JPH1079540A - Axial flow-type gas laser device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a gas laser device which is kept free from abnormal discharges by a method, wherein a main discharge and an auxiliary discharge are made to occur, overlapping with each other for a prescribed time. SOLUTION: A gas laser device L is equipped with a main discharge power supply SM for a main discharge, a simmer discharge power supply SS for a simmer discharge (auxiliary discharge), a main discharge power supply pulse-generating circuit CM, pulse-generating circuit CS for a simmer discharge power supply, and a pulse timing circuit CT which regulates the pulse-generating circuits CM and CS as to their pulse- generating timings. The simmer discharge power supply SS is turned on just before a main discharge is finished, and the simmer discharge power supply SS is so controlled as to be turned off just after a main discharge starts. Therefore, a discharge tube 10 is lessened in gas resistance due to the negative-resistance characteristic of gas which is filled in the discharge tube 10 at a time when the main discharge takes place, so that a main discharge takes place smoothly, and an abnormal discharge is prevented. As the simmer discharge power supply SS is turned off or on just after a main discharge starts or just before a main discharge stops, the adverse effects from a simmer discharge on a laser output is limited to a minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for an axial gas laser apparatus and an axial gas laser apparatus. More specifically, the present invention relates to a control method for preventing abnormal discharge in an axial flow gas laser apparatus in which discharge means having a required number of tubular portions are optically connected in series, and an axial flow gas laser apparatus.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a modified T-shaped discharge tube 10 having a cathode 1 at one end and an anode 2 at a protruding portion at the center is provided.
There is known an axial flow type gas laser device (hereinafter simply referred to as a gas laser device unless otherwise misunderstood) L 'which generates a high output gas laser by optically connecting a required number of optically in series. This gas laser device L 'has a structure in which a required number of discharge tubes 10, 10, 10,... Must be arranged in a limited space, and as shown in FIGS. An intermediate block 12 on which the mirrors 1 and 1 are mounted is arranged, a discharge tube 10 is mounted on each cathode 1 of the intermediate block 12, and a reflection block 14 on which a mirror 3 is mounted on the other end of the discharge tube 10 is mounted. The required number of discharge tubes 1 is
Are arranged in parallel, the laser light is turned back at one end of the discharge tube 10 and introduced into the next discharge tube 10, and the energy is thus increased. The emitted laser light is emitted by an output block 16 mounted on the output end of the discharge tube 10 at the last stage.

However, in this gas laser device L ', the discharge tubes 10, 10, 1 arranged in parallel are arranged.
, 0,..., And the output block 16 must be held in a predetermined positional relationship, so that the reflection blocks 14, 14 and the reflection block 14 and the output block 16 are Is held by And, in order to prevent an electric shock accident due to the holding fitting 18 and the mirror 3, the holding fitting 18 and the mirror 3 are grounded. Therefore, the anode 2
From the anode 1 to the mirror 3 or the holding metal member 18 on the opposite side of the cathode 1 in some cases. So-called abnormal discharge may occur. Therefore, in the conventional gas laser device L ', there is a problem that the discharge is unstable, and thus the performance of the processing machine is deteriorated and parts are damaged, and also that the energy efficiency is deteriorated.

Japanese Patent Application Laid-Open No. 63-233580 discloses a gas laser oscillation method capable of oscillating a pulsed gas laser beam with a small size and high efficiency. In a gas laser oscillation method of oscillating pulse gas laser light from a discharge tube having a main discharge electrode, an auxiliary discharge current having a small current value and being discontinuous is supplied between discharge electrodes of the discharge tube, and immediately thereafter, the auxiliary discharge current is supplied to the auxiliary discharge current. Subsequently, a gas laser oscillation method has been proposed in which a main discharge current having a large current value is supplied to oscillate pulse gas laser light having a high peak energy.

However, Japanese Patent Application Laid-Open No. 63-233580
In the gas laser oscillation method according to the proposal of Japanese Patent Application Laid-Open No. H11-157, an auxiliary discharge current having a small and discontinuous current value is supplied between the discharge electrodes of the discharge tube, and immediately after the auxiliary discharge current, a main current having a large current value is supplied. Since a pulse gas laser beam with a high peak energy is supplied by supplying a discharge current, an abnormal discharge may occur when the main discharge is completed and the next auxiliary discharge is performed. Because there is a vacuum tube circuit for turning on and off the anode, a high voltage is always applied to the anode, and when the main discharge and the auxiliary discharge are turned off, abnormal discharge from the anode to the mirror or the holding bracket may occur. Therefore, it cannot be directly applied to the gas laser oscillation method or the control method of the gas laser device L ′ having the above configuration.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and is directed to a gas laser apparatus in which a required number of discharge means having a tubular portion is held by a grounded holding fitting. It is an object of the present invention to provide a method of controlling a gas laser device in which abnormal discharge is eliminated and a gas laser device.

