JP2011119342A - Laser diode cooling mechanism and laser device equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser diode cooling mechanism capable of improving cooling efficiency while suppressing an adverse influence on earth environment, and a laser device equipped with the same. <P>SOLUTION: The laser device 10 includes a plurality of laser diodes 24a, 24b and 24c supported by a support base 20, and the laser diode cooling mechanism 40 which cools the plurality of laser diodes 24a, 24b and 24c. The laser diode cooling mechanism 40 is provided with an installation member 42 as a heat sink provided to the support base 20, a Peltier element 44 provided between the installation member 42 and the respective laser diodes 24a, 24b and 24c, and a stirling cooler 46 having a heat absorption portion 56 provided to the installation member 42 and cooling the installation member 42. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser diode cooling mechanism for cooling a laser diode and a laser apparatus including the same.

  Conventionally, laser diodes (LDs) have been widely used in fields such as thermal processing. It is known that the LD generates considerable heat during laser oscillation and deteriorates due to thermal stress when the temperature is higher than a predetermined temperature. For this reason, the LD is usually cooled in order to suppress an excessive temperature rise of the LD.

  As the LD cooling mechanism, for example, a water cooling type cooling mechanism, a chiller cooler, and an air cooling type cooling mechanism are known.

  The water cooling type cooling mechanism may not be used in an environment where use of water is not preferable, such as a lithium ion battery manufacturing factory.

  The chiller cooler uses chlorofluorocarbon, HFC (hydrofluorocarbon) or the like as a refrigerant, and thus may adversely affect the global environment.

  As the air-cooling type cooling mechanism, a heat sink, a Peltier element, and the like are known (see Patent Document 1).

JP 2006-5212 A

  In recent years, it has been desired to develop an LD capable of oscillating a high-power laser. For this reason, it is essential to increase the cooling efficiency of a cooling mechanism that cools the LD.

  The present invention has been made in consideration of such problems, and an object of the present invention is to provide a laser diode cooling mechanism capable of improving cooling efficiency while suppressing adverse effects on the global environment, and a laser device including the same. And

  The laser diode cooling mechanism according to the present invention includes an installation member on which a laser diode is provided, and a Stirling cooler provided on the installation member and having a heat absorption part that cools the laser diode.

  According to such a configuration, since the Stirling cooler is used, the cooling efficiency can be increased as compared with the case where only the heat sink or the Peltier element is used. In addition, since no chlorofluorocarbon or HFC is used, adverse effects on the global environment can be suppressed. Furthermore, since water is not used, it can be suitably used even in an environment where the use of water is not preferable.

  Moreover, the said heat absorption part of the said Stirling cooler may be provided in the position where the temperature of the said installation member becomes the highest when the said laser diode is driving.

  If it does so, when the laser diode is driving, the part with the highest temperature of an installation member can be cooled preferentially. Thereby, concentration of the heat energy to a part of the installation member can be avoided. That is, heat can be smoothly transferred from the laser diode to the installation member. Therefore, the cooling efficiency of the laser diode can be further increased.

  The installation member may be a heat sink. Thereby, the heat generated in the laser diode can be efficiently released to the heat sink.

  A plurality of the laser diodes may be provided, and a Peltier element may be provided between each laser diode and the installation member.

  By electrically controlling the Peltier element, the temperature of each laser diode can be arbitrarily adjusted by transmitting the heat of the laser diode to the installation member. That is, by electrically controlling the Peltier element, for example, the temperature of the plurality of laser diodes can be made constant, or the temperature of each laser diode can be made different.

  A laser apparatus according to the present invention includes a laser diode, an installation member provided with the laser diode, and a Stirling cooler provided on the installation member and having a heat absorption part that cools the laser diode. And

  According to such a configuration, since the laser diode is cooled using the Stirling cooler, the cooling efficiency can be improved while suppressing adverse effects on the global environment.

  According to the present invention, since the Stirling cooler is used, the cooling efficiency can be increased as compared with the case where a heat sink or a Peltier element is used. In addition, since no chlorofluorocarbon or HFC is used, adverse effects on the global environment can be suppressed. Furthermore, since water is not used, it can be suitably used even in an environment where the use of water is not preferable.

It is a block diagram of a laser device incorporating a laser diode cooling mechanism according to the present invention. It is a partially omitted enlarged longitudinal sectional view along the optical axis of the second unit. It is sectional drawing along the III-III line of FIG. It is the flowchart which showed the laser processing procedure of the laser apparatus which concerns on this embodiment. It is a graph which shows the temperature distribution of the installation member in the state in which the laser diode was driven. It is explanatory drawing for demonstrating the horizontal axis of FIG.

  Hereinafter, preferred embodiments of a laser diode cooling mechanism according to the present invention and a laser device in which the laser diode cooling mechanism is incorporated will be exemplified and described in detail with reference to the accompanying drawings.

