JPH0380586A - Evacuation tube of fast axial-flow type laser oscillator - Google Patents

Abstract

PURPOSE:To prevent discharge within an evacuation tube for relatively a long time with a simple structure by enabling laser gas to pass through the central part of a glass tube which is provided between a cathode and a heat exchanger and by providing a metal member consisting of a plurality of division channels which are equipped with a large number of surfaces. CONSTITUTION:A honeycomb shaped metal member 29 consisting of aluminum, etc., is provided at an evacuation tube 17 along gas flow at the central part of a glass tube 27. The honeycomb shaped metal member 29 with a relatively small frictional resistance of gas flow and a large contact area with gas flow is used.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an exhaust pipe for a high-speed axial flow laser oscillator.

(Prior Art) FIG. 3 shows the general structure of a conventional high-speed axial flow type carbon dioxide laser oscillator 1. That is, an inlet 5 for laser gas is provided at one end of the discharge tube 3, an outlet 7 is provided at the other end, an anode 9 is provided in the inlet 5, a cathode 1 is provided in the outlet 7,
Each is provided.

A high voltage DC power supply 13 is provided between the anode 9 and the cathode 11. In addition, an air supply pipe 15 is connected to the inflow part 5, and an exhaust pipe 17 is connected to the discharge part 7, and a heat exchanger and a blower 21 are provided between them. The laser gas G, which has become high in temperature due to discharge, is cooled down and circulated as shown by the arrow.

Further, a front mirror 23 and a rear mirror 25 are provided at the left and right ends of the discharge tube 3, respectively, and emit laser light excited in the plasma portion shown by diagonal lines in the direction indicated by the arrow.

In such a high-speed axial flow type carbon dioxide laser oscillator, during discharge, the cathode 11 is exposed to the collision (
(sputtering) to release the atoms that make up the cathode material. These atoms ride the gas flow, are oxidized, and adhere to the wall of the downstream exhaust pipe 17, and as the oscillator is used, they come to form thin aS. Since this thin aS is inherently conductive, it reduces the electrical resistance between the cathode 11 and one of the heat exchangers, allowing discharge to occur between them via the thin film S.

This discharge is completely unnecessary for the laser oscillator, and makes laser oscillation unstable, increases the temperature of the laser gas, and lowers the power conversion efficiency of the oscillator. For this reason, conventionally, the exhaust pipe has been lengthened, and the exhaust pipe has been replaced, cleaned, etc. in accordance with the usage time of the oscillator.

(Problems to be Solved by the Invention) As mentioned above, in order to prevent discharge in the exhaust pipe due to cathode sputtering, the exhaust pipe is generally made longer, but this has the problem of increasing the size of the device. Furthermore, it was not always easy to replace or clean the exhaust pipe. This invention was created with attention to such problems, and an object of the present invention is to provide an exhaust pipe for a high-speed axial flow laser oscillator that can prevent discharge within the exhaust pipe for a relatively long period of time. It is something.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the exhaust pipe of the present invention injects laser gas into the intermediate part of the glass tube provided between the cathode and the heat exchanger. It is provided with a metal member consisting of a plurality of divided passages that are free to pass through and have multiple surfaces.

(Function) With this structure, the laser gas traveling from the cathode to the heat exchanger passes through a metal member with relatively low frictional resistance provided in the middle of the glass tube. This laser gas contains the cathode oxide as described above, and this oxide concentrates on the metal member because the metal member has a large surface area and is a conductor. Therefore, since the adhesion to the glass tube is relatively reduced, the insulation resistance of the exhaust pipe is maintained for a relatively long period of time.

(Example) Next, an example of the present invention will be described based on the drawings. FIG. 1 shows one embodiment of this invention. As shown in the figure, this exhaust pipe 17 has a honeycomb-shaped metal member 29 made of aluminum or the like installed in the middle part of a glass tube 27 along the gas flow. This honeycomb-shaped metal member 29 has relatively little frictional resistance against the gas flow, and has an extremely large contact area with the gas flow.

Generally, the cathode oxide floating in the gas flow is more likely to adhere to the metal members of the conductor than the glass tube, so the cathode oxide concentrates on the two metal members.

Therefore, since the amount of ink adhering to the glass tube 27 is reduced, the insulation resistance of the exhaust pipe 17 can be maintained for a relatively long period of time.

FIG. 2 shows another embodiment in which the glass tube of the exhaust pipe 17 is divided into an upstream section 27-1 and a downstream section 27-2, and a honeycomb-shaped metal member 29 is inserted between the sections. This makes it easy to replace the two metal parts, and
Since the metal member is relatively cooled, the cathode material is more likely to adhere to it. Furthermore, replacement of glass tubes 27-1 and 27-2,
Cleaning etc. will also become easier.

In these examples, a honeycomb-shaped metal member such as aluminum is used, but the metal member is not limited to a honeycomb shape, and other shapes can be used as long as they have low frictional resistance and a large surface area. But that's fine.

[Effects of the Invention] As understood from the above description, since the present invention has the configuration described in the claims, it is possible to prevent discharge in the exhaust pipe over a long period of time. therefore,
The oscillator can be operated stably for a long period of time. Furthermore, since the structure of the exhaust pipe is extremely simple and compact, the oscillator can also be made compact.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the exhaust pipe of the present invention, FIG. 2 is a sectional view of another embodiment, and FIG. 3 is an explanatory diagram of a general high-speed axial flow type carbon dioxide laser oscillator. The same reference numerals in the figures represent the same or equivalent items. Explanation of symbols representing main parts of the drawings 1...High-speed axial flow type carbon dioxide laser oscillator 3...Discharge tube 11...Cathode 17...Exhaust pipe 1
9... Heat exchanger 27. 27-1. 2...Glass tube 9...Honeycomb-shaped metal member

Claims (1)

[Claims] In the middle of the glass tube between the cathode and the heat exchanger,
An exhaust pipe for a high-speed axial flow laser oscillator, characterized in that it allows laser gas to freely pass therethrough and is provided with a metal member consisting of a plurality of divided passages each having a large number of surfaces.