a denser winding pitch than the spiral-shaped main electrode. an auxiliary electrode, the high frequency power source is connected to the main electrode,
The auxiliary electrode is connected to the main electrode.

In addition, a metal or dielectric bottle electrode is provided as an auxiliary electrode within the inner diameter of one or more discharge tubes, and the main electrode and the auxiliary electrode are connected directly or the main electrode is connected to a specific impedance. The impedance is connected to an auxiliary electrode.

Effect In the above means, by providing a spiral-shaped auxiliary electrode with a denser winding pitch than the spiral-shaped main electrode, the voltage generated and applied per unit length of the discharge tube becomes equal to or higher than the ionization voltage. , easily discharge. Discharging is also facilitated by the provision of metal or dielectric bottle electrodes disposed within one or more discharge tube inner diameters. Moreover, both require only the output of the RF power supply supplied to the main electrode.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to FIGS. 1 to 3.

In FIG. 1, 1 is a high frequency power source that generates high frequency output, and 2 is a discharge tube. A rear mirror and an output mirror (not shown) are provided at both ends of the discharge tube 2, and CO2, He
, No., etc. are introduced and circulated. 3.4 is a main electrode spirally wound around the outer periphery of the discharge tube 2, and is connected to the high frequency power source 1. 6.6 is discharge tube 2
The auxiliary electrode is spirally wound around the outer periphery of the main electrode 3.4, is wound more densely than the main electrode 3.4, is narrower and shorter, and is connected to the main electrode 3.4.

In the above configuration, when the voltage generated by the power injected by the high frequency power supply 1 exceeds the ionization voltage required per unit length of the discharge tube 20, an auxiliary discharge occurs between the auxiliary electrodes 5 and 6. Alternatively, volumetric discharge occurs depending on the winding pitch. When the auxiliary discharge occurs, it shifts to the main discharge by the main electrode 3.4.

FIG. 2 shows another embodiment of the invention, in which a parallel plate-shaped main electrode 7.8 is used instead of the spiral-shaped main electrode 3.4 of FIG.
It has been established.

FIG. 3 shows still another embodiment of the present invention, in which a bottle-shaped auxiliary electrode 9 is provided in place of the spiral-shaped auxiliary electrode 5 in FIG. It is connected to the main electrode 7 via a fixed impedance 1o. ! In addition, the main electrode 8 is extended to a position opposite to the auxiliary electrode 9.

In FIGS. 1 to 3, the main discharge direction by the main electrode is indicated by arrows 11, 12.13, and the auxiliary discharge direction by the auxiliary electrode is indicated by arrow 14.15.degree. 16.

Further, in FIGS. 1 and 2, the auxiliary electrode 6.6 is wound with several turns, but it may be wound with one turn.

Further, the material of the auxiliary electrodes 5, 8.9 may be metal or dielectric. Alternatively, the electrode may be provided with a metal or dielectric protrusion. Furthermore, the outer circumference of the auxiliary electrode 6.6 is covered with an insulating material, and the auxiliary electrode 6.6 is auxiliary! Discharge, sparks, and leaks at the extreme surface may be prevented.

Further, in FIG. 3, one or more bottle-shaped auxiliary electrodes 9 may be provided.

Further, in the configuration shown in FIG. 2, a ring-shaped electrode may be used instead of the auxiliary electrode 5.6.

Effects of the Invention As described above, according to the present invention, there is no need for a separate high-frequency power source for auxiliary discharge, resulting in low cost. Further, by forming the auxiliary electrode in a spiral shape, the auxiliary discharge can be made to be close to a volumetric discharge.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are circuit diagrams of a high-frequency discharge-excited CO2 gas laser device showing an embodiment of the present invention, respectively. 1...High frequency power supply, 2...Discharge tube, 3
,4,7゜8... Main electrode, 6,6.9...
- Auxiliary electrode, 10...Fixed impedance.

Claims (4)

[Claims] (1) In a CO_2 gas laser device in which high-frequency output is injected into a discharge tube and laser light is generated from gas excited by the high-frequency discharge, a high-frequency power source that generates the high-frequency output and a high-frequency power supply provided on the outer periphery of the discharge tube are provided. a parallel plate-shaped main electrode or a spiral-shaped main electrode,
a spiral-shaped auxiliary electrode whose winding pitch is denser than that of the spiral-shaped main electrode, the high-frequency power source is connected to the main electrode, the auxiliary electrode is connected to the main electrode, and a main discharge occurs between the main electrodes. In addition, a high frequency discharge excited CO_2 gas laser device is characterized in that an auxiliary discharge is generated between the auxiliary electrodes. (2) The material of the auxiliary electrode is metal or dielectric,
The high-frequency discharge-excited CO_2 gas laser device according to claim 1, wherein the electrode is provided with a protrusion made of metal or dielectric material. (3) Claim 1 or 2 characterized in that the outer circumference of the surface of the auxiliary electrode is covered with an insulator.
The high-frequency discharge excited CO_2 gas laser device described in 2. (4) As the auxiliary electrode, one or more metal or dielectric pin electrodes are provided inside the inner diameter of the discharge tube, and the main electrode and the auxiliary electrode are connected directly or the main electrode is connected to a specific impedance. 2. The high-frequency discharge-excited CO_2 gas laser device according to claim 1, wherein a unique impedance and an auxiliary electrode are connected.