JPS62204585A - Gas laser - Google Patents

Abstract

PURPOSE:To realize a uniform glow discharge even in a high barometric pressure and to apply the glow discharge to an axial-flow gas laser using a blower of a small pressure head as well by a method wherein the gas laser is constituted in such a structure that a partition plate is provided in the gas introducing part, an electrode is provided in the space on the up stream side of the gas flow and the gas flow flowing on the down stream side is directly sprayed on the glow discharge. CONSTITUTION:A partition plate 10, an anode 5 and an electrode 11 are provided at the gas introducing part. The space of the gas introducing part is splitted into a space near a cathode 4 and a space far from the cathode 4 by the partition plate 10. A gas flow 12 is divided into a gas flow 13 to flow along the vicinity of the anode 5 and a gas flow 14 to be directly sprayed on a glow discharge by the partition plate 10. The anode 5 is constituted of a meanderingly crawled metal wire for spreading the glow discharge and is slanted in the direction of the central axis of a discharge tube 1. Only the gas flow 13 that flows along the vicinity of the anode 5 is pre-ionized by a glow discharge 18 that is generated between the electrode 11 and the cathode supporting rod by a high-voltage power supply 17 and the gas flow 14 to be directly sprayed on a glow discharge 7 is so contrived as not to be pre- ionized. As a result the diffusion of the glow discharge 7 in the vicinity of the anode 5 can be promoted without decreasing the diffusion of the glow discharge by the gas flow 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas laser device, and particularly to a discharge part structure suitable for high-pressure discharge when using a blower with a small pressure head such as a turbo blower.

[Conventional technology]

In an axial flow gas laser device, when the gas pressure is increased from 50 Torr to a high pressure of 100 Torr.

It becomes difficult to maintain uniform discharge, and as the injected power increases, it becomes easier to shift to arc discharge.

In order to keep the discharge uniform, conventional devices such as JP-A-60-7
In Japanese Patent No. 0786, the cross-sectional area of the gas flow path is increased near the anode, and the gas flow is rapidly expanded to quickly stir the plasma near the anode.

This was designed to prevent the transition to arc discharge.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, sufficient consideration is not given to the pressure loss that occurs due to the sudden expansion of the gas flow for stirring the glow discharge and the sudden contraction at the inlet of the discharge tube. When using a Roots blower with a large pressure head etc. as a blower for gas circulation, there is no particular problem, but when using a turbo blower etc. with a small pressure head, the laser output may decrease due to the reduction in gas flow rate due to the above pressure loss. There was a problem with decline.

An object of the present invention is to provide an electrode peripheral structure for high-pressure discharge that can be applied to a gas laser device using a blower with a small pressure head such as a turbo blower.

[Means for solving problems]

The above purpose is to make the cross-sectional area of the gas flow path almost constant for both the gas inlet and the discharge part, to provide a partition plate in the gas inlet to divide the space, and to create an electrode in the upstream space of the divided space. This is achieved by providing a configuration in which the gas flow flowing in the downstream space is directly blown onto the glow discharge from the side.

[Effect]

According to the present invention, a gas vortex is generated at the end of the partition plate provided in the gas introduction part and the downstream area thereof, and the glow discharge is spread along the partition plate, while the gas flow blows directly onto the glow discharge. This also works to stir the glow discharge and diffuse the glow discharge in the direction of the gas flow, thereby restricting the transition to an arc due to current concentration and achieving uniform glow discharge at high pressure.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. A total reflection mirror 2 is attached to one end of the discharge tube 1, and an output mirror 3 is attached to the other end. A glow discharge 7 is generated by a high voltage power supply 6 between a cathode 4 provided on the downstream side of the gas flow of the discharge tube 1 and an anode 5 provided within the gas inlet to the discharge tube 1 .

This glow discharge 7 excites the laser gas flowing inside the discharge tube 1, amplifies the laser light that is reflected back and forth between the total reflection mirror 2 and the output fi3, and extracts a part of it from the output mirror 3. The heated laser gas is cooled by a heat exchanger 8 and circulated by a blower 9. A partition plate 10 is provided at the gas introduction part to the discharge tube 1. An anode 5 and an electrode 11 are provided. FIG. 2 shows an enlarged view of this gas introduction section. Further, FIG. 3 shows the gas introduction section seen from the plane AA' in FIG. 2. The partition plate 11 separates the space of the gas introduction part from the cathode 4.
Divide into space close to and space far away. The anode 5 is placed in a space far from the cathode 4 in the divided space. Thereby, the gas flow 12 is divided by the partition plate 10 into a gas flow 13 flowing in the vicinity of the anode 5 and a gas flow 14 blowing directly onto the glow discharge.

When paying attention to the gas flow at the end of the partition plate 10, as shown in FIG. 4, the gas pressure decreases due to the gas flow in the portion 15 that is in the shadow of the gas flow, and the glow discharge itself spreads easily. This acts to spread the glow discharge along the edge of the partition plate 10, and generates a vortex 16 on the downstream side thereof, stirring the glow discharge 7. Further, the gas flow 14 directly blown onto the glow group t7 also serves to stir the glow discharge 7 and diffuse it in the flow direction.

