JPS6376388A - Starting of gas laser oscillator - Google Patents

Abstract

PURPOSE:To make it possible to obtain a glow discharge economically and surely by starting the discharge at a voltage lower than a constant one that is kept during an operation and after that, filling additionally a laser gas. CONSTITUTION:An inside of a wind tunnel is exhausted at a vacuum of around 1/1000 and a laser gas is filled up to a gas pressure of about 1/30 atm which is determined previously. Once a pressure sensor 16 detects what a gas filling is complete, its wind tunnel allows a discharge to start. Then the laser gas is additionally filled up to 1/20 atm. When it starts the discharge at around 1/30 atm in such a manner, a glow-discharge is uniformly distributed all over the surface of electrodes. After that, even though an additional filling of the laser gas is carried out, glow-lengths of every electrodes become shorter gradually at a uniform length and there is no extinction of arc. As a result, no glows are unevenly distributed toward electrodes and excitement of the laser gas is so uniformly carried out that its state permits gain of laser oscillations to be equal spatially so as to obtain light of a good quality.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a starting method for discharge excitation of a high-output gas laser oscillator used in drilling, welding, hardening, cutting, etc. Regarding.

(Prior art) There are 173 gas laser oscillators of this type that are already in use.
A glow discharge is performed in a low-pressure laser gas of about 0 atmospheres, and laser light is obtained by laser oscillation.

(Problem to be solved by the invention) In order to increase the output of the laser oscillator, the laser gas pressure is increased to 172
It is conceivable to raise the pressure to around 0 atm and start it up, but
If discharge is started at this level of gas pressure, the glow discharge may become uneven with respect to the electrodes, or the glow discharge may not be maintained and the discharge may shift to an arc discharge.

When the glow discharge becomes non-uniform, the intensity distribution of the obtained laser light becomes non-uniform, and when it transitions to arc discharge, laser oscillation becomes impossible.

For this reason, it is conceivable to perform an auxiliary discharge in addition to the main discharge, but this poses a problem in that it is not economical, as it requires an electrode and a power source for the auxiliary discharge.

The present invention has been made in consideration of the above points, and its purpose is to provide a method for starting a gas laser oscillator that is simple in structure, economical, and capable of reliably producing glow discharge.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve this object, according to the present invention, discharge is performed at about 1730 pressure before the laser gas pressure reaches the operating gas pressure, and then the gas is filled again. Make it.

(Function) In this way, discharge is started at a pressure lower than the operating gas pressure, and then additional gas is filled, so the discharge is evenly distributed over the electrodes without the need to provide an auxiliary discharge electrode or an auxiliary discharge power source, increasing the strength. It is possible to obtain uniform high quality laser light.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. The gas laser oscillator 10 is shown in FIG. 2(a), C
As shown in b), it is a normal configuration. That is, the laser gas is sent to the discharge section 12 by the blower 11, the laser gas is excited in the discharge section 12, and the resonator 13 emits laser light. The temperature of the laser gas that has passed through the discharge section 12 has increased, so it is cooled by the heat exchanger 14 and sent to the blower 11.
Go back and go around.

During laser operation, laser gas is supplied into the wind tunnel from the gas supply port 15. Exhaust system controlled by pressure sensor 16 to keep laser gas pressure constant in the wind tunnel! l! 17, the same amount of laser gas as the supplied amount is exhausted, and the laser gas in the wind tunnel is refreshed into the chamber during operation.

FIG. 3 shows a conventional activation pattern.

The inside of the wind tunnel is still evacuated to a vacuum of about 171,000 atmospheres, filled with laser gas, and discharged to generate laser oscillation.

FIG. 1 shows the activation pattern of the present invention.

First, the inside of the wind tunnel is evacuated to a vacuum of about 1/1000 atmosphere and filled with laser gas to a predetermined gas pressure of about 1/30 atmosphere. The pressure sensor 16 detects that this gas filling is completed and starts discharging.

After that, the laser gas is additionally filled to 1/20 atmosphere.

When discharge is started at about 1730 atmospheres in this way, glow discharge is uniformly distributed over the entire surface of the electrode. Even if the laser gas is additionally filled after this, the glow length of each electrode is gradually shortened uniformly and the arc is not extinguished, so that the glow is not unevenly distributed to the electrodes. Therefore, the excitation of the laser gas is uniformly performed, and the gain of laser oscillation is also spatially uniform, so that high-quality light can be obtained.

Other embodiments are shown in FIGS. 4 to 6.

In Figures 4 and 5, each component of the laser gas is filled individually.In the case of Figure 5, the final operating state and the mixing ratio are the same at the start of discharge, which is the case in Figure 1. You can get the same effect.

Figure 6 shows a system in which the discharge flow at the start of discharge is limited to a value that does not cause laser oscillation, and the current value is increased after the gas pressure reaches the operating pressure. It is safe because laser light is not emitted until immediately before operation, and it also has the effect of suppressing transition to arc discharge.

〔Effect of the invention〕

As explained above, according to the present invention, discharge starts at a low gas pressure and then the gas is refilled, making it possible to operate at high gas pressure without adding special circuit electrodes, thereby ensuring economical and reliable glow discharge. It is possible to provide a method for starting a gas laser oscillator that provides the following.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the starting pattern of the present invention, Fig. 2 is a diagram showing the configuration of the gas laser oscillator, (a) is a front view, (b)
) is a side view, Figure 3 is a diagram showing the conventional starting pattern,
FIGS. 4 to 6 are diagrams showing other embodiments. 10...Laser oscillator 11...Blower 12.
...Discharge section 13...Resonator 14...Heat exchanger 15...Gas supply port 16...Pressure sensor 17...Exhaust system representative Patent attorney Noriyoshi Chika Yudo Hirofumi Mitsumata η°S Pressure τi Figure 1/7''7 Pressure opening figure 3 Figure 4

Claims (4)

[Claims] (1) In a method of starting a gas laser oscillator, which obtains laser light by enclosing a laser gas in a wind tunnel and keeping the pressure constant, the gas is excited by discharge to generate laser light, the discharge is started at a pressure lower than the constant pressure maintained during operation. , a method for starting a gas laser oscillator characterized by additionally filling the laser gas. (2) A method for starting a gas laser oscillator according to claim 1, characterized in that the gas laser is filled in each component in order. (3) A method for starting a gas laser oscillator according to claim 1, characterized in that the laser gas is filled in order for each component, and the mixing ratio is the same at the discharge starting pressure as at the operating pressure. . (4) The method for starting a gas laser oscillator according to claim 1, characterized in that the discharge stream at the start of discharge is made smaller than a threshold value that causes laser oscillation.