JPH07131096A - High-frequency power source and laser oscillator - Google Patents

Abstract

PURPOSE:To set laser heads of a discharging load to an excellent impedance matching state before and after the discharge is started. CONSTITUTION:A high-frequency power source 34 comprises a high-frequency power source unit 11 having a DC power source 12 and an inverter 14, and a matching circuit 16 for supplying high-frequency power from the unit 11 to a laser gas-excited laser head 27 by high-frequency AC discharging. A PLL control unit 20 of the controller 30 detects an output voltage VA and an output current IA of the unit 11, and so PLL-controls an output frequency of the inverter 14 through an inverter control unit 23 that phases of the both substantially coincide. A phase detection signal level deciding unit 31 of the controller 30 stops control of the unit 20 of the unit 11 when the voltage VA and the current IA of the phase detection signal are less than predetermined levels, and instead fixes the output frequency of the unit 11 to an initial value F0 by a frequency initial value reference signal generator 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency power supply device and a laser oscillating device using the same.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional AC discharge excitation laser oscillator. That is, the high frequency power supply device 1 includes a high frequency power supply unit 2, a matching circuit 3, an output setting device 4, and a control circuit 5.

The high frequency power source section 2 converts a commercial AC power source into a high frequency power source, and its output is supplied via a matching circuit 3 between discharge electrodes 7, 7 of a laser head 6 which is a discharge load. It is like this. The laser head 6 includes resonators 8 and 8, and the resonators 8 and 8 are provided.
Emits the laser LS by photo-converting and amplifying the discharge energy between the discharge electrodes 7, 7.

In this case, the matching circuit 3 sets the voltage applied between the discharge electrodes 7 and 7 to a high voltage necessary for discharge, matches the impedance with the discharge current, and the energy of the high frequency power source is 100%. Acts to be transmitted to. Further, the control circuit 5 controls the high frequency power supply unit 2 so that the output voltage of the high frequency power supply unit 2 becomes the value set by the output setting device 4.

In the laser oscillator which excites the laser gas by such a high frequency alternating current discharge, unlike the laser oscillator which excites the laser gas by the direct current discharge, it is not necessary to expose the discharge electrodes 7, 7 in the laser gas, and therefore,
Since the electrode material does not evaporate and scatter into the laser gas during discharge, the service life of the laser gas, the discharge electrodes 7 and 7 and the resonators 8 and 8 is extended, and the operating cost is low.

[0006]

In the conventional laser oscillator, the matching between the high frequency power source impedance and the discharge impedance by the matching circuit 3 is usually performed near the power source output which is the rated output of the laser head 6. In the laser oscillator of this type, the discharge impedance seen from the high frequency power supply unit 2 is
Therefore, if the output of the high frequency power supply unit 2 is reduced from the rated output in order to convert the output of the laser light LS, the matching condition between the high frequency power supply impedance and the discharge impedance is broken, and the laser The reflected power from the head 6 to the high frequency power supply unit 2 increases, and as a result,
The loss in the high frequency power supply unit 2 increases, and the laser head 6
Oscillation instability, or a problem such as breakage of the high frequency power supply unit 2 is adversely affected.

In order to solve such a problem, the present inventor has improved and developed the following technique with a plurality of other inventors (Japanese Patent Application No. 5-89738).

The improved technique will be described below with reference to FIG. That is, the high frequency power supply unit 11 rectifies the supplied three-phase commercial AC power supply to obtain a variable DC power supply unit 1.
2 and a voltage source inverter 14 in which four SITs 14a, which are switching elements, are bridge-connected in order to obtain a high frequency power from a DC power source supplied from the DC power source unit 12 via a DC bus 13. And
An output terminal of the inverter 14 is connected via an output line 15 to an input terminal of a matching circuit 16 composed of an inverted L-shaped LC resonance circuit as impedance matching means.