In order to spread the glow discharge without obstructing the flow of the gas flow 13, the anode 5 is constructed of a meandering metal wire as shown in FIG. When the surface of the anode 5 was parallel to the central axis of the discharge tube 1, a phenomenon was observed in which current concentration occurred in the anode portion near the partition plate 10 and transitioned to arc discharge from there. 5 in the direction of the central axis of the discharge tube 1 (second
θ) in the figure, and by relaxing the local electric field concentration on the surface of the anode 5, a glow discharge could be generated from the entire surface of the anode 5. In other words, in particular, the anode 5 is made of meandering metal so as not to obstruct the gas flow 13, and is tilted toward the glow discharge 7 side with respect to the partition plate 10, so that a partial electric field on the surface of the anode 5 is formed. Concentration can be alleviated and uniform glow discharge can be obtained.

By ionizing the gas flow flowing into the discharge section in advance, glow discharge at high pressure can be facilitated. However, in this embodiment, if the entire gas flow 12 is pre-ionized, the diffusion of the glow discharge near the anode is promoted, but the diffusion due to the spraying of the gas flow 14 is reduced, and the goo discharge is biased (towards the bottom in FIG. 2). ) a phenomenon occurred. Therefore, as shown in this embodiment, only the gas flow 13 flowing near the anode 5 is pre-ionized by the glow discharge 18 generated between the electrode 11 and the anode support rod using the high-voltage type g17, and is directly applied to the glow group 117. As a result of preventing the sprayed gas flow 14 from pre-ionizing, it was possible to promote the diffusion of the glow discharge 7 in the vicinity of the anode 5 without reducing the diffusion caused by the gas flow 14.

As described above, according to this embodiment, the anode 5 is placed in the space far from the cathode 4 among the spaces divided by the partition plate 10.
, and the gas flowing in the space near the cathode 4 is directly blown onto the glow discharge 7, thereby making it possible to create a glow group fl!
7 can be stirred and diffused in the flow direction.

Further, according to this embodiment, by tilting the anode 5 in the direction of the central axis of the discharge tube 1, local electric field concentration on the surface of the anode 5 is alleviated, and glow discharge is generated from the entire surface of the anode 5. It has the effect of being able to.

Further, according to this embodiment, only the gas flowing into the space where the anode 5 is provided is pre-ionized on the upstream side, and the others are not pre-ionized, thereby reducing the diffusion caused by the gas flow directly blown onto the glow discharge. This has the effect of promoting the diffusion of glow discharge in the vicinity of the anode 5.

FIG. 5 shows another embodiment. Only the area around the gas introduction part is shown. The rest is the same as in Figure 1. In FIG. 5, parts having the same functions as those in FIG. 1 are denoted by the same numbers, and explanations thereof will be omitted. A feature of FIG. 5 is that the gas introduction section is configured axially symmetrically with respect to the central axis of the discharge tube 1.

In this embodiment, since the arrangement of the anode 1 and the flow of gas are axially symmetrical with respect to the central axis of the discharge tube 1, the glow discharge is also performed axially symmetrically, and the effect is that a glow discharge suitable for the laser device can be obtained. There is.

〔Effect of the invention〕

According to the present invention, the glow discharge near the anode can be diffused and stirred without providing sudden expansion or contraction in the gas flow path, and uniform glow discharge can be realized even at high pressure, so the pressure head is small. The present invention has the effect of providing an electrode peripheral structure for high-pressure discharge that can also be applied to an axial gas laser device using a blower.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
A partially enlarged view of the figure, Figure 3 is a sectional view taken along line A-A' in Figure 2,
FIG. 4 is a state diagram of the flow at the end of the partition plate, and FIG. 5 is a partial configuration diagram of a different embodiment.

Claims (1)

[Claims] 1. A first electrode is disposed in a discharge tube having mirrors at both ends, a mixed gas is introduced into the discharge tube from a gas inlet communicating with the discharge tube, and a first electrode is provided in the gas inlet. two electrodes and the first
A device for obtaining laser light by generating a glow discharge between the first electrode and the first electrode, characterized in that a partition plate is arranged to divide the space of the gas introduction part into at least two spaces, a space far from the first electrode and a space near the first electrode. gas laser equipment. 2. In the gas laser device described in item 1, the second electrode is located in the space far from the first electrode among the spaces divided by the partition plate.
A gas laser device characterized by being provided with an electrode. 3. In the gas laser device according to item 1 or 2,
The gas laser device is characterized in that the second electrode is made of meandering metal, and a portion remote from the partition plate is inclined in the direction of the central axis of the discharge tube. 4. In the gas laser device according to item 1 or 2,
A gas laser device characterized in that only the gas flowing through the space in which the second electrode is provided is pre-ionized on the gas flow upstream side of the second electrode, and the gas flow directly blown onto the glow discharge is not pre-ionized.