JPS60121787A - Silent discharge type gas laser device - Google Patents

Abstract

PURPOSE:To obtain a silent discharge type gas laser device capable of uniformly cooling a discharge tube by interposing and flowing a liquefied dielectric between the discharge tube and an electrode. CONSTITUTION:A pair of electrodes 2, 3 consisting of a metal are arranged at some interval among the electrodes 2, 3 and the outer wall of a tubular discharge tube 1, and mounted oppositely in the diametral direction of the discharge tube 1, a cooling tube 20 is fitted so as to surround the discharge tube 1 and the electrodes 2, 3, and a liquefied dielectric such as pure water 23 flows in the cooling tube 20. The outer wall of the discharge tube 1 and the electrodes 2, 3 are not fast stuck and some clearances are formed, and pure water 23 flows in the clearances. Accordingly, a silent discharge type gas laser device can cool the discharge tube 1 approximately uniformly because it is constituted so that pure water 23 directly flows on the outer circumference of the discharge tube 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to improvements in a discharge tube cooling means and electrode structure in a silent discharge gas laser device.

[Prior art]

Previously, this was the first silent discharge gas laser device manufactured by Sugi.
There was something shown in the figure. Fig. 1(a) is a sectional view showing the schematic configuration of a conventional silent discharge type gas laser device, and Fig. 1(b)
) is A of the silent discharge gas laser device in wJ1 figure (a).
- It is a sectional view along the A line. In each of the above figures, 1 is a tubular discharge tube made of a dielectric material, and 2 and 3 are metal tubes that are in close contact with the outer wall of the discharge tube 1 and are opposite to each other in the radial direction of the discharge tube 1. 4 is a pair of electrodes 2,
These are high frequency power supplies connected to 3, respectively. Reference numeral 5 indicates a total reflection mirror, and reference numeral 6 indicates a partial reflection mirror, each of which is attached to opposite ends of the discharge tube l in the longitudinal direction.
Laser light is oscillated in the direction indicated by 1. The vent pipe 1 is cyclically connected to each air pipe 7, 8 having a blower (B) 9 and a heat exchanger 10 therein. FIG. 1(b) shows the discharge that occurs when the high frequency power source 4 applies alternating voltage and pressure to the pair of electrodes 2 and 3.

Next, the operation of the conventional silent discharge type gas laser device shown in FIGS. 1(a) and 1(b) will be explained using a CO2 laser device as an example. Inside the discharge tube 1, CO2゜He,
A mixed gas such as N2 is filled at a pressure of several tens of Torr. In this discharge tube 1, when an AC voltage is applied from a high frequency power source 4 to a pair of electrodes 2.3, a silent discharge occurs within the discharge WI, and as a result, this silent discharge
The co2 molecules are excited, and laser oscillation occurs within a laser beam resonator made up of a total reflection mirror 5 and a partial reflection mirror 6.

Then, a part of the generated laser light is taken out to the outside through the partial reflecting mirror 6 as shown by the arrow 11 in FIG. 1(a). When the gas temperature rises due to silent discharge inside the discharge tube 1, the laser output decreases, so the gas is circulated by the blower (B) 9 and cooled by the heat exchanger 1o. is maintained below a predetermined value.

The conventional silent discharge gas laser device is constructed as described above, and has a structure in which a pair of electrodes 2 and 3 are provided in close contact with the outer wall of the discharge tube 1, so cooling of the discharge tube 1 is performed by the pair of electrodes 2 and 3. This has to be done indirectly via the electrodes 2 and 3, which has the disadvantage that it is extremely difficult to uniformly cool the discharge tube 1.

In addition, discharge tends to concentrate at the ends of each of the paired electrodes 2 and 3, resulting in non-uniform heat input, and as a result, there is a drawback that the discharge tube 1 is easily damaged.

[Summary of the invention]

This invention was made with the aim of improving the drawbacks of the conventional ones as described above, and has a structure in which a liquid dielectric material is interposed between the discharge tube and the electrodes to allow uniform cooling of the discharge tube.
It is an object of the present invention to provide a highly reliable silent discharge type gas laser device that can prevent the electric field from concentrating at the end of the electrode.

[Implementation sequence of the invention]

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

FIG. 2 is a cross-sectional view showing an electrode structure used in a silent discharge gas laser device according to an embodiment of the present invention. In the figure, 1 is a tubular concentric tube made of a dielectric material, 2 and 3 are arranged with a gap between them and the outer wall of the discharge tube 1, and are arranged so as to face each other in the radial direction of the discharge tube 1. A pair of electrodes made of metal are provided, 20 is a discharge tube 1 and a pair of electrodes 2,
A cooling pipe 23 is provided to surround the cooling pipe 2o.
A liquid dielectric, e.g. pure water, flows therein, 21. 22 is an inlet and an outlet for the pure water 23. The outer wall of the discharge tube 1 and the pair of electrodes 2 and 3 are arranged with a certain gap, for example, about 1 mm, without being in close contact with each other, and pure water 23 is allowed to flow through this gap. It is configured to do so.

According to the silent concentric type gas laser device of the present invention, the above-mentioned tub is configured so that the pure water 23 flows directly around the outer periphery of the discharge tube 1, so that the convex tube 1 can be cooled to almost one tube. becomes possible. Further, since it is no longer necessary to provide the pair of electrodes 2, 3 in close contact with the outer wall of the discharge tube 1, the -1 pair of electrodes 2, 3 can be formed in any shape and structure.