The voltage detector 17 and the current detector 18 are arranged on the output line 15 and detect the output voltage and the output current of the inverter 14 of the high frequency power supply unit 11. Each output terminal has a control circuit. PLL control unit 20 in 19
Are connected to the input terminals of the high-frequency voltage detector 21 and the high-frequency current detector 22, respectively. Then, the PLL control unit 2
0 is a high-frequency voltage detector 21 and a high-frequency current detector 22.
Detects the output voltage and the output current from the voltage detector 17 and the current detector 18 as a phase detection signal, it outputs a phase difference signal corresponding to the phase difference between them, and its output terminal is an inverter. It is connected to the input terminal of the control unit 23. The inverter control unit 23 outputs a control signal according to the phase difference signal from the PLL control unit 20, and its output terminal is connected to the control input terminal of the inverter 14.

The DC power supply control section 24 of the control circuit 19 has its input terminal connected to the output terminal of the output setting device 25, which is an output setting means, and the control signal corresponding to the output setting value given from the output setting device 25. Is output, and its output terminal is the DC power supply unit 12 of the high frequency power supply unit 11.
It is connected to the control input terminal of. The high frequency power supply device 26 is configured as described above.

The laser head 27, which is a discharge load, has discharge electrodes 28, 28 facing each other, and resonators 29, 2 facing each other with a gap between the discharge electrodes 28, 28.
It has 9 points. And this laser head 27
At one of the discharge electrodes 28, the matching circuit 1
6 and the other discharge electrode 28 is grounded.

Next, the operation of this improved technique will be described. When high frequency power is output from the high frequency power supply unit 11,
The output voltage VA is made into a high voltage required for discharging by the matching circuit 16 and applied between the discharge electrodes 28, 28, and the phase of the output voltage VA is matched with the discharge current (load current) I. Therefore, a high frequency AC discharge is generated between the discharge electrodes 28, 28, and the discharge energy is generated by the resonators 29, 29.
The laser light LS is extracted after being optically converted and amplified.

Further, the output voltage V from the high frequency power source unit 11
The A and the output current IA are detected by the voltage detector 17 and the current detector 18, and are given to the high frequency voltage detection unit 21 and the high frequency current detection unit 22 of the control circuit 19. As a result, the PLL control unit 20 causes the output voltage VA and the output current IA.
And the phase difference signal is detected by the inverter control unit 2
3, the inverter control unit 23 creates a control signal of the oscillation frequency so that the phase difference becomes substantially zero, and supplies the control signal to the inverter 14. Then, the inverter 14
The output frequency is controlled so that the phase difference becomes substantially zero, that is, the phase of the output voltage VA and the output current IA substantially match by PLL control. Further, the DC power supply control unit 24 of the control circuit 19 outputs a control signal corresponding to the output set value VR from the output setting unit 25 and supplies it to the DC power supply unit 12 of the high frequency power supply unit 11. As a result, the DC power supply unit 12
Controls the output voltage VD so that the output voltage VD substantially matches the output set value VR.

Thus, the phase control by the PLL control unit 20 and the matching circuit 16 constituted by the inverted L-shaped LC resonance circuit
Although it does not make sense to perform the impedance matching by each of them independently, the matching circuit 16 causes the output voltage VA of the high-frequency power supply unit 11 and the load current I to correspond to each other substantially in a one-to-one relationship. It has been proved from the electric circuit theory that it has both functions.

On the other hand, the laser head 27, which is a discharge load during discharge, has a constant voltage characteristic. Therefore, the laser head 2
In order to control the discharge energy of No. 7, it is most effective to use the discharge current I as a parameter, and here, by controlling the output voltage VA of the high frequency power supply unit 11 as a parameter, the load current I is indirectly measured. I try to control it.

By the way, in the laser oscillator as shown in FIG. 7, the impedance before starting the discharge is different from that after starting the discharge, and the impedance seen from the outside of the matching circuit 16 is also different.

That is, in the laser oscillator, the equivalent circuit after the start of discharge is as shown in FIG. That is, the matching circuit 16 composed of an inverted L-shaped LC oscillator circuit is shown as an inductance Lm and a capacitance Cm, and the laser head 27 has a resistance component R which gives a voltage drop due to discharge, a capacitance between the discharge electrodes 28 and 28, and a discharge. The electrodes 28, 28 and the capacitance component C which is the sum of the capacitances of the electrodes 28 themselves. The equivalent circuit before the start of discharge is as shown in FIG. That is, the laser head 27
, There is no resistance component R that gives a voltage drop, and there is only a capacitance component C.

