JPH07162061A - Gas laser - Google Patents

Abstract

PURPOSE:To surely amplify laser light by using a plurality of main discharge means arranged in series. CONSTITUTION:The title gas laser consists of the following; a laser tube 1 in which gas laser medium is contained, a main discharge means wherein a plurality of main discharge parts 2, 3 in which cathodes 4 and anodes 5 are isolated and made to face to each other are arranged in series, a high voltage power supply 8 which applies a high voltage across the cathode 4 and the anode 5 of each of the main discharge parts 2, 3, and ignites main discharge in discharge spaces 2A, 3A between the electrodes, preliminary ionization means 11, 12, and an upper trigger pin electrode 22 and a lower trigger pin electrode 23 which are arranged between the adjacent end portions of the main discharge parts 2, 3 and make a pair. In the ionization means, an upper preliminary pin electrode 13 and a lower preliminary pin electrode 14 whose tips are made to face each other via a specified gap make a pair. A plurality of the pin electrode pairs are arranged at specified intervals on the side of the electrodes of the main discharge parts 2, 3, and preliminarily ionize the discharge spaces 2A, 3A prior to the main discharge in the main discharge parts 2, 4. A trigger means 21 is set in the state that discharge is generated more easily than the preliminary discharge means 11, 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device which excites a gas laser medium by discharge to generate laser light.

[0002]

_2. Description of the Related Art Generally, in a gas laser device such as a TEACO ₂ laser or an excimer laser, a cathode and an anode constituting a main discharge portion are separated and face _each other in a laser tube containing a gas laser medium. The gas laser medium is discharge-excited to emit laser light by generating a main discharge in the discharge space between them.

Preliminarily ionizing means for preionizing the discharge space portion is provided on the side of the main electrode in order to facilitate ignition of the main discharge to the main electrode. In this preionization means, the upper pin electrode and the lower pin electrode, which form a pair with their tips separated and opposed at a predetermined gap,
It is arranged at a predetermined interval.

By the way, in order to increase the output of the gas laser device, a plurality of sets of main discharge parts having the above-mentioned structure, for example, two sets of main discharge parts are arranged in series, and the amplification action of each main discharge part is performed. A so-called multi-stage gas laser device for obtaining high-power laser light is used. In that case, of course, a preliminary ionization means is provided beside each main discharge part.

In the multistage gas laser device having such a structure, the gaps between the tips of the upper pin electrodes and the lower pin electrodes of the plurality of sets of the respective preionization means are set to be constant. However, the plurality of sets of preionization pin electrodes are not ignited at the same time under various conditions during discharge, and when any one set of pin electrodes is ignited, the spark discharge is generated. The electrons generated by the light continuously ignite the discharge of the other set of preionization pin electrodes.

Therefore, for each preionization, there is a time lag until the discharge is ignited in all the sets of preionization pin electrodes, and the spark discharge is also ignited at the first position. The timing waveforms of the pre-ionization of the pair of pre-ionization means are deviated as shown by solid lines and broken _lines in FIGS. 7A and 7B, and as a result, as shown by T _j1 in FIG. , Jitter of about 30 ns occurs.

[0007] From the discharge space portion is pre-ionization, the time to the main discharge is ignited, for example because it is almost constant at about 100 ns, the jitter of T _j1 to preionization discharge - the results, the preliminary Jitter indicated by T _j2 in the figure also occurs at the timing of the main discharge depending on the ionization discharge.

Jitter-width T _j1 of such preionization discharge
And the jitter width T _j2 of the main discharge is generated between the two main discharge portions. The jitter width between the two main discharge parts is
The preionization discharges of the pair of preionization means are different depending on which position of the preionization pin electrode is first ignited, and the first ignition is also different for each discharge.

As described above, when the timings of the main discharges of the two main discharge parts are deviated, the two main discharge parts operate separately, so that the amplifying action in each main discharge part is lost and -The light output cannot be increased.

[0010]

As described above, when a plurality of main discharge parts are arranged in series, the preionization means of the preionization means provided in each main discharge part causes a jitter, and the jitter causes the main ionization. Since the jitter also occurs in the discharge, the timing of the main discharge of the plurality of main discharge parts is deviated, and the amplifying action may be lost due to the deviation.

The present invention has been made in view of the above circumstances. An object of the present invention is to prevent the discharges generated by the respective preionization means provided in the plurality of main discharge parts from jittering.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas laser device in which the occurrence of the above is prevented and the timing of the main discharge in the plurality of main discharge parts is not shifted.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is a gas laser apparatus for generating laser light by exciting a gas laser medium by electric discharge, in which the gas laser medium is housed. A laser tube, and a main discharge means in which a plurality of main discharge parts in which the cathode and the anode are spaced apart and opposed to each other are arranged in series,
A high voltage power supply for applying a high voltage to the cathode and the anode of each of the main discharge parts to ignite the main discharge in the discharge space between these electrodes,
An upper spare pin electrode and a lower spare pin electrode whose tips are opposed to each other through a predetermined gap form a pair, and a plurality of pin electrode pairs are arranged laterally of the electrodes of the main discharge unit at predetermined intervals and the main Pre-ionization means for pre-ionizing the discharge space prior to main discharge in the discharge part, and a pair of upper trigger-pin electrode and lower trigger-pin electrode arranged between adjacent ends of the main discharge part. And a trigger means which is set in a state in which discharge is more likely to occur than the preionization means.

[0013]

According to the above construction, first, the trigger means causes the discharge, and the discharge causes the pair of preionization means located on both sides of the trigger means to generate the discharge to preionize the discharge space. Since the main discharge is ignited in the main discharge part by the preliminary ionization, the timings of the main discharges generated in the plurality of main discharge parts are the same.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a first embodiment of the present invention, and the gas laser apparatus shown in FIG. 1 includes a laser tube 1 in which a gas laser medium is housed. This laser tube 1
Inside, a first main discharge part 2 and a second main discharge part 3 forming a main discharge means are arranged in series. That is, each of the main discharge parts 2 and 3 has a main electrode pair composed of a cathode 4 and an anode 5 which are arranged in parallel and opposed to each other. The pair of anodes 5 are provided in the central portion in the width direction on the lower mounting plate 6. This lower mounting plate 6 is grounded.

The pair of cathodes 4 are electrically connected to and held by the upper mounting plate 7 via the connecting members 7a. Each upper mounting plate 7 is connected to the negative side of the high voltage power source 8. This high-voltage power supply 8 causes the cathode 4 to
When a high voltage is applied between the cathode and the anode 5, the first discharge space portion 2A between these electrodes, that is, the cathode 4 and the anode 5 of the first main discharge portion 2, and the second main A main discharge is ignited in the second discharge space portion 3A between the cathode 4 and the anode 5 of the discharge portion 3 as described later.

The first main discharge section 2 and the second main discharge section 3 described above.
A first preliminary ionization means 11 and a second preliminary ionization means 12 are provided on the sides of the cathode 4 and the anode 5, respectively.
As shown in FIG. 3, each of the preliminary ionization means 11 and 12 has an upper preliminary pin electrode 13 arranged on both sides of the cathode 4 of each of the main discharge portions 2 and 3, and a predetermined lower end surface of the upper preliminary pin electrode 13. The lower preliminary pin electrode 14 is spaced apart and opposed via the gap G ₁ .

The upper auxiliary pin electrode 13 is attached to the upper mounting plate 7 via a peaking capacitor 15, and the lower auxiliary pin electrode 14 is attached to the lower mounting plate 6.

In each of the preliminary ionization means 11 and 12, a spark discharge is ignited between the upper preliminary pin electrode 13 and the lower preliminary pin electrode 14 prior to the main discharge of the cathode 2 and the anode 3, respectively. According to the above, the first and second discharge space portions 2
Pre-ionize A and 3A.

The first main discharge section 2 and the second main discharge section 3
An installation space S is formed between the end portions adjacent to each other, and the trigger means 21 is disposed in this installation space S.
Each of the trigger means 21 has two upper trigger pin electrodes 22 and an upper end surface of the upper trigger pin electrodes 22.
And two lower trigger-pin electrodes 23, which are spaced apart and opposed to the lower end surface of the above through a predetermined gap G ₂ .

The upper trigger pin electrode 22 on one side is connected to the upper mounting plate 7 of the first main discharge section 2 by the peaking capacitor 15.
Attached via the other upper trigger-pin electrode 2
2 is attached to the upper attachment plate 7 of the second main discharge part 3 via a peaking capacitor 15. The two lower trigger-pin electrodes 23 are erected on the lower mounting plate 6.

As shown in FIG. 3, the trigger means 21
Upper trigger pin electrode 22 and lower trigger pin electrode 2
The gap G ₂ with respect to 3 is set smaller than the gap G ₁ between the upper preliminary pin electrode 13 and the lower preliminary pin electrode 14 of the pair of main discharge parts 2 and 3.

As a result, the high-voltage power supply 8 operates and the first
Before the spark discharge is ignited by the preliminary pin electrodes 13 and 14 of the preliminary ionization means 11 and the second preliminary ionization means 12 of
Spark spark discharge is ignited by the trigger pin electrodes 22 and 23 of the trigger means 21. For example, the gap G ₁ is set to about 1.5 mm ～2.0Mm, gap G ₂ is set to 0.5 mm ± 0.3 mm.