3 and 4 are cross-sectional views showing the electrode structure used in a silent discharge gas laser device, which is another embodiment of the present invention, and the same parts as in FIG. 2 are indicated by the same reference numerals. The detailed explanation will be omitted. The one shown in FIG. 3 has a structure in which the pair of electrodes 2.3 are formed in such a shape that the ends of the electrodes are gently moved away from the outer periphery of the discharge tube 1. In the pair of electrodes 2 and 3, it is difficult to prevent the electric field from concentrating at the ends of the electrodes, so that damage to the discharge tube 1 can be effectively reduced.

Moreover, what is shown in FIG. 4 is a case where a pair of metal mesh electrodes 31 and 32 formed of metal mesh are used as the structure of the pair of electrodes 2.3. In the pair of metal mesh electrodes 31 and 32 having such a structure, the pure water 23 flows through the gap between the respective metal meshes to uniformly cool the discharge tube 1, so that the cooling effect on the discharge tube 1 is further enhanced. increase

FIGS. 5(a) and 5(b) are explanatory diagrams showing equivalent circuits of electrode portions used in the silent discharge type gas laser apparatus shown in FIGS. 1 and 2, respectively. In the equivalent circuit in the conventional example shown in FIG. 5(a), input power Wd.

is expressed by the following equation (1).

Wd, = 4f Cd V* (VOI) −V*
) "'-""<1 However, Wd is input power CW
I and f are the four-source frequency [''/s], Cd is the capacitance t [F] of the discharge tube, and V* is the discharge voltage [V] of Zener diodes connected in anti-series.

Vop is the peak value [v] of the applied voltage.

On the other hand, in the equivalent circuit according to the present invention shown in FIG. Since pure water 23 is flowing through the pipe, the capacitance Cw of the pure water 23 is inserted in series with the capacitance cd of the discharge tube, and the input power Wd2 is expressed by the following equation (2). expressed.

eff C" Cd However, Cd=o;+.4 By the way, the dielectric constant of pure water 23 is 8o, which is about an order of magnitude higher than that of a normal dielectric, so <f f is the value of the discharge tube. It is not much smaller than the capacitance Cd, and therefore, judging from equations (1) and (2) above, the pure water 23 is connected between the discharge tube 1 and the pair of electrodes 2 and 3. Even if it flows through gap 2,
A significant decrease in input power wd2 can be avoided.

Here, Co shown in FIGS. 5(a) and 5(b) represents the gas capacitance [F] within the discharge tube 1.

In the above embodiment, a case was explained in which pure water 23 was used as the liquid dielectric, but as long as it is a liquid dielectric, for example, chlorofluorocarbons, oil, etc. may be used, and basically the same method as in the above embodiment may be used. be effective.

In this case, from the viewpoint of power input, the gap 1 between the vent tube 1 and the pair of electrodes 2.3 may be appropriately set to an optimum value.

〔Effect of the invention〕

As explained above, this invention uses a sliding electric current that circulates through a liquid dielectric between the discharge tube and the electrode in conjunction with a silent discharge type gas laser device, so that the discharge tube can be cooled extremely uniformly. There is an effect that can be done. However, since the shape and structure of the polarization can be configured arbitrarily, it is possible to prevent the concentration of the d field at the extremes2, making it possible to create a highly reliable silent discharge gas laser device. This has the excellent effect of reducing

[Brief Description of the Drawings] Fig. 1(a) is a sectional view schematically showing the sliding operation of a conventional silent discharge type gas laser device, and Fig. 1(b) is a sectional view of the silent discharge type 4 gas laser device of Fig. 1(a). Sectional view of the device along line A-A, second
The figure is a sectional view showing the electrode structure used in a silent discharge type gas laser device, which is one embodiment of the present invention, and Figures 3 and 4 are silent discharge type gas laser devices, which are other embodiments of the present invention. A cross-sectional view showing a quadrupole structure used in a gas laser device,
FIGS. 5(a) and 5(b) are explanatory diagrams showing equivalent circuits of electrode portions used in the silent discharge type gas laser apparatus shown in FIGS. 1 and 2, respectively. In the figure, 1... A concentric tube, 2, 3... A pair of electrodes, 4... A high frequency power source, 5... A total reflection mirror, 6... A partial reflection mirror, 7.8... A transmitting mirror. Trachea, 9...Blower (B)
, 10...-heat exchanger, 11...-arrow, 20...-cooling pipe, 21.22...-inlet and outlet, 23...-pure water, 31.32...-pair of metal mesh electrodes It is. In each figure, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 (b) Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] +1) An AC voltage is applied to a pair of electrodes on the outer wall of a tubular radiation IAt tube made of a dielectric material, and radiation is caused in the radiation tube.
What is claimed is: 1. A silent discharge type gas laser device, characterized in that a liquid dielectric material is interposed between the discharge tube and the electrode, in the device for generating temperature of laser light by causing the discharge tube to heat up. (2) As the liquid dielectric, pure water, other fluorocarbons,
The silent discharge type gas laser device according to claim 1, characterized in that oil or the like is used. (3) The silent discharge type gas laser device according to claim 1, wherein the electrode end portion is formed in a shape that gradually moves away from the outer periphery of the discharge tube when td < i +. (4) The silent discharge type gas laser device according to claim 1 or 3, wherein the electrode uses a metal mesh.