JPH0422179A - Laser oscillator - Google Patents

Abstract

PURPOSE:To reduce an influence by an electric field formed in the tip part on an electric discharge operation, to enhance the stability of the electric discharge operation and to prevent a change in a laser output by a method wherein a firing auxiliary tube is installed and the cross-sectional face in its tip part is worked to be a round and protrusionless shape. CONSTITUTION:A firing auxiliary tube 10a is attached to a tube body of a discharge-tube group 1 situated between an anode 2a and a cathode 3a; and it is connected electrically to the anode 2a. Since the cross-sectional shape in the tip part of the tube 10a is formed to be a round and protrusionless shape, an electric field generated near the tip part does not generate an equipotential line which is swollen toward the inside of a discharge tube. Consequently, it is not required to form an electromagnetic lens inside the discharge tube, and also a streamer is not formed near the tip part of the auxiliary tube 10a when a pulse is oscillated (in a state that the pulse in a pulse-train shape is output on a fixed cycle). Consequently, an electric discharge at a laser oscillator is stabilized, and a stable laser output without change can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a laser oscillator that generates laser light for cutting, welding, heat treatment, and the like.

2. Description of the Related Art The structure of a conventional laser oscillator of this type will be described with reference to FIG. A discharge tube group 1 consisting of one or more discharge tubes includes an anode 2a for each discharge tube.

A set of discharge electrodes consisting of a cathode 2b, a cathode 3a, and a cathode 3a and sb are provided, and in the example shown in FIG. 3, two sets of discharge tubes are formed.
The two sets of discharge tubes are arranged symmetrically to form a discharge tube group 1, and power is supplied to each discharge tube from a high voltage power source 4. Further, output mirrors 5. are provided at both ends of the discharge tube group 1. A termination mirror 6 is arranged to form an optical resonator. Further, a circulating tube body 7 having an approximately E-shape is formed between the cathode types 1i3a, 3b at both ends of the discharge tube group 1 and the anode electrodes 1i2a, 2b at the center.
are connected to form a gas circulation path, and this circulation tube body 7 is provided with a blower 8 for circulating gas and a plurality of heat exchangers 9 for cooling the gas. There is still a discharge starting auxiliary tube 10a on the outer periphery of the discharge tube.

10b, and is electrically connected to the positive electrodes 2a, 2b or the negative electrodes 3a, 3b.

Next, FIG. 4A shows an enlarged view of the discharge tube section on the right side.

As is clear from FIG. 4A, each discharge tube is equipped with a set of discharge electrodes consisting of an anode 2a and a cathode 1i3a, which are connected by a discharge tube body to form a discharge section. The discharge starting auxiliary tube 10a electrically connected to the anode 2a or the cathode 3a is still arranged, and the discharge starting auxiliary tube 10a is still arranged.
The tip of 0a was used with the sharp edges and protrusions created when cutting the material left intact.

In a laser oscillator configured in this way, the gas flow direction, the discharge direction, and the laser beam oscillation axis are coaxial, so when viewed from the optical axis direction, the discharge and the gain distribution formed by the discharge are concentric. It has good symmetry. Therefore, it is said that the machining performance is good when machining is performed using the output laser light.

Problems to be Solved by the Invention However, the discharge starting auxiliary tubes 10a, 10b
Due to the influence of the electromagnetic lens-shaped electric field generated from the tip of the discharge tube, a large gap may appear in the center of the discharge tube near the tip of the discharge starting auxiliary tube, especially during pulse oscillation (a state in which the pulse train is output intermittently at regular intervals). There was a problem that an IJ-ma was formed, the discharge became unstable, and the laser output fluctuation increased.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a discharge starting auxiliary tube which is attached to the outer periphery of the discharge tube between the anode and the cathode and is electrically connected to the anode or the cathode. The vertical section is processed into a round shape without protrusions.

Effect: According to the present invention, the electric field generated by the tip of the discharge starting auxiliary tube is prevented from wrapping around the inside of the discharge tube to form an electromagnetic lens shape, reducing the influence of the electric field on the discharge, and improving the stability of the discharge. It is possible to improve this and eliminate fluctuations in laser output.

