JPH0239870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an axial flow type silent discharge excited gas laser device, which is capable of outputting high quality laser light.

[Prior art]

2. Description of the Related Art Conventionally, devices of this type are shown in FIGS. 1 and 2. In the figure, reference numeral 1 denotes a discharge tube, which is made of a dielectric material and has a substantially cylindrical shape, and a laser medium gas 2 is supplied to the discharge tube by appropriate means. Reference numerals 3A and 3B are electrodes, and these electrodes are disposed facing each other in close contact with the outside of the discharge tube 1, and an AC power source 4 is connected between the electrodes.

When an AC voltage is applied between the electrodes 3A and 3B by this AC power supply 4, a silent discharge 5 is generated within the discharge tube 1, and a total reflection mirror 6 and a partial transmission mirror provided at the end of the discharge tube are 7, laser oscillation is generated. Laser light 8 resulting from the laser oscillation is output from the partially transmitting mirror 7 side and used for laser processing or the like.

By the way, the distance between the electrodes 3A and 3B is long at the center but short at the ends, and therefore the silent discharge 5 is strongly generated at the ends of the electrodes 3A and 3B. In the figure, the strong parts of the silent discharge 5 are marked darkly.

Since the conventional axial flow type silent discharge excited gas laser device is configured as described above, the silent discharge 5
is not uniform, and the electric field is concentrated at the ends 9 of the electrodes 3A and 3B, which may cause dielectric breakdown of the discharge tube 1.Also, since the laser oscillation is not uniform, the quality of the laser oscillation cannot be improved. The drawback was that it was difficult to obtain a single mode.

[Summary of the Invention] The present invention eliminates the above-mentioned conventional drawbacks, and includes a substantially cylindrical discharge tube made of a dielectric, a means for flowing a laser medium gas inside the discharge tube, and a discharge tube. Equipped with an electrode arranged on the outside,
In an axial silent discharge excited gas laser device that excites the laser medium gas and generates laser light by applying an alternating current voltage to the electrode and generating a silent discharge in the discharge tube, the discharge made of the dielectric material is used. The discharge tube is configured such that the thickness of the tube is thin at the center of the electrode and becomes thicker as the distance from the center increases, and a pair of electrodes made of a flat dielectric material are provided on the outside of the discharge tube. This is an axial flow type silent discharge that can make the discharge space uniform by applying an alternating current voltage to the electrodes, and can therefore output high-quality laser light. The present invention provides an excited gas laser device.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows a cross section of the discharge tube, and corresponds to FIG. 2 described in the above conventional example. In FIG. 3, the same reference numerals as in FIG. 1 or 2 indicate the same or corresponding parts, but as mentioned above, the thickness of the approximately cylindrical discharge tube 1 made of dielectric material is , the above electrodes 3A, 3
The discharge tube is constructed so that it is thin at the center of B and becomes thicker as it gets farther from the center. Part 10 of the discharge tube 1 configured in this way
The capacitance due to the dielectric material constituting the discharge tube is larger than that of the portion 11, and therefore the impedance to alternating current is high. When applied, the portion 10 in the electrodes 3A, 3B
Although the discharge distance at the region 11 is longer than the discharge distance at the portion 11, and therefore the discharge voltage becomes higher, the current of the silent discharge 5 becomes uniform, and a uniform discharge space can be obtained. Further, the electrodes 3A and 3B are formed of a flat conductor, and as shown in FIG. 3, the part that is in close contact with the discharge tube 1 has a concave shape as shown in the conventional example of FIG. They are connected by planes, not faces.

In the above embodiment, the thickness of the approximately cylindrical discharge tube 1 made of a dielectric material is thin at the center of the electrodes 3A, 3B, and becomes thicker as the distance from the center increases. Although the shape was constructed,
As shown in FIG. 4, electrodes 3A and 3B are attached to the discharge tube 1.
By attaching a dielectric 12 having a shape that is thin at the center part and thickens as it gets farther from the center, the thickness of the discharge tube 1 is substantially thinner at the center part of the electrodes 3A, 3B, and the thickness becomes thinner at the center part. A similar effect can be obtained by increasing the thickness as the distance increases. In FIG. 4, the same reference numerals as in FIG. 3 indicate the same or corresponding parts.

〔Effect of the invention〕

As described above, the present invention includes a substantially cylindrical discharge tube 1 made of a dielectric material, a means for flowing a laser medium gas 2 inside the discharge tube, and a pair of flat plates disposed outside the discharge tube. By applying an AC voltage from an AC power supply 4 to the electrodes and generating a silent discharge 5 in the discharge tube, the laser medium gas 2 is excited and a laser beam 8 is generated. In the axial flow type silent discharge excited gas laser device, the thickness of the discharge tube 1 made of the dielectric material is thin at the central portion of the electrodes 3A and 3B,
In addition, since the discharge tube is configured so that it becomes thicker as it gets farther from the center, it is easier to form and assemble the electrodes, and the discharge space becomes uniform, making it possible to output high-quality laser light. can.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view showing a conventional axial flow type silent discharge excited gas laser device, Fig. 2 is an enlarged longitudinal sectional side view of the one shown in Fig. 1, and Fig. 3 is an axial flow type showing an embodiment of the present invention. FIG. 4 is a longitudinal side view of the silent discharge excited gas laser device, and FIG. 4 is a longitudinal side view showing another embodiment. 1: Discharge tube, 2: Laser medium gas, 3A, 3
B: Electrode, 4: AC power supply, 5: Silent discharge, 8: Laser light, 12: Dielectric material. Note that the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A substantially cylindrical discharge tube made of a dielectric, means for flowing a laser medium gas inside the discharge tube, and an electrode disposed outside the discharge tube, In an axial silent discharge excited gas laser device which excites the laser medium gas and generates laser light by applying an alternating current voltage to the electrode and generating a silent discharge in the discharge tube, the discharge made of the dielectric material The thickness of the tube is thin at the center of the electrode and becomes thicker as the distance from the center increases, and a pair of electrodes made of a flat conductor are closely attached to the outside of the discharge tube. An axial flow type silent discharge excited gas laser device characterized by the following: