JPS611071A - Gas laser generator - Google Patents

Abstract

PURPOSE:To prevent electrodes, discharge tube wall and a circulating path substance from deteriorating by providing a gas exhaust valve and a gas supply valve in the circulating path of laser gas. CONSTITUTION:Valves 14, 15, 19 are closed to circulate laser gas by a blower 9 in a passage 8. The laser gas is activated, and reaction with the electrodes, the inner wall of the passage of the tube 1 become reversible to hole an equilibrium state. When the operation is stopped, the valve 14 is simultaneously opened, and ionized laser gas in the passage 8 is exhausted by a pump 16 out of the system. Thus, after stopping, the reaction and adsorption between the ionized gas and the electrodes, the tube 1 and the inner wall of the passage 8 are avoided to prevent them from deteriorating. After evacuating in vacuum, the valve 14 is closed, the valves 15, 19 are opened, fresh laser gas of atmospheric pressure or higher is filled from a bomb 17 in the passage 8, and when exceeding the prescribed pressure, the valve 20 is operated to stop supplying the gas. With this construction, a gas laser device which can continue stable blow discharge is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a gas laser generator, and particularly to a gas laser that uses glow discharge as a laser oscillation excitation source.

Conventional Structures and Their Problems In laser generators using gaseous substances as laser media, it is generally practiced to use glow discharge as an excitation source to generate a negative temperature distribution in the medium.

However, when a gas medium is subjected to glow discharge, the gas medium becomes ionized and reacts with not only the electrodes and the walls of the discharge tube, but also the gas circulation path and the substances that make up the system.
Or it may be adsorbed.

This phenomenon does not significantly affect the discharge state of glow discharge because the reaction and adsorption/desorption are reversible and a constant equilibrium state is maintained during glow discharge.

However, after the operation has been stopped, the ionized gas substances continue to undergo irreversible reactions with the electrodes and the walls of the discharge tube as well as with the gas circulation path materials, or are adsorbed. What is most adversely affected by this adsorption is the electrode for maintaining glow discharge.

In other words, the adsorption of ionized gas substances on the electrodes has a negative effect on the stability of glow discharge immediately after the start of operation, and as a result, the laser output immediately after the start of operation is
As shown by the broken line B in the figure, there was a problem with the characteristics that it became unstable and took a long time to stabilize.

OBJECTS OF THE INVENTION An object of the present invention is to provide a gas laser generator capable of solving the above conventional problems and sustaining stable glow discharge.

Structure of the Invention The gas laser generator of the present invention includes a first on-off valve in a laser gas circulation path for discharging the laser gas after the operation is stopped, and a first opening/closing valve for supplying fresh laser gas to the circulation path after the laser gas is discharged. 2 on-off valves and a constant pressure valve for adjusting the pressure of the supplied laser gas to a predetermined value.

The effect of this configuration is as follows. That is, after the operation is stopped (preferably immediately after the stop), the first on-off valve is opened to discharge the ionized laser gas in the circulation path. This evacuation is preferably completed by vacuum suction using a vacuum pump. This discharge avoids reaction and adsorption of the ionized laser gas with the electrodes, discharge tube walls, and gas circulation path materials.

Then, after the laser gas is discharged (preferably immediately after the discharge), the first on-off valve is closed, and the second on-off valve is opened to supply fresh laser gas into the circulation path. This prevents air from entering the circulation path.

If the laser gas is continuously supplied into the circulation path, when the pressure reaches a certain level or higher, the constant pressure valve operates, and the pressure within the circulation path is maintained at a predetermined value. Needless to say, the gas pressure at this time is set within a range suitable for laser generation.

In this way, a gas laser generator filled with fresh laser gas at a predetermined pressure has less deterioration of its electrodes, discharge tube walls, and circulation path materials, so the laser output rise characteristics are fast and stable at the start of operation. becomes.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a configuration diagram of a carbon dioxide laser generator as an example.

In this figure, there are two discharge tubes 1 made of an insulating material such as glass for generating a glow discharge for laser amplification. The anode part 2 is common to both electric tubes 1.1, and a cathode part 3.3 is arranged opposite to the anode part 2.

Gas inlets 4, 4 are connected to the cathode section 3.3, and a gas outlet 5 is provided at the anode section 2.

A reflecting mirror 6.7 is arranged to sandwich the discharge tube 1.1,
It constitutes an optical resonator. The reflecting mirror 6 that takes out the laser output is called an output mirror, and the other reflecting mirrors 7 are generally concave reflecting mirrors.

The laser medium gas is circulated by a blower 9 or the like through a circulation path 8.8, and is circulated through the discharge tube 1. 1 to form a flow. The positive output terminal of the DC power supply 10 is connected to the anode part 3, and the negative output terminal is connected to the cathode parts 3, 3 via stabilizing resistors 11.11 and the like. It goes without saying that configuring a constant current circuit using a vacuum tube or the like instead of the stabilizing resistors 11' and 11 to maintain a constant discharge current is effective in improving the stability of glow discharge. stomach.

A first opening/closing valve 14. A second on-off valve 15 is provided, and a vacuum pump 16 . 17 to the laser gas cylinder.

A branch passage 18 is further connected to the branch passage 12, and this branch passage 18 is provided with a third on-off valve 19, and further a constant pressure valve 2.
0 is set.

The operation will be explained below. While the gas laser generator is operating,
All on-off valves 14, 15, and 19 are closed, and the laser gas is circulated in the circulation path 8 by the blower 9.

At this time, the circulating laser gas is ionized by glow discharge. However, it is constantly cycling and is energized by passing through the glow discharge again. Therefore, the laser gas is in an activated state, and reactions with the electrodes, the inner wall of the circulation path 8 of the discharge tube 1, etc. are reversible, and an equilibrium state is maintained.

Next, when the operation is stopped, the on-off valve 14 is immediately opened, and the ionized laser gas in the circulation path 8 is discharged to the outside of the system by the vacuum pump 16. By this operation, reaction and adsorption between the laser gas, which has been ionized after the operation is stopped, and the electrodes, the discharge tube 1, and the inner walls of the circulation path 8 can be avoided, and it is possible to prevent their deterioration.

After further evacuation, the on-off valve 14 is closed and the on-off valve 15.19 is opened to fill the circulation fWB with laser gas at atmospheric pressure or higher to prevent air from entering.

That is, when the circulation path 8 is filled with fresh laser gas from the pump 17 and the pressure in the circulation path B becomes equal to or higher than a predetermined value, the constant pressure valve 20 operates. The supply of laser gas is stopped based on the operation of the constant pressure valve 20.

The above operations are sequence controlled.

That is, ■ Operation stop detection ■ Opening of the first on-off valve 14 and activation of the vacuum pump 16 ■ Timer on ■ Closing of the first on-off valve 14 and stoppage of the vacuum pump 16 ■ Second on-off valve 15 and third on-off valve Opening of on-off valve 19 ■ Operation of constant pressure valve 20 ■ Closing of second on-off valve 15 and third on-off valve 19 is sequentially controlled.

Fig. 2 is a characteristic diagram showing the stability of the laser output immediately after the start of operation, and compared to the conventional characteristic B indicated by the dotted line, the characteristic A of the embodiment of the present invention is far superior and the laser output is stable. I can see that you are doing it.

Effects of the Invention According to this invention, electrodes and discharge tube walls are formed by reaction with or adsorption of ionized laser gas.

This has the effect of preventing deterioration of the circulation path material and making it possible to make the laser output rise quickly and stably at the start of operation.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, and FIG. 2 is a laser output characteristic diagram. 8... Circulation path, 14... First on-off valve, 15...
Second on-off valve, 20...Constant pressure valve Fig. 1 Fig. 2

Claims (1)

[Claims] A first on-off valve for discharging the laser gas after the operation is stopped in the laser gas circulation path, a second on-off valve for supplying fresh laser gas to the circulation path after the laser gas is exhausted, and a pressure of the supplied laser gas. A gas laser generator equipped with a constant pressure valve to set the value to a predetermined value.