JPH0465179A - Gas laser device - Google Patents

Abstract

PURPOSE:To stabilize the laser beam output at pulse output so as to equalize the processing quality, and immediately discharge the high voltage at the time of power stoppage so as to improve safety by making the discharge time constant approximately the same as the laser beam pulse output period. CONSTITUTION:When a semiconductor switch element 2 is made or broken, AC high voltage is generated on the secondary coil side of an AC step-up transformer 3, and this is rectified through a rectifying diode 4, and is made into DC constant voltage by a smoothing capacitor 5. Moreover, in the high voltage part comprising the trans coil 7 of a transformer, a rectifying diode 4, and a smoothing capacitor 5, the charge corresponding to the capacitances of trans struts 11a and 11b flows in from the diode 4 and the capacitance 5, and the high voltage between the high voltage part and the transformer vessel 9 at earth potential is maintained at both ends of the struts 11a and 11b. Moreover, during off of power output, the voltage becomes zero potential quickly in the discharge time constant approximately the same as laser beam pulse output period. Therefore, the danger of high voltage remaining vanishes, and the safety of the device increases, and also processing quality can be equalized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a gas laser device such as a carbon dioxide laser, in which the operational safety of a high-voltage power supply is particularly improved, and the quality of processing is improved by pulse output. This invention relates to a laser device.

Conventional technology An example of the configuration of a conventional gas laser device is shown in FIG.

In the figure, a gaseous laser medium is supplied by a blower 26 to a laser resonator 21 equipped with an output mirror 22 and a total reflection mirror 23 while being circulated between a supply duct 28a and an exhaust duct 28b, and is supplied to a discharge electrode 24a.

It is excited by the discharge caused by 24b and outputs laser light 34. The high voltage is, for example, a 200V commercial power supply 4o, which is boosted to a voltage of 30 to 5oKV necessary for starting discharge using a high-voltage transformer 41, and a high-voltage rectifier diode 42. smoothing capacitor 4
After rectification at step 3, the stain current and voltage were adjusted using a resistor 44 and a control vacuum tube 45. 27 is a gas cooler, and 46 is a high voltage discharge resistor. A high-voltage capacitor 43 with a large capacitance was used to boost and rectify the voltage from commercial voltage to several tens of kilovolts.

Problems to be Solved by the Invention However, in the above configuration, when the power supply device is stopped, charge remains accumulated in the smoothing capacitor 43, so the high voltage discharge resistor should not touch the metal fitting connected to the ground potential. There were many safety issues when operating gas laser equipment, such as having to discharge the gas by using a gas laser, or waiting for a long time until it self-discharges. In addition, when outputting pulses that intermittent laser light output, the voltage remaining in the smoothing capacitor 43 when the laser light is turned off fluctuates from pulse to pulse, so the voltage increases to the discharge starting voltage at the time of the next pulse output. There was a problem that the processing time varied and the width of the pulse output became inconsistent, making it impossible to obtain uniform processing quality.

The purpose of the present invention is to reduce the variation in laser beam power width during pulse output, and to immediately discharge high voltage when the power is turned off, thereby increasing the safety during operation of a gas laser device and ensuring uniform processing quality. It is to be.

Means for Solving the Problems In order to achieve the above object, in the gas laser device of the present invention, the high voltage power supply has a frequency of 10 KHz.
Connect a semiconductor switch element to a low-voltage DC power supply that can change the effective voltage as described above, connect the primary side of an AC step-up transformer to the high-strength terminal of the semiconductor switch element,
A rectifier circuit is connected to the secondary side of an AC step-up transformer, and a high-voltage capacitor is connected to the rectifier circuit. The discharge time constant due to the capacitance and resistance between the AC step-up transformer, rectifier circuit, high-voltage capacitor, and the metal container is approximately the same as the optical pulse output period. This is what I did.

Effects According to the present invention, the AC step-up transformer, the rectifier circuit, and the high-voltage capacitor are made small due to the above-described configuration, so that they can be stored together in a metal container, and a high-voltage discharge resistor is not required.

Furthermore, the discharge time constant due to the capacitance and resistance between the AC step-up transformer, rectifier circuit, high-voltage capacitor, and metal container is made almost the same as the laser light pulse output cycle, so the discharge of charge during the pulse output on time remains low. This means that the discharge start time for the next pulse output can be made constant.

EXAMPLES Hereinafter, examples of the present invention will be explained with reference to the drawings. FIG. 1 shows the configuration of a high voltage power supply according to an embodiment of the present invention, and FIG. 2 shows the configuration of a gas laser device according to the present invention.

In FIG. 2, the laser resonator 21 is connected to the supply duct 28a.
It is connected to the blower 26 and the gaff cooler 27 by an exhaust duct l-28b. The laser resonator 21 has a discharge 2
Discharge electrode 24a that causes 5.

2, ab, and output mirrors 2 at both ends of the laser resonator 21.
2 and a total reflection mirror 23 are attached to generate a laser beam 34. The output of the low-voltage DC power supply 1 is connected to the primary side of a step-up transformer 30, which has a primary coil and a secondary coil insulated, through a full-bridge connected semiconductor switch element 2.
A rectifying element 4 is connected to the next side, and the output of the rectifying element 4 is connected to discharge electrodes 24a and 24b via a smoothing capacitor 5. In FIG. 1, a step-up transformer 3 has a transformer coil 7 in which primary and secondary coils are coaxially wound around a ferrite core iron core 6, and the core is placed in a metal container 9 filled with insulating oil 8 with its legs vertically. The transformer is sandwiched between retainers 10a and 10b and fixed to a transformer top plate 12 attached to transformer supports 11a and 11b extending from the side wall of the metal container 9.

