JP4942710B2 - Power supply for gas laser - Google Patents

Description

  The present invention relates to a gas laser power supply apparatus for supplying pulse power for causing a gas laser oscillator to perform predetermined pulse laser oscillation.

  The gas laser power supply device is a device that supplies pulsed power from an inverter circuit to a gas laser oscillator and outputs pulse laser light from the gas laser oscillator.

  By the way, depending on the type of object to be processed, such as a printed circuit board, which requires fine processing, a pulse laser beam with a high peak and short pulse and a pulse laser beam with a low peak length pulse are required. There is something to do. In other words, in a power supply device that controls a gas laser oscillator (for example, a carbon dioxide laser oscillator) used for microfabrication of a printed circuit board or the like, a control capability capable of outputting a pulse laser beam having a different pulse width to the gas laser oscillator is required. The The required pulse width is in the range of about 1 μs to several tens of μs.

  Here, the pulse width of the pulse laser beam, which is the time width of the laser output, is determined by the number of pulses of the pulse power given from the inverter circuit to the gas laser oscillator, that is, the number of switching times of the switching elements constituting the inverter circuit. Increasing the number of switching times of the element increases switching loss. On the other hand, in the gas laser oscillator, since there is a light resistance intensity limit of the mirror constituting the resonator, it is necessary to limit the change width of the pulse width of the output pulse laser light.

  Thus, for example, Patent Document 1 proposes a thinning processing technique that can change the pulse width of pulsed laser light without increasing the number of pulses of pulse power applied to the gas laser oscillator. This thinning processing technology switches the number of pulses of pulse power supplied to the gas laser oscillator to the number of pulses thinned out according to the pulse width setting of the control parameter. Is supplied to the gas laser, and in the case of thinning out, the pulsed power of the number of tooth-missing pulses corresponding to the number of thinning out is supplied to the gas laser oscillator, and the pulse laser light of the low peak length pulse is output. It is to make it.

  Regarding switching loss, when supplying continuous pulse power to the gas laser oscillator in order to obtain a high peak short pulse laser beam, when the gas laser oscillator becomes stable, the output current to the gas laser oscillator, Since the output voltage is in a substantially constant and stable state, even when the thinning processing technique proposed in Patent Document 1 is adopted, the circuit can be configured so that the loss at the time of switching on is reduced.

  For example, if the techniques proposed in Patent Document 2 and Patent Document 3 are used, the load voltage and the load current are detected, and the voltage applied to both ends of the switching element is determined as much as possible based on the electrical signal. It is to adopt a configuration that controls at a timing that decreases.

  Alternatively, the loss at the time of switching on can also be reduced by determining the circuit constant so that the switching element is turned on in a state where the voltage applied to both ends of the switching element is as small as possible at the time of switching on. Specifically, the boost transformer for boosting the output of the inverter circuit and the electrode of the gas laser oscillator connected to the secondary side of the boost transformer constitute a series resonance circuit of LCR. By adjusting, the circuit constant is determined so that the loss when switching on is reduced.

Japanese Patent No. 3846573 JP 2002-209377 A Japanese Patent No. 3396369

  However, when supplying pulsed power that has been thinned to obtain a pulse laser beam with a low peak length pulse to the gas laser oscillator, no current or voltage is supplied to the gas laser oscillator at the timing when the pulse is thinned out. The load state such as the gas temperature of the oscillator is different from the case where continuous pulse power is supplied. Therefore, the waveforms of current and voltage supplied to the gas laser oscillator by switching immediately after the thinned timing are different from those in the case of supplying continuous pulse power.

  In other words, even when adjusting as described above so as to reduce the switching loss when supplying continuous pulse power to the gas laser oscillator, the loss at the time of switching on increases when the pulse laser light of low peak length pulse is obtained. There is a problem of doing.

  To solve this problem, if the techniques proposed in Patent Document 2 and Patent Document 3 described above are used, it is necessary to monitor the electrical signal and control the next timing. It is not possible to reduce the loss at the time of switching on from the state that is not. As described above, in the conventional technique, when the gas laser oscillator does not supply current or voltage but the load state changes from the continuous supply of pulse power as in the case of performing thinning processing of pulse power. Therefore, it is not possible to perform control that reduces loss during switching.

  The present invention has been made in view of the above, and for a gas laser that can reduce the loss at the time of switching on, even when supplying pulsed power that has been thinned out, as well as when supplying continuous pulsed power without thinning out It aims at obtaining a power supply device.

  In order to achieve the above-described object, the present invention provides a command pulse group and a mode selection signal based on a repetitive pulse frequency and a pulse width indicated by a control parameter that defines characteristics of a pulsed laser beam output from a gas laser oscillator. A control circuit for outputting, a thinning circuit for performing a process for thinning and thinning pulses from the command pulse group according to an operation mode indicated by the mode selection signal, and outputting them as a command pulse group after the thinning process; An on-time adjustment circuit that outputs the on-time of the post-decimation command pulse group in accordance with the operation mode indicated by the mode selection signal, and after the decimation process in which the on-time is adjusted by the on-time adjustment circuit A pulse power generation circuit that generates pulse power to be supplied to the gas laser oscillator based on a command pulse group. It is characterized in.

  According to the present invention, when the pulse power subjected to the thinning process is supplied, the loss at the time of switching on can be reduced as in the case where the continuous pulse power is supplied without performing the thinning process.

  Exemplary embodiments of a power supply device for a gas laser according to the present invention will be explained below in detail with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a gas laser power supply device according to Embodiment 1 of the present invention. In FIG. 1, a gas laser power supply device (hereinafter simply referred to as “power supply device”) 1 according to the first embodiment has a gas laser oscillator 2 as a control target. The gas laser oscillator 2 is, for example, a carbon dioxide laser oscillator.

  The power supply device 1 includes a rectifier circuit 4 to which an AC power supply 3 is connected, an inverter circuit 5, a step-up transformer 6, an on-time adjusting circuit 7, a thinning circuit 8, and a control circuit 9. The gas laser oscillator 2 is connected to the secondary side of the step-up transformer 6.

  In the gas laser oscillator 2, an electrode 10 and a total reflection mirror 11 and a partial reflection mirror 12 constituting an optical resonator are arranged in a housing filled with a laser medium (mixed gas). The electrode 10 is disposed facing the longitudinal direction of the housing. The total reflection mirror 11 is disposed on one end side (the step-up transformer 6 side) of the electrode 10 in the longitudinal direction, and the partial reflection mirror 12 is disposed on the other end side (output end side) of the electrode 10 in the longitudinal direction. A space between the counter electrodes 10 in the optical resonator is a discharge space 13.

  In the power supply device 1, the rectifier circuit 4 performs full-wave rectification on the AC power from the AC power source 3 and converts it into DC power, thereby forming a DC power source for the inverter circuit 5. In the inverter circuit 5, the switching element in the full bridge circuit as shown in FIG. 2 performs an on / off operation based on the switching element on / off signal 18 from the on-time adjusting circuit 7, and pulse power is supplied from the DC power source presented by the rectifier circuit 4. Is generated. The step-up transformer 6 boosts the pulse power generated by the inverter circuit 5 to a level at which discharge is possible in the discharge space 13 and applies it to the electrode 10 of the gas laser oscillator 2. As a result, in the gas laser oscillator 2, a pulse discharge is generated in the discharge space 13, and a pulsed laser beam based on the laser oscillation is amplified by the optical resonator, and the pulsed laser beam 14 is output from the partial reflection mirror 12 to the outside. . The rectifier circuit 4, the inverter circuit 5, and the step-up transformer 6 as a whole correspond to the pulse power generation circuit according to the first aspect.

  FIG. 2 is a diagram illustrating a configuration example of the inverter circuit 5 shown in FIG. 1 and its load. As shown in FIG. 2, the inverter circuit 5 includes switching elements 19A and 19B and switching elements 19C and 19D connected in series between the positive output terminal and the negative output terminal of the rectifier circuit 4 in parallel. The load 22 is connected to the connection ends of the elements 19A and 19B and the connection ends of the switching elements 19C and 19D. The switching elements 19A, 19B, 19C, and 19D are, for example, MOSFETs, and the stray capacitance elements 20A, 20B, 20C, and 20D and the free-wheeling diodes 21A, 21B, 21C, and 21D are connected to the switching elements 19A, 19B, 19C, and 19D, respectively.

  The inverter circuit 5 is configured such that the set of the switching elements 19A and 19D and the set of the switching elements 19B and 19C are alternately turned on and off in accordance with the switching element on / off signal 18 from the on-time adjusting circuit 7 so that the load 22 In other words, pulse power is supplied to the gas laser oscillator 2 through the step-up transformer 6.

  The load 22 is composed of a series resonance circuit of an inductance component 22A included in the step-up transformer 6, a capacitance component 22B formed between the electrodes 10 of the gas laser oscillator 2, and a resistance component 22C included in the electrode 10 of the gas laser oscillator 2. Is done.

  In this embodiment, in order to reduce switching loss when supplying continuous pulse power without thinning processing to the gas laser oscillator 2, the voltages at both ends when the switching elements 19A, 19B, 19C, and 19D are turned on are approximately 0V. The time constant of the series resonant circuit is adjusted in advance by the method shown in FIG. The on-time adjusting circuit 7 reduces the switching loss when the thinned pulse power is supplied to the gas laser oscillator 2.

  First, the time constant adjustment of the series resonance circuit constituting the load 22 will be described with reference to FIG. FIG. 3 is a diagram for explaining time constant adjustment in the case of supplying continuous pulse power that is not thinned out. In FIG. 3, when the switching elements 19A and 19D and the switching elements 19B and 19C are alternately switched, the voltage across the switching element 19C is (1) before the time constant adjustment and (2) The transition state after constant adjustment is shown.

  In FIG. 3A, in the section a, the switching elements 19A and 19D are turned on, so that the voltage across the switching element 19C rises to the rectified voltage. In the next section b, since the switching elements 19A and 19D are turned off, the voltage across the switching element 19C is the inductance value L of the inductance component 22A of the series resonance circuit constituting the load 22 and the capacitance component 22B. The voltage of the switching element 19C decreases to the voltage X (V) according to a time constant determined by the capacitance value C and the resistance value R of the resistance component 22C. In this example, the switching element 19C is turned on in the state of the voltage difference at the time of the voltage X (V) when it becomes the section c. In the interval c, the switching element 19C is turned on, so the voltage across the switching element 19C is 0V. In the section d, since the switching elements 19B and 19C are turned off, the voltage across the switching element 19C rises according to the time constant of the series resonance circuit constituting the load 22.

  Here, the loss when the switching element 16C is turned on increases as the voltage X (V) applied to both ends of the switching element 19C at the time of turning on becomes larger. For this reason, the time constant of the voltage drop in the section b is adjusted so that the voltage applied to both ends of the switching element 19C at the time of ON is substantially 0V.

  3 (2) shortens the time constant of the series resonance circuit constituting the load 22 compared with the case shown in FIG. 3 (1), and the voltage X (V) applied to both ends when the switching element 19C is turned on is almost equal. This is an example of 0V. For the adjustment, in order to increase or decrease the inductance value L of the series resonance circuit constituting the load 22, the addition of the reactor, the inductor component of the step-up transformer is decreased, or the capacitance value C is adjusted by adjusting the distance between the electrodes 10. Adjust it. As described above, the loss at the time when the switching element is turned on in the case of generating continuous pulse power that is not thinned out is reduced.

  In FIG. 1, a control parameter that defines the characteristics of the pulsed laser light 14 to be output to the gas laser oscillator 2 is input to the control circuit 9 from the outside. This control parameter includes a repetition pulse frequency setting of the pulse laser beam 14 and a pulse width setting of the pulse laser beam 14. Based on the repetitive pulse frequency and pulse width included in this control parameter input from the outside, the control circuit 9 determines the number of pulses when the pulse power output from the inverter circuit 5 is not thinned out (maximum in the inverter circuit 5). A designated pulse group 15 that designates the number of times of switching), and a mode selection signal 16 that designates one of the operation mode in which the number of pulses of the pulse power output from the inverter circuit 5 is not thinned out and the operation mode in which it is thinned out are generated. .

  The mode selection signal 16 indicates an operation mode in which, for example, only one of the “H” level and the “L” level is not thinned when there is only one type of thinning process, A binary level signal indicating a thinning-out operation mode can be used. In addition, when there are two or more types of thinning-out processing, the mode selection signal 16 is a binary data signal indicating an operation mode that is not thinned out and any one of two or more types of thinning-out processing. You can also.

  A designated pulse group 15 and a mode selection signal 16 are input from the control circuit 9 to the thinning circuit 8. Further, the mode selection signal 16 is input from the control circuit 9 and the output (designated pulse group after the thinning process) 17 of the thinning circuit 8 is input to the on-time adjusting circuit 7.

  In the present example, when the thinning circuit 8 has only one type of thinning processing, the designated pulse group input in parallel from the control circuit 9 according to the signal level of the mode selection signal 16 input from the control circuit 9. 15 is directly applied to the on-time adjusting circuit 7 as a post-thinning-designated pulse group 17 without being thinned out, and a process of thinning out a predetermined number of pulses at a predetermined interval is performed. 17, the operation given to the on-time adjusting circuit 7 is performed.

  The thinning circuit 8 includes a thinning table that is referred to when performing thinning processing when two or more types of thinning processing are performed. In the thinning table, the number and interval of pulses to be thinned from the designated pulse group 15 are set for each designated value of the mode selection signal 16 that designates the thinning operation mode. That is, when the mode selection signal 16 input from the control circuit 9 designates the operation mode to be thinned out, the thinning circuit 8 extracts the number of pulses to be thinned out and the interval from the thinning table according to the designated content of the mode selection signal 16. The designated pulse group 15 input in parallel is subjected to a thinning process, and the designated pulse group 17 after the thinning process is given to the on-time adjusting circuit 7.

  When the mode selection signal 16 indicates an operation mode to be thinned out, the on-time adjustment circuit 7 adjusts the on-time time constant of each pulse in the designated pulse group 17 after the thinning-out process and creates the switching element on / off signal 18. The voltage is applied to each gate terminal of the switching elements 19A, 19B, 19C, 19D of the inverter circuit 5. As a result, the switching loss in the case of supplying the thinned pulse power to the gas laser oscillator 2 is reduced.

  When the mode selection signal 16 indicates an operation mode in which the mode selection signal 16 is not thinned, the on-time adjusting circuit 7 basically creates the switching element on / off signal 18 directly from the designated pulse group 17 after the thinning process, The voltage is applied to each gate terminal of the switching elements 19A, 19B, 19C, and 19D of the circuit 5. As described above, this is because the time constant of the series resonance circuit constituting the load 22 is adjusted when supplying continuous pulse power without thinning processing to the gas laser oscillator 2. However, in actual application, the on-time time constant of each pulse in the designated pulse group 17 after the decimation processing is the same as when the mode selection signal 16 indicates the decimation operation mode in relation to the dead time or the like. Is adjusted to create a switching element on / off signal 18 and apply it to each gate terminal of the switching elements 19A, 19B, 19C, 19D of the inverter circuit 5.

  FIG. 4 is a circuit diagram showing a configuration example of the on-time adjusting circuit 7 shown in FIG. FIG. 4 shows a configuration example in which only one type of thinning process is performed. That is, in FIG. 4, the mode selection signal 16 is a binary level signal. For example, when the mode selection signal 16 is “H” level, it indicates that the thinned-out designated pulse group 17 from the thinning circuit 8 is not thinned, and when it is “L” level, the thinning circuit 8 It is assumed that the designated pulse group 17 after thinning-out processing indicates that thinning-out is being performed.

  The selector 30 to which the mode selection signal 16 is input has two output terminals, one of which is connected to the control terminal of the switch 28A and the other of which is connected to the control terminal of the switch 28B. Yes.

  One end of each of the switches 28A and 28B is connected to the output terminal of the logic IC 31A to which the command pulse group 17 after the thinning process is input, and the cathode terminal of the diode 32 is connected. One end of each of the resistors 27A and 27B is connected to the other end of each of the switches 28A and 28B. The other ends of the resistors 27A and 27B are commonly connected to one end of a capacitor 29, and the other end of the capacitor 29 is connected to circuit ground.

  An anode terminal of the diode 32 and an input terminal of the logic IC 31B are connected to a connection line between the other ends of the resistors 27A and 27B and one end of the capacitor 29. The switching element on / off signal 18 is output from the output terminal of the logic IC 31 </ b> B to the inverter circuit 5.

  Here, the resistors 27A and 27B have different resistance values. The series circuit of the resistor 27A and the capacitor 29 constitutes a filter circuit having a certain time constant, and the series circuit of the resistor 27A and the capacitor 29 constitutes a filter circuit having another time constant.

  In the configuration shown in FIG. 4, the logic IC 31A logically inverts the post-thinning-designated pulse group 17 from the thinning circuit 8 and applies it to one end of each of the switches 28A and 28B. The logic IC 31B logically inverts the pulse train appearing at the connection end between the other ends of the resistors 27A and 27B and one end of the capacitor 29, and outputs it to the inverter circuit 5 as the switching element on / off signal 18.

  When the mode selection signal 16 is at the “H” level, the selector 30 outputs a control signal to the control terminal of the switch 28A, for example, to close the switch 28A, and between the output terminal of the logic IC 31A and the circuit ground, The filter circuit by the capacitor 27A and the capacitor 29 is connected. Thus, the rising characteristics of the trailing edge of each pulse obtained by logically inverting the designated pulse group 17 after the thinning process from the thinning circuit 8, that is, the falling characteristics of each pulse of the designated pulse group 17 after the thinning process from the thinning circuit 8 are obtained. It is adjusted by the time constant of the filter circuit composed of the resistor 27A and the capacitor 29. In the present example, the command pulse group 17 after the thinning process is the command pulse group 15 because the thinning process is not performed.

  Further, when the mode selection signal 16 is at the “L” level, the selector 30 outputs a control signal to the control terminal of the switch 28B to close the switch 28B, and between the output terminal of the logic IC 31A and circuit ground, The filter circuit by the device 27B and the capacitor 29 is connected. As a result, the falling characteristics of the tooth-missing pulses of the post-decimation command pulse group 17 in which the decimation process is being performed are adjusted by the time constant of the filter circuit composed of the resistor 27B and the capacitor 29.

  The operation will be described below with reference to FIGS. First, FIG. 5 is a diagram for explaining a loss at the time of switching on in the case of supplying the thinned pulse power without adjusting the on time. In other words, for the sake of easy understanding, only the time constant of the load 22 is adjusted to supply continuous pulse power without thinning processing. A specific description will be given of the occurrence of loss. FIG. 5 shows a transition state of the voltage across the switching element 19C when the group of the switching elements 19A and 19D and the group of the switching elements 19B and 19C are alternately switched.

  When performing the pulse thinning process, the discharge space 13 temporarily stops discharging, so that the discharge space 13 is the same as the initial state. When the discharge space 13 is in the initial state, it is difficult for the discharge current to flow. Therefore, the discharge current described in paragraph “0008” of FIG. 3 and FIG. 23 is reduced, and the capacitance value between the electrodes 10 decreases. As the series resonance frequency increases. When the resonance frequency is increased, naturally, the voltage drop when the switching element is turned off is also delayed.

  For this reason, in a state where the time constant of the voltage drop in the section b shown in FIG. 3 is adjusted so as to reduce the loss when the switching element is turned on in accordance with the case where the pulse power is continuously output, When the thinning process is performed, the voltage decreases slowly and, as shown in FIG. 5, the waveform is switched before the voltage decreases.

  In the section a in FIG. 5, the voltage across the switching element 19 </ b> A that is on is 0 V, and the off operation is performed, as in the section a in FIG. 3 that shows the case where pulse power is continuously supplied. The voltage across the switching element 19C has increased to the rectified voltage. In the next section b, as described with reference to FIG. 3, since the time constant of the voltage drop is long, the voltage drop is slow and the voltage X (V) before the voltage across the switching element 19C becomes 0V is reached. Thus, the switching element 19C is turned on to enter the section c, and a loss occurs when the switching is turned on.

  The interval d resonates and decreases with a time constant determined by the inductance component L, the capacitance component C, the resistance component R, and the capacitance values of the stray capacitance elements 20A and 20D of the load 22, and the switching element 19C and the switching element 19D The voltage settles into a state where the voltage is divided in a direct current. Although the waveform is originally shown by a broken line, the voltage is clamped to a rectified voltage and has a waveform as shown by a solid line because there are freewheeling diodes 21A to 21D. The section e is a state where the voltage is divided in a DC manner between the switching element 19C and the switching element 19D, and no current flows through the electrode 10, that is, the discharge is stopped. As described above, when the series resonance circuit of the load 22 is adjusted so that the loss at the time of switching on when the continuous pulse power is supplied decreases, the loss at the time of switching on when the thinned pulse power is supplied. Does not decrease.

  Next, FIG. 6 is a diagram for explaining an operation in which the ON time of the command pulse group 17 after the thinning process is changed by the ON time adjusting circuit 7 shown in FIG.

  In FIG. 6, the waveform indicated by the symbol A indicates the waveform of the pulse of the post-decimation command pulse group 17 that is input to the logic IC 31 </ b> A illustrated in FIG. 4. A pulse waveform obtained by logically inverting the pulse waveform A is input to the logic IC 31B shown in FIG. 4 through a filter circuit including one of the resistors 28A and 28B selected by the selector 30 and the capacitor 29. The This is the waveform indicated by symbol B. Reference numeral B indicates the relationship between the rising waveform of the trailing edge of the pulse input to the logic IC 31B shown in FIG. 4 through the filter circuit selected by the selector 30 and the threshold voltage of the logic IC 31B.

  As shown by symbol B, the trailing edge of the pulse input to the logic IC 31B shown in FIG. 4 through the filter circuit selected by the selector 30 shows a characteristic that rises from the on-time of the waveform shown by symbol A. The rising characteristics of the trailing edge waveforms are characteristics 34 and 35 having a delay due to the time constant of the filter circuit selected by the selector 30. When the time constant of the filter circuit is small, the trailing edge of the pulse input to the logic IC 31B rises quickly and exceeds the threshold voltage of the logic IC 31B as in the characteristic 34, but when the time constant of the filter circuit is large, the characteristic Since the trailing edge of the pulse input to the logic IC 31B rises later like 35, the time until the threshold voltage of the logic IC 31B is exceeded is longer than in the case of the characteristic 34.

  In the case of the characteristic 34 in which the time constant of the filter circuit selected by the selector 30 is small, the output of the logic IC 31B has a waveform indicated by the symbol C, and the ON time thereof is slightly longer than the ON time of the waveform indicated by the symbol A. It has become. In the case of the characteristic 35 having a large time constant of the filter circuit selected by the selector 30, the output of the logic IC 31B has a waveform indicated by the symbol D. The waveform indicated by reference sign D has a longer on-time than the waveform indicated by reference sign C.

  In this example, the control circuit 9 selects the filter circuit having a large time constant when the thinning process is not performed, and selects the filter circuit having a small time constant when performing the thinning process. Outputs the mode selection signal 16 to the on-time adjusting circuit 7.

  As described above, the switching element on / off signal 18 which is a gate signal output from the on-time adjusting circuit 7 to the inverter circuit 5 is obtained by changing the command pulse group 17 after the thinning process input from the thinning circuit 8 to the value of the mode selection signal 16. Accordingly, the signal is adjusted so that the ON time becomes longer.

  Here, there is no delay in the rising characteristic of the leading edge of the output waveform of the logic IC 31B as shown in the waveform indicated by symbol C and symbol D in FIG. The diode 32 is provided so as not to change the timing at which the switching element on / off signal 18 rises.

  When the output of the logic IC 31A changes from the “L” level state to the “H” level state, the diode 32 is turned off, so that the capacitor 29 is charged via the switch and the resistor. Therefore, the filter circuit selected by the selector 30 becomes effective, and the rising edge of the trailing edge of the input pulse to the logic IC 31B is delayed as indicated by reference numeral B.

  On the contrary, when the output of the logic IC 31A changes from the “H” level state to the “L” level state, the diode 32 is turned on, so that the capacitor is connected via the diode 32 without passing through the switch and the resistor. Since the charge charge is discharged from 29, the state is the same as when no filter circuit is provided. Therefore, the falling characteristic of the leading edge of the input pulse to the logic IC 31B falls with almost no delay time. That is, regarding the rising edge of the leading edge of the output pulse of the logic IC 31B, since the diode 32 is in the ON state, it has no relation to the time constant of the filter circuit, so that it rises without delay.

  Next, FIG. 7 is a diagram for explaining loss reduction at the time of switching on in the case of supplying thinned pulse power whose on-time is adjusted using the on-time adjusting circuit 7 shown in FIG. In FIG. 7, as in FIG. 5, the transition state of the voltage across the switching element 19 </ b> C when the switching elements 19 </ b> A and 19 </ b> D and the switching elements 19 </ b> B and 19 </ b> C are alternately switched is shown. .

  As can be understood from the explanation in FIG. 5, in order to reduce the loss at the time of switching on when supplying the thinned pulse power, the voltage drop applied to the switching element waiting for the on operation is delayed. The off time of the switching element that is off may be lengthened by the amount. That is, the timing at which the switching elements 19A to 19D are turned off may be advanced. As described above, when the off timing of the switching elements 19A to 19D is changed between the supply of the continuous pulse power without the thinning process and the supply of the pulse power with the thinning process, that is, the on time is changed. It can be seen that even when supplying pulsed power that has undergone thinning-out processing, it is possible to reduce the loss at the time of switching on, as in the case of supplying continuous pulse power without performing thinning-out processing.

  The on-time adjusting circuit 7 shown in FIG. 4 is configured to increase the on-time of the switching element that is on, as indicated by reference symbols C and D in FIG. It is possible to secure the off time of the switching element that is off for a time sufficient for the voltage applied to the switching element to drop to 0V. Therefore, when the on-time adjusting circuit 7 shown in FIG. 4 is used, as shown in FIG. 7, the on-time voltage difference between the switching elements 19B and 19C can be almost 0V.

  As described above, according to the first embodiment, the on-time adjusting circuit supplies the on-time of the command pulse group after the thinning process according to the value of the mode selection signal when supplying the continuous pulse power without the thinning process. Since it can be changed depending on the supply of thinned pulse power, even when thinned pulse power is supplied, it is possible to reduce the loss when switching on, as in the case of continuous pulse power supply without thinning processing. Become.

Embodiment 2. FIG.
FIG. 8 is a circuit diagram showing another configuration example (No. 1) of the on-time adjusting circuit shown in FIG. 1 as Embodiment 2 of the present invention. FIG. 8 shows a configuration example in which three types of thinning processing are performed in the thinning circuit 8. That is, the mode selection signal 16 output from the control circuit 9 is a binary data signal indicating four values. For example, if the mode selection signal 16 has a value of 0, it indicates that the thinned-out designated pulse group 17 from the thinning circuit 8 has not been thinned. If the mode selection signal 16 is 1, it indicates that the specified pulse group 17 after thinning-out processing from the thinning-out circuit 8 is performed at intervals of one pulse thinning. If the mode selection signal 16 has a value of 2, it indicates that the specified pulse group 17 after the thinning process from the thinning circuit 8 is performed every two intervals. If the mode selection signal 16 has a value of 3, it is assumed that the designated pulse group 17 after the thinning-out process from the thinning-out circuit 8 is performed every three intervals.

  The selector 30 to which the mode selection signal 16 is input has four output terminals, and the control terminals of the four switches 28A, 28B, 28C, and 28D are connected in a one-to-one relationship.

  One end of each of the four switches 28A, 28B, 28C, 28D is connected to the output terminal of the logic IC 31A to which the command pulse group 17 after the thinning process is input, and the cathode electrode of the diode 32 is connected. One end of each of the four resistors 27A, 27B, 27C, and 27D is connected to the other end of each of the four switches 28A, 28B, 28C, and 28D. The other ends of the four resistors 27A, 27B, 27C, and 27D are commonly connected to one end of a capacitor 29, and the other end of the capacitor 29 is connected to circuit ground.

  An anode terminal of the diode 32 and an input terminal of the logic IC 31B are connected to a connection line between each other end of the four resistors 27A, 27B, 27C, and 27D and one end of the capacitor 29. The switching element on / off signal 18 is output from the output terminal of the logic IC 31 </ b> B to the inverter circuit 5.

  Here, the four resistors 27A, 27B, 27C, and 27D have different resistance values. The series circuit of the resistor 27A and the capacitor 29, the series circuit of the resistor 27B and the capacitor 29, the series circuit of the resistor 27C and the capacitor 29, and the series circuit of the resistor 27D and the capacitor 29 are respectively filters having different time constants. The circuit is configured.

  Although the operation waveform is not shown, the same operation as shown in FIG. 6 is performed in the configuration shown in FIG.

  In the configuration shown in FIG. 8, the logic IC 31A logically inverts the post-thinning designated pulse group 17 from the thinning circuit 8 and applies it to each end of the switches 28A, 28B, 28C, 28D. Further, the logic IC 31B logically inverts a pulse train appearing at the connection end of each of the other ends of the resistors 27A, 27B, 28C, and 28D and one end of the capacitor 29, and outputs it to the inverter circuit 5 as a switching element on / off signal 18. .

  When the mode selection signal 16 has a value of 0, the selector 30 closes the switch 28A and connects the filter circuit including the resistor 27A and the capacitor 29 between the output terminal of the logic IC 31A and the circuit ground. As a result, the falling characteristics of each pulse in the post-decimation command pulse group 17 that has not been thinned out are adjusted by the time constant of the filter circuit composed of the resistor 27A and the capacitor 29.

  Further, when the mode selection signal 16 is 1, the selector 30 closes the switch 28B, and connects the filter circuit including the resistor 27B and the capacitor 29 between the output terminal of the logic IC 31A and the circuit ground. As a result, for example, the falling characteristics of the tooth-missing pulses of the post-decimation command pulse group 17 that are thinned at certain intervals are adjusted by the time constant of the filter circuit composed of the resistor 27B and the capacitor 29. The

  Further, when the mode selection signal 16 is 2, the selector 30 closes the switch 28C and connects the filter circuit including the resistor 27C and the capacitor 29 between the output terminal of the logic IC 31A and the circuit ground. As a result, for example, the falling characteristics of the tooth-missing pulses of the post-thinning-out command pulse group 17 that are thinned out every two intervals are adjusted by the time constant of the filter circuit composed of the resistor 27C and the capacitor 29. The

  Further, when the mode selection signal 16 is 3, the selector 30 closes the switch 28D and connects the filter circuit including the resistor 27D and the capacitor 29 between the output terminal of the logic IC 31A and the circuit ground. As a result, for example, the falling characteristics of the tooth-missing pulses of the post-thinning command pulse group 17 that are thinned at certain intervals are adjusted by the time constant of the filter circuit composed of the resistor 27D and the capacitor 29. The

  The greater the number of thinning out pulses, the longer the time during which discharge stops in the discharge space 13. Therefore, it becomes difficult for the discharge current to flow, the resonance frequency of the load 22 increases, and the voltage drop slows down. Therefore, the larger the number of thinning out, the smaller the time constant of the filter circuit and the shorter the on-time. Therefore, the resistance values of the resistors 27A, 27B, 27C, and 27D become smaller in order of increasing the number of thinning out. Will do.

  According to this configuration, since the state of the discharge space 13 becomes an intermediate state between the case where the laser pulse light is output continuously with the initial state, depending on the number of thinnings, the voltage applied to the switching element to be turned on Even when the time constants of the drop are different, the ON time of each pulse of the command pulse group 17 after the thinning process can be adjusted by the ON time adjusting circuit so as to reduce the loss at the time of switching ON.

Embodiment 3 FIG.
FIG. 9 is a circuit diagram showing another configuration example (No. 2) of the on-time adjusting circuit shown in FIG. 1 as Embodiment 3 of the present invention. As a method for switching the time constant of the filter circuit, the first embodiment (FIG. 4) and the second embodiment (FIG. 8) show the case where the resistance value is switched. In this third embodiment (FIG. 9), The case where the capacitance value is switched is shown.

  FIG. 9 shows a configuration example in the case where three types of thinning processing in the thinning circuit 8 are performed as in the second embodiment. That is, the mode selection signal 16 output from the control circuit 9 is a binary data signal indicating four values.

  One end of the resistor 27 and the cathode terminal of the diode 32 are connected to the output terminal of the logic IC 31A to which the command pulse group 17 after the thinning process is input. The other end of the resistor 27 and the anode terminal of the diode 32 are connected in common to the input terminal of the logic IC 31B, and one end of each of the four switches 28A, 28B, 28C, 28D is connected. A switching element on / off signal 18 from the output terminal of the logic IC 31B to the inverter circuit 5 is output.

  One end of each of four capacitors 29A, 29B, 29C, 29D is connected to each other end of the four switches 28A, 28B, 28C, 28D in a one-to-one relationship, and four capacitors 29A, 29B, 29C, 29D are connected. The other end of each is connected to the circuit ground in common. The selector 30 to which the mode selection signal 16 is input has four output terminals, and the control terminals of the four switches 28A, 28B, 28C, and 28D are connected in a one-to-one relationship.

  Here, the four capacitors 29A, 29B, 29C, and 29D have different capacitance values. The series circuit of the resistor 27 and the capacitor 29A, the series circuit of the resistor 27 and the capacitor 29B, the series circuit of the resistor 27 and the capacitor 29C, and the series circuit of the resistor 27 and the capacitor 29D are respectively filters having different time constants. The circuit is configured.

  As in the second embodiment, for example, when the value of the mode selection signal 16 is 0, which is not subjected to thinning processing, the switch 28A is closed to select a filter circuit including the resistor 27 and the capacitor 29A. When the value of the mode selection signal 16 is a value 1 for performing the thinning process for one pulse, the switch 28B is closed to select a filter circuit including the resistor 27 and the capacitor 29B. When the value of the mode selection signal 16 is a value 2 for performing the thinning process for two pulses, the switch 28C is closed to select a filter circuit including the resistor 27 and the capacitor 29C. When the value of the mode selection signal 16 is a value 3 for performing the thinning-out process for 3 pulses, the filter circuit including the resistor 27 and the capacitor 29D can be selected by closing the switch 28D.

  Although the operation waveform is not shown, the same operation as shown in FIG. 6 is performed in the configuration shown in FIG.

  The greater the number of thinning out pulses, the longer the time during which discharge stops in the discharge space 13. Therefore, it becomes difficult for the discharge current to flow, the resonance frequency increases, and the voltage drop slows down. Therefore, the larger the number of thinning out, the smaller the time constant of the filter circuit and the shorter the on-time. Therefore, the capacitance values of the capacitors 29A, 29B, 29C, and 29D are made smaller in order of increasing the number of thinning out. It will follow.

  According to this configuration, as in the second embodiment, the state of the discharge space 13 becomes an intermediate state between the case where the pulse laser beam 14 is output continuously from the initial state, depending on the number of thinning-out. Even if the time constants at which the voltage applied to the switching to be decreased is different, the ON time of each pulse of the command pulse group 17 after the thinning process is adjusted by the ON time adjusting circuit 7 so as to reduce the loss at the time of switching ON. can do.

  As described above, the gas laser power supply device according to the present invention can reduce the loss at the time of switching-on even when supplying pulsed power that has been subjected to thinning processing, as in the case of supplying continuous pulse power without performing thinning processing. It is useful as a power supply device.

It is a block diagram which shows the structure of the power supply device for gas lasers by Embodiment 1 of this invention. It is a figure explaining the structural example of the inverter circuit shown in FIG. 1, and its load. It is a figure explaining time constant adjustment in the case of supplying the continuous pulse electric power which does not perform a thinning process. FIG. 2 is a circuit diagram illustrating a configuration example of an on-time adjusting circuit illustrated in FIG. 1. It is a figure explaining the loss at the time of switching ON in the case of supplying the pulse electric power which carried out the thinning process without adjusting ON time. FIG. 5 is a diagram for explaining an operation in which the on-time of the command pulse group after the thinning process is changed by the on-time adjusting circuit shown in FIG. 4. FIG. 5 is a diagram for explaining loss reduction at the time of switching on in the case of supplying thinned pulse power whose on-time is adjusted using the on-time adjusting circuit shown in FIG. 4. FIG. 7 is a circuit diagram showing another configuration example (No. 1) of the on-time adjusting circuit shown in FIG. 1 as Embodiment 2 of the present invention; FIG. 7 is a circuit diagram showing another configuration example (No. 2) of the on-time adjusting circuit shown in FIG. 1 as Embodiment 3 of the present invention;

Explanation of symbols

1 Power supply (gas laser power supply)
2 Gas Laser Oscillator 3 AC Power Supply 4 Inverter Circuit 6 Step-up Transformer 7 On-Time Adjustment Circuit 8 Thinning Circuit 9 Control Circuit 10 Electrode 11 Total Reflection Mirror 12 Partial Reflection Mirror 13 Discharge Space 14 Pulse Laser Light 15 Command Pulse Group 16 Mode Selection Signal 17 Thinning Out Post-processing command pulse group 18 Switching element on / off signal 19A, 19B, 19C, 19D Switching element 20A, 20B, 20C, 20D Floating capacitance element 21A, 21B, 21C, 21D Freewheeling diode 22 Load of inverter circuit 22A Inductance of step-up transformer Component 22B Capacitance component formed between electrodes of gas laser oscillator 22C Resistive component of electrode of gas laser oscillator 27, 27A, 27B, 27C, 27D Resistors 28A, 28B constituting filter circuit 28C, 28D switches 29,29A, 29B, 29C, the capacitor 30 selectors 31A constituting the 29D filter circuit, 31B Logic IC
32 diodes

Claims (4)

A control circuit that outputs a command pulse group and a mode selection signal based on a repetition pulse frequency and a pulse width indicated by a control parameter that defines characteristics of a pulsed laser beam output from a gas laser oscillator;
Depending on the operation mode indicated by the mode selection signal, a process for not decimating pulses from the command pulse group and a process for decimating, and outputting them as a command pulse group after decimation processing,
An on-time adjusting circuit for changing and outputting an on-time of the command pulse group after the thinning process according to an operation mode indicated by the mode selection signal;
A pulse power generation circuit for generating pulse power to be supplied to the gas laser oscillator based on the command pulse group after the thinning process whose on time is adjusted by the on time adjustment circuit;
A gas laser power supply device comprising:   The on-time adjusting circuit includes a filter circuit including a resistor and a capacitor, and a circuit that changes a time constant of the filter circuit in accordance with an operation mode indicated by the mode selection signal. Item 2. The gas laser power supply device according to Item 1.   3. The gas laser power supply device according to claim 2, wherein the circuit that changes the time constant of the filter circuit is a circuit that switches a resistance value of the resistor.   3. The gas laser power supply device according to claim 2, wherein the circuit that changes the time constant of the filter circuit is a circuit that switches a capacitance value of the capacitor.

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