JPS625675A - Gas laser device - Google Patents

Abstract

PURPOSE:To obtain a large output by feeding a laser medium gas into a discharge tube with an interval between the first cylinder and the second cylinder of substantially the same axis as the tube as gas feeding gap, thereby increasing gas flow rate to obtain a stable glow discharge even with large discharge power. CONSTITUTION:A structure that laser medium gas flows into a discharge tube 1 is formed, the first cylinder 11 of substantially the same axis as the tube 1 is formed at the portion for feeding the gas to the tube, and the second cylinder 15 of substantially the same axis as the first cylinder 11 is formed at an interval 14 form the first cylinder 11. A gap 14 between the cylinder 11 and the cylinder 15 is formed to feed the gas to the tube 1 as gas feeding gap. Further, a cylindrical discharging electrode 16 having an inner diameter D2 larger than the diameter D1 of the outer periphery of the cylinder 11 is disposed substantially coaxially with the cylinder 11. Thus, a discharging current is increased in the glow discharge stable state to increase the laser output.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in the gas laser family (a) using electric discharge.

Conventional gas laser devices fill a discharge tube with a medium gas such as carbon dioxide gas, nitrogen gas, helium gas, etc., and an anode installed in the discharge tube.
A common method is to generate a glow discharge in the dark to excite the laser medium gas and oscillate the laser beam. Further, the temperature of the laser medium gas increases due to discharge, and the upper temperature limit reduces the laser output. Is it possible to remove the laser medium gas using a blower or the like? The temperature of the laser medium gas is strongly prevented by allowing it to pass through the tube at high speed. The temperature of the laser medium gas increases in proportion to the electrical energy involved in the discharge, and decreases in proportion to the gas flow rate passing through the discharge tube.

Laser output (increases in proportion to the energy input into the discharge and decreases in inverse proportion to the gas temperature. Therefore, as the discharge energy increases, the laser output increases, but the laser gas temperature rises. The output becomes saturated as a result.By increasing the flow of gas passing through the discharge tube, the rise in gas temperature can be suppressed, the input discharge energy can be increased, and the laser output can be increased.

Forced cooling gas laser devices such as L are divided into several types depending on the direction of the laser optical axis, gas flow direction, and discharge direction. A gas stream flowing at high speed in the direction of
It is called a high-speed axial flow laser. High-speed axial flow lasers have been put into practical use for processing such as precision cutting because the laser intensity (i) is axially symmetrical and the efficiency is high.

Problems to be Solved by the Invention In order to increase the output of a high-speed axial flow laser, it is necessary to increase the gas flow interval and increase the glow discharge injection power as described above. For this reason, conventionally, the discharge current has been increased to increase the discharge injection power. However, discharge forms generally include glow discharge and 7-way discharge, and as the discharge current increases, glow discharge becomes unstable and shifts to arc discharge.

Arc discharge concentrates, causing a rapid increase in gas temperature and a rapid decrease in laser output. Especially on the electric harvesting surface, glow discharge concentrates locally, making the discharge even more unstable.
This will substantially prevent an increase in laser output. In particular, as the gas flow distance is increased, the gas flow velocity distribution on the electrode discharge surface becomes uneven, resulting in local pressure non-uniformity.

A local decrease in gas pressure causes the discharge to concentrate and the concentrated discharge leads to a local increase in gas temperature. As a result, the gas density further decreases locally, and t! Therefore, increasing the gas flow distance to increase the glow discharge injection force has been limited by the instability of the glow IIi electric current. When making a popular curry bottle, this was achieved by increasing the number of discharge tubes.

The present invention aims to increase the gas flow rate, obtain stable IC laser discharge even at large discharge injection power, and promote a high output gas laser device.

Means for Solving the Problems The gas laser device of the present invention is configured to allow a laser medium gas to flow into a discharge tube, and has a part that introduces the laser medium gas into the discharge tube substantially coaxially with the discharge tube. 1st
Provide a cylindrical body u1 with a certain gap between the first cylindrical body and the second cylindrical body of the IC11 axis, and connect the first cylindrical body and the second cylindrical body. The gap between the cylinders is configured to be used as a gas introduction gap to introduce the medium gas into the discharge tube, and the external cause of the first cylindrical body (having an inner diameter larger than It is characterized in that the cylindrical discharge electrode is disposed approximately coaxially with the first cylindrical body.

Further, the gas laser device of the present invention is characterized in that the cylindrical discharge electrode is provided as described above, and both end surfaces of the cylindrical discharge N electrode except for the circular surface parallel to the gas flow are covered with an insulating material.

Effect: With this configuration, the laser medium gas is introduced into the discharge tube through the gap formed between the first and second cylindrical bodies, which are substantially coaxial with the discharge tube, and these two cylinder bodies. The flow velocity is at its maximum when passing through the gap formed by the first cylinder and the second cylinder, and since the discharge electrode is placed downstream of this gap where the gas flow is high, the discharge at the electrode is I can concentrate on the direction. As a result, the discharge area can be reduced, and ye'll due to non-uniformity of local gas pressure can be reduced. Gas whose temperature has locally risen can be removed from the electrode surface in a short period of time. Moreover, since the gas flow path expands when it flows into the vicinity of the electrode from the gap, the lake gas is rapidly cooled due to adiabatic expansion, and local gas temperature can be prevented from increasing. The effect of the invention can be increased and the discharge injection power can be increased.

In addition, glow discharge is stabilized by covering both end faces of the cylindrical discharge electrode with an insulating material except for the circular surface parallel to the gas flow.

Example Hereinafter, the present invention will be explained according to one embodiment. .

FIG. 1 shows the overall configuration of a high-speed axial flow gas laser device according to the present invention. A discharge tube 1 has electrodes 2 at both ends, and a DC high voltage power source 3 for generating glow lightning is connected between the electrodes 2.

Inside the discharge tube 1, a mixed gas of carbon dioxide gas, N-cord gas, helium gas, etc. is flowing by a blower 4.

At each end of the rIi tube 1 there is a reflection v constituting an optical resonator.
L5 and output mirror 6 are arranged. The blower 4 creates a flow of laser medium gas into the discharge tube 1 through the connecting tube 7. The laser medium gas is heated by discharge in the discharge tube 1 and enters the blower 4 through the heat converter 8. Blower 4
The laser gas is compressed. If the heat generated by compression is large, a heat converter 9 is provided. As for the laser gas, an arrow 10 indicates the direction of circulation of the laser medium gas.

Figure 2 shows the blower 4 in the gas laser device of Figure 1.
shows a cross-sectional view of the vicinity where the laser medium gas is fed into the discharge tube 1, and the laser medium gas flows through the connecting tube 7. The laser medium gas flowing from the connecting pipe 7 does not flow directly into the discharge @1, but rather between the first insulating cylindrical body 11 disposed approximately coaxially with the M electric tube 1 and the laser medium gas introduction block 12. It passes through the space 13 formed between them. The first cylindrical body 11 is made of a glass cylinder, ceramic, or the like.

4 near the end of the first cylindrical body 11 on the side of the b-shaped Ti tube 1.
The second cylindrical body 15 is arranged with a predetermined gap 14 between the outer periphery of the first cylindrical body 11 and the second cylindrical body 15 . The laser medium gas flows into the discharge tube 1 at high speed through this gap 14.

Furthermore, a cylindrical electrode 16 with an inner diameter D2 larger than the outer diameter D1 of the first cylindrical body 11 is located near the downstream side of this gap 14.
is provided coaxially with the first cylindrical body 11.

With this configuration, the laser medium gas flow is divided into the first and second
Since the gas flows through the gap 14 formed between the cylindrical bodies 11 and 15, a uniform gas flow is obtained. Moreover, all the laser gas flowing into the discharge tube 1 can pass through this gap 14, and the gas flow on the electrode surface can be increased. Thereby, the discharge area on the electrode surface can be limited to the downstream side of the gas flow, and the instability of glow discharge due to non-uniformity of the gas flow can be solved.

