JPS62265785A - Gas laser oscillator - Google Patents

Abstract

PURPOSE:To perform the stable laser oscillation at the optimum consumption while avoiding the wasteful consumption of medium by a method wherein an oxygen concentration detector 12 is provided in a discharge tube 1 exciting gas laser medeum which is exhausted from and supplied for the discharge tube 1 to keep the oxygen concentration within the range of reference value. CONSTITUTION:When the concentration of oxygen contained in a gas laser medium exceeds 0.3-0.4% changing from glow discharge to arc discharge, the excitation is deteriorated so markedly that it is very important to maintain the glow discharge for stable laser oscillation. A controller 13 provided with a circuit comparing detection signals with the reference value can input operation signals to a flow rate regulating valve 9 and an electromagnetic valve 11 whenever the detection signals exceed the reference value. When the oxygen concentration reaches a point (a), exhaust and supply of oxygen are stopped while reaching a point (c), the flow rate regulating valve 9 and the electromagnetic valve 11 are opened for specified time to reset the oxygen concentration to the point (a). Through these procedures, the stable laser oscillation can be performed while avoiding the wasteful consumption of excessive gas laser medium.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a gas laser emitting device, and particularly to a system for replenishing and exhausting a predetermined amount of laser gas.

(Prior art) In a relatively high-output gas laser oscillator, in order to prevent a decrease in laser output due to deterioration of the gas laser medium during laser operation, a predetermined amount of gas laser medium is replenished continuously or at fixed times. Efforts are being made to stabilize the laser output by preventing a decrease in gain. For example, T
EA (Transversely Excited A)
tomosphere pressure) Co.

Laser oscillator! In this case, the gas laser medium was consumed at a rate of about 2 L/min. The above values do not take into account any changes in gas components during laser oscillation of the gas laser medium, and were determined empirically.

This does not mean that the change in gas composition is controlled to stay within the permissible range. Therefore, in order to stabilize the laser oscillation, an excessive amount of gas laser medium is used. There was a problem.

(Problems to be Solved by the Invention) In view of the wasteful consumption of gas laser media as described above, an object of the present invention is to provide a gas laser oscillation device that can perform stable laser oscillation with optimal consumption. shall be.

[Structure of the invention]

(Means and effects for solving the problem) In a gas laser oscillation device, an oxygen concentration transmitter is installed in the discharge tube that excites the gas laser medium, and a detection signal exceeding the oxygen concentration standard value indicates that the oxygen concentration is within the standard value. The structure is such that the gas laser medium is evacuated and refilled from the discharge tube so as to achieve the following.

(Example) EMBODIMENT OF THE INVENTION Hereinafter, this invention will be explained based on drawing which shows an Example.

Before explaining the present invention, the circumstances leading to the present invention will be explained. That is, FIG. 2 shows the relationship between the oxygen concentration in the gas laser medium and the arc generation rate in a TEA Co laser oscillator. As is clear from this figure, when the oxygen concentration exceeds 0.3 to 0.4%, the arc occurrence rate increases rapidly. As is well known, in TEA Co, laser, excimer laser, etc., a gas laser medium is excited by glow discharge.

If the glow discharge turns into an arc discharge, the excitation effect becomes extremely poor, and it is important to maintain the glow discharge in order to achieve stable laser oscillation.

In view of the above, one embodiment of the present invention is constructed as shown in FIG. 41, which is an embodiment. Namely.

(1) is a discharge tube consisting of a cylindrical airtight container, with air released inside! An anode (2) and a cathode (3), which are poles, are provided facing each other, and are supplied with high-voltage DC pulses from a power source (4). (5), CG) are a total reflection mirror and an output mirror that constitute an optical resonator, and are airtightly installed on both ends of the discharge W (1) coaxially with the axis of the discharge tube (1). . (The force is the supply source that supplies the gas laser medium into the discharge tube (1), and the pressure h!1 in the supply tube (7a)
A regulator (8) and a flow rate regulating valve (9) are provided. θQ is the exhaust pipe connected to the discharge tube (1), and ′α
A solenoid valve υ is provided. The internal example of the discharge tube (1) is provided with an oxygen concentration detector (121), the detection signal of which is sent to the control device α9. Each component constitutes a gas exchange means.The control device α3 has a circuit for comparing the detection signal with a reference value, and when a signal exceeding the reference value is obtained, a flow rate regulating valve (9) is provided. ) and a solenoid valve (lυ).

Here, the specific control operation of the control device R (13) will be explained based on FIG. Measure the number of times, and (d) where the oxygen concentration is between 0.3 and 0.4%.
Predict the number of discharges until reaching the point. In this case, the increase in oxygen concentration can be approximated by an exponential relationship with the number of discharges. Note that point (C) above is 1/2 of point (d), point (b) is 1/2 of point (C), and point (a) is 1/2 of point (b). It is a point. Further, the point (d) may be set arbitrarily, but preferably around 4%. Next, time C until reaching point (d) (number of discharges at point d -
Calculate the number of discharges up to now)/number of discharge line repetitions] t. Based on this value, calculate the exhaust volume and the replenishment volume of the same 1. Exhaust f (replenishment volume) = gas capacity of the discharge tube / l C'-,
Calculate the amount using the formula and start evacuation and replenishment.

When the oxygen concentration falls below point (a), exhaust/replenishment is stopped and the flow i adjustment valve (9) and tU valve (11) are closed to perform a sealing operation until the oxygen concentration reaches point (c). . When point (C) is reached, the flow rate adjustment valve (9), solenoid valve (
11) is opened for a predetermined time and the oxygen concentration is returned to point (a). The above operations are repeated during laser firing.

〔Effect of the invention〕

Since the oxygen concentration of the gas laser medium in the discharge tube during laser oscillation is constantly detected, control is implemented to correct subtle or sudden changes in the gas laser medium. As a result, stable laser oscillation can be performed, and the reliability of the oscillation device itself can be improved due to the stability of the laser output. In addition, gas laser media have also become consumed based on quantitative detection.

It is now possible to eliminate the waste of using excessive gas laser media.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between oxygen concentration and arc generation rate, and FIG. 3 is a diagram showing the increase in oxygen concentration depending on the number of discharges. (1)...Discharge tube (4)...Power supply department representative Patent attorney Nori Chikura Kanshu Takehana Kikuo Denkomaya Figure 1

Claims (1)

[Claims] a discharge tube that excites a sealed gas laser medium at a predetermined pressure; a power supply unit that supplies electric power for discharge to the discharge tube;
a gas exchange means for exhausting a part of the gas laser medium used for laser oscillation in the discharge tube and replenishing the same amount of unused gas laser medium; an oxygen concentration detector provided in the discharge tube; It is characterized by comprising a control device which inputs a detection signal of oxygen concentration from a detector and causes the gas exchange means to operate when the detection signal is outside the range of the reference value and stop when the detection signal is within the range of the reference value. Gas laser oscillation device.