JP2830404B2 - Gas laser device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device, such as a carbon dioxide laser, which improves the safety in operation of a high-voltage power supply and the quality of processing by pulse output. The present invention relates to a laser device.

2. Description of the Related Art FIG. 3 shows a configuration example of a conventional gas laser device. In the figure, a gas laser medium is supplied from a blower 26 to a laser resonator 21 on which an output mirror 22 and a total reflection mirror 23 are attached, and a supply duct 28a.
The laser beam 34 is circulated and supplied between the exhaust duct 28b and is excited by the discharge by the discharge electrodes 24a and 24b to output a laser beam 34. For high voltage, for example, a 200V commercial power supply 40
At 41, the voltage was raised to a voltage of 30 to 50 KV necessary for starting discharge, rectified by a high-voltage rectifier diode 42 and a smoothing capacitor 43, and then the current and voltage were adjusted by a resistor 44 and a control vacuum tube 45. 27 is a gas cooler, 46 is a high-pressure discharge resistor. In order to rectify the boost from commercial voltage to several tens of KV, a high-voltage capacitor 43 having a large capacitance has been used.

However, in the above-described configuration, when the power supply device is stopped, the charge remains stored in the smoothing capacitor 43, so that the metal fitting that connects the high-voltage discharge resistor to the ground potential is contacted. There are many problems in the safety of the gas laser device operation, such as causing discharge and waiting for a long time until natural discharge. Also, at the time of pulse output for cutting off the laser light output, the voltage remaining in the smoothing capacitor 43 fluctuates for each pulse when the laser light is turned off, so that the voltage is raised to the discharge start voltage at the time of the next pulse output. However, there is a problem in that the width of the pulse output is not uniform due to the variation in the time required, and uniform processing quality cannot be obtained.

An object of the present invention is to reduce the variation of the laser beam output width at the time of pulse output, and to discharge the high voltage immediately when the power supply is stopped to increase the safety during operation of the gas laser device and to make the processing quality uniform. That is.

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 is changed to a low-voltage DC power supply that can change the effective voltage at a frequency of 10 KHz or more. A switch element is connected, a primary side of an AC boost transformer is connected to an output terminal of the semiconductor switch element, a rectifier circuit is connected to a secondary side of the AC boost transformer, and a high-voltage capacitor is connected to the rectifier circuit. The AC boost 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. The discharge time constant due to the capacitance and resistance between the metal containers is substantially the same as the laser light pulse output cycle.

Operation The present invention has the above-described configuration, and provides an AC step-up transformer,
Since the rectifier circuit and the high-voltage capacitor are compact, they can be stored together in a metal container, eliminating the need for a high-voltage discharge resistor.

Furthermore, since the discharge time constant due to the capacitance and resistance between the AC boost transformer, rectifier circuit, high-voltage capacitor and metal container is almost the same as the laser light pulse output cycle, the charge discharge during the pulse output ON time is kept low. The discharge start time at the time of the next pulse output can be made constant.

Embodiments Hereinafter, embodiments of the present invention will be described 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 of the present invention. In FIG.
The laser resonator 21 is connected to a blower 26 and a gas cooler 27 by a supply duct 28a and an exhaust duct 28b. The laser resonator 21 has discharge electrodes 24a and 24b that cause a discharge 25,
An output mirror 22 and a total reflection mirror 23 are attached to both ends of the laser resonator 21 to generate a laser beam 34. The output of the low-voltage DC power supply 1 is connected to a primary side of a step-up transformer 3 having a primary coil and a secondary coil insulated through a full-bridge-connected semiconductor switch element 2, and a rectifying element is provided on the secondary side. The output of the rectifying element 4 is connected to the discharge electrodes 24a and 24b via the smoothing capacitor 5. In FIG. 1, a step-up transformer 3 has a transformer coil 7 in which a primary / secondary coil is coaxially wound around a ferrite core iron core 6, and an insulating oil 8
Core jig with the legs in a metal container 9 filled with
The transformer holding plate 12 attached to the transformer columns 11a and 11b protruding from the side wall of the metal container 9 and sandwiched by 10a and 10b.
It is fixed to. Support plate indicating ferrite core 6
A rectifying element 4 and a smoothing capacitor 5 are attached and connected to the back surface of the device 12. The primary input of the transformer coil 7 is drawn from a primary input 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 the present embodiment, the capacitance C, which is a parameter of the discharge time constant τ, is the value of the AC step-up transformer 3, the rectifying element 4, the smoothing capacitor 5, the core holders 10a, 10b, the transformer posts 11a, 11b, and the transformer support plate 12. It is proportional to the effective facing area between the storage component and the metal container 9 and the dielectric constant ε of the filled insulating oil, and is inversely proportional to the effective distance between the storage component and the metal container 9.

