JPS647512B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement of a discharge tube of an axial flow type silent discharge excited gas laser device.

[Prior art]

Conventionally, this type of technology is shown in Figures 1 and 2.
I got what is shown in the figure. Figure 1 is a cross-sectional view, Figure 2
The figure shows a longitudinal sectional view of FIG. In the figure, 1 is a discharge tube made of a dielectric material, and 2 is a laser medium gas, which flows in from the right side of the discharge tube 1 and flows out to the left side as seen in the figure. 3A and 3B are electrodes provided on the outside of the discharge tube 1, and 4 is an AC power source connected to the electrodes 3A and 3B. 5 is a silent discharge generated by applying voltage to the electrodes 3A and 3B from the AC power source 4;
Reference numeral 6 indicates a total reflection mirror, and reference numeral 7 indicates a partial transmission mirror. Laser oscillation is performed between the total reflection mirror 6 and this partial transmission mirror 7 by the action of the laser medium gas 2 and the silent discharge 5, and a laser beam 8 is generated. is outputted from the partially transmitting mirror 7 side.

Next, the operation will be explained. Figures 1 and 2
In the figure, electrodes 3A and 3B are connected by AC power source 4.
When a voltage is applied to the electrodes 3A and 3 in the discharge tube,
A silent discharge 5 is generated between B, and this silent discharge 5, the laser medium gas 2, the total reflection mirror 6 and the partial transmission mirror 7
Laser light 8 is generated by the action of. In this case, as shown in FIG. 2, where the intensity of the silent discharge 5 is shown in gradations, the intensity of the silent discharge 5 is greater at the end 9 where the distance between the electrodes 3A and 3B is short, and the closer it gets to the center, the more the intensity of the silent discharge 5 increases. Since the distance between the electrodes 3A and 3B becomes long, the intensity of the silent discharge 5 is small and the discharge current does not flow uniformly.

Conventional axial-flow type silent discharge excited gas laser devices are configured as described above, and since the intensity of the silent discharge is not uniform, the electric field is concentrated at the end of the electrode of the discharge tube, which may cause dielectric breakdown of the discharge tube. , the quality of the laser light is poor because the laser oscillation does not occur uniformly,
In addition, since there is a non-discharge area shown by 10 in FIG. 2, the intensity of laser oscillation is weakened, and it is difficult to obtain a single mode, which is considered to be a high-quality mode of laser oscillation.

[Summary of the invention]

This invention was made to eliminate the drawbacks of the conventional ones as described above, and the cross section of the discharge tube as viewed in the gas flow direction is divided into six or more parts, and a high-permittivity dielectric material and a low-permittivity dielectric material are used. are arranged next to each other alternately, electrodes are provided on the outside of the high-permittivity dielectric material, and an alternating current voltage is applied between these electrodes to obtain a uniform discharge space, thereby producing high-quality laser light. The present invention provides an axial flow type silent discharge excited gas laser device that can obtain the following.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows an example in which the cross section of the discharge tube 1 viewed in the gas flow direction is divided into six parts. In the figure, 11A, 11
B and 11C are high permittivity dielectrics, and electrodes 12A, 12B and 12C are provided on the outer walls, respectively. 13A, 13B, and 13C are low-permittivity dielectrics that are alternately adjacent to high-permittivity dielectrics 11A, 11B, and 11C, and the boundary 17 is bonded with low-melting-point glass or the like to maintain airtightness that can withstand vacuum. ing. In addition, high permittivity dielectrics 11A, 11B, 1
Titanium oxide, barium titanate, or a mixture of these and glass is used as the material for 1C, and glass is generally used as the material for the low dielectric constant dielectrics 13A, 13B, and 13C, but ceramics and the like are also used. Ru. 14 is a three-phase AC power supply, which has electrodes 12A, 12B, electrodes 12B, 12C as shown in the figure.
And voltages of each phase are applied between the electrodes 12A and 12C.

Next, the operation will be explained. In Figure 3,
When a voltage is applied from each phase of the three-phase AC power supply 14, a silent discharge 5 is generated between the electrodes 12A, 12B, 12B, 12C, and between the electrodes 12A, 12C, and the silent discharge 5 and the voltage described in FIG. Laser light 8 is emitted by the action of laser medium gas 2, total reflection mirror 6, and partial transmission mirror 7. in this case,
Since alternating current voltages with a phase difference of 120° are applied alternately to opposing electrodes, the number of discharges per unit time is tripled compared to conventional devices, and the discharge tube 1 is free from the noise described in FIG. 2. Since the discharge portion 10 is almost eliminated, the distribution of the silent discharge 5 is made uniform. As a result, a high-quality laser beam 8 with high oscillation intensity can be obtained.

