LASER EQUIPMENT AND LASER PROCESSING MACHINE

Abstract

A laser device (1A) comprises the following: a first laser device (LD1) in which light-emitting points arranged in one direction of the y-axis form a first beam group (B1); a second laser device (LD2) in which light-emitting points arranged in one direction of the y-axis form a second beam group (B2); an output coupler (14) forming one end of an external resonator that reflects part of the first and second beam groups and transmits the remainder; a converging optical system (11) that allows the first and second beam groups to strike the converging optical system non-parallel and on one side of a subsequent stage, causing the first beam group to converge as it is superimposed, and causing the second beam group to converge as it is superimposed;a diffraction grating (12) arranged at an intersection point (120) where at least part of the first and second groups of rays are superimposed, and exhibiting a diffraction effect in a plane (50) perpendicular to a third direction, which is a direction perpendicular to a first and second direction; and a collimating optical system (13) arranged between the diffraction grating and the output coupler, collimating the first and second groups of rays such that the first and second groups of rays strike the output coupler perpendicularly while being spatially separated from each other.

Description

Area

[0001] The present disclosure relates to a laser device and a laser processing machine, wherein the laser device amplifies a beam and couples out laser light. General state of the art

[0002] In a laser device that amplifies a beam and outputs laser light, a laser device and an output mirror each form one end of a laser resonator. One such laser device is a laser device equipped with laser devices that emit beams from a plurality of light-emitting points positioned in a horizontal direction to increase the output of laser light. This laser device increases the output of laser light by superimposing the beams emitted from the plurality of light-emitting points through a diffraction grating.

[0003] A laser device described in Patent Literature 1 includes a plurality of laser devices stacked in a vertical direction and outputs laser light beams equal in number to the number of the stacked laser devices, thereby outputting high-power laser light. List of citationsPatent literature

[0004] Patent Literature 1: US Patent No. 8,488,245 Brief description of the inventionProblem to be solved by the invention

[0005] However, in the technique of Patent Literature 1, the laser devices are stacked in the vertical direction, so the vertical dimension of a diffraction grating increases proportionally with the number of stacked laser devices. For example, in a case where two layers of laser devices are stacked in the vertical direction, the vertical dimension of the diffraction grating doubles. This leads to a problem in that the diffraction grating becomes expensive.

[0006] The present disclosure has been developed in view of the foregoing, and an object thereof is to provide a laser device capable of extracting high-power laser light using a diffraction grating that is small in size and inexpensive. Means to solve the problem

[0007] To solve the above problem and achieve the object, a laser device of the present disclosure includes: a first laser device that emits a beam from each of a plurality of light-emitting points arranged in a first direction in a first emission direction perpendicular to the first direction and forms a first beam group; and a second laser device that emits a beam from each of a plurality of light-emitting points arranged in a second direction in a second emission direction perpendicular to the second direction and forms a second beam group.The laser device of the present disclosure further includes: an output mirror forming one end of a first external resonator whose other end is formed by the first laser device, forming one end of a second external resonator whose other end is formed by the second laser device, and including a partial reflection surface that reflects part of the first beam group and the second beam group and transmits the rest; and a converging optical system that allows non-parallel incidence of the first beam group and the second beam group on the converging optical system and, on a side of a subsequent stage, converges the first beam group so that the first beam group is superimposed, and converges the second beam group so that the second beam group is superimposed.The laser device of the present disclosure further includes: a diffraction grating disposed at an intersection point where at least a part of the first beam group and the second beam group is superimposed, and having a diffraction effect in a first plane perpendicular to a third direction, which is a direction perpendicular to the first direction and the second direction; and a collimating optical system disposed between the diffraction grating and the output mirror, which collimates the first beam group and the second beam group so that the first beam group and the second beam group are perpendicularly incident on the partial reflection surface while being spatially separated from each other. Effects of the invention

[0008] The laser device according to the present disclosure has the effect of being able to extract high-power laser light using the diffraction grating, which is small and inexpensive. Short description of the drawings Fig. 1 is a diagram illustrating a configuration of a laser processing machine including a laser device according to a first embodiment. Fig. 2 is a schematic diagram illustrating a schematic configuration of a laser device according to the first embodiment. Fig. 3 is a diagram illustrating a configuration of a laser device according to the first embodiment in a case where a collimating optical system consists of two cylindrical lenses. Fig. 4 is a diagram illustrating a configuration of a laser device according to the first embodiment in a case where the collimating optical system is composed of a cylindrical lens. Fig. 5 is a schematic diagram illustrating a schematic configuration of a laser device according to the second embodiment. Fig. 6 is a diagram illustrating a configuration of a laser device according to the second embodiment in a case where an overlay optical system is composed of two eccentric lenses. Fig. 7 is a diagram illustrating a configuration of a laser device according to the second embodiment in a case where the superimposed optical system consists of two deflection mirrors. Fig. 8 is a schematic diagram illustrating a schematic configuration of a laser device of a comparative example. Description of embodiments

[0009] Hereinafter, a laser device and a laser processing machine according to embodiments of the present disclosure are described in more detail with reference to the drawings. First embodiment.

[0010] Fig. 1 is a diagram illustrating a configuration of a laser processing machine including a laser device according to a first embodiment. A laser processing machine 100 is a machine that irradiates a workpiece 6, which is an object to be processed, with laser light 7 and processes the workpiece 6. The processing performed by the laser processing machine 100 is laser processing, such as cutting or welding the workpiece 6.

[0011] The laser processing machine 100 includes a laser device 1 that emits the laser light 7, an optical fiber 4 through which the laser light 7 propagates, a concentrating optical system 3, and a processing optical system 5. The concentrating optical system 3 concentrates the laser light 7 emitted from the laser device 1 onto an incident surface of the optical fiber 4. The optical fiber 4 is an example of an optical transmission line that transmits the laser light 7. The optical fiber 4 transmits the laser light 7 to the processing optical system 5. The processing optical system 5 concentrates the laser light 7 emerging from the optical fiber 4 onto the workpiece 6.

[0012] The workpiece 6 is, for example, a metal plate made of iron, stainless steel, or the like. The laser processing machine 100 can perform laser processing on the metal plate by incorporating the laser device 1 suitable for high-power applications. The configuration of the laser processing machine 100 described in this document is an example and can be modified as needed. The laser device 1 can also be applied to a 3D printer or the like in combination with a configuration of a well-known laser processing machine. As with the laser device 1, a laser device to be described in a second and subsequent embodiments can also be applied to the laser processing machine 100 that cuts or welds the workpiece 6, or to another laser processing system.

[0013] Fig. 2 is a schematic diagram illustrating a schematic configuration of a laser device according to the first embodiment. Fig. 2 illustrates an x-axis, a y-axis, and a z-axis of a three-axis orthogonal coordinate system. The y-axis and the z-axis are two axes that are orthogonal to each other and lie in a plane parallel to a surface that is a flat surface, which is either a beam incident surface or a beam exit surface of a converging optical system 11. Furthermore, an axis that is orthogonal to the y-axis and the z-axis is the z-axis. For example, an xy plane is a horizontal plane. In this case, a direction of the z-axis is a vertical direction. Fig. 2 illustrates a configuration of a laser device 1A as an example of the laser device 1 when the laser device 1A is viewed from a y-axis direction.

[0014] The laser device 1A includes a first laser device LD1 and a second laser device LD2 as laser devices. The laser device 1A further includes the converging optical system 11, a diffraction grating 12, a collimating optical system 13, and an output coupling mirror 14.

[0015] The converging optical system 11 is arranged one stage after the first laser device LD1 and the second laser device LD2, and the diffraction grating 12 is arranged one stage after the converging optical system 11. In addition, the collimating optical system 13 is arranged one stage after the diffraction grating 12, and the output mirror 14 is arranged one stage after the collimating optical system 13.

[0016] In the laser device 1A, the first laser device LD1 and the second laser device LD2 are arranged spaced apart from each other in the z-axis direction. The first laser device LD1 and the second laser device LD2 are not arranged in parallel, and a first beam group B1 emitted by the first laser device LD1 and a second beam group B2 emitted by the second laser device LD2 are not parallel. That is, the first laser device LD1 and the second laser device LD2 are each arranged at an angle such that the first beam group B1 and the second beam group B2 intersect each other at an intersection point 120 to be described later. The first laser device LD1 and the second laser device LD2 emit beams in an in-plane direction parallel to an xz plane.

[0017] In the first laser device LD1, a plurality of light-emitting points are arranged in a first direction, which is a direction parallel to the y-axis direction. The light-emitting points arranged in the first laser device LD1 emit rays having different wavelengths. That is, the first laser device LD1 emits a plurality of rays from the plurality of light-emitting points to form and emit the first ray group B1. The first ray group B1, which is the plurality of rays, includes a plurality of rays having different wavelengths.

[0018] A surface on which the light-emitting points in the first laser device LD1 are arranged is a surface obtained by rotating a surface parallel to a yz plane around an axis that is a direction parallel to the y-axis direction. The first laser device LD1 emits the first beam group B1 in a first emission direction perpendicular to the surface on which the light-emitting points in the first laser device LD1 are arranged. The first emission direction in which the first beam group B1 is emitted is a direction toward the intersection point 120.

[0019] In the second laser device LD2, a plurality of light-emitting points are arranged in a second direction, which is a direction parallel to the y-axis direction. The light-emitting points arranged in the second laser device LD2 emit rays having different wavelengths. That is, the second laser device LD2 emits a plurality of rays from the plurality of light-emitting points to form and emit the second beam group B2. The second beam group B2, which is the plurality of rays, includes a plurality of rays having different wavelengths.

[0020] A surface on which the light-emitting points in the second laser device LD2 are arranged is a surface obtained by rotating a surface parallel to the yz plane around an axis that is the direction parallel to the y-axis direction. The second laser device LD2 emits the second beam group B2 in a second emission direction perpendicular to the surface on which the light-emitting points in the second laser device LD2 are arranged. The second emission direction in which the second beam group B2 is emitted is a direction toward the intersection point 120.

[0021] The rotation angle of the surface on which the light-emitting points are arranged in the first laser device LD1 and the rotation angle of the surface on which the light-emitting points are arranged in the second laser device LD2 are equal in size but opposite in direction of rotation.

[0022] The surface on which the light-emitting points are arranged in the first laser device LD1 and the surface on which the light-emitting points are arranged in the second laser device LD2 are not parallel. Therefore, the first emission direction of the first beam group B1 and the second emission direction of the second beam group B2 are different directions.

[0023] A direction perpendicular to both the first direction in which the light-emitting points are arranged in the first laser device LD1 and the second direction in which the light-emitting points are arranged in the second laser device LD2 is a third direction. Fig. Figure 2 illustrates a case where the first direction and the second direction are both parallel to the y-axis and the third direction is parallel to the z-axis.

[0024] The first beam group B1 and the second beam group B2, which are not parallel to each other, are incident on the converging optical system 11. The converging optical system 11 causes the first beam group B1 to converge to be superimposed on the diffraction grating 12 at the intersection point 120, and causes the second beam group B2 to converge to be superimposed on the diffraction grating 12 at the intersection point 120.

[0025] It should be noted that the converging optical system 11 may include two converging optical systems. In this case, the converging optical system 11 includes a first converging optical system that causes the first beam group B1 to converge to be superimposed on the diffraction grating 12 at the intersection point 120, and a second converging optical system that causes the second beam group B2 to converge to be superimposed on the diffraction grating 12.

