JPH057042A - Gas laser apparatus - Google Patents

Abstract

PURPOSE:To obtain laser-beam of high oscillation efficiency by installing a first and a second discharge gaps which are connected in series with a preliminary ionization part and connected in parallel with main electrodes. CONSTITUTION:When a thyristor is turned on, electric charges applied to an inductor 14 and charges in a charge-discharge capacitor 12 are applied across a pair of a first and a second discharge gaps 15, 17. Thereby series breakdown is generated in the discharge gaps 15, 17, which are electrically connected. As the result, electric charges are transferred to a pair of peaking capacitors 16. At this time, ultraviolet radiation is generated by the discharge generated in the first and the second discharge gaps 15 and 17. A discharge space 4 between a pair of main electrodes 2a, 2b is irradiated with the ultraviolet radiation, and preliminary ionization occurrs. Thus a main discharge is ignited between a pair of the main electrodes. Said main discharge is generated in the manner in which electric charge stored in a pair of peaking capacitors 16 flow inversely in the second discharge gap 17 and electric charges are applied across a pair of the main electrodes. Main discharge is ignited and gas laser medium is excited. Thus laser beam is radiated.

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 that discharges a gas laser medium to generate laser light.

[0002]

_2. Description of the Related Art A gas laser device such as a CO ₂ laser or an excimer laser has an airtight container in which a gas laser medium is sealed. A main electrode is arranged in this airtight container. When electric energy is applied between the main electrodes to generate a glow discharge, the gas laser medium is excited and laser light is generated.

In order to stably generate the glow discharge between the pair of main electrodes, the discharge space between the pair of main electrodes is preionized. As a method of preionization,
A preionization circuit in which a peaking capacitor and a discharge gap connected in series are connected in parallel to a pair of main electrodes is provided, and the discharge space is preionized by ultraviolet rays generated by the discharge between the discharge gaps. ing.

According to such a preionization method, the strength of preionization in the discharge space is proportional to the number of discharge gaps. That is, if the number of discharge gaps is small,
The amount of generated ultraviolet rays becomes insufficient, and the discharge space cannot be sufficiently preionized.

In the conventional preionization circuit, in order to increase the number of discharge gaps, it is necessary to increase the number of peaking capacitors as the number of discharge gaps increases. However, since the peaking capacitor is relatively large, and the number of peaking capacitors that can be provided in parallel with the main electrode is limited in terms of space, it is not possible to sufficiently increase the number of discharge gaps. was there. Further, it has been considered to provide a large number of discharge gaps in parallel with one peaking capacitor or a plurality of discharge gaps in series.

[0006]

As described above, in the conventional gas laser device, the number of discharge gaps cannot be increased sufficiently, so that the preionization of the discharge space can be performed with sufficient strength. There was something I couldn't do.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a gas laser device capable of increasing the number of discharge gaps without being limited in space. Especially.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a pair of main electrodes that generate a main discharge and a peaking capacitor connected in parallel with the main electrodes so as to place them in the vicinity of the main electrodes. A pre-ionization unit having a first discharge gap provided in parallel with the main electrode and a second discharge gap connected in series to the first discharge gap, a charging / discharging capacitor, and charging the charging / discharging capacitor. A charge transfer circuit that transfers the electric charge of the peaking capacitor to the peaking capacitor via the switching element through the first and second discharge gaps, and the electric charge of the peaking capacitor via the first discharge gap. And a main discharge circuit for generating a main discharge between the main electrodes preionized.

[0009]

According to the above construction, when the switch element is closed and the charge accumulated in the charge / discharge capacitor is flown, discharge is generated in the first discharge gap and the second discharge gap provided in series. , Can generate ultraviolet rays.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, in which reference numeral 1 is an airtight container formed in a cylindrical shape. In the airtight container 1, a pair of main electrodes 2a and 2b facing each other are arranged along the axial direction of the airtight container 1. A gas laser medium is enclosed in the airtight container 1. The gas laser medium is circulated in the direction shown by the arrow by the blower 3 provided in the airtight container 1, and the pair of main electrodes 2
In the discharge space portion 4 between a and 2b, discharge is excited as described later. The gas laser medium whose temperature has risen due to discharge excitation is cooled by the heat exchanger 5 and recirculated.

A preionization section 6 is connected in the vicinity of the pair of main electrodes 2, and a charge transfer circuit 8 is constructed with the preionization section 6 as a part. The charge transfer circuit 8 includes a high-voltage power supply 9, a resistor 11 and a charging / discharging capacitor 12 that are sequentially connected to one end of the high-voltage power supply 9, and one end and the other end of the high-voltage power supply 9, that is, a high-voltage power supply. A circuit having a thyratron 13 as a switch element and an inductance 14 connected in parallel with 9 is connected. In addition, the preionization unit 6 is a first electrode including a pair of pin electrodes 15a.
Discharge gap 15 and one end of the peaking capacitor 1 connected in series with this discharge gap 15.
6 is connected to one of the main electrodes 2a via a pin electrode 15
It has a second discharge gap 17 composed of a pair of pin electrodes 17a whose other end on the a side is connected to another main electrode 2b.