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

FIG. 1 shows an embodiment of the present invention. Although FIG. 1 shows the discharge tube section located on the right side of the discharge tube group 1, the discharge tube section on the left side is in a symmetrical relationship with this, and the effects of the present invention are the same. In FIG. 1A, 10a is a discharge starting auxiliary tube, which is electrically connected to the anode 2a. 3a is a cathode,
1 is a tube body of a group of discharge tubes. FIG. 1B is an enlarged vertical cross-sectional view of the main part in FIG. 1A, showing the vicinity of the tip of the discharge starting auxiliary tube 10a in the present invention, and the vertical cross-section of the tip has a round shape without protrusions. . Reference numeral 11 denotes a nupacer for keeping the discharge starting auxiliary tube at a constant distance from the tube bodies of the discharge tube group.

Figure 4 shows the discharge tube section in a conventional example, and the cross-section of the tip of the discharge starting auxiliary tube shows that, as shown in Figure 4B, the tip of the tube has sharp burrs that are produced during the cutting process toward the inside of the tube. remains. These sharp points pointing inward create an electric field that bulges inward of the discharge tube during discharge, as shown in FIG. 6. In the figure, the broken lines indicate the equipotential lines of the electric field, and the equipotential part bulging inside the discharge tube forms a circle concentrically with the discharge tube, forming an electromagnetic lens inside the discharge tube. A large metrimer was formed in the center, making the discharge unstable and causing fluctuations in laser output.

On the other hand, the electric field generated near the tip of the discharge starting auxiliary tube having the tip shape shown in FIG. 1B is as shown in FIG. 2, and there is no equipotential line that swells toward the inside of the discharge tube. Therefore, according to the present invention, there is no need to form an electromagnetic lens within the discharge tube, no streamer is formed, and therefore the discharge is stabilized and fluctuations in laser output are eliminated.

Effects of the Invention As is clear from the above description, according to the present invention, the discharge in the laser oscillator can be stabilized, and stable laser output without fluctuation can be obtained.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1A is a vertical cross-sectional view showing the configuration of a discharge tube section in an embodiment of the present invention, FIG. 1B is an enlarged vertical cross-sectional view of the main part of FIG. 3 is a diagram showing the state of the electric field generated near the tip of the discharge starting auxiliary tube according to the present invention, FIG. 3 is a diagram showing the configuration of the entire laser oscillator, and FIG. 4A is a longitudinal section showing the configuration of the discharge tube section in the conventional example. 4B is an enlarged vertical sectional view of the main part of the same figure, and FIG. 5 is a diagram showing the state of the electric field generated near the tip of the discharge starting auxiliary tube in the conventional example. 1...discharge tube group, 2a, 2b...positive box,
3a. 3b...Cathode, 4...High voltage power supply, 6...
...Output mirror 6...Terminal mirror 7...
...Circulation pipe body, 8...Blower, 9...Heat exchanger, 10 a, 10 b...Discharge starting auxiliary pipe, 11
...Nupesa. Name of agent Patent attorney Shigetaka Awano and 1 other person (Oa7 Figure 09 Horn Oa Figure Figure 2-2b 3a, 3b toa, rob Discharge tube group positive material Fl && Voltage Power source υ; Ra - N side mirror l11IIW 琶 杢Ll, darkness 艷?Tam exchange discharge time 1W

Claims (1)

[Claims] A discharge tube group consisting of one or more discharge tubes and having at least one pair of discharge electrodes consisting of an anode and a cathode, a mirror for laser resonance disposed at both ends of this discharge group, and a It consists of a circulation pipe connected to the discharge group and forming a gas circulation path together with the discharge group, and a blower that circulates gas as a laser medium in the gas circulation path,
A laser oscillator characterized in that a longitudinal section of a distal end of a discharge starting auxiliary tube attached to the outer periphery of the discharge tube between the anode and the cathode and electrically connected to the anode or the cathode is processed into a round shape without protrusions. .