  The laser apparatus according to the present embodiment is an apparatus that emits high-power (for example, about 100 W to 300 W) laser light by synthesizing a plurality of laser lights, and is used for processing, welding, cutting, or the like of a workpiece. It is done.

  First, the basic configuration of the laser apparatus according to this embodiment will be described. As shown in FIG. 1, the laser device 10 includes a pair of laser output units 12a and 12b that output a plurality of laser beams, a combining unit 14 that combines the plurality of laser beams, and a combination with the laser output units 12a and 12b. And an output unit 18 that condenses the combined laser beam (synthetic laser beam) onto the workpiece W disposed on the table 17.

  As shown in FIGS. 1 to 3, the laser output units 12a and 12b have first to third units 22a, 22b, and 22c supported by the support base 20, and each unit 22a, 22b, and 22c includes Laser diodes (LD) 24a, 24b, and 24c that output the laser light are provided, and an optical fiber 16 that transmits the laser light output from the LDs 24a, 24b, and 24c is connected by connection connectors 26a, 26b, and 26c. . That is, as shown in FIG. 1, three optical fibers 16 are connected to the laser output units 12a and 12b. The first to third units 22a, 22b, and 22c are arranged in parallel in one direction, and the laser output units 12a and 12b are arranged so that the connection connectors 26a, 26b, and 26c of the units 22a, 22b, and 22c face each other. Has been placed.

  In the following description, the subscripts “a”, “b”, or “c” are added to the reference numerals when distinguishing the first to third units and their components, and the subscripts are appended when they are not distinguished. Omit the letter.

  As shown in FIGS. 1 to 3, the unit 22 includes a casing 28 that accommodates the LD 24. In the casing 28, a collimating lens 30 that collimates the laser light output from the LD 24, and a collimating lens. Condensing lenses 32 and 34 for condensing the laser light collimated at 30 are provided. Moreover, each unit 22a, 22b, 22c is arrange | positioned so that the casings 28 may contact. In addition, the condensing lens 32 condenses a laser beam to the left-right direction, and the condensing lens 34 condenses a laser beam to an up-down direction.

  As shown in FIG. 1, the three optical fibers 16 connected to the laser output units 12a and 12b are connected to the combining unit 14 in a bundled state. In the following description, a portion where the three optical fibers 16 are bundled may be referred to as a bundle portion 16a. As can be understood from FIG. 1, the bundle portion 16a extends along the direction in which the first to third units 22a, 22b, and 22c are arranged.

  Each unit 22a, 22b, 22c is inclined such that the output direction of the laser beam is inclined by a predetermined angle toward the bundle portion 16a with respect to the direction orthogonal to the direction in which the first to third units 22a, 22b, 22c are arranged. Is set to Thereby, the optical fiber 16 is gently curved between the bundle portion 16 a and the connection connector 26. Therefore, breakage of the optical fiber 16 can be prevented.

  The combining unit 14 combines the six laser beams guided from the laser output units 12a and 12b through the optical fiber 16 into one.

  The emission unit 18 includes a collimator lens 36 that collimates the synthesized laser beam emitted from the synthesis unit 14 and a condenser lens 38 that collects the synthesized laser beam collimated by the collimator lens 36 onto the workpiece W. .

  Next, the laser diode cooling mechanism (LD cooling mechanism) 40 according to this embodiment will be described. As shown in FIGS. 1 to 3, the LD cooling mechanism 40 is for cooling the LD 24, and an installation member 42 on which the LD 24 is installed, and a Peltier element arranged between the LD 24 and the installation member 42. 44 and a Stirling cooler 46 provided on the installation member 42.

  As shown in FIGS. 2 and 3, the installation member 42 is formed in a plate shape in a state of being provided on the support base 20. The installation member 42 is formed as a heat sink, for example, and is made of an aluminum material or a copper material. Thereby, the heat transmitted to the installation member 42 can be efficiently radiated. The installation member 42 is provided with a temperature detection unit 48 as temperature detection means for acquiring the temperature of the installation member 42 (see FIG. 3).

  The Peltier element 44 has the LD 24 in contact with the upper surface and the installation member 42 in contact with the lower surface. Further, the Peltier element 44 is configured such that when the current is supplied, the upper surface absorbs heat and the lower surface dissipates heat.

  Although not specifically shown, the Stirling cooler 46 cools an object to be cooled by, for example, reciprocating a piston in the cylinder to compress and expand helium gas, and is fixed to the support base 20. The main body part 50, the cylindrical part 52 extending from the main body part 50 to the installation member 42, and the heat radiating part 54 located on the opposite side of the cylindrical part 52 across the main body part 50 are included. In addition, the Stirling cooler 46 is disposed so that the center line of the cylindrical portion 52 is positioned at the approximate center of the LD 24b of the second unit 22b.

  As shown in FIG. 3, a heat absorbing portion 56 that is cooled by the expansion action of helium gas is provided near the tip of the cylindrical portion 52. The heat absorbing portion 56 is located inside the installation member 42 with its outer surface in surface contact with the installation member 42. Thereby, the installation member 42 is more efficiently compared with the case where the heat absorption unit 56 is located in the installation member 42 in a state where some gap is formed between the outer surface of the heat absorption unit 56 and the installation member 42. It becomes possible to cool.

  The heat radiating part 54 is disposed at a position separated from the support 20 and radiates heat generated by the compression action of helium gas.

  Next, the above-described LD cooling mechanism 40 and the control unit 58 that controls the laser apparatus 10 including the LD cooling mechanism 40 will be described with reference to FIG.

  The controller 58 controls the output of the laser beam by applying a voltage to the LD 24 or stopping the voltage application to the LD 24.

  The control unit 58 includes a storage unit 60, a determination unit 62, a Peltier element control unit 64, and a Stirling cooler control unit 66.

In the storage unit 60, a Stirling cooler drive start temperature (hereinafter referred to as drive start temperature) T ₀ is set and stored in advance. The drive start temperature T ₀ may be set arbitrarily, but for example, is set to be equal to or lower than the temperature acquired by the temperature detector 48 when the LD 24 deteriorates due to thermal stress.

The determination unit 62 determines whether or not the temperature acquired by the temperature detection unit 48 is higher than the drive start temperature T ₀ .

  The Peltier element control unit 64 adjusts the current supplied to the Peltier element 44.

  The Stirling cooler control unit 66 drives the piston of the Stirling cooler 46 to control the frequency of compression / expansion of helium gas. That is, the Stirling cooler control unit 66 controls the degree of cooling of the heat absorbing unit 56.

  Next, the laser processing procedure of the laser apparatus 10 according to the present embodiment will be described with reference to the flowchart of FIG.

  First, the control unit 58 applies a predetermined voltage to the LDs 24a, 24b, and 24c and outputs laser light (step S1). At this time, the LD 24 generates heat. The predetermined voltage is determined based on the machining conditions of the workpiece W. The machining conditions of the workpiece W are input to the control unit 58 by an input unit (not shown) provided in the laser device 10.

  Further, the Peltier element control unit 64 supplies a current to the Peltier element 44 so that the temperature of each LD 24 becomes substantially constant (step S2). Thereby, the heat generated in the LD 24 moves from the upper surface to the lower surface of the Peltier element 44. That is, the LD 24 is cooled by the Peltier element 44. The heat moved to the lower surface of the Peltier element 44 is radiated to the outside by the installation member 42. At this time, the temperature detection unit 48 outputs a signal corresponding to the temperature of the installation member 42.

Subsequently, the determination unit 62 is larger than the operation starting temperature T ₀ of the temperature (acquired temperature) T _a is stored in the storage unit 60 of the installation member 42 with reference to the acquired output signal of the temperature detecting portion 48 Is determined (step S3).

If the acquired temperature T _a is less than the drive start temperature T ₀ (step S3: NO), the process proceeds to step S5, the determination unit 62 determines whether the laser processing is finished. If not completed (step S5: NO), the process returns to step S3. That is, the LD 24 can be sufficiently cooled only by the installation member 42 and the Peltier element 44.

On the other hand, when the acquired temperature T _a is greater than the operation starting temperature T ₀ (step S3: YES), the Stirling cooler controller 66 drives the Stirling cooler 46 (step S4). Thereby, the installation member 42 is cooled by the heat absorption part 56 of the Stirling cooler 46.

  When the laser processing is completed (step S5: YES), the control unit 58 stops driving the LD 24 (step S6).

  Thereafter, the Peltier element control unit 64 stops supplying current to the Peltier element 44 (step S7), and the Stirling cooler control unit 66 stops driving the Stirling cooler 46 (step S8). Note that steps S7 and S8 may be performed after a certain amount of time has elapsed after the operation of step S6 is completed. Thereby, even after the driving of the LD 24 is stopped, the LD 24 is cooled by the LD cooling mechanism 40. Therefore, it is possible to prevent the LD 24 from being deteriorated by heat stress after the driving of the LD 24 is stopped.

  Next, functions and effects of the LD cooling mechanism 40 according to the present embodiment and the laser apparatus 10 including the LD cooling mechanism 40 will be described with reference to FIGS. 5 and 6.

  FIG. 5 is a graph showing the temperature distribution of the installation member 42 in a state where the LD 24 is driven, and the horizontal axis is the first to third units 22a, 22b, and 22c based on the line segment X0 passing through the center of the second LD 24b. (See FIG. 6), and the vertical axis indicates the temperature. As shown in FIG. 6, the line segment X0 is located on the central axis of the cylindrical portion 52 of the Stirling cooler 46, the distance from the center of the second LD 24b to the center of the first LD 24a, and the center of the second LD 24b. And the distance from the center of the third LD 24c to X3.

  In FIG. 5, a solid line L1 indicates the temperature distribution of the installation member 42 in a state where the Stirling cooler 46 is not driven, and a broken line L2 indicates the temperature distribution of the installation member 42 in a state where the Stirling cooler 46 is driven. Yes.

  As can be seen from FIG. 5, when the laser beam is output by driving the LD 24, the second LD 24b is sandwiched between the first LD 24a and the third LD 24c. Becomes higher.

  In the present embodiment, since the heat absorbing portion 56 of the Stirling cooler 46 is disposed at the position where the temperature of the installation member 42 is highest, the temperature increase at the position of the line segment X0 is suppressed in the installation member 42. Thereby, the installation member 42 is held at the temperature T2.

  According to the present embodiment, since the Stirling cooler 46 is used for cooling the LD 24, the cooling efficiency can be increased as compared with the case where only the heat sink or the Peltier element is used. Further, since the Stirling cooler 46 uses helium as the refrigerant and does not use Freon, HFC, or the like, adverse effects on the global environment can be suppressed. Furthermore, since water is not used, it can be suitably used even in an environment where the use of water is not preferable.

  In the present embodiment, as described above, when the LD 24 is being driven, the heat absorbing portion 56 of the Stirling cooler 46 is disposed at a portion where the temperature of the installation member 42 is the highest, so the temperature of the installation member 42 is the highest. Higher parts can be preferentially cooled. Thereby, concentration of thermal energy on a part of the installation member 42 can be avoided. That is, heat transfer from the LD 24 to the installation member 42 can be made smooth. Therefore, the cooling efficiency of the LD 24 can be further increased.

  The present invention is not limited to the above-described embodiment, and it is naturally possible to adopt various configurations without departing from the gist of the present invention.

  The Peltier device control unit according to the present invention may supply a current to the Peltier device of each unit so that each LD has a different temperature.

  The LD cooling mechanism according to the present invention may omit the Peltier element and install the LD directly on the upper surface of the installation member. Further, the installation member may not be a heat sink, and may be configured as an optical base, for example. The optical base is made of a metal material, a composite material, ceramic, or the like. As the metal material, copper (Cu), aluminum (Al), stainless steel (SUS), or the like can be used. Note that when the optical base is made of copper, the heat dissipation effect can be enhanced because of its relatively high thermal conductivity. As the composite material, a composite material of copper and diamond (copper diamond), a composite material of silver and diamond (silver diamond), or the like can be used.

  The laser output unit according to the present invention is not limited to an example having three LDs. For example, the laser output unit may have four or more LDs, and may have one or two LDs. In any configuration, it is desirable to dispose the Stirling cooler corresponding to the position where the temperature of the installation member is highest.

  The laser device according to the present invention may be a laser device (fiber laser device) including an LD that irradiates an optical fiber having a core doped with a rare earth element with excitation light.

  The present invention is not limited to the example in which the heat absorption part of the Stirling cooler is located inside the installation member, and the installation location of the Stirling cooler may be arbitrarily selected. For example, you may arrange | position a Stirling cooler so that a part or all of the said heat absorption part may be located in the casing of a 2nd unit. In this case, the Stirling cooler can cool the LD using air in the casing as a medium.

DESCRIPTION OF SYMBOLS 10 ... Laser apparatus 12a, 12b ... Laser output part 20 ... Support stand 24a, 24b, 24c ... Laser diode 40 ... Laser diode cooling mechanism 42 ... Installation member 44 ... Peltier element 46 ... Stirling cooler 56 ... Heat absorption part

Claims (5)

An installation member provided with a laser diode;
A laser diode cooling mechanism, comprising: a Stirling cooler provided on the installation member and having a heat absorbing portion for cooling the laser diode. The laser diode cooling mechanism according to claim 1, wherein
The laser diode cooling mechanism, wherein the heat absorption part of the Stirling cooler is provided at a position where the temperature of the installation member is highest when the laser diode is driven. The laser diode cooling mechanism according to claim 1 or 2,
The laser diode cooling mechanism, wherein the installation member is a heat sink. The laser diode cooling mechanism according to claim 2 or 3,
A plurality of the laser diodes are provided,
A laser diode cooling mechanism, wherein a Peltier element is provided between the installation member and the laser diode. A laser diode;
An installation member provided with the laser diode;
A laser apparatus comprising: a Stirling cooler provided on the installation member and having a heat absorption part for cooling the laser diode.

Images