JPH1012948A - Axial flow gas laser device and operation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abnormal discharge by providing an auxiliary electrode of a surrounding ring shape connected with the anode of a DC power supply, near the cathode on the outside of a tube portion of discharge means. SOLUTION: An auxiliary electrode 4 of a surrounding ring shape is provided on the outer periphery of a cathode electrode 1 of a T-shaped discharge tube 10, and the auxiliary electrode 4 is connected to a positive side of a DC power supply S to obtain the same potential as an anode 2. The distance L1 between the auxiliary electrode 4 and the cathode 1 is set to be shorter than the distance L2 between a holding metal fitting 18 of a reflection block on the side opposite to the cathode 1 and the anode 2. The T-shaped discharge tube 10, an intermediate block, the reflection block and an output block constitute discharge means. At the start of discharge, the discharge resistance from the anode 2 to the cathode 1 may be apparently made smaller than the gas impedance between the anode 2 and the holding metal fitting 18 of the reflection block on the side of a mirror 3. Therefore, discharge from the anode 2 to the cathode 1 may be securely carried out, thereby preventing abnormal discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, 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. The 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 disposed, 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 Laid-Open Publication No. Hei 1-103889 discloses that a laser gas is supplied into a discharge tube 51 and at least a pair of main electrodes 52 and 5 are supplied into the discharge tube 51 as shown in FIG.
3, the main electrodes 52 and 53 are connected to the DC circuit 54, the voltage of the DC circuit 54 is applied between the main electrodes 52 and 53, and a glow discharge is generated between the main electrodes 52 and 53, and the glow discharge is performed. In a device that excites a laser gas and generates a laser beam, an auxiliary electrode 55 is provided outside the one main electrode side 52, specifically, outside the discharge tube 51 on the anode side, and the auxiliary electrode 55 is connected to the other main electrode 53. Specifically, the gas laser generator 5 is connected to the same potential as the cathode.
0 has been proposed.

However, in the gas laser generator 50 according to JP-A-1-103889, since the auxiliary electrode 55 has the same potential as the cathode 53, the discharge from the anode 52 in the opposite direction to the cathode 53 is performed. So-called abnormal discharge is not prevented.

[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 are held by a grounded holding fitting. It is an object of the present invention to provide a gas laser device in which abnormal discharge is eliminated and a method of operating the gas laser device.

[0007]

The gas laser apparatus according to the present invention has an axial flow in which a required number of discharge means having a tubular portion on one side and a mirror on the other side are optically connected in series. In the type gas laser device, an auxiliary electrode connected to an anode of a DC power supply is provided in a circular shape near the cathode outside the tubular portion of each discharge means.

In the gas laser device according to the present invention, when the discharging means is held by a holding member, the distance between the auxiliary electrode and the cathode is set to a distance between the holding member and the anode provided on the side opposite to the cathode with respect to the anode. It is preferable that the distance be shorter than the distance.

In the gas laser device according to the present invention, a power supply for the auxiliary electrode may be provided independently of a power supply for the anode.

On the other hand, in the operation method of the axial flow type gas laser device of the present invention, a cathode is provided on one side having a tubular portion,
A method for operating an axial-flow gas laser apparatus comprising a mirror provided on the other side and a required number of optically connected discharge means having auxiliary electrodes connected to a power supply independent of a power supply of an anode in series. It is characterized in that the electrode power is turned on only for a short time immediately after the start of discharge.

[0011]

Since the axial flow type gas laser device of the present invention is constructed as described above, the discharge is initially performed between the auxiliary electrode and the cathode. Since the gas impedance between the anode and the cathode is reduced by the discharge, the discharge between the anode and the cathode is smoothly performed.

In the case where the power supply to the auxiliary electrode is provided independently, the power supply of the auxiliary electrode is turned on only for a short time immediately after the start of the discharge, so that the provision of the auxiliary electrode adversely affects the discharge. Is eliminated.

[0013]

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.

Embodiment 1 FIG. 1 is a schematic diagram of an axial flow type gas laser device L according to Embodiment 1 of the present invention, and FIG. 2 is a simplified circuit diagram thereof. Gas laser device L 'shown in FIG.
The auxiliary electrode 4 is provided in a circular shape around the cathode 1 side of the T-shaped discharge tube 10, and the auxiliary electrode 4 is connected to the positive side of the DC power source S to connect the anode 2 to the anode 2. It is the same potential. In this case, the auxiliary electrode 4 and the cathode 1 a distance L ₁ between the distance from the cathode 1 and the holding member 18 and the anode 2 on the opposite side of the reflection block 14 L ₂
It has been shorter. For example, anode 2 and cathode 1
Of the reflection block 14 is 300 mm.
If the distance L ₂ between the anode 8 and the anode 2 is 140 mm, the distance L ₁ between the auxiliary electrode 4 and the cathode ₁ is, for example, 1
35 mm. 1 and 2, the same or similar elements as those in FIG. 6 are denoted by the same reference numerals. In the first embodiment, a discharge means is formed by the T-shaped discharge tube 10, the intermediate block 12, the reflection block 14, and the output block 16.

By setting the auxiliary electrode 4 at such a position, the discharge resistance (gas impedance) apparently from the anode 2 to the cathode 1 at the start of the discharge is reduced from the anode 2 to the holder 1 of the reflection block 14 on the mirror 3 side.
8, the discharge can be reliably performed from the anode 2 to the cathode 1, thereby preventing abnormal discharge.

The auxiliary electrode 4 is attached to the discharge tube 10 by winding a ribbon-shaped thin copper plate 4a around the outside of the glass discharge tube 10 as shown in FIG. 4b. Therefore, a kind of capacitor is formed between the auxiliary electrode 4 and the cathode 1.