In addition, although the above embodiment shows the case where the discharge tube is divided into 6 parts, the discharge tube is divided into 8 parts as shown in FIG.
The electrodes 12 are provided on the outer wall of the electrode 12, and the electrodes 12 are arranged adjacent to the four low permittivity dielectrics 13 alternately, and the two electrodes have a phase difference of 90°.
Even when voltage is applied to two sets of electrodes facing each other by the phase AC power supplies 15 and 16, or even when a multiphase AC voltage of three or more phases is applied by increasing the number of electrodes, the same effect as in the above embodiment is applied. It has the effect of

5 and 6, the high-permittivity dielectric 11, the low-permittivity dielectric 13, and the electrode 12 are made of planar members, and the discharge tube glued together at the boundary 17 is divided into eight parts as in the previous embodiment. An example of dividing into 6 parts is shown. According to this structure, since a planar member is used, it is easier to obtain than an arc-shaped member and is therefore low-cost. Also, when the boundary 17 is raised as shown in the figure, the distance between adjacent electrodes 12 is reduced. That is, it is possible to prevent dielectric breakdown on the surface of the low dielectric constant dielectric 13.

FIG. 7 shows a dielectric plate 18 of the discharge tube 1 by sandwiching a plate 18 of a dielectric material with good heat conductivity such as beryllia between the boundaries and protruding to the inside or outside of the discharge tube.
An example will be shown in which the heat of 1, 13 and the laser medium gas 2 can be effectively released to the outside.

〔Effect of the invention〕

As described above, according to the present invention, a discharge tube is formed by forming a plurality of sets of dielectric materials with a high dielectric constant and a dielectric material with a low dielectric constant adjacent to each other, and by applying an alternating current voltage to the electrodes to cause discharge, a homogeneous discharge tube can be formed. This has the effect of producing powerful laser light.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a conventional axial-flow type silent discharge excited gas laser device, FIG. 2 is a vertical cross-sectional view of FIG. 1, FIG. 3 is a vertical cross-sectional view showing an embodiment of the present invention, and FIG. 7 to 7 are vertical sectional views showing other embodiments. In the figure, 1 is a discharge tube, 2 is a laser medium gas, 3A, 3B, 12A, 12B, 12C and 12 are electrodes, 4 is an AC power supply, 5 is a silent discharge, 6 is a total reflection mirror, 7 is a partially transmission mirror, 8 is laser light, 1
1, 11A, 11B and 11C are high permittivity dielectrics, 13, 13A, 13B and 13C are low permittivity dielectrics, 14 is a 3-phase AC power supply, 15, 16 are 2
A phase alternating current power source, 17 a low melting point glass, and 18 a dielectric plate with good thermal conductivity. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In a device that generates laser light and includes a discharge tube formed of a dielectric, an electrode provided on the outside of the discharge tube, and an AC power source connected to the electrode, The cross-sectional member of the discharge tube as seen is divided into six or more pieces with alternately adjacent high-permittivity dielectrics and low-permittivity dielectrics, and an alternating current is applied to the electrodes provided on the outside of the high-permittivity dielectric. An axial flow type silent discharge excited gas laser device characterized by applying a voltage. 2. The axial flow type silent device according to claim 1, characterized in that the discharge tube is divided into six parts, and a three-phase AC voltage is applied to electrodes provided on the outside of three opposing high-permittivity dielectrics. Discharge excited gas laser device. 3. The axial flow type silent device according to claim 1, characterized in that the discharge tube is divided into eight parts and a two-phase AC voltage is applied to electrodes provided on the outside of two opposing sets of high permittivity dielectrics. Discharge excited gas laser device. 4. The axial silent discharge excited gas laser device according to claim 1, wherein the high-permittivity dielectric and the low-permittivity dielectric are formed of planar members. 5. The axial flow type silent discharge excited gas laser according to claim 1, characterized in that the high dielectric constant dielectric is made of titanium oxide, the low dielectric constant dielectric is made of glass, and the boundary is bonded with low melting point glass. Device. 6. The axial flow type silent discharge excited gas laser device according to claim 5, characterized in that the low melting point glass of the boundary is raised on the outside. 7. Claim No. 7, characterized in that a plate made of a dielectric material with good thermal conductivity is sandwiched between a high-permittivity dielectric material and a low-permittivity dielectric material, and is protruded to the inside or outside of the discharge tube. The axial flow type silent discharge excited gas laser device according to item 1.