[0007]

According to the present invention, there is provided a method for controlling an axial flow gas laser apparatus, comprising a main discharge power supply and an auxiliary discharge power supply for discharging a weak current, and a discharge means having a required number of tubular portions. A method of controlling an axial-flow gas laser device held by a grounded metal fitting, wherein a switching time between a main discharge and an auxiliary discharge is overlapped for a predetermined time.

In the method for controlling an axial flow type gas laser device according to the present invention, for example, the predetermined time is set to about 0.05 millisecond.

On the other hand, the axial flow type gas laser device of the present invention
A main discharge power supply, an auxiliary discharge power supply for discharging a weak current,
A pulse generator for the main discharge power supply, a pulse generator for the auxiliary discharge power supply, and a timing adjustment means for adjusting the timing of the pulse generation of the two pulse generation means, and a discharge means having a required number of tubular portions is grounded. It is characterized by being held by a holding metal fitting.

[0010]

In the axial-flow gas laser device according to the present invention, the main discharge and the auxiliary discharge are overlapped for a predetermined period of time.
Abnormal discharge is prevented. Therefore, a stable laser output is obtained, and the processing quality is improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments with reference to the accompanying drawings, but the present invention is not limited to only such embodiments. In FIG. 1, the same or similar components as those in FIG. 5 are denoted by the same reference numerals.

FIG. 1 is a schematic diagram of a gas laser apparatus L to which the control method of the present invention is applied. This gas laser device L
Is, there is an improvement of the conventional gas laser apparatus L'shown in FIG. 5, as shown in FIG. 1, a main discharge power supply for forming a main discharge (MPSU) and S _M, in order to prevent abnormal discharge A simmer discharge power supply (SP) that performs simmer discharge (auxiliary discharge)
SU) S _S , a main discharge power supply pulse generation circuit C _M , a simmer discharge power supply pulse generation circuit C _S, and a pulse timing circuit C _T for adjusting the timing of pulse generation in both pulse generation circuits. as well as on the simmer discharge power S _S to the main discharge terminates immediately before as shown in 2, it is made by controlling to turn off the simmer discharge power S _S immediately next main discharge start. That is, the main discharge and the simmer discharge slightly overlap each other.

By switching the main discharge power supply S _M and the simmer discharge power supply S _S in such a relationship, the gas resistance in the discharge tube 10 is reduced due to the negative resistance characteristics of the gas in the discharge tube 10 at the time of the main discharge. As a result, the main discharge is made smooth and abnormal discharge is prevented (see FIGS. 3 and 4). Further, since the off or on the simmer discharge power S _S main discharge starts immediately after or immediately before the end, adverse effects on the laser output due to simmer discharge is minimized.

[0014] on in this case, the simmer discharge power supply S _S is,
Is preferably made to the end close as 0.05 msec before the main discharge, also off the simmer discharge power supply S _S is preferably made after about after starting the main discharge 0.05 msec. By the simmer discharge power S _S switching between the main discharge power supply S _M Thus, the duty ratio of 50% is achieved at a frequency 1 kHz. Therefore, good laser light can be obtained, and the processing quality is improved. It is not preferable that both discharges are overlapped more than this because adverse effects due to simmer discharge appear, and shorter than this is not preferable because abnormal discharge may occur.

[0015]

As described in detail above, according to the present invention,
An excellent effect of preventing abnormal discharge in the discharge tube without substantially affecting the laser output can be obtained. Therefore, an excellent effect of stabilizing the laser beam and improving the processing quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of an axial flow type gas laser device of the present invention.

FIG. 2 is a timing chart of simmer discharge and main discharge.

FIG. 3 is a schematic diagram of a cathode current in a coaxial flow type gas laser device.

FIG. 4 is a schematic diagram of an anode voltage in a coaxial flow type gas laser device.

FIG. 5 is a schematic view of a conventional axial flow laser device.

FIG. 6 is a sectional view showing the vicinity of a reflection block portion of the device.

FIG. 7 is a sectional view of the vicinity of an intermediate block portion of the device.

[Explanation of symbols]

1 cathode 2 anode 3 mirror 10 the discharge tube 18 held fitting L gas laser apparatus S _M main discharge power supply S _S simmer discharge power supply C _M main discharge power supply for the pulse generating circuit C _S simmer discharge power source pulse generator circuit C _T pulse timing circuit

Claims (3)

[Claims] 1. An axial flow gas laser apparatus comprising: a main discharge power supply; and an auxiliary discharge power supply for discharging a weak current, wherein a discharge means having a required number of tubular portions is held by a grounded holding fitting. A method of controlling an axial flow gas laser device, wherein a switching time between a main discharge and an auxiliary discharge is overlapped for a predetermined time. 2. The method according to claim 1, wherein the predetermined time is about 0.05 millisecond. 3. A main discharge power supply, an auxiliary discharge power supply for discharging a weak current, a pulse generator for the main discharge power supply, a pulse generation means for the auxiliary discharge power supply, and a timing for generating pulses of the two pulse generation means. An axial flow gas laser apparatus comprising: a timing adjusting means for adjusting; and a discharge means having a required number of tubular portions held by a grounded metal fitting.