Direct diode laser device

Abstract

To provide a direct diode laser device capable of obtaining satisfactory processing characteristics with first and second laser beams.SOLUTION: A direct diode laser device 100 includes: a first current source 60 that has at least one first laser diode 31a and supplies a first laser light source 31 that emits a first laser beam with first current; a second current source 70 that has at least one second laser diode 32a and supplies a second laser light source 32 that emits a second laser beam with a second current; and a second current source control unit 90 that is configured to execute laser light emission start control for starting emission of the second laser light from the second laser light source 32 by controlling the second current source 70 after the first current exceeds a given lower threshold.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a direct diode laser device that superimposes first and second laser beams and irradiates the superimposed beams onto a workpiece. [Background technology]

[0002] Patent Document 1 discloses a laser device that includes a first laser light source that is made up of a solid-state laser medium and that emits a first laser beam, and a second laser light source that is made up of a laser diode and that emits a second laser beam, and that superimposes the first and second laser beams and irradiates the superimposed beams onto a workpiece. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-217150 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when both the first and second laser light sources are configured with laser diodes, if the second laser light source starts emitting the second laser light before the first laser light source starts emitting the first laser light, good processing characteristics may not be obtained with the first and second laser light.

[0005] The present disclosure has been made in view of the above points, and an object thereof is to obtain good processing characteristics using the first and second laser beams. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a first embodiment of the present disclosure is a direct diode laser device that superimposes first and second laser beams and irradiates the superimposed laser beams onto a workpiece, characterized in that it comprises: a first current source having at least one first laser diode and supplying a first current to a first laser light source that emits the first laser beam; a second current source having at least one second laser diode and supplying a second current to a second laser light source that emits the second laser beam; and a second current source control unit that performs laser beam emission start control to cause the second laser light source to start emitting the second laser beam by controlling the second current source after the first current exceeds a predetermined lower threshold.

[0007] As a result, the second laser light source starts emitting the second laser light after the first current exceeds a predetermined lower threshold, and therefore, by setting the lower threshold to a current value required for the first laser light source to emit the first laser light, the second laser light source can start emitting the second laser light after the first laser light source starts emitting the first laser light. Therefore, if the second laser light source starts emitting the second laser light before the first laser light source emits the first laser light, good processing characteristics can be obtained even when good processing characteristics cannot be obtained with the first and second laser lights. [Effects of the Invention]

[0008] According to the present disclosure, good processing characteristics can be obtained using the first and second laser beams. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a direct diode laser device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing the configuration of a power supply for a laser processing machine. [Figure 3] FIG. 3 is a circuit diagram of the first current source. [Figure 4] FIG. 4 is a circuit diagram of the first power emission command unit and the second power emission command unit. [Figure 5] FIG. 5 is a circuit diagram of the first conduction control unit. [Figure 6] FIG. 6 is a timing chart showing waveforms of the irradiation signal, the first current, the output of the first laser light source, the second current, and the output of the second laser light source. [Figure 7] FIG. 7 is a table showing state transitions of the first power source irradiation command unit. [Figure 8] FIG. 8 is a table showing state transitions of the second power source irradiation command unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or uses in any way.

[0011] 1 shows the configuration of a direct diode laser apparatus 100 according to an embodiment of the present disclosure. The direct diode laser apparatus 100 is used to perform cutting, welding, and the like on a workpiece W. The direct diode laser apparatus 100 includes a laser head 1, a controller 2, a light-emitting device 3, a laser processing power supply 4, and an optical fiber 9.

[0012] The laser head 1 emits laser light LB that is emitted by the light emitting device 3 and passes through an optical fiber 9 .

[0013] The controller 2 outputs a current command, a supply current mode (standby state, simmer state, main state), and the like in response to a user input.

[0014] The light emitting device 3 includes a first laser light source 31, a second laser light source 32, and a light collecting unit 33.

