JPH04778A - Gas laser generator - Google Patents

Abstract

PURPOSE:To increase the reliability of a high-voltage high-frequency transformer and generate a stable light beam by providing a high-voltage power-supply section comprising a DC smoothing circuit, a high-frequency switching element, a high-voltage high-frequency transformer, a high-voltage rectifying circuit and a high-voltage smoothing circuit and setting the capacitance of the smoothing capacitor of the high-voltage smoothing circuit at 100 to 800 PF. CONSTITUTION:A commercial AC power supply of three-phase 200V is used for input of a high-voltage power-supply section 4. A DC voltage obtained by rectifying the three-phase 200V by a DC smoothing circuit 14 is applied to a high-frequency switching element 16 controlled by a switching control circuit 15, an intermittent DC voltage is input to a primary winding of a high-voltage high-frequency transformer 17, and a high-frequency voltage raised to a secondary winding is induced. The high-frequency voltage is applied to a high-voltage rectifying circuit 19 and rectified. The output is smoothed by a high-voltage smoothing circuit 20 in which capacitors having a capacitance value of 100 to 800 PF are used. As a result, a high DC voltage of approximately 30 kV is output.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a gas laser oscillation device, and is intended to improve the reliability of the device and stabilize the oscillation output.

(Prior art) Figure 4 shows a conventional axial flow type gas laser oscillator.
Laser gas is flowed in the optical axis direction of a discharge tube made of an insulator,
FIG. 2 is a diagram showing the configuration of a gas laser oscillation device that applies a high voltage between electrodes provided at both ends of a discharge tube to generate a laser beam inside the discharge tube.

1 is a discharge tube made of a dielectric material such as glass, 2 and 3 are electrodes arranged inside the discharge tube 1, and 4 is a high voltage power supply section connected to these electrodes 2 and 3, for example, a high voltage of 30 kV. is applied between both electrodes 2 and 3. 5 is a laser discharge space between electrodes 2 and 3, 6 is a total reflection mirror of the laser, and 7 is also a partial reflection mirror, and these total reflection @ 6
, the partial reflecting mirrors 7 are arranged opposite to each other with the laser discharge space 5 interposed therebetween to form an optical resonator.

Further, 8 represents a laser beam outputted from the above-mentioned partially reflecting fIL7, and arrow 9 is the flow direction of the laser gas, which is circulating in the laser device formed in an axial flow type. 10 is an air pipe; 11 and 12 are heat exchangers for reducing the discharge in the laser discharge space 5 and the temperature of the laser gas rising by the blower; and 13 is a blower.

Normally, for laser oscillation, air is blown in the laser discharge space 5 to obtain a gas flow of about 100 m 2 /see.

In the conventional axial flow gas laser oscillation device as described above, first, a high voltage is applied to the electrodes 2 and 3 from the high voltage power supply section 4,
A glow discharge is generated in the laser discharge space 5. The laser gas passing through the laser discharge space 5 is excited to oscillate by the discharge energy of the glow discharge, and the excited laser gas is brought into a resonant state by the optical resonator constituted by the total reflection mirror 6 and the partial reflection mirror 7. A laser beam 8 is output from the partial reflecting mirror 7, and is used for laser processing or the like.

FIG. 5 shows the configuration of the high voltage power supply section 4. Normally, a three-phase 200V commercial AC power source is applied to its input, and the DC voltage obtained by rectifying the AC input by the DC smoothing circuit 14 is applied to the switching control circuit. In addition to the high-frequency switching element 16 controlled by the high-voltage high-frequency transformer 15, the DC voltage input to the primary winding of the high-voltage high-frequency transformer 17 is intermittent, thereby increasing the voltage to the secondary winding of the high-voltage high-frequency transformer 17. A high frequency voltage is induced, and the high voltage rectifying and smoothing circuit 18 outputs a DC high voltage of approximately 30 kV.

In addition.

The switching control circuit 15 controls the high frequency switching element 16 at a frequency of 5 kHz to 50 kHz corresponding to the laser output.
It is controlled to operate at any switching frequency between l(z).

(Problems to be Solved by the Invention) The conventional gas laser oscillation device is configured as described above.
The voltage and current at the start of the gas discharge behave as shown in FIG.

In other words, in FIG. 6, the vertical axis shows voltage or current, and the horizontal axis shows time. When the inrush current at the start of discharge when the power is turned on is large, stress is applied to the high voltage high frequency transformer 17, and as the operating time elapses, There is a drawback that the high voltage high frequency transformer 17 may be damaged. In addition, the high voltage generated by the high voltage power supply unit 4 generates ripples that are twice the switching frequency of the high frequency switching element 16 and six times the frequency of the commercial AC power supply, which causes the problem that the stability of the laser beam is poor. had.

In view of the above-mentioned conventional problems, the present invention aims to provide a gas laser oscillation device that improves the reliability of the laser oscillation device and stabilizes the oscillation output.

(Means for Solving the Problems) The above object of the present invention is to provide a high voltage power supply unit for starting a trickle type gas laser oscillation device.