Next, the operation of the gas laser apparatus having such a configuration will be described with reference to FIGS.

(1) When the switch 5 is turned on, a current i ₁ flows from the auxiliary electrode 4 to the cathode 1 at that moment. As described above, since the auxiliary electrode 4 and the cathode 1 form a kind of capacitor, as shown in FIG.
The current i ₁ from the auxiliary electrode 4 to the cathode 1 rapidly increases, but after reaching the maximum value, rapidly decreases and disappears.

(2) When the current i ₁ from the auxiliary electrode 4 to the cathode 1 reaches the maximum value, the resistance between the anode 2 and the cathode 1 in the discharge tube 10 is reduced. so as to be induced to the current i _1, a current i ₂ begins to flow from the anode 2 to the cathode 1 (FIG. 3
(See (b) and (c)).

[0020] (3) a current i ₂ from the anode 2 to the cathode 1 leads to a steady state through a transient state corresponding to the transient state of the applied voltage V (FIG. 3 (a), (b) refer).

As described above, according to the first embodiment,
An auxiliary electrode 4 is provided around the outer periphery of the discharge tube 10 in a circular shape. At the start, a discharge is caused between the auxiliary electrode 4 and the cathode 1, and then the anode 2 is induced by the discharge between the auxiliary electrode 4 and the cathode 1. The discharge between the anode 2 and the cathode 1 prevents discharge from the anode 2 to the holding fitting 18 and the mirror 3 on the opposite side of the cathode 1, that is, abnormal discharge. For this reason, performance deterioration of the processing machine and damage to components due to abnormal discharge are prevented. Further, since abnormal discharge is eliminated, energy loss is also eliminated.

Embodiment 2 An axial gas laser device L1 according to Embodiment 2 of the present invention.
FIG. 4 shows a schematic diagram of the axial flow type gas laser device L1.
Is a modification of the axial flow type gas laser device L of the first embodiment, in which a power source (auxiliary electrode power source) S ₂ is provided independently of the main power source S ₁ between the anode 2 and the cathode 1 for the auxiliary electrode 4. It is. The auxiliary electrode power supply S _2, as shown in FIG. 6, the main power supply S ₁ at the same time on and the discharge between the anode 2 and the cathode 1 is controlled to be off when stabilized. That is, it is controlled to be turned on only for a short time immediately after the start of discharge. In FIG. 5,
The solid line indicates the anode voltage, and the dotted line indicates the auxiliary electrode voltage.

As described above, in the second embodiment, the power is supplied between the auxiliary electrode 4 and the cathode 1 only for a short time immediately after the start of discharge by the auxiliary electrode power supply S _2. Similarly, a stable discharge is achieved, and the effect on the discharge of the auxiliary electrode 4 after the start of the discharge can be eliminated, which is an effect not found in the first embodiment.

[0024]

As described in detail above, in the present invention, a shaft is formed by optically serially connecting a required number of discharge units each having a tubular portion provided with a cathode on one side and a mirror on the other side. In a flow-type gas laser device, an auxiliary electrode is provided in a circular shape so as to form a kind of capacitor with the cathode on the outer periphery of the tubular portion. Since the discharge of the cathode is performed, the discharge from the anode to the holding member or the mirror on the opposite side of the cathode, that is, an excellent effect of preventing abnormal discharge is obtained. As a result, the effect that the processing performance in the laser processing machine is improved can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a discharge tube of an axial flow gas laser device according to a first embodiment of the present invention.

FIG. 2 is a simplified circuit diagram of the discharge tube.

3A and 3B are graphs showing characteristics of the discharge tube, wherein FIG. 3A shows a voltage waveform, FIG. 3B shows a current between an anode and a cathode, and FIG. 3C shows a current between an auxiliary electrode and a cathode. Is shown.

FIG. 4 is a schematic diagram of an axial-flow gas laser device according to a second embodiment of the present invention.

FIG. 5 is a graph showing a waveform of a voltage applied to a discharge tube in the device.

FIG. 6 is a schematic view of a conventional axial flow type gas laser device.

FIG. 7 is a sectional view showing the vicinity of a reflection block portion of the device.

FIG. 8 is a sectional view of the vicinity of an intermediate block portion of the device.

FIG. 9 is a schematic diagram of a gas laser device according to the proposal of Japanese Patent Application Laid-Open No. 1-103889.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cathode 2 Anode 3 Mirror 4 Auxiliary electrode 4a Copper plate 4b Fixing member 5 Switch 10 Discharge tube 12 Intermediate block 14 Reflection block 16 Output block 18 Holder L Gas laser device S Power supply

Claims (4)

[Claims] 1. An axial flow gas laser apparatus comprising a tubular portion having a cathode provided on one side and a mirror provided on the other side in a required number of optically serially connected manners. An axial-flow gas laser device comprising: an auxiliary electrode connected to an anode of a DC power supply in a circular shape near an outer cathode. 2. The discharge means is held by a holding member, and a distance between the auxiliary electrode and the cathode is shorter than a distance between the holding member provided on the opposite side of the anode to the cathode and the anode. The axial flow type gas laser device according to claim 1, wherein: 3. The axial flow gas laser device according to claim 1, wherein a power supply for the auxiliary electrode is provided independently of a power supply for the anode. 4. A required number of discharge means having an auxiliary electrode connected to a power supply independent of an anode power supply, wherein a cathode is provided on one side having a tubular portion and a mirror is provided on the other side. A method for operating an axial flow gas laser device comprising: turning on a power supply of an auxiliary electrode for a short time immediately after the start of discharge;