JPS60157281A - Gas laser oscillation device - Google Patents

Abstract

PURPOSE:To enable the power of laser beams stable even with pulse widths of 0.1ms or less to be obtained by a method wherein one end of a resistor is connected in series to one of the electrodes of a discharge tube, and a capacitor is connected between the other electrode and the other end of the resistor. CONSTITUTION:When a transistor 3 is turned OFF, the difference of potential between a plate voltage and an impressed voltage caused by a high-withstand voltage vacuum tube 2 is given across both ends of the capacitor 6, leading to charge for the difference of potential. Next, when the transistor 3 turns on, the plate voltage of the vacuum tube 2 falls by several kV, and discharge currents flow; at the same time the charging of the capacitor 6 is furthered. When the vacuum tube 2 turns OFF, most of the discharge currents are cut OFF. At this time, the energy accumulated in the capacitor 6 flows in the form of micro current through a closed circuit made up of the anode side electrode 1a of the discharge tube 1, its cathode side electrode 1b, the resistor 5, and the capacitor 6. Since the laser medium can be kept into the state of ionization during the pulse OFF time by this micro current, a next pulse oscillation can be smoothly performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a gas laser oscillation device that excites a laser medium by discharge and generates continuous pulse oscillation.

Conventional configuration and problems thereof In recent years, in laser processing, processing using continuous pulse oscillation laser output has become mainstream. Furthermore, in order to shorten the processing time, a conventional example in which the laser pulse power with a significant laser peak power is 8 or less will be explained with reference to FIGS. 1 and 2 of the drawings.

FIG. 1 shows part of a discharge current control circuit of a conventional gas laser oscillation device. In Fig. 1, 1 is a discharge tube, 1a is an L pole on the anode side, 1b is an electrode on the cathode side, 2 is a high-voltage vacuum tube, 3 is a transistor, 4 is a resistor for current limiting. It is wired as follows.

Figure 2 shows the discharge current waveform and laser beam power waveform when continuous pulse oscillation is performed by the discharge current control circuit in Figure 1. 3. Next is the operation of conventional continuous pulse oscillation. About rjj), I will explain.

The discharge current flowing between the anode side electrode 1a and the cathode side electrode 1b is controlled by controlling the bias voltage across the horn of the high pressure vacuum 11g2 by turning the transistor 30 on and off. By applying an on/off pulse signal to the base of the transistor 3, however, in the above configuration, when the on/off time of the pulse becomes 0.1 mS or less, as shown in FIG. As shown in the figure, the discharge delay affects the waveform of the discharge current and the waveform of the laser beam power P, making it impossible to perform continuous pulse oscillation properly. Second
In the figure, the broken line is the base signal waveform of the transistor 3.

Therefore, it was found that the instability of this discharge affected the laser beam power during continuous pulse oscillation, and had an adverse effect on high-speed machining.

Therefore, 0. It has been desired to develop a gas laser oscillation device that can obtain stable laser beam power even with pulses of I InS or less.

Purpose of the Invention In view of the above drawbacks, it is an object of the present invention to provide a gas laser oscillation device that can obtain stable laser beam power even with a pulse width of 0.1 mS or less. In order to achieve this, the gas laser oscillation device of the present invention excites a laser medium by discharge and performs continuous pulse oscillation, in which one end of a resistor is connected in series with one of the electrodes of the discharge tube, and the other end is connected in series with one end of the electrode of the discharge tube. A capacitor is connected between the electrode and the other end of the resistor.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 and 4 of the drawings.

FIG. 3 shows a part of the discharge current control circuit of the Cas laser oscillation device in one embodiment of the present invention. 1.1a
, 1b12.3.4 is the same discharge tube, anode side electrode, cathode side electrode, high voltage vacuum tube, transistor,
This is a current limiting resistor. Further, 5 is a resistor connected between the cathode side electrode 1b of the discharge tube 1 and the plate of the vacuum tube 2, and 6 is connected between the end of the resistor 5 on the opposite side from the cathode side electrode 1b and the anode side electrode 1a. It is a capacitor that has been

The operation of the circuit shown in FIG. 3 will be explained below.

When the transistor 3 is off, a potential difference between the plate voltage of the high voltage vacuum tube 2 and the applied voltage is applied to both ends of the capacitor 6, and the capacitor 6 is charged by the potential difference.

Next, when the transistor 3 is turned on, the plate voltage of the high voltage vacuum tube 2 drops by several kV, and a discharge current begins to flow. At that time, charging of the capacitor 6 is further progressed at the same time. When the high voltage vacuum tube 2 is turned off, most of the discharge current is cut off. However, at this time, the energy stored in the capacitor 6 flows as a minute current in a closed circuit formed by the anode side electrode 1 of the discharge tube 1, the cathode side electrode 1b, the resistor 5, and the capacitor 6. The amount of minute current flowing at this time and the time it continues to flow depend on the resistance value of the resistor 6 and the capacitance value of the capacitor 6. That is, the laser medium can be kept in an ionized state during the pulse-off period by this small current, so that the next pulse oscillation can be performed smoothly.

Figure 4 shows the waveforms of the discharge current 0, beam power PO, and transistor 30 base signal during continuous pulse oscillation in Figure 3. Comparing Figure 4 and Figure 2, As can be seen, the waveform of the discharge current also flows stably with almost no distortion. It is clear that the beam power has also been increased and it has become possible to obtain a pulse output with a high peak power.

Effects of the Invention As described above, the present invention improves the increase and stability of pulse output.
In particular, it is possible to maintain pulse width even when the pulse width is 0.1 ms or less, and extremely high precision and high-speed machining are possible, resulting in excellent effects.

[Brief explanation of drawings]

FIG. 1 is a discharge current control circuit diagram of a conventional gas laser oscillation device, FIG. 2 is a characteristic diagram of the conventional example, FIG. 3 is a discharge current control circuit diagram of a gas laser oscillation device according to an embodiment of the present invention, and FIG. The figure is a characteristic diagram in the same example. 1...discharge tube, 1a, 1b...electrode, 2...
...High voltage vacuum tube, 3...Transistor, 4, 5...Resistor, 6. Capacitor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Of 02 Heat pulse time (inertia S) ----H Figure 3 a Figure 4 OL 0.2

Claims (1)

[Claims] In a gas laser oscillation device that excites a laser medium by discharge to generate continuous pulse oscillation, one end of a resistor is connected in series to one of the electrodes of the discharge tube, and a capacitor is connected between the other electrode and the other end of the resistor. gas laser oscillation device.