[0015] As shown in FIGS. 2 and 3, the first laser light source 31 has one or more first laser diodes 31a (only one is shown in FIGS. 2 and 3) connected between the first and second nodes N1 and N2, and emits a first laser beam. The first laser diode 31a is a blue laser diode. The first laser beam is blue. When the first laser light source 31 is configured with a plurality of first laser diodes 31a, the plurality of first laser diodes 31a may form a DDL (direct diode laser).

[0016] As shown in FIGS. 2 and 3, the second laser light source 32 has one or more second laser diodes 32a (only one is shown in FIGS. 2 and 3) and emits second laser light. The second laser diode 32a is a near-infrared laser diode. The second laser light is red and is a near-infrared laser. Furthermore, when the second laser light source 32 is composed of multiple second laser diodes 32a, the multiple second laser diodes 32a may constitute a DDL.

[0017] Since the first laser light is blue, it has a higher absorption rate in copper than the second laser light, which is red. The first and second laser light sources 31 and 32 have different current-to-voltage characteristics. Specifically, when the magnitudes of the currents flowing through the first and second laser light sources 31 and 32 are equal, the voltage of the first laser light source 31 is higher than the voltage of the second laser light source 32. The maximum current that can continuously oscillate the second laser light source 32 is higher than the maximum current that can continuously oscillate the first laser light source 31.

[0018] The focusing unit 33 superimposes the first laser light emitted by the first laser light source 31 and the second laser light emitted by the second laser light source 32 and emits the superimposed laser light to the optical fiber 9. The laser light LB emitted to the optical fiber 9 passes through the optical fiber 9 and is irradiated by the laser head 1 onto a workpiece W as a workpiece. The workpiece W is made of copper.

[0019] As shown in FIG. 2, the power supply 4 for a laser processing machine has a first current source 40, a second current source 50, a first detection unit 60, a second detection unit 70, a first current source control unit 80, and a second current source control unit 90.

[0020] The first current source 40 supplies a first current to the first laser light source 31. Specifically, as shown in FIG. 3, the first current source 40 includes a first rectifier circuit 41, a switching circuit 42, a DC link capacitor 43, and a DC current generating circuit 44.

[0021] The first rectifier circuit 41 converts the power supply voltage output from the AC power supply 200 into a DC voltage and outputs it from a pair of output nodes ON1 and ON2. The first rectifier circuit 41 is formed of, for example, a diode bridge.

[0022] The switching circuit 42 is an inverter circuit that generates a first AC voltage in response to the voltages of the output nodes ON1 and ON2 of the first rectifier circuit 41. Specifically, the switching circuit 42 has a first upper-arm switching element 42a and a first lower-arm switching element 42b connected in series between the pair of output nodes ON1 and ON2 of the first rectifier circuit 41, and a second upper-arm switching element 42c and a second lower-arm switching element 42d connected in series between the pair of output nodes ON1 and ON2 of the first rectifier circuit 41. A freewheeling diode 42e is connected in parallel to each of the switching elements 42a to 42d. The switching circuit 42 generates the first AC voltage using the DC voltage output by the first rectifier circuit 41 through the switching operations of these switching elements 42a to 42d.

[0023] The DC link capacitor 43 is connected between the first rectifier circuit 41 and the switching circuit 42, in parallel with the first rectifier circuit 41 and the switching circuit 42. The DC link capacitor 43 is connected between a pair of output nodes ON1 and ON2 of the first rectifier circuit 41.

[0024] The DC current generating circuit 44 uses the first AC voltage generated by the switching circuit 42 to pass a first DC current through the first laser light source 31. The DC current generating circuit 44 has an isolation transformer 45, a second rectifier circuit 46, and a reactor 47.

[0025] The isolation transformer 45 converts the first AC voltage generated by the switching circuit 42 into a second AC voltage and outputs the second AC voltage. The isolation transformer 45 has a primary coil 45a and a secondary coil 45b. The voltage of the primary coil 45a becomes the first AC voltage, and the voltage of the secondary coil 45b becomes the second AC voltage. The primary coil 45a is connected between the connection point of the first upper arm switching element 42a and the first lower arm switching element 42b and the connection point of the second upper arm switching element 42c and the second lower arm switching element 42d.

[0026] The second rectifier circuit 46 supplies a DC supply current to the first laser diode 31a of the first laser light source 31 based on the second AC voltage output by the isolation transformer 45. Specifically, the second rectifier circuit 46 has first and second rectifier diodes 46a and 46b. The anode of the first rectifier diode 46a is connected to one end of the secondary coil 45b, and the anode of the second rectifier diode 46b is connected to the other end of the secondary coil 45b. The cathodes of the first and second rectifier diodes 46a and 46b are connected to a first node N1.

[0027] The reactor 47 is connected between the middle of the secondary coil 45b and the second node N2.

[0028] The second current source 50 supplies a second current to the second laser light source 32. The second current source 50 has the same circuit configuration as the first current source 40. The first current source 40 and the second current source 50 have different output voltage characteristics with respect to the output current. Specifically, the maximum current that the first current source 40 can supply is smaller than the maximum current that the second current source 50 can supply. Furthermore, the maximum voltage that the first current source 40 can output is higher than the maximum voltage that the second current source 50 can output.

[0029] The first detector 60 detects the current value of the first current supplied to the first laser light source 31 by the first current source 40, and outputs a detection value Im1.

[0030] The second detector 70 detects the current value of the second current supplied to the second laser light source 32 by the second current source 50, and outputs a detection value Im2.

[0031] The first current source control unit 80 controls the switching elements 42a to 42d of the switching circuit 42 of the first current source 40 so as to reduce the absolute value of the difference between the detection value Im1 of the first detection unit 60 and a predetermined first command current Ic1 (see FIG. 5).

[0032] The first current source control unit 80 has a first power source irradiation command unit 81, a first conduction control unit 82, a first drive control unit 83, an upper limit threshold setting unit 84, and a first D / A (Digital-to-Analog) converter 85.

[0033] The first power irradiation command unit 81 receives the irradiation signal SS, the detection value Im2 of the second detection unit 70, and a preset upper limit threshold TH H The first power irradiation command unit 81 outputs a first irradiation-on signal SS1 based on the detected value Im2 of the second detection unit 70 when the irradiation signal SS is at a low level and the detected value Im2 of the second detection unit 70 is equal to or lower than the upper threshold value TH H 4, the first power source irradiation command unit 81 has a first comparator 81a, a NOT gate 81b, a first AND circuit 81c, and first and second diodes 81d and 81e.

[0034] The first comparator 81a detects whether the detection value Im2 of the second detection unit 70 is equal to or lower than the upper threshold value TH H When the detection value Im2 of the second detection unit 70 exceeds the upper threshold value TH H When the voltage drops below 10 V, the output is low.

[0035] The NOT gate 81b inverts the output of the first comparator 81a and outputs the inverted output.

[0036] The first AND circuit 81c outputs a high level when the irradiation signal SS is at a high level and the output of the NOT gate 81b is at a high level, and outputs a low level in other cases.

[0037] The anode of the first diode 81d is connected to the output of the AND circuit 81c.

[0038] The anode of the second diode 81e is connected to the output of the first comparator 81a.

[0039] The cathodes of the first and second diodes 81d and 81e are connected to each other, forming a wired OR. Therefore, if either the output of the AND circuit 81c or the output of the first comparator 81a is high, the cathodes (outputs) of the first and second diodes 81d and 81e are high. Only when both the output of the AND circuit 81c and the output of the first comparator 81a are low, are the cathodes (outputs) of the first and second diodes 81d and 81e low. The voltages of the cathodes (outputs) of the first and second diodes 81d and 81e are output as the first irradiation-on signal SS1.

[0040] 5, the first conduction control unit 82 amplifies the difference between the detection value Im1 of the first detection unit 60 and a predetermined first command current Ic1, and outputs the result as a first control voltage CV1. When the first irradiation-on signal SS1 is at a high level, the first command current Ic1 becomes a command current value that causes the first laser light source 31 to emit laser light, and when the first irradiation-on signal SS1 is at a low level, the first command current Ic1 becomes a simmer current value that does not cause the first laser light source 31 to emit laser light. The first conduction control unit 82 has a differential amplifier 821 and first and second inverting amplifiers 822 and 823.

[0041] The differential amplifier 821 amplifies the difference between the detection value Im1 of the first detector 60 and a predetermined first command current Ic1, and outputs a first amplified signal. The differential amplifier 821 has first to fourth resistors 821a to 821d and a first operational amplifier 821e.

[0042] One end of the first resistor 821a is connected to an input terminal to which the detection value Im1 is input, and the other end of the first resistor 821a is connected to an inverting input terminal of the first operational amplifier 821e.

[0043] One end of the second resistor 821b is connected to the inverting input terminal of the first operational amplifier 821e, and the other end of the second resistor 821b is connected to the output terminal of the first operational amplifier 821e.

[0044] One end of the third resistor 821c is connected to an input terminal to which the first command current Ic1 is input, and the other end of the third resistor 821c is connected to a non-inverting input terminal of the first operational amplifier 821e.

[0045] One end of the fourth resistor 821d is connected to the non-inverting input terminal of the first operational amplifier 821e, and the other end of the fourth resistor 821d is grounded.

[0046] The output of the first operational amplifier 821e is the first amplified signal.

[0047] The first inverting amplifier 822 inverts the polarity of the first amplified signal, amplifies and integrates the signal, and outputs a second amplified signal. The first inverting amplifier 822 includes fifth and sixth resistors 822a and 822b, a capacitor 822c, and a second operational amplifier 822d.

[0048] One end of the fifth resistor 822a is connected to the output of the first operational amplifier 821e, and the other end of the fifth resistor 822a is connected to the inverting input terminal of the second operational amplifier 822d.

[0049] The sixth resistor 822b and the capacitor 822c are connected in series between the inverting input terminal of the second operational amplifier 822d and the output terminal of the second operational amplifier 822d.

[0050] The non-inverting input terminal of the second operational amplifier 822d is grounded, and the output of the second operational amplifier 822d becomes the second amplified signal.

[0051] The second inverting amplifier 823 inverts the polarity of the second amplified signal, amplifies the signal, and outputs the first control voltage CV1. The second inverting amplifier 823 includes seventh and eighth resistors 823a and 823b, and a third operational amplifier 823c.

[0052] One end of the seventh resistor 823a is connected to the output of the second operational amplifier 822d, and the other end of the seventh resistor 823a is connected to the inverting input terminal of the third operational amplifier 823c.

[0053] One end of the eighth resistor 823b is connected to the inverting input terminal of the third operational amplifier 823c, and the other end of the eighth resistor 823b is connected to the output terminal of the third operational amplifier 823c.

[0054] The non-inverting input terminal of the third operational amplifier 823c is grounded, and the output of the third operational amplifier 823c becomes the first control voltage CV1.

[0055] The first drive control unit 83 controls the switching elements 42a to 42d of the switching circuit 42 of the first current source 40 based on the first control voltage CV1 output by the first conduction control unit 82. The first control voltage CV1 corresponds to the duty ratio of the period during which the switching circuit 42 supplies a voltage to the isolation transformer 45.

[0056] The upper limit threshold setting unit 84 receives a user input and sets an upper limit threshold TH according to the input. H In this way, the upper threshold value TH H The upper limit threshold TH stored by the upper limit threshold setting unit 84 is variable. His updated at the start and end of laser irradiation, specifically, when the irradiation signal SS is switched.

[0057] The first D / A converter 85 converts the upper limit threshold TH stored by the upper limit threshold setting unit 84 into a H A voltage according to the voltage is output to the input terminal of the first comparator 81a.

[0058] The second current source control unit 90 controls the switching elements 42a to 42d of the switching circuit 42 of the second current source 50 so as to reduce the absolute value of the difference between the detection value Im2 of the second detection unit 70 and a predetermined second command current.

[0059] The second current source control unit 90 includes a second power source irradiation command unit 91 , a second conduction control unit 92 , a second drive control unit 93 , a lower limit threshold setting unit 94 , and a second D / A converter 95 .

[0060] The second power irradiation command unit 91 receives the irradiation signal SS, the detection value Im1 of the first detection unit 60, and a preset lower limit threshold TH L The second power irradiation command unit 91 outputs a second irradiation-on signal SS2 based on the second power irradiation command when the irradiation signal SS is at a high level and the detection value Im1 of the first detection unit 60 is lower than the lower limit threshold TH L When the detected voltage Vcc exceeds the threshold voltage Vdc, the second irradiation-on signal SS2 is set to a high level. Specifically, as shown in FIG. 4, the second power-supply irradiation command unit 91 has a second comparator 91a and a second AND circuit 91b.

[0061] The second comparator 91a detects whether the detection value Im1 of the first detection unit 60 is lower than the lower threshold TH L When the detection value Im1 of the first detection unit 60 exceeds the lower threshold value TH L When the voltage drops below 10 V, the output is low.

[0062] The second AND circuit 91b outputs a high level as the second irradiation-on signal SS2 when the irradiation signal SS is at a high level and the output of the second comparator 91a is at a high level, and otherwise outputs a low level as the second irradiation-on signal SS2.

[0063] The second conduction control unit 92 amplifies the difference between the detection value Im2 of the second detection unit 70 and a predetermined second command current, and outputs a second control voltage CV2. When the second irradiation-on signal SS2 is at a high level, the second command current has a command current value that causes the second laser light source 32 to emit laser light, and when the second irradiation-on signal SS2 is at a low level, the second command current has a simmer current value that does not cause the second laser light source 32 to emit laser light. The second conduction control unit 92 can be realized with the same circuit configuration as the first conduction control unit 82.

[0064] The second drive control unit 93 controls the switching elements 42a to 42d of the switching circuit 42 of the second current source 50 based on the second control voltage CV2 output by the second conduction control unit 92. The second control voltage CV2 corresponds to the duty ratio of the period during which the switching circuit 42 supplies a voltage to the isolation transformer 45.

[0065] The lower limit threshold setting unit 94 receives a user input and sets a lower limit threshold TH L In this way, the lower threshold value TH L is variable. The lower threshold value TH stored by the lower threshold value setting unit 94 L is updated at the start and end of laser irradiation, specifically, when the irradiation signal SS is switched.

[0066] The second D / A converter 95 converts the lower limit threshold TH stored by the lower limit threshold setting unit 94 into L A voltage according to this is output to the input terminal of the second comparator 91a.

[0067] In the direct diode laser device 100 configured as described above, as shown in Fig. 6, when the irradiation signal SS is at a low level, the first current source 40 supplies a simmer current to the first laser light source 31. The second current source 50 also supplies a simmer current to the second laser light source 32. In Fig. 6, the current value of the simmer current is indicated by the symbol Sm. The current value Sm of the simmer current is a current that does not cause the first laser light source 31 and the second laser light source 32 to emit light.

[0068] From this state, when the irradiation signal SS rises from low level to high level at timing t1, the first irradiation-on signal SS1 goes high. In response to this, the first conduction control unit 82 amplifies the difference between the detection value Im1 of the first detection unit 60 and the first command current Ic1, and outputs a first control voltage CV1 that causes the first laser light source 31 to emit laser light. The first drive control unit 83 controls the switching elements 42a to 42d of the switching circuit 42 of the first current source 40 based on the first control voltage CV1 output by the first conduction control unit 82. By controlling the first current source 40 in this way by the first current source control unit 80, the first current supplied to the first laser light source 31 increases, and the first laser light source 31 starts emitting the first laser light. Then, at timing t2, the detection value Im1 of the first detection unit 60 reaches the lower limit threshold TH L, the second power supply irradiation command unit 91 changes the second irradiation-on signal SS2 from low level to high level. In response to this, the second conduction control unit 92 amplifies the difference between the detection value Im2 of the second detection unit 70 and the second command current, and outputs a second control voltage CV2 that causes the second laser light source 32 to emit laser light. The second drive control unit 93 controls the switching elements 42a to 42d of the switching circuit 42 of the second current source 50 based on the second control voltage CV2 output by the second conduction control unit 92. By controlling the second current source 50 in this way by the second current source control unit 90, the second current supplied to the second laser light source 32 increases, and the second laser light source 32 starts emitting the second laser light. In this way, the second current source control unit 90 controls the second current source 50 to start emitting the second laser light, and the second current source control unit 90 controls the second current source 50 to start emitting the second laser light, when the detection value of the first detection unit 60 reaches a predetermined lower limit threshold TH L Thus, the timing of the laser light emission start control is determined when the first current exceeds a predetermined lower limit threshold TH L Therefore, the lower threshold TH L to a current value required for emission of the first laser light from the first laser light source 31, it is possible to start emission of the second laser light from the second laser light source 32 after emission of the first laser light from the first laser light source 31 has started. In this way, emission of the first laser light, which has a high absorption rate by copper, is started before emission of the second laser light, preventing sole irradiation of the near-infrared laser, thereby increasing the absorption rate of the laser light LB irradiated onto the workpiece W and obtaining good machining characteristics. Furthermore, since the timing of the laser light emission start control is determined with reference to the detection value of the first detection unit 60, so compared to when the timing of the laser light emission start control is set after a predetermined delay time has elapsed since switching of the irradiation signal SS, so it is possible to more reliably prevent sole irradiation of the near-infrared laser and obtain good machining characteristics.

[0069] After that, the first current and the second current finish increasing and become stable. In the stable state after the first current and the second current increase, the first current is smaller than the second current, and the voltage of the first laser light source 31 becomes higher than the voltage of the second laser light source 32.

[0070] After that, at timing t3, when the irradiation signal SS is changed from high level to low level, the second power irradiation command unit 91 changes the second irradiation-on signal SS2 to low level. This reduces the second current supplied to the second laser light source 32, and the output of the second laser light source 32 also decreases. Then, at timing t4, the detection value of the second detection unit 70 reaches a predetermined upper threshold value TH H , the first power supply irradiation command unit 81 changes the first irradiation-on signal SS1 from high to low in response to this. Then, the first conduction control unit 82 outputs a voltage that causes the first current source 40 to output a simmer current as the first control voltage CV1. The first drive control unit 83 controls the switching elements 42a to 42d of the switching circuit 42 of the first current source 40 based on the first control voltage CV1 output by the first conduction control unit 82. By controlling the first current source 40 in this way by the first current source control unit 80, the first current supplied to the first laser light source 31 decreases, and at timing t5, the emission of the first laser light by the first laser light source 31 ends. In this way, the first current source control unit 80 performs the laser light emission termination control that terminates the emission of the first laser light by the first laser light source 31 by controlling the first current source 40, when the detection value of the second detection unit 70 reaches a predetermined upper threshold value TH H Thus, the timing of the laser light emission termination control is determined when the second current falls below a predetermined upper limit threshold TH H Therefore, the upper threshold TH His set to the minimum current value required for the second laser light source 32 to emit the second laser light, it is possible to terminate the emission of the first laser light from the first laser light source 31 after the emission of the second laser light from the second laser light source 32 has terminated. In this way, the emission of the first laser light, which has a high absorption rate by copper, is terminated after the emission of the second laser light, preventing the near-infrared laser from being irradiated alone. This increases the absorption rate of the laser light LB irradiated onto the workpiece W, thereby achieving good machining characteristics. Furthermore, since the timing of the laser light emission termination control is determined with reference to the detection value of the second detection unit 70, it is possible to more reliably prevent the near-infrared laser from being irradiated alone, and achieve good machining characteristics, compared to when the timing of the laser light emission termination control is set to after a predetermined delay time has elapsed since the irradiation signal SS was switched.

[0071] FIG. 7 is a table showing the state transition of the first power source irradiation command unit 81.

[0072] When the first irradiation-on signal SS1 is in an OFF (low level) state, the detection value Im2 of the second detection unit 70 reaches the upper limit threshold TH H If the irradiation signal SS remains in the OFF state for less than 100 seconds, the first power irradiation command unit 81 turns the first irradiation ON signal SS1 OFF (to low level).

[0073] Furthermore, when the first irradiation-on signal SS1 is switched from an off state to an on state (high level) state, the detection value Im2 of the second detection unit 70 becomes equal to or exceeds the upper limit threshold TH H Even if the first power irradiation command unit 81 turns on the first irradiation-on signal SS1 (high level), the first power irradiation command unit 81 turns on the first irradiation-on signal SS1 (high level).

[0074] When the irradiation signal SS is turned off from the state in which the first irradiation-on signal SS1 is on, the detection value Im2 of the second detection unit 70 becomes equal to or lower than the upper threshold value TH H If it is less than this, the first power irradiation command unit 81 turns off the first irradiation-on signal SS1.

[0075] Furthermore, even if the irradiation signal SS is turned off from a state in which the first irradiation-on signal SS1 is on, the detection value Im2 of the second detection unit 70 does not exceed the upper limit threshold TH H If so, the first power irradiation command unit 81 turns on the first irradiation-on signal SS1.

[0076] Furthermore, when the first irradiation-on signal SS1 is in an on state, the detection value Im2 of the second detection unit 70 falls below the upper limit threshold TH H If the irradiation signal SS remains on even if the time is less than the predetermined time, the first power irradiation command unit 81 turns on the first irradiation-on signal SS1.

[0077] Furthermore, when the first irradiation-on signal SS1 is in an on state, the detection value Im2 of the second detection unit 70 falls below the upper limit threshold TH H If the irradiation signal SS remains in the ON state even after this, the first power irradiation command unit 81 turns on the first irradiation ON signal SS1.

[0078] FIG. 8 is a table showing the state transition of the second power source irradiation command unit 91.

[0079] When the second irradiation-on signal SS2 is in an OFF state, the detection value Im1 of the first detection unit 60 is lower than the lower limit threshold TH L If the irradiation signal SS remains in the OFF state even when the time becomes less than the predetermined time, the second power irradiation command unit 91 turns the second irradiation ON signal SS2 OFF (to low level).

[0080] When the second irradiation-on signal SS2 is in an OFF state, the detection value Im1 of the first detection unit 60 is lower than the lower limit threshold TH L Even after the above, if the irradiation signal SS remains in the OFF state, the second power irradiation command unit 91 turns off the second irradiation ON signal SS2.

[0081] Even if the second irradiation-on signal SS2 is turned off and then the irradiation signal SS is turned on, the detection value Im1 of the first detection unit 60 does not exceed the lower limit threshold TH L If it is less than this, the second power irradiation command unit 91 turns off the second irradiation-on signal SS2.

[0082] When the second irradiation-on signal SS2 is turned off, the irradiation signal SS is turned on, and the detection value Im1 of the first detection unit 60 reaches the lower limit threshold TH L If so, the second power irradiation command unit 91 turns on the second irradiation-on signal SS2 (high level).

[0083] When the irradiation signal SS is turned off from a state in which the second irradiation-on signal SS2 is on, the detection value Im1 of the first detection unit 60 falls below the lower limit threshold TH L Even in the above cases, the second power irradiation command unit 91 turns off the second irradiation-on signal SS2.

[0084] When the second irradiation-on signal SS2 is in an on state, the detection value Im1 of the first detection unit 60 falls below the lower limit threshold TH L In the above case, when the irradiation signal SS remains on, the second power irradiation command unit 91 keeps the second irradiation-on signal SS2 on.

[0085] In the above embodiment, the switching circuits 42 of the first current source 40 and the second current source 50 are provided with four switching elements 42a to 42d, but the switching circuits 42 may have any number of switching elements other than four, as long as the number is one or more.

[0086] In the above embodiment, the detection target of the first detector 60 is the current value of the first current supplied to the first laser light source 31, but it may also be the output of the first laser light source 31. The second current source control unit 90 may execute the laser light emission start control in response to the detection value of the first detector 60, i.e., the output of the first laser light source 31, exceeding a predetermined lower threshold. The detection target of the second detector 70 is the current value of the second current supplied to the second laser light source 32, but it may also be the output of the second laser light source 32. The first current source control unit 80 may execute the laser light emission end control in response to the detection value of the second detector 70, i.e., the output of the second laser light source 32, falling below a predetermined upper threshold. [Industrial Applicability]

[0087] The direct diode laser device of the present disclosure can obtain good processing characteristics using the first and second laser beams, and is useful as a direct diode laser device that superimposes the first and second laser beams and irradiates them onto a workpiece. [Explanation of symbols]

[0088] 100 Direct diode laser device 31 First laser light source 31a First laser diode 32 Second laser light source 32a Second laser diode 40 1st current source 50 Second current source 60 First detection unit 70 Second detection unit 80 First current source control section 90 Second current source control section W Work (workpiece) Im1, Im2 detected values TH H Upper Threshold TH L Lower Threshold

Claims

1. A direct diode laser device that irradiates a workpiece with first and second laser beams that are superimposed on each other, a first current source having at least one first laser diode and supplying a first current to a first laser light source that emits the first laser light; a second current source having at least one second laser diode and supplying a second current to a second laser light source that emits the second laser light; a second current source control unit that executes laser light emission start control to cause the second laser light source to start emitting the second laser light by controlling the second current source after the first current exceeds a predetermined lower threshold.

2. 2. The direct diode laser device according to claim 1, a first current source control unit that executes laser light emission termination control to cause the first laser light source to terminate emission of the first laser light by controlling the first current source after the second current falls below a predetermined upper limit threshold.

3. 3. The direct diode laser device according to claim 1, The characteristics of the output voltage with respect to the output current of the first current source and the second current source are different from each other; and A direct diode laser device characterized in that at least one of the first and second laser light sources has different current-to-voltage characteristics.

4. 3. The direct diode laser device according to claim 1, A direct diode laser device, characterized in that a maximum current flowing through the second laser light source is greater than a maximum current flowing through the first laser light source.

5. 3. The direct diode laser device according to claim 1, 10. A direct diode laser device, wherein the first laser beam has a higher absorption rate by copper than the second laser beam.

6. 3. The direct diode laser device according to claim 1, a first detection unit that detects a current value of the first current or an output of the first laser light source; The direct diode laser device is characterized in that the second current source control unit executes the laser light emission start control in response to the detection value of the first detection unit exceeding a predetermined lower limit threshold.

7. 3. The direct diode laser device according to claim 2, a second detection unit that detects a current value of the second current or an output of the second laser light source, The direct diode laser device is characterized in that the first current source control unit executes the laser light emission termination control in response to the detection value of the second detection unit falling below a predetermined upper threshold.

8. 3. The direct diode laser device according to claim 2, The direct diode laser device is characterized in that the lower threshold and the upper threshold are variable.

Images