A high-voltage step-up means consisting of a DC smoothing circuit that converts a commercial AC power supply into DC, a high-frequency switching means that intermittents the output, a high-voltage high-frequency transformer, and a high-voltage rectifier circuit;
This is achieved by providing a high-voltage smoothing circuit for smoothing the output, and setting the capacitance of the capacitor used in the high-voltage smoothing circuit to between 100PF and 800PF.

(Function) According to the present invention, the inrush current at the start of laser discharge is limited, thereby improving the reliability of the high voltage and high frequency transformer, and making it possible to efficiently extract a stable laser beam. .

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a high voltage power supply section in one embodiment of the present invention, and since the laser oscillation section has the same configuration as that shown in FIG. 4, detailed explanation will be omitted.

In FIG. 1, the same reference numerals as in FIG. 5 indicate the same or the same functions. That is, a three-phase 200V commercial AC power source is normally used as an input to the high voltage power supply unit 4, and the switching operation of the DC voltage obtained by rectifying the AC input by the DC smoothing circuit 14 is controlled by the switching control circuit 15. In addition to the high frequency switching element 16, an intermittent DC voltage is input to the primary winding of the high voltage high frequency transformer 17, thereby inducing a boosted high frequency voltage in the secondary winding. The switching control circuit 15 controls the high frequency switching element 16 to operate at an arbitrary switching frequency between 5 kHz and 50 kHz corresponding to the laser output.

Reference numeral 19 denotes a high voltage rectifier circuit, which is a feature of the present invention, which applies and rectifies the high frequency voltage induced in the secondary winding of the high voltage high frequency transformer 17, and its output is smoothed by the high voltage smoothing circuit 20. Ru.

The high voltage smoothing circuit 20 uses a capacitor having a capacitance value of 100PF to 800PF as a smoothing capacitance, thereby outputting a DC high voltage of about 30kV.

Figure 2 shows the inrush current at the start of discharge (vertical axis) and the capacitor capacity (horizontal axis) when the gas laser oscillator shown in Figure 4 is started by the high voltage power supply unit 4 shown in Figure 1. be. As is clear from the figure, it was observed that the rush current increases in proportion to the capacitance of the capacitor, and when the inrush current exceeds 800PF, the laser discharge shifts to an arc discharge.

Figure 3 shows the capacitor capacity of the high voltage smoothing circuit 20 (horizontal axis), the laser beam capacity (horizontal axis), and the vibration rate of the laser beam (vertical axis) with the switching frequency constant (= 1/2 x high voltage ripple frequency). This figure shows that the stability of the laser beam hardly changes when the capacitance of the capacitor exceeds 100 PF.

As can be understood from the above-mentioned embodiments, the present invention provides a high-voltage power supply configured by a trickle-type gas laser oscillation device, a DC smoothing circuit, a high-frequency switching element, a high-voltage high-frequency transformer, a high-voltage rectifier circuit, and a high-voltage smoothing circuit. By setting the capacitor capacity of the high voltage smoothing circuit to between 100PF and 800PF, the reliability of the high voltage high frequency transformer is improved and it is a laser beam oscillation device that generates a stable laser beam. be.

(Effects of the Invention) As is clear from the above description, the present invention provides a high voltage power supply section of a gas laser oscillation device using a DC smoothing circuit, a high frequency switching element, a high voltage high frequency transformer, a high voltage rectifier circuit, and a high voltage smoothing circuit. Since the smoothing capacitor capacity of the high voltage smoothing circuit is set between 100PF and 800PF, the reliability of the high voltage high frequency transformer is improved and a stable laser beam can be generated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a high voltage power supply section, which is the main part of an embodiment of the present invention, FIGS. 2 and 3 are characteristic diagrams to assist in explanation, and FIG. FIG. 5 is a block diagram of a high voltage power supply unit that starts the gas laser oscillation device of FIG. 4, and FIG. 6 is a diagram showing the behavior of voltage and current at the start of gas discharge. DESCRIPTION OF SYMBOLS 1... Discharge tube, 2, 3... Electrode, 4... High voltage power supply section, 5... Laser discharge space, 6... Total reflection mirror, 7... Partial reflection mirror, 8.・Laser beam,
10... Air pipe, 11° 12... Heat exchanger, 13
...Blower, 14...DC smoothing circuit, 15...
-Switching control circuit, 16... switching element, 17... high voltage high frequency transformer, 18...
High voltage rectifier smoothing circuit, 19... High voltage rectifier circuit, 2
0...High voltage smoothing circuit. Patent applicant: Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] In an axial flow type gas laser oscillator, the high voltage power supply unit that starts it includes a DC smoothing circuit that converts a commercial AC power supply to DC, a high frequency switching means that cuts and cuts the output, a high voltage high frequency transformer, and a high voltage rectifier circuit. 1. A gas laser oscillation device comprising: a high-voltage step-up means; and a high-voltage smoothing circuit for smoothing the output thereof, and a capacitor capacity used in the high-voltage smoothing circuit is between 100PF and 800PF.