JP2012204762A - Laser diode unit for laser processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser diode unit for laser processing which can properly cool two laser diodes for the laser processing that are incorporated in a chamber, can maintain high oscillation efficiency of laser light of the laser diodes, and allows the usable environmental temperature to be set to a high temperature.SOLUTION: In a laser diode unit 7, a peltier element 25 is laminated on an upper surface of a bottom plate 17a in a chamber 17 formed into a box shape, and laser diodes 9a, 9b are laminated to be disposed on an upper part of the peltier element 25. Further, a heat sink 27 is attached to a lower surface of the bottom plate 17a. A heat insulation layer 28, blocking heat from being transmitted from the bottom plate 17a of the chamber 17 to areas above the bottom plate 17a, is provided in the laser diode unit 7.

Description

  The present invention relates to a laser diode unit for laser processing.

  In recent years, a laser processing apparatus using a laser diode as a light source of excitation laser light has been proposed (see, for example, Patent Document 1 and FIG. 1).

  In this laser processing apparatus, it will be schematically explained according to the traveling direction of the laser light. First, the excitation laser light is excited by the laser diode for laser processing, and then the excitation laser light is excited to a predetermined wavelength by the oscillation fiber. Next, the laser beam is extracted as a fiber laser beam, and then guided to the processing head by a light guide means such as an optical fiber, and then the processing head is irradiated with the fiber laser beam to perform laser processing. ing.

  In the laser processing apparatus formed in this way, a large output of 20 W or more is used as a light source in order to smoothly and reliably perform processing such as welding and cutting that require large energy on a workpiece such as metal. The laser diode for laser processing formed in the above is used. Furthermore, two laser diodes are used to obtain a higher output, or a laser diode that is heated to oscillate a large energy is formed as a unit independent of the oscillation fiber, and is cooled by air to dissipate heat. ing. The output value of the fiber laser light output from the oscillation fiber is measured by a photo sensor to perform appropriate laser processing while maintaining the output of the fiber laser light at a set value or to detect deterioration of the laser diode. is doing.

JP 2010-010274 A

  Conventionally, two high-power laser diodes are built in a sealable metal box-shaped chamber to form a unit, and the chamber is air-cooled to achieve stable oscillation of laser light by the laser diode. It was like that. Specifically, a Peltier element is installed on the bottom surface in the chamber, a metal plate that serves as a base of the laser diode and the laser diode are sequentially stacked on the Peltier element, and a heat sink is fixed to the lower surface outside the chamber. .

  However, conventionally, heat transferred from the heat radiation surface opposite to the cooling surface on which the laser diodes of the Peltier element are stacked (hereinafter referred to as “hot side”) is thermally connected to the bottom portion. There is a disadvantage that the chamber is heated by being transferred to other components of the chamber. Specifically, heat is transmitted to the side wall of the chamber connected to the bottom portion, and further, the temperature of the chamber may be increased due to heat being transmitted to the lid portion serving as the ceiling portion. If this happens, the temperature inside the unit also rises, and the cooling efficiency of the Peltier element connected to the laser diode may decrease. Therefore, a sufficient cooling effect cannot be obtained, the wavelength of the laser diode changes, and there is a disadvantage that the laser diode cannot be used in a place where the environmental temperature outside the chamber is high.

  The present invention has been made in view of these points, and can properly cool two laser processing laser diodes built in the chamber, and can keep the oscillation wavelength of the laser light of the laser diode constant. It is an object of the present invention to provide a laser diode unit for laser processing that can be maintained at a high temperature and can set a high available ambient temperature.

  In order to achieve the above object, according to one aspect of the laser diode unit for laser processing of the present invention, a Peltier element is stacked on the upper surface of a bottom plate in a chamber formed in a box shape, and the laser diode is formed on the Peltier element. In the laser diode unit, in which a heat sink is attached to the bottom surface of the bottom plate, a heat insulating layer is provided to prevent heat from being transmitted from the bottom plate portion of the chamber to the top. Thus, according to the present invention, the two laser processing laser diodes built in the chamber can be appropriately cooled, and the oscillation wavelength of the laser light oscillated by the laser diode can be maintained constant. The available ambient temperature can be set high.

  In another aspect of the laser diode unit for laser processing according to the present invention, the heat insulating layer is formed over the entire circumference of the side wall continuously provided on the bottom plate of the chamber. Thus, according to the present invention, the heat insulating layer formed over the entire circumference of the side wall can surely prevent heat transfer from the bottom portion of the chamber to the ceiling portion, and more reliably the laser light of the laser diode. The oscillation wavelength can be kept constant.

  Another aspect of the laser diode unit for laser processing according to the present invention is characterized in that the heat insulating layer is formed of a resin material. Thereby, according to this invention, since the heat insulation effect of the heat insulation layer of a resin material is high, the oscillation wavelength of the laser beam of a laser diode can be maintained more reliably.

  The laser diode unit for laser processing of the present invention can appropriately cool two laser processing laser diodes built in the chamber, and can maintain the oscillation wavelength of the laser light of the laser diode constant. It is possible to achieve such an effect that the available ambient temperature can be set high.

The conceptual diagram which shows the laser processing apparatus to which one Embodiment of the laser diode unit for laser processing of this invention is applied The top view which shows one Embodiment of the laser diode unit for laser processing of this invention B feather arrow view of FIG. Sectional view along the AA line of FIG. FIG. 2 is a condensing diagram on the end face of the optical fiber for transmission in FIG. 2 showing the position control state of each laser beam outputted from the two laser diodes.

  The laser diode unit for laser processing according to the present invention will be described below with reference to FIGS.

  FIG. 1 shows a laser processing apparatus 1 having an embodiment of a laser diode unit for laser processing according to the present invention.

  The laser processing apparatus 1 includes a laser oscillation unit 2, a laser incident unit 3, a fiber transmission unit 4, a laser head unit 5, and a processing table 6 in the order of progress of laser light.

  The laser oscillation unit 2 includes a laser diode unit 9 for laser processing that oscillates the laser beam MB, and an optical fiber for oscillation (hereinafter referred to as “oscillation fiber”) 10 as a fiber laser beam FB having a predetermined wavelength. And an oscillator unit 8 for taking out and outputting.

  First, the oscillation of the fiber laser beam FB will be described. In the present embodiment, a pair of optical resonator mirrors 11 and 12 that are optically opposed to each other via the oscillation fiber 10 are arranged in the oscillator unit 8. Optical lenses 13 and 14 are disposed between the optical resonator mirrors 11 and 12 and the end face of the oscillation fiber 10, respectively. One optical lens 13 condenses and enters the laser beam MB output from the laser diode unit 9 side and used for excitation onto one end surface of the oscillation fiber 10. The optical resonator mirror 11 disposed between the laser diode unit 9 and the optical lens 13 transmits the excitation laser beam MB incident from the laser diode unit 9 side, and the oscillation beam incident from the oscillation fiber 10 side. Is totally reflected on the optical axis of the resonator. The oscillating fiber 10 has a core doped with, for example, rare earth ions as a light emitting element, and a clad surrounding the core coaxially. The core is used as an active medium, and the clad is used as a propagation optical path of excitation light. The excitation laser beam MB incident on one end surface of the oscillation fiber 10 as described above propagates in the oscillation fiber 10 in the axial direction while being confined by the total reflection at the outer peripheral interface of the cladding, and the core passes through the propagation during the propagation. By crossing many times, the rare earth element ions in the core are photoexcited. In this way, an oscillating light beam having a predetermined wavelength is emitted in the axial direction from both end faces of the core, and this oscillating light beam travels back and forth between the optical resonator mirrors 11 and 12 and is resonantly amplified. The fiber laser beam FB having the predetermined wavelength is extracted from the resonator mirror 12 and travels in the forward direction. The optical lenses 13 and 14 collimate the oscillating light beam emitted from the end face of the oscillating fiber 10 in parallel and collect the oscillating light beam reflected by the optical resonator mirrors 11 and 12 on the end face of the oscillating fiber 10. Let The excitation laser beam MB that has passed through the oscillation fiber 10 passes through the optical lens 14 and the optical resonator mirror 12 and is then folded back toward the side laser absorber 16 by the folding mirror 15. The fiber laser beam FB output from the optical resonator mirror 12 passes straight through the folding mirror 15 and proceeds to the laser incident portion 3.

  Next, the laser diode unit 9 will be described.

  The laser diode unit 9 is formed as a so-called FC-LD (Fiber Coupling-Laser Diode), and has a structure in which a transmission optical fiber 7 is connected to an output portion of a laser beam MB oscillated in the unit 9. Has been. The end face 7a of the optical fiber 7 serves as an output reference plane from the unit 9 for laser light output from the two laser diodes.

  In the present embodiment, as shown in FIG. 2, a chamber in which two laser diodes 9a and 9b having an output of 20 W or more are formed in a sealable box shape in order to obtain a large output for laser processing. 17 is arranged so that the laser beams MBa and MBb, which are output light beams, are orthogonally output from each other. Both laser diodes 9a and 9b preferably have a multi-emitter structure (not shown) in which a plurality of emitters are arranged in parallel in order to obtain a large output. In the laser diodes 9a and 9b having the multi-emitter structure, the cross sections of the laser beams MBa and MBb to be output are long in one direction. Both laser diodes 9a and 9b are formed so that excitation power is supplied from the laser power source 22 to output laser beams MBa and MBb. Both laser beams MBa and MBb output from both laser diodes 9a and 9b then travel in the forward direction along the optical system shown in FIG. 2, and the reflected light travels in the reverse direction as return light. The reflected light here refers to light reflected by the end face 7a of the transmission optical fiber 7 connected to the laser diode unit 9, and reflected light from optical elements arranged before and after the light. . The laser beams MBa and MBb are merged and output in the same direction at the intersection of the laser beams MBa and MBb output perpendicularly to each other from the laser diodes 9a and 9b, and forward light is output. An optical combiner 18 having a selection output unit 18a that does not output light in the reverse direction is provided. This optical combiner 18 is formed by a polarization beam splitter 19 having an inclined surface 19a inclined at 45 degrees with respect to both laser beams MBa and MBb output perpendicularly to each other. Most of the laser beam MBa composed of laterally polarized light output from one laser diode 9a passes straight through the inclined surface 19a from the back surface side to the front surface side, and a part (for example, 1%) thereof is inclined. The light is reflected from the back surface side of the surface 19a and output from the end surface serving as the selective output unit 18a. Most of the laser beam MBb composed of longitudinally polarized light output from the other laser diode 9b and transmitted through a wave plate 40 described later is reflected on the surface side of the inclined surface 19a, and the inclined surface 19a is reflected on the back surface side. The laser beam MBa transmitted from the laser beam to the surface side is merged and travels in the forward direction, and a part (for example, 1%) passes through the inclined surface 19a from the surface side to the back surface side to become the selective output unit 18a. Output from the end face. A photodiode 20 is installed as a detecting means for detecting the intensity of only the output light of the two laser diodes 9a and 9b so as to face the end face forming the selection output portion 18a of the polarization beam splitter 19. The selective output unit 18a of the polarization beam splitter 19 may be provided with a diffusing unit that diffuses output light from an end face forming the selective output unit 18a. For example, as the diffusing means, the end surface forming the selection output portion 18a may be formed in a ground glass shape (not shown), or a diffusion plate (not shown) may be attached to the end surface forming the selection output portion 18a. As a result, by adopting a multi-emitter structure as both laser diodes 9a and 9b, even if the laser beams MBa and MBb are elongated rods, they are diffused and outputted from the end face forming the selective output portion 18a, and are made uniform. The detected light is received by the photodiode 20 and accurate detection is performed. The photodiode 20 is preferably provided with a shielding plate 21 as a shielding means for shielding the scattered light in the chamber 17 from entering. Thereby, the detection accuracy of only the output light of the two laser diodes 9a and 9b can be improved.

  Between the laser diode 9b that outputs the laser beam MBb reflected on the surface side of the inclined surface 19a and the polarization beam splitter 19, a wave plate 40 that rotates the oscillation direction of the laser beam MBb is provided. It is supported so as to be rotatable with a rotation shaft 41 that is orthogonal to the optical axis and parallel to the paper surface in FIG. 2, and is arranged so as to be inclined from a position orthogonal to the optical axis. In the present embodiment, a half-wave plate 40 is provided. When the half-wave plate 40 is rotated, the optical axis of the transmitted laser beam MBb can be moved in the height direction as shown by the solid line and the broken line in FIG. Both laser beams MBa and MBb output from both laser diodes 9a and 9b oscillate in a direction (see arrows a and b) parallel to the paper surface and perpendicular to the optical axis in FIG. When the laser beam MBb passes through the half-wave plate 40, the vibration direction is rotated in the direction perpendicular to the paper surface (see display by black circles in FIG. 2). As a result, in the combined laser beams MBa and MBb traveling from the surface side of the inclined surface 19a of the polarization beam splitter 19, one laser beam MBa vibrates parallel to the paper surface, and the other excitation laser light MBb is perpendicular to the paper surface. It vibrates in the direction (refer to the display by the arrow and black circle on the optical axis on the downstream side of the inclined surface 19a in FIG. 2). In the present embodiment, as shown in FIG. 5, the incident points (condensing positions) of the two laser beams MBa and MBb that become incident light reaching the end face 7a (output reference plane) of the optical fiber 7 for transmission are used. When the height position is shifted as shown in FIG. 5A, the half-wave plate 40 is rotated to move the height position of one of the laser beams MBb. ), The height positions of both laser beams MBa and MBb can be matched.

  In FIG. 2, a reflection plate 24 is provided on the downstream side of the optical system of the polarization beam splitter 19 so as to reflect the combined laser beams MBa and MBb toward the condensing lenses 23a and 23b on the optical path. By bending the optical path by the reflector 24 in this way, the laser diode unit 9 can be prevented from being elongated and downsized. The laser beams MBa and MBb reflected by the reflection plate 24 are respectively transmitted to one end face 7a of the transmission optical fiber 7 connected to the chamber 17 of the laser diode unit 9 by the condensing lenses 23a and 23b. The light is condensed so as to be focused, and is emitted to the outside of the unit 9 through the optical fiber 7. At this time, the laser beams MBa and MBb are condensed in the width direction of the laser beams MBa and MBb (in the direction parallel to the paper surface of FIG. 2) by the fast-side condenser lens 23a, respectively, and then the slow-side condenser lens. The laser beams MBa and MBb are condensed in the height direction (perpendicular to the paper surface of FIG. 2) by 23b. When the laser diode unit 9 is set, the laser beams MBa and MBb thus collected are changed to the optical fiber 7 and an incident portion of a CCD camera is attached to collect the laser beams MBa and MBb on the end face 7a. While measuring the light position, the half-wave plate 40 is rotated to set the condensing positions of the laser beams MBa and MBb (see FIG. 5). Thereafter, in the present embodiment, the laser beams MBa and MBb emitted from the other end face 7b of the optical fiber 7 are collimated by the collimating lens 23c, enter the optical resonator mirror 11, and then enter the excitation laser beam MB. It is formed to be used as.

  In order to dissipate heat generated by oscillation, each laser diode 9a, 9b has a Peltier element 25 on the upper surface of a bottom plate 17a in a metal chamber 17 formed in a sealable box shape as shown in FIG. The laser diodes 9a and 9b are stacked and arranged on the upper part of the Peltier element 25 (in this embodiment, with a metal plate 26 interposed), and a heat sink 27 is attached to the lower surface of the bottom plate 17a of the chamber 17 ing. Furthermore, a heat insulating layer 28 is provided to prevent heat from being transferred from the bottom plate 17a portion of the chamber 17 to the side walls 17b and the upper portions of the lid portions 17c. The heat insulating layer 28 may be formed over the entire periphery of the side wall 17b connected to the bottom plate 17a of the chamber 17, and a material having high heat insulating efficiency such as a resin material (for example, PPS: polyphenylene sulfide resin). It is good to form by. Cooling power is supplied to the Peltier element 25 from the outside. The metal plate 26 can be omitted.

  Returning to FIG. 1, the optical system ahead of the laser incident portion 3 will be described in the order in which the fiber laser beam FB travels. That is, the fiber laser beam FB that has entered the laser incident portion 3 is first folded in a predetermined direction by the vent mirror 29 and then condensed by the condenser lens 31 in the incident unit 30 to be transmitted light from the fiber transmission portion 4. The light enters the one end surface of the fiber 32. The transmission optical fiber 32 is made of, for example, an SI (step index) fiber, and transmits the fiber laser light FB incident in the incident unit 30 to the emission unit 33 of the laser head unit 5. The emission unit 33 includes a collimator lens 34 that collimates the fiber laser light FB emitted from the end surface of the transmission optical fiber 32 into parallel light, and a condensing lens that condenses the parallel fiber laser light FB at a predetermined focal position. 35, and the fiber laser beam FB is focused and applied to the processing point W of the workpiece 36 placed on the processing table 6.

  Next, the operation of the laser diode unit for laser processing according to this embodiment will be described.

  In the present embodiment, the Peltier element 25, the metal plate 26, and the laser diodes 9a and 9b are sequentially stacked on the upper surface of the bottom plate 17a in the chamber 17 that is formed in a box shape that forms the laser diode unit 7. A heat sink 27 is attached to the lower surface of the bottom plate 17a, and the Peltier element 25 is energized to cool both laser diodes 9a and 9b. In this case, in the present embodiment, since the heat insulating layer 28 is provided to prevent heat from being transmitted from the bottom plate 17a portion of the chamber 17 to the upper portion, heat transfer from the bottom plate 17a portion to the lid portion 17c of the ceiling portion is performed. Is definitely prevented. As a result, according to the present embodiment, the two laser processing laser diodes 9a and 9b built in the chamber 17 can be appropriately cooled, and the oscillation wavelength of the laser light from the laser diodes 9a and 9b is kept constant. The available ambient temperature can be set high. Specifically, the chamber temperature is about 50 ° C. in the conventional laser diode unit, but in the laser diode unit of the present embodiment, the chamber temperature can be reduced by 10 ° C. or more, and the temperature is increased to about 35 ° C. Can be lowered. As a result, the usage environment temperature outside the unit could be set higher by 5 to 10 ° C.

  In addition, by forming the heat insulating layer 28 over the entire circumference of the side wall 17b connected to the bottom plate 17a of the chamber 17, the heat insulating layer 28 ensures heat transfer from the bottom 17a of the chamber 17 to the ceiling. Thus, the oscillation wavelength of the laser light of the laser diodes 9a and 9b can be maintained constant. Furthermore, when the heat insulating layer 28 is formed of a resin material such as PPS (polyphenylene sulfide resin), the heat insulating effect is high, so that the oscillation wavelength of the laser light of the laser diodes 9a and 9b can be more reliably maintained constant.

  Next, a laser processing method using both the laser diodes 9a and 9b properly air-cooled in this way will be described.

  First, when an excitation current is supplied from the laser power supply unit 22 to both laser diodes 9a and 9b of the laser oscillation unit 2, the laser diodes 9a and 9b oscillate laser beams MBa and MBb, respectively.

  The laser beam MBa composed of laterally polarized light output from one laser diode 9a passes through the inclined surface 19a of the polarizing beam splitter 19 that is mostly the optical combiner 18 from the back surface side to the front surface side, and travels straight. A part (for example, 1%) is reflected from the back surface side of the inclined surface 19a and output from the end surface serving as the selective output unit 18a. The laser beam MBb composed of laterally polarized light output from the other laser diode 9b is transmitted through the half-wave plate 40, the polarization direction is rotated by 45 °, and becomes longitudinally polarized light. The laser beam MBb, which has become vertically polarized light, has its incident point (condensing position) on the end face 7a of the optical fiber 7 of one laser beam MBa coincided with its own incident point (condensing position). Most of the light is reflected on the surface side of the inclined surface 19a, and merges with one laser beam MBa that has passed through the inclined surface 19a from the back surface side to the front surface side, and proceeds in the forward direction. ) Passes through the inclined surface 19a from the front surface side to the back surface side, and is output from the end surface serving as the selective output portion 18a.

  A part of the laser beams MBa and MBb, which are the output lights of the two laser diodes 9a and 9b output from the end face forming the selective output portion 18a of the polarization beam splitter 19, are received by the photodiode 20 and the intensity thereof is increased. Detected. Thereby, the outputs of the laser diodes 9a and 9b can be accurately detected.

  Return light may travel in the opposite direction from the downstream side to the optical combiner 18. The return light is reflected light at the incident end face 7 a of the optical fiber 7 connected to the laser diode unit 9, reflected light from various optical elements provided before and after the optical fiber 7, and the like. The return light of one laser beam MBa does not travel to the photodiode 20 because it passes through the inclined surface 19a of the optical combiner 18 from the front side to the back side. The return light of the other laser beam MBb is reflected on the surface side of the inclined surface 19a of the optical combiner 18 and travels toward the laser diode 9b, so that it does not travel to the photodiode 20. Thus, in this embodiment, the output state of the laser diodes 9a and 9b for laser processing can be accurately detected without being affected by the return light, and high-quality laser processing can be performed.

  Further, when a diffusing means for diffusing the output light from the end face forming the selective output unit 18a is provided in the selective output unit 18a of the polarization beam splitter 19, by adopting a multi-emitter structure as both laser diodes 9a and 9b, Even if the laser beams MBa and MBb are in the form of elongated bars, they are diffused and outputted from the end face forming the selective output portion 18a, and the uniformed light is received by the photodiode 20 and accurate detection is executed. The In this case, even if a part of the laser diodes 9a and 9b having the multi-emitter structure is malfunctioning, the laser beams MBa and MBb uniformized by the diffusing means can be detected by the photodiode.

  In addition, if a shielding plate 21 is provided as a shielding means for shielding the scattered light from the chamber 17 from entering the photodiode 20, the detection accuracy of only the output light from the two laser diodes 9a and 9b is improved. Can do.

  The laser beams MBa and MBb output from both laser diodes 9a and 9b and merged by the optical combiner 18 are reflected so as to be folded back by the reflecting plate 24, and collected on the incident end face 7a of the optical fiber 7 by the condenser lenses 23a and 23b. Light is incident. The laser beams MBa and MBb incident on the optical fiber 7 propagate through the optical fiber 7 and are emitted from the end face 7b on the emission side, and are used for laser processing.

  In this embodiment, since the laser beams MBa and MBb are used for excitation, the laser beams MBa and MBb propagate through the optical fiber 7 and are emitted from the end face 7b on the emission side toward the optical resonator mirror 11. Then, the optical resonator mirror 11 transmits the combined pumping laser beam MB and totally reflects the oscillation beam incident from the oscillation fiber 10 side. The optical lens 13 condenses the incident excitation laser beam MB on one end face of the oscillation fiber 10. The optical lens 13 collimates the oscillating light beam emitted from the end face of the oscillating fiber 10 into parallel light.

  Next, the merged excitation laser beam MB incident on one end face of the oscillation fiber 10 propagates in the axial direction inside the oscillation fiber 10 while being confined by total reflection at the cladding outer peripheral interface, The core ions are photoexcited by crossing many times. Thereby, an oscillation light beam having a predetermined wavelength is emitted in the axial direction from both end faces of the core. The oscillation light beam is resonantly amplified by traveling back and forth between the optical resonator mirrors 11 and 12 through the optical lenses 13 and 14, and the fiber laser beam FB having a predetermined wavelength is transmitted through the optical resonator mirror 12. can get.

  The fiber laser beam FB output from the optical resonator mirror 12 passes straight through the folding mirror 15, is reflected by the vent mirror 29, enters the laser incident portion 3, and is used for processing the workpiece 36. On the other hand, when the excitation laser beam MB combined before obtaining the fiber laser beam FB of a predetermined wavelength passes through the optical lens 13 and the optical resonator mirror 14, it is folded back in the direction of the laser absorber 16 by the folding mirror 15. It is.

  The fiber laser beam FB that has entered the laser incident portion 3 is first folded back in a predetermined direction by the vent mirror 29, and then condensed by the condenser lens 31 in the incident unit 30 to be transmitted by the transmission optical fiber 32 of the fiber transmission portion 4. It is incident on one end face of. The transmission optical fiber 32 transmits the fiber laser beam FB incident in the incident unit 30 to the emission unit 33 of the laser head unit 5. The emission unit 33 performs laser processing by condensing and irradiating the fiber laser beam FB to the processing point W of the workpiece 36 placed on the processing table 6.

  In this way, in the present embodiment, high-quality laser processing can be executed with the fiber laser beam FB having an appropriate output.

  In addition, this invention is not limited to said embodiment, It can change as needed.

  For example, as indicated by a broken line in FIG. 2, the output of the photodiode 20 can be fed back to the control unit 42 that controls the output of the laser power supply unit 22 to control the output of the laser diodes 9a and 9b. The control unit 42 compares the detection output from the photodiode 20 with the set output of both the laser diodes 9a and 9b, and instructs the laser power supply unit 22 to output so that both the laser diodes 9a and 9b maintain the set output. To do. Thus, both laser diodes 9a and 9b can receive the excitation power instructed by the feedback from the laser power supply unit 22 and output appropriate laser beams MBa and MBb. Thereby, the excitation light of a laser processing apparatus can be controlled appropriately.

  The configuration in which the output of the photodiode is fed back to the control unit in this way is preferably applied to a so-called LD direct type laser processing apparatus that directly irradiates the workpiece with the laser beam output from the laser diode unit. it can.

DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 2 Laser oscillation part 8 Oscillator unit 9 Laser diode unit 9a, 9b Laser diode 10 Oscillation fiber 17 Chamber 17a Bottom plate 18 Optical combiner 19 Polarizing beam splitter 20 Photodiode 25 Peltier device 27 Heat sink 28 Heat insulation layer

Claims (3)

In a laser diode unit in which a Peltier element is stacked on the top surface of a bottom plate in a chamber formed in a box shape, a laser diode is stacked on the top of the Peltier element, and a heat sink is attached to the bottom surface of the bottom plate.
A laser diode unit comprising a heat insulating layer for preventing heat from being transferred from the bottom plate portion of the chamber to the top.   The said heat insulation layer is formed over the perimeter along this side wall between the bottom plate of the said chamber, and the side wall provided in a row with the said bottom plate. Laser diode unit.   The laser diode unit according to claim 1, wherein the heat insulating layer is formed of a resin material.

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