JPH01103889A - Gas laser generating device - 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 [Field of Industrial Application] The present invention relates to a gas laser generator with an improved auxiliary electrode.

[Conventional technology]

In order to increase the output of the gas laser generator, the gas pressure within the discharge tube is increased.

On the other hand, since the discharge starting voltage increases when the gas pressure increases, in order to start the discharge smoothly, a method has been proposed in which an auxiliary electrode is installed inside the discharge tube and a voltage is applied from the outside (for example, (Sho 60-161687).

Conventional gas laser generators are shown in Figures 4, 5 (A), and (
This will be explained using B) and (C). When the switch 22 is turned on, the DC power supply 21 is connected between the main electrodes 2 and 3 in the discharge tube 1 and between the main electrode 2 and the auxiliary electrode 30, and the discharge power supply voltage V of the DC power supply is applied. A glow discharge current 11 and an auxiliary current 12 flow. Changes in the relationship between the discharge power supply voltage V, the glow discharge current 11, the auxiliary current 12, and the time t are shown in the characteristic diagrams shown in FIGS. 5(A) to 5(C).

As shown in FIG. 5(A), the discharge power supply voltage {circle around (2)} is high at the start of discharge and becomes constant as time t elapses after the start of discharge, so that the glow discharge current 11 also becomes as shown in FIG. 5(B). The glow discharge current 11 is constant except at the start of discharge. At the start of discharge, the auxiliary current 12 increases rapidly, as shown in FIG. 3(C), and after the start of discharge, it becomes constant as time t passes.

[Problem that the invention seeks to solve]

In this way, in the conventional example, the auxiliary electrode 3 is placed inside the discharge tube.
Since glow discharge is maintained at the auxiliary electrode 30 even after the discharge has started, the auxiliary current 12 continues to flow, and a resistor 31 is required to regulate this current value. The heat generated by the resistor 31 causes thermal loss. Further, there are drawbacks such as contamination of the inside of the discharge tube due to wear and tear of the auxiliary electrode 30 and a complicated structure due to the installation of the auxiliary electrode 30 inside the discharge tube.

By the way, roughly estimating the heat generated in the above resistance, in a 500W class oscillator using four discharge tubes, the current regulating resistance of the auxiliary electrode is about 2MΩ, and the discharge sustaining voltage is 12kV, so the amount of heat generated is 288W. It can be seen that more than half of the heat of the oscillation output is released as loss.

An object of the present invention is to provide a gas laser generator that reduces power consumption by flowing an auxiliary current between a main electrode and an auxiliary electrode only at the start of discharge.

[Means for solving problems]

A main electrode and an auxiliary electrode on one of the inside and outside of the discharge tube are arranged to face each other, and the auxiliary electrode is connected to the other main electrode so as to have the same potential.

[Effect]

The discharge power supply voltage V before the start of glow discharge rapidly increases to the maximum value of the charging voltage, so the voltage change over time (
dv/dt) is large, but once the discharge starts, it becomes a constant voltage value of glow discharge, so dv/dt becomes a small value. The auxiliary electrode and the main electrode are separated by the wall of the discharge tube, and the impedance between them is capacitance, so that the auxiliary current is supplied only when dv/dt is large.

〔Example〕

An embodiment of the present invention is shown in FIG. 1 and will be described below.

FIG. 1 shows an example in which discharge tubes 1 are connected in a two-sided row.

The laser gas 12A supplied from the supply pipe 12 passes through the discharge tube 1 and is discharged from the exhaust pipe 13, and is supplied to the supply pipe 12 again by a gas circulation device and a cooling device (not shown). Discharge tube 1 is glass.

It is formed of an insulator such as ceramics, and main electrodes 2 and 3 on the anode side and the cathode side are provided inside. A DC power supply 21 is connected between the main electrodes 2 and 3,
The laser gas 12A excited by the discharge causes laser oscillation between the output mirror 5 and the total reflection mirror 6, and external laser light 7 is generated.
is released.

An auxiliary electrode 4 consisting of a ring formed in the shape of a conductor is installed on the outside of the discharge tube on the side of one of the main electrodes.

The auxiliary electrode 4 is electrically connected to the other main electrode 3 at the same potential.

Next, when the switch 22 is turned on and the discharge power supply voltage V of the DC power supply 21 is applied between the main electrodes 2 and 3 and between the main electrode 2 and the auxiliary electrode 4, as shown in FIG. In Figure (B), the same discharge power supply voltage ■ and glow discharge current 11 as in Figures 5 (A) and (B) flow, but at the start of glow discharge, the auxiliary current 12 shown in Figure 5 (C) flows. flows. Auxiliary current 1
No. 2 flows rapidly at the start of mold release, but does not flow after the start of discharge. The reason for this is that the main electrode 2 and the auxiliary electrode 4 are partitioned by the wall of the discharge tube 1, and the impedance between them is capacitance. The auxiliary current 12 flows only when the change (dv/dt) is large. In other words, it flows only when the auxiliary current 12 is large, and does not flow when the auxiliary current 12 is small. Auxiliary current 12
When the auxiliary current 12 is small, the insulator (dielectric constant 1) of the discharge tube 1 blocks the flow of the auxiliary current 12.

〔Effect of the invention〕

As a result, according to the embodiment of the present invention, there is no need for an auxiliary current control resistor, which was necessary in the past, and there is no heat loss caused by the resistor, reducing the amount of power required for laser oscillation. I can draw. In addition, since the auxiliary electrode is installed outside the discharge tube, there is no need for contamination in the oscillator due to electrode consumption, and there is no need to replace the electrode, resulting in improved reliability.

In addition, when oscillating with a high pulse peak in a short period of time by pulse discharge, it is necessary to supply current to the laser gas within a short period of time. In such cases, a steeper current supply can be performed, so that the discharge rises more quickly and even more effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a gas laser generator according to an embodiment of the present invention, FIG. 2 is a schematic explanatory diagram of FIG. 1, and FIG. 3 (A)
or B) are characteristic diagrams of FIGS. 1 and 2, FIG. 4 is a schematic explanatory diagram of a conventional gas laser generator, and FIGS. 5(A) to C) are characteristic diagrams of FIG. 4. DESCRIPTION OF SYMBOLS 1...Discharge tube, 2 and 3...Main electrodes on anode and cathode sides, 4...Auxiliary electrode.

Claims (1)

[Claims] 1. Supply laser gas into the discharge tube, place at least one pair of main electrodes inside the discharge tube, connect the main electrodes to a DC circuit, apply the voltage of the DC circuit between the main electrodes, and generate a glow discharge between the main electrodes. The device excites laser gas by glow discharge to generate laser light, characterized in that an auxiliary electrode is provided outside the discharge tube on the side of one of the main electrodes, and the auxiliary electrode is connected to the same potential as the main electrode on the other side. Gas laser generator.