Next, the operation of the gas laser device having the above structure will be described. First, when the high voltage power supply 9 is turned on, the charging / discharging capacitor 12 is charged with a high voltage through the resistor 11 and the inductance 14.

After charging, when the thyratron 13 is turned on, the charge charged in the charge / discharge capacitor 12 is applied to both ends of the inductance 14. Inductance 1
The charge applied to the charge-discharge capacitor 4 is a pulse charge having a high-frequency component and has a high impedance.
Is applied to the discharge gap 17 of. As a result, the discharge gaps 15 and 17 break down in series and become conductive, and the charge charged to the pair of peaking capacitors 16 is transferred to the charge / discharge capacitor 12. At this time, the first discharge gap 15 and the second discharge gap 17
Ultraviolet rays are generated by the discharge generated in and, and the ultraviolet rays irradiate the discharge space portion 4 between the pair of main electrodes 2a and 2b,
Preionize.

When the discharge space 4 is sufficiently preionized, the main discharge is ignited between the pair of main electrodes 2a, 2b.
In this main discharge, the electric charge charged in the pair of peaking capacitors 16 flows backward through the second discharge gap 17, and the pair of main electrodes 2a, 2a does not pass through the first gap 15 as in charging. It is performed by applying a charge between 2b. When the main discharge is ignited, the gas laser medium contained in the airtight container 1 is excited and laser light is emitted.

As described above, by providing the first discharge gap 15 and the second discharge gap 17 in series in the preionization circuit 6, it is possible to increase the amount of ultraviolet rays that preionize the discharge space 4. You can If the amount of generated ultraviolet rays increases, the preionization of the discharge space portion 4 can be performed with sufficient strength, and thus high laser oscillation efficiency can be obtained.

Further, in the above-mentioned one-time main discharge, the second discharge gap 17 is discharged twice, whereas the first discharge gap 15 is discharged once. Therefore, the first discharge gap 15 is discharged. The temperature rise of the pin electrode 15a that forms the electrode is suppressed to a low level, the decrease of the dielectric breakdown voltage due to the spark generation is small, and sufficient ultraviolet light is generated even in the high repetitive pulse operation, and the electrode itself is not consumed. I'm sorry.

The ultraviolet light generated in the first discharge gap 15 strongly irradiates the vicinity of the lower main electrode 2b, and the ultraviolet light generated in the second discharge gap 17 strongly irradiates the middle part of the discharge space 4. Therefore, it is possible to realize a discharge having a fast rise.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the first discharge gap 15 'provided in the preionization section 6 is connected to the lower main electrode 2b by one pin electrode 15a.
Are formed so as to face each other, while the second gap 1 is formed.
7 in series with two peaking capacitors 16a, 16b
Is provided, the discharge gap for pre-ionization can be increased even in such a configuration.

In the above embodiment, the high voltage pulse generated at both ends of the inductance 14 when the thyratron 13 is turned on is used to generate the pulse high voltage.
The pulse high voltage may be generated by other known means.

[0021]

As described above, according to the present invention, the preionization section for preionizing the discharge space between the pair of main electrodes is connected in series and in parallel to the main electrode. The first discharge gap and the second discharge gap are provided.

Therefore, the number of discharge gaps for pre-ionizing the discharge space can be increased without being limited by the number of peaking capacitors that can be arranged on the side of the main electrode, and the center of the electrode in the discharge space can be increased. Pre-ionization of the part and the vicinity of the electrode can be performed quickly with strong ultraviolet light, so that the pre-ionization of the discharge space can be performed quickly and reliably, which can uniformly generate the main discharge and obtain a laser beam with high oscillation efficiency. I can do it.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a gas laser device showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a preionization circuit showing another embodiment of the present invention.

[Explanation of symbols]

2a, 2b ... Main electrodes, 8 ... Charge transfer circuit, 12 ... Charge / discharge capacitor, 13 ... Thyratron (switching element), 15 ... First discharge gap, 16 ... Peaking capacitor, 17 ... Second discharge gap.

Claims (1)

Claim: What is claimed is: 1. A pair of main electrodes for generating a main discharge, and a peaking capacitor connected in parallel with the main electrodes and provided in the vicinity of the main electrodes in parallel with the main electrodes. A pre-ionization unit having a first discharge gap and a second discharge gap connected in series to the first discharge gap, a charge / discharge capacitor and an electric charge charged in the charge / discharge capacitor, 2 through the discharge gap of 2
A charge transfer circuit that transfers to a king capacitor via a switching element, and a main discharge circuit that generates a main discharge between the main electrodes that are pre-ionized by the charges of the peaking capacitor via the first discharge gap. A gas laser device comprising: