WO2015145742A1 - Laser-diode drive circuit and laser device - Google Patents

Laser-diode drive circuit and laser device Download PDF

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Publication number
WO2015145742A1
WO2015145742A1 PCT/JP2014/059202 JP2014059202W WO2015145742A1 WO 2015145742 A1 WO2015145742 A1 WO 2015145742A1 JP 2014059202 W JP2014059202 W JP 2014059202W WO 2015145742 A1 WO2015145742 A1 WO 2015145742A1
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Prior art keywords
laser diode
laser
circuit
voltage
laser diodes
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PCT/JP2014/059202
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French (fr)
Japanese (ja)
Inventor
隼規 坂本
一郎 福士
章之 門谷
一馬 渡辺
次郎 齊川
直也 石垣
進吾 宇野
廣木　知之
東條　公資
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株式会社島津製作所
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Priority to PCT/JP2014/059202 priority Critical patent/WO2015145742A1/en
Publication of WO2015145742A1 publication Critical patent/WO2015145742A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/40—Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30
    • H01S5/4018—Lasers electrically in series
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
    • H01S5/042—Electrical excitation ; Circuits therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/068—Stabilisation of laser output parameters
    • H01S5/06825—Protecting the laser, e.g. during switch-on/off, detection of malfunctioning or degradation

Definitions

  • the present invention relates to a laser diode drive circuit and a laser device.
  • Laser diodes are known to have a relatively short life among components that constitute laser devices such as optical elements and electronic components. Further, it is known that the lifetime of the laser diode becomes shorter as the operating temperature becomes higher. For this reason, in a laser device using a laser diode, the life of the laser device depends on the life of the laser diode.
  • Patent Document 1 a plurality of laser diodes are connected in parallel to obtain a high-intensity laser beam output.
  • the light receiving means detects that one of the laser diodes has failed, the drive current of the failed laser diode is turned off.
  • the drive current of the laser diode that has not failed is increased, and the output of the entire laser diode is kept constant. This extends the life of the laser device.
  • Patent Document 2 a plurality of laser diodes are connected in series to obtain a high-intensity laser beam output.
  • a laser diode in which a plurality of laser diodes are connected in series for each arbitrary group and disposed at a place where heat dissipation is easy a large output is obtained by increasing the drive current.
  • a small output can be obtained by reducing the drive current, but heat generation is reduced. For this reason, since the nonuniformity of the operating temperature of the plurality of laser diodes can be suppressed, the lifetimes of the laser diodes are averaged, and the lifetime of the laser device is extended.
  • the pumping light source device described in Patent Document 3 includes a pumping light source circuit in which a plurality of laser diodes are connected in series, and each laser diode is connected in parallel with a bypass circuit having a larger voltage drop than the laser diode. And a failure detection circuit that detects a failure of the laser diode based on a change in the voltage drop across the entire excitation light source circuit.
  • Patent Document 1 it is necessary to detect the output by light receiving means such as a photodiode for the output from all the laser diodes. For this reason, the arrangement of the light receiving means increases costs and adjustment labor, and increases the output loss in the light receiving means.
  • Patent Document 2 if the laser diode breaks down quickly due to variations in the life of the laser diode, useless power is supplied to the failed laser diode, and the amount of heat generation increases. Further, due to the heat generated by the failed laser diode, the temperature of other non-failed laser diodes may increase.
  • Patent Document 3 only a failure of the laser diode is detected, and the life of the laser diode cannot be extended.
  • a laser diode driving circuit includes a plurality of laser diodes connected in series, a variable voltage source applied to both ends of the plurality of laser diodes, and the plurality of laser diodes.
  • a plurality of bypass circuits provided corresponding to the laser diodes, connected to both ends of each laser diode, for detecting a failure of the laser diode and bypassing the laser diode; and the laser diodes from the plurality of bypass circuits
  • a power supply voltage control circuit for reducing the voltage value of the variable voltage source in the event of failure.
  • the laser device includes a laser diode drive circuit, a combining unit that combines laser beams output from each of the plurality of laser diodes, and a converging unit that converges the laser beam combined by the combining unit. .
  • the present invention it is possible to provide a laser diode driving circuit and a laser device capable of reducing the cost and reducing unnecessary heat generation and extending the life of the laser diode and the laser device.
  • FIG. 1 is a diagram showing a configuration of a laser apparatus including a laser diode drive circuit according to an embodiment of the present invention.
  • FIG. 2 is a diagram showing details of a short-circuit failure detection circuit and a bypass circuit in the laser diode drive circuit of Example 1 according to the embodiment of the present invention.
  • FIG. 3 is a diagram showing details of a short failure detection circuit, an open failure detection circuit, and a bypass circuit in the laser diode drive circuit according to the second embodiment of the present invention.
  • FIG. 4 is a diagram showing an example in which the laser drive voltage is lowered when the laser diode fails in the laser diode drive circuit according to the embodiment of the present invention.
  • a laser apparatus includes a laser diode drive circuit, and as shown in FIG. 1, lasers output from each of a plurality of laser diodes 11a to 11c connected in series for emitting excitation light.
  • the light is synthesized at the multiplexing unit 18 and irradiated onto the processing target 21 to process the processing target 21.
  • the laser beam synthesized by the multiplexing unit 18 passes through the optical fiber 19, is converged by the converging lens 20 (corresponding to the converging unit of the present invention), and is irradiated onto the workpiece 21.
  • the laser diode drive circuit is configured as follows.
  • the positive electrode of the variable voltage source 10 is connected to the anode of the laser diode 11a via the resistor R1, and the negative electrode of the variable voltage source 10 is grounded.
  • One end of an N-type MOSFET 13 is connected to the cathode of the laser diode 11c, and the other end of the MOSFET 13 is grounded.
  • the MOSFET 13 supplies a constant current to the plurality of laser diodes 11a to 11c.
  • a bypass circuit 12a is connected to both ends of the laser diode 11a. When a failure occurs in the laser diode 11a, the bypass circuit 12a bypasses the current without passing through the laser diode 11a and outputs a first failure detection signal indicating that the failure of the laser diode 11a is detected to the monitor circuit 15 To do.
  • a bypass circuit 12b is connected to both ends of the laser diode 11b. When a failure occurs in the laser diode 11b, the bypass circuit 12b bypasses the current without passing through the laser diode 11b and outputs a second failure detection signal indicating that the failure of the laser diode 11b is detected to the monitor circuit 15 To do.
  • a bypass circuit 12c is connected to both ends of the laser diode 11c.
  • the bypass circuit 12c when a failure occurs in the laser diode 11c, bypasses the current without passing through the laser diode 11c and outputs a third failure detection signal indicating that the failure of the laser diode 11c is detected to the monitor circuit 15 To do.
  • the monitor circuit 15 is connected to the bypass circuits 12a to 12c, monitors the failure detection signals sent from the bypass circuits 12a to 12c, and sends the number of failure detection signals, that is, the number of failed laser diodes to the microcomputer 17. Output.
  • the monitor circuit 15 is an operational amplifier that detects a voltage value generated by a current flowing through the bypass circuit 12.
  • the microcomputer 17 supplies a voltage value corresponding to the number of failed laser diodes sent from the monitor circuit 15, that is, a voltage value obtained by multiplying the forward drop voltage VF of the laser diode by the number of failed laser diodes to the power supply voltage. Output to the control circuit 14.
  • the power supply voltage control circuit 14 lowers the voltage of the variable voltage source 10 by a voltage value obtained by multiplying the forward drop voltage VF of the laser diode sent from the microcomputer 17 by the number of failed laser diodes.
  • the current control circuit 16 controls the constant current of the MOSFET 13 according to the number of failed laser diodes sent from the microcomputer 17.
  • the current control circuit 16 is a circuit that allows a constant current to flow by a method for controlling the magnitude of the base current flowing through the transistor or a method for controlling the magnitude of the gate voltage of the FET.
  • FIG. 2 is a diagram showing details of a short circuit failure detection circuit and a bypass circuit in the laser diode drive circuit of Example 1 according to the embodiment of the present invention.
  • FIG. 2 the configurations of the short-circuit failure detection circuit and the bypass circuit for the laser diode 11a are shown, but the configurations of the short-circuit failure detection circuit and the bypass circuit for the laser diodes 11b and 11c are the same.
  • the anode of the diode 22 is connected to the anode of the laser diode 11 a, and the cathode of the diode 22 is connected to the non-inverting input terminal (+ terminal) of the comparator 23.
  • the cathode of the laser diode 11 a is connected to the inverting input terminal ( ⁇ terminal) of the comparator 23.
  • the diode 22 and the comparator 23 constitute a short failure detection circuit that detects a short (short circuit) failure of the laser diode 11a.
  • the output terminal of the comparator 23 is connected to the gate G of the P-type MOSFET Q1 and the monitor circuit 15.
  • the source S of the MOSFET Q1 is connected to the anode of the laser diode 11a and the anode of the diode 22.
  • the drain D of the MOSFET Q1 is connected to the cathode of the laser diode 11a.
  • the MOSFET Q1 bypasses the current without going through the laser diode 11a when the laser diode 11a fails.
  • a current flows through the path of the variable voltage source 10 ⁇ the resistor R 1 ⁇ the laser diode 11 a ⁇ the laser diode 11 b ⁇ the laser diode 11 c ⁇ the MOSFET 13.
  • the forward drop voltage of the laser diode is 2V and the forward drop voltage of the diode is 0.6V
  • the + terminal voltage of the comparator 23 is about 1.4V larger than the ⁇ terminal voltage
  • the output of the comparator 23 is H level.
  • the MOSFET Q1 in the bypass circuit 12a is turned off, so that no current flows in the bypass circuit 12a.
  • the forward voltage drop of the laser diode 11a is approximately 0V, which is smaller than the forward voltage drop (eg, 0.6V) of the diode 22.
  • the output of the comparator 23 becomes L level and the MOSFET Q1 of the bypass circuit 12a is turned on, so that a current flows through the bypass circuit 12a.
  • the L level output from the comparator 23 is output to the monitor circuit 15 as a short circuit failure detection signal of the laser diode 11 a, and the short circuit failure detection signal is sent to the microcomputer 17. Therefore, the failure of the laser diode 11a can be detected.
  • the second embodiment shown in FIG. 3 is characterized in that an open failure detection circuit 31 is further provided to the first embodiment shown in FIG.
  • the short failure detection circuit 30 is substantially the same as the configuration shown in FIG. 2 except that the output terminal of the comparator 23 is connected to the AND circuit 34.
  • the open failure detection circuit 31 includes a differential amplifier circuit 32 and a comparator 33.
  • the differential amplifier circuit 32 amplifies the voltage across the laser diode 11 a and outputs the amplified voltage to the inverting input terminal of the comparator 33.
  • the comparator 33 outputs an H level to the AND circuit 34 when the voltage output from the differential amplifier circuit 32 is equal to or higher than the voltage Vset applied to the non-inverting terminal, and the voltage output from the differential amplifier circuit 32 is When the voltage is lower than the voltage Vset, the L level is output to the AND circuit 34.
  • the voltage Vset is set to a voltage at which the comparator 33 becomes H level when the laser diode 11a is short-circuited and the comparator 33 is L level when the laser diode 11a is open-failed.
  • the comparator 33 outputs the L level to the AND circuit 34, so that the MOSFET Q1 is turned on and a current flows through the bypass circuit 12a.
  • the microcomputer 17 can detect that the laser diode 11a has failed.
  • the L level is output from the comparator 23 to the AND circuit 34 as described in the first embodiment, so that the L level is output from the AND circuit 34 to the MOSFET Q1.
  • the MOSFET Q1 is turned on and a current flows through the bypass circuit 12a.
  • the output of the comparator 23 in the short failure detection circuit 30 becomes H level as described above.
  • the comparator 33 since the voltage from the differential amplifier circuit 32 is smaller than the voltage Vset, the comparator 33 outputs the H level to the AND circuit 34. For this reason, the MOSFET Q1 is turned off, and no current flows through the bypass circuit 12a.
  • the bypass circuit 12b bypasses the current without passing through the laser diode 11b, and the monitor circuit 15 detects that the laser diode 11b has failed and outputs it to the microcomputer 17. To do.
  • the microcomputer 17 outputs the forward effect voltage VF of the laser diode 11b to the power supply voltage control circuit 14.
  • the power supply voltage control circuit 14 lowers the voltage of the variable voltage source 10 by the forward effect voltage VF of the laser diode 11b sent from the microcomputer 17.
  • the power supply voltage control circuit 14 reduces the power supply voltage decrease Vdc of the laser diode 11a to 11c when the laser diodes 11a to 11c fail, to be smaller than the forward drop voltage VF of the laser diodes 11a to 11c. It may be set to a value. That is, the reduction amount Vdc of the power supply voltage of the laser diode at the time of failure is set to the minimum value in consideration of the variation in the forward voltage drop VF.
  • variable DCDC converter can be used for the power supply voltage control circuit 14.
  • the voltage value of the variable voltage source 10 is determined by the microcomputer 17 so that the extra voltage applied to the MOSFET 13 is minimized.
  • the variable DCDC converter instead of the variable DCDC converter, one having a different output voltage of the DCDC converter according to the number of failures of the laser diode can be used.
  • the forward voltage drop of the bypass circuits 12a to 12c caused by the current bypassed by the bypass circuits 12a to 12c is smaller than the forward voltage drop (VF, for example, 2V) of the laser diodes 11a to 11c, for example, 10 mV. .
  • the voltage drop across the bypass circuits 12a-12c may be greater than 10 mV.
  • the number of laser diodes is three, but the number of laser diodes may be two or more.
  • variable voltage source 10 applied to both ends of the plurality of laser diodes 11a to 11c connected in series and the plurality of laser diodes 11a to 11c are connected.
  • a plurality of bypass circuits 12a to 12c provided correspondingly and connected to both ends of each of the laser diodes 11a to 11c to detect a failure of the laser diodes 11a to 11c and to bypass the laser diodes 11a to 11c;
  • a power supply voltage control circuit 14 for reducing the voltage value of the variable voltage source 10 according to the number of laser diode failures from the bypass circuits 12a to 12c.
  • the power supply voltage of the variable voltage source 10 is, for example, Vcc
  • the number of failed laser diodes is n
  • the forward drop voltage of the laser diode is VF
  • the power supply voltage is set according to the number n of failed laser diodes, for example: Decrease by Vcc- (n ⁇ VF).
  • the laser diode drive circuit of the present invention is not limited to the laser processing apparatus described above, and can be applied to, for example, a laser illumination apparatus.
  • the present invention is applicable to high-power laser devices such as laser processing devices and laser illumination devices.

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)

Abstract

A laser-diode drive circuit in which a variable voltage source (10) is imparted to both ends of a plurality of laser diodes (11a-11c) which are connected in series. A plurality of bypass circuits (12a-12c) are provided so as to correspond to the plurality of laser diodes (11a-11c), are connected to both ends of each of the laser diodes (11a-11c), detect a fault in the laser diodes (11a-11c), and bypass the laser diodes (11a-11c). A power source and voltage control circuit (14) decreases the voltage value of the voltage source when a fault occurs in the laser diodes (11a-11c) from the plurality of bypass circuits.

Description

レーザダイオードの駆動回路及びレーザ装置Laser diode drive circuit and laser device
　本発明は、レーザダイオードの駆動回路及びレーザ装置に関する。 The present invention relates to a laser diode drive circuit and a laser device.
　レーザダイオードは、光学素子、電子部品等のレーザ装置を構成する部品の中で比較的寿命が短いことが知られている。また、レーザダイオードは、動作温度が高くなるにつれて、寿命が短くなることが知られている。このため、レーザダイオードを使用したレーザ装置では、レーザダイオードの寿命にレーザ装置の寿命が左右される。 Laser diodes are known to have a relatively short life among components that constitute laser devices such as optical elements and electronic components. Further, it is known that the lifetime of the laser diode becomes shorter as the operating temperature becomes higher. For this reason, in a laser device using a laser diode, the life of the laser device depends on the life of the laser diode.
　複数のレーザダイオードを並列又は直列に接続することにより、高輝度のレーザビーム出力を得る方法においては、レーザダイオードを長寿命化させる手法が提案されている。 In a method of obtaining a high-luminance laser beam output by connecting a plurality of laser diodes in parallel or in series, a method for extending the life of the laser diode has been proposed.
　特許文献１では、複数のレーザダイオードを並列に接続し、高輝度のレーザビーム出力を得ている。いずれか１つのレーザダイオードが故障したことを受光手段が検知すると、故障したレーザダイオードの駆動電流をオフさせる。また、故障していないレーザダイオードの駆動電流を増やし、レーザダイオード全体の出力を一定に保持している。このため、レーザ装置の寿命が延びる。 In Patent Document 1, a plurality of laser diodes are connected in parallel to obtain a high-intensity laser beam output. When the light receiving means detects that one of the laser diodes has failed, the drive current of the failed laser diode is turned off. In addition, the drive current of the laser diode that has not failed is increased, and the output of the entire laser diode is kept constant. This extends the life of the laser device.
　特許文献２では、複数のレーザダイオードを直列に接続し、高輝度のレーザビーム出力を得ている。複数のレーザダイオードを任意のグループごとに直列に接続し、放熱がしやすい場所に配置されたレーザダイオードにおいては、駆動電流を大きくすることで大きな出力を得る。一方、放熱しにくい場所に配置されたレーザダイオードにおいては、駆動電流を小さくすることで小さい出力が得られるが、発熱が小さくなる。このため、複数のレーザダイオードの動作温度のムラが抑えられるため、レーザダイオードの寿命が平均化され、レーザ装置の寿命が延びる。 In Patent Document 2, a plurality of laser diodes are connected in series to obtain a high-intensity laser beam output. In a laser diode in which a plurality of laser diodes are connected in series for each arbitrary group and disposed at a place where heat dissipation is easy, a large output is obtained by increasing the drive current. On the other hand, in a laser diode arranged in a place where it is difficult to dissipate heat, a small output can be obtained by reducing the drive current, but heat generation is reduced. For this reason, since the nonuniformity of the operating temperature of the plurality of laser diodes can be suppressed, the lifetimes of the laser diodes are averaged, and the lifetime of the laser device is extended.
　特許文献３に記載された励起光源装置は、複数のレーザダイオードが直列に接続されると共に、それぞれのレーザダイオードが、レーザダイオードよりも降下電圧が大きいバイパス回路と並列に接続されている励起光源回路と、励起光源回路全体での降下電圧の変化に基づいてレーザダイオードの故障を検出する故障検出回路とを備えている。 The pumping light source device described in Patent Document 3 includes a pumping light source circuit in which a plurality of laser diodes are connected in series, and each laser diode is connected in parallel with a bypass circuit having a larger voltage drop than the laser diode. And a failure detection circuit that detects a failure of the laser diode based on a change in the voltage drop across the entire excitation light source circuit.
特開２００４－２１４２２５号公報JP 2004-214225 A 特開２０１３－８９５０号公報JP 2013-8950 A 特開２０１１－１９９０７９号公報JP 2011-199079 A
　しかしながら、特許文献１では、全てのレーザダイオードからの出力に対して、フォトダイオードなどの受光手段により出力を検知する必要がある。このため、受光手段を配置することによりコスト、調整手間が増加し、また、受光手段における出力損失が大きくなる。 However, in Patent Document 1, it is necessary to detect the output by light receiving means such as a photodiode for the output from all the laser diodes. For this reason, the arrangement of the light receiving means increases costs and adjustment labor, and increases the output loss in the light receiving means.
　また、特許文献２では、レーザダイオードの寿命バラツキにより、レーザダイオードが早く故障してしまった場合には、故障したレーザダイオードに無駄な電力を投入することになり、発熱量が増加してしまう。また、故障したレーザダイオードの発熱により、他の故障していないレーザダイオードの温度が上昇するおそれがあった。 Also, in Patent Document 2, if the laser diode breaks down quickly due to variations in the life of the laser diode, useless power is supplied to the failed laser diode, and the amount of heat generation increases. Further, due to the heat generated by the failed laser diode, the temperature of other non-failed laser diodes may increase.
　また、特許文献３では、レーザダイオードの故障を検出するのみであり、レーザダイオードの長寿命化を図ることはできなかった。 In Patent Document 3, only a failure of the laser diode is detected, and the life of the laser diode cannot be extended.
　本発明は、コストを低減し且つ無駄な発熱を減らしてレーザダイオード及びレーザ装置の長寿命化を図ることができるレーザダイオードの駆動回路及びレーザ装置を提供することを目的とする。 It is an object of the present invention to provide a laser diode drive circuit and a laser device that can reduce the cost and reduce unnecessary heat generation to extend the life of the laser diode and the laser device.
　上記の課題を解決するために、本発明に係るレーザダイオードの駆動回路は、直列に接続された複数のレーザダイオードと、前記複数のレーザダイオードの両端に印加される可変電圧源と、前記複数のレーザダイオードに対応して設けられ、各々のレーザダイオードの両端に接続され、前記レーザダイオードの故障を検出するとともに前記レーザダイオードをバイパスさせる複数のバイパス回路と、前記複数のバイパス回路からの前記レーザダイオードの故障時に前記可変電圧源の電圧値を低下させる電源電圧制御回路とを備える。 In order to solve the above problems, a laser diode driving circuit according to the present invention includes a plurality of laser diodes connected in series, a variable voltage source applied to both ends of the plurality of laser diodes, and the plurality of laser diodes. A plurality of bypass circuits provided corresponding to the laser diodes, connected to both ends of each laser diode, for detecting a failure of the laser diode and bypassing the laser diode; and the laser diodes from the plurality of bypass circuits And a power supply voltage control circuit for reducing the voltage value of the variable voltage source in the event of failure.
　レーザ装置は、レーザダイオードの駆動回路と、前記複数のレーザダイオードの各々から出力されるレーザ光を合成する合波部と、前記合波部で合成されたレーザ光を収束する収束部とを備える。 The laser device includes a laser diode drive circuit, a combining unit that combines laser beams output from each of the plurality of laser diodes, and a converging unit that converges the laser beam combined by the combining unit. .
　本発明によれば、コストを低減し且つ無駄な発熱を減らしてレーザダイオード及びレーザ装置の長寿命化を図ることができるレーザダイオードの駆動回路及びレーザ装置を提供することができる。 According to the present invention, it is possible to provide a laser diode driving circuit and a laser device capable of reducing the cost and reducing unnecessary heat generation and extending the life of the laser diode and the laser device.
図１は本発明の実施形態に係るレーザダイオードの駆動回路を含むレーザ装置の構成を示す図である。FIG. 1 is a diagram showing a configuration of a laser apparatus including a laser diode drive circuit according to an embodiment of the present invention. 図２は本発明の実施形態に係る実施例１のレーザダイオードの駆動回路内のショート故障検知回路及びバイパス回路の詳細を示す図である。FIG. 2 is a diagram showing details of a short-circuit failure detection circuit and a bypass circuit in the laser diode drive circuit of Example 1 according to the embodiment of the present invention. 図３は本発明の実施形態に係る実施例２のレーザダイオードの駆動回路内のショート故障検知回路、オープン故障検知回路及びバイパス回路の詳細を示す図である。FIG. 3 is a diagram showing details of a short failure detection circuit, an open failure detection circuit, and a bypass circuit in the laser diode drive circuit according to the second embodiment of the present invention. 図４は本発明の実施形態に係るレーザダイオードの駆動回路においてレーザダイオードが故障したときにレーザ駆動電圧を下げる例を示す図である。FIG. 4 is a diagram showing an example in which the laser drive voltage is lowered when the laser diode fails in the laser diode drive circuit according to the embodiment of the present invention.
　以下、本発明の実施形態に係るレーザダイオードの駆動回路及びレーザ装置が、レーザ加工装置に適用される場合について、図面を参照しながら詳細に説明される。 Hereinafter, a case where a laser diode drive circuit and a laser apparatus according to an embodiment of the present invention are applied to a laser processing apparatus will be described in detail with reference to the drawings.
　本発明の実施形態に係るレーザ装置は、レーザダイオードの駆動回路を含み、図１に示すように、励起光を出射する直列に接続された複数のレーザダイオード１１ａ～１１ｃの各々から出力されるレーザ光を合波部１８で合成して加工対象物２１に照射し該加工対象物２１を加工する。合波部１８で合成されたレーザ光は、光ファイバ１９を通り、収束レンズ２０（本発明の収束部に対応）で収束されて加工対象物２１に照射される。 A laser apparatus according to an embodiment of the present invention includes a laser diode drive circuit, and as shown in FIG. 1, lasers output from each of a plurality of laser diodes 11a to 11c connected in series for emitting excitation light. The light is synthesized at the multiplexing unit 18 and irradiated onto the processing target 21 to process the processing target 21. The laser beam synthesized by the multiplexing unit 18 passes through the optical fiber 19, is converged by the converging lens 20 (corresponding to the converging unit of the present invention), and is irradiated onto the workpiece 21.
　レーザダイオードの駆動回路は、以下のように構成される。レーザダイオード１１ａのアノードには抵抗Ｒ１を介して可変電圧源１０の正極が接続され、可変電圧源１０の負極は接地されている。 The laser diode drive circuit is configured as follows. The positive electrode of the variable voltage source 10 is connected to the anode of the laser diode 11a via the resistor R1, and the negative electrode of the variable voltage source 10 is grounded.
　レーザダイオード１１ｃのカソードにはＮ型のＭＯＳＦＥＴ１３の一端が接続され、ＭＯＳＦＥＴ１３の他端は接地されている。ＭＯＳＦＥＴ１３は、複数のレーザダイオード１１ａ～１１ｃに定電流を流す。 One end of an N-type MOSFET 13 is connected to the cathode of the laser diode 11c, and the other end of the MOSFET 13 is grounded. The MOSFET 13 supplies a constant current to the plurality of laser diodes 11a to 11c.
　レーザダイオード１１ａの両端にはバイパス回路１２ａが接続されている。バイパス回路１２ａは、レーザダイオード１１ａに故障が発生したときに、レーザダイオード１１ａを介さずに電流をバイパスさせ且つレーザダイオード１１ａの故障を検知したことを示す第１故障検知信号をモニタ回路１５に出力する。 A bypass circuit 12a is connected to both ends of the laser diode 11a. When a failure occurs in the laser diode 11a, the bypass circuit 12a bypasses the current without passing through the laser diode 11a and outputs a first failure detection signal indicating that the failure of the laser diode 11a is detected to the monitor circuit 15 To do.
　レーザダイオード１１ｂの両端にはバイパス回路１２ｂが接続されている。バイパス回路１２ｂは、レーザダイオード１１ｂに故障が発生したときに、レーザダイオード１１ｂを介さずに電流をバイパスさせ且つレーザダイオード１１ｂの故障を検知したことを示す第２故障検知信号をモニタ回路１５に出力する。 A bypass circuit 12b is connected to both ends of the laser diode 11b. When a failure occurs in the laser diode 11b, the bypass circuit 12b bypasses the current without passing through the laser diode 11b and outputs a second failure detection signal indicating that the failure of the laser diode 11b is detected to the monitor circuit 15 To do.
　レーザダイオード１１ｃの両端にはバイパス回路１２ｃが接続されている。バイパス回路１２ｃは、レーザダイオード１１ｃに故障が発生したときに、レーザダイオード１１ｃを介さずに電流をバイパスさせ且つレーザダイオード１１ｃの故障を検知したことを示す第３故障検知信号をモニタ回路１５に出力する。 A bypass circuit 12c is connected to both ends of the laser diode 11c. The bypass circuit 12c, when a failure occurs in the laser diode 11c, bypasses the current without passing through the laser diode 11c and outputs a third failure detection signal indicating that the failure of the laser diode 11c is detected to the monitor circuit 15 To do.
　モニタ回路１５は、バイパス回路１２ａ～１２ｃに接続され、バイパス回路１２ａ～１２ｃから送られてくる故障検知信号をモニタし、故障検知信号の数、即ち、故障したレーザダイオードの数をマイクロコンピュータ１７に出力する。モニタ回路１５は、バイパス回路１２に流れる電流により発生する電圧値を検出するオペアンプなどである。 The monitor circuit 15 is connected to the bypass circuits 12a to 12c, monitors the failure detection signals sent from the bypass circuits 12a to 12c, and sends the number of failure detection signals, that is, the number of failed laser diodes to the microcomputer 17. Output. The monitor circuit 15 is an operational amplifier that detects a voltage value generated by a current flowing through the bypass circuit 12.
　マイクロコンピュータ１７は、モニタ回路１５から送られてくる故障したレーザダイオードの数に対応する電圧値、即ちレーザダイオードの順方向降下電圧ＶＦに、故障したレーザダイオードの数を乗じた電圧値を電源電圧制御回路１４に出力する。電源電圧制御回路１４は、マイクロコンピュータ１７から送られてくるレーザダイオードの順方向降下電圧ＶＦに、故障したレーザダイオードの数を乗じた電圧値だけ可変電圧源１０の電圧を下げる。 The microcomputer 17 supplies a voltage value corresponding to the number of failed laser diodes sent from the monitor circuit 15, that is, a voltage value obtained by multiplying the forward drop voltage VF of the laser diode by the number of failed laser diodes to the power supply voltage. Output to the control circuit 14. The power supply voltage control circuit 14 lowers the voltage of the variable voltage source 10 by a voltage value obtained by multiplying the forward drop voltage VF of the laser diode sent from the microcomputer 17 by the number of failed laser diodes.
　電流制御回路１６は、マイクロコンピュータ１７から送られてくる故障したレーザダイオードの数に応じて、ＭＯＳＦＥＴ１３の定電流を制御する。電流制御回路１６は、トランジスタに流すベース電流の大小を制御する方式や、ＦＥＴのゲート電圧の大小を制御する方式により、一定電流を流す回路である。 The current control circuit 16 controls the constant current of the MOSFET 13 according to the number of failed laser diodes sent from the microcomputer 17. The current control circuit 16 is a circuit that allows a constant current to flow by a method for controlling the magnitude of the base current flowing through the transistor or a method for controlling the magnitude of the gate voltage of the FET.
　図２は本発明の実施形態に係る実施例１のレーザダイオードの駆動回路内のショート故障検知回路及びバイパス回路の詳細を示す図である。図２では、レーザダイオード１１ａについてのショート故障検知回路及びバイパス回路の構成を示したが、レーザダイオード１１ｂ，１１ｃについてのショート故障検知回路及びバイパス回路の構成も同様である。 FIG. 2 is a diagram showing details of a short circuit failure detection circuit and a bypass circuit in the laser diode drive circuit of Example 1 according to the embodiment of the present invention. In FIG. 2, the configurations of the short-circuit failure detection circuit and the bypass circuit for the laser diode 11a are shown, but the configurations of the short-circuit failure detection circuit and the bypass circuit for the laser diodes 11b and 11c are the same.
　レーザダイオード１１ａのアノードには、ダイオード２２のアノードが接続され、ダイオード２２のカソードはコンパレータ２３の非反転入力端子（＋端子）に接続されている。レーザダイオード１１ａのカソードは、コンパレータ２３の反転入力端子（－端子）に接続されている。ダイオード２２とコンパレータ２３とでレーザダイオード１１ａのショート（短絡）故障を検出するショート故障検知回路を構成する。 The anode of the diode 22 is connected to the anode of the laser diode 11 a, and the cathode of the diode 22 is connected to the non-inverting input terminal (+ terminal) of the comparator 23. The cathode of the laser diode 11 a is connected to the inverting input terminal (− terminal) of the comparator 23. The diode 22 and the comparator 23 constitute a short failure detection circuit that detects a short (short circuit) failure of the laser diode 11a.
　コンパレータ２３の出力端子は、Ｐ型のＭＯＳＦＥＴＱ１のゲートＧとモニタ回路１５とに接続されている。ＭＯＳＦＥＴＱ１のソースＳは、レーザダイオード１１ａのアノードとダイオード２２のアノードとに接続されている。ＭＯＳＦＥＴＱ１のドレインＤは、レーザダイオード１１ａのカソードに接続されている。ＭＯＳＦＥＴＱ１は、レーザダイオード１１ａが故障したときにレーザダイオード１１ａを介さずに電流をパイバスさせる。 The output terminal of the comparator 23 is connected to the gate G of the P-type MOSFET Q1 and the monitor circuit 15. The source S of the MOSFET Q1 is connected to the anode of the laser diode 11a and the anode of the diode 22. The drain D of the MOSFET Q1 is connected to the cathode of the laser diode 11a. The MOSFET Q1 bypasses the current without going through the laser diode 11a when the laser diode 11a fails.
　次に、このように構成される実施形態の実施例１のレーザダイオードの駆動回路の動作を図２を参照しながら詳細に説明する。 Next, the operation of the laser diode drive circuit of Example 1 of the embodiment configured as described above will be described in detail with reference to FIG.
　まず、通常の状態では、可変電圧源１０→抵抗Ｒ１→レーザダイオード１１ａ→レーザダイオード１１ｂ→レーザダイオード１１ｃ→ＭＯＳＦＥＴ１３の経路で電流が流れる。レーザダイオードの順方向降下電圧を２Ｖ、ダイオードの順方向降下電圧を０．６Ｖとすると、コンパレータ２３の＋端子電圧は－端子電圧よりも約１．４Ｖ大きくなり、コンパレータ２３の出力はＨレベルとなる。このとき、バイパス回路１２ａ内のＭＯＳＦＥＴＱ１はオフとなるため、バイパス回路１２ａには電流は流れない。 First, in a normal state, a current flows through the path of the variable voltage source 10 → the resistor R 1 → the laser diode 11 a → the laser diode 11 b → the laser diode 11 c → the MOSFET 13. If the forward drop voltage of the laser diode is 2V and the forward drop voltage of the diode is 0.6V, the + terminal voltage of the comparator 23 is about 1.4V larger than the − terminal voltage, and the output of the comparator 23 is H level. Become. At this time, the MOSFET Q1 in the bypass circuit 12a is turned off, so that no current flows in the bypass circuit 12a.
　一方、レーザダイオード１１ａがショート故障した場合には、レーザダイオード１１ａの順方向降下電圧が略０Ｖとなり、ダイオード２２の順方向降下電圧（例えば０．６Ｖ）よりも小さくなる。このとき、コンパレータ２３の出力はＬレベルとなり、バイパス回路１２ａのＭＯＳＦＥＴＱ１はオンするので、バイパス回路１２ａに電流が流れる。 On the other hand, when the laser diode 11a is short-circuited, the forward voltage drop of the laser diode 11a is approximately 0V, which is smaller than the forward voltage drop (eg, 0.6V) of the diode 22. At this time, the output of the comparator 23 becomes L level and the MOSFET Q1 of the bypass circuit 12a is turned on, so that a current flows through the bypass circuit 12a.
　また、コンパレータ２３から出力されるＬレベルは、レーザダイオード１１ａのショート故障検知信号としてモニタ回路１５に出力され、ショート故障検知信号はマイクロコンピュータ１７に送られる。従って、レーザダイオード１１ａの故障を検知することができる。　 Further, the L level output from the comparator 23 is output to the monitor circuit 15 as a short circuit failure detection signal of the laser diode 11 a, and the short circuit failure detection signal is sent to the microcomputer 17. Therefore, the failure of the laser diode 11a can be detected. *
　次に、図３を参照しながら、実施例２のレーザダイオードの駆動回路内のショート故障検知回路、オープン故障検知回路及びバイパス回路の構成を説明する。図３に示す実施例２では、図２に示す実施例１に対して、さらに、オープン故障検知回路３１を備えたことを特徴とする。ショート故障検知回路３０は、図２に示す構成と略同じであるが、コンパレータ２３の出力端子がアンド回路３４に接続されている点が異なる。 Next, the configuration of the short failure detection circuit, the open failure detection circuit, and the bypass circuit in the laser diode drive circuit of Example 2 will be described with reference to FIG. The second embodiment shown in FIG. 3 is characterized in that an open failure detection circuit 31 is further provided to the first embodiment shown in FIG. The short failure detection circuit 30 is substantially the same as the configuration shown in FIG. 2 except that the output terminal of the comparator 23 is connected to the AND circuit 34.
　オープン故障検知回路３１は、差動増幅回路３２、コンパレータ３３とを備える。差動増幅回路３２は、レーザダイオード１１ａの端子間電圧を増幅してコンパレータ３３の反転入力端子に出力する。 The open failure detection circuit 31 includes a differential amplifier circuit 32 and a comparator 33. The differential amplifier circuit 32 amplifies the voltage across the laser diode 11 a and outputs the amplified voltage to the inverting input terminal of the comparator 33.
　コンパレータ３３は、差動増幅回路３２から出力される電圧が非反転端子に印加される電圧Ｖｓｅｔ以上であるときにＨレベルをアンド回路３４に出力し、差動増幅回路３２から出力される電圧が電圧Ｖｓｅｔ未満であるときにＬレベルをアンド回路３４に出力する。電圧Ｖｓｅｔは、レーザダイオード１１ａがショート故障した時に、コンパレータ３３がＨレベルとなり、且つレーザダイオード１１ａがオープン故障した時に、コンパレータ３３がＬレベルとなる電圧に設定される。 The comparator 33 outputs an H level to the AND circuit 34 when the voltage output from the differential amplifier circuit 32 is equal to or higher than the voltage Vset applied to the non-inverting terminal, and the voltage output from the differential amplifier circuit 32 is When the voltage is lower than the voltage Vset, the L level is output to the AND circuit 34. The voltage Vset is set to a voltage at which the comparator 33 becomes H level when the laser diode 11a is short-circuited and the comparator 33 is L level when the laser diode 11a is open-failed.
　次に、図３に示すショート故障検知回路、オープン故障検知回路及びバイパス回路の動作を説明する。 Next, the operation of the short failure detection circuit, the open failure detection circuit, and the bypass circuit shown in FIG. 3 will be described.
　まず、レーザダイオード１１ａがオープン故障した場合には、レーザダイオード１１ａの両端電圧はレーザダイオードの順方向降下電圧よりも大きい電圧となり、差動増幅回路３２からコンパレータ３３の反転入力端子に出力される電圧は、電圧Ｖｓｅｔよりも大きくなる。このため、コンパレータ３３はＬレベルをアンド回路３４に出力するので、ＭＯＳＦＥＴＱ１がオンしてバイパス回路１２ａに電流が流れる。 First, when the laser diode 11a has an open failure, the voltage across the laser diode 11a becomes larger than the forward drop voltage of the laser diode, and the voltage output from the differential amplifier circuit 32 to the inverting input terminal of the comparator 33. Becomes larger than the voltage Vset. Therefore, the comparator 33 outputs the L level to the AND circuit 34, so that the MOSFET Q1 is turned on and a current flows through the bypass circuit 12a.
　また、アンド回路３４からのＬレベルがオープン故障検知信号としてモニタ回路１５に出力されるので、マイクロコンピュータ１７はレーザダイオード１１ａがオープン故障したことを検知することができる。 Since the L level from the AND circuit 34 is output to the monitor circuit 15 as an open failure detection signal, the microcomputer 17 can detect that the laser diode 11a has failed.
　また、レーザダイオード１１ａがショート故障した場合には、実施例１で説明したように、コンパレータ２３からＬレベルがアンド回路３４に出力されるので、アンド回路３４からＬレベルがＭＯＳＦＥＴＱ１に出力されて、ＭＯＳＦＥＴＱ１がオンしてバイパス回路１２ａに電流が流れる。 Further, when the laser diode 11a is short-circuited, the L level is output from the comparator 23 to the AND circuit 34 as described in the first embodiment, so that the L level is output from the AND circuit 34 to the MOSFET Q1. The MOSFET Q1 is turned on and a current flows through the bypass circuit 12a.
　なお、レーザダイオード１１ａが故障していない場合には、ショート故障検知回路３０内のコンパレータ２３の出力は、前述したようにＨレベルとなる。一方、差動増幅回路３２からの電圧は、電圧Ｖｓｅｔよりも小さいので、コンパレータ３３は、Ｈレベルをアンド回路３４に出力する。このため、ＭＯＳＦＥＴＱ１はオフとなり、バイパス回路１２ａには電流は流れない。 If the laser diode 11a is not broken, the output of the comparator 23 in the short failure detection circuit 30 becomes H level as described above. On the other hand, since the voltage from the differential amplifier circuit 32 is smaller than the voltage Vset, the comparator 33 outputs the H level to the AND circuit 34. For this reason, the MOSFET Q1 is turned off, and no current flows through the bypass circuit 12a.
　次に、図４を参照しながら、レーザダイオードが故障したときにレーザ駆動電圧を下げる具体例を説明する。 Next, a specific example of lowering the laser drive voltage when a laser diode fails will be described with reference to FIG.
　例えば、レーザダイオード１１ｂが故障した場合には、バイパス回路１２ｂがレーザダイオード１１ｂを介さずに電流をバイパスさせ、モニタ回路１５は、レーザダイオード１１ｂが故障したことを検知して、マイクロコンピュータ１７に出力する。 For example, when the laser diode 11b fails, the bypass circuit 12b bypasses the current without passing through the laser diode 11b, and the monitor circuit 15 detects that the laser diode 11b has failed and outputs it to the microcomputer 17. To do.
　マイクロコンピュータ１７は、レーザダイオード１１ｂの順方向効果電圧ＶＦを電源電圧制御回路１４に出力する。電源電圧制御回路１４は、マイクロコンピュータ１７から送られてくるレーザダイオード１１ｂの順方向効果電圧ＶＦだけ、可変電圧源１０の電圧を下げる。 The microcomputer 17 outputs the forward effect voltage VF of the laser diode 11b to the power supply voltage control circuit 14. The power supply voltage control circuit 14 lowers the voltage of the variable voltage source 10 by the forward effect voltage VF of the laser diode 11b sent from the microcomputer 17.
　従って、図４に示すように、レーザダイオード１１ｂが故障した場合、レーザ駆動に用いる電圧源の電圧値を下げることができ、ＭＯＳＦＥＴ１３に印加される電圧が増加しない。この結果、レーザ装置の発熱が減り、レーザ装置の長寿命化を図ることができる。 Therefore, as shown in FIG. 4, when the laser diode 11b fails, the voltage value of the voltage source used for laser driving can be lowered, and the voltage applied to the MOSFET 13 does not increase. As a result, heat generation of the laser device is reduced, and the life of the laser device can be extended.
　また、電源電圧制御回路１４は、図４に示すように、レーザダイオード１１ａ～１１ｃの故障時のレーザダイオードの電源電圧の減少量Ｖｄｃを、レーザダイオード１１ａ～１１ｃの順方向降下電圧ＶＦよりも小さい値に設定しても良い。即ち、故障時のレーザダイオードの電源電圧の減少量Ｖｄｃは、順方向降下電圧ＶＦのバラツキを考慮して最小値にする。 Further, as shown in FIG. 4, the power supply voltage control circuit 14 reduces the power supply voltage decrease Vdc of the laser diode 11a to 11c when the laser diodes 11a to 11c fail, to be smaller than the forward drop voltage VF of the laser diodes 11a to 11c. It may be set to a value. That is, the reduction amount Vdc of the power supply voltage of the laser diode at the time of failure is set to the minimum value in consideration of the variation in the forward voltage drop VF.
　また、電源電圧制御回路１４に例えば、可変ＤＣＤＣコンバータを用いることができる。可変ＤＣＤＣコンバータの設定可能な電圧値が離散的である場合、ＭＯＳＦＥＴ１３に印加される余分な電圧が最も小さくなるように、マイクロコンピュータ１７により可変電圧源１０の電圧値を決定する。あるいは、可変ＤＣＤＣコンバータに代えて、レーザダイオードの故障数に応じて、ＤＣＤＣコンバータの出力電圧が異なるものを使用することもできる。 Further, for example, a variable DCDC converter can be used for the power supply voltage control circuit 14. When the settable voltage value of the variable DCDC converter is discrete, the voltage value of the variable voltage source 10 is determined by the microcomputer 17 so that the extra voltage applied to the MOSFET 13 is minimized. Alternatively, instead of the variable DCDC converter, one having a different output voltage of the DCDC converter according to the number of failures of the laser diode can be used.
　さらに、バイパス回路１２ａ～１２ｃにバイパスされた電流により生ずるバイパス回路１２ａ～１２ｃの順方向降下電圧は、レーザダイオード１１ａ～１１ｃの順方向降下電圧（ＶＦ例えば２Ｖ）に比べて小さく、例えば１０ｍＶとする。バイパス回路１２ａ～１２ｃの電圧降下は１０ｍＶより大きくてよい。 Further, the forward voltage drop of the bypass circuits 12a to 12c caused by the current bypassed by the bypass circuits 12a to 12c is smaller than the forward voltage drop (VF, for example, 2V) of the laser diodes 11a to 11c, for example, 10 mV. . The voltage drop across the bypass circuits 12a-12c may be greater than 10 mV.
　また、実施形態では、レーザダイオードの数は３つとしたが、レーザダイオードは、２つ以上であれば良い。 In the embodiment, the number of laser diodes is three, but the number of laser diodes may be two or more.
　このように実施形態のレーザダイオードの駆動回路及びレーザ装置によれば、直列に接続された複数のレーザダイオード１１ａ～１１ｃの両端に印加される可変電圧源１０と、複数のレーザダイオード１１ａ～１１ｃに対応して設けられ、各々のレーザダイオード１１ａ～１１ｃの両端に接続され、前記レーザダイオード１１ａ～１１ｃの故障を検出するとともにレーザダイオード１１ａ～１１ｃをバイパスさせる複数のバイパス回路１２ａ～１２ｃと、前記複数のバイパス回路１２ａ～１２ｃからのレーザダイオードの故障の数に応じて、前記可変電圧源１０の電圧値を低下させる電源電圧制御回路１４とが備えられる。 As described above, according to the laser diode driving circuit and the laser apparatus of the embodiment, the variable voltage source 10 applied to both ends of the plurality of laser diodes 11a to 11c connected in series and the plurality of laser diodes 11a to 11c are connected. A plurality of bypass circuits 12a to 12c provided correspondingly and connected to both ends of each of the laser diodes 11a to 11c to detect a failure of the laser diodes 11a to 11c and to bypass the laser diodes 11a to 11c; And a power supply voltage control circuit 14 for reducing the voltage value of the variable voltage source 10 according to the number of laser diode failures from the bypass circuits 12a to 12c.
　可変電圧源１０の初期の電源電圧を例えばＶｃｃ、故障したレーザダイオードの数をｎ、レーザダイオードの順方向降下電圧をＶＦとすると、故障したレーザダイオードの数ｎに応じて、電源電圧を例えば、Ｖｃｃ－（ｎ×ＶＦ）だけ下げる。 If the initial power supply voltage of the variable voltage source 10 is, for example, Vcc, the number of failed laser diodes is n, and the forward drop voltage of the laser diode is VF, the power supply voltage is set according to the number n of failed laser diodes, for example: Decrease by Vcc- (n × VF).
　これにより、レーザダイオード故障時のトランジスタなどの電流制御素子に印加される電圧ＶＣＥの増加分をＶＦよりも小さく抑えられ、レーザダイオード故障時の電流制御素子の発熱を抑制することができる。また、レーザダイオードが故障した場合にもレーザ装置の長寿命化を図ることができる。 Thereby, an increase in voltage VCE applied to a current control element such as a transistor at the time of failure of the laser diode can be suppressed to be smaller than VF, and heat generation of the current control element at the time of laser diode failure can be suppressed. Further, the life of the laser device can be extended even when the laser diode fails.
　また、受光手段素子を設けないので、コストを低減できる。また、故障したレーザダイオードに流れる電流をバイパスさせることで、無駄な発熱を減らし、他のレーザダイオードの寿命を長くすることができる。 Also, since no light receiving element is provided, the cost can be reduced. Further, by bypassing the current flowing through the failed laser diode, useless heat generation can be reduced and the life of other laser diodes can be extended.
　なお、本発明のレーザダイオードの駆動回路は、前記したレーザ加工装置へ適用されるのに留まらず、例えば、レーザ照明装置への適用も可能である。 The laser diode drive circuit of the present invention is not limited to the laser processing apparatus described above, and can be applied to, for example, a laser illumination apparatus.
　本発明は、レーザ加工装置、レーザ照明装置等の高出力レーザ装置に適用可能である。 The present invention is applicable to high-power laser devices such as laser processing devices and laser illumination devices.

Claims (4)

  1. 　直列に接続された複数のレーザダイオードと、
    　前記複数のレーザダイオードの両端に印加される可変電圧源と、
    　前記複数のレーザダイオードに対応して設けられ、各々のレーザダイオードの両端に接続され、前記レーザダイオードの故障を検出するとともに前記レーザダイオードをバイパスさせる複数のバイパス回路と、
    　前記複数のバイパス回路からの前記レーザダイオードの故障時に前記可変電圧源の電圧値を低下させる電源電圧制御回路と、
    を備えるレーザダイオードの駆動回路。     A plurality of laser diodes connected in series;
    A variable voltage source applied across the plurality of laser diodes;
    A plurality of bypass circuits provided corresponding to the plurality of laser diodes, connected to both ends of each laser diode, and detecting a failure of the laser diode and bypassing the laser diode;
    A power supply voltage control circuit for lowering the voltage value of the variable voltage source when the laser diode fails from the plurality of bypass circuits;
    A laser diode drive circuit comprising:
  2. 　前記電源電圧制御回路は、前記複数のバイパス回路からの前記レーザダイオードの故障の数に前記レーザダイオードの順方向降下電圧を乗算した値に基づき前記電圧源の電圧値を低下させる請求項１記載のレーザダイオードの駆動回路。 The power supply voltage control circuit reduces the voltage value of the voltage source based on a value obtained by multiplying the number of failures of the laser diode from the plurality of bypass circuits by a forward drop voltage of the laser diode. Laser diode drive circuit.
  3. 　前記電源電圧制御回路は、前記レーザダイオードの故障時のレーザダイオードの電源電圧の減少量は、前記レーザダイオードの順方向降下電圧よりも小さい請求項１又は２記載のレーザダイオードの駆動回路。 3. The laser diode drive circuit according to claim 1, wherein the power supply voltage control circuit is configured such that a reduction amount of the power supply voltage of the laser diode when the laser diode fails is smaller than a forward drop voltage of the laser diode.
  4. 　請求項１乃至３のいずれか１項記載のレーザダイオードの駆動回路と、
    　前記複数のレーザダイオードの各々から出力されるレーザ光を合成する合波部と、
    　前記合波部で合成されたレーザ光を収束する収束部と、
    を備えるレーザ加工装置。     A laser diode drive circuit according to any one of claims 1 to 3,
    A multiplexing unit that combines laser beams output from each of the plurality of laser diodes;
    A converging unit for converging the laser beam synthesized in the multiplexing unit;
    A laser processing apparatus comprising:
PCT/JP2014/059202 2014-03-28 2014-03-28 Laser-diode drive circuit and laser device WO2015145742A1 (en)

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