JPH0240978A - Gas laser oscillator - Google Patents

Abstract

PURPOSE:To stabilize the state of discharge in a discharge space by installing a spare discharge electrode onto an outer circumferential surface on the upstream side of a laser gas upper than the metallic-electrode disposing section of a discharge tube. CONSTITUTION:A pair of spare discharge electrodes 14 are disposed oppositely onto an outer circumferential surface on the upstream side of a laser gas upper than the disposing sections of the metallic electrodes 2, 3 of a discharge tube 1. Fixed high-frequency voltage is applied to the electrodes 14, the laser gas flowing in an electric field is pre-ionized and forwarded to a downstream, and main discharge is conducted between the metallic electrodes 2, 3 shaped at regular intervals from the spare electrodes 14. According to the constitution, the output of laser beams is stabilized remarkably.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas laser oscillation device in which the axial direction of a discharge tube and the optical axis direction coincide with each other, and in particular, a gas laser oscillation device that takes measures to stabilize the discharge state in the discharge space. This invention relates to a gas laser oscillation device.

[Conventional technology]

Conventionally, as this type of gas laser oscillation device, for example, the third
As shown in FIG. 4 and FIG. 4, a pair of metal electrodes (2) (3 ) are arranged in close contact with each other in a state facing each other, and the pair of metal electrodes (2) and (3) are connected to a high frequency AC power source (4),
For example, 13.56MHz, 2k for both electrodes (2) and (3).
While applying a high frequency high voltage of V, both electrodes (2) (3)
A total reflection mirror (6) and a partial reflection mirror (7) are arranged at fixed positions at both ends of the discharge space (5) in the discharge tube (1) sandwiched between them, and these total reflection mirrors (6) and a partially reflecting mirror (7) constitute an optical resonator, and an air pipe (8) is provided in communication with the center between the electrodes (2) and (3) of the discharge tube (1), and Both ends of the pipe (1) and the air pipe (8
) A pair of branch pipes (9) On) are connected between the other ends of both pipes (1) (
8) in communication with the discharge tube 2 from the center of the discharge tube (1).
A pair of circulation passages branching in the direction are formed, and furthermore, a blower (11) is provided in the middle of the air pipe (8), and a discharge is generated in the air pipe (8) on both sides of the blower (10). A so-called axial flow type gas laser oscillation device is known, which is provided with heat exchangers 02 and 13 for cooling laser gas heated by discharge in a space (5) and driving of a blower (11).

Note that the blower (11) needs to have a blowing capacity capable of producing a gas flow at a flow rate of about 100 m/sec in the discharge space (5).

In the conventional device with the above configuration, first, a pair of metal electrodes (2)
When a high-frequency high voltage is applied to (3) from the high-frequency power source (4) to generate a glow-like discharge in the discharge space (5), the laser gas passing through the discharge space (5) obtains the discharge energy and is excited. At the same time, the optical resonator formed by the total reflection mirror (6) and the partial reflection mirror (7) enters a resonant state, and the partial reflection mirror (7) outputs a laser beam (B). Laser beam (B)
will be used for purposes such as laser processing.

[Problem to be solved by the invention]

As mentioned above, when applying a high frequency high voltage between metal electrodes (2) and (3) to generate a laser beam (B), the discharge state is controlled by the impedance between the metal electrodes (2) and (3). However, in particular, the discharge space (5
), the laser gas flows at high speed, so the impedance fluctuates rapidly over time. Therefore, the discharge space (
5) In the case of conventional devices that do not take particular measures to stabilize the discharge within the discharge space (5), the discharge state within the discharge space (5) is unstable, making it impossible to obtain a laser beam (B) with a stable output. There was a point.

The present invention has been made in order to solve the above-mentioned conventional problems, and provides a gas laser that can suppress output fluctuations and obtain a laser beam with stable output by stabilizing the discharge state in the discharge space. The purpose is to provide an oscillation device.

[Means to solve the problem]

In order to achieve the above object, the present invention causes a laser gas to flow in the optical axis direction inside a discharge tube made of a dielectric material, and generates a high-frequency voltage between metal electrodes provided on the outer peripheral surface of the discharge tube so as to face each other in the tube diameter direction. In a gas laser oscillation device that generates a discharge in the discharge tube by applying A gas laser oscillation device characterized in that preliminary discharge electrodes are provided facing each other on the outer circumferential surface portion on the upstream side of the laser gas.

[For production]

With the above configuration, the present invention applies a predetermined high-frequency voltage to the pre-discharge electrode tube provided in the upstream portion of the laser gas in the discharge tube, pre-ionizes the laser gas flowing in the electric field, and then discharges the laser gas turned into plasma. The output of the laser beam can be stabilized by feeding it into the downstream side of the tube and causing a main discharge between the metal electrodes.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

This embodiment device has the same basic configuration as the conventional example described above, so parts with the same configuration and function will be given the same reference numerals, and their explanation will be omitted to avoid duplication. do.

In FIG. 1, in the gas laser oscillator according to this embodiment, a pair of preliminary discharge electrodes 04 are provided on the outer circumferential surface portion of the discharge tube (1), which is located upstream of the laser gas from the metal electrodes (2) and (3). A predetermined high-frequency voltage is applied between both pre-discharge electrodes 04) to pre-ionize the laser gas flowing in the electric field, and then the plasma-formed laser gas is transferred to the downstream side of the discharge tube. The main discharge is carried out between the metal electrodes (2) and (3) formed at a predetermined interval from the preliminary discharge electrode side.

FIG. 2 shows the results of measuring the stability of laser output in the device of the present invention equipped with a preliminary discharge electrode 04) and the conventional device without the same preliminary discharge electrode. As is clear from the results, By performing preliminary ionization of the laser gas on the preliminary discharge electrode side, the laser beam output is significantly stabilized.

〔Effect of the invention〕

As explained above, according to the present invention, since the preliminary discharge electrode is provided facing the outer peripheral surface portion of the discharge tube which is upstream of the laser gas than the metal electrode disposed portion, the discharge condition in the discharge space is As a result, a stable laser beam with suppressed output fluctuations can be extracted, making it possible to achieve high-quality laser processing.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a discharge tube showing an embodiment of the present invention, Fig. 2 is a graph showing the stability of laser output over time depending on the presence or absence of a preliminary discharge electrode, and Fig. 3 is a longitudinal cross-sectional view of a conventional example. Front view, 4th
The figure is a longitudinal sectional side view of a conventional discharge tube. (1)...discharge tube, (2)(3)...metal electrode. 0
4)...Preliminary discharge electrode. 1st 2nd

Claims (1)

[Claims] A laser gas is caused to flow in the optical axis direction within a discharge tube made of a dielectric material, and a high-frequency voltage is applied between metal electrodes provided on the outer peripheral surface of the discharge tube facing each other in the tube diameter direction to generate a discharge within the discharge tube. In a gas laser oscillation device that uses this discharge as a laser excitation source to generate a laser beam in the tube axis direction of the discharge tube, a preliminary discharge is applied to a portion of the outer circumferential surface of the discharge tube that is upstream of the laser gas from the metal electrode disposed portion. A gas laser oscillation device characterized by having electrodes facing each other.