Therefore, if the frequency F (hereinafter referred to as PLL frequency) that provides impedance matching after the start of discharge is given as the initial value of the output frequency of the high-frequency output of the high-frequency power supply section 11, the impedance is transiently changed before the start of discharge. There is a problem that a matching state occurs.

Therefore, in order to solve such a problem, it is conceivable to give the resonance frequency F0 (the resonance frequency of the equivalent circuit of FIG. 9) before the start of discharge as the initial value of the output frequency of the high frequency power supply section 11. . In this case, the fluctuation of the resonance frequency at the start of discharge of the laser oscillator is
Since the L control has a speed sufficient to follow, theoretically, it is possible to operate the laser oscillator in a good impedance matching state both before and after the start of discharge.

By the way, in FIG. 7, when the output setting of the high frequency power supply device 26 is set to zero during the operation of the laser oscillator, the PLL control unit 2 in the control device 19 is operated.
The output voltage VA and the output current IA detected by the high frequency voltage detection unit 21 and the high frequency current detection unit 22 of 0 are both zero. When the output setting of the high frequency power supply 26 is smaller than the rated output during the operation of the laser oscillator, the signal levels of the output voltage VA and the output current IA detected by the PLL control unit 20 are also as described above. It becomes small and contains many error components. Therefore, in the actual operation, when the output setting of the high frequency power supply device 26 is less than a certain value, the PLL control is performed due to an error component included in the output voltage VA and the output current IA detected by the PLL control unit 20. Normal operation cannot be guaranteed, that is, the output frequency of the high-frequency power supply device 26 does not become a value that causes the output voltage VA and the output current IA to substantially match in phase.

As described above, since the output voltage VA and the output current IA detected by the PLL control unit 20 are below a certain level when the laser head 27 is not in the discharging operation, even if the high frequency power supply unit is used. Even if the resonance frequency F0 before the start of discharge is given as the initial value of the output frequency of 11, this resonance frequency F0 becomes meaningless for the PLL control, and is good both before and after the start of discharge. The purpose of maintaining the impedance matching state cannot be achieved.

On the other hand, in the laser oscillator shown in FIG. 7, the load impedance has an individual difference mainly depending on the value of the capacitance component of the load. That is, in the equivalent circuit after the start of discharge (FIG. 8) and the equivalent circuit before the start of discharge (FIG. 9) of the laser oscillator, the capacitance between the discharge electrodes 28, 28 and the capacitance of the discharge electrodes 28, 28 themselves are combined. Since the capacitance component C is mainly determined by the shape of the discharge electrodes 28, 28, the capacitance component of the laser oscillator is the discharge electrodes 28, 2
8 has a solid difference according to the shape.

In this case, there is no problem as long as the individual difference in the load impedance of the laser oscillator is within a range that can be adjusted by the fluctuation of the output frequency of the high frequency power supply unit 11, but it is adjusted with the upper limit value of the output frequency. It may deviate from what is possible. In this way, when the individual difference in the load impedance cannot be adjusted between the upper limit value and the lower limit value of the output frequency of the high frequency power supply unit 11, the output frequency is the upper limit value, the lower limit value or a harmonic of the original PLL frequency. Or it will be either a subharmonic value. And in such cases,
It is necessary to adjust the values of the impedance Lm and the capacitance Cm of the matching circuit 16 so that impedance matching can be realized between the upper limit value and the lower limit value of the output frequency that is the variable range of the high frequency output of the high frequency power supply unit 11.

Even if the inductance Lm and the capacitance Cm of the matching circuit 16 are adjusted as described above, the capacitance component of the load impedance changes due to a change in the composition of the laser gas or a change in the shape of the discharge electrodes 28, 28. It is possible to do it. Especially, in these cases, it is often related to some abnormal phenomenon, and in this sense, it is important to understand the PLL frequency.

However, in the configuration shown in FIG. 7, when impedance matching between the high frequency power supply unit 11 and the laser head 27 cannot be realized between the upper limit value and the lower limit value of the output frequency of the high frequency power supply unit 11. However, this cannot be determined. In particular, when the pull-in by the harmonic of the original PLL frequency or the subharmonic occurs between the upper limit value and the lower limit value of the output frequency of the high frequency power supply unit 11, it is very distinct from the normal pull-in. It was difficult.

Therefore, a first object of the present invention is to provide a high frequency power supply device capable of achieving a good impedance matching state before and after the start of discharge of a discharge load.

The second object of the present invention is to judge the impedance matching with the discharge load when it may not be realized between the upper limit value and the lower limit value of the output frequency. It is to provide a high frequency power supply device.

A third object of the present invention is to provide a laser oscillating device capable of achieving a good impedance matching state both before and after the start of discharge of the laser head.

A fourth object of the present invention is to judge if impedance matching with the laser head may not be realized between the upper limit value and the lower limit value of the output frequency of the high frequency power supply device. A laser oscillating device capable of performing the above is provided.

[0030]

According to a first aspect of the present invention, there is provided a high frequency power supply device, which is installed between a high frequency power supply part for converting a commercial AC power supply into a high frequency power supply, and the high frequency power supply part and a discharge load. And the output voltage of the high frequency power supply unit are approximately 1
An impedance matching unit that matches the relationship of 1 and an output voltage and an output current of the high frequency power supply unit are detected as a phase detection signal, and the output frequency of the high frequency power supply unit is controlled so that these phases substantially match each other. A control means for setting the high-frequency output of the high-frequency power supply section using the output voltage as a parameter, wherein the control means controls the output voltage of the high-frequency power supply section when the phase difference detection signal is below a certain level. The control of the output frequency for substantially matching the phase with the output current is stopped, and instead, the output frequency of the high-frequency power supply unit is fixed to a preset frequency initial value in the range between the upper limit value and the lower limit value. It is characterized in that it is configured to do.

The high-frequency power supply device according to a second aspect is similar to the high-frequency power source device according to the first aspect, in which a high-frequency power source portion, impedance matching means and control means are provided, and also switch means which is operated from the outside is provided. When the switch means is operated, the control of the output frequency for making the phases of the output voltage and the output current of the high frequency power supply unit substantially match is stopped, and instead, the output frequency of the high frequency power supply unit is changed to It is characterized in that it is configured to be fixed to any one of the upper limit value, the lower limit value and the frequency initial value preset in these ranges.

In the high frequency power supply device according to a third aspect of the present invention, the control means is informed as to whether or not the control of the output frequency for making the phases of the output voltage and the output current of the high frequency power supply part substantially coincide with each other. It is characterized in that it is configured to output a notification signal.

A laser oscillating device according to a fourth aspect is characterized in that the high frequency power supply device according to the first, second or third aspect is used to excite a laser gas by a high frequency AC discharge.

[0034]

According to the high frequency power supply device of the present invention, the control means predetermines the output frequency of the high frequency power supply unit when the phase detection signal (output voltage and output current of the high frequency power supply unit) is less than a certain level. The frequency is fixed to the initial value and the operation is performed. In other words, the control means causes the operation by the PLL control only when the phase detection signal is at a certain level or higher. Therefore, a good impedance matching state can be achieved before and after the discharge of the discharge load is started.

In this case, the control means outputs a notification signal when the phase detection signal is below a certain level (when the PLL control is not normally performed), so that the operation based on the frequency initial value depends on the presence or absence of the notification signal. It is possible for the operator to determine whether the operation is based on the PLL control or the PLL control (claim 3).

According to the high frequency power supply device of claim 2,
The control means, when the switch means is operated,
The control of the output frequency for substantially matching the phases of the output voltage and the output current of the high frequency power supply unit is stopped, and instead, the output frequency of the high frequency power supply unit is preset with its upper limit value and lower limit value. It is fixed to either the initial frequency value.
Therefore, thereafter, by restarting the PLL control and measuring the change in the output frequency of the high frequency power supply unit and observing the frequency pull-in state, it is possible to determine whether or not the PLL control is normally performed.

In this case, the control means outputs the notification signal when the frequency pull-in by the PLL control is completed, so that the operator can know the frequency pull-in completion (claim 3).

According to the laser oscillator of the fourth aspect,
With respect to the laser head, which is a discharge load, the same effects as those of claim 1, 2 or 3 can be obtained.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. 1. In FIG. 1, the same parts as those in FIG. Will be described only.

That is, like the control circuit 19, the control circuit 30 as the control means has the PLL control section 20, the inverter control section 23 and the DC power supply control section 24, and also has the phase detection signal level determination section 31 and the initial frequency value. (F0) The reference signal generator 32 and the changeover switch 33 are included. Then, in the changeover switch 33, the movable contact piece c is connected to the input terminal of the inverter control section 23, and one fixed contact piece b is connected.
Is connected to the output terminal of the PLL control unit 20, and the other output terminal a is connected to the output terminal of the frequency initial value reference signal generation unit 32. Further, both input terminals of the phase detection signal level determination unit 31 are connected to output terminals of the voltage detector 17 and the current detector 18, respectively.

In this case, the phase detection signal level determination unit 31
Inputs the output voltage VA and the output current IA from the voltage detector 17 and the current detector 18 as a phase detection signal,
When these are respectively above a certain level, the contact pieces (c-b) of the changeover switch 33 are turned on, and when these are below a certain level respectively, the contact piece (c-b) of the changeover switch 33 is turned on.
A) is turned on, and an interface output signal IFSa is output from the output terminal as a notification signal, whereby an unillustrated notification device such as a notification lamp is turned on.

Then, the control circuit 30 includes the high frequency power source unit 1.
1 and matching circuit 16 together with high frequency power supply 34
It is what constitutes.

Next, the operation of this embodiment will be described. still,
The operation when the laser head 27, which is a discharge load, oscillates normally and outputs the laser light LS is the same as in the improved technique shown in FIG. 7. In this case, the contact piece (c-b) of the changeover switch 33 is used. ) Is turned on.

If the output voltage VA and the output current IA, which are the phase detection signals detected by the phase detection signal level determination unit 31, have not reached the respective fixed levels, the phase detection signal level determination unit 31 operates the changeover switch 33. Contact piece (c-
b) is turned off and the contact piece (c-a) is turned on, and the interface output signal IFSa is output from the output terminal.
Is output.

Therefore, the contact piece (c-
By turning off during b), the PLL control of the high frequency power supply unit 11 by the PLL control unit 20 is stopped, and instead, by turning on between the contact pieces (ca) of the changeover switch 33, the frequency initial value reference signal generating unit 32 is turned on. The frequency initial value (F0) reference signal from is supplied to the inverter control unit 23. This allows
The inverter 14 is controlled so that the output frequency of the high frequency output is fixed to the frequency initial value F0 (the initial value F0 is set between the upper limit value FH and the lower limit value FL).

After that, when the output voltage VA and the output current IA of the high frequency output become higher than a certain level due to the operation of the high frequency power supply device 34 fixed to the frequency initial value F0, the phase detection signal level determination unit 31 , Changeover switch 3
The three contact pieces (c-a) are turned off and the contact pieces (c-b) are turned on, and the output of the interface output signal IFSa from the output terminal is stopped. Therefore, the phase difference signal from the PLL control unit 20 is given to the inverter control unit 23 by turning on the contact pieces (c-b) of the changeover switch 33, and thus the PLL of the high frequency power supply unit 11 is turned on.
Control is resumed.

As described above, according to this embodiment, the output voltage VA and the output current IA of the high frequency output of the high frequency power supply section 11 are obtained.
Is less than a certain level, the PL of the high frequency power supply 11 is
The L control is stopped, and instead, the high frequency power supply unit 11 is fixedly operated so that its output frequency becomes a predetermined frequency initial value F0, and the output voltage VA and the output current IA are above a certain level. At this time, since the high frequency power supply unit 11 is operated by the PLL control, it is possible to operate the laser head 27 in a good impedance matching state before and after the start of discharge.

Moreover, when the output voltage VA and the output current IA from the high-frequency power supply unit 11 are below a certain level, the phase detection signal level determination unit 31 outputs the interface output signal IFSa. By the presence or absence of the above, the operator can determine whether the high frequency power supply unit 11 is currently operating at the frequency initial value F0 or the PLL control.

FIG. 2 shows a second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Only the different parts will be described below.

That is, unlike the control circuit 30, the control circuit 35 as the control means is different from the control circuit 30 in that the phase detection signal level determination section 3 is provided.
1 and a changeover switch 33 are not provided, and instead, a frequency upper limit reference signal generating unit 36 and a lower limit value (for generating a frequency upper limit reference signal that gives an upper limit value (FH) of the output frequency of the high frequency power supply unit 11 are generated. In addition to having a frequency lower limit value reference signal generating section 37 for generating a frequency lower limit value reference signal for giving FL), a selection switch 38 which is a switch means operated from the outside is provided.

In the selection switch 38, the first fixed contact piece a is connected to the output terminal of the PLL control section 20, and the second fixed contact piece b is connected to the output terminal of the frequency initial value reference signal generation section 32. , The third fixed contact piece c is connected to the output terminal of the frequency upper limit value reference signal generating section 36, and the fourth fixed contact piece d is connected to the output terminal of the frequency lower limit value reference signal generating section 37. e is connected to the input terminal of the inverter control unit 23. The PLL control unit 20 outputs the interface output signal IFSb as a notification signal when the frequency pull-in is completed by the PLL control, and this causes a notifying device (not shown) such as a notification lamp to be turned on. The control circuit 35 constitutes a high frequency power supply device 39 together with the high frequency power supply section 11 and the matching circuit 16.

Next, the operation of the second embodiment will be described with reference to FIGS. 3 and 4. High frequency power supply 1
1 and the laser head 27 may not be impedance-matched between the upper limit value FH and the lower limit value FL of the output frequency of the high frequency power supply unit 11, or a harmonic of the original PLL frequency F. When the pull-in by the subharmonic occurs, it is not stable as compared with the normal pull-in of frequency. Therefore, by operating the selection switch 38, the frequency can be disturbed to make the determination.

That is, by operating the selection switch 38 from the outside, the contact piece (e-a) is turned off, and the contact piece (e-a) is turned off.
-B), the contact pieces (e-c) or the contact pieces (ed) are turned on. Therefore, the contact piece (e-
The PLL control by the PLL control unit 20 is stopped by turning off a) and the high frequency power supply unit 11 is turned on by turning on between the contact pieces (e-b), between the contact pieces (e-c) or between the contact pieces (e-d). Output frequency is fixed to an initial value F0, an upper limit value FH or a lower limit value FL. After that, when the selection switch 38 is operated again to turn on the contact pieces (e-a), the PLL control of the high frequency power supply unit 11 by the PLL control unit 20 is restarted. In this state, it is possible to determine whether or not the PLL control is normally performed by measuring the frequency change over time and observing the frequency pull-in state.

This state will be described with reference to FIGS.
The original PLL frequency F is lower than the lower limit value FL of the output frequency of the high frequency power supply unit 11, and the harmonic F ′, which is one of the harmonics of the original PLL frequency F, is the upper limit value FH of the output frequency of the harmonic power supply unit 11. And the lower limit value FL (see FIG. 3).
reference). In this case, the high frequency power supply unit 1 is selected by operating the selection switch 38 to select the frequency upper limit reference signal generating unit 36.
When the output frequency of 1 is set to the upper limit value FH, the harmonic F ′ may cause pull-in (state (A) of FIG. 3), but the lower limit frequency reference signal generator 37 is selected by operating the selection switch 38. Then, when the output frequency of the high frequency power supply unit 11 is set to the lower limit value FL, the pull-in occurs at the original PLL frequency F. However, since the output frequency of the high frequency power supply unit 11 does not become lower than the lower limit value FL, the output frequency is fixed to the lower limit value FL (state (B) of FIG. 3).

Although not shown, the original PLL frequency F is higher than the upper limit value FH of the output frequency of the high frequency power supply section 11, and the subharmonic which is one of the subharmonics of the original PLL frequency F is the high frequency power supply. When the output frequency of the high frequency power supply unit 11 is set to the lower limit value FL by operating the selection switch 38 when the output frequency of the unit 11 is between the upper limit value FH and the lower limit value FL, pull-in occurs due to subharmonic. But there is
When the output frequency of the high frequency power supply unit 11 is set to the upper limit value FH by operating the selection switch 38, the original PLL frequency F causes pull-in. However, the high frequency power supply unit 11
Since the output frequency of does not exceed the upper limit value FH, the output frequency is fixed to the upper limit value FH.

On the other hand, when the original PLL frequency F is between the upper limit value FL and the lower limit value FL of the output frequency of the high frequency power supply unit 11 (see FIG. 4), the output frequency of the high frequency power supply unit 11 is selected by the selection switch 38. When the upper limit value FH is set (state (C) of FIG. 4) and when the lower limit value FL is set (FIG. 4).
In any of the (d) states, the PLL frequency F causes pull-in, and the PLL control unit 20 outputs the interface output signal IFSb from the output terminal.

Therefore, according to the second embodiment, the impedance matching between the high frequency power source section 11 and the laser head 27, which is a discharge load, is between the upper limit value FH and the lower limit value FL of the output frequency of the high frequency power source section 11. If there is a possibility that it has not been realized by the above, it can be judged by operating the selection switch 38 and measuring the output frequency of the high frequency power supply section 11.

Moreover, when the pull-in is completed at the PLL frequency based on the operation of the selection switch 38, the PL
Since the L control unit 20 outputs the interface output signal IFSb to light the notification lamp, it is not necessary to measure the output frequency of the high frequency power supply unit 11 in this case.

FIG. 5 shows a third embodiment of the present invention. The same parts as those in FIGS. 1 and 2 are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described below.

The control circuit 40 as the control means is composed of the components of the control circuit 30 shown in FIG. 1 and the control circuit 35 shown in FIG.
Of the fixed contact piece c of the changeover switch 38.
Is connected to the first fixed contact piece a of the selection switch 38.

Therefore, the contact piece (e-
When the switch a) is turned on, the same effect as that of the first embodiment shown in FIG. 1 is obtained, and the switch (e-a) of the selection switch 38 is turned off and the switch (e-). When b), contact piece (e-c) or contact piece (ed) is turned on, the same operation and effect as those of the second embodiment shown in FIG. 2 can be obtained.

The present invention is not limited to the embodiments described above and shown in the drawings. For example, the high frequency power supply device is applied not only to the laser oscillation device but also to all discharge loads requiring a high frequency power supply. Needless to say, the present invention can be appropriately modified and implemented without departing from the spirit of the invention.

[0063]

Since the present invention is as described above, it has the following effects. According to the high frequency power supply device of claim 1, when the phase detection signal is below a certain level, the control for making the phases of the output voltage and the output current of the high frequency power supply unit substantially coincide with each other is stopped, and the high frequency power supply unit is also provided. Since the output frequency of is fixed to a predetermined frequency initial value, a good impedance matching state can be achieved both before and after the discharge of the discharge load is started.

According to the high frequency power supply device of claim 2,
When the switch means is operated, the control for making the phases of the output voltage and the output current of the high frequency power supply unit substantially coincide with each other is stopped, and the output frequency of the high frequency power supply unit is set to an upper limit value, a lower limit value or a predetermined value. Since it is fixed to one of the initial frequency values, impedance matching with a discharge load may not be realized when the output frequency of the high frequency power supply section is between the upper limit value and the lower limit value.
This can be determined.

According to the high frequency power supply device of claim 3,
Since a notification signal for notifying whether or not the control for substantially matching the phases of the output voltage and the output current of the high frequency power supply unit is normally performed, it is convenient in terms of work.

