CN111200354A

CN111200354A - Power supply device for laser device

Info

Publication number: CN111200354A
Application number: CN201910987814.1A
Authority: CN
Inventors: 山口英正
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2018-11-19
Filing date: 2019-10-17
Publication date: 2020-05-26
Also published as: JP2020088031A; TW202027390A; TWI733215B; KR20200058283A

Abstract

The invention provides a laser device with improved reliability. A high-frequency power supply (400) applies a high-frequency voltage (V) to a resonance circuit (210) including a capacitance of a pair of discharge electrodes (202, 204)_RF). The overvoltage suppression circuit (500) suppresses an overvoltage between both ends of the resonance circuit (210). When the abnormality detector (600) detects an abnormality, the high-frequency voltage (V) from the high-frequency power supply (400) is stopped_RF) Application of (1).

Description

Power supply device for laser device

The present application claims priority based on japanese patent application No. 2018-216527, applied for 11/19/2018. The entire contents of this Japanese application are incorporated by reference into this specification.

Technical Field

The present invention relates to a power supply device.

Background

As an industrial processing tool, a laser processing apparatus is widely used. Laser processing apparatus using CO₂High-power gas lasers such as lasers. Fig. 1 is a block diagram of a laser apparatus 100R. The laser device 100R includes a laser cavity 200 and a power supply device 250R. The laser resonator 200 includes a pair of

discharge electrodes

202 and 204, a total reflection mirror 206, and a partial reflection mirror 208.

A pair of

discharge electrodes

202, 204 are provided to be filled with CO₂Gas chamber of iso-laser medium gasAnd (4) the following steps. An electrostatic capacitance C exists between the pair of

discharge electrodes

202, 204. The electrostatic capacitance C and the inductor L (inductor element or parasitic inductance) form a resonant frequency f_RESThe resonant circuit 210.

The power supply device 250R applies the high-frequency voltage V to the resonant circuit 210_RF. High frequency voltage V_RFFrequency f of_RF(hereinafter, referred to as synchronous frequency) is set at the frequency f of the resonant circuit_RESIs detected. By applying a high-frequency voltage V_RFA discharge current flows between the pair of

discharge electrodes

202 and 204. The laser medium gas is excited by the discharge current to form population inversion. The stimulated emission light travels back and forth within the optical resonator formed by the total reflector 206 and the partial reflector 208 and passes through the lasing medium gas to be amplified. A portion of the amplified light is output from the half-mirror 208.

The power supply device 250R includes: a DC power supply 300 for generating a stable DC voltage V_DC(ii) a And a high frequency power supply 400 for supplying a DC voltage V_DCConverted into a high-frequency voltage V_RF。

Patent document 1: japanese patent laid-open publication No. 2018-39032

Patent document 2: japanese patent laid-open publication No. 2015-32746

The present inventors have studied the laser device 100R of fig. 1 and found the following problems.

If a contact failure or the like occurs in the

discharge electrode

202 or 204, the operation may be performed in an open state. In the open state, the capacitance C becomes very small, and thus the resonance frequency of the resonance circuit becomes a very high value f_RES'. If the synchronous frequency f is continuously applied in this state₀(f₀＜f_RES') high-frequency voltage V_RFThen at the resonant frequency f_RESIn which a voltage V exceeding a high frequency is generated_RFVery high voltage of amplitude of (a). If the high voltage is applied to a semiconductor element (i.e., a power transistor) inside the high frequency power supply 400, reliability thereof is lowered.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an exemplary object of one embodiment thereof is to provide a laser device with improved reliability.

One embodiment of the present invention relates to a power supply apparatus for driving a laser resonator including a pair of discharge electrodes. The power supply device includes: a high-frequency power supply that applies a high-frequency voltage to a resonance circuit including a capacitance of the pair of discharge electrodes; an overvoltage suppressing circuit which suppresses an overvoltage between both ends of the resonance circuit or an internal node of the high-frequency power supply; a switch connected in series with the overvoltage suppression circuit: and an abnormality detector for turning on the switch when abnormality is detected.

The "abnormality" referred to herein is an abnormality that may generate an overvoltage in the power supply device. By providing the overvoltage suppressing circuit, when the resonance frequency of the resonance circuit greatly deviates from the design value, the overvoltage can be suppressed, and the semiconductor element included in the high-frequency power supply or the like can be protected. In a situation where no overvoltage is generated, by turning off the switch, it is possible to prevent a leakage current from flowing through the overvoltage suppression circuit, and to suppress noise (purgerarrester) due to the leakage current.