[0026] The first beam group B1 and the second beam group B2 exiting the converging optical system 11 intersect at the intersection point 120, which is a point between the first and second laser devices LD1 and LD2 and the output mirror 14. Specifically, the first beam group B1 and the second beam group B2 intersect each other, so that at least parts of the first beam group B1 and the second beam group B2 are superimposed on each other at the intersection point 120, which is a position on the diffraction grating 12.

[0027] It should be noted that the diffraction grating 12 may be arranged at the intersection point 120 or may be arranged near the intersection point 120. That is, the diffraction grating 12 only needs to be arranged at a position (the intersection point 120) where at least parts of the first beam group B1 and the second beam group B2 are superimposed on each other.

[0028] The diffraction grating 12 is a transmission diffraction grating. The diffraction grating 12 exhibits a diffraction effect in a plane (first plane) of a plane 50 parallel to the xy plane. The diffraction grating 12, with its wavelength dispersion property, deflects each ray of the first beam group B1 and each ray of the second beam group B2 in the plane 50. The diffraction grating 12 thus rotates the first beam group B1 and the second beam group B2 around a rotation axis set in an axial direction parallel to the z-axis direction and transmits the first beam group B1 and the second beam group B2 to the collimating optical system 13.That is, the diffraction grating 12 diffracts the first beam group B1 and the second beam group B2 by changing components of the first beam group B1 and the second beam group B2 in the x-axis direction and the y-axis direction while maintaining components thereof in the z-axis direction.

[0029] The diffraction grating 12 diffracts each of the beams included in the beam group at an angle corresponding to the wavelength, thereby converging the beams into a single beam. Specifically, the diffraction grating 12 converges the first beam group B1, which includes the plurality of beams dispersed from one another, into a first beam group B1. Similarly, the diffraction grating 12 converges the second beam group B2, which includes the plurality of beams dispersed from one another, into a second beam group B2. The laser device 1A can thus improve the beam concentrating performance.

[0030] The concentration performance referred to here is a property represented by a beam parameter product (SPP). The SPP is an index defined by a product of a radius of a beam waist at the time of concentration and a half-angle of beam divergence after concentration. The SPP is expressed in units of "mm mrad." The smaller the value of the SPP, the higher the concentration property, which means that the beams can be concentrated in a finer range. Because the beams can be concentrated in a finer range, a higher energy density can be obtained. In the application of laser processing, since the energy density is higher, the processing quality and processing speed can be improved.

[0031] Many general transmission diffraction gratings exhibit high diffraction efficiency for one of s-polarized light and p-polarized light, and low diffraction efficiency for the other. For example, in a case where the diffraction grating 12 in the first embodiment is such a transmission diffraction grating, the diffraction grating 12 diffracts 90% or more of the incident s-polarized light and transmits 50% or more of the incident p-polarized light. In this case, it is desirable that the first beam group B1 and the second beam group B2 incident on the diffraction grating 12 contain only s-polarized light.

[0032] However, there is a case where s-polarized light and p-polarized light are mixed in the laser light actually emitted from the laser device. Even the laser light mainly including s-polarized light may contain several percent of p-polarized light. In a case where the first beam group B1 and the second beam group B2, which mainly include s-polarized light, are incident on the diffraction grating 12, p-polarized light included in the first beam group B1 and the second beam group B2 may be transmitted through the diffraction grating 12. In this case, the p-polarized light transmitted through the diffraction grating 12 may become stray light that deviates from a normal optical path of a first external resonator using the first laser device LD1 or a second external resonator using the second laser device LD2.The generation of scattered light can cause a component in the laser device 1A to heat up or a reduction in the concentration power of the output beam. It is therefore desirable for the laser device 1A to be able to reduce the generation of scattered light.

[0033] To reduce the generation of stray light, the laser device 1A can be provided with a polarization separation element. The polarization separation element is installed between the first laser device LD1 and the diffraction grating 12, and between the second laser device LD2 and the diffraction grating 12. The polarization degrees of the first beam group B1 and the second beam group B2 incident on the diffraction grating 12 are increased by the polarization separation elements, whereby the laser device 1A can reduce the generation of stray light.

[0034] The collimating optical system 13 collimates the first beam group B1 and the second beam group B2 such that the first beam group B1 and the second beam group B2 impinge perpendicularly on a partial reflection surface 140 of the output mirror 14 while being spatially separated.

[0035] The output mirror 14 includes the partial reflection surface 140, which reflects part of the first beam group B1 and the second beam group B2 and transmits the rest.

[0036] An incident surface of the partial reflection surface 140, onto which the first beam group B1 and the second beam group B2 impinge, is a single plane. By using the partial reflection surface 140, which has the incident surface as a single plane, an external resonator can be implemented with a simple optical system.

[0037] In the laser device 1A, the first laser device LD1 and the output mirror 14 form the first external resonator, and the second laser device LD2 and the output mirror 14 form the second external resonator. That is, the first external resonator includes the first laser device LD1, which forms one end thereof, and the output mirror 14, which forms the other end thereof. The second external resonator includes the second laser device LD2, which forms one end thereof, and the output mirror 14, which forms the other end thereof.

[0038] The first external resonator is an external resonator that causes resonance of the first beam group B1. The second external resonator is an external resonator that causes resonance of the second beam group B2. The resonance of the first beam group B1 by the first external resonator and the resonance of the second beam group B2 by the second external resonator share the partial reflection surface 140. Furthermore, the first external resonator and the second external resonator share the diffraction grating 12.

[0039] If necessary, an optical element is inserted into the first external resonator to collimate, concentrate, or rotate the first beam group B1. If necessary, an optical element is inserted into the second external resonator to collimate, concentrate, or rotate the second beam group B2.