According to the laser oscillator of the fourth aspect,
Since the high frequency power supply device according to claim 1, 2 or 3 is used for exciting the high frequency discharge of the laser gas, the effect obtained from the configuration according to claim 1, 2 or 3 can be obtained even in the case of a laser head.

[Brief description of drawings]

FIG. 1 is an electrical configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an electrical configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a frequency shift diagram when PLL control is not normally performed.

FIG. 4 is a frequency shift diagram when PLL control is normally performed.

FIG. 5 is an electrical configuration diagram showing a third embodiment of the present invention.

FIG. 6 is an electrical configuration diagram showing a conventional example.

FIG. 7 is an electrical configuration diagram showing an improved technique.

FIG. 8 is an equivalent circuit diagram when the discharge is lit.

FIG. 9 is an equivalent circuit diagram when the discharge is not lit.

[Explanation of symbols]

In the drawings, 11 is a high frequency power supply unit, 12 is a DC power supply unit, 14
Is an inverter, 16 is a matching circuit (impedance matching means), 20 is a PLL control unit, 21 is a high frequency voltage detection unit, 22 is a high frequency current detection unit, 23 is an inverter control unit, 24 is a DC power supply control unit, and 25 is output setting. , 27 is a laser head (dischargeable load), 28 is a discharge electrode, 29 is a resonator, 30 is a control circuit (control means), 31 is a phase detection signal level determination unit, 32 is a frequency initial value reference signal generation unit, 34 is a high frequency power supply device, 35 is a control circuit (control means), 36 is a frequency upper limit value reference signal generator, 37 is a frequency lower limit value reference signal generator, 38 is a selection switch (switch means), 39 is a high frequency power supply device, Reference numeral 40 denotes a control circuit (control means), and 41 denotes a high frequency power supply device.

Claims (4)

[Claims] 1. A high-frequency power supply unit for converting a commercial AC power supply into a high-frequency power supply; and a high-frequency power supply unit installed between the high-frequency power supply unit and a discharge load, wherein a load current and an output voltage of the high-frequency power supply unit are approximately 1: 1. The impedance matching means to match the relationship of, the output voltage and the output current of the high-frequency power supply unit is detected as a phase detection signal, and the output frequency of the high-frequency power supply unit is controlled so that these phases substantially match, And a control means for setting the high frequency output of the high frequency power supply using the output voltage as a parameter, wherein the control means outputs the output voltage and the output current of the high frequency power supply when the phase detection signal is below a certain level. Stop the control of the output frequency to make the phases of
Instead, the high-frequency power supply device is configured to fix the output frequency of the high-frequency power supply unit to a preset frequency initial value in the range between the upper limit value and the lower limit value. 2. A high frequency power source section for converting a commercial AC power source into a high frequency power source, and a high frequency power source section installed between the high frequency power source section and a discharge load, wherein a load current and an output voltage of the high frequency power source section are approximately 1: 1. The impedance matching means to match the relationship of, the output voltage and the output current of the high-frequency power supply unit is detected as a phase detection signal, and the output frequency of the high-frequency power supply unit is controlled so that these phases substantially match, The high frequency power supply section comprises a control means for setting a high frequency output using the output voltage as a parameter, and a switch means operated from the outside. The control means, when the switch means is operated, the high frequency power supply section. Control of the output frequency for making the phases of the output voltage and the output current substantially coincide with each other, and instead, the output frequency of the high frequency power supply unit is set to the upper limit value. High-frequency power supply apparatus characterized by being configured to secure the one of the lower limit and the preset frequency initial value in these ranges. 3. The control means outputs a notification signal for notifying whether or not the control of the output frequency for making the phases of the output voltage and the output current of the high frequency power supply section substantially coincide with each other is normally performed. Claim 1 characterized by the above.
Or the high frequency power supply device according to 2. 4. A laser oscillating device, wherein the high frequency power supply device according to claim 1, 2 or 3 is used to excite a laser gas by a high frequency AC discharge.