JPH0644653B2 - Laser controller - Google Patents

Description

The present invention relates to a laser output control device, and more particularly to a duty control of a pulse and a switching function to a continuous wave.

[Prior Art] FIG. 3 is a block diagram showing a configuration example of a conventional laser control device. In the figure, (1) is an output setter, (2) is an operational amplifier that amplifies the difference between the setting signal from the output setter and the laser output feedback signal, and (3) is the output signal of the operational amplifier (2). And an operational amplifier that amplifies the difference between the discharge current feedback signal, (4) a switching element that opens and closes the circuit, (5) a drive circuit that amplifies the signal from the operational amplifier (3), and (6) a power Switching circuit composed of transistors, etc., (7) power supply, (8a) and (8b) electrodes, (9a) and (9b) mirrors, (10)
Is a laser beam, (11) is an output sensor that detects the laser output and converts it into an electric signal, (12) is a current detector that detects the discharge current, and (13) sets the time ratio of ON and OFF of the pulse. Duty setter, (14) a frequency setter that sets the pulse repetition frequency, (15) a triangular wave generation circuit that generates a triangular wave by the signal of the frequency setter (14), (16) a triangular wave generation circuit (15) 2 is a voltage comparator for comparing the output signal of 1) with the setting signal from the duty setting device (13).

Further, FIGS. 4 (a) to (c) and FIGS. 5 (a) to (d).
FIG. 4 is a waveform diagram for explaining the operation of FIG. 3, and the operation of the circuit of FIG. 3 will be described with reference to these waveforms.

Triangle wave generation circuit by the setting signal from the frequency setter (14)
(15) generates a triangular wave of a certain frequency. When the set value of the frequency setting device (14) is low, (a) in Fig. 4 (a)
When the set value is high, a triangular wave having a low frequency is generated as in the state, and a triangular wave having a high frequency is generated as in the state (b) in FIG. The voltage comparator (16) is a triangular wave generation circuit.
The output signal of (15) and the output signal of the duty setting device (13) are compared with each other, and when the latter voltage is larger than the former voltage, (a) and (b) in FIG. ) Outputs a pulse signal as shown in the state. This pulse signal is supplied to the switching element (4), and when the pulse has a high level, the element is closed, and when the pulse has a low level, the element is open.

The setting signal of the output setting device (1) and the laser output feedback signal from the output sensor (11) are calculated in the operational amplifier (2) and controlled so that a constant laser output is obtained.
In this case, the response time of the output sensor (11) is generally slower than 0.1 second, so the response time of the operational amplifier (2) is also delayed to match the response time of the output sensor (11). Therefore, in the case of pulse output with a frequency of about 100 Hz, the output signal of the operational amplifier (2) is in a substantially flat signal state. The operational amplifier (3) in the next stage performs a comparison operation between the output signal of the operational amplifier (2) in the previous stage and the discharge current feedback signal from the current detector (12) and controls so that the discharge current becomes constant. . In this case, since the response speed of the current detector (12) is high, it is possible to obtain the feedback signal of the discharge current corresponding to the pulsed laser output. Therefore, the response time of the operational amplifier (3) is fast, and the output signal of the operational amplifier (3) has a waveform in response to the pulse as shown in the states of (a) and (b) of FIG. Become. The output signal of the operational amplifier (3) is connected to the drive circuit (5) when the switching element (4) is closed. The drive circuit (5) amplifies the output signal of the operational amplifier (3) and controls the switching circuit (6) by the output signal. When the switching circuit (6) closes the circuit, a higher voltage than the power supply (7) is applied between the electrodes (8a) and (8b), the laser (10) is generated, and output through the mirror (9a). To be done. Part of the output of the laser (10) is also output to the output sensor (11) via the mirror (9a), and the output sensor (11) detects the laser output and outputs it as an electric signal.

Generally, in the case of pulsed laser output, a higher output peak value is more stable in many cases. However, in the control method by the device of FIG. 3, if the duty setter (13) is adjusted and the ON time of the pulse is lengthened, (a) of FIG.
The laser output value changes from the state to the state (b), and the average output value of the laser output is constant, but the peak output value decreases. For this reason, laser processing became unstable, and it was necessary to adjust the output setting device (1) again to increase the peak output value.

[Problems to be Solved by the Invention] In the above laser control device, in order to secure the peak value of the laser output at a desired value, the duty setting device (1
The output setting device (1) needs to be readjusted every time the adjustment of (3) is made, which causes a problem that the adjustment work is complicated.

The present invention has been made to solve such a problem. During pulse operation, even if the laser output value is adjusted by changing the duty of the pulse, it can be adjusted without affecting the peak output value. The purpose is to obtain a laser control device.

Another object of the present invention is to obtain an automatic protection device for preventing damage to the laser oscillator when the peak output value and the average output value can be adjusted independently as described above.

[Means for Solving Problems] A laser control device according to claim 1 of the present invention includes an average output setting device capable of variably setting an average output of laser oscillation and an average output value of laser oscillation. Of an average output detector, a first operational amplifier for amplifying a difference signal between an average output detection value detected by the average output detector and a setting value set in the average output setting device, and a frequency variable setting device. A triangular wave generating circuit that generates a triangular wave whose frequency is variable according to a set value is compared with the amplitude values of the output signal of the first operational amplifier and the output signal of the triangular wave generating circuit, and the duty determined by the timing of the magnitude relationship is compared. The voltage comparator that outputs a pulse signal of the ratio, the peak current setting device that can variably set the peak current value of the pulse oscillation laser when the oscillation mode of the laser is pulse, and the laser A current detector that detects a peak current value due to pulse oscillation; a second operational amplifier that amplifies a difference signal between the current detection value detected by the current detector and the set value set in the peak current setting device; Based on the pulse signal of the duty ratio output from the voltage comparator, pulse oscillation is performed so that the average output value of the laser that performs pulse oscillation becomes the average output set value and based on the output signal of the second operational amplifier. The laser control means controls the pulse oscillation of the laser independently so that the peak current value of the laser becomes the peak current setting value.

Further, a laser control device according to claim 2 of the present invention is an average output setter capable of variably setting an average output of laser oscillation, an average output detector for detecting an average output value of laser oscillation, and the average. A first operational amplifier that amplifies a difference signal between the average output detection value detected by the output detector and the set value set in the average output setter; and a laser for switching the oscillation mode of the laser from pulse to continuous wave A switching setter capable of variably setting an average output value, a triangular wave generating circuit for generating a triangular wave whose frequency is variable according to a set value of the frequency variable setter, an output signal of the first operational amplifier and an output of the triangular wave generating circuit. A first voltage comparator for comparing an amplitude value with a signal and outputting a pulse signal having a duty ratio determined by the timing of the magnitude relationship, and an output signal value of the first operational amplifier The second voltage comparison that compares the setting value of the switching setting device and outputs a control signal that makes the laser oscillation mode continuous wave oscillation or pulse oscillation depending on whether the former signal value exceeds the latter setting value. And a peak current setting device capable of variably setting the peak current value of the laser that performs pulse oscillation when the laser oscillation mode is pulse, and a pulse oscillation control signal is supplied from the second voltage comparator. When the switching circuit is closed and the control signal for continuous wave oscillation is supplied from the first switching circuit that outputs the input set value of the peak current setting device and the second voltage comparator, The circuit is closed, the second switching circuit that outputs the input output signal of the first operational amplifier, the current detector that detects the discharge current value due to the oscillation of the laser, and the current detector at one end of the input Current detected by The output signal of the first switching circuit or the second switching circuit is supplied to the other end of the input in response to the control signal of the pulse oscillation or the continuous wave oscillation output from the second voltage comparator. And a second operational amplifier that amplifies the difference signal between both ends of the input and the second voltage comparator outputs a pulse oscillation control signal, the duty output by the first voltage comparator. Based on the pulse signal of the ratio so that the average output value of the pulse-oscillated laser becomes the average output set value, and the peak current value of the pulse-oscillated laser is the peak based on the output signal of the second operational amplifier. When the pulse oscillation of the laser is controlled independently so that the current setting value is obtained, and when the second voltage comparator outputs the control signal of the continuous wave oscillation, the second voltage comparator outputs the second signal via the first operational amplifier. Performance of And a laser control means for controlling the continuous wave oscillation of the laser so that the average output value of the continuous wave laser becomes the average output set value based on the output signal of the operational amplifier.

[Operation] In the invention according to claim 1, the average output of the laser oscillation can be variably set by using the average output setting device, and the average output detector detects the average output value of the laser oscillation. The first operational amplifier amplifies a difference signal between the average output value detected by the average output detector and the set value set in the average output setter. The triangular wave generation circuit generates a triangular wave whose frequency is variable according to the set value of the frequency variable setter. The voltage comparator compares the amplitude values of the output signal of the first operational amplifier and the output signal of the triangular wave generation circuit, and outputs a pulse signal having a duty ratio determined by the timing of the magnitude relationship. Further, when the oscillation mode of the laser is pulse, the peak current setting device can variably set the peak current value of the pulse-oscillated laser, and the current detector detects the peak current value due to the pulse oscillation of the laser. The second operational amplifier amplifies a difference signal between the current detection value detected by the current detector and the set value set in the peak current setting device. The laser control means, based on the pulse signal of the duty ratio output from the voltage comparator, so that the average output value of the laser pulse oscillation becomes the average output set value,
Further, based on the output signal of the second operational amplifier, the pulse oscillations of the lasers are independently controlled so that the peak current value of the laser pulse-oscillating becomes the peak current setting value.

Further, in the invention according to claim 2,
The average output of the laser oscillation can be variably set using the average output setter, and the average output detector detects the average output value of the laser oscillation. The first operational amplifier amplifies a difference signal between the average output detection value detected by the average output detector and the set value set in the average output setter. Then, the switching setter can be used to variably set the average output value of the laser for switching the laser oscillation form from pulse to continuous wave. The triangular wave generation circuit generates a triangular wave whose frequency is variable according to the set value of the frequency variable setter. The first voltage comparator compares the amplitude values of the output signal of the first operational amplifier and the output signal of the triangular wave generating circuit, and outputs a pulse signal having a duty ratio determined by the timing of the magnitude relationship. The second voltage comparator compares the output signal value of the first operational amplifier with the set value of the switching setter, and oscillates the laser depending on whether the former signal value exceeds the latter set value. It outputs a control signal whose form is continuous wave oscillation or pulse oscillation. Further, the peak current setting device can be used to variably set the peak current value of the pulse-oscillated laser when the oscillation mode of the laser is pulse. The first switching circuit closes when the control signal for pulse oscillation is supplied from the second voltage comparator, and outputs the input set value of the peak current setting device. When the control signal for continuous wave oscillation is supplied from the second voltage comparator, the second switching circuit closes and outputs the input output signal of the first operational amplifier. The current detector detects a discharge current value due to laser oscillation. The second operational amplifier is supplied with a current detection value detected by the current detector at one end, and has a pulse oscillation or continuous wave oscillation control signal output from the second voltage comparator at the other end. The output signal of the first opening / closing circuit or the second opening / closing circuit is supplied in response to the above, and the difference signal between both ends of the input is amplified. When the second voltage comparator outputs a pulse oscillation control signal, the laser control means determines that the average output value of the pulse-oscillated laser is based on the pulse signal of the duty ratio output by the first voltage comparator. So that the average output set value is obtained, and the peak current value of the laser that performs pulse oscillation becomes the peak current set value based on the output signal of the second operational amplifier,
When the pulse oscillation of the laser is controlled independently, and when the second voltage comparator outputs the control signal of the continuous wave oscillation, based on the output signal of the second operational amplifier via the first operational amplifier, The continuous wave oscillation of the laser is controlled so that the average output value of the continuous wave oscillation laser becomes the average output set value.

[Embodiment] FIG. 1 is a block diagram according to an embodiment of the present invention. (1) to (12) and (14) to (16) are the same as those of the conventional apparatus of FIG. is there. (20) is the peak current setting device, (21a) is the switching element that closes the circuit at the time of pulse output, (21
b) is a switching element that closes the circuit during continuous wave output,
(22) is a pulse / continuous wave switching setter, (23) is a voltage comparator for comparing the output signals of the switching setter (22) and the operational amplifier (2), (24) is a signal inverter, and (25) ) Is an OR circuit.

The states (a), (b), and (c) of FIGS. 2A to 2F are waveform diagrams for explaining the operation of FIG. 1, and refer to these waveforms. The operation of the circuit shown in FIG. 1 will be described.

First, each waveform when the set value of the output setter (1) is small is shown in the state (a) of FIG. When the set value of the output setter (1) is small, the output signal of the operational amplifier (2) is also in the low level state, and this waveform is shown in (a). The output signal of the operational amplifier (2) is connected to one input of the voltage comparator (16), and the triangular wave generating circuit is connected to the other input as in the conventional device.
The output signal of (15) is connected. The voltage comparator (16) generates a pulse signal at the output when the former signal level is higher than the latter signal level. In this case, the output of the operational amplifier (2) is at a low level, so the output pulse width is short and
The pulse duty value is small. This waveform is shown in (b). The set value from the pulse / continuous wave switching setting device (22) is connected to one input of the voltage comparator (23), and the output signal of the operational amplifier (2) is connected to the other input. And as a result of the former signal level being higher than the latter signal level,
The output signal of the voltage comparator (23) is in a low level state, and this waveform is shown in (c). The output signal of the voltage comparator (23) is the switching element (21b), the signal inverter (24) and the OR circuit (2
It is connected to one end of the input of 7). Voltage comparator
Since the output signal of (23) is low level, the circuit of the switching element (21b) is opened and the signal inverted by the signal inverter (24) to high level is applied as shown in (d). The switching circuit (21b) is closed. The setting value of the peak current setting device (20) is the switching circuit (21
Since it is connected to the input side of a) and the circuit is now closed, the peak current setting value is applied to one of the inputs of the operational amplifier (3) and the other input, the current detector ( 12)
The comparison operation with the discharge current feedback signal is performed in the same operational amplifier. The output signal of the operational amplifier (3) is connected to the input side of the switching element (4).

Further, since the output signal of the voltage comparator (16) is input to the other end of the input of the OR circuit (25) and the output signal of the voltage comparator (23) is at a low level now, the voltage comparator ( The same signal as the output signal of 16) is obtained at the output side, and its waveform is shown in (e). The output signal of this OR circuit (25) is a switching element.
Applied to (4), it opens and closes the circuit. Therefore, in this case, the circuit of the switching element (4) is substantially opened and closed by the output signal of the voltage comparator (16). The output signal of the operational amplifier (3) is connected to the input side of the switching element (4), and the output side thereof is connected to the drive circuit (5). The drive circuit (5) drives the switching circuit (6),
(6) applies a high-voltage power supply to the electrodes to oscillate the laser, and the output is the set value of the output setter (1), frequency setter (14), and peak current setter (20), and the laser output feedback. A series of operations controlled by the signal and the discharge current feedback signal are the same as in the conventional device. This laser output waveform is
Shown in.

Next, the waveform when the set value of the output setting device (1) is made relatively large will be described in the state (b) of FIG. Output setting device (1)
When the set value of is slightly increased, the output signal of the operational amplifier (2) becomes a medium level, and this state is shown in (a). In the voltage comparator (16), as a result of the output signal of the operational amplifier (2) connected to one of its inputs becoming a medium level, the pulse width of the output pulse signal becomes longer than in the state (a). , The pulse duty value is increasing. The waveform in this state is shown in (b). In the voltage comparator (23),
Since the output signal of the operational amplifier (2) connected to one of the inputs is still smaller than the set value of the pulse and continuous wave switching setter (22), the output signal does not change and is in a low level state, The waveform is shown in (c). Similarly, the output signal of the signal inverter (24) that receives the output signal of the voltage comparator (23) does not change, and its waveform is shown in (d). Therefore, the circuit states of the switching elements (21a) and (21b) driven by the two signals do not change. The output signal of the OR circuit (25) is also the same as that of the voltage comparator (1b), and its waveform is shown in (e).

In this state (b), since the set value of the peak current setting device (20) does not change, the peak output value of the laser pulse output does not change and is the same as the value in the state (a), but the voltage comparator (1
Since the duty of the pulse signal which is the output of 6) is increasing, the average output value of the laser is also increasing. The waveform of the laser output (10) in this case is shown in (f).

Differences between the present invention and the conventional device in the states (a) and (b) will be described. First, since the setting value of the peak current setting device (20) is configured to be connected to the operational amplifier (3) via the switching element (21a), the peak output value of the laser output can be adjusted by adjusting the peak current setting value. Control became possible. In addition, the setting value of the output setter (1) is changed to the operational amplifier (2).
It is connected to one input of the voltage comparator (16) via and is compared with the triangular wave signal which is the other input, and the duty value of the pulse output signal obtained as a result can be changed. By adjusting it, it became possible to control the average output value of the laser output.

Moreover, the peak output value and average output value of this laser are the separate setters, the peak current setter (20) and the output setter (1).
It became possible to control independently by adjusting and respectively.

Finally, the waveform when the set value of the output setter (1) is further increased is shown in the state (c) of FIG. 2 and will be described. Output setting device
When the set value of (1) is further increased, the output signal of the operational amplifier (2) increases to a high level, and this state is shown in (a).
The output signal of this operational amplifier (2) is connected to one input of the voltage comparator (23) and is set to the setting value of the pulse and continuous wave switching setter (22) connected to the other input. Since this time is larger than this time, the output signal of the voltage comparator (23) is inverted,
The high level state is continuously entered. This waveform is shown in (c). The switching element (21b) driven by the output signal of the voltage comparator (23) is closed, and the switching element (21a) driven via the signal inverter (24) shown in the waveform (d) is The circuit opens. Since the OR circuit (25) is supplied with the high level continuous signal which is the output of the voltage comparator (23) at one input, the output of the voltage comparator (16) shown in the waveform (b) at the other input. Even if the signal is supplied, the output signal becomes a continuous high level signal, and its waveform is shown in (e). Since the switching element (4) is driven by the continuous high level signal which is the output of the OR circuit (25), the circuit is closed continuously.

Therefore, in this (c) state, first, the peak current setting device
The setting signal from (20) is disconnected from the circuit by the switching element (21a). Then, the setting signal from the output setter (1) is a switching element (4) in which the circuit is closed continuously with the operational amplifier (2), the switching element (21a) and the operational amplifier (3).
The control system of the laser is established by the signal path that is supplied to the drive circuit (5) via the. Further, in the (a) state and the (b) state, the circuit is opened and closed to cause the pulsed oscillation of the laser.Since the switching element (4) continuously closes the circuit in the (c) state, Laser oscillation becomes a continuous wave, and its output value is controlled by the value set by the output setter (1). This waveform is shown in (f).

In this way, when the duty of the laser pulse in state (b) exceeds a certain value, the pulse control function is stopped,
By shifting to the state (c) and switching the laser to the continuous wave output, it is possible to prevent the allowable maximum average output from being exceeded.

Generally, the usage of laser oscillator is (a) state and (b)
In many cases, like the state, the maximum peak output value is larger than the maximum average output value. In this case, the heat-resistant capacity of the power transistor or the like used in the switching circuit (6) is selected based on the maximum average output value. For this reason, when the duty of the laser pulse having the maximum peak output value exceeds a certain value, the average output value exceeds the allowable maximum average output value, and there is a possibility that the power transistor or the like may be damaged beyond the heat resistance limit. However, in the present invention, as described in the embodiment, when the duty of the laser pulse is increased and the average output set value is increased, from the state (b) to the state (c) at a certain limit value.
By shifting to the state and changing the laser oscillation from the pulse to the continuous wave, the average output is suppressed.

As a result, damage to equipment such as power transistors can be prevented, and equipment with low heat-resistant capacity can be used, thus improving the economical efficiency of the apparatus.

Although the laser output is detected by using the partial reflection type mirror in the above-mentioned embodiment, an output sensor for detecting the laser output by another method such as a Bees spirit may be used.

Moreover, although it has been described that the switching circuit (6) is composed of a power transistor or the like, other circuit switching elements such as a power MOSFET may be used.

The first claim of the present invention is a laser control device when the oscillation mode of the laser is pulse oscillation. In FIG. 1, the laser control device in this case is configured,
An example of an average output setter is an output setter 1, an example of an average output setter is an output sensor 11, an example of a first operational amplifier is an operational amplifier 2, and an example of a triangular wave generation circuit is a triangular wave generation circuit including a frequency setter 14. 15. An example of voltage comparator is voltage comparator
16. An example of the peak current setting device is the peak current setting device 20, an example of the current detector is the current detector 12, and an example of the second operational amplifier is the operational amplifier 3. An example of the laser control means includes a switching element 4, a drive circuit 5, an opening / closing circuit 6 and a power supply 7, and a control signal input from a voltage comparator 16 and an operational amplifier 3 and a laser current detector 12 and an output. This is a control device in which a feedback loop is formed by the feedback signals respectively fed back from the sensor 11.

The second aspect of the present invention is a laser control device having two types of laser oscillation modes, pulse oscillation and continuous wave oscillation, and automatic switching means for this oscillation mode. In FIG. 1, the laser control device in this case is configured,
An example of the switching setting device is the switching setting device 22, an example of the first voltage comparator is the voltage comparator 16, an example of the second voltage comparator is the voltage comparator 23, and an example of the first switching circuit is a signal inverter. The switching element (21a) including 24, and an example of the second switching circuit is the switching element (21b). An example of the laser control means includes an OR circuit 25, a switching element 4, a drive circuit 5, an opening / closing circuit 6 and a power supply 7, and a control signal and a laser current detector respectively input from the OR circuit 25 and the operational amplifier 3. This is a control device in which a feedback loop is formed by feedback signals respectively fed back from 12 and the output sensor 11. Correspondence between the other constituent elements and the embodiment is the same as that in the case of the first term.

[Effect of the Invention] As described in detail above, according to the present invention, the pulsed laser output is controlled by controlling the peak output value by the peak current setting device and by setting the output setting device to control the pulse duty. Since the control of the average output value by means of (1) can be carried out independently, it is easy to set the processing conditions and there is an effect that stable laser processing can be performed.

Further, the pulse output condition is limited, and when the duty of the output pulse exceeds a certain value, the output is automatically changed to the continuous wave output, so that there is an effect of preventing damage to the device and improving the economical efficiency.

[Brief description of drawings]

FIG. 1 is a block diagram showing a laser control device according to an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation of FIG. 1, and FIG. 3 is a block diagram showing a conventional laser control device. FIG. 4 is a waveform diagram for explaining the pulse generating circuit of FIG. 3, and FIG. 5 is a waveform diagram for explaining the operation of FIG. In the figure, (1) is an output setting device, (2) and (3) are operational amplifiers, (4) is a switching element, (5) is a drive circuit, (6) is a switching circuit, (7) is a power supply, ( 8a) and (8b) are electrodes, (9a) and (9
b) is a mirror, (10) is a laser beam, (11) is an output sensor, (12)
Is a current detector, (13) is a duty setting device, (14) is a frequency setting device, (15) is a triangular wave generating circuit, (16) and (23) are voltage comparators, (20) is a peak current setting device, (21a) and (21b) are switching elements, (22) is a switching setting device, (24) is a signal inverter,
(25) is an OR circuit. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (2)

[Claims] 1. An average output setting device capable of variably setting an average output of laser oscillation, an average output detector detecting an average output value of laser oscillation, an average output detection value detected by the average output detector and the average. A first operational amplifier for amplifying a difference signal from a set value set in the output setter; a triangular wave generation circuit for generating a triangular wave whose frequency is variable according to the set value of the frequency variable setter; and the first operation A voltage comparator that compares the amplitude value of the output signal of the amplifier and the output signal of the triangular wave generation circuit, and outputs a pulse signal with a duty ratio determined by the timing of the magnitude relationship, and when the laser oscillation mode is pulse, A peak current setting device capable of variably setting a peak current value of a pulsed laser, a current detector for detecting a peak current value of a laser pulsed oscillation, and the current detector are A second operational amplifier that amplifies a difference signal between the detected current detection value and the set value set in the peak current setting device, and a laser that pulsates based on a pulse signal of a duty ratio output from the voltage comparator. Pulse of the laser so that the average output value of the laser becomes the average output setting value, and the peak current value of the laser that performs pulse oscillation becomes the peak current setting value based on the output signal of the second operational amplifier. A laser control device comprising: a laser control unit that controls oscillation independently of each other. 2. An average output setting device capable of variably setting an average output of laser oscillation, an average output detector detecting an average output value of laser oscillation, an average output detection value detected by the average output detector and the average. A first operational amplifier that amplifies the difference signal from the set value set in the output setter, a switching setter that can variably set the average output value of the laser that should switch the laser oscillation form from pulse to continuous wave, and frequency A triangular wave generating circuit that generates a triangular wave whose frequency is variable according to the set value of the variable setter is compared with the amplitude values of the output signal of the first operational amplifier and the output signal of the triangular wave generating circuit, and the magnitude relationship is compared. A first voltage comparator that outputs a pulse signal having a duty ratio determined by timing is compared with an output signal value of the first operational amplifier and a setting value of the switching setting device to obtain the former signal. Second voltage comparator that outputs a control signal that makes the laser oscillation mode continuous wave oscillation or pulse oscillation depending on whether or not the latter setting value is exceeded, and pulse oscillation when the laser oscillation mode is pulse A peak current setting device capable of variably setting a peak current value of a laser, and the peak current setting device to which a switching circuit is closed and inputted when a pulse oscillation control signal is supplied from the second voltage comparator. Of the first operational amplifier that outputs the set value of the first operational amplifier and the first open / close circuit that is closed when the control signal for continuous wave oscillation is supplied from the second voltage comparator. The second open / close circuit that outputs the output signal, the current detector that detects the discharge current value due to the oscillation of the laser, the current detection value detected by the current detector is supplied to one end of the input, and the other end of the input is supplied. , The second The output signal of the first switching circuit or the second switching circuit is supplied in response to the pulse oscillation or continuous wave oscillation control signal output from the voltage comparator of FIG. When the second operational amplifier and the second voltage comparator output the pulse oscillation control signal, the average output value of the laser that pulse-oscillates based on the pulse signal of the duty ratio output from the first voltage comparator. Is set to the average output set value, and based on the output signal of the second operational amplifier, the pulse oscillation of the laser is independently controlled so that the peak current value of the pulse-oscillated laser becomes the peak current set value. When the second voltage comparator outputs a control signal for continuous wave oscillation, the continuous wave oscillation is performed based on the output signal of the second operational amplifier via the first operational amplifier. And a laser control means for controlling continuous wave oscillation of the laser so that the average output value of the laser becomes the average output set value.