A blower 31 for circulating the gas laser medium therein and a heat exchanger 32 for suppressing the temperature rise of the gas laser medium are disposed in the laser tube 1. A high reflection mirror 33a for a resonator and an output mirror 33b for oscillating the laser light L generated in the first and second discharge spaces 2A and 3A are provided on both end surfaces of the laser tube 1. Is provided.

The blower 31 comprises a pair of fans 31a corresponding to the first and second main discharge sections 2 and 3, and a drive source 31b for rotationally driving the fans 31a. Next, the operation of the gas laser device having the above configuration will be described. When the pair of high-voltage power supplies 8 operate, the peaking capacitor 15
Via the upper preliminary pin electrode 13 of the first and second preliminary ionization means 11 and 12 and the upper trigger of the trigger means 21.
A voltage is generated in the pin electrode 22, and when the voltage reaches a predetermined value, spark discharge is ignited.

The spark discharge is generated by the preionization means 11,
The gap G ₂ between the pin electrodes 22 and 23 of the trigger means 21 is larger than the gap G ₁ between the pin electrodes 13 and 14 of 12
Is set to be smaller, the discharge is likely to occur. Therefore, the pin electrodes 22, 23 of the trigger means 21 are
The spark discharge is ignited first in the interval. Since the trigger means 21 has two pairs of pin electrodes on one side in the width direction, either one of the pairs is first ignited by spark discharge (trigger discharge), and at the same time as the other ignition, the spark discharge is triggered. The set is also triggered-discharged.

The time delay of the two sets of trigger discharges of the pin electrodes 22 and 23 of the trigger means 21 is almost zero because the _two pin electrode pairs are adjacent to each other and the gap G ₂ is small. It can be less than or equal to ns.

One set of pin electrodes 2 of the trigger means 21
If 2 and 23 are on the side of the first main discharge unit 2, the trigger-
Due to the discharge, the preionization is ignited between the plurality of pairs of the preliminary pin electrodes 13 and 14 of the first preionization means 11, and at the same time, the plurality of pairs of the preliminary pin electrodes 13 of the second preionization means 12 are ignited. , 14, the preionization is also ignited.

The preliminary ionization discharges of the plurality of pairs of preliminary pin electrodes 13 and 14 of the first and second preliminary ionization means 11 and 12 are carried out from the set on one end side provided with the trigger means 21 toward the other end side. It is fired sequentially, and the firing order is always almost the same timing. Moreover, the first preliminary ionization means 11 and the second
Spark discharge with the preionization means 12 is ignited with almost no time lag. That is, the firing is performed at the timing of several ns or less, which is almost the same as the shift of the trigger-discharge in the two sets of trigger-pin electrodes 22 and 23 of the trigger means 21.

The spark discharges of the first preionization means 11 and the second preionization means 12 are ignited at substantially the same timing, and the first discharge space portion 2A and the second discharge space portion 3A are formed. When pre-ionized, the main discharges are ignited in the discharge spaces 2A, 3A at substantially the same timing, so that the laser light L is generated in the discharge spaces 2A, 3A almost at the same time. That is, since the laser light L is generated in each of the discharge space portions 2A and 3A having an amplifying action by the main discharge, the laser light generated in each of the discharge space portions 2A and 3A is generated. The light L is amplified in the other discharge space.

The laser light L thus amplified is repeatedly reflected by the high reflection mirror 33a for the resonator and the output mirror 33b, and is oscillated from the output mirror 33b side.

That is, according to the gas laser device having the above-mentioned structure, the trigger means 2 initially arranged in the installation space S is provided.
The two sets of trigger-pin electrodes 22 and 23 of No. 1 ignite a trigger-discharge, whereby the first and second preionization means 11 and 12 provided with the installation space S interposed therebetween are spun.
Since the electric discharge is ignited, the main discharge is ignited in the first and second discharge space portions 2A and 3A almost at the same time.
The light L can be generated.

Therefore, the first discharge space portion 2A and the second discharge space portion 2A
In the discharge space 3A, it is possible to prevent jitter from occurring in the preionization and the main discharge as shown in FIGS. 4 (a) and 4 (b). Therefore, the laser light L should be generated at substantially the same timing. You can

FIG. 5 shows a second embodiment of the present invention. In this embodiment, a dielectric 41 such as quartz is provided between the upper trigger pin electrode 22 and the lower trigger pin electrode 23 of the trigger means 21.