The housing of the laser resonator may be grounded via a ground line. The abnormality detector may detect an abnormality from a current flowing through the ground line.

The housing of the laser resonator may be grounded via a ground line, and the abnormality detector may detect an abnormality based on a potential of the housing.

The power supply device may further include: when the abnormality detector detects an abnormality, the abnormality detector notifies an external notification mechanism.

The high frequency power supply may include an inverter and a transformer having a 1-time winding connected to an output of the inverter and a 2-time winding connected to the laser resonator. The overvoltage suppression circuit may also be connected to the 1 st winding of the transformer.

The overvoltage suppression circuit may also include at least one of a voltage suppressor, a Surge protector (surgeprotective device), and a gas arrester (Surge arrester).

The overvoltage suppression circuit may also include a plurality of elements connected in series with one another. When the capacitance of each element is large, the capacitance of the overvoltage suppressing circuit can be reduced by connecting these elements in series.

The overvoltage suppressing circuit may include a capacitor having a capacitance equal to or smaller than 1/10 of the capacitance of the pair of discharge electrodes. At this time, since the capacitor serves as a load, the resonant frequency can be prevented from becoming excessively high, and overvoltage can be suppressed.

The overvoltage suppression circuit may also include an LCR load. In this case, even if the discharge electrode is opened due to an abnormality, the LCR load prevents the resonant frequency from becoming too high, and the overvoltage can be suppressed.

In addition, any combination of the above-described constituent elements or mutual replacement of the constituent elements or expressions of the present invention among methods, apparatuses, systems and the like is also effective as an embodiment of the present invention.

According to one embodiment of the present invention, the reliability of the laser device can be improved.

Drawings

Fig. 1 is a block diagram of a laser apparatus.

Fig. 2 is a block diagram of a laser device according to an embodiment.

Fig. 3 is a circuit diagram showing a configuration example of the abnormality detector.

Fig. 4 is a circuit diagram showing a configuration example of the overvoltage suppressing circuit.

Fig. 5 is a circuit diagram showing a specific configuration example of the power supply device.

Fig. 6 is a diagram showing a laser processing apparatus including a laser device.

Fig. 7 is a diagram showing a modification of the arrangement of the overvoltage suppressing circuit.

In the figure: 100-laser device, 200-laser resonator, 202, 204-discharge electrode, 206-holophote, 208-half-transparent reflector, 210-resonant circuit, 250-power supply device, 300-direct current power supply, 302-capacitor bank, 304-charging circuit, 400-high frequency power supply, 402-H bridge circuit, 404-step-up transformer, 500-overvoltage suppression circuit, 502-gas arrester (Gasarrester), 504-piezoresistor (Var resistor), 600-anomaly detector, 610-notification mechanism.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or equivalent constituent elements, components, and processes are denoted by the same reference numerals, and overlapping description thereof will be omitted as appropriate. The embodiments are merely illustrative and do not limit the invention, and all the features and combinations described in the embodiments are not necessarily essential to the invention.

Fig. 2 is a block diagram of the laser device 100 according to the embodiment. The laser device 100 includes a laser cavity 200 and a power supply device 250.

In fig. 2, the laser resonator 200 is shown as an equivalent circuit. Between the pair of

discharge electrodes

202 and 204, an electrostatic capacitance C and a resistance component R are included. The electrostatic capacitance C forms a resonant circuit 210 together with the inductor L. The resonant frequency of the resonant circuit 210 is set to f_RES. The inductor L includes at least one of parasitic inductances of the inductor components and the wiring or the substrate.

The power supply device 250 applies a high-frequency voltage V to the resonant circuit 210_RF. High frequency voltage V_RFFrequency f of_RF(hereinafter, referred to as synchronous frequency) is set at the frequency f of the resonant circuit_RESIs detected. By applying a high-frequency voltage V_RFA discharge current flows between the pair of

discharge electrodes

202 and 204. The laser medium gas is excited by the discharge current to form population inversion.

The power supply device 250 includes a dc power supply 300, a high-frequency power supply 400, an overvoltage suppression circuit 500, a switch SW1, an abnormality detector 600, and a notification mechanism 610. An output terminal of the DC power supply 300 is connected to a pair of DC buses 310, and a DC voltage V (also referred to as a DC bus voltage) stabilized at a predetermined voltage level is generated on the DC buses 310_DC。

The input of the high frequency power supply 400 is connected to the DC bus 310 to receive the DC bus voltage V_DC. The high frequency power source 400 generates a voltage having a resonant frequency f_RESIdentical frequencies (synchronous frequencies) f_RFHigh frequency voltage V of_RFAnd supplies it to the laser resonator 200. The structure of the high frequency power supply 400 is not limited, but it may include applying a direct current voltage V_DCConversion to alternating currentPressure V_ACH-bridge circuit (inverter) 402 and a method of controlling an output voltage V of the H-bridge circuit 402_ACA step-up transformer 404 for boosting.

The overvoltage suppressing circuit 500 is configured to suppress an overvoltage between both ends of the resonant circuit 210 or an internal node of the high-frequency power supply. In fig. 2, the overvoltage suppressing circuit 500 is connected to a connection node between the H-bridge circuit 402 and the step-up transformer 404, and can suppress an overvoltage of the voltage on the 1 st side of the step-up transformer 404.

To cut off the current path of the overvoltage suppression circuit 500, a switch SW1 is connected in series to the overvoltage suppression circuit 500.

When the abnormality detector 600 detects an abnormality of the laser device 100, the abnormality detection signal S is generated_ABNActive (assert) turns on switch SW 1. The "abnormality" referred to herein is an abnormality that may cause an overvoltage in the power supply device 250, in other words, an abnormality that shifts the resonance frequency to a value higher than the design value, and examples thereof include a contact failure of the

discharge electrodes

202 and 204, a drop of the inductor L, a drop of a wire connecting these, a disconnection (disconnection) of the wire, or an increase in impedance due to deterioration. In addition, the power supply device 250 may make the abnormality detection signal S after the abnormality is generated_ABNIt is effective that the abnormality detection signal S is caused to appear at a stage of the abnormality indication_ABNIs effective.

The notification mechanism 610 notifies the outside of the abnormality detection by the abnormality detector 600. For example, the notification means 610 may be a buzzer, a lamp, a display, or the like for directly notifying the user.

Alternatively, the notification unit 610 may be an interface (interface) connected to a system-side controller that controls a buzzer, a lamp, and a display. At this time, the notification mechanism 610 may indirectly notify the user of the generation of the abnormality. In this case, the controller on the system side can perform appropriate protection processing at an appropriate timing by using the notification of the occurrence of the abnormality as a trigger signal.

The above is the basic structure of the power supply device 250. The operation will be described next.

If the laser device 100 generates an abnormality (or a pre-set thereof)Mega), the abnormality detector 600 makes the abnormality detection signal S_ABNActive, turns on switch SW 1. Thereby, the overvoltage suppressing circuit 500 is connected to the high-frequency power supply 400, and the overvoltage between the nodes to which the overvoltage suppressing circuit 500 is connected is suppressed.

On the other hand, in a state where the laser apparatus 100 is normal, the abnormality detector 600 generates the abnormality detection signal S_ABNInactive (negate), opens switch SW 1. Therefore, the overvoltage suppressing circuit 500 is disconnected from the high-frequency power supply 400.

This operation of the power supply device 250 is described above. According to the power supply device 250, the overvoltage suppressing circuit 500 is provided, so that the resonant frequency f of the resonant circuit 210 is set_RESIf the voltage greatly deviates from the design value, the overvoltage can be suppressed, and the semiconductor element included in the high-frequency power supply 400 or the like can be protected. In a situation where no overvoltage is generated, by turning off the switch SW1, it is possible to prevent a leakage current from flowing through the overvoltage suppression circuit 500, and to suppress noise (purgerarrester) due to the leakage current.

The present invention may be understood as the block or circuit diagram of fig. 2, or it may relate to various devices and methods derived from the above description, which are not limited to a particular configuration. Hereinafter, more specific configuration examples and embodiments will be described for the sake of understanding and clarifying the nature and operation of the present invention, and these are not intended to narrow the scope of the present invention.

With respect to the anomaly detector 600

If the detection speed of the abnormality detector 600 is slow, the conduction of the switch SW1 is delayed, and an overvoltage is generated during the delay, which is not preferable. Therefore, the abnormality detector 600 is required to make the abnormality detection signal S earlier than the timing at which the overvoltage suppressing circuit 500 should operate effectively (i.e., the timing at which the overvoltage is actually generated)_ABNIs effective. Therefore, the high-speed abnormality detector 600 will be described below.

Fig. 3 (a) and (b) are circuit diagrams showing a configuration example of the abnormality detector 600. The laser resonator 200 is covered by a metal housing (gas chamber) 220, and the housing 220 is grounded via a ground line 222.

The abnormality detector 600 in fig. 3 (a) determines the presence or absence of an abnormality based on the current Ix flowing through the ground line 222. More specifically, if the amplitude of the current Ix flowing through the ground exceeds a predetermined threshold, it can be determined that there is an abnormality.

The abnormality detector 600 in fig. 3 (b) determines the presence or absence of an abnormality based on the ground potential Vx of the housing 220. More specifically, if the amplitude of the potential Vx exceeds a predetermined threshold value, it can be determined that there is an abnormality.

The above is a configuration example of the abnormality detector 600. Next, the operation principle of the abnormality detector 600 will be described. Parasitic capacitances Cp exist between discharge electrode 202 and case 220 and between discharge electrode 204 and case 220. Designed resonant frequency f when the laser resonator 200 is normal_RESFlows through the laser cavity 200 (between the electrodes 202, 204), the influence of the parasitic capacitance Cp can be ignored. At this time, the current Ix flowing through the parasitic capacitance Cp and the ground line 222 is substantially zero, and the potential Vx of the case 220 is substantially equal to the ground voltage.

When the wiring connected to the discharge electrode 202 or the discharge electrode 204 is disconnected or the impedance increases, the resonance frequency of the resonance circuit 210 becomes higher than the designed value, and a high-frequency current flows. A high-frequency current flows to the ground line 222 through the parasitic capacitor Cp having a small capacitance value. Thereby, the potential Vx of the case 220 becomes nonzero.

According to the abnormality detector 600 in fig. 3 (a) and (b), the frequency shift of the resonance frequency of the resonance circuit 210 can be detected at high speed, and the switch SW1 can be turned on before (or immediately after) the overvoltage is actually generated in the power supply device 250.

The method of detecting an abnormality by the abnormality detector 600 is not limited to this. Instead of using the method with low responsiveness, the threshold for abnormality determination may be strictly set.

Fig. 4 (a) to (d) are circuit diagrams showing configuration examples of the overvoltage suppressing circuit 500. The overvoltage suppression circuit 500 of fig. 4 (a) includes a gas arrester 502. When the voltage between the terminals of the gas arrester 502 exceeds the operation start voltage, the gas arrester 502 is in a short-circuited state, and the voltage Δ V between the two ends of the overvoltage suppressing circuit 500 is suppressed.

Here, the capacitance between both ends of the overvoltage suppressing circuit 500 is preferably smaller than 1/5 of the capacitance of the pair of discharge electrodes. This is because, if the capacitance of the overvoltage suppressing circuit 500 is too large, the resonant frequency f of the resonant circuit 210 will be increased_RESThe frequency shift affects the circuit operation. From this point of view, as shown in fig. 4 (a), if the overvoltage suppressing circuit 500 is configured by the gas arrester 502 alone, the electrostatic capacitance may be excessively large.

In this case, as shown in fig. 4 (b), it is preferable to connect a plurality of overvoltage suppressing elements (surge protection elements) in series. Accordingly, the capacitance between the two ends of the overvoltage suppressing circuit 500 becomes a combined capacitance of the capacitances of the overvoltage suppressing elements, and thus can be made smaller than the capacitances of the overvoltage suppressing elements.

In more detail, the overvoltage suppression circuit 500 of fig. 4 (b) includes a gas arrester 502 and a varistor 504 connected in series with each other. In this configuration, when the high voltage Δ V is applied between both ends of the overvoltage suppressing circuit 500, the voltage between the terminals of the gas arrester 502 exceeds the operation start voltage to cause a short circuit state, and the high voltage Δ V is applied to the varistor 504. As a result, a current flows according to the I-V characteristic of the varistor 504, and the high voltage Δ V can be suppressed. Instead of the varistor 504, a general overvoltage suppression element may be used, and for example, an SPD (zinc oxide arrester) or a transient voltage suppressor (transorb) may be used.