[0040] Each beam of the first beam group B1 propagates from the first laser device LD1 to the diffraction grating 12 in a direction parallel to the xz plane. Each beam of the first beam group B1 is diffracted by the diffraction grating 12, propagates in a direction non-parallel to the xz plane, and is sent to the collimating optical system 13.

[0041] Each beam of the second beam group B2 propagates from the second laser device LD2 to the diffraction grating 12 in a direction parallel to the xz plane. Each beam of the second beam group B2 is diffracted by the diffraction grating 12, propagates in a direction non-parallel to the xz plane, and is sent to the collimating optical system 13.

[0042] The first beam group B1 and the second beam group B2 are collimated by the collimating optical system 13 and sent to the output mirror 14. The first beam group B1 and the second beam group B2 impinge perpendicularly on the partial reflection surface 140 of the output mirror 14. The first beam group B1 and the second beam group B2 are partially reflected by the partial reflection surface 140 of the output mirror 14, and the remainder is transmitted as the laser light 7.

[0043] As described above, in the laser device 1A, the first beam group B1 and the second beam group B2 are inclined so that the first beam group B1 and the second beam group B2 can intersect each other at the intersection point 120. As a result, the laser device 1A can reduce the incident area of ​​the first beam group B1 and the second beam group B2 incident on the diffraction grating 12, thus avoiding an increase in the size of the diffraction grating 12.

[0044] In addition, the laser device 1A causes the first beam group B1 and the second beam group B2 to impinge on the output mirror 14 while being separated from each other, thereby preventing an increase in beam intensity at the output mirror 14. Therefore, the laser device 1A can prevent damage due to an increase in light intensity in the output mirror 14.

[0045] In a case where the first beam group B1 and the second beam group B2 are not tilted, a diffraction grating having a size twice or larger than the diffraction grating 12 included in the laser device 1A is required. Generally, it is difficult to manufacture a diffraction grating, and the manufacturing cost of a large diffraction grating is high. Therefore, by downsizing the diffraction grating 12, as in the laser device 1A of the first embodiment, the manufacturing cost of the laser device 1A can be reduced.

[0046] The collimating optical system 13 consists, for example, of two cylindrical lenses. Here, a description will be given of the configuration of a laser device in the case where the collimating optical system 13 consists of two cylindrical lenses.

[0047] Fig. Fig. 3 is a diagram illustrating the configuration of the laser device according to the first embodiment in the case where the collimating optical system consists of two cylindrical lenses. Components in Fig. 3, which has the same functions as those in Fig. 2 illustrated laser device 1A are given the same reference numerals as those in Fig. 2 and a redundant description is omitted.

[0048] A laser device 1B is an example of the laser device 1. The laser device 1B is a laser device in a case where the collimating optical system 13 is composed of two cylindrical lenses 21a and 21b. As with the laser device 1A, the laser device 1B includes the first laser device LD1, the second laser device LD2, the converging optical system 11, the diffraction grating 12, two of the cylindrical lenses 21a and 21b as an example of the collimating optical system 13, and the output mirror 14. In the laser device 1B, the first laser device LD1, the second laser device LD2, the converging optical system 11, the diffraction grating 12, two of the cylindrical lenses 21a and 21b as the collimating optical system 13, and the output mirror 14 are arranged at similar positions to those in the laser device 1A.

[0049] For example, among surfaces of each of the cylindrical lenses 21a and 21b, an incident surface (upper surface) onto which a corresponding one of the first beam group B1 and the second beam group B2 is incident is a convex surface, and an exit surface (lower surface) from which a corresponding one of the first beam group B1 and the second beam group B2 exits is a flat surface. When the cylindrical lenses 21a and 21b are viewed from a direction perpendicular to the first beam group B1 exiting the diffraction grating 12 and the z-axis direction, a side surface of each of the cylindrical lenses 21a and 21b has a shape of a portion of an arc or elliptical arc on the incident surface side and is straight on the exit surface side.It should be noted that the cylindrical lenses 21a and 21b may each have the exit surface, which is a convex surface, and the incident surface, which is a flat surface.

[0050] The cylindrical lenses 21a and 21b are arranged side by side in a direction (z-axis direction) perpendicular to an optical axis of the first beam group B1 and an optical axis of the second beam group B2, which are incident on the partial reflection surface 140 of the output mirror 14.

[0051] The cylindrical lenses 21a and 21b collimate the first beam group B1 and the second beam group B2 so that the first beam group B1 and the second beam group B2 impinge perpendicularly on the partial reflection surface 140 of the output mirror 14 while being spatially separated.

[0052] The first beam group B1 emitted by the first laser device LD1 is transmitted to the diffraction grating 12 via the converging optical system 11. The second beam group B2 emitted by the second laser device LD2 is transmitted to the diffraction grating 12 via the converging optical system 11. The diffraction grating 12 rotates the first beam group B1 and the second beam group B2 around the rotation axis set to the axial direction parallel to the z-axis direction and transmits the first beam group B1 and the second beam group B2 to the collimating optical system 13.

[0053] The first beam group B1 exiting the diffraction grating 12 is sent to the cylindrical lens 21b, and the second beam group B2 exiting the diffraction grating 12 is sent to the cylindrical lens 21a. The cylindrical lens 21b diffracts the first beam group B1 so that the first beam group B1 becomes a beam group in a plane parallel to the xy plane and reaches the partial reflection surface 140 of the output mirror 14. The cylindrical lens 21a diffracts the second beam group B2 so that the second beam group B2 becomes a beam group in a plane parallel to the xy plane and reaches the partial reflection surface 140 of the output mirror 14.

[0054] As described above, the cylindrical lenses 21a and 21b collimate the first beam group B1 and the second beam group B2 so that there is no overlap therebetween, and cause the first beam group B1 and the second beam group B2, which have been collimated, to reach the partial reflection surface 140 of the output mirror 14. Note that the collimating optical system 13 may be a lens arrangement in which two cylindrical lenses are joined in the z-axis direction.

[0055] Alternatively, the collimating optical system 13 may be composed of a cylindrical lens. Here, a description will be given of the configuration of a laser device in the case where the collimating optical system 13 is composed of a cylindrical lens.

[0056] Fig. Fig. 4 is a diagram illustrating a configuration of a laser device according to the first embodiment in the case where the collimating optical system consists of a cylindrical lens. Components in Fig. 4, which has the same functions as those in the Fig. 2 or Fig. 3 illustrated laser devices 1A or 1B are given the same reference numerals as those in the Fig. 2 or Fig. 3 and a redundant description is omitted.

[0057] A laser device 1C is an example of the laser device 1. The laser device 1C is a laser device in a case where the collimating optical system 13 is composed of a cylindrical lens 22. Like the laser device 1B, the laser device 1C includes the converging optical system 11, the diffraction grating 12, the cylindrical lens 22 as an example of the collimating optical system 13, and the output mirror 14. Compared with the laser device 1B, the laser device 1C includes the cylindrical lens 22 instead of two of the cylindrical lenses 21a and 21b. In the laser device 1C, the first laser device LD1, the second laser device LD2, the converging optical system 11, the diffraction grating 12, a unit of the cylindrical lens 22 as the collimating optical system 13, and the output mirror 14 are arranged at similar positions as in the laser device 1B.

[0058] The cylindrical lens 22 is a cylindrical lens having a focal length of “f” and arranged at a position away from the intersection point 120 on the side of the partial reflection surface 140 by the distance “f” which is a first distance.

[0059] Among surfaces of the cylindrical lens 22, an incident surface (upper surface) onto which the first beam group B1 and the second beam group B2 are incident is a convex surface, and an exit surface (lower surface) from which the first beam group B1 and the second beam group B2 exit is a flat surface. When the cylindrical lens 22 is viewed from a direction perpendicular to the first beam group B1 exiting the diffraction grating 12 and the z-axis direction, a side surface of the cylindrical lens 22 has a shape of a portion of an arc or elliptical arc on the incident surface side and is straight on the exit surface side. Note that the cylindrical lens 22 may have the exit surface being a convex surface and the incident surface being a flat surface.

[0060] The cylindrical lens 22 collimates the first beam group B1 and the second beam group B2 so that the first beam group B1 and the second beam group B2 impinge perpendicularly on the partial reflection surface 140 of the output mirror 14 while being spatially separated. That is, the cylindrical lens 22 diffracts the first beam group B1 and the second beam group B2 so that the first beam group B1 and the second beam group B2 each become a beam group in a plane parallel to the xy plane and reach the partial reflection surface 140 of the output mirror 14.

[0061] As described above, the cylindrical lens 22 collimates the first beam group B1 and the second beam group B2 so that there is no overlap therebetween, and causes the collimated first beam group B1 and the second beam group B2 to reach the partial reflection surface 140 of the output mirror 14. Note that the laser devices 1A to 1C may each include three or more laser devices.

[0062] As described above, in the laser devices 1A to 1C of the first embodiment, the first laser device LD1 and the second laser device LD2 cause the first beam group B1 and the second beam group B2, which are not parallel to each other, to be incident on the converging optical system 11. Then, the converging optical system 11 converges the first beam group B1 so that the first beam group B1 is superimposed on each other, and converges the second beam group B2 so that the second beam group B2 is superimposed on each other in the stage after the converging optical system 11.Furthermore, the diffraction grating 12 is arranged at the intersection point where the first beam group B1 and the second beam group B2 are at least partially superimposed on each other, the diffraction grating 12 having the diffraction effect in the plane 50 (the plane parallel to the xy plane) which is perpendicular to the direction parallel to the z-axis, which is the direction perpendicular to the direction (the direction parallel to the y-axis direction) in which the light-emitting points in the first laser device LD1 are arranged, and to the direction (the direction parallel to the y-axis direction) in which the light-emitting points in the second laser device LD2 are arranged.

[0063] With such a configuration, the laser devices 1A to 1C converge the first beam group B1 and the second beam group B2, thereby being able to output the laser light 7 with high power. Furthermore, the laser devices 1A to 1C can reduce the incident area of ​​the first beam group B1 and the second beam group B2 incident on the diffraction grating 12, thus avoiding an increase in the size of the diffraction grating 12. Therefore, the laser devices 1A to 1C can output the laser light 7 with high power using the diffraction grating 12, which is small and inexpensive. Second embodiment.

[0064] Next, a second embodiment will be described with reference to the Fig. 5 to 8. In the second embodiment, a superimposing optical system is arranged at a stage before the converging optical system 11, so that the first beam group B1 and the second beam group B2 emitted in parallel from the first laser device LD1 and the second laser device LD2 are superimposed in the diffraction grating 12.

[0065] Fig. 5 is a schematic diagram illustrating a schematic configuration of a laser device according to the first embodiment. Fig. Figure 5 illustrates a configuration of a laser device 2A when the laser device 2A is viewed from the y-axis direction. Components in Fig. 5, which has the same functions as those in Fig. 2 illustrated laser device 1A are given the same reference numerals as those in Fig. 2 and a redundant description is omitted.

[0066] The laser device 2A is an example of the laser device 1. The laser device 2A differs from the laser device 1A in the orientations in which the first laser device LD1 and the second laser device LD2 are arranged. Furthermore, the laser device 2A includes, in addition to the components included in the laser device 1A, a superimposing optical system 30. That is, the laser device 2A includes the superimposing optical system 30, the converging optical system 11, the diffraction grating 12, the collimating optical system 13, and the output mirror 14.

