JPS62136086A - Oscillation control method for laser oscillator - Google Patents

Abstract

PURPOSE:To avoid the damage of a mirror and improve the stability of a laser oscillator by a method wherein, when a pulse signal waveform, which controls a pulse oscillation, is changed over from an oscillation signal mode to an oscillation interruption signal mode, a certain time constant is provided. CONSTITUTION:Under the condition of oscillation OFF, the potentials of (+) and (-) terminals are determined by a voltage dividing ratio of high resistances 8 and 8. As a vacuum tube 9 is OFF, no discharge is induced in a discharge tube 3. Under the condition of oscillation ON, the ON signal is inputted to the base of a transistor 10 and the vacuum tube 9 is ON and its (-) terminal is temporarily at the zero potential and the whole voltage of the (+) terminal is applied to the discharge tube 3 and a glow discharge is induced in the discharge tube 3. If a certain time constant is provided in the transition from ON to OFF of the pulse signal, the voltage of the (-) terminal can be reduced significantly. With this constitution, a discharge to a mirror 6 can be avoided and the damage of the mirror is avoided so that the stability and reliability of the laser oscillator can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of controlling oscillation of a laser oscillator, and an overview of a conventional laser oscillator will be explained with reference to FIG.

The laser medium gas is circulated in a circulation system 1 by a blower 2, and in a discharge tube 3 provided in a part of the circulation system 1, a DC voltage 5 is applied between electrodes 4 provided at both ends of the discharge tube 3. By applying it, a glow discharge is generated in the discharge tube 3, the laser medium gas is excited, a laser beam is generated, and the laser beam is amplified between the mirrors 6 disposed coaxially with and facing the discharge tube 3. A part of it is taken out to the outside. 7 is a heat exchanger for lowering the gas temperature.

As for the oscillation mode, oscillators with continuous oscillation and pulse oscillation are common.

Here, an example of a control circuit that controls oscillation is shown in the third section.
As shown in the figure.

Electrodes 4 are provided at both ends of the discharge tube 30, one electrode is used as one electrode, the other electrode 4 is used as an electrode, and a voltage of about 20 to 30 KV is applied to the electrodes.
A DC voltage of 5 is applied. In the oscillation OFF state, the potentials of the J-pole and one pole are determined by the voltage division ratio of the high resistance 8.8. At this time, no discharge occurs within the discharge tube 3 because the vacuum tube 9 is turned off. When the oscillation is ON, an ON signal is input to the base of the transistor 10, and the vacuum tube 9 becomes ONL.
The − pole temporarily becomes Ov, and all the voltage of the seed is applied to the discharge tube 3, and a glow discharge is generated within the discharge tube 3.

At the time of pulse oscillation, a pulse signal may be input to the transistor 1o. The relationship between the pulse signal and the voltage of one pole at that time is shown in FIG.

Problem to be Solved by the Invention When the pulse signal is ON, the voltage at the negative pole is low, but the voltage at the pulse O is low.
During the transition period when it becomes FF, the voltage increases rapidly. This means that even if the signal is turned off, the potential will instantly become almost the same as that of the offspring through the interior of the discharge tube 3. At this time, a discharge occurs from one pole to the mirror 6 shown in FIG. 2, damaging the mirror 6 and impairing the stability of the laser oscillator.

Means for Solving the Problems In order to solve the above problems, the present invention circulates a laser medium gas in a circulation system, and applies a DC voltage between electrodes at both ends of a discharge tube provided in a part of the circulation system. By doing so, a glow discharge is generated in the discharge tube, the laser medium gas in the discharge tube is excited, and a laser beam is generated.The laser beam is amplified between mirrors installed coaxially with the discharge tube and facing each other, and pulse oscillation is generated. In a laser oscillator having this function, switching from an oscillation signal of a pulse signal waveform that controls pulse oscillation to an oscillation stop signal is performed with a time constant.

Effect: The above measures prevent mirror damage and increase the stability of the laser oscillator.

Example Examples of the present invention will be described below.

The gas laser oscillator and its electric control circuit are as shown in FIGS. 2 and 3, and their explanation will be omitted.

The relationship between the pulse signal input to the transistor 10 and the unipolar voltage is as shown in FIG.

That is, by providing a certain time constant for the transition of the pulse signal from ON to OFF, the voltage at the negative pole is significantly lower than in the conventional example.

As a result, discharge to the mirror 6 is prevented.

Effects of the Invention As described above, according to the present invention, damage to the mirror can be prevented and stability and reliability as a laser oscillator can be improved.

[Brief explanation of drawings]

FIG. 1 is a waveform diagram of a pulse signal and a unipolar voltage showing a method of controlling oscillation of a laser oscillator in an embodiment of the present invention, and FIG.
3 is a schematic configuration diagram of a general laser oscillator, FIG. 3 is an electrical control circuit diagram thereof, and FIG. 4 is a waveform diagram of pulse signals and unipolar voltage showing a conventional oscillation control method of a laser oscillator. 1...Circulatory system, 3...Discharge tube, 4...
・・・・Electrode, 6°°°゛°″ζfu 0 Name of agent Patent attorney Toshio Nakao and 1 other person 1st
Figure 2 Figure 51 Photovoltage 5 Section Current Electricity 3 Kokime Tube Figure 4

Claims (1)

[Claims] By circulating the laser medium gas in the circulation system and applying a DC voltage between the electrodes at both ends of the discharge tube provided in a part of the circulation system, a glow discharge is generated in the discharge tube, and the inside of the discharge tube is heated. A laser oscillator that excites a laser medium gas to generate a laser beam, amplifies it between mirrors disposed coaxially and facing the discharge tube, and has a pulse oscillation function. A method for controlling oscillation of a laser oscillator, characterized in that switching from an oscillation signal to an oscillation stop signal is performed with a time constant.