The overvoltage suppressing circuit 500 shown in fig. 4 (a) and (b) operates in response to an overvoltage, but the overvoltage suppressing circuit 500 is not limited to this and may be a circuit for preventing an overvoltage from occurring in an abnormal open state of the laser resonator 200. More specifically, at the synchronization frequency f_RFNext, the overvoltage suppression circuit 500 may have a sufficiently higher impedance than the resonant circuit 210 to be higher than the synchronous frequency f_RFMay have a lower impedance at the frequency of (2). The overvoltage suppression circuit 500 of fig. 4 (c) includes a capacitor 506. Of capacitors 506The capacitance is 1/5 or less, preferably 1/10 or less, of the capacitance of the pair of

discharge electrodes

202 and 204. Even if an opening abnormality occurs, the capacitor 506 remains as a load, so that the resonant frequency can be prevented from becoming excessively high, and overvoltage can be suppressed.

The overvoltage suppression circuit 500 of fig. 4 (d) includes an LCR load circuit. Even if the LCR load is in an open state, the LCR load can prevent the resonant frequency from becoming too high, and overvoltage can be suppressed.

In addition, the overvoltage suppressing circuit 500 may be configured by connecting a plurality of circuits illustrated in fig. 4 (a) to (d) in parallel.

Fig. 5 is a circuit diagram showing a specific configuration example of the power supply device 250. A control signal (excitation signal) S1 for instructing a light emission period (excitation period) and a stop period is input to the laser device 100, and an intermittent operation is performed in accordance with the excitation signal S1. For example, the excitation signal S1 is a pulse signal having a repetition frequency of about several kHz and a duty ratio of about 5%.

The high-frequency power supply 400 includes an H-bridge circuit (full-bridge circuit) 402 and a step-up transformer 404. The high-frequency power supply 400 includes two sets of an H-bridge circuit 402 and a step-up transformer 404, which are connected in parallel to each other. Of course, the high-frequency power supply 400 may be constituted by only one group 401. While the excitation signal S1 is at a level (e.g., high level) indicating the excitation interval, the H-bridge circuit 402 performs a switching operation and applies the ac voltage V to the 1 st winding of the step-up transformer 404_AC. The switching frequency of the H-bridge circuit 402 is the synchronous frequency f_RFFor example, it is set to about 2 MHz. As a result, the ac voltage V is generated in the secondary winding of the step-up transformer 404_ACBoosted high-frequency voltage V_RF。

The dc power supply 300 includes a capacitor bank 302 and a charging circuit 304. The capacitor bank 302 is disposed between the DC busses 306. The charging circuit 304 charges the capacitor bank 302 to charge the voltage V of the capacitor bank 302_DCIs kept constant.

In the excitation interval, the H-bridge circuit 402 performs a switching operation, whereby the energy (charge) stored in the capacitor bank 302 is discharged, and the dc voltage V is applied_DCElectricity (D) fromThe voltage level drops. The charging circuit 304 supplies a charging current to the capacitor bank 302, thereby compensating for the dc voltage V_DCA drop in voltage level. That is, the dc power supply 300 also performs the intermittent operation in synchronization with the excitation signal S1.

The DC power supply 300 may be configured by a DC/DC converter that operates normally at all times, including the excitation period.

(use)

Next, the use of the laser device 100 will be explained. Fig. 6 is a diagram showing a laser processing apparatus 900 including the laser apparatus 100. The laser processing apparatus 900 irradiates a laser pulse 904 to the object 902 to process the object 902. The type of the object 902 is not particularly limited, and examples of the type of the processing include drilling and cutting, but the type is not limited thereto.

The laser processing apparatus 900 includes a laser apparatus 100, an optical system 910, a control device 920, and a table 930. The object 902 is placed on the table 930, and is fixed to the table 930 as necessary. The table 930 positions the object 902 based on the position control signal S2 from the controller 920 and scans the object 902 with respect to the irradiation position of the laser pulse 904. The stage 930 may have 1, 2 (XY) or 3 (XYZ) axes.

The laser apparatus 100 is excited by a trigger signal (excitation signal) S1 from the control apparatus 920 to generate a laser pulse 906. The optical system 910 irradiates the object 902 with the laser pulse 906. The optical system 910 is not particularly limited in structure, and may include a mirror group for guiding the light beam to the object 902, a lens or an aperture for shaping the light beam, and the like.

The control device 920 centrally controls the laser processing device 900. Specifically, the controller 920 intermittently outputs the excitation signal S1 to the laser device 100. Then, the controller 920 generates a position control signal S2 for controlling the table 930 based on the data (recipe) describing the processing.