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

Therefore, τ = C × R = ε · ρ, which is determined by the material constant of the insulating oil.

Therefore, in this embodiment, the high voltage power supply having the desired discharge time constant is obtained by changing the apparent ε and ρ of the insulating oil by changing the material and the configuration of the transformer columns 11a and 11b while keeping the storage component and the metal container 9 constant. Configured.

Core drop holder 10a in the present embodiment, 10b and using the specific resistance of ¹⁰ 10 ~10 ¹¹ Ω-cm porcelain trans holding plate 12, polyethylene trans posts 11a, the resistance ratio in 11b is 10 ¹⁴ Ω-cm , Polypropylene or the like.

Next, the operation of the embodiment of the present invention will be described. 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 the rectifier diode 4 and converted to a constant DC voltage by the smoothing capacitor 5. In the high-voltage section composed of the transformer coil 7 of the AC step-up transformer 3, the rectifier diode 4, and the smoothing capacitor 5, an electric charge corresponding to the capacitance of the transformer columns 11 a, 11 b flows from the diode 4 and the capacitor 5 and both ends of the transformer columns 11 a, 11 b. To maintain a high voltage between the high voltage portion and the transformer container 9 at the ground potential. Further, while the peripheral power of the power supply is off, the voltage quickly becomes zero potential with a discharge time constant substantially equal to the laser light pulse output cycle. For this reason, there is no possibility that a high voltage remains, and the safety of the gas laser device is improved. In addition, the residual charges are released during the pulse output off period, and the voltage applied to the discharge electrodes 24a and 24b is adjusted for each pulse, so that the discharge current-voltage characteristics at the time of pulse output are stabilized. As a result, the laser light output becomes the same pulse output train, and the processing quality becomes uniform.

Effect of the Invention As described above, according to the gas laser device of the present invention, it is possible to improve the processing quality by stabilizing the laser light output at the time of pulse output, and at the same time, immediately discharge the high voltage when the power supply is stopped. Because it can be done, safety is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a high-voltage power supply according to an embodiment of the present invention, and FIG.
FIG. 1 is a configuration diagram of a gas laser device of the present invention, and FIG. 3 is a configuration 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, 10a, 10b, 1
1b, 14 ... holding member, 21 ... laser resonator, 24a, 24b ...
Discharge electrode, 25 discharge, 26 blower, 27 gas cooler (cooler), 28a, 28b supply duct and exhaust duct (wind guide), 34 laser light.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor ▲ Yoshi ▼ Shuzo Sumi 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Within Sangyo Co., Ltd. (72) Inventor Shigeki Yamane 1006 Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. References JP-A-62-190883 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S 3/097-3/0977

Claims (1)

(57) [Claims] An exciting unit for exciting a gas laser medium by discharge;
A high-voltage power supply that generates electric discharge, a laser resonator that excites the gas laser medium to extract laser light, a blower that blows the gas laser medium, and a cooler for the gas laser medium,
In a gas laser device equipped with a baffle for guiding a gas laser medium from a blower to a laser resonator, a semiconductor switch element is connected to a low-voltage DC power supply capable of changing an effective voltage at a frequency of 10 KHz or more, and the semiconductor switch is provided. Connect the primary side of the AC step-up transformer to the output terminal of the element, connect a rectifier circuit to the secondary side of the AC step-up transformer, and connect a high-voltage capacitor to the rectifier circuit to form a high-voltage power supply. A transformer, a rectifier circuit, and a high-voltage capacitor are fixed on a holding member provided in a metal container filled with insulating oil and set to a ground potential.
A gas laser device, wherein a discharge constant due to a capacitance and a resistance between a rectifier circuit and a voltage capacitor and the metal container is made substantially the same as a laser light pulse output cycle.