[0067] The superimposing optical system 30 is arranged at a stage after the first and second laser devices LD1 and LD2 and before the converging optical system 11.

[0068] In the laser device 2A, the first laser device LD1 and the second laser device LD2 are arranged spaced apart from each other in the z-axis direction. The first laser device LD1 and the second laser device LD2 are arranged in parallel and each emits beams in a direction parallel to the x-axis direction.

[0069] The surface on which the light-emitting points are arranged in the first laser device LD1 is a surface parallel to the yz plane. The surface on which the light-emitting points are arranged in the second laser device LD2 is a surface parallel to the yz plane. Thus, the surface on which the light-emitting points are arranged in the first laser device LD1 and the surface on which the light-emitting points are arranged in the second laser device LD2 are parallel to each other. Therefore, the first emission direction of the first beam group B1 and the second emission direction of the second beam group B2 are parallel to each other.

[0070] The superimposed optical system 30 changes the direction of movement of the first beam group B1 and the second beam group B2 so that the first beam group B1 and the second beam group B2 each impinge on the converging optical system 11 at the incident angle described in the first embodiment. That is, the superimposed optical system 30 converges the first beam group B1 and the second beam group B2 so that the first beam group B1 and the second beam group B2 intersect at the intersection point 120. The superimposed optical system 30 changes the directions of the optical axes of the first beam group B1 and the second beam group B2.

[0071] The superimposing optical system 30 changes the direction of the optical axis of the first beam group B1 from a direction parallel to the x-axis to an optical axis direction rotated in a plane parallel to the xz-plane. The superimposing optical system 30 changes the direction of the optical axis of the second beam group B2 from a direction parallel to the x-axis to an optical axis direction rotated in a plane parallel to the xz-plane. The angle by which the first beam group B1 is rotated and the angle by which the second beam group B2 is rotated are equal in magnitude and opposite in rotation direction. The converging optical system 11, the diffraction grating 12, the collimating optical system 13, and the output mirror 14 are the same as those in the first embodiment.

[0072] As described above, in the laser device 2A, the first beam group B1 and the second beam group B2 are inclined, so that, like the laser device 1A of the first embodiment, it is possible to avoid an increase in the size of the diffraction grating 12 and to prevent an increase in the beam intensity at the output mirror 14.

[0073] The superimposed optical system 30 consists, for example, of two eccentric lenses. Here, a description will be given of the configuration of a laser device in the case where the superimposed optical system 30 consists of two eccentric lenses.

[0074] Fig. Fig. 6 is a diagram illustrating the configuration of the laser device according to the second embodiment in the case where the superimposed optical system consists of two eccentric lenses. Components in Fig. 6, which has the same functions as those in Fig. 5 illustrated laser device 2A are provided with the same reference numerals as those in Fig. 5, and redundant description will be omitted. Note that the second embodiment describes a case where the collimating optical system 13 is composed of the cylindrical lenses 21a and 21b, but the collimating optical system 13 may be composed of the cylindrical lens 22.

[0075] A laser device 2B is an example of the laser device 1. The laser device 2B is a laser device in a case where the superimposed optical system 30 consists of two eccentric lenses 31 and 32. Like the laser device 2A, the laser device 2B includes two of the eccentric lenses 31 and 32 as the superimposed optical system 30, the converging optical system 11, the diffraction grating 12, the cylindrical lenses 21a and 21b as the collimating optical system 13, and the output mirror 14. The eccentric lens 31 is a first eccentric lens, and the eccentric lens 32 is a second eccentric lens. The eccentric lenses 31 and 32 are, for example, cylindrical lenses.

[0076] In the laser device 2B, the first laser device LD1, the second laser device LD2, the superimposing optical system 30 (which here consists of two of the eccentric lenses 31 and 32), the converging optical system 11, the diffraction grating 12, the collimating optical system 13 (which here consists of the cylindrical lenses 21a and 21b) and the output mirror 14 are arranged at similar positions as in the laser device 2A.

[0077] The eccentric lens 31 is arranged eccentrically to the side of the second laser device LD2, between the first laser device LD1 and the diffraction grating 12. The eccentric lens 32 is arranged eccentrically to the side of the first laser device LD1, between the second laser device LD2 and the diffraction grating 12.

[0078] Among surfaces of each of the eccentric lenses 31 and 32, an incident surface (upper surface) onto which a corresponding one of the first ray group B1 and the second ray group B2 is incident is a flat surface, and an exit surface (lower surface) from which a corresponding one of the first ray group B1 and the second ray group B2 is exited is a convex surface. When the eccentric lenses 31 and 32 are viewed from a direction perpendicular to the first ray group B1 incident on the converging optical system 11 and the z-axis direction, a side surface of each of the eccentric lenses 31 and 32 has a shape of a portion of an arc or elliptical arc on the exit surface side and is straight on the incident surface side. Note that the eccentric lenses 31 and 32 may each have the incident surface, which is a convex surface, and the exit surface, which is a flat surface.

[0079] In the laser device 2B, the first beam group B1 emitted by the first laser device LD1 is sent to the eccentric lens 31. The second beam group B2 emitted by the second laser device LD2 is sent to the eccentric lens 32.

[0080] The eccentric lens 31 rotates the first beam group B1 parallel to the x-axis direction around a rotation axis, which is a direction parallel to the y-axis direction. The eccentric lens 32 rotates the second beam group B2 parallel to the x-axis direction around a rotation axis, which is a direction parallel to the y-axis direction. Consequently, the first beam group B1 and the second beam group B2 each impinge at the angle described with reference to Fig. 5 and the incident angle on the converging optical system 11 described in the first embodiment. The converging optical system 11, the diffraction grating 12, the collimating optical system 13, and the output mirror 14 are the same as those in the first embodiment.

[0081] As described above, the superimposing optical system 30 includes the eccentric lenses 31 and 32, so that the intersection angle between the first beam group B1 and the second beam group B2 can be easily changed by the degree of eccentricity of the eccentric lenses 31 and 32.

[0082] It should be noted that the superimposed optical system 30 may include only one of the eccentric lenses 31 and 32. In this case, the superimposed optical system 30 includes one of the two eccentric lenses 31 and 32 and the other components except the eccentric lenses 31 and 32. Thus, the superimposed optical system 30 only needs to include at least one of the eccentric lenses 31 and 32.

[0083] Note that the superimposed optical system 30 may be a deflection mirror. Here, a description will be given of the configuration of a laser device in the case where the superimposed optical system 30 is composed of the deflection mirror.

[0084] Fig. Fig. 7 is a diagram illustrating the configuration of the laser device according to the second embodiment in the case where the superimposed optical system consists of two deflection mirrors. Components in Fig. 7, which has the same functions as those in the Fig. 5 or Fig. 6 illustrated laser devices 2A or 2B are given the same reference numerals as those in the Fig. 5 or Fig. 6 and a redundant description is omitted.

[0085] A laser device 2C is an example of the laser device 1. The laser device 2C is a laser device in a case where the superimposed optical system 30 consists of deflection mirrors 33 and 34.

[0086] As with the laser device 2A, the laser device 2C includes two of the deflection mirrors 33 and 34 as the superimposing optical system 30, the converging optical system 11, the diffraction grating 12, the cylindrical lenses 21a and 21b as the collimating optical system 13, and the output mirror 14. The deflection mirror 33 is a first deflection mirror, and the deflection mirror 34 is a second deflection mirror.

[0087] In the laser device 2C, the first laser device LD1, the second laser device LD2, the superposing optical system 30 (consisting of two of the deflecting mirrors 33 and 34), the converging optical system 11, the diffraction grating 12, the collimating optical system 13 (consisting of the cylindrical lenses 21a and 21b), and the output mirror 14 are arranged at similar positions as in the laser device 2A.

[0088] The deflection mirror 33 is arranged between the first laser device LD1 and the diffraction grating 12 and deflects the first beam group B1. The deflection mirror 34 is arranged between the second laser device LD2 and the diffraction grating 12 and deflects the second beam group B2.

[0089] In the laser device 2C, the first beam group B1 emitted by the first laser device LD1 is sent to the deflection mirror 33. The second beam group B2 emitted by the second laser device LD2 is sent to the deflection mirror 34.

[0090] The deflection mirror 33 rotates the first beam group B1 parallel to the x-axis direction around a rotation axis, which is a direction parallel to the y-axis direction. The deflection mirror 34 rotates the second beam group B2 parallel to the x-axis direction around a rotation axis, which is a direction parallel to the y-axis direction. Consequently, the first beam group B1 and the second beam group B2 each impinge at the angle determined with reference to the Fig. 5 and Fig. 6 and the incident angle on the converging optical system 11 described in the first embodiment. The converging optical system 11, the diffraction grating 12, the collimating optical system 13, and the output mirror 14 are the same as those in the first embodiment.

[0091] As described above, the superimposing optical system 30 includes the deflection mirrors 33 and 34, so that by installing angles of the deflection mirrors 33 and 34, the intersection angle between the first beam group B1 and the second beam group B2 can be easily changed.

[0092] It should be noted that the superimposed optical system 30 may include only one of the deflection mirrors 33 and 34. In this case, the superimposed optical system 30 includes one of the two deflection mirrors 33 and 34 and the other components except the deflection mirrors 33 and 34. Thus, the superimposed optical system 30 only needs to include at least one of the deflection mirrors 33 and 34. For example, the superimposed optical system 30 may include the eccentric lens 31 and the deflection mirror 34, or may include the eccentric lens 32 and the deflection mirror 33.

[0093] Furthermore, the first laser device LD1 may be arranged at the position described in the first embodiment, and the second laser device LD2 may be arranged at the position described in the second embodiment. In this case, the eccentric lens 32 or the deflection mirror 34 is arranged in the stage after the second laser device LD2.

[0094] Alternatively, the second laser device LD2 may be arranged at the position described in the first embodiment, and the first laser device LD1 may be arranged at the position described in the second embodiment. In this case, the eccentric lens 31 or the deflection mirror 33 is arranged in the stage after the first laser device LD1.

[0095] At this point, a laser device of a comparative example is described. Fig. Figure 8 is a schematic diagram illustrating a schematic configuration of the laser device of the comparative example. A laser device 1X of the comparative example includes the first laser device LD1, the second laser device LD2, the converging optical system 11, a diffraction grating 15, and the output mirror 14.

[0096] In the laser device 1X of the comparative example, the first laser device LD1 and the second laser device LD2 are arranged in parallel. The first laser device LD1 and the second laser device LD2 are spaced apart from each other in the z-axis direction. The first laser device LD1 emits the first beam group B1 in a direction parallel to the x-axis direction, and the second laser device LD2 emits the second beam group B2 in a direction parallel to the x-axis direction.

[0097] In the laser device 1X of the comparative example, the first beam group B1 and the second beam group B2 are incident on the converging optical system 11 while separated from each other. The converging optical system 11 causes the first beam group B1 to converge to be superimposed on the diffraction grating 15 and causes the second beam group B2 to converge to be superimposed on the diffraction grating 15.

[0098] The diffraction grating 15 rotates the first beam group B1 and the second beam group B2 around a rotation axis, which is an axial direction parallel to the z-axis direction, and sends the first beam group B1 and the second beam group B2 to the output mirror 14. Since the first beam group B1 and the second beam group B2 incident on the diffraction grating 15 are separated from each other, the diffraction grating 15 has a longer dimension in the z-axis direction than the diffraction grating 12. For this reason, the diffraction grating 15 is more expensive than the diffraction grating 12, and the manufacturing cost of the laser device 1X is higher than that of the laser device 1A.

[0099] As described above, the superimposed optical system 30 according to the second embodiment converges the first beam group B1 and the second beam group B2 so that the first beam group B1 and the second beam group B2 intersect at the intersection point 120, whereby the laser light 7 can be extracted with high power using the diffraction grating 12, which is small in size and inexpensive, as in the first embodiment.

[0100] The configurations illustrated in the above embodiments each illustrate an example, so that another known technique may be combined, the embodiments may be combined with each other, or the configurations may be partially omitted and / or modified without departing from the scope of the present disclosure. List of reference symbols

[0101] 1, 1A to 1C, 1X, 2A to 2C laser device; 3 converging optical system; 4 optical fiber; 5 processing optical system; 6 workpiece; 7 laser light; 11 converging optical system; 12, 15 diffraction grating; 13 collimating optical system; 14 output mirror; 21a, 21b, 22 cylindrical lens; 30 superimposing optical system; 31, 32 eccentric lens; 33, 34 deflecting mirror; 50 plane; 100 laser processing machine; 120 intersection point; 140 partial reflection surface; B1 first beam group; B2 second beam group; LD1 first laser device; LD2 second laser device.

Claims

[1] Laser device comprising: a first laser device for emitting a beam from each of a plurality of light-emitting points arranged in a first direction in a first emission direction perpendicular to the first direction and forming a first beam group; a second laser device for emitting a beam from each of a plurality of light-emitting points arranged in a second direction in a second emission direction perpendicular to the second direction, and forming a second beam group; an output mirror forming one end of a first external resonator, the other end of which is formed by the first laser device, forming one end of a second external resonator, the other end of which is formed by the second laser device, and including a partial reflection surface that reflects part of the first beam group and the second beam group and transmits the rest; a converging optical system for allowing non-parallel incidence of the first beam group and the second beam group on the converging optical system and, on one side of a subsequent stage, for converging the first beam group so that the first beam group is superimposed and for converging the second beam group so that the second beam group is superimposed; a diffraction grating arranged at an intersection point where at least a part of the first beam group and the second beam group is superimposed, and having a diffraction effect in a first plane perpendicular to a third direction, which is a direction perpendicular to the first direction and the second direction; and a collimating optical system arranged between the diffraction grating and the output mirror for collimating the first beam group and the second beam group so that the first beam group and the second beam group are incident perpendicularly on the partial reflection surface while being spatially separated from each other. [2] The laser device according to claim 1, wherein the first laser device and the second laser device are each arranged at an angle such that the first beam group and the second beam group intersect at the intersection point. [3] Laser device according to claim 1, wherein the first laser device and the second laser device emit the first beam group and the second beam group in parallel, and the laser device further comprises a superimposing optical system arranged at a stage before the converging optical system for converging the first beam group and the second beam group so that the first beam group and the second beam group intersect at the intersection point. [4] A laser device according to claim 3, wherein the superimposing optical system includes: at least one of a first eccentric lens arranged eccentrically laterally of the second laser device between the first laser device and the diffraction grating, or a second eccentric lens arranged eccentrically laterally of the first laser device between the second laser device and the diffraction grating. [5] A laser device according to claim 3, wherein the superimposing optical system includes: at least one of a first deflection mirror arranged between the first laser device and the diffraction grating for deflecting the first beam group, or a second deflection mirror arranged between the second laser device and the diffraction grating for deflecting the second beam group. [6] A laser device according to any one of claims 1 to 5, wherein the collimating optical system consists of two cylindrical lenses arrayed in a direction perpendicular to an optical axis of the first beam group and an optical axis of the second beam group incident on the partial reflection surface, or a lens array in which the two of the cylindrical lenses are joined together. [7] A laser device according to any one of claims 1 to 5, wherein the collimating optical system consists of a cylindrical lens arranged at a position remote from the intersection point on one side of the partial reflection surface by a first distance and having a focal length which is the first distance. [8] Laser processing machine, comprising: a laser device for emitting laser light; a concentrating optical system for concentrating the laser light; an optical transmission line for transmitting the laser light concentrated by the concentrating optical system; and a processing optical system for concentrating the laser light transmitted through the optical transmission line onto an object to be processed, wherein the laser device includes: a first laser device for emitting a beam from each of a plurality of light-emitting points arranged in a first direction in a first emission direction perpendicular to the first direction and forming a first beam group; a second laser device for emitting a beam from each of a plurality of light-emitting points arranged in a second direction in a second emission direction perpendicular to the second direction, and forming a second beam group; an output mirror forming one end of a first external resonator whose other end is formed by the first laser device, forming one end of a second external resonator whose other end is formed by the second laser device, and including a partial reflection surface that reflects part of the first beam group and the second beam group and transmits the rest as the laser light; a converging optical system for allowing non-parallel incidence of the first beam group and the second beam group on the converging optical system and, on one side of a subsequent stage, for converging the first beam group so that the first beam group is superimposed and for converging the second beam group so that the second beam group is superimposed; a diffraction grating arranged at an intersection point where at least a part of the first beam group and the second beam group is superimposed, and having a diffraction effect in a first plane perpendicular to a third direction, which is a direction perpendicular to the first direction and the second direction; and a collimating optical system arranged between the diffraction grating and the output mirror for collimating the first beam group and the second beam group so that the first beam group and the second beam group are incident perpendicularly on the partial reflection surface while being spatially separated from each other.

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