The present invention has been described above with reference to the embodiments. The embodiment is an example, and those skilled in the art will understand that various modifications may be made to the combination of each constituent element or each processing step, and such modifications are also within the scope of the present invention. Hereinafter, such a modification will be described.

Next, several modifications of the arrangement of the overvoltage suppressing circuit will be described. In fig. 2, the overvoltage suppression circuit 500 is connected between the H-bridge circuit 402 and the step-up transformer 404, but is not limited thereto. Fig. 7 (a) and (b) are diagrams showing a modification of the arrangement of the overvoltage suppression circuit 500.

As shown in fig. 7 (a), the overvoltage suppression circuit 500 and the switch SW1 may be provided on the output node of the high-frequency power supply 400 (i.e., on the 2 nd side of the step-up transformer 404). Thereby, the voltage V of the secondary side 2_RFThe overvoltage of (1) can be suppressed, and further, the overvoltage on the 1 st side can be suppressed.

As shown in fig. 7 (b), the group of the overvoltage suppressing circuit 500 and the switch SW1 may be provided so as to be connected in parallel to the switches (transistors) MH and ML constituting the H-bridge circuit 402, respectively.

The overvoltage suppression circuit 500 and the switch SW1 may be provided on the laser resonator 200 side.

Next, several modifications of the abnormality detection method by the abnormality detector will be described.

The abnormality detector may determine an abnormality based on the presence or absence of output light from the laser device. If the laser device does not emit light (or the amount of light decreases), it can be determined that the laser device is abnormal.

The abnormality detector may determine an abnormality based on the current component of the resonance frequency. The current flowing through the load (resonant circuit) or the output terminal of the high-frequency power supply may be monitored, the component of the resonant frequency may be extracted from the detected value, and when the current of the resonant frequency is small, it may be determined that there is an abnormality.

The abnormality detector may determine an abnormality based on a current component other than the resonance frequency. The current flowing through the load (resonant circuit) or the output terminal of the high-frequency power supply may be monitored to extract components other than the resonant frequency from the detected value, and when the current other than the resonant frequency is large, it may be determined as abnormal.

The abnormality detector may determine an abnormality based on a drop width of the input voltage of the high-frequency power supply after irradiation. If the laser emits light normally, the electric charge stored in an output capacitor (capacitor bank) of the dc power supply is discharged, and the dc voltage drops. Therefore, the voltage of the capacitor bank is monitored, and when the voltage drop width is small, it can be determined that there is an abnormality.

The abnormality detector may determine abnormality based on noise (noi se) having a frequency higher than the resonance frequency. When the current becomes a high frequency, high frequency electromagnetic noise (Radiation noise) or conductive noise (conductive noise) increases. This noise can be detected by the antenna, and if the noise increases, it can be determined as abnormal.

The abnormality detector may determine an abnormality based on a voltage between the pair of discharge electrodes. If a sufficient voltage is not detected between both ends of the resonant circuit although a high-frequency voltage is applied, it can be determined that there is an abnormality.

The present invention has been described above with reference to the embodiments and specific terms, but the embodiments merely show one aspect of the principle and application of the present invention, and the embodiments allow a plurality of modifications and changes in arrangement without departing from the scope of the idea of the present invention defined in the claims.

Claims

1. A power supply device for driving a laser resonator including a pair of discharge electrodes, the power supply device comprising:

a high-frequency power supply that applies a high-frequency voltage to a resonance circuit including the capacitance of the pair of discharge electrodes;

an overvoltage suppression circuit that suppresses an overvoltage between both ends of the resonance circuit or an internal node of the high-frequency power supply;

a switch connected in series with the overvoltage suppression circuit; and

and an abnormality detector for turning on the switch if an abnormality is detected.

2. The power supply device according to claim 1,

the housing of the laser resonator is grounded via a ground line,

the abnormality detector detects the abnormality from a current flowing through the ground line.

3. The power supply device according to claim 1,

the housing of the laser resonator is grounded via a ground line,

the abnormality detector detects the abnormality based on a potential of the case.

4. The power supply device according to any one of claims 1 to 3,

further provided with: and if the abnormality detector detects an abnormality, notifying an external notification mechanism.

5. The power supply device according to any one of claims 1 to 4,

the high frequency power supply includes:

an inverter; and

a transformer having a 1-time winding connected to an output terminal of the inverter and a 2-time winding connected to the laser resonator,

the overvoltage suppression circuit is connected with the 1-time winding of the transformer.