A rectifying element 4 and a smoothing capacitor 5 are attached and connected to the back surface of the support plate 12 that supports the ferrite core 6. The primary input of the transformer coil 7 is drawn in through a primary power connection terminal 14 attached to the transformer top plate 13, and the high voltage output is output from the smoothing capacitor 5 through the high voltage ceramic insulator 15.

In this embodiment, the capacitance C, which is a parameter of the discharge time constant τ, is the AC boost trunk 3. Rectifying element 4. Smoothing capacitor 5. Core holder 10a.

1ob, transformer struts 11a, 11b,)) is proportional to the effective opposing area between the storage parts of the lance support plate 12 and the metal container 9 and the dielectric constant ε of the insulating oil filled, and the effective distance between the storage parts and the metal container 9. is inversely proportional to.

On the other hand, the resistance R is proportional to the effective distance between the storage part and the metal container 9 and the specific resistance ρ of the insulating oil.
It is inversely proportional to the effective facing area.

Therefore, τ=CxR=ε・ρ, which is determined by the material constant of the insulating oil.

Therefore, in this embodiment, the storage parts and the metal container 9 are fixed,
Material of transformer support columns 11a and 11b.

By changing the configuration and changing the apparent appearance of the insulating oil and ρ, we constructed a high voltage power supply with the desired discharge time constant.

In this embodiment, the core holders 10a, 10b and the transformer holding plate 12 have a specific resistance of 1010 to 1011Ω.
-1 porcelain was used, and polyethylene, polypropylene, etc. with a specific resistance of 100-1 was used for the transformer pillars 11a and 11b.

Next, the operation of the embodiment of the present invention will be explained. When the semiconductor switch element 2 is turned on and off, an AC high voltage is generated on the secondary coil side of the AC step-up transformer 3. The output of the secondary coil is rectified by a rectifier diode 4 and made into a constant DC voltage by a smoothing capacitor 5. Transformer coil 7 of AC step-up transformer 3
and rectifier diode 4. In the high voltage section consisting of the smoothing capacitor 5, charges corresponding to the capacitance of the transformer columns 11a and 11b flow from the diode 4 and the capacitor 5, and the high voltage section and the transformer container 9 at ground potential are connected at both ends of the transformer columns 11a and 11b. Maintain high voltage between.

Furthermore, while the power output is off, the voltage quickly becomes zero potential with a discharge time constant that is approximately the same as the laser light pulse output cycle. This eliminates the risk of high voltage remaining and increases the safety of the gas laser device. Further, residual charges are released during the pulse output off period, and the voltages applied to the discharge electrodes 24a and 24b are made equal for each pulse, so that the discharge current-voltage characteristics during pulse output are stabilized. As a result, the laser light output becomes the same pulse output train, and the processing quality becomes uniform.

Effects of the Invention As described above, according to the gas laser device of the present invention, the laser light output during pulse output can be stabilized to improve processing quality, and at the same time, high voltage can be immediately discharged when the power supply is stopped. This increases safety.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a high voltage power supply according to an embodiment of the present invention;
The figure is a block diagram of a gas laser device of the present invention, and FIG. 3 is a block diagram of a conventional gas laser device. 1...Low voltage DC power supply, 2...Semiconductor switch element, 3...AC step-up transformer, 4...
... Rectifier circuit, 5 ... High voltage capacitor,
8...Insulating oil, 9...Metal container, 10
a, 1 ob, 1 l b, 14---
- Holding member, 21... Laser resonator, 24a, 2
4b...discharge electrode, 26...discharge, 2
6...Blower, 2... Gas cooler (
cooler), 28a, 28b...supply duct and exhaust duct (air guide section), 34...laser light. Name of agent Patent attorney Shigetaka Awano and one other person Take a look at the sb-family!Tar 11t IC--Iniwa O(

Claims (1)

[Claims] An excitation unit that discharge-excites a gas laser medium, a high-voltage power supply that generates discharge, a laser resonator that excites the gas laser medium and extracts laser light, and a blower that blows air through the gas laser medium. In a gas laser device equipped with a cooler for the gas laser medium and an air guiding section that guides the gas laser medium from a blower to the laser resonator, a semiconductor is used as a low voltage DC power supply that can change the effective voltage at a frequency of 10 KHz or more. Connect the switch element,
The primary side of an AC step-up transformer is connected to the output terminal of the semiconductor switch element, a rectifier circuit is connected to the secondary side of the AC step-up transformer, and a high-voltage capacitor is connected to the rectifier circuit to form a high-voltage power supply. The AC step-up transformer, the rectifier circuit, and the high-voltage capacitor are fixed on a holding member provided in a metal container filled with insulating oil and set to a ground potential, and the AC step-up transformer described above,
A gas laser device characterized in that a discharge constant due to capacitance and resistance between a rectifier circuit, a high-voltage capacitor, and the metal container is made almost the same as a laser light pulse output period.