According to this structure, the breakdown voltage of the discharge generated along the dielectric 41 is reduced to about 1/10 of the breakdown voltage of the gas gap. Even if the gap with the lower trigger-pin electrode 23 is not made smaller than the gap between the pin electrodes of the preionization means, spark discharge can be easily generated.

FIG. 6 shows a third embodiment of the present invention. In the third embodiment, the tips of the upper trigger pin electrode 22 and the lower trigger pin electrode 23 of the trigger means 21 are tapered so as to have edges 22a and 23a on their tip surfaces.

With such a shape, the inequality of the electric field between the electrodes is increased, and the electric field is concentrated on the edges 22a and 23a. Therefore, as in the second embodiment, the electrode 2 is formed.
Even if the gap between 2 and 23 is not reduced, spark discharge can be easily generated.

Although the gas laser device in which two main discharge parts are arranged in series has been described in the above embodiment, the number of main discharge parts may be three or more. Further, the trigger means arranged in the adjacent parts of the plurality of main discharge parts is not limited to two pairs of pin electrodes, and may be one pair or three or more pairs, in short, both sides of the trigger means. It suffices as long as the spark discharge can be generated under the same condition in each of the arranged preionization means.

[0038]

As described above, according to the present invention, the trigger means composed of the upper trigger-pin electrode and the lower trigger-pin electrode is provided in the adjacent portions of the plurality of main discharge portions, and the trigger means between the trigger-pin electrodes is provided. The spark discharge was made easier than the spark discharge between the pin electrodes for preionization.

Therefore, since the spark discharge of the trigger means is used as a seed, the spark discharge can be ignited under the same condition to the pair of preionization means arranged on both sides of the trigger means. Laser light can be generated at the same timing from the discharge space portion preionized by the preionization means.

If laser light can be generated from a plurality of discharge spaces at the same timing, the laser light is amplified in the other discharge spaces, so that the laser light output is increased. be able to.

Further, the spark discharge for pre-ionization and the main discharge in the discharge space hardly generate jitter, respectively, so that it is possible to ensure synchronization with other laser devices. There is also.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view of an end portion of a first main discharge means and a second main discharge means that are also adjacent to each other.

FIG. 4 is an operation waveform diagram of preionization and main discharge.

FIG. 5 is an enlarged view of a trigger electrode showing a second embodiment of the present invention.

FIG. 6 is an enlarged view of a trigger electrode showing a third embodiment of the present invention.

FIG. 7 is an operation waveform diagram of conventional preionization and main discharge.

[Explanation of symbols]

1 ... Laser tube, 2, 3 ... Main discharge part, 4 ... Cathode, 5 ... Anode, 8 ... High-voltage power supply, 11, 12 ... Pre-ionization means, 13 ...
Upper spare pin electrode, 14 ... Lower spare pin electrode, 21 ... Trigger means, 22 ... Upper trigger-pin electrode, 23 ... Lower trigger-pin electrode.

Claims (5)

[Claims] 1. A gas laser device for generating laser light by exciting a gas laser medium by electric discharge, wherein a laser tube accommodating the gas laser medium and a cathode and an anode are opposed to each other. A main discharge means having a plurality of main discharge parts arranged in series, a high voltage power supply for applying a high voltage to the cathode and anode of each of the main discharge parts to ignite the main discharge in the discharge space between these electrodes, An upper spare pin electrode and a lower spare pin electrode whose tips are opposed to each other through a predetermined gap form a pair,
Preliminary ionization means for preliminarily ionizing the discharge space portion prior to the main discharge in the main discharge portion by arranging a plurality of pin electrode pairs laterally of the electrodes of the main discharge portion, and the main discharge portion Of the upper trigger pin electrode and the lower trigger pin electrode which are arranged between the adjacent end portions of the above, and are set in a state where discharge is more likely to occur than the above-mentioned preionization means.
And a gas laser device. 2. The gap between the tips of the upper trigger electrode and the lower trigger electrode facing each other is set smaller than the gap between the tips of the upper preliminary pin electrode and the lower preliminary pin electrode of the preionization means. The gas laser device according to claim 1, wherein 3. The gas laser device according to claim 1, wherein a dielectric is provided in a gap between the tips of the upper trigger electrode and the lower trigger electrode facing each other. 4. The gas laser device according to claim 1, wherein the tip portions of the upper trigger electrode and the lower trigger electrode are formed in a tapered shape having an edge at the tip. 5. The gas reservoir according to claim 1, wherein two or more sets of an upper trigger electrode and a lower trigger electrode are arranged on both sides of adjacent ends of the main discharge portion. -The device.