In addition, since the laser medium gas is expanded through the gap 14 and flows into the discharge tube 1, the gas is rapidly cooled due to predetermined thermal expansion, thereby preventing an uneven temperature upper limit.

FIG. 3 shows another embodiment, in which parts having the same functions as those in FIG. 2 are given the same reference numerals. In this figure 3,
Both end surfaces of the cylindrical electrode 16 except for the circular surface (A) parallel to the gas flow are covered with an insulator 17, thereby further localizing the glow discharge and making the glow discharge more stable.

As described in the detailed description of the invention, the gaslade device of the present invention includes a first cylindrical body substantially coaxial with the central axis of the discharge tube, and a first cylindrical body with a predetermined gap provided between the outer periphery of the first cylindrical body and the first cylindrical body. The second almost coaxial with
Since the laser medium gas flows through the gap between the cylindrical body and the cylindrical body, all of the laser medium gas flowing into the discharge tube flows through this gap, so the gas can flow at high speed over the electrode surface, and the discharge at the cylindrical electrode surface. The area can be reduced by limiting the area downstream of the gas.

Thereby, the influence of local gas pressure non-uniformity at the electrode can be reduced. In addition, gas whose temperature has locally increased can be removed from the electrode surface in a short period of time, and it can be prevented from growing due to temperature drop due to arc transfer. This will give you glow t! It is possible to increase the laser output by increasing the discharge injection current in a stable state.

With this configuration, the saturation power per discharge is 1
~3kw was reduced to 10 to 20kv in the present invention.
It is possible to increase the laser output to 100-300W.
kW to 2 kW can be obtained.

Furthermore, the smaller the cylindrical electrode is, for example by covering both end surfaces of the cylindrical electrode except for the circular surface parallel to the gas flow with an insulating material, the more stable the reglow discharge will be.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of an embodiment of the gas laser device of the present invention, and FIGS. 2 and 3 are enlarged sectional views of the parts shown in FIG. 1 in the first and second inventions, respectively. DESCRIPTION OF SYMBOLS 1...tIl electric tube, 4...B [J war, 5...Reflector, 6...Output mirror, 7...Connecting tube, 10...Circulation direction of laser medium gas, 11 ...first cylindrical body, 1
2...Laser medium gas introduction block f]tsuk, 14...Gap, 15...Second cylindrical body, 16...Cylindrical electrode, 1
1... Insulator agent Yoshihiro Morimoto Figure 1ゝ4 @Figure 2'l

Claims (1)

[Scope of Claims] 1. A first cylindrical body is configured to flow a laser medium gas into the discharge tube, and a first cylindrical body substantially coaxial with the discharge tube is provided at a portion where the laser medium gas is introduced into the discharge tube. A second cylindrical body substantially coaxial with the first cylindrical body is provided at a certain gap from the first cylindrical body, and the gap between the first cylindrical body and the second cylindrical body is used as a gas introduction gap. A cylindrical discharge electrode configured to introduce a laser medium gas into the discharge tube and having an inner diameter larger than an outer circumferential diameter of the first cylindrical body on the downstream side of the gas introduction gap is substantially coaxial with the first cylindrical body. Gas laser equipment installed. 2. The structure is such that a laser medium gas flows into the discharge tube, and a first cylindrical body substantially coaxial with the discharge tube is provided at a portion where the laser medium gas is introduced into the discharge tube, and the first cylindrical body and A second cylindrical body substantially coaxial with the first cylindrical body is provided with a certain gap therebetween, and the gap between the first cylindrical body and the second cylindrical body is used as a gas introduction gap to introduce laser medium gas into the discharge tube. A cylindrical discharge electrode having an inner diameter larger than the outer circumferential diameter of the first cylindrical body is disposed on the downstream side of the gas introduction gap substantially coaxially with the first cylindrical body, and the cylindrical discharge A gas laser device in which both ends of the electrode, except for the circular surface parallel to the gas flow, are covered with an insulating material.