JPH0240974A - Gas laser oscillator - Google Patents

Abstract

PURPOSE:To realize high efficiency of laser oscillation by installing a protruding stripes along the tube axis on the inner wall, of a discharge tube, corresponding with the end-egdes of metal electodes. CONSTITUTION:The inner diameter of a cylindrical discharge tube 1 is 200mm, and the radial thickness is about 3mm. Along the tube axis, four semi-columnar protruding stripes are formed on the inner wall part, of discharge tube, corresponding with the end-edges 2a, 3a of a pair of metal electrodes 2, 3 in the axial direction of external peripheral surface of the tube 1. The radial thickness of these parts only become thick, and the concentration of electric field can be avoided. Further, the tube wall of other parts do not obstruct power injection, so that laser beam can be led out with high efficiency.

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 are aligned, and particularly relates to a gas laser oscillation device that achieves high laser oscillation efficiency. It is related to the 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 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 metal 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 partially reflective mirror (7
) constitutes an optical resonator, and the discharge tube (
An air pipe (8) is provided in communication from the center between the electrodes (2) and (3) of the discharge tube (1), and a pair of - and air pipes are provided between both ends of the discharge tube (1) and the other end of the air pipe (8). The branch pipes (9) and (10) are arranged in communication with both pipes (+) and (8) to form a pair of circulation passages branching in two directions from the center of the discharge tube (1). A blower (11) is provided in the middle of the air pipe (8), and the air discharge in the discharge space (5) and the blower (11) are provided in the air pipe (8) on both sides of the air pipe (11). A so-called axial flow type laser oscillation device is known, which is provided with a heat exchanger (12) (+3) for cooling the laser gas heated to h' 7M by driving.

In addition, as a 1 Fi blower (II), a discharge space (5
), it is necessary to use one that has an air blowing capacity that can obtain a gas flow with a flow velocity of about 100 m/see.

In the conventional device having the configuration L, first, a pair of metal electrodes (2H
When a high-frequency high voltage is applied from the high-frequency power source (4) to 3) to generate a glow-like discharge in the discharge space (5), the laser gas passing through the discharge space (5) obtains the emitted-h energy. Excited, total reflection mirror (6) and)
Due to the action of the optical resonator formed by the mirror (7) with a thickness of 1.5 mm, a resonant state is created, and as a result, a laser beam (B) is output from the partially reflecting mirror (7), and this laser beam (
B) will be used for laser processing 1.1.

By the way, when applying a high frequency high voltage between the metal electrodes (2) (31 to emit the laser beam (B) as shown in [-], the edges (2a) (3a) of the picture electrodes (2) (3) The electric field concentrates in the discharge space (5), deteriorating the discharge condition.In particular, changes in the dielectric loss of the discharge tube (1), which is a dielectric material, cause the discharge space (5) to deteriorate.
The power that can be injected within +1J will be determined.

For this reason, if the wall thickness of the discharge tube (1) is thin, the discharge space (5)
Non-uniformity occurs in the electric field distribution, causing discharge concentration, and conversely,
If the wall thickness of the discharge tube (1) is thick, the power that can be injected into the discharge space (5) will decrease due to the dielectric loss of the discharge tube (1), but conventionally, emphasis has been placed on preventing discharge concentration. ,
A thick discharge tube (+) was used.

[Problem to be solved by the invention]

However, in the case of a conventional gas laser oscillator using a discharge tube (1) with a large wall thickness, the loss of power due to the dielectric loss of the discharge tube (+) inevitably increases. There was a problem in that the laser beam could not be extracted efficiently.

The present invention has been made in order to solve these conventional problems, and is a gas laser oscillation device that can eliminate discharge concentration in the discharge space within the discharge tube and can also minimize the loss of power injected into the discharge tube. The first objective is to provide the following.

[Means to solve the problem]

Written in[. In order to achieve the first objective, the present invention allows a laser gas to flow in the optical axis direction inside a discharge tube made of a dielectric material, and creates a gap between metal electrodes provided on the outer circumferential surface of the discharge tube and facing each other in the tube diameter direction. In a gas laser oscillation device that applies a high frequency voltage to generate a discharge in the discharge tube and uses the discharge as a laser excitation source to generate a laser beam in the tube axis direction of the discharge tube, the discharge corresponding to the edge of the metal electrode It is characterized in that a protrusion is formed on the inner wall portion of the tube along the tube axis direction.

[For production]

In the present invention, according to the configuration described in 1-, only the wall thickness of the inner wall portion of the discharge tube corresponding to the edge of the metal electrode is reduced by 1"(1") by the convex strip.
This avoids electric field concentration, and the thickness of the tube wall in other parts of the discharge tube can be made to the extent that it does not interfere with power injection, making it possible to take out the laser beam with high efficiency. become.

〔Example〕

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

Note that this embodiment device has the same basic configuration as the conventional example described above, so the configuration 71F2 and the function (common parts will be given common symbols, and their explanation will be omitted to avoid duplication. It shall be.

In FIG. 1, in the gas laser oscillation device according to this embodiment, the inner diameter of the cylindrical discharge tube (1) is 2011I.
The wall thickness is 31 for I+, and this discharge tube (1)
A pair of metal electrodes (2) formed in the tube axis direction on the outer peripheral surface of the
Discharge tubes (+) corresponding to edges (2a) and (3a) in (3)
) are formed with convex stripes (14) in the shape of 11 columns with 4 squares extending along the tube axis direction.

Figure 2 shows the results of measuring the relationship between the laser output efficiency and the presence or absence of the protruding stripes (14) provided on the inner wall of the discharge tube (1). ) has a convex strip (14) on the inner wall, and the output efficiency of the furnace is much higher than that of the inner wall having a uniform thickness around the entire circumference.

〔Effect of the invention〕

As explained below, according to the present invention, a convex strip along the tube axis direction is formed on the inner wall portion of the discharge tube corresponding to the edge of the metal electrode provided on the outer peripheral surface of the discharge tube, so that the inside of the discharge tube is Since the electric field distribution is made uniform, electric field concentration at the edge forming part of the metal electrode is avoided, and the wall thickness of other parts of the discharge tube can be made thick enough not to interfere with power injection. Therefore, the laser beam t can be extracted with high efficiency. Therefore, it has achieved excellent effects such as being able to reduce power consumption, being highly economical, and realizing crystalline laser processing performance.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention; Fig. 1 is a perspective view of a mold part of a discharge tube; Fig. 2 is a bar diagram showing the relationship between the laser mountain internal efficiency and the presence or absence of protrusions provided on the inner wall of the discharge tube; Fig. 3 is a longitudinal sectional view of a conventional example, and Fig. 4 is a longitudinal sectional side view of a conventional discharge tube. (1)...discharge tube, (2)(3)...metal electrode, (
2a) (3a)...Edge of metal electrode, (14)...Convex strip. Figure 1 Figure 3 Figure 4 The nature of the convex stripes on the inner wall of the discharge tube

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 generates a laser beam in the tube axis direction of the discharge tube using this discharge as a laser excitation source, a convex strip along the tube axis direction is provided on the inner wall portion of the discharge tube corresponding to the edge of the metal electrode. A gas